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1/*
2 * SPI init/core code
3 *
4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#include <linux/kernel.h>
23#include <linux/kmod.h>
24#include <linux/device.h>
25#include <linux/init.h>
26#include <linux/cache.h>
27#include <linux/dma-mapping.h>
28#include <linux/dmaengine.h>
29#include <linux/mutex.h>
30#include <linux/of_device.h>
31#include <linux/of_irq.h>
32#include <linux/slab.h>
33#include <linux/mod_devicetable.h>
34#include <linux/spi/spi.h>
35#include <linux/of_gpio.h>
36#include <linux/pm_runtime.h>
37#include <linux/export.h>
38#include <linux/sched/rt.h>
39#include <linux/delay.h>
40#include <linux/kthread.h>
41#include <linux/ioport.h>
42#include <linux/acpi.h>
43
44#define CREATE_TRACE_POINTS
45#include <trace/events/spi.h>
46
47static void spidev_release(struct device *dev)
48{
49 struct spi_device *spi = to_spi_device(dev);
50
51 /* spi masters may cleanup for released devices */
52 if (spi->master->cleanup)
53 spi->master->cleanup(spi);
54
55 spi_master_put(spi->master);
56 kfree(spi);
57}
58
59static ssize_t
60modalias_show(struct device *dev, struct device_attribute *a, char *buf)
61{
62 const struct spi_device *spi = to_spi_device(dev);
63 int len;
64
65 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 if (len != -ENODEV)
67 return len;
68
69 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
70}
71static DEVICE_ATTR_RO(modalias);
72
73static struct attribute *spi_dev_attrs[] = {
74 &dev_attr_modalias.attr,
75 NULL,
76};
77ATTRIBUTE_GROUPS(spi_dev);
78
79/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
80 * and the sysfs version makes coldplug work too.
81 */
82
83static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
84 const struct spi_device *sdev)
85{
86 while (id->name[0]) {
87 if (!strcmp(sdev->modalias, id->name))
88 return id;
89 id++;
90 }
91 return NULL;
92}
93
94const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
95{
96 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
97
98 return spi_match_id(sdrv->id_table, sdev);
99}
100EXPORT_SYMBOL_GPL(spi_get_device_id);
101
102static int spi_match_device(struct device *dev, struct device_driver *drv)
103{
104 const struct spi_device *spi = to_spi_device(dev);
105 const struct spi_driver *sdrv = to_spi_driver(drv);
106
107 /* Attempt an OF style match */
108 if (of_driver_match_device(dev, drv))
109 return 1;
110
111 /* Then try ACPI */
112 if (acpi_driver_match_device(dev, drv))
113 return 1;
114
115 if (sdrv->id_table)
116 return !!spi_match_id(sdrv->id_table, spi);
117
118 return strcmp(spi->modalias, drv->name) == 0;
119}
120
121static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
122{
123 const struct spi_device *spi = to_spi_device(dev);
124 int rc;
125
126 rc = acpi_device_uevent_modalias(dev, env);
127 if (rc != -ENODEV)
128 return rc;
129
130 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
131 return 0;
132}
133
134#ifdef CONFIG_PM_SLEEP
135static int spi_legacy_suspend(struct device *dev, pm_message_t message)
136{
137 int value = 0;
138 struct spi_driver *drv = to_spi_driver(dev->driver);
139
140 /* suspend will stop irqs and dma; no more i/o */
141 if (drv) {
142 if (drv->suspend)
143 value = drv->suspend(to_spi_device(dev), message);
144 else
145 dev_dbg(dev, "... can't suspend\n");
146 }
147 return value;
148}
149
150static int spi_legacy_resume(struct device *dev)
151{
152 int value = 0;
153 struct spi_driver *drv = to_spi_driver(dev->driver);
154
155 /* resume may restart the i/o queue */
156 if (drv) {
157 if (drv->resume)
158 value = drv->resume(to_spi_device(dev));
159 else
160 dev_dbg(dev, "... can't resume\n");
161 }
162 return value;
163}
164
165static int spi_pm_suspend(struct device *dev)
166{
167 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168
169 if (pm)
170 return pm_generic_suspend(dev);
171 else
172 return spi_legacy_suspend(dev, PMSG_SUSPEND);
173}
174
175static int spi_pm_resume(struct device *dev)
176{
177 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178
179 if (pm)
180 return pm_generic_resume(dev);
181 else
182 return spi_legacy_resume(dev);
183}
184
185static int spi_pm_freeze(struct device *dev)
186{
187 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188
189 if (pm)
190 return pm_generic_freeze(dev);
191 else
192 return spi_legacy_suspend(dev, PMSG_FREEZE);
193}
194
195static int spi_pm_thaw(struct device *dev)
196{
197 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198
199 if (pm)
200 return pm_generic_thaw(dev);
201 else
202 return spi_legacy_resume(dev);
203}
204
205static int spi_pm_poweroff(struct device *dev)
206{
207 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208
209 if (pm)
210 return pm_generic_poweroff(dev);
211 else
212 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
213}
214
215static int spi_pm_restore(struct device *dev)
216{
217 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
218
219 if (pm)
220 return pm_generic_restore(dev);
221 else
222 return spi_legacy_resume(dev);
223}
224#else
225#define spi_pm_suspend NULL
226#define spi_pm_resume NULL
227#define spi_pm_freeze NULL
228#define spi_pm_thaw NULL
229#define spi_pm_poweroff NULL
230#define spi_pm_restore NULL
231#endif
232
233static const struct dev_pm_ops spi_pm = {
234 .suspend = spi_pm_suspend,
235 .resume = spi_pm_resume,
236 .freeze = spi_pm_freeze,
237 .thaw = spi_pm_thaw,
238 .poweroff = spi_pm_poweroff,
239 .restore = spi_pm_restore,
240 SET_RUNTIME_PM_OPS(
241 pm_generic_runtime_suspend,
242 pm_generic_runtime_resume,
243 NULL
244 )
245};
246
247struct bus_type spi_bus_type = {
248 .name = "spi",
249 .dev_groups = spi_dev_groups,
250 .match = spi_match_device,
251 .uevent = spi_uevent,
252 .pm = &spi_pm,
253};
254EXPORT_SYMBOL_GPL(spi_bus_type);
255
256
257static int spi_drv_probe(struct device *dev)
258{
259 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
260 int ret;
261
262 acpi_dev_pm_attach(dev, true);
263 ret = sdrv->probe(to_spi_device(dev));
264 if (ret)
265 acpi_dev_pm_detach(dev, true);
266
267 return ret;
268}
269
270static int spi_drv_remove(struct device *dev)
271{
272 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
273 int ret;
274
275 ret = sdrv->remove(to_spi_device(dev));
276 acpi_dev_pm_detach(dev, true);
277
278 return ret;
279}
280
281static void spi_drv_shutdown(struct device *dev)
282{
283 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
284
285 sdrv->shutdown(to_spi_device(dev));
286}
287
288/**
289 * spi_register_driver - register a SPI driver
290 * @sdrv: the driver to register
291 * Context: can sleep
292 */
293int spi_register_driver(struct spi_driver *sdrv)
294{
295 sdrv->driver.bus = &spi_bus_type;
296 if (sdrv->probe)
297 sdrv->driver.probe = spi_drv_probe;
298 if (sdrv->remove)
299 sdrv->driver.remove = spi_drv_remove;
300 if (sdrv->shutdown)
301 sdrv->driver.shutdown = spi_drv_shutdown;
302 return driver_register(&sdrv->driver);
303}
304EXPORT_SYMBOL_GPL(spi_register_driver);
305
306/*-------------------------------------------------------------------------*/
307
308/* SPI devices should normally not be created by SPI device drivers; that
309 * would make them board-specific. Similarly with SPI master drivers.
310 * Device registration normally goes into like arch/.../mach.../board-YYY.c
311 * with other readonly (flashable) information about mainboard devices.
312 */
313
314struct boardinfo {
315 struct list_head list;
316 struct spi_board_info board_info;
317};
318
319static LIST_HEAD(board_list);
320static LIST_HEAD(spi_master_list);
321
322/*
323 * Used to protect add/del opertion for board_info list and
324 * spi_master list, and their matching process
325 */
326static DEFINE_MUTEX(board_lock);
327
328/**
329 * spi_alloc_device - Allocate a new SPI device
330 * @master: Controller to which device is connected
331 * Context: can sleep
332 *
333 * Allows a driver to allocate and initialize a spi_device without
334 * registering it immediately. This allows a driver to directly
335 * fill the spi_device with device parameters before calling
336 * spi_add_device() on it.
337 *
338 * Caller is responsible to call spi_add_device() on the returned
339 * spi_device structure to add it to the SPI master. If the caller
340 * needs to discard the spi_device without adding it, then it should
341 * call spi_dev_put() on it.
342 *
343 * Returns a pointer to the new device, or NULL.
344 */
345struct spi_device *spi_alloc_device(struct spi_master *master)
346{
347 struct spi_device *spi;
348 struct device *dev = master->dev.parent;
349
350 if (!spi_master_get(master))
351 return NULL;
352
353 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
354 if (!spi) {
355 dev_err(dev, "cannot alloc spi_device\n");
356 spi_master_put(master);
357 return NULL;
358 }
359
360 spi->master = master;
361 spi->dev.parent = &master->dev;
362 spi->dev.bus = &spi_bus_type;
363 spi->dev.release = spidev_release;
364 spi->cs_gpio = -ENOENT;
365 device_initialize(&spi->dev);
366 return spi;
367}
368EXPORT_SYMBOL_GPL(spi_alloc_device);
369
370static void spi_dev_set_name(struct spi_device *spi)
371{
372 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
373
374 if (adev) {
375 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
376 return;
377 }
378
379 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
380 spi->chip_select);
381}
382
383static int spi_dev_check(struct device *dev, void *data)
384{
385 struct spi_device *spi = to_spi_device(dev);
386 struct spi_device *new_spi = data;
387
388 if (spi->master == new_spi->master &&
389 spi->chip_select == new_spi->chip_select)
390 return -EBUSY;
391 return 0;
392}
393
394/**
395 * spi_add_device - Add spi_device allocated with spi_alloc_device
396 * @spi: spi_device to register
397 *
398 * Companion function to spi_alloc_device. Devices allocated with
399 * spi_alloc_device can be added onto the spi bus with this function.
400 *
401 * Returns 0 on success; negative errno on failure
402 */
403int spi_add_device(struct spi_device *spi)
404{
405 static DEFINE_MUTEX(spi_add_lock);
406 struct spi_master *master = spi->master;
407 struct device *dev = master->dev.parent;
408 int status;
409
410 /* Chipselects are numbered 0..max; validate. */
411 if (spi->chip_select >= master->num_chipselect) {
412 dev_err(dev, "cs%d >= max %d\n",
413 spi->chip_select,
414 master->num_chipselect);
415 return -EINVAL;
416 }
417
418 /* Set the bus ID string */
419 spi_dev_set_name(spi);
420
421 /* We need to make sure there's no other device with this
422 * chipselect **BEFORE** we call setup(), else we'll trash
423 * its configuration. Lock against concurrent add() calls.
424 */
425 mutex_lock(&spi_add_lock);
426
427 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
428 if (status) {
429 dev_err(dev, "chipselect %d already in use\n",
430 spi->chip_select);
431 goto done;
432 }
433
434 if (master->cs_gpios)
435 spi->cs_gpio = master->cs_gpios[spi->chip_select];
436
437 /* Drivers may modify this initial i/o setup, but will
438 * normally rely on the device being setup. Devices
439 * using SPI_CS_HIGH can't coexist well otherwise...
440 */
441 status = spi_setup(spi);
442 if (status < 0) {
443 dev_err(dev, "can't setup %s, status %d\n",
444 dev_name(&spi->dev), status);
445 goto done;
446 }
447
448 /* Device may be bound to an active driver when this returns */
449 status = device_add(&spi->dev);
450 if (status < 0)
451 dev_err(dev, "can't add %s, status %d\n",
452 dev_name(&spi->dev), status);
453 else
454 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
455
456done:
457 mutex_unlock(&spi_add_lock);
458 return status;
459}
460EXPORT_SYMBOL_GPL(spi_add_device);
461
462/**
463 * spi_new_device - instantiate one new SPI device
464 * @master: Controller to which device is connected
465 * @chip: Describes the SPI device
466 * Context: can sleep
467 *
468 * On typical mainboards, this is purely internal; and it's not needed
469 * after board init creates the hard-wired devices. Some development
470 * platforms may not be able to use spi_register_board_info though, and
471 * this is exported so that for example a USB or parport based adapter
472 * driver could add devices (which it would learn about out-of-band).
473 *
474 * Returns the new device, or NULL.
475 */
476struct spi_device *spi_new_device(struct spi_master *master,
477 struct spi_board_info *chip)
478{
479 struct spi_device *proxy;
480 int status;
481
482 /* NOTE: caller did any chip->bus_num checks necessary.
483 *
484 * Also, unless we change the return value convention to use
485 * error-or-pointer (not NULL-or-pointer), troubleshootability
486 * suggests syslogged diagnostics are best here (ugh).
487 */
488
489 proxy = spi_alloc_device(master);
490 if (!proxy)
491 return NULL;
492
493 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
494
495 proxy->chip_select = chip->chip_select;
496 proxy->max_speed_hz = chip->max_speed_hz;
497 proxy->mode = chip->mode;
498 proxy->irq = chip->irq;
499 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
500 proxy->dev.platform_data = (void *) chip->platform_data;
501 proxy->controller_data = chip->controller_data;
502 proxy->controller_state = NULL;
503
504 status = spi_add_device(proxy);
505 if (status < 0) {
506 spi_dev_put(proxy);
507 return NULL;
508 }
509
510 return proxy;
511}
512EXPORT_SYMBOL_GPL(spi_new_device);
513
514static void spi_match_master_to_boardinfo(struct spi_master *master,
515 struct spi_board_info *bi)
516{
517 struct spi_device *dev;
518
519 if (master->bus_num != bi->bus_num)
520 return;
521
522 dev = spi_new_device(master, bi);
523 if (!dev)
524 dev_err(master->dev.parent, "can't create new device for %s\n",
525 bi->modalias);
526}
527
528/**
529 * spi_register_board_info - register SPI devices for a given board
530 * @info: array of chip descriptors
531 * @n: how many descriptors are provided
532 * Context: can sleep
533 *
534 * Board-specific early init code calls this (probably during arch_initcall)
535 * with segments of the SPI device table. Any device nodes are created later,
536 * after the relevant parent SPI controller (bus_num) is defined. We keep
537 * this table of devices forever, so that reloading a controller driver will
538 * not make Linux forget about these hard-wired devices.
539 *
540 * Other code can also call this, e.g. a particular add-on board might provide
541 * SPI devices through its expansion connector, so code initializing that board
542 * would naturally declare its SPI devices.
543 *
544 * The board info passed can safely be __initdata ... but be careful of
545 * any embedded pointers (platform_data, etc), they're copied as-is.
546 */
547int spi_register_board_info(struct spi_board_info const *info, unsigned n)
548{
549 struct boardinfo *bi;
550 int i;
551
552 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
553 if (!bi)
554 return -ENOMEM;
555
556 for (i = 0; i < n; i++, bi++, info++) {
557 struct spi_master *master;
558
559 memcpy(&bi->board_info, info, sizeof(*info));
560 mutex_lock(&board_lock);
561 list_add_tail(&bi->list, &board_list);
562 list_for_each_entry(master, &spi_master_list, list)
563 spi_match_master_to_boardinfo(master, &bi->board_info);
564 mutex_unlock(&board_lock);
565 }
566
567 return 0;
568}
569
570/*-------------------------------------------------------------------------*/
571
572static void spi_set_cs(struct spi_device *spi, bool enable)
573{
574 if (spi->mode & SPI_CS_HIGH)
575 enable = !enable;
576
577 if (spi->cs_gpio >= 0)
578 gpio_set_value(spi->cs_gpio, !enable);
579 else if (spi->master->set_cs)
580 spi->master->set_cs(spi, !enable);
581}
582
583#ifdef CONFIG_HAS_DMA
584static int spi_map_buf(struct spi_master *master, struct device *dev,
585 struct sg_table *sgt, void *buf, size_t len,
586 enum dma_data_direction dir)
587{
588 const bool vmalloced_buf = is_vmalloc_addr(buf);
589 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
590 const int sgs = DIV_ROUND_UP(len, desc_len);
591 struct page *vm_page;
592 void *sg_buf;
593 size_t min;
594 int i, ret;
595
596 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
597 if (ret != 0)
598 return ret;
599
600 for (i = 0; i < sgs; i++) {
601 min = min_t(size_t, len, desc_len);
602
603 if (vmalloced_buf) {
604 vm_page = vmalloc_to_page(buf);
605 if (!vm_page) {
606 sg_free_table(sgt);
607 return -ENOMEM;
608 }
609 sg_buf = page_address(vm_page) +
610 ((size_t)buf & ~PAGE_MASK);
611 } else {
612 sg_buf = buf;
613 }
614
615 sg_set_buf(&sgt->sgl[i], sg_buf, min);
616
617 buf += min;
618 len -= min;
619 }
620
621 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
622 if (ret < 0) {
623 sg_free_table(sgt);
624 return ret;
625 }
626
627 sgt->nents = ret;
628
629 return 0;
630}
631
632static void spi_unmap_buf(struct spi_master *master, struct device *dev,
633 struct sg_table *sgt, enum dma_data_direction dir)
634{
635 if (sgt->orig_nents) {
636 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
637 sg_free_table(sgt);
638 }
639}
640
641static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
642{
643 struct device *tx_dev, *rx_dev;
644 struct spi_transfer *xfer;
645 int ret;
646
647 if (!master->can_dma)
648 return 0;
649
650 tx_dev = &master->dma_tx->dev->device;
651 rx_dev = &master->dma_rx->dev->device;
652
653 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
654 if (!master->can_dma(master, msg->spi, xfer))
655 continue;
656
657 if (xfer->tx_buf != NULL) {
658 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
659 (void *)xfer->tx_buf, xfer->len,
660 DMA_TO_DEVICE);
661 if (ret != 0)
662 return ret;
663 }
664
665 if (xfer->rx_buf != NULL) {
666 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
667 xfer->rx_buf, xfer->len,
668 DMA_FROM_DEVICE);
669 if (ret != 0) {
670 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
671 DMA_TO_DEVICE);
672 return ret;
673 }
674 }
675 }
676
677 master->cur_msg_mapped = true;
678
679 return 0;
680}
681
682static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
683{
684 struct spi_transfer *xfer;
685 struct device *tx_dev, *rx_dev;
686
687 if (!master->cur_msg_mapped || !master->can_dma)
688 return 0;
689
690 tx_dev = &master->dma_tx->dev->device;
691 rx_dev = &master->dma_rx->dev->device;
692
693 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
694 if (!master->can_dma(master, msg->spi, xfer))
695 continue;
696
697 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
698 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
699 }
700
701 return 0;
702}
703#else /* !CONFIG_HAS_DMA */
704static inline int __spi_map_msg(struct spi_master *master,
705 struct spi_message *msg)
706{
707 return 0;
708}
709
710static inline int spi_unmap_msg(struct spi_master *master,
711 struct spi_message *msg)
712{
713 return 0;
714}
715#endif /* !CONFIG_HAS_DMA */
716
717static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
718{
719 struct spi_transfer *xfer;
720 void *tmp;
721 unsigned int max_tx, max_rx;
722
723 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
724 max_tx = 0;
725 max_rx = 0;
726
727 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
728 if ((master->flags & SPI_MASTER_MUST_TX) &&
729 !xfer->tx_buf)
730 max_tx = max(xfer->len, max_tx);
731 if ((master->flags & SPI_MASTER_MUST_RX) &&
732 !xfer->rx_buf)
733 max_rx = max(xfer->len, max_rx);
734 }
735
736 if (max_tx) {
737 tmp = krealloc(master->dummy_tx, max_tx,
738 GFP_KERNEL | GFP_DMA);
739 if (!tmp)
740 return -ENOMEM;
741 master->dummy_tx = tmp;
742 memset(tmp, 0, max_tx);
743 }
744
745 if (max_rx) {
746 tmp = krealloc(master->dummy_rx, max_rx,
747 GFP_KERNEL | GFP_DMA);
748 if (!tmp)
749 return -ENOMEM;
750 master->dummy_rx = tmp;
751 }
752
753 if (max_tx || max_rx) {
754 list_for_each_entry(xfer, &msg->transfers,
755 transfer_list) {
756 if (!xfer->tx_buf)
757 xfer->tx_buf = master->dummy_tx;
758 if (!xfer->rx_buf)
759 xfer->rx_buf = master->dummy_rx;
760 }
761 }
762 }
763
764 return __spi_map_msg(master, msg);
765}
766
767/*
768 * spi_transfer_one_message - Default implementation of transfer_one_message()
769 *
770 * This is a standard implementation of transfer_one_message() for
771 * drivers which impelment a transfer_one() operation. It provides
772 * standard handling of delays and chip select management.
773 */
774static int spi_transfer_one_message(struct spi_master *master,
775 struct spi_message *msg)
776{
777 struct spi_transfer *xfer;
778 bool keep_cs = false;
779 int ret = 0;
780 int ms = 1;
781
782 spi_set_cs(msg->spi, true);
783
784 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
785 trace_spi_transfer_start(msg, xfer);
786
787 reinit_completion(&master->xfer_completion);
788
789 ret = master->transfer_one(master, msg->spi, xfer);
790 if (ret < 0) {
791 dev_err(&msg->spi->dev,
792 "SPI transfer failed: %d\n", ret);
793 goto out;
794 }
795
796 if (ret > 0) {
797 ret = 0;
798 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
799 ms += 10; /* some tolerance */
800
801 ms = wait_for_completion_timeout(&master->xfer_completion,
802 msecs_to_jiffies(ms));
803 }
804
805 if (ms == 0) {
806 dev_err(&msg->spi->dev, "SPI transfer timed out\n");
807 msg->status = -ETIMEDOUT;
808 }
809
810 trace_spi_transfer_stop(msg, xfer);
811
812 if (msg->status != -EINPROGRESS)
813 goto out;
814
815 if (xfer->delay_usecs)
816 udelay(xfer->delay_usecs);
817
818 if (xfer->cs_change) {
819 if (list_is_last(&xfer->transfer_list,
820 &msg->transfers)) {
821 keep_cs = true;
822 } else {
823 spi_set_cs(msg->spi, false);
824 udelay(10);
825 spi_set_cs(msg->spi, true);
826 }
827 }
828
829 msg->actual_length += xfer->len;
830 }
831
832out:
833 if (ret != 0 || !keep_cs)
834 spi_set_cs(msg->spi, false);
835
836 if (msg->status == -EINPROGRESS)
837 msg->status = ret;
838
839 spi_finalize_current_message(master);
840
841 return ret;
842}
843
844/**
845 * spi_finalize_current_transfer - report completion of a transfer
846 *
847 * Called by SPI drivers using the core transfer_one_message()
848 * implementation to notify it that the current interrupt driven
849 * transfer has finished and the next one may be scheduled.
850 */
851void spi_finalize_current_transfer(struct spi_master *master)
852{
853 complete(&master->xfer_completion);
854}
855EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
856
857/**
858 * spi_pump_messages - kthread work function which processes spi message queue
859 * @work: pointer to kthread work struct contained in the master struct
860 *
861 * This function checks if there is any spi message in the queue that
862 * needs processing and if so call out to the driver to initialize hardware
863 * and transfer each message.
864 *
865 */
866static void spi_pump_messages(struct kthread_work *work)
867{
868 struct spi_master *master =
869 container_of(work, struct spi_master, pump_messages);
870 unsigned long flags;
871 bool was_busy = false;
872 int ret;
873
874 /* Lock queue and check for queue work */
875 spin_lock_irqsave(&master->queue_lock, flags);
876 if (list_empty(&master->queue) || !master->running) {
877 if (!master->busy) {
878 spin_unlock_irqrestore(&master->queue_lock, flags);
879 return;
880 }
881 master->busy = false;
882 spin_unlock_irqrestore(&master->queue_lock, flags);
883 kfree(master->dummy_rx);
884 master->dummy_rx = NULL;
885 kfree(master->dummy_tx);
886 master->dummy_tx = NULL;
887 if (master->unprepare_transfer_hardware &&
888 master->unprepare_transfer_hardware(master))
889 dev_err(&master->dev,
890 "failed to unprepare transfer hardware\n");
891 if (master->auto_runtime_pm) {
892 pm_runtime_mark_last_busy(master->dev.parent);
893 pm_runtime_put_autosuspend(master->dev.parent);
894 }
895 trace_spi_master_idle(master);
896 return;
897 }
898
899 /* Make sure we are not already running a message */
900 if (master->cur_msg) {
901 spin_unlock_irqrestore(&master->queue_lock, flags);
902 return;
903 }
904 /* Extract head of queue */
905 master->cur_msg =
906 list_first_entry(&master->queue, struct spi_message, queue);
907
908 list_del_init(&master->cur_msg->queue);
909 if (master->busy)
910 was_busy = true;
911 else
912 master->busy = true;
913 spin_unlock_irqrestore(&master->queue_lock, flags);
914
915 if (!was_busy && master->auto_runtime_pm) {
916 ret = pm_runtime_get_sync(master->dev.parent);
917 if (ret < 0) {
918 dev_err(&master->dev, "Failed to power device: %d\n",
919 ret);
920 return;
921 }
922 }
923
924 if (!was_busy)
925 trace_spi_master_busy(master);
926
927 if (!was_busy && master->prepare_transfer_hardware) {
928 ret = master->prepare_transfer_hardware(master);
929 if (ret) {
930 dev_err(&master->dev,
931 "failed to prepare transfer hardware\n");
932
933 if (master->auto_runtime_pm)
934 pm_runtime_put(master->dev.parent);
935 return;
936 }
937 }
938
939 trace_spi_message_start(master->cur_msg);
940
941 if (master->prepare_message) {
942 ret = master->prepare_message(master, master->cur_msg);
943 if (ret) {
944 dev_err(&master->dev,
945 "failed to prepare message: %d\n", ret);
946 master->cur_msg->status = ret;
947 spi_finalize_current_message(master);
948 return;
949 }
950 master->cur_msg_prepared = true;
951 }
952
953 ret = spi_map_msg(master, master->cur_msg);
954 if (ret) {
955 master->cur_msg->status = ret;
956 spi_finalize_current_message(master);
957 return;
958 }
959
960 ret = master->transfer_one_message(master, master->cur_msg);
961 if (ret) {
962 dev_err(&master->dev,
963 "failed to transfer one message from queue\n");
964 return;
965 }
966}
967
968static int spi_init_queue(struct spi_master *master)
969{
970 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
971
972 INIT_LIST_HEAD(&master->queue);
973 spin_lock_init(&master->queue_lock);
974
975 master->running = false;
976 master->busy = false;
977
978 init_kthread_worker(&master->kworker);
979 master->kworker_task = kthread_run(kthread_worker_fn,
980 &master->kworker, "%s",
981 dev_name(&master->dev));
982 if (IS_ERR(master->kworker_task)) {
983 dev_err(&master->dev, "failed to create message pump task\n");
984 return -ENOMEM;
985 }
986 init_kthread_work(&master->pump_messages, spi_pump_messages);
987
988 /*
989 * Master config will indicate if this controller should run the
990 * message pump with high (realtime) priority to reduce the transfer
991 * latency on the bus by minimising the delay between a transfer
992 * request and the scheduling of the message pump thread. Without this
993 * setting the message pump thread will remain at default priority.
994 */
995 if (master->rt) {
996 dev_info(&master->dev,
997 "will run message pump with realtime priority\n");
998 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
999 }
1000
1001 return 0;
1002}
1003
1004/**
1005 * spi_get_next_queued_message() - called by driver to check for queued
1006 * messages
1007 * @master: the master to check for queued messages
1008 *
1009 * If there are more messages in the queue, the next message is returned from
1010 * this call.
1011 */
1012struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1013{
1014 struct spi_message *next;
1015 unsigned long flags;
1016
1017 /* get a pointer to the next message, if any */
1018 spin_lock_irqsave(&master->queue_lock, flags);
1019 next = list_first_entry_or_null(&master->queue, struct spi_message,
1020 queue);
1021 spin_unlock_irqrestore(&master->queue_lock, flags);
1022
1023 return next;
1024}
1025EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1026
1027/**
1028 * spi_finalize_current_message() - the current message is complete
1029 * @master: the master to return the message to
1030 *
1031 * Called by the driver to notify the core that the message in the front of the
1032 * queue is complete and can be removed from the queue.
1033 */
1034void spi_finalize_current_message(struct spi_master *master)
1035{
1036 struct spi_message *mesg;
1037 unsigned long flags;
1038 int ret;
1039
1040 spin_lock_irqsave(&master->queue_lock, flags);
1041 mesg = master->cur_msg;
1042 master->cur_msg = NULL;
1043
1044 queue_kthread_work(&master->kworker, &master->pump_messages);
1045 spin_unlock_irqrestore(&master->queue_lock, flags);
1046
1047 spi_unmap_msg(master, mesg);
1048
1049 if (master->cur_msg_prepared && master->unprepare_message) {
1050 ret = master->unprepare_message(master, mesg);
1051 if (ret) {
1052 dev_err(&master->dev,
1053 "failed to unprepare message: %d\n", ret);
1054 }
1055 }
1056 master->cur_msg_prepared = false;
1057
1058 mesg->state = NULL;
1059 if (mesg->complete)
1060 mesg->complete(mesg->context);
1061
1062 trace_spi_message_done(mesg);
1063}
1064EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1065
1066static int spi_start_queue(struct spi_master *master)
1067{
1068 unsigned long flags;
1069
1070 spin_lock_irqsave(&master->queue_lock, flags);
1071
1072 if (master->running || master->busy) {
1073 spin_unlock_irqrestore(&master->queue_lock, flags);
1074 return -EBUSY;
1075 }
1076
1077 master->running = true;
1078 master->cur_msg = NULL;
1079 spin_unlock_irqrestore(&master->queue_lock, flags);
1080
1081 queue_kthread_work(&master->kworker, &master->pump_messages);
1082
1083 return 0;
1084}
1085
1086static int spi_stop_queue(struct spi_master *master)
1087{
1088 unsigned long flags;
1089 unsigned limit = 500;
1090 int ret = 0;
1091
1092 spin_lock_irqsave(&master->queue_lock, flags);
1093
1094 /*
1095 * This is a bit lame, but is optimized for the common execution path.
1096 * A wait_queue on the master->busy could be used, but then the common
1097 * execution path (pump_messages) would be required to call wake_up or
1098 * friends on every SPI message. Do this instead.
1099 */
1100 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1101 spin_unlock_irqrestore(&master->queue_lock, flags);
1102 usleep_range(10000, 11000);
1103 spin_lock_irqsave(&master->queue_lock, flags);
1104 }
1105
1106 if (!list_empty(&master->queue) || master->busy)
1107 ret = -EBUSY;
1108 else
1109 master->running = false;
1110
1111 spin_unlock_irqrestore(&master->queue_lock, flags);
1112
1113 if (ret) {
1114 dev_warn(&master->dev,
1115 "could not stop message queue\n");
1116 return ret;
1117 }
1118 return ret;
1119}
1120
1121static int spi_destroy_queue(struct spi_master *master)
1122{
1123 int ret;
1124
1125 ret = spi_stop_queue(master);
1126
1127 /*
1128 * flush_kthread_worker will block until all work is done.
1129 * If the reason that stop_queue timed out is that the work will never
1130 * finish, then it does no good to call flush/stop thread, so
1131 * return anyway.
1132 */
1133 if (ret) {
1134 dev_err(&master->dev, "problem destroying queue\n");
1135 return ret;
1136 }
1137
1138 flush_kthread_worker(&master->kworker);
1139 kthread_stop(master->kworker_task);
1140
1141 return 0;
1142}
1143
1144/**
1145 * spi_queued_transfer - transfer function for queued transfers
1146 * @spi: spi device which is requesting transfer
1147 * @msg: spi message which is to handled is queued to driver queue
1148 */
1149static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1150{
1151 struct spi_master *master = spi->master;
1152 unsigned long flags;
1153
1154 spin_lock_irqsave(&master->queue_lock, flags);
1155
1156 if (!master->running) {
1157 spin_unlock_irqrestore(&master->queue_lock, flags);
1158 return -ESHUTDOWN;
1159 }
1160 msg->actual_length = 0;
1161 msg->status = -EINPROGRESS;
1162
1163 list_add_tail(&msg->queue, &master->queue);
1164 if (!master->busy)
1165 queue_kthread_work(&master->kworker, &master->pump_messages);
1166
1167 spin_unlock_irqrestore(&master->queue_lock, flags);
1168 return 0;
1169}
1170
1171static int spi_master_initialize_queue(struct spi_master *master)
1172{
1173 int ret;
1174
1175 master->transfer = spi_queued_transfer;
1176 if (!master->transfer_one_message)
1177 master->transfer_one_message = spi_transfer_one_message;
1178
1179 /* Initialize and start queue */
1180 ret = spi_init_queue(master);
1181 if (ret) {
1182 dev_err(&master->dev, "problem initializing queue\n");
1183 goto err_init_queue;
1184 }
1185 master->queued = true;
1186 ret = spi_start_queue(master);
1187 if (ret) {
1188 dev_err(&master->dev, "problem starting queue\n");
1189 goto err_start_queue;
1190 }
1191
1192 return 0;
1193
1194err_start_queue:
1195 spi_destroy_queue(master);
1196err_init_queue:
1197 return ret;
1198}
1199
1200/*-------------------------------------------------------------------------*/
1201
1202#if defined(CONFIG_OF)
1203/**
1204 * of_register_spi_devices() - Register child devices onto the SPI bus
1205 * @master: Pointer to spi_master device
1206 *
1207 * Registers an spi_device for each child node of master node which has a 'reg'
1208 * property.
1209 */
1210static void of_register_spi_devices(struct spi_master *master)
1211{
1212 struct spi_device *spi;
1213 struct device_node *nc;
1214 int rc;
1215 u32 value;
1216
1217 if (!master->dev.of_node)
1218 return;
1219
1220 for_each_available_child_of_node(master->dev.of_node, nc) {
1221 /* Alloc an spi_device */
1222 spi = spi_alloc_device(master);
1223 if (!spi) {
1224 dev_err(&master->dev, "spi_device alloc error for %s\n",
1225 nc->full_name);
1226 spi_dev_put(spi);
1227 continue;
1228 }
1229
1230 /* Select device driver */
1231 if (of_modalias_node(nc, spi->modalias,
1232 sizeof(spi->modalias)) < 0) {
1233 dev_err(&master->dev, "cannot find modalias for %s\n",
1234 nc->full_name);
1235 spi_dev_put(spi);
1236 continue;
1237 }
1238
1239 /* Device address */
1240 rc = of_property_read_u32(nc, "reg", &value);
1241 if (rc) {
1242 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1243 nc->full_name, rc);
1244 spi_dev_put(spi);
1245 continue;
1246 }
1247 spi->chip_select = value;
1248
1249 /* Mode (clock phase/polarity/etc.) */
1250 if (of_find_property(nc, "spi-cpha", NULL))
1251 spi->mode |= SPI_CPHA;
1252 if (of_find_property(nc, "spi-cpol", NULL))
1253 spi->mode |= SPI_CPOL;
1254 if (of_find_property(nc, "spi-cs-high", NULL))
1255 spi->mode |= SPI_CS_HIGH;
1256 if (of_find_property(nc, "spi-3wire", NULL))
1257 spi->mode |= SPI_3WIRE;
1258
1259 /* Device DUAL/QUAD mode */
1260 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1261 switch (value) {
1262 case 1:
1263 break;
1264 case 2:
1265 spi->mode |= SPI_TX_DUAL;
1266 break;
1267 case 4:
1268 spi->mode |= SPI_TX_QUAD;
1269 break;
1270 default:
1271 dev_err(&master->dev,
1272 "spi-tx-bus-width %d not supported\n",
1273 value);
1274 spi_dev_put(spi);
1275 continue;
1276 }
1277 }
1278
1279 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1280 switch (value) {
1281 case 1:
1282 break;
1283 case 2:
1284 spi->mode |= SPI_RX_DUAL;
1285 break;
1286 case 4:
1287 spi->mode |= SPI_RX_QUAD;
1288 break;
1289 default:
1290 dev_err(&master->dev,
1291 "spi-rx-bus-width %d not supported\n",
1292 value);
1293 spi_dev_put(spi);
1294 continue;
1295 }
1296 }
1297
1298 /* Device speed */
1299 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1300 if (rc) {
1301 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1302 nc->full_name, rc);
1303 spi_dev_put(spi);
1304 continue;
1305 }
1306 spi->max_speed_hz = value;
1307
1308 /* IRQ */
1309 spi->irq = irq_of_parse_and_map(nc, 0);
1310
1311 /* Store a pointer to the node in the device structure */
1312 of_node_get(nc);
1313 spi->dev.of_node = nc;
1314
1315 /* Register the new device */
1316 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1317 rc = spi_add_device(spi);
1318 if (rc) {
1319 dev_err(&master->dev, "spi_device register error %s\n",
1320 nc->full_name);
1321 spi_dev_put(spi);
1322 }
1323
1324 }
1325}
1326#else
1327static void of_register_spi_devices(struct spi_master *master) { }
1328#endif
1329
1330#ifdef CONFIG_ACPI
1331static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1332{
1333 struct spi_device *spi = data;
1334
1335 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1336 struct acpi_resource_spi_serialbus *sb;
1337
1338 sb = &ares->data.spi_serial_bus;
1339 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1340 spi->chip_select = sb->device_selection;
1341 spi->max_speed_hz = sb->connection_speed;
1342
1343 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1344 spi->mode |= SPI_CPHA;
1345 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1346 spi->mode |= SPI_CPOL;
1347 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1348 spi->mode |= SPI_CS_HIGH;
1349 }
1350 } else if (spi->irq < 0) {
1351 struct resource r;
1352
1353 if (acpi_dev_resource_interrupt(ares, 0, &r))
1354 spi->irq = r.start;
1355 }
1356
1357 /* Always tell the ACPI core to skip this resource */
1358 return 1;
1359}
1360
1361static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1362 void *data, void **return_value)
1363{
1364 struct spi_master *master = data;
1365 struct list_head resource_list;
1366 struct acpi_device *adev;
1367 struct spi_device *spi;
1368 int ret;
1369
1370 if (acpi_bus_get_device(handle, &adev))
1371 return AE_OK;
1372 if (acpi_bus_get_status(adev) || !adev->status.present)
1373 return AE_OK;
1374
1375 spi = spi_alloc_device(master);
1376 if (!spi) {
1377 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1378 dev_name(&adev->dev));
1379 return AE_NO_MEMORY;
1380 }
1381
1382 ACPI_COMPANION_SET(&spi->dev, adev);
1383 spi->irq = -1;
1384
1385 INIT_LIST_HEAD(&resource_list);
1386 ret = acpi_dev_get_resources(adev, &resource_list,
1387 acpi_spi_add_resource, spi);
1388 acpi_dev_free_resource_list(&resource_list);
1389
1390 if (ret < 0 || !spi->max_speed_hz) {
1391 spi_dev_put(spi);
1392 return AE_OK;
1393 }
1394
1395 adev->power.flags.ignore_parent = true;
1396 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1397 if (spi_add_device(spi)) {
1398 adev->power.flags.ignore_parent = false;
1399 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1400 dev_name(&adev->dev));
1401 spi_dev_put(spi);
1402 }
1403
1404 return AE_OK;
1405}
1406
1407static void acpi_register_spi_devices(struct spi_master *master)
1408{
1409 acpi_status status;
1410 acpi_handle handle;
1411
1412 handle = ACPI_HANDLE(master->dev.parent);
1413 if (!handle)
1414 return;
1415
1416 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1417 acpi_spi_add_device, NULL,
1418 master, NULL);
1419 if (ACPI_FAILURE(status))
1420 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1421}
1422#else
1423static inline void acpi_register_spi_devices(struct spi_master *master) {}
1424#endif /* CONFIG_ACPI */
1425
1426static void spi_master_release(struct device *dev)
1427{
1428 struct spi_master *master;
1429
1430 master = container_of(dev, struct spi_master, dev);
1431 kfree(master);
1432}
1433
1434static struct class spi_master_class = {
1435 .name = "spi_master",
1436 .owner = THIS_MODULE,
1437 .dev_release = spi_master_release,
1438};
1439
1440
1441
1442/**
1443 * spi_alloc_master - allocate SPI master controller
1444 * @dev: the controller, possibly using the platform_bus
1445 * @size: how much zeroed driver-private data to allocate; the pointer to this
1446 * memory is in the driver_data field of the returned device,
1447 * accessible with spi_master_get_devdata().
1448 * Context: can sleep
1449 *
1450 * This call is used only by SPI master controller drivers, which are the
1451 * only ones directly touching chip registers. It's how they allocate
1452 * an spi_master structure, prior to calling spi_register_master().
1453 *
1454 * This must be called from context that can sleep. It returns the SPI
1455 * master structure on success, else NULL.
1456 *
1457 * The caller is responsible for assigning the bus number and initializing
1458 * the master's methods before calling spi_register_master(); and (after errors
1459 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1460 * leak.
1461 */
1462struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1463{
1464 struct spi_master *master;
1465
1466 if (!dev)
1467 return NULL;
1468
1469 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1470 if (!master)
1471 return NULL;
1472
1473 device_initialize(&master->dev);
1474 master->bus_num = -1;
1475 master->num_chipselect = 1;
1476 master->dev.class = &spi_master_class;
1477 master->dev.parent = get_device(dev);
1478 spi_master_set_devdata(master, &master[1]);
1479
1480 return master;
1481}
1482EXPORT_SYMBOL_GPL(spi_alloc_master);
1483
1484#ifdef CONFIG_OF
1485static int of_spi_register_master(struct spi_master *master)
1486{
1487 int nb, i, *cs;
1488 struct device_node *np = master->dev.of_node;
1489
1490 if (!np)
1491 return 0;
1492
1493 nb = of_gpio_named_count(np, "cs-gpios");
1494 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1495
1496 /* Return error only for an incorrectly formed cs-gpios property */
1497 if (nb == 0 || nb == -ENOENT)
1498 return 0;
1499 else if (nb < 0)
1500 return nb;
1501
1502 cs = devm_kzalloc(&master->dev,
1503 sizeof(int) * master->num_chipselect,
1504 GFP_KERNEL);
1505 master->cs_gpios = cs;
1506
1507 if (!master->cs_gpios)
1508 return -ENOMEM;
1509
1510 for (i = 0; i < master->num_chipselect; i++)
1511 cs[i] = -ENOENT;
1512
1513 for (i = 0; i < nb; i++)
1514 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1515
1516 return 0;
1517}
1518#else
1519static int of_spi_register_master(struct spi_master *master)
1520{
1521 return 0;
1522}
1523#endif
1524
1525/**
1526 * spi_register_master - register SPI master controller
1527 * @master: initialized master, originally from spi_alloc_master()
1528 * Context: can sleep
1529 *
1530 * SPI master controllers connect to their drivers using some non-SPI bus,
1531 * such as the platform bus. The final stage of probe() in that code
1532 * includes calling spi_register_master() to hook up to this SPI bus glue.
1533 *
1534 * SPI controllers use board specific (often SOC specific) bus numbers,
1535 * and board-specific addressing for SPI devices combines those numbers
1536 * with chip select numbers. Since SPI does not directly support dynamic
1537 * device identification, boards need configuration tables telling which
1538 * chip is at which address.
1539 *
1540 * This must be called from context that can sleep. It returns zero on
1541 * success, else a negative error code (dropping the master's refcount).
1542 * After a successful return, the caller is responsible for calling
1543 * spi_unregister_master().
1544 */
1545int spi_register_master(struct spi_master *master)
1546{
1547 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1548 struct device *dev = master->dev.parent;
1549 struct boardinfo *bi;
1550 int status = -ENODEV;
1551 int dynamic = 0;
1552
1553 if (!dev)
1554 return -ENODEV;
1555
1556 status = of_spi_register_master(master);
1557 if (status)
1558 return status;
1559
1560 /* even if it's just one always-selected device, there must
1561 * be at least one chipselect
1562 */
1563 if (master->num_chipselect == 0)
1564 return -EINVAL;
1565
1566 if ((master->bus_num < 0) && master->dev.of_node)
1567 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1568
1569 /* convention: dynamically assigned bus IDs count down from the max */
1570 if (master->bus_num < 0) {
1571 /* FIXME switch to an IDR based scheme, something like
1572 * I2C now uses, so we can't run out of "dynamic" IDs
1573 */
1574 master->bus_num = atomic_dec_return(&dyn_bus_id);
1575 dynamic = 1;
1576 }
1577
1578 spin_lock_init(&master->bus_lock_spinlock);
1579 mutex_init(&master->bus_lock_mutex);
1580 master->bus_lock_flag = 0;
1581 init_completion(&master->xfer_completion);
1582 if (!master->max_dma_len)
1583 master->max_dma_len = INT_MAX;
1584
1585 /* register the device, then userspace will see it.
1586 * registration fails if the bus ID is in use.
1587 */
1588 dev_set_name(&master->dev, "spi%u", master->bus_num);
1589 status = device_add(&master->dev);
1590 if (status < 0)
1591 goto done;
1592 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1593 dynamic ? " (dynamic)" : "");
1594
1595 /* If we're using a queued driver, start the queue */
1596 if (master->transfer)
1597 dev_info(dev, "master is unqueued, this is deprecated\n");
1598 else {
1599 status = spi_master_initialize_queue(master);
1600 if (status) {
1601 device_del(&master->dev);
1602 goto done;
1603 }
1604 }
1605
1606 mutex_lock(&board_lock);
1607 list_add_tail(&master->list, &spi_master_list);
1608 list_for_each_entry(bi, &board_list, list)
1609 spi_match_master_to_boardinfo(master, &bi->board_info);
1610 mutex_unlock(&board_lock);
1611
1612 /* Register devices from the device tree and ACPI */
1613 of_register_spi_devices(master);
1614 acpi_register_spi_devices(master);
1615done:
1616 return status;
1617}
1618EXPORT_SYMBOL_GPL(spi_register_master);
1619
1620static void devm_spi_unregister(struct device *dev, void *res)
1621{
1622 spi_unregister_master(*(struct spi_master **)res);
1623}
1624
1625/**
1626 * dev_spi_register_master - register managed SPI master controller
1627 * @dev: device managing SPI master
1628 * @master: initialized master, originally from spi_alloc_master()
1629 * Context: can sleep
1630 *
1631 * Register a SPI device as with spi_register_master() which will
1632 * automatically be unregister
1633 */
1634int devm_spi_register_master(struct device *dev, struct spi_master *master)
1635{
1636 struct spi_master **ptr;
1637 int ret;
1638
1639 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1640 if (!ptr)
1641 return -ENOMEM;
1642
1643 ret = spi_register_master(master);
1644 if (!ret) {
1645 *ptr = master;
1646 devres_add(dev, ptr);
1647 } else {
1648 devres_free(ptr);
1649 }
1650
1651 return ret;
1652}
1653EXPORT_SYMBOL_GPL(devm_spi_register_master);
1654
1655static int __unregister(struct device *dev, void *null)
1656{
1657 spi_unregister_device(to_spi_device(dev));
1658 return 0;
1659}
1660
1661/**
1662 * spi_unregister_master - unregister SPI master controller
1663 * @master: the master being unregistered
1664 * Context: can sleep
1665 *
1666 * This call is used only by SPI master controller drivers, which are the
1667 * only ones directly touching chip registers.
1668 *
1669 * This must be called from context that can sleep.
1670 */
1671void spi_unregister_master(struct spi_master *master)
1672{
1673 int dummy;
1674
1675 if (master->queued) {
1676 if (spi_destroy_queue(master))
1677 dev_err(&master->dev, "queue remove failed\n");
1678 }
1679
1680 mutex_lock(&board_lock);
1681 list_del(&master->list);
1682 mutex_unlock(&board_lock);
1683
1684 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1685 device_unregister(&master->dev);
1686}
1687EXPORT_SYMBOL_GPL(spi_unregister_master);
1688
1689int spi_master_suspend(struct spi_master *master)
1690{
1691 int ret;
1692
1693 /* Basically no-ops for non-queued masters */
1694 if (!master->queued)
1695 return 0;
1696
1697 ret = spi_stop_queue(master);
1698 if (ret)
1699 dev_err(&master->dev, "queue stop failed\n");
1700
1701 return ret;
1702}
1703EXPORT_SYMBOL_GPL(spi_master_suspend);
1704
1705int spi_master_resume(struct spi_master *master)
1706{
1707 int ret;
1708
1709 if (!master->queued)
1710 return 0;
1711
1712 ret = spi_start_queue(master);
1713 if (ret)
1714 dev_err(&master->dev, "queue restart failed\n");
1715
1716 return ret;
1717}
1718EXPORT_SYMBOL_GPL(spi_master_resume);
1719
1720static int __spi_master_match(struct device *dev, const void *data)
1721{
1722 struct spi_master *m;
1723 const u16 *bus_num = data;
1724
1725 m = container_of(dev, struct spi_master, dev);
1726 return m->bus_num == *bus_num;
1727}
1728
1729/**
1730 * spi_busnum_to_master - look up master associated with bus_num
1731 * @bus_num: the master's bus number
1732 * Context: can sleep
1733 *
1734 * This call may be used with devices that are registered after
1735 * arch init time. It returns a refcounted pointer to the relevant
1736 * spi_master (which the caller must release), or NULL if there is
1737 * no such master registered.
1738 */
1739struct spi_master *spi_busnum_to_master(u16 bus_num)
1740{
1741 struct device *dev;
1742 struct spi_master *master = NULL;
1743
1744 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1745 __spi_master_match);
1746 if (dev)
1747 master = container_of(dev, struct spi_master, dev);
1748 /* reference got in class_find_device */
1749 return master;
1750}
1751EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1752
1753
1754/*-------------------------------------------------------------------------*/
1755
1756/* Core methods for SPI master protocol drivers. Some of the
1757 * other core methods are currently defined as inline functions.
1758 */
1759
1760/**
1761 * spi_setup - setup SPI mode and clock rate
1762 * @spi: the device whose settings are being modified
1763 * Context: can sleep, and no requests are queued to the device
1764 *
1765 * SPI protocol drivers may need to update the transfer mode if the
1766 * device doesn't work with its default. They may likewise need
1767 * to update clock rates or word sizes from initial values. This function
1768 * changes those settings, and must be called from a context that can sleep.
1769 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1770 * effect the next time the device is selected and data is transferred to
1771 * or from it. When this function returns, the spi device is deselected.
1772 *
1773 * Note that this call will fail if the protocol driver specifies an option
1774 * that the underlying controller or its driver does not support. For
1775 * example, not all hardware supports wire transfers using nine bit words,
1776 * LSB-first wire encoding, or active-high chipselects.
1777 */
1778int spi_setup(struct spi_device *spi)
1779{
1780 unsigned bad_bits, ugly_bits;
1781 int status = 0;
1782
1783 /* check mode to prevent that DUAL and QUAD set at the same time
1784 */
1785 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1786 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1787 dev_err(&spi->dev,
1788 "setup: can not select dual and quad at the same time\n");
1789 return -EINVAL;
1790 }
1791 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1792 */
1793 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1794 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1795 return -EINVAL;
1796 /* help drivers fail *cleanly* when they need options
1797 * that aren't supported with their current master
1798 */
1799 bad_bits = spi->mode & ~spi->master->mode_bits;
1800 ugly_bits = bad_bits &
1801 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1802 if (ugly_bits) {
1803 dev_warn(&spi->dev,
1804 "setup: ignoring unsupported mode bits %x\n",
1805 ugly_bits);
1806 spi->mode &= ~ugly_bits;
1807 bad_bits &= ~ugly_bits;
1808 }
1809 if (bad_bits) {
1810 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1811 bad_bits);
1812 return -EINVAL;
1813 }
1814
1815 if (!spi->bits_per_word)
1816 spi->bits_per_word = 8;
1817
1818 if (!spi->max_speed_hz)
1819 spi->max_speed_hz = spi->master->max_speed_hz;
1820
1821 if (spi->master->setup)
1822 status = spi->master->setup(spi);
1823
1824 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1825 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1826 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1827 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1828 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1829 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1830 spi->bits_per_word, spi->max_speed_hz,
1831 status);
1832
1833 return status;
1834}
1835EXPORT_SYMBOL_GPL(spi_setup);
1836
1837static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1838{
1839 struct spi_master *master = spi->master;
1840 struct spi_transfer *xfer;
1841 int w_size;
1842
1843 if (list_empty(&message->transfers))
1844 return -EINVAL;
1845
1846 /* Half-duplex links include original MicroWire, and ones with
1847 * only one data pin like SPI_3WIRE (switches direction) or where
1848 * either MOSI or MISO is missing. They can also be caused by
1849 * software limitations.
1850 */
1851 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1852 || (spi->mode & SPI_3WIRE)) {
1853 unsigned flags = master->flags;
1854
1855 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1856 if (xfer->rx_buf && xfer->tx_buf)
1857 return -EINVAL;
1858 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1859 return -EINVAL;
1860 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1861 return -EINVAL;
1862 }
1863 }
1864
1865 /**
1866 * Set transfer bits_per_word and max speed as spi device default if
1867 * it is not set for this transfer.
1868 * Set transfer tx_nbits and rx_nbits as single transfer default
1869 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1870 */
1871 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1872 message->frame_length += xfer->len;
1873 if (!xfer->bits_per_word)
1874 xfer->bits_per_word = spi->bits_per_word;
1875
1876 if (!xfer->speed_hz)
1877 xfer->speed_hz = spi->max_speed_hz;
1878
1879 if (master->max_speed_hz &&
1880 xfer->speed_hz > master->max_speed_hz)
1881 xfer->speed_hz = master->max_speed_hz;
1882
1883 if (master->bits_per_word_mask) {
1884 /* Only 32 bits fit in the mask */
1885 if (xfer->bits_per_word > 32)
1886 return -EINVAL;
1887 if (!(master->bits_per_word_mask &
1888 BIT(xfer->bits_per_word - 1)))
1889 return -EINVAL;
1890 }
1891
1892 /*
1893 * SPI transfer length should be multiple of SPI word size
1894 * where SPI word size should be power-of-two multiple
1895 */
1896 if (xfer->bits_per_word <= 8)
1897 w_size = 1;
1898 else if (xfer->bits_per_word <= 16)
1899 w_size = 2;
1900 else
1901 w_size = 4;
1902
1903 /* No partial transfers accepted */
1904 if (xfer->len % w_size)
1905 return -EINVAL;
1906
1907 if (xfer->speed_hz && master->min_speed_hz &&
1908 xfer->speed_hz < master->min_speed_hz)
1909 return -EINVAL;
1910
1911 if (xfer->tx_buf && !xfer->tx_nbits)
1912 xfer->tx_nbits = SPI_NBITS_SINGLE;
1913 if (xfer->rx_buf && !xfer->rx_nbits)
1914 xfer->rx_nbits = SPI_NBITS_SINGLE;
1915 /* check transfer tx/rx_nbits:
1916 * 1. check the value matches one of single, dual and quad
1917 * 2. check tx/rx_nbits match the mode in spi_device
1918 */
1919 if (xfer->tx_buf) {
1920 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1921 xfer->tx_nbits != SPI_NBITS_DUAL &&
1922 xfer->tx_nbits != SPI_NBITS_QUAD)
1923 return -EINVAL;
1924 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1925 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1926 return -EINVAL;
1927 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1928 !(spi->mode & SPI_TX_QUAD))
1929 return -EINVAL;
1930 }
1931 /* check transfer rx_nbits */
1932 if (xfer->rx_buf) {
1933 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1934 xfer->rx_nbits != SPI_NBITS_DUAL &&
1935 xfer->rx_nbits != SPI_NBITS_QUAD)
1936 return -EINVAL;
1937 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1938 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1939 return -EINVAL;
1940 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1941 !(spi->mode & SPI_RX_QUAD))
1942 return -EINVAL;
1943 }
1944 }
1945
1946 message->status = -EINPROGRESS;
1947
1948 return 0;
1949}
1950
1951static int __spi_async(struct spi_device *spi, struct spi_message *message)
1952{
1953 struct spi_master *master = spi->master;
1954
1955 message->spi = spi;
1956
1957 trace_spi_message_submit(message);
1958
1959 return master->transfer(spi, message);
1960}
1961
1962/**
1963 * spi_async - asynchronous SPI transfer
1964 * @spi: device with which data will be exchanged
1965 * @message: describes the data transfers, including completion callback
1966 * Context: any (irqs may be blocked, etc)
1967 *
1968 * This call may be used in_irq and other contexts which can't sleep,
1969 * as well as from task contexts which can sleep.
1970 *
1971 * The completion callback is invoked in a context which can't sleep.
1972 * Before that invocation, the value of message->status is undefined.
1973 * When the callback is issued, message->status holds either zero (to
1974 * indicate complete success) or a negative error code. After that
1975 * callback returns, the driver which issued the transfer request may
1976 * deallocate the associated memory; it's no longer in use by any SPI
1977 * core or controller driver code.
1978 *
1979 * Note that although all messages to a spi_device are handled in
1980 * FIFO order, messages may go to different devices in other orders.
1981 * Some device might be higher priority, or have various "hard" access
1982 * time requirements, for example.
1983 *
1984 * On detection of any fault during the transfer, processing of
1985 * the entire message is aborted, and the device is deselected.
1986 * Until returning from the associated message completion callback,
1987 * no other spi_message queued to that device will be processed.
1988 * (This rule applies equally to all the synchronous transfer calls,
1989 * which are wrappers around this core asynchronous primitive.)
1990 */
1991int spi_async(struct spi_device *spi, struct spi_message *message)
1992{
1993 struct spi_master *master = spi->master;
1994 int ret;
1995 unsigned long flags;
1996
1997 ret = __spi_validate(spi, message);
1998 if (ret != 0)
1999 return ret;
2000
2001 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2002
2003 if (master->bus_lock_flag)
2004 ret = -EBUSY;
2005 else
2006 ret = __spi_async(spi, message);
2007
2008 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2009
2010 return ret;
2011}
2012EXPORT_SYMBOL_GPL(spi_async);
2013
2014/**
2015 * spi_async_locked - version of spi_async with exclusive bus usage
2016 * @spi: device with which data will be exchanged
2017 * @message: describes the data transfers, including completion callback
2018 * Context: any (irqs may be blocked, etc)
2019 *
2020 * This call may be used in_irq and other contexts which can't sleep,
2021 * as well as from task contexts which can sleep.
2022 *
2023 * The completion callback is invoked in a context which can't sleep.
2024 * Before that invocation, the value of message->status is undefined.
2025 * When the callback is issued, message->status holds either zero (to
2026 * indicate complete success) or a negative error code. After that
2027 * callback returns, the driver which issued the transfer request may
2028 * deallocate the associated memory; it's no longer in use by any SPI
2029 * core or controller driver code.
2030 *
2031 * Note that although all messages to a spi_device are handled in
2032 * FIFO order, messages may go to different devices in other orders.
2033 * Some device might be higher priority, or have various "hard" access
2034 * time requirements, for example.
2035 *
2036 * On detection of any fault during the transfer, processing of
2037 * the entire message is aborted, and the device is deselected.
2038 * Until returning from the associated message completion callback,
2039 * no other spi_message queued to that device will be processed.
2040 * (This rule applies equally to all the synchronous transfer calls,
2041 * which are wrappers around this core asynchronous primitive.)
2042 */
2043int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2044{
2045 struct spi_master *master = spi->master;
2046 int ret;
2047 unsigned long flags;
2048
2049 ret = __spi_validate(spi, message);
2050 if (ret != 0)
2051 return ret;
2052
2053 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2054
2055 ret = __spi_async(spi, message);
2056
2057 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2058
2059 return ret;
2060
2061}
2062EXPORT_SYMBOL_GPL(spi_async_locked);
2063
2064
2065/*-------------------------------------------------------------------------*/
2066
2067/* Utility methods for SPI master protocol drivers, layered on
2068 * top of the core. Some other utility methods are defined as
2069 * inline functions.
2070 */
2071
2072static void spi_complete(void *arg)
2073{
2074 complete(arg);
2075}
2076
2077static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2078 int bus_locked)
2079{
2080 DECLARE_COMPLETION_ONSTACK(done);
2081 int status;
2082 struct spi_master *master = spi->master;
2083
2084 message->complete = spi_complete;
2085 message->context = &done;
2086
2087 if (!bus_locked)
2088 mutex_lock(&master->bus_lock_mutex);
2089
2090 status = spi_async_locked(spi, message);
2091
2092 if (!bus_locked)
2093 mutex_unlock(&master->bus_lock_mutex);
2094
2095 if (status == 0) {
2096 wait_for_completion(&done);
2097 status = message->status;
2098 }
2099 message->context = NULL;
2100 return status;
2101}
2102
2103/**
2104 * spi_sync - blocking/synchronous SPI data transfers
2105 * @spi: device with which data will be exchanged
2106 * @message: describes the data transfers
2107 * Context: can sleep
2108 *
2109 * This call may only be used from a context that may sleep. The sleep
2110 * is non-interruptible, and has no timeout. Low-overhead controller
2111 * drivers may DMA directly into and out of the message buffers.
2112 *
2113 * Note that the SPI device's chip select is active during the message,
2114 * and then is normally disabled between messages. Drivers for some
2115 * frequently-used devices may want to minimize costs of selecting a chip,
2116 * by leaving it selected in anticipation that the next message will go
2117 * to the same chip. (That may increase power usage.)
2118 *
2119 * Also, the caller is guaranteeing that the memory associated with the
2120 * message will not be freed before this call returns.
2121 *
2122 * It returns zero on success, else a negative error code.
2123 */
2124int spi_sync(struct spi_device *spi, struct spi_message *message)
2125{
2126 return __spi_sync(spi, message, 0);
2127}
2128EXPORT_SYMBOL_GPL(spi_sync);
2129
2130/**
2131 * spi_sync_locked - version of spi_sync with exclusive bus usage
2132 * @spi: device with which data will be exchanged
2133 * @message: describes the data transfers
2134 * Context: can sleep
2135 *
2136 * This call may only be used from a context that may sleep. The sleep
2137 * is non-interruptible, and has no timeout. Low-overhead controller
2138 * drivers may DMA directly into and out of the message buffers.
2139 *
2140 * This call should be used by drivers that require exclusive access to the
2141 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2142 * be released by a spi_bus_unlock call when the exclusive access is over.
2143 *
2144 * It returns zero on success, else a negative error code.
2145 */
2146int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2147{
2148 return __spi_sync(spi, message, 1);
2149}
2150EXPORT_SYMBOL_GPL(spi_sync_locked);
2151
2152/**
2153 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2154 * @master: SPI bus master that should be locked for exclusive bus access
2155 * Context: can sleep
2156 *
2157 * This call may only be used from a context that may sleep. The sleep
2158 * is non-interruptible, and has no timeout.
2159 *
2160 * This call should be used by drivers that require exclusive access to the
2161 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2162 * exclusive access is over. Data transfer must be done by spi_sync_locked
2163 * and spi_async_locked calls when the SPI bus lock is held.
2164 *
2165 * It returns zero on success, else a negative error code.
2166 */
2167int spi_bus_lock(struct spi_master *master)
2168{
2169 unsigned long flags;
2170
2171 mutex_lock(&master->bus_lock_mutex);
2172
2173 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2174 master->bus_lock_flag = 1;
2175 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2176
2177 /* mutex remains locked until spi_bus_unlock is called */
2178
2179 return 0;
2180}
2181EXPORT_SYMBOL_GPL(spi_bus_lock);
2182
2183/**
2184 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2185 * @master: SPI bus master that was locked for exclusive bus access
2186 * Context: can sleep
2187 *
2188 * This call may only be used from a context that may sleep. The sleep
2189 * is non-interruptible, and has no timeout.
2190 *
2191 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2192 * call.
2193 *
2194 * It returns zero on success, else a negative error code.
2195 */
2196int spi_bus_unlock(struct spi_master *master)
2197{
2198 master->bus_lock_flag = 0;
2199
2200 mutex_unlock(&master->bus_lock_mutex);
2201
2202 return 0;
2203}
2204EXPORT_SYMBOL_GPL(spi_bus_unlock);
2205
2206/* portable code must never pass more than 32 bytes */
2207#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2208
2209static u8 *buf;
2210
2211/**
2212 * spi_write_then_read - SPI synchronous write followed by read
2213 * @spi: device with which data will be exchanged
2214 * @txbuf: data to be written (need not be dma-safe)
2215 * @n_tx: size of txbuf, in bytes
2216 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2217 * @n_rx: size of rxbuf, in bytes
2218 * Context: can sleep
2219 *
2220 * This performs a half duplex MicroWire style transaction with the
2221 * device, sending txbuf and then reading rxbuf. The return value
2222 * is zero for success, else a negative errno status code.
2223 * This call may only be used from a context that may sleep.
2224 *
2225 * Parameters to this routine are always copied using a small buffer;
2226 * portable code should never use this for more than 32 bytes.
2227 * Performance-sensitive or bulk transfer code should instead use
2228 * spi_{async,sync}() calls with dma-safe buffers.
2229 */
2230int spi_write_then_read(struct spi_device *spi,
2231 const void *txbuf, unsigned n_tx,
2232 void *rxbuf, unsigned n_rx)
2233{
2234 static DEFINE_MUTEX(lock);
2235
2236 int status;
2237 struct spi_message message;
2238 struct spi_transfer x[2];
2239 u8 *local_buf;
2240
2241 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2242 * copying here, (as a pure convenience thing), but we can
2243 * keep heap costs out of the hot path unless someone else is
2244 * using the pre-allocated buffer or the transfer is too large.
2245 */
2246 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2247 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2248 GFP_KERNEL | GFP_DMA);
2249 if (!local_buf)
2250 return -ENOMEM;
2251 } else {
2252 local_buf = buf;
2253 }
2254
2255 spi_message_init(&message);
2256 memset(x, 0, sizeof(x));
2257 if (n_tx) {
2258 x[0].len = n_tx;
2259 spi_message_add_tail(&x[0], &message);
2260 }
2261 if (n_rx) {
2262 x[1].len = n_rx;
2263 spi_message_add_tail(&x[1], &message);
2264 }
2265
2266 memcpy(local_buf, txbuf, n_tx);
2267 x[0].tx_buf = local_buf;
2268 x[1].rx_buf = local_buf + n_tx;
2269
2270 /* do the i/o */
2271 status = spi_sync(spi, &message);
2272 if (status == 0)
2273 memcpy(rxbuf, x[1].rx_buf, n_rx);
2274
2275 if (x[0].tx_buf == buf)
2276 mutex_unlock(&lock);
2277 else
2278 kfree(local_buf);
2279
2280 return status;
2281}
2282EXPORT_SYMBOL_GPL(spi_write_then_read);
2283
2284/*-------------------------------------------------------------------------*/
2285
2286static int __init spi_init(void)
2287{
2288 int status;
2289
2290 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2291 if (!buf) {
2292 status = -ENOMEM;
2293 goto err0;
2294 }
2295
2296 status = bus_register(&spi_bus_type);
2297 if (status < 0)
2298 goto err1;
2299
2300 status = class_register(&spi_master_class);
2301 if (status < 0)
2302 goto err2;
2303 return 0;
2304
2305err2:
2306 bus_unregister(&spi_bus_type);
2307err1:
2308 kfree(buf);
2309 buf = NULL;
2310err0:
2311 return status;
2312}
2313
2314/* board_info is normally registered in arch_initcall(),
2315 * but even essential drivers wait till later
2316 *
2317 * REVISIT only boardinfo really needs static linking. the rest (device and
2318 * driver registration) _could_ be dynamically linked (modular) ... costs
2319 * include needing to have boardinfo data structures be much more public.
2320 */
2321postcore_initcall(spi_init);
2322
1// SPDX-License-Identifier: GPL-2.0-or-later
2// SPI init/core code
3//
4// Copyright (C) 2005 David Brownell
5// Copyright (C) 2008 Secret Lab Technologies Ltd.
6
7#include <linux/kernel.h>
8#include <linux/device.h>
9#include <linux/init.h>
10#include <linux/cache.h>
11#include <linux/dma-mapping.h>
12#include <linux/dmaengine.h>
13#include <linux/mutex.h>
14#include <linux/of_device.h>
15#include <linux/of_irq.h>
16#include <linux/clk/clk-conf.h>
17#include <linux/slab.h>
18#include <linux/mod_devicetable.h>
19#include <linux/spi/spi.h>
20#include <linux/spi/spi-mem.h>
21#include <linux/of_gpio.h>
22#include <linux/gpio/consumer.h>
23#include <linux/pm_runtime.h>
24#include <linux/pm_domain.h>
25#include <linux/property.h>
26#include <linux/export.h>
27#include <linux/sched/rt.h>
28#include <uapi/linux/sched/types.h>
29#include <linux/delay.h>
30#include <linux/kthread.h>
31#include <linux/ioport.h>
32#include <linux/acpi.h>
33#include <linux/highmem.h>
34#include <linux/idr.h>
35#include <linux/platform_data/x86/apple.h>
36
37#define CREATE_TRACE_POINTS
38#include <trace/events/spi.h>
39EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
40EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
41
42#include "internals.h"
43
44static DEFINE_IDR(spi_master_idr);
45
46static void spidev_release(struct device *dev)
47{
48 struct spi_device *spi = to_spi_device(dev);
49
50 /* spi controllers may cleanup for released devices */
51 if (spi->controller->cleanup)
52 spi->controller->cleanup(spi);
53
54 spi_controller_put(spi->controller);
55 kfree(spi->driver_override);
56 kfree(spi);
57}
58
59static ssize_t
60modalias_show(struct device *dev, struct device_attribute *a, char *buf)
61{
62 const struct spi_device *spi = to_spi_device(dev);
63 int len;
64
65 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 if (len != -ENODEV)
67 return len;
68
69 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
70}
71static DEVICE_ATTR_RO(modalias);
72
73static ssize_t driver_override_store(struct device *dev,
74 struct device_attribute *a,
75 const char *buf, size_t count)
76{
77 struct spi_device *spi = to_spi_device(dev);
78 const char *end = memchr(buf, '\n', count);
79 const size_t len = end ? end - buf : count;
80 const char *driver_override, *old;
81
82 /* We need to keep extra room for a newline when displaying value */
83 if (len >= (PAGE_SIZE - 1))
84 return -EINVAL;
85
86 driver_override = kstrndup(buf, len, GFP_KERNEL);
87 if (!driver_override)
88 return -ENOMEM;
89
90 device_lock(dev);
91 old = spi->driver_override;
92 if (len) {
93 spi->driver_override = driver_override;
94 } else {
95 /* Emptry string, disable driver override */
96 spi->driver_override = NULL;
97 kfree(driver_override);
98 }
99 device_unlock(dev);
100 kfree(old);
101
102 return count;
103}
104
105static ssize_t driver_override_show(struct device *dev,
106 struct device_attribute *a, char *buf)
107{
108 const struct spi_device *spi = to_spi_device(dev);
109 ssize_t len;
110
111 device_lock(dev);
112 len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
113 device_unlock(dev);
114 return len;
115}
116static DEVICE_ATTR_RW(driver_override);
117
118#define SPI_STATISTICS_ATTRS(field, file) \
119static ssize_t spi_controller_##field##_show(struct device *dev, \
120 struct device_attribute *attr, \
121 char *buf) \
122{ \
123 struct spi_controller *ctlr = container_of(dev, \
124 struct spi_controller, dev); \
125 return spi_statistics_##field##_show(&ctlr->statistics, buf); \
126} \
127static struct device_attribute dev_attr_spi_controller_##field = { \
128 .attr = { .name = file, .mode = 0444 }, \
129 .show = spi_controller_##field##_show, \
130}; \
131static ssize_t spi_device_##field##_show(struct device *dev, \
132 struct device_attribute *attr, \
133 char *buf) \
134{ \
135 struct spi_device *spi = to_spi_device(dev); \
136 return spi_statistics_##field##_show(&spi->statistics, buf); \
137} \
138static struct device_attribute dev_attr_spi_device_##field = { \
139 .attr = { .name = file, .mode = 0444 }, \
140 .show = spi_device_##field##_show, \
141}
142
143#define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
144static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
145 char *buf) \
146{ \
147 unsigned long flags; \
148 ssize_t len; \
149 spin_lock_irqsave(&stat->lock, flags); \
150 len = sprintf(buf, format_string, stat->field); \
151 spin_unlock_irqrestore(&stat->lock, flags); \
152 return len; \
153} \
154SPI_STATISTICS_ATTRS(name, file)
155
156#define SPI_STATISTICS_SHOW(field, format_string) \
157 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
158 field, format_string)
159
160SPI_STATISTICS_SHOW(messages, "%lu");
161SPI_STATISTICS_SHOW(transfers, "%lu");
162SPI_STATISTICS_SHOW(errors, "%lu");
163SPI_STATISTICS_SHOW(timedout, "%lu");
164
165SPI_STATISTICS_SHOW(spi_sync, "%lu");
166SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
167SPI_STATISTICS_SHOW(spi_async, "%lu");
168
169SPI_STATISTICS_SHOW(bytes, "%llu");
170SPI_STATISTICS_SHOW(bytes_rx, "%llu");
171SPI_STATISTICS_SHOW(bytes_tx, "%llu");
172
173#define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
174 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
175 "transfer_bytes_histo_" number, \
176 transfer_bytes_histo[index], "%lu")
177SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
178SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
179SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
180SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
181SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
182SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
183SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
184SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
185SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
186SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
187SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
188SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
189SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
190SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
191SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
192SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
193SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
194
195SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
196
197static struct attribute *spi_dev_attrs[] = {
198 &dev_attr_modalias.attr,
199 &dev_attr_driver_override.attr,
200 NULL,
201};
202
203static const struct attribute_group spi_dev_group = {
204 .attrs = spi_dev_attrs,
205};
206
207static struct attribute *spi_device_statistics_attrs[] = {
208 &dev_attr_spi_device_messages.attr,
209 &dev_attr_spi_device_transfers.attr,
210 &dev_attr_spi_device_errors.attr,
211 &dev_attr_spi_device_timedout.attr,
212 &dev_attr_spi_device_spi_sync.attr,
213 &dev_attr_spi_device_spi_sync_immediate.attr,
214 &dev_attr_spi_device_spi_async.attr,
215 &dev_attr_spi_device_bytes.attr,
216 &dev_attr_spi_device_bytes_rx.attr,
217 &dev_attr_spi_device_bytes_tx.attr,
218 &dev_attr_spi_device_transfer_bytes_histo0.attr,
219 &dev_attr_spi_device_transfer_bytes_histo1.attr,
220 &dev_attr_spi_device_transfer_bytes_histo2.attr,
221 &dev_attr_spi_device_transfer_bytes_histo3.attr,
222 &dev_attr_spi_device_transfer_bytes_histo4.attr,
223 &dev_attr_spi_device_transfer_bytes_histo5.attr,
224 &dev_attr_spi_device_transfer_bytes_histo6.attr,
225 &dev_attr_spi_device_transfer_bytes_histo7.attr,
226 &dev_attr_spi_device_transfer_bytes_histo8.attr,
227 &dev_attr_spi_device_transfer_bytes_histo9.attr,
228 &dev_attr_spi_device_transfer_bytes_histo10.attr,
229 &dev_attr_spi_device_transfer_bytes_histo11.attr,
230 &dev_attr_spi_device_transfer_bytes_histo12.attr,
231 &dev_attr_spi_device_transfer_bytes_histo13.attr,
232 &dev_attr_spi_device_transfer_bytes_histo14.attr,
233 &dev_attr_spi_device_transfer_bytes_histo15.attr,
234 &dev_attr_spi_device_transfer_bytes_histo16.attr,
235 &dev_attr_spi_device_transfers_split_maxsize.attr,
236 NULL,
237};
238
239static const struct attribute_group spi_device_statistics_group = {
240 .name = "statistics",
241 .attrs = spi_device_statistics_attrs,
242};
243
244static const struct attribute_group *spi_dev_groups[] = {
245 &spi_dev_group,
246 &spi_device_statistics_group,
247 NULL,
248};
249
250static struct attribute *spi_controller_statistics_attrs[] = {
251 &dev_attr_spi_controller_messages.attr,
252 &dev_attr_spi_controller_transfers.attr,
253 &dev_attr_spi_controller_errors.attr,
254 &dev_attr_spi_controller_timedout.attr,
255 &dev_attr_spi_controller_spi_sync.attr,
256 &dev_attr_spi_controller_spi_sync_immediate.attr,
257 &dev_attr_spi_controller_spi_async.attr,
258 &dev_attr_spi_controller_bytes.attr,
259 &dev_attr_spi_controller_bytes_rx.attr,
260 &dev_attr_spi_controller_bytes_tx.attr,
261 &dev_attr_spi_controller_transfer_bytes_histo0.attr,
262 &dev_attr_spi_controller_transfer_bytes_histo1.attr,
263 &dev_attr_spi_controller_transfer_bytes_histo2.attr,
264 &dev_attr_spi_controller_transfer_bytes_histo3.attr,
265 &dev_attr_spi_controller_transfer_bytes_histo4.attr,
266 &dev_attr_spi_controller_transfer_bytes_histo5.attr,
267 &dev_attr_spi_controller_transfer_bytes_histo6.attr,
268 &dev_attr_spi_controller_transfer_bytes_histo7.attr,
269 &dev_attr_spi_controller_transfer_bytes_histo8.attr,
270 &dev_attr_spi_controller_transfer_bytes_histo9.attr,
271 &dev_attr_spi_controller_transfer_bytes_histo10.attr,
272 &dev_attr_spi_controller_transfer_bytes_histo11.attr,
273 &dev_attr_spi_controller_transfer_bytes_histo12.attr,
274 &dev_attr_spi_controller_transfer_bytes_histo13.attr,
275 &dev_attr_spi_controller_transfer_bytes_histo14.attr,
276 &dev_attr_spi_controller_transfer_bytes_histo15.attr,
277 &dev_attr_spi_controller_transfer_bytes_histo16.attr,
278 &dev_attr_spi_controller_transfers_split_maxsize.attr,
279 NULL,
280};
281
282static const struct attribute_group spi_controller_statistics_group = {
283 .name = "statistics",
284 .attrs = spi_controller_statistics_attrs,
285};
286
287static const struct attribute_group *spi_master_groups[] = {
288 &spi_controller_statistics_group,
289 NULL,
290};
291
292void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
293 struct spi_transfer *xfer,
294 struct spi_controller *ctlr)
295{
296 unsigned long flags;
297 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
298
299 if (l2len < 0)
300 l2len = 0;
301
302 spin_lock_irqsave(&stats->lock, flags);
303
304 stats->transfers++;
305 stats->transfer_bytes_histo[l2len]++;
306
307 stats->bytes += xfer->len;
308 if ((xfer->tx_buf) &&
309 (xfer->tx_buf != ctlr->dummy_tx))
310 stats->bytes_tx += xfer->len;
311 if ((xfer->rx_buf) &&
312 (xfer->rx_buf != ctlr->dummy_rx))
313 stats->bytes_rx += xfer->len;
314
315 spin_unlock_irqrestore(&stats->lock, flags);
316}
317EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
318
319/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
320 * and the sysfs version makes coldplug work too.
321 */
322
323static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
324 const struct spi_device *sdev)
325{
326 while (id->name[0]) {
327 if (!strcmp(sdev->modalias, id->name))
328 return id;
329 id++;
330 }
331 return NULL;
332}
333
334const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
335{
336 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
337
338 return spi_match_id(sdrv->id_table, sdev);
339}
340EXPORT_SYMBOL_GPL(spi_get_device_id);
341
342static int spi_match_device(struct device *dev, struct device_driver *drv)
343{
344 const struct spi_device *spi = to_spi_device(dev);
345 const struct spi_driver *sdrv = to_spi_driver(drv);
346
347 /* Check override first, and if set, only use the named driver */
348 if (spi->driver_override)
349 return strcmp(spi->driver_override, drv->name) == 0;
350
351 /* Attempt an OF style match */
352 if (of_driver_match_device(dev, drv))
353 return 1;
354
355 /* Then try ACPI */
356 if (acpi_driver_match_device(dev, drv))
357 return 1;
358
359 if (sdrv->id_table)
360 return !!spi_match_id(sdrv->id_table, spi);
361
362 return strcmp(spi->modalias, drv->name) == 0;
363}
364
365static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
366{
367 const struct spi_device *spi = to_spi_device(dev);
368 int rc;
369
370 rc = acpi_device_uevent_modalias(dev, env);
371 if (rc != -ENODEV)
372 return rc;
373
374 return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
375}
376
377struct bus_type spi_bus_type = {
378 .name = "spi",
379 .dev_groups = spi_dev_groups,
380 .match = spi_match_device,
381 .uevent = spi_uevent,
382};
383EXPORT_SYMBOL_GPL(spi_bus_type);
384
385
386static int spi_drv_probe(struct device *dev)
387{
388 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
389 struct spi_device *spi = to_spi_device(dev);
390 int ret;
391
392 ret = of_clk_set_defaults(dev->of_node, false);
393 if (ret)
394 return ret;
395
396 if (dev->of_node) {
397 spi->irq = of_irq_get(dev->of_node, 0);
398 if (spi->irq == -EPROBE_DEFER)
399 return -EPROBE_DEFER;
400 if (spi->irq < 0)
401 spi->irq = 0;
402 }
403
404 ret = dev_pm_domain_attach(dev, true);
405 if (ret)
406 return ret;
407
408 ret = sdrv->probe(spi);
409 if (ret)
410 dev_pm_domain_detach(dev, true);
411
412 return ret;
413}
414
415static int spi_drv_remove(struct device *dev)
416{
417 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
418 int ret;
419
420 ret = sdrv->remove(to_spi_device(dev));
421 dev_pm_domain_detach(dev, true);
422
423 return ret;
424}
425
426static void spi_drv_shutdown(struct device *dev)
427{
428 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
429
430 sdrv->shutdown(to_spi_device(dev));
431}
432
433/**
434 * __spi_register_driver - register a SPI driver
435 * @owner: owner module of the driver to register
436 * @sdrv: the driver to register
437 * Context: can sleep
438 *
439 * Return: zero on success, else a negative error code.
440 */
441int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
442{
443 sdrv->driver.owner = owner;
444 sdrv->driver.bus = &spi_bus_type;
445 if (sdrv->probe)
446 sdrv->driver.probe = spi_drv_probe;
447 if (sdrv->remove)
448 sdrv->driver.remove = spi_drv_remove;
449 if (sdrv->shutdown)
450 sdrv->driver.shutdown = spi_drv_shutdown;
451 return driver_register(&sdrv->driver);
452}
453EXPORT_SYMBOL_GPL(__spi_register_driver);
454
455/*-------------------------------------------------------------------------*/
456
457/* SPI devices should normally not be created by SPI device drivers; that
458 * would make them board-specific. Similarly with SPI controller drivers.
459 * Device registration normally goes into like arch/.../mach.../board-YYY.c
460 * with other readonly (flashable) information about mainboard devices.
461 */
462
463struct boardinfo {
464 struct list_head list;
465 struct spi_board_info board_info;
466};
467
468static LIST_HEAD(board_list);
469static LIST_HEAD(spi_controller_list);
470
471/*
472 * Used to protect add/del opertion for board_info list and
473 * spi_controller list, and their matching process
474 * also used to protect object of type struct idr
475 */
476static DEFINE_MUTEX(board_lock);
477
478/**
479 * spi_alloc_device - Allocate a new SPI device
480 * @ctlr: Controller to which device is connected
481 * Context: can sleep
482 *
483 * Allows a driver to allocate and initialize a spi_device without
484 * registering it immediately. This allows a driver to directly
485 * fill the spi_device with device parameters before calling
486 * spi_add_device() on it.
487 *
488 * Caller is responsible to call spi_add_device() on the returned
489 * spi_device structure to add it to the SPI controller. If the caller
490 * needs to discard the spi_device without adding it, then it should
491 * call spi_dev_put() on it.
492 *
493 * Return: a pointer to the new device, or NULL.
494 */
495struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
496{
497 struct spi_device *spi;
498
499 if (!spi_controller_get(ctlr))
500 return NULL;
501
502 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
503 if (!spi) {
504 spi_controller_put(ctlr);
505 return NULL;
506 }
507
508 spi->master = spi->controller = ctlr;
509 spi->dev.parent = &ctlr->dev;
510 spi->dev.bus = &spi_bus_type;
511 spi->dev.release = spidev_release;
512 spi->cs_gpio = -ENOENT;
513
514 spin_lock_init(&spi->statistics.lock);
515
516 device_initialize(&spi->dev);
517 return spi;
518}
519EXPORT_SYMBOL_GPL(spi_alloc_device);
520
521static void spi_dev_set_name(struct spi_device *spi)
522{
523 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
524
525 if (adev) {
526 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
527 return;
528 }
529
530 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
531 spi->chip_select);
532}
533
534static int spi_dev_check(struct device *dev, void *data)
535{
536 struct spi_device *spi = to_spi_device(dev);
537 struct spi_device *new_spi = data;
538
539 if (spi->controller == new_spi->controller &&
540 spi->chip_select == new_spi->chip_select)
541 return -EBUSY;
542 return 0;
543}
544
545/**
546 * spi_add_device - Add spi_device allocated with spi_alloc_device
547 * @spi: spi_device to register
548 *
549 * Companion function to spi_alloc_device. Devices allocated with
550 * spi_alloc_device can be added onto the spi bus with this function.
551 *
552 * Return: 0 on success; negative errno on failure
553 */
554int spi_add_device(struct spi_device *spi)
555{
556 static DEFINE_MUTEX(spi_add_lock);
557 struct spi_controller *ctlr = spi->controller;
558 struct device *dev = ctlr->dev.parent;
559 int status;
560
561 /* Chipselects are numbered 0..max; validate. */
562 if (spi->chip_select >= ctlr->num_chipselect) {
563 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
564 ctlr->num_chipselect);
565 return -EINVAL;
566 }
567
568 /* Set the bus ID string */
569 spi_dev_set_name(spi);
570
571 /* We need to make sure there's no other device with this
572 * chipselect **BEFORE** we call setup(), else we'll trash
573 * its configuration. Lock against concurrent add() calls.
574 */
575 mutex_lock(&spi_add_lock);
576
577 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
578 if (status) {
579 dev_err(dev, "chipselect %d already in use\n",
580 spi->chip_select);
581 goto done;
582 }
583
584 /* Descriptors take precedence */
585 if (ctlr->cs_gpiods)
586 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
587 else if (ctlr->cs_gpios)
588 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
589
590 /* Drivers may modify this initial i/o setup, but will
591 * normally rely on the device being setup. Devices
592 * using SPI_CS_HIGH can't coexist well otherwise...
593 */
594 status = spi_setup(spi);
595 if (status < 0) {
596 dev_err(dev, "can't setup %s, status %d\n",
597 dev_name(&spi->dev), status);
598 goto done;
599 }
600
601 /* Device may be bound to an active driver when this returns */
602 status = device_add(&spi->dev);
603 if (status < 0)
604 dev_err(dev, "can't add %s, status %d\n",
605 dev_name(&spi->dev), status);
606 else
607 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
608
609done:
610 mutex_unlock(&spi_add_lock);
611 return status;
612}
613EXPORT_SYMBOL_GPL(spi_add_device);
614
615/**
616 * spi_new_device - instantiate one new SPI device
617 * @ctlr: Controller to which device is connected
618 * @chip: Describes the SPI device
619 * Context: can sleep
620 *
621 * On typical mainboards, this is purely internal; and it's not needed
622 * after board init creates the hard-wired devices. Some development
623 * platforms may not be able to use spi_register_board_info though, and
624 * this is exported so that for example a USB or parport based adapter
625 * driver could add devices (which it would learn about out-of-band).
626 *
627 * Return: the new device, or NULL.
628 */
629struct spi_device *spi_new_device(struct spi_controller *ctlr,
630 struct spi_board_info *chip)
631{
632 struct spi_device *proxy;
633 int status;
634
635 /* NOTE: caller did any chip->bus_num checks necessary.
636 *
637 * Also, unless we change the return value convention to use
638 * error-or-pointer (not NULL-or-pointer), troubleshootability
639 * suggests syslogged diagnostics are best here (ugh).
640 */
641
642 proxy = spi_alloc_device(ctlr);
643 if (!proxy)
644 return NULL;
645
646 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
647
648 proxy->chip_select = chip->chip_select;
649 proxy->max_speed_hz = chip->max_speed_hz;
650 proxy->mode = chip->mode;
651 proxy->irq = chip->irq;
652 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
653 proxy->dev.platform_data = (void *) chip->platform_data;
654 proxy->controller_data = chip->controller_data;
655 proxy->controller_state = NULL;
656
657 if (chip->properties) {
658 status = device_add_properties(&proxy->dev, chip->properties);
659 if (status) {
660 dev_err(&ctlr->dev,
661 "failed to add properties to '%s': %d\n",
662 chip->modalias, status);
663 goto err_dev_put;
664 }
665 }
666
667 status = spi_add_device(proxy);
668 if (status < 0)
669 goto err_remove_props;
670
671 return proxy;
672
673err_remove_props:
674 if (chip->properties)
675 device_remove_properties(&proxy->dev);
676err_dev_put:
677 spi_dev_put(proxy);
678 return NULL;
679}
680EXPORT_SYMBOL_GPL(spi_new_device);
681
682/**
683 * spi_unregister_device - unregister a single SPI device
684 * @spi: spi_device to unregister
685 *
686 * Start making the passed SPI device vanish. Normally this would be handled
687 * by spi_unregister_controller().
688 */
689void spi_unregister_device(struct spi_device *spi)
690{
691 if (!spi)
692 return;
693
694 if (spi->dev.of_node) {
695 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
696 of_node_put(spi->dev.of_node);
697 }
698 if (ACPI_COMPANION(&spi->dev))
699 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
700 device_unregister(&spi->dev);
701}
702EXPORT_SYMBOL_GPL(spi_unregister_device);
703
704static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
705 struct spi_board_info *bi)
706{
707 struct spi_device *dev;
708
709 if (ctlr->bus_num != bi->bus_num)
710 return;
711
712 dev = spi_new_device(ctlr, bi);
713 if (!dev)
714 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
715 bi->modalias);
716}
717
718/**
719 * spi_register_board_info - register SPI devices for a given board
720 * @info: array of chip descriptors
721 * @n: how many descriptors are provided
722 * Context: can sleep
723 *
724 * Board-specific early init code calls this (probably during arch_initcall)
725 * with segments of the SPI device table. Any device nodes are created later,
726 * after the relevant parent SPI controller (bus_num) is defined. We keep
727 * this table of devices forever, so that reloading a controller driver will
728 * not make Linux forget about these hard-wired devices.
729 *
730 * Other code can also call this, e.g. a particular add-on board might provide
731 * SPI devices through its expansion connector, so code initializing that board
732 * would naturally declare its SPI devices.
733 *
734 * The board info passed can safely be __initdata ... but be careful of
735 * any embedded pointers (platform_data, etc), they're copied as-is.
736 * Device properties are deep-copied though.
737 *
738 * Return: zero on success, else a negative error code.
739 */
740int spi_register_board_info(struct spi_board_info const *info, unsigned n)
741{
742 struct boardinfo *bi;
743 int i;
744
745 if (!n)
746 return 0;
747
748 bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
749 if (!bi)
750 return -ENOMEM;
751
752 for (i = 0; i < n; i++, bi++, info++) {
753 struct spi_controller *ctlr;
754
755 memcpy(&bi->board_info, info, sizeof(*info));
756 if (info->properties) {
757 bi->board_info.properties =
758 property_entries_dup(info->properties);
759 if (IS_ERR(bi->board_info.properties))
760 return PTR_ERR(bi->board_info.properties);
761 }
762
763 mutex_lock(&board_lock);
764 list_add_tail(&bi->list, &board_list);
765 list_for_each_entry(ctlr, &spi_controller_list, list)
766 spi_match_controller_to_boardinfo(ctlr,
767 &bi->board_info);
768 mutex_unlock(&board_lock);
769 }
770
771 return 0;
772}
773
774/*-------------------------------------------------------------------------*/
775
776static void spi_set_cs(struct spi_device *spi, bool enable)
777{
778 if (spi->mode & SPI_CS_HIGH)
779 enable = !enable;
780
781 if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
782 /*
783 * Honour the SPI_NO_CS flag and invert the enable line, as
784 * active low is default for SPI. Execution paths that handle
785 * polarity inversion in gpiolib (such as device tree) will
786 * enforce active high using the SPI_CS_HIGH resulting in a
787 * double inversion through the code above.
788 */
789 if (!(spi->mode & SPI_NO_CS)) {
790 if (spi->cs_gpiod)
791 gpiod_set_value_cansleep(spi->cs_gpiod,
792 !enable);
793 else
794 gpio_set_value_cansleep(spi->cs_gpio, !enable);
795 }
796 /* Some SPI masters need both GPIO CS & slave_select */
797 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
798 spi->controller->set_cs)
799 spi->controller->set_cs(spi, !enable);
800 } else if (spi->controller->set_cs) {
801 spi->controller->set_cs(spi, !enable);
802 }
803}
804
805#ifdef CONFIG_HAS_DMA
806int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
807 struct sg_table *sgt, void *buf, size_t len,
808 enum dma_data_direction dir)
809{
810 const bool vmalloced_buf = is_vmalloc_addr(buf);
811 unsigned int max_seg_size = dma_get_max_seg_size(dev);
812#ifdef CONFIG_HIGHMEM
813 const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
814 (unsigned long)buf < (PKMAP_BASE +
815 (LAST_PKMAP * PAGE_SIZE)));
816#else
817 const bool kmap_buf = false;
818#endif
819 int desc_len;
820 int sgs;
821 struct page *vm_page;
822 struct scatterlist *sg;
823 void *sg_buf;
824 size_t min;
825 int i, ret;
826
827 if (vmalloced_buf || kmap_buf) {
828 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
829 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
830 } else if (virt_addr_valid(buf)) {
831 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
832 sgs = DIV_ROUND_UP(len, desc_len);
833 } else {
834 return -EINVAL;
835 }
836
837 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
838 if (ret != 0)
839 return ret;
840
841 sg = &sgt->sgl[0];
842 for (i = 0; i < sgs; i++) {
843
844 if (vmalloced_buf || kmap_buf) {
845 /*
846 * Next scatterlist entry size is the minimum between
847 * the desc_len and the remaining buffer length that
848 * fits in a page.
849 */
850 min = min_t(size_t, desc_len,
851 min_t(size_t, len,
852 PAGE_SIZE - offset_in_page(buf)));
853 if (vmalloced_buf)
854 vm_page = vmalloc_to_page(buf);
855 else
856 vm_page = kmap_to_page(buf);
857 if (!vm_page) {
858 sg_free_table(sgt);
859 return -ENOMEM;
860 }
861 sg_set_page(sg, vm_page,
862 min, offset_in_page(buf));
863 } else {
864 min = min_t(size_t, len, desc_len);
865 sg_buf = buf;
866 sg_set_buf(sg, sg_buf, min);
867 }
868
869 buf += min;
870 len -= min;
871 sg = sg_next(sg);
872 }
873
874 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
875 if (!ret)
876 ret = -ENOMEM;
877 if (ret < 0) {
878 sg_free_table(sgt);
879 return ret;
880 }
881
882 sgt->nents = ret;
883
884 return 0;
885}
886
887void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
888 struct sg_table *sgt, enum dma_data_direction dir)
889{
890 if (sgt->orig_nents) {
891 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
892 sg_free_table(sgt);
893 }
894}
895
896static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
897{
898 struct device *tx_dev, *rx_dev;
899 struct spi_transfer *xfer;
900 int ret;
901
902 if (!ctlr->can_dma)
903 return 0;
904
905 if (ctlr->dma_tx)
906 tx_dev = ctlr->dma_tx->device->dev;
907 else
908 tx_dev = ctlr->dev.parent;
909
910 if (ctlr->dma_rx)
911 rx_dev = ctlr->dma_rx->device->dev;
912 else
913 rx_dev = ctlr->dev.parent;
914
915 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
916 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
917 continue;
918
919 if (xfer->tx_buf != NULL) {
920 ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
921 (void *)xfer->tx_buf, xfer->len,
922 DMA_TO_DEVICE);
923 if (ret != 0)
924 return ret;
925 }
926
927 if (xfer->rx_buf != NULL) {
928 ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
929 xfer->rx_buf, xfer->len,
930 DMA_FROM_DEVICE);
931 if (ret != 0) {
932 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
933 DMA_TO_DEVICE);
934 return ret;
935 }
936 }
937 }
938
939 ctlr->cur_msg_mapped = true;
940
941 return 0;
942}
943
944static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
945{
946 struct spi_transfer *xfer;
947 struct device *tx_dev, *rx_dev;
948
949 if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
950 return 0;
951
952 if (ctlr->dma_tx)
953 tx_dev = ctlr->dma_tx->device->dev;
954 else
955 tx_dev = ctlr->dev.parent;
956
957 if (ctlr->dma_rx)
958 rx_dev = ctlr->dma_rx->device->dev;
959 else
960 rx_dev = ctlr->dev.parent;
961
962 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
963 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
964 continue;
965
966 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
967 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
968 }
969
970 return 0;
971}
972#else /* !CONFIG_HAS_DMA */
973static inline int __spi_map_msg(struct spi_controller *ctlr,
974 struct spi_message *msg)
975{
976 return 0;
977}
978
979static inline int __spi_unmap_msg(struct spi_controller *ctlr,
980 struct spi_message *msg)
981{
982 return 0;
983}
984#endif /* !CONFIG_HAS_DMA */
985
986static inline int spi_unmap_msg(struct spi_controller *ctlr,
987 struct spi_message *msg)
988{
989 struct spi_transfer *xfer;
990
991 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
992 /*
993 * Restore the original value of tx_buf or rx_buf if they are
994 * NULL.
995 */
996 if (xfer->tx_buf == ctlr->dummy_tx)
997 xfer->tx_buf = NULL;
998 if (xfer->rx_buf == ctlr->dummy_rx)
999 xfer->rx_buf = NULL;
1000 }
1001
1002 return __spi_unmap_msg(ctlr, msg);
1003}
1004
1005static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1006{
1007 struct spi_transfer *xfer;
1008 void *tmp;
1009 unsigned int max_tx, max_rx;
1010
1011 if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1012 max_tx = 0;
1013 max_rx = 0;
1014
1015 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1016 if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1017 !xfer->tx_buf)
1018 max_tx = max(xfer->len, max_tx);
1019 if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1020 !xfer->rx_buf)
1021 max_rx = max(xfer->len, max_rx);
1022 }
1023
1024 if (max_tx) {
1025 tmp = krealloc(ctlr->dummy_tx, max_tx,
1026 GFP_KERNEL | GFP_DMA);
1027 if (!tmp)
1028 return -ENOMEM;
1029 ctlr->dummy_tx = tmp;
1030 memset(tmp, 0, max_tx);
1031 }
1032
1033 if (max_rx) {
1034 tmp = krealloc(ctlr->dummy_rx, max_rx,
1035 GFP_KERNEL | GFP_DMA);
1036 if (!tmp)
1037 return -ENOMEM;
1038 ctlr->dummy_rx = tmp;
1039 }
1040
1041 if (max_tx || max_rx) {
1042 list_for_each_entry(xfer, &msg->transfers,
1043 transfer_list) {
1044 if (!xfer->len)
1045 continue;
1046 if (!xfer->tx_buf)
1047 xfer->tx_buf = ctlr->dummy_tx;
1048 if (!xfer->rx_buf)
1049 xfer->rx_buf = ctlr->dummy_rx;
1050 }
1051 }
1052 }
1053
1054 return __spi_map_msg(ctlr, msg);
1055}
1056
1057static int spi_transfer_wait(struct spi_controller *ctlr,
1058 struct spi_message *msg,
1059 struct spi_transfer *xfer)
1060{
1061 struct spi_statistics *statm = &ctlr->statistics;
1062 struct spi_statistics *stats = &msg->spi->statistics;
1063 unsigned long long ms = 1;
1064
1065 if (spi_controller_is_slave(ctlr)) {
1066 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1067 dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1068 return -EINTR;
1069 }
1070 } else {
1071 ms = 8LL * 1000LL * xfer->len;
1072 do_div(ms, xfer->speed_hz);
1073 ms += ms + 200; /* some tolerance */
1074
1075 if (ms > UINT_MAX)
1076 ms = UINT_MAX;
1077
1078 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1079 msecs_to_jiffies(ms));
1080
1081 if (ms == 0) {
1082 SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1083 SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1084 dev_err(&msg->spi->dev,
1085 "SPI transfer timed out\n");
1086 return -ETIMEDOUT;
1087 }
1088 }
1089
1090 return 0;
1091}
1092
1093static void _spi_transfer_delay_ns(u32 ns)
1094{
1095 if (!ns)
1096 return;
1097 if (ns <= 1000) {
1098 ndelay(ns);
1099 } else {
1100 u32 us = DIV_ROUND_UP(ns, 1000);
1101
1102 if (us <= 10)
1103 udelay(us);
1104 else
1105 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1106 }
1107}
1108
1109static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1110 struct spi_transfer *xfer)
1111{
1112 u32 delay = xfer->cs_change_delay;
1113 u32 unit = xfer->cs_change_delay_unit;
1114 u32 hz;
1115
1116 /* return early on "fast" mode - for everything but USECS */
1117 if (!delay && unit != SPI_DELAY_UNIT_USECS)
1118 return;
1119
1120 switch (unit) {
1121 case SPI_DELAY_UNIT_USECS:
1122 /* for compatibility use default of 10us */
1123 if (!delay)
1124 delay = 10000;
1125 else
1126 delay *= 1000;
1127 break;
1128 case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1129 break;
1130 case SPI_DELAY_UNIT_SCK:
1131 /* if there is no effective speed know, then approximate
1132 * by underestimating with half the requested hz
1133 */
1134 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1135 delay *= DIV_ROUND_UP(1000000000, hz);
1136 break;
1137 default:
1138 dev_err_once(&msg->spi->dev,
1139 "Use of unsupported delay unit %i, using default of 10us\n",
1140 xfer->cs_change_delay_unit);
1141 delay = 10000;
1142 }
1143 /* now sleep for the requested amount of time */
1144 _spi_transfer_delay_ns(delay);
1145}
1146
1147/*
1148 * spi_transfer_one_message - Default implementation of transfer_one_message()
1149 *
1150 * This is a standard implementation of transfer_one_message() for
1151 * drivers which implement a transfer_one() operation. It provides
1152 * standard handling of delays and chip select management.
1153 */
1154static int spi_transfer_one_message(struct spi_controller *ctlr,
1155 struct spi_message *msg)
1156{
1157 struct spi_transfer *xfer;
1158 bool keep_cs = false;
1159 int ret = 0;
1160 struct spi_statistics *statm = &ctlr->statistics;
1161 struct spi_statistics *stats = &msg->spi->statistics;
1162
1163 spi_set_cs(msg->spi, true);
1164
1165 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1166 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1167
1168 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1169 trace_spi_transfer_start(msg, xfer);
1170
1171 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1172 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1173
1174 if (xfer->tx_buf || xfer->rx_buf) {
1175 reinit_completion(&ctlr->xfer_completion);
1176
1177 ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1178 if (ret < 0) {
1179 SPI_STATISTICS_INCREMENT_FIELD(statm,
1180 errors);
1181 SPI_STATISTICS_INCREMENT_FIELD(stats,
1182 errors);
1183 dev_err(&msg->spi->dev,
1184 "SPI transfer failed: %d\n", ret);
1185 goto out;
1186 }
1187
1188 if (ret > 0) {
1189 ret = spi_transfer_wait(ctlr, msg, xfer);
1190 if (ret < 0)
1191 msg->status = ret;
1192 }
1193 } else {
1194 if (xfer->len)
1195 dev_err(&msg->spi->dev,
1196 "Bufferless transfer has length %u\n",
1197 xfer->len);
1198 }
1199
1200 trace_spi_transfer_stop(msg, xfer);
1201
1202 if (msg->status != -EINPROGRESS)
1203 goto out;
1204
1205 if (xfer->delay_usecs)
1206 _spi_transfer_delay_ns(xfer->delay_usecs * 1000);
1207
1208 if (xfer->cs_change) {
1209 if (list_is_last(&xfer->transfer_list,
1210 &msg->transfers)) {
1211 keep_cs = true;
1212 } else {
1213 spi_set_cs(msg->spi, false);
1214 _spi_transfer_cs_change_delay(msg, xfer);
1215 spi_set_cs(msg->spi, true);
1216 }
1217 }
1218
1219 msg->actual_length += xfer->len;
1220 }
1221
1222out:
1223 if (ret != 0 || !keep_cs)
1224 spi_set_cs(msg->spi, false);
1225
1226 if (msg->status == -EINPROGRESS)
1227 msg->status = ret;
1228
1229 if (msg->status && ctlr->handle_err)
1230 ctlr->handle_err(ctlr, msg);
1231
1232 spi_res_release(ctlr, msg);
1233
1234 spi_finalize_current_message(ctlr);
1235
1236 return ret;
1237}
1238
1239/**
1240 * spi_finalize_current_transfer - report completion of a transfer
1241 * @ctlr: the controller reporting completion
1242 *
1243 * Called by SPI drivers using the core transfer_one_message()
1244 * implementation to notify it that the current interrupt driven
1245 * transfer has finished and the next one may be scheduled.
1246 */
1247void spi_finalize_current_transfer(struct spi_controller *ctlr)
1248{
1249 complete(&ctlr->xfer_completion);
1250}
1251EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1252
1253/**
1254 * __spi_pump_messages - function which processes spi message queue
1255 * @ctlr: controller to process queue for
1256 * @in_kthread: true if we are in the context of the message pump thread
1257 *
1258 * This function checks if there is any spi message in the queue that
1259 * needs processing and if so call out to the driver to initialize hardware
1260 * and transfer each message.
1261 *
1262 * Note that it is called both from the kthread itself and also from
1263 * inside spi_sync(); the queue extraction handling at the top of the
1264 * function should deal with this safely.
1265 */
1266static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1267{
1268 struct spi_message *msg;
1269 bool was_busy = false;
1270 unsigned long flags;
1271 int ret;
1272
1273 /* Lock queue */
1274 spin_lock_irqsave(&ctlr->queue_lock, flags);
1275
1276 /* Make sure we are not already running a message */
1277 if (ctlr->cur_msg) {
1278 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1279 return;
1280 }
1281
1282 /* If another context is idling the device then defer */
1283 if (ctlr->idling) {
1284 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1285 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1286 return;
1287 }
1288
1289 /* Check if the queue is idle */
1290 if (list_empty(&ctlr->queue) || !ctlr->running) {
1291 if (!ctlr->busy) {
1292 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1293 return;
1294 }
1295
1296 /* Only do teardown in the thread */
1297 if (!in_kthread) {
1298 kthread_queue_work(&ctlr->kworker,
1299 &ctlr->pump_messages);
1300 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1301 return;
1302 }
1303
1304 ctlr->busy = false;
1305 ctlr->idling = true;
1306 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1307
1308 kfree(ctlr->dummy_rx);
1309 ctlr->dummy_rx = NULL;
1310 kfree(ctlr->dummy_tx);
1311 ctlr->dummy_tx = NULL;
1312 if (ctlr->unprepare_transfer_hardware &&
1313 ctlr->unprepare_transfer_hardware(ctlr))
1314 dev_err(&ctlr->dev,
1315 "failed to unprepare transfer hardware\n");
1316 if (ctlr->auto_runtime_pm) {
1317 pm_runtime_mark_last_busy(ctlr->dev.parent);
1318 pm_runtime_put_autosuspend(ctlr->dev.parent);
1319 }
1320 trace_spi_controller_idle(ctlr);
1321
1322 spin_lock_irqsave(&ctlr->queue_lock, flags);
1323 ctlr->idling = false;
1324 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1325 return;
1326 }
1327
1328 /* Extract head of queue */
1329 msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1330 ctlr->cur_msg = msg;
1331
1332 list_del_init(&msg->queue);
1333 if (ctlr->busy)
1334 was_busy = true;
1335 else
1336 ctlr->busy = true;
1337 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1338
1339 mutex_lock(&ctlr->io_mutex);
1340
1341 if (!was_busy && ctlr->auto_runtime_pm) {
1342 ret = pm_runtime_get_sync(ctlr->dev.parent);
1343 if (ret < 0) {
1344 pm_runtime_put_noidle(ctlr->dev.parent);
1345 dev_err(&ctlr->dev, "Failed to power device: %d\n",
1346 ret);
1347 mutex_unlock(&ctlr->io_mutex);
1348 return;
1349 }
1350 }
1351
1352 if (!was_busy)
1353 trace_spi_controller_busy(ctlr);
1354
1355 if (!was_busy && ctlr->prepare_transfer_hardware) {
1356 ret = ctlr->prepare_transfer_hardware(ctlr);
1357 if (ret) {
1358 dev_err(&ctlr->dev,
1359 "failed to prepare transfer hardware: %d\n",
1360 ret);
1361
1362 if (ctlr->auto_runtime_pm)
1363 pm_runtime_put(ctlr->dev.parent);
1364
1365 msg->status = ret;
1366 spi_finalize_current_message(ctlr);
1367
1368 mutex_unlock(&ctlr->io_mutex);
1369 return;
1370 }
1371 }
1372
1373 trace_spi_message_start(msg);
1374
1375 if (ctlr->prepare_message) {
1376 ret = ctlr->prepare_message(ctlr, msg);
1377 if (ret) {
1378 dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1379 ret);
1380 msg->status = ret;
1381 spi_finalize_current_message(ctlr);
1382 goto out;
1383 }
1384 ctlr->cur_msg_prepared = true;
1385 }
1386
1387 ret = spi_map_msg(ctlr, msg);
1388 if (ret) {
1389 msg->status = ret;
1390 spi_finalize_current_message(ctlr);
1391 goto out;
1392 }
1393
1394 ret = ctlr->transfer_one_message(ctlr, msg);
1395 if (ret) {
1396 dev_err(&ctlr->dev,
1397 "failed to transfer one message from queue\n");
1398 goto out;
1399 }
1400
1401out:
1402 mutex_unlock(&ctlr->io_mutex);
1403
1404 /* Prod the scheduler in case transfer_one() was busy waiting */
1405 if (!ret)
1406 cond_resched();
1407}
1408
1409/**
1410 * spi_pump_messages - kthread work function which processes spi message queue
1411 * @work: pointer to kthread work struct contained in the controller struct
1412 */
1413static void spi_pump_messages(struct kthread_work *work)
1414{
1415 struct spi_controller *ctlr =
1416 container_of(work, struct spi_controller, pump_messages);
1417
1418 __spi_pump_messages(ctlr, true);
1419}
1420
1421/**
1422 * spi_set_thread_rt - set the controller to pump at realtime priority
1423 * @ctlr: controller to boost priority of
1424 *
1425 * This can be called because the controller requested realtime priority
1426 * (by setting the ->rt value before calling spi_register_controller()) or
1427 * because a device on the bus said that its transfers needed realtime
1428 * priority.
1429 *
1430 * NOTE: at the moment if any device on a bus says it needs realtime then
1431 * the thread will be at realtime priority for all transfers on that
1432 * controller. If this eventually becomes a problem we may see if we can
1433 * find a way to boost the priority only temporarily during relevant
1434 * transfers.
1435 */
1436static void spi_set_thread_rt(struct spi_controller *ctlr)
1437{
1438 struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
1439
1440 dev_info(&ctlr->dev,
1441 "will run message pump with realtime priority\n");
1442 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, ¶m);
1443}
1444
1445static int spi_init_queue(struct spi_controller *ctlr)
1446{
1447 ctlr->running = false;
1448 ctlr->busy = false;
1449
1450 kthread_init_worker(&ctlr->kworker);
1451 ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1452 "%s", dev_name(&ctlr->dev));
1453 if (IS_ERR(ctlr->kworker_task)) {
1454 dev_err(&ctlr->dev, "failed to create message pump task\n");
1455 return PTR_ERR(ctlr->kworker_task);
1456 }
1457 kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1458
1459 /*
1460 * Controller config will indicate if this controller should run the
1461 * message pump with high (realtime) priority to reduce the transfer
1462 * latency on the bus by minimising the delay between a transfer
1463 * request and the scheduling of the message pump thread. Without this
1464 * setting the message pump thread will remain at default priority.
1465 */
1466 if (ctlr->rt)
1467 spi_set_thread_rt(ctlr);
1468
1469 return 0;
1470}
1471
1472/**
1473 * spi_get_next_queued_message() - called by driver to check for queued
1474 * messages
1475 * @ctlr: the controller to check for queued messages
1476 *
1477 * If there are more messages in the queue, the next message is returned from
1478 * this call.
1479 *
1480 * Return: the next message in the queue, else NULL if the queue is empty.
1481 */
1482struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1483{
1484 struct spi_message *next;
1485 unsigned long flags;
1486
1487 /* get a pointer to the next message, if any */
1488 spin_lock_irqsave(&ctlr->queue_lock, flags);
1489 next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1490 queue);
1491 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1492
1493 return next;
1494}
1495EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1496
1497/**
1498 * spi_finalize_current_message() - the current message is complete
1499 * @ctlr: the controller to return the message to
1500 *
1501 * Called by the driver to notify the core that the message in the front of the
1502 * queue is complete and can be removed from the queue.
1503 */
1504void spi_finalize_current_message(struct spi_controller *ctlr)
1505{
1506 struct spi_message *mesg;
1507 unsigned long flags;
1508 int ret;
1509
1510 spin_lock_irqsave(&ctlr->queue_lock, flags);
1511 mesg = ctlr->cur_msg;
1512 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1513
1514 spi_unmap_msg(ctlr, mesg);
1515
1516 if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1517 ret = ctlr->unprepare_message(ctlr, mesg);
1518 if (ret) {
1519 dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1520 ret);
1521 }
1522 }
1523
1524 spin_lock_irqsave(&ctlr->queue_lock, flags);
1525 ctlr->cur_msg = NULL;
1526 ctlr->cur_msg_prepared = false;
1527 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1528 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1529
1530 trace_spi_message_done(mesg);
1531
1532 mesg->state = NULL;
1533 if (mesg->complete)
1534 mesg->complete(mesg->context);
1535}
1536EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1537
1538static int spi_start_queue(struct spi_controller *ctlr)
1539{
1540 unsigned long flags;
1541
1542 spin_lock_irqsave(&ctlr->queue_lock, flags);
1543
1544 if (ctlr->running || ctlr->busy) {
1545 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1546 return -EBUSY;
1547 }
1548
1549 ctlr->running = true;
1550 ctlr->cur_msg = NULL;
1551 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1552
1553 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1554
1555 return 0;
1556}
1557
1558static int spi_stop_queue(struct spi_controller *ctlr)
1559{
1560 unsigned long flags;
1561 unsigned limit = 500;
1562 int ret = 0;
1563
1564 spin_lock_irqsave(&ctlr->queue_lock, flags);
1565
1566 /*
1567 * This is a bit lame, but is optimized for the common execution path.
1568 * A wait_queue on the ctlr->busy could be used, but then the common
1569 * execution path (pump_messages) would be required to call wake_up or
1570 * friends on every SPI message. Do this instead.
1571 */
1572 while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1573 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1574 usleep_range(10000, 11000);
1575 spin_lock_irqsave(&ctlr->queue_lock, flags);
1576 }
1577
1578 if (!list_empty(&ctlr->queue) || ctlr->busy)
1579 ret = -EBUSY;
1580 else
1581 ctlr->running = false;
1582
1583 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1584
1585 if (ret) {
1586 dev_warn(&ctlr->dev, "could not stop message queue\n");
1587 return ret;
1588 }
1589 return ret;
1590}
1591
1592static int spi_destroy_queue(struct spi_controller *ctlr)
1593{
1594 int ret;
1595
1596 ret = spi_stop_queue(ctlr);
1597
1598 /*
1599 * kthread_flush_worker will block until all work is done.
1600 * If the reason that stop_queue timed out is that the work will never
1601 * finish, then it does no good to call flush/stop thread, so
1602 * return anyway.
1603 */
1604 if (ret) {
1605 dev_err(&ctlr->dev, "problem destroying queue\n");
1606 return ret;
1607 }
1608
1609 kthread_flush_worker(&ctlr->kworker);
1610 kthread_stop(ctlr->kworker_task);
1611
1612 return 0;
1613}
1614
1615static int __spi_queued_transfer(struct spi_device *spi,
1616 struct spi_message *msg,
1617 bool need_pump)
1618{
1619 struct spi_controller *ctlr = spi->controller;
1620 unsigned long flags;
1621
1622 spin_lock_irqsave(&ctlr->queue_lock, flags);
1623
1624 if (!ctlr->running) {
1625 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1626 return -ESHUTDOWN;
1627 }
1628 msg->actual_length = 0;
1629 msg->status = -EINPROGRESS;
1630
1631 list_add_tail(&msg->queue, &ctlr->queue);
1632 if (!ctlr->busy && need_pump)
1633 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1634
1635 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1636 return 0;
1637}
1638
1639/**
1640 * spi_queued_transfer - transfer function for queued transfers
1641 * @spi: spi device which is requesting transfer
1642 * @msg: spi message which is to handled is queued to driver queue
1643 *
1644 * Return: zero on success, else a negative error code.
1645 */
1646static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1647{
1648 return __spi_queued_transfer(spi, msg, true);
1649}
1650
1651static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1652{
1653 int ret;
1654
1655 ctlr->transfer = spi_queued_transfer;
1656 if (!ctlr->transfer_one_message)
1657 ctlr->transfer_one_message = spi_transfer_one_message;
1658
1659 /* Initialize and start queue */
1660 ret = spi_init_queue(ctlr);
1661 if (ret) {
1662 dev_err(&ctlr->dev, "problem initializing queue\n");
1663 goto err_init_queue;
1664 }
1665 ctlr->queued = true;
1666 ret = spi_start_queue(ctlr);
1667 if (ret) {
1668 dev_err(&ctlr->dev, "problem starting queue\n");
1669 goto err_start_queue;
1670 }
1671
1672 return 0;
1673
1674err_start_queue:
1675 spi_destroy_queue(ctlr);
1676err_init_queue:
1677 return ret;
1678}
1679
1680/**
1681 * spi_flush_queue - Send all pending messages in the queue from the callers'
1682 * context
1683 * @ctlr: controller to process queue for
1684 *
1685 * This should be used when one wants to ensure all pending messages have been
1686 * sent before doing something. Is used by the spi-mem code to make sure SPI
1687 * memory operations do not preempt regular SPI transfers that have been queued
1688 * before the spi-mem operation.
1689 */
1690void spi_flush_queue(struct spi_controller *ctlr)
1691{
1692 if (ctlr->transfer == spi_queued_transfer)
1693 __spi_pump_messages(ctlr, false);
1694}
1695
1696/*-------------------------------------------------------------------------*/
1697
1698#if defined(CONFIG_OF)
1699static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1700 struct device_node *nc)
1701{
1702 u32 value;
1703 int rc;
1704
1705 /* Mode (clock phase/polarity/etc.) */
1706 if (of_property_read_bool(nc, "spi-cpha"))
1707 spi->mode |= SPI_CPHA;
1708 if (of_property_read_bool(nc, "spi-cpol"))
1709 spi->mode |= SPI_CPOL;
1710 if (of_property_read_bool(nc, "spi-3wire"))
1711 spi->mode |= SPI_3WIRE;
1712 if (of_property_read_bool(nc, "spi-lsb-first"))
1713 spi->mode |= SPI_LSB_FIRST;
1714
1715 /*
1716 * For descriptors associated with the device, polarity inversion is
1717 * handled in the gpiolib, so all chip selects are "active high" in
1718 * the logical sense, the gpiolib will invert the line if need be.
1719 */
1720 if (ctlr->use_gpio_descriptors)
1721 spi->mode |= SPI_CS_HIGH;
1722 else if (of_property_read_bool(nc, "spi-cs-high"))
1723 spi->mode |= SPI_CS_HIGH;
1724
1725 /* Device DUAL/QUAD mode */
1726 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1727 switch (value) {
1728 case 1:
1729 break;
1730 case 2:
1731 spi->mode |= SPI_TX_DUAL;
1732 break;
1733 case 4:
1734 spi->mode |= SPI_TX_QUAD;
1735 break;
1736 case 8:
1737 spi->mode |= SPI_TX_OCTAL;
1738 break;
1739 default:
1740 dev_warn(&ctlr->dev,
1741 "spi-tx-bus-width %d not supported\n",
1742 value);
1743 break;
1744 }
1745 }
1746
1747 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1748 switch (value) {
1749 case 1:
1750 break;
1751 case 2:
1752 spi->mode |= SPI_RX_DUAL;
1753 break;
1754 case 4:
1755 spi->mode |= SPI_RX_QUAD;
1756 break;
1757 case 8:
1758 spi->mode |= SPI_RX_OCTAL;
1759 break;
1760 default:
1761 dev_warn(&ctlr->dev,
1762 "spi-rx-bus-width %d not supported\n",
1763 value);
1764 break;
1765 }
1766 }
1767
1768 if (spi_controller_is_slave(ctlr)) {
1769 if (!of_node_name_eq(nc, "slave")) {
1770 dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1771 nc);
1772 return -EINVAL;
1773 }
1774 return 0;
1775 }
1776
1777 /* Device address */
1778 rc = of_property_read_u32(nc, "reg", &value);
1779 if (rc) {
1780 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1781 nc, rc);
1782 return rc;
1783 }
1784 spi->chip_select = value;
1785
1786 /* Device speed */
1787 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1788 if (rc) {
1789 dev_err(&ctlr->dev,
1790 "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1791 return rc;
1792 }
1793 spi->max_speed_hz = value;
1794
1795 return 0;
1796}
1797
1798static struct spi_device *
1799of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1800{
1801 struct spi_device *spi;
1802 int rc;
1803
1804 /* Alloc an spi_device */
1805 spi = spi_alloc_device(ctlr);
1806 if (!spi) {
1807 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1808 rc = -ENOMEM;
1809 goto err_out;
1810 }
1811
1812 /* Select device driver */
1813 rc = of_modalias_node(nc, spi->modalias,
1814 sizeof(spi->modalias));
1815 if (rc < 0) {
1816 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1817 goto err_out;
1818 }
1819
1820 rc = of_spi_parse_dt(ctlr, spi, nc);
1821 if (rc)
1822 goto err_out;
1823
1824 /* Store a pointer to the node in the device structure */
1825 of_node_get(nc);
1826 spi->dev.of_node = nc;
1827
1828 /* Register the new device */
1829 rc = spi_add_device(spi);
1830 if (rc) {
1831 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1832 goto err_of_node_put;
1833 }
1834
1835 return spi;
1836
1837err_of_node_put:
1838 of_node_put(nc);
1839err_out:
1840 spi_dev_put(spi);
1841 return ERR_PTR(rc);
1842}
1843
1844/**
1845 * of_register_spi_devices() - Register child devices onto the SPI bus
1846 * @ctlr: Pointer to spi_controller device
1847 *
1848 * Registers an spi_device for each child node of controller node which
1849 * represents a valid SPI slave.
1850 */
1851static void of_register_spi_devices(struct spi_controller *ctlr)
1852{
1853 struct spi_device *spi;
1854 struct device_node *nc;
1855
1856 if (!ctlr->dev.of_node)
1857 return;
1858
1859 for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1860 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1861 continue;
1862 spi = of_register_spi_device(ctlr, nc);
1863 if (IS_ERR(spi)) {
1864 dev_warn(&ctlr->dev,
1865 "Failed to create SPI device for %pOF\n", nc);
1866 of_node_clear_flag(nc, OF_POPULATED);
1867 }
1868 }
1869}
1870#else
1871static void of_register_spi_devices(struct spi_controller *ctlr) { }
1872#endif
1873
1874#ifdef CONFIG_ACPI
1875struct acpi_spi_lookup {
1876 struct spi_controller *ctlr;
1877 u32 max_speed_hz;
1878 u32 mode;
1879 int irq;
1880 u8 bits_per_word;
1881 u8 chip_select;
1882};
1883
1884static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
1885 struct acpi_spi_lookup *lookup)
1886{
1887 const union acpi_object *obj;
1888
1889 if (!x86_apple_machine)
1890 return;
1891
1892 if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1893 && obj->buffer.length >= 4)
1894 lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1895
1896 if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1897 && obj->buffer.length == 8)
1898 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
1899
1900 if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1901 && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1902 lookup->mode |= SPI_LSB_FIRST;
1903
1904 if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1905 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
1906 lookup->mode |= SPI_CPOL;
1907
1908 if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1909 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
1910 lookup->mode |= SPI_CPHA;
1911}
1912
1913static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1914{
1915 struct acpi_spi_lookup *lookup = data;
1916 struct spi_controller *ctlr = lookup->ctlr;
1917
1918 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1919 struct acpi_resource_spi_serialbus *sb;
1920 acpi_handle parent_handle;
1921 acpi_status status;
1922
1923 sb = &ares->data.spi_serial_bus;
1924 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1925
1926 status = acpi_get_handle(NULL,
1927 sb->resource_source.string_ptr,
1928 &parent_handle);
1929
1930 if (ACPI_FAILURE(status) ||
1931 ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
1932 return -ENODEV;
1933
1934 /*
1935 * ACPI DeviceSelection numbering is handled by the
1936 * host controller driver in Windows and can vary
1937 * from driver to driver. In Linux we always expect
1938 * 0 .. max - 1 so we need to ask the driver to
1939 * translate between the two schemes.
1940 */
1941 if (ctlr->fw_translate_cs) {
1942 int cs = ctlr->fw_translate_cs(ctlr,
1943 sb->device_selection);
1944 if (cs < 0)
1945 return cs;
1946 lookup->chip_select = cs;
1947 } else {
1948 lookup->chip_select = sb->device_selection;
1949 }
1950
1951 lookup->max_speed_hz = sb->connection_speed;
1952
1953 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1954 lookup->mode |= SPI_CPHA;
1955 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1956 lookup->mode |= SPI_CPOL;
1957 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1958 lookup->mode |= SPI_CS_HIGH;
1959 }
1960 } else if (lookup->irq < 0) {
1961 struct resource r;
1962
1963 if (acpi_dev_resource_interrupt(ares, 0, &r))
1964 lookup->irq = r.start;
1965 }
1966
1967 /* Always tell the ACPI core to skip this resource */
1968 return 1;
1969}
1970
1971static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1972 struct acpi_device *adev)
1973{
1974 acpi_handle parent_handle = NULL;
1975 struct list_head resource_list;
1976 struct acpi_spi_lookup lookup = {};
1977 struct spi_device *spi;
1978 int ret;
1979
1980 if (acpi_bus_get_status(adev) || !adev->status.present ||
1981 acpi_device_enumerated(adev))
1982 return AE_OK;
1983
1984 lookup.ctlr = ctlr;
1985 lookup.irq = -1;
1986
1987 INIT_LIST_HEAD(&resource_list);
1988 ret = acpi_dev_get_resources(adev, &resource_list,
1989 acpi_spi_add_resource, &lookup);
1990 acpi_dev_free_resource_list(&resource_list);
1991
1992 if (ret < 0)
1993 /* found SPI in _CRS but it points to another controller */
1994 return AE_OK;
1995
1996 if (!lookup.max_speed_hz &&
1997 !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
1998 ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
1999 /* Apple does not use _CRS but nested devices for SPI slaves */
2000 acpi_spi_parse_apple_properties(adev, &lookup);
2001 }
2002
2003 if (!lookup.max_speed_hz)
2004 return AE_OK;
2005
2006 spi = spi_alloc_device(ctlr);
2007 if (!spi) {
2008 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2009 dev_name(&adev->dev));
2010 return AE_NO_MEMORY;
2011 }
2012
2013 ACPI_COMPANION_SET(&spi->dev, adev);
2014 spi->max_speed_hz = lookup.max_speed_hz;
2015 spi->mode = lookup.mode;
2016 spi->irq = lookup.irq;
2017 spi->bits_per_word = lookup.bits_per_word;
2018 spi->chip_select = lookup.chip_select;
2019
2020 acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2021 sizeof(spi->modalias));
2022
2023 if (spi->irq < 0)
2024 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2025
2026 acpi_device_set_enumerated(adev);
2027
2028 adev->power.flags.ignore_parent = true;
2029 if (spi_add_device(spi)) {
2030 adev->power.flags.ignore_parent = false;
2031 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2032 dev_name(&adev->dev));
2033 spi_dev_put(spi);
2034 }
2035
2036 return AE_OK;
2037}
2038
2039static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2040 void *data, void **return_value)
2041{
2042 struct spi_controller *ctlr = data;
2043 struct acpi_device *adev;
2044
2045 if (acpi_bus_get_device(handle, &adev))
2046 return AE_OK;
2047
2048 return acpi_register_spi_device(ctlr, adev);
2049}
2050
2051#define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
2052
2053static void acpi_register_spi_devices(struct spi_controller *ctlr)
2054{
2055 acpi_status status;
2056 acpi_handle handle;
2057
2058 handle = ACPI_HANDLE(ctlr->dev.parent);
2059 if (!handle)
2060 return;
2061
2062 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2063 SPI_ACPI_ENUMERATE_MAX_DEPTH,
2064 acpi_spi_add_device, NULL, ctlr, NULL);
2065 if (ACPI_FAILURE(status))
2066 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2067}
2068#else
2069static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2070#endif /* CONFIG_ACPI */
2071
2072static void spi_controller_release(struct device *dev)
2073{
2074 struct spi_controller *ctlr;
2075
2076 ctlr = container_of(dev, struct spi_controller, dev);
2077 kfree(ctlr);
2078}
2079
2080static struct class spi_master_class = {
2081 .name = "spi_master",
2082 .owner = THIS_MODULE,
2083 .dev_release = spi_controller_release,
2084 .dev_groups = spi_master_groups,
2085};
2086
2087#ifdef CONFIG_SPI_SLAVE
2088/**
2089 * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2090 * controller
2091 * @spi: device used for the current transfer
2092 */
2093int spi_slave_abort(struct spi_device *spi)
2094{
2095 struct spi_controller *ctlr = spi->controller;
2096
2097 if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2098 return ctlr->slave_abort(ctlr);
2099
2100 return -ENOTSUPP;
2101}
2102EXPORT_SYMBOL_GPL(spi_slave_abort);
2103
2104static int match_true(struct device *dev, void *data)
2105{
2106 return 1;
2107}
2108
2109static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2110 char *buf)
2111{
2112 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2113 dev);
2114 struct device *child;
2115
2116 child = device_find_child(&ctlr->dev, NULL, match_true);
2117 return sprintf(buf, "%s\n",
2118 child ? to_spi_device(child)->modalias : NULL);
2119}
2120
2121static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2122 const char *buf, size_t count)
2123{
2124 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2125 dev);
2126 struct spi_device *spi;
2127 struct device *child;
2128 char name[32];
2129 int rc;
2130
2131 rc = sscanf(buf, "%31s", name);
2132 if (rc != 1 || !name[0])
2133 return -EINVAL;
2134
2135 child = device_find_child(&ctlr->dev, NULL, match_true);
2136 if (child) {
2137 /* Remove registered slave */
2138 device_unregister(child);
2139 put_device(child);
2140 }
2141
2142 if (strcmp(name, "(null)")) {
2143 /* Register new slave */
2144 spi = spi_alloc_device(ctlr);
2145 if (!spi)
2146 return -ENOMEM;
2147
2148 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2149
2150 rc = spi_add_device(spi);
2151 if (rc) {
2152 spi_dev_put(spi);
2153 return rc;
2154 }
2155 }
2156
2157 return count;
2158}
2159
2160static DEVICE_ATTR_RW(slave);
2161
2162static struct attribute *spi_slave_attrs[] = {
2163 &dev_attr_slave.attr,
2164 NULL,
2165};
2166
2167static const struct attribute_group spi_slave_group = {
2168 .attrs = spi_slave_attrs,
2169};
2170
2171static const struct attribute_group *spi_slave_groups[] = {
2172 &spi_controller_statistics_group,
2173 &spi_slave_group,
2174 NULL,
2175};
2176
2177static struct class spi_slave_class = {
2178 .name = "spi_slave",
2179 .owner = THIS_MODULE,
2180 .dev_release = spi_controller_release,
2181 .dev_groups = spi_slave_groups,
2182};
2183#else
2184extern struct class spi_slave_class; /* dummy */
2185#endif
2186
2187/**
2188 * __spi_alloc_controller - allocate an SPI master or slave controller
2189 * @dev: the controller, possibly using the platform_bus
2190 * @size: how much zeroed driver-private data to allocate; the pointer to this
2191 * memory is in the driver_data field of the returned device, accessible
2192 * with spi_controller_get_devdata(); the memory is cacheline aligned;
2193 * drivers granting DMA access to portions of their private data need to
2194 * round up @size using ALIGN(size, dma_get_cache_alignment()).
2195 * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2196 * slave (true) controller
2197 * Context: can sleep
2198 *
2199 * This call is used only by SPI controller drivers, which are the
2200 * only ones directly touching chip registers. It's how they allocate
2201 * an spi_controller structure, prior to calling spi_register_controller().
2202 *
2203 * This must be called from context that can sleep.
2204 *
2205 * The caller is responsible for assigning the bus number and initializing the
2206 * controller's methods before calling spi_register_controller(); and (after
2207 * errors adding the device) calling spi_controller_put() to prevent a memory
2208 * leak.
2209 *
2210 * Return: the SPI controller structure on success, else NULL.
2211 */
2212struct spi_controller *__spi_alloc_controller(struct device *dev,
2213 unsigned int size, bool slave)
2214{
2215 struct spi_controller *ctlr;
2216 size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2217
2218 if (!dev)
2219 return NULL;
2220
2221 ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2222 if (!ctlr)
2223 return NULL;
2224
2225 device_initialize(&ctlr->dev);
2226 ctlr->bus_num = -1;
2227 ctlr->num_chipselect = 1;
2228 ctlr->slave = slave;
2229 if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2230 ctlr->dev.class = &spi_slave_class;
2231 else
2232 ctlr->dev.class = &spi_master_class;
2233 ctlr->dev.parent = dev;
2234 pm_suspend_ignore_children(&ctlr->dev, true);
2235 spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2236
2237 return ctlr;
2238}
2239EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2240
2241#ifdef CONFIG_OF
2242static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2243{
2244 int nb, i, *cs;
2245 struct device_node *np = ctlr->dev.of_node;
2246
2247 if (!np)
2248 return 0;
2249
2250 nb = of_gpio_named_count(np, "cs-gpios");
2251 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2252
2253 /* Return error only for an incorrectly formed cs-gpios property */
2254 if (nb == 0 || nb == -ENOENT)
2255 return 0;
2256 else if (nb < 0)
2257 return nb;
2258
2259 cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2260 GFP_KERNEL);
2261 ctlr->cs_gpios = cs;
2262
2263 if (!ctlr->cs_gpios)
2264 return -ENOMEM;
2265
2266 for (i = 0; i < ctlr->num_chipselect; i++)
2267 cs[i] = -ENOENT;
2268
2269 for (i = 0; i < nb; i++)
2270 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2271
2272 return 0;
2273}
2274#else
2275static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2276{
2277 return 0;
2278}
2279#endif
2280
2281/**
2282 * spi_get_gpio_descs() - grab chip select GPIOs for the master
2283 * @ctlr: The SPI master to grab GPIO descriptors for
2284 */
2285static int spi_get_gpio_descs(struct spi_controller *ctlr)
2286{
2287 int nb, i;
2288 struct gpio_desc **cs;
2289 struct device *dev = &ctlr->dev;
2290
2291 nb = gpiod_count(dev, "cs");
2292 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2293
2294 /* No GPIOs at all is fine, else return the error */
2295 if (nb == 0 || nb == -ENOENT)
2296 return 0;
2297 else if (nb < 0)
2298 return nb;
2299
2300 cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2301 GFP_KERNEL);
2302 if (!cs)
2303 return -ENOMEM;
2304 ctlr->cs_gpiods = cs;
2305
2306 for (i = 0; i < nb; i++) {
2307 /*
2308 * Most chipselects are active low, the inverted
2309 * semantics are handled by special quirks in gpiolib,
2310 * so initializing them GPIOD_OUT_LOW here means
2311 * "unasserted", in most cases this will drive the physical
2312 * line high.
2313 */
2314 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2315 GPIOD_OUT_LOW);
2316 if (IS_ERR(cs[i]))
2317 return PTR_ERR(cs[i]);
2318
2319 if (cs[i]) {
2320 /*
2321 * If we find a CS GPIO, name it after the device and
2322 * chip select line.
2323 */
2324 char *gpioname;
2325
2326 gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2327 dev_name(dev), i);
2328 if (!gpioname)
2329 return -ENOMEM;
2330 gpiod_set_consumer_name(cs[i], gpioname);
2331 }
2332 }
2333
2334 return 0;
2335}
2336
2337static int spi_controller_check_ops(struct spi_controller *ctlr)
2338{
2339 /*
2340 * The controller may implement only the high-level SPI-memory like
2341 * operations if it does not support regular SPI transfers, and this is
2342 * valid use case.
2343 * If ->mem_ops is NULL, we request that at least one of the
2344 * ->transfer_xxx() method be implemented.
2345 */
2346 if (ctlr->mem_ops) {
2347 if (!ctlr->mem_ops->exec_op)
2348 return -EINVAL;
2349 } else if (!ctlr->transfer && !ctlr->transfer_one &&
2350 !ctlr->transfer_one_message) {
2351 return -EINVAL;
2352 }
2353
2354 return 0;
2355}
2356
2357/**
2358 * spi_register_controller - register SPI master or slave controller
2359 * @ctlr: initialized master, originally from spi_alloc_master() or
2360 * spi_alloc_slave()
2361 * Context: can sleep
2362 *
2363 * SPI controllers connect to their drivers using some non-SPI bus,
2364 * such as the platform bus. The final stage of probe() in that code
2365 * includes calling spi_register_controller() to hook up to this SPI bus glue.
2366 *
2367 * SPI controllers use board specific (often SOC specific) bus numbers,
2368 * and board-specific addressing for SPI devices combines those numbers
2369 * with chip select numbers. Since SPI does not directly support dynamic
2370 * device identification, boards need configuration tables telling which
2371 * chip is at which address.
2372 *
2373 * This must be called from context that can sleep. It returns zero on
2374 * success, else a negative error code (dropping the controller's refcount).
2375 * After a successful return, the caller is responsible for calling
2376 * spi_unregister_controller().
2377 *
2378 * Return: zero on success, else a negative error code.
2379 */
2380int spi_register_controller(struct spi_controller *ctlr)
2381{
2382 struct device *dev = ctlr->dev.parent;
2383 struct boardinfo *bi;
2384 int status;
2385 int id, first_dynamic;
2386
2387 if (!dev)
2388 return -ENODEV;
2389
2390 /*
2391 * Make sure all necessary hooks are implemented before registering
2392 * the SPI controller.
2393 */
2394 status = spi_controller_check_ops(ctlr);
2395 if (status)
2396 return status;
2397
2398 if (ctlr->bus_num >= 0) {
2399 /* devices with a fixed bus num must check-in with the num */
2400 mutex_lock(&board_lock);
2401 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2402 ctlr->bus_num + 1, GFP_KERNEL);
2403 mutex_unlock(&board_lock);
2404 if (WARN(id < 0, "couldn't get idr"))
2405 return id == -ENOSPC ? -EBUSY : id;
2406 ctlr->bus_num = id;
2407 } else if (ctlr->dev.of_node) {
2408 /* allocate dynamic bus number using Linux idr */
2409 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2410 if (id >= 0) {
2411 ctlr->bus_num = id;
2412 mutex_lock(&board_lock);
2413 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2414 ctlr->bus_num + 1, GFP_KERNEL);
2415 mutex_unlock(&board_lock);
2416 if (WARN(id < 0, "couldn't get idr"))
2417 return id == -ENOSPC ? -EBUSY : id;
2418 }
2419 }
2420 if (ctlr->bus_num < 0) {
2421 first_dynamic = of_alias_get_highest_id("spi");
2422 if (first_dynamic < 0)
2423 first_dynamic = 0;
2424 else
2425 first_dynamic++;
2426
2427 mutex_lock(&board_lock);
2428 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2429 0, GFP_KERNEL);
2430 mutex_unlock(&board_lock);
2431 if (WARN(id < 0, "couldn't get idr"))
2432 return id;
2433 ctlr->bus_num = id;
2434 }
2435 INIT_LIST_HEAD(&ctlr->queue);
2436 spin_lock_init(&ctlr->queue_lock);
2437 spin_lock_init(&ctlr->bus_lock_spinlock);
2438 mutex_init(&ctlr->bus_lock_mutex);
2439 mutex_init(&ctlr->io_mutex);
2440 ctlr->bus_lock_flag = 0;
2441 init_completion(&ctlr->xfer_completion);
2442 if (!ctlr->max_dma_len)
2443 ctlr->max_dma_len = INT_MAX;
2444
2445 /* register the device, then userspace will see it.
2446 * registration fails if the bus ID is in use.
2447 */
2448 dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2449
2450 if (!spi_controller_is_slave(ctlr)) {
2451 if (ctlr->use_gpio_descriptors) {
2452 status = spi_get_gpio_descs(ctlr);
2453 if (status)
2454 return status;
2455 /*
2456 * A controller using GPIO descriptors always
2457 * supports SPI_CS_HIGH if need be.
2458 */
2459 ctlr->mode_bits |= SPI_CS_HIGH;
2460 } else {
2461 /* Legacy code path for GPIOs from DT */
2462 status = of_spi_get_gpio_numbers(ctlr);
2463 if (status)
2464 return status;
2465 }
2466 }
2467
2468 /*
2469 * Even if it's just one always-selected device, there must
2470 * be at least one chipselect.
2471 */
2472 if (!ctlr->num_chipselect)
2473 return -EINVAL;
2474
2475 status = device_add(&ctlr->dev);
2476 if (status < 0) {
2477 /* free bus id */
2478 mutex_lock(&board_lock);
2479 idr_remove(&spi_master_idr, ctlr->bus_num);
2480 mutex_unlock(&board_lock);
2481 goto done;
2482 }
2483 dev_dbg(dev, "registered %s %s\n",
2484 spi_controller_is_slave(ctlr) ? "slave" : "master",
2485 dev_name(&ctlr->dev));
2486
2487 /*
2488 * If we're using a queued driver, start the queue. Note that we don't
2489 * need the queueing logic if the driver is only supporting high-level
2490 * memory operations.
2491 */
2492 if (ctlr->transfer) {
2493 dev_info(dev, "controller is unqueued, this is deprecated\n");
2494 } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2495 status = spi_controller_initialize_queue(ctlr);
2496 if (status) {
2497 device_del(&ctlr->dev);
2498 /* free bus id */
2499 mutex_lock(&board_lock);
2500 idr_remove(&spi_master_idr, ctlr->bus_num);
2501 mutex_unlock(&board_lock);
2502 goto done;
2503 }
2504 }
2505 /* add statistics */
2506 spin_lock_init(&ctlr->statistics.lock);
2507
2508 mutex_lock(&board_lock);
2509 list_add_tail(&ctlr->list, &spi_controller_list);
2510 list_for_each_entry(bi, &board_list, list)
2511 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2512 mutex_unlock(&board_lock);
2513
2514 /* Register devices from the device tree and ACPI */
2515 of_register_spi_devices(ctlr);
2516 acpi_register_spi_devices(ctlr);
2517done:
2518 return status;
2519}
2520EXPORT_SYMBOL_GPL(spi_register_controller);
2521
2522static void devm_spi_unregister(struct device *dev, void *res)
2523{
2524 spi_unregister_controller(*(struct spi_controller **)res);
2525}
2526
2527/**
2528 * devm_spi_register_controller - register managed SPI master or slave
2529 * controller
2530 * @dev: device managing SPI controller
2531 * @ctlr: initialized controller, originally from spi_alloc_master() or
2532 * spi_alloc_slave()
2533 * Context: can sleep
2534 *
2535 * Register a SPI device as with spi_register_controller() which will
2536 * automatically be unregistered and freed.
2537 *
2538 * Return: zero on success, else a negative error code.
2539 */
2540int devm_spi_register_controller(struct device *dev,
2541 struct spi_controller *ctlr)
2542{
2543 struct spi_controller **ptr;
2544 int ret;
2545
2546 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2547 if (!ptr)
2548 return -ENOMEM;
2549
2550 ret = spi_register_controller(ctlr);
2551 if (!ret) {
2552 *ptr = ctlr;
2553 devres_add(dev, ptr);
2554 } else {
2555 devres_free(ptr);
2556 }
2557
2558 return ret;
2559}
2560EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2561
2562static int __unregister(struct device *dev, void *null)
2563{
2564 spi_unregister_device(to_spi_device(dev));
2565 return 0;
2566}
2567
2568/**
2569 * spi_unregister_controller - unregister SPI master or slave controller
2570 * @ctlr: the controller being unregistered
2571 * Context: can sleep
2572 *
2573 * This call is used only by SPI controller drivers, which are the
2574 * only ones directly touching chip registers.
2575 *
2576 * This must be called from context that can sleep.
2577 *
2578 * Note that this function also drops a reference to the controller.
2579 */
2580void spi_unregister_controller(struct spi_controller *ctlr)
2581{
2582 struct spi_controller *found;
2583 int id = ctlr->bus_num;
2584
2585 /* First make sure that this controller was ever added */
2586 mutex_lock(&board_lock);
2587 found = idr_find(&spi_master_idr, id);
2588 mutex_unlock(&board_lock);
2589 if (ctlr->queued) {
2590 if (spi_destroy_queue(ctlr))
2591 dev_err(&ctlr->dev, "queue remove failed\n");
2592 }
2593 mutex_lock(&board_lock);
2594 list_del(&ctlr->list);
2595 mutex_unlock(&board_lock);
2596
2597 device_for_each_child(&ctlr->dev, NULL, __unregister);
2598 device_unregister(&ctlr->dev);
2599 /* free bus id */
2600 mutex_lock(&board_lock);
2601 if (found == ctlr)
2602 idr_remove(&spi_master_idr, id);
2603 mutex_unlock(&board_lock);
2604}
2605EXPORT_SYMBOL_GPL(spi_unregister_controller);
2606
2607int spi_controller_suspend(struct spi_controller *ctlr)
2608{
2609 int ret;
2610
2611 /* Basically no-ops for non-queued controllers */
2612 if (!ctlr->queued)
2613 return 0;
2614
2615 ret = spi_stop_queue(ctlr);
2616 if (ret)
2617 dev_err(&ctlr->dev, "queue stop failed\n");
2618
2619 return ret;
2620}
2621EXPORT_SYMBOL_GPL(spi_controller_suspend);
2622
2623int spi_controller_resume(struct spi_controller *ctlr)
2624{
2625 int ret;
2626
2627 if (!ctlr->queued)
2628 return 0;
2629
2630 ret = spi_start_queue(ctlr);
2631 if (ret)
2632 dev_err(&ctlr->dev, "queue restart failed\n");
2633
2634 return ret;
2635}
2636EXPORT_SYMBOL_GPL(spi_controller_resume);
2637
2638static int __spi_controller_match(struct device *dev, const void *data)
2639{
2640 struct spi_controller *ctlr;
2641 const u16 *bus_num = data;
2642
2643 ctlr = container_of(dev, struct spi_controller, dev);
2644 return ctlr->bus_num == *bus_num;
2645}
2646
2647/**
2648 * spi_busnum_to_master - look up master associated with bus_num
2649 * @bus_num: the master's bus number
2650 * Context: can sleep
2651 *
2652 * This call may be used with devices that are registered after
2653 * arch init time. It returns a refcounted pointer to the relevant
2654 * spi_controller (which the caller must release), or NULL if there is
2655 * no such master registered.
2656 *
2657 * Return: the SPI master structure on success, else NULL.
2658 */
2659struct spi_controller *spi_busnum_to_master(u16 bus_num)
2660{
2661 struct device *dev;
2662 struct spi_controller *ctlr = NULL;
2663
2664 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2665 __spi_controller_match);
2666 if (dev)
2667 ctlr = container_of(dev, struct spi_controller, dev);
2668 /* reference got in class_find_device */
2669 return ctlr;
2670}
2671EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2672
2673/*-------------------------------------------------------------------------*/
2674
2675/* Core methods for SPI resource management */
2676
2677/**
2678 * spi_res_alloc - allocate a spi resource that is life-cycle managed
2679 * during the processing of a spi_message while using
2680 * spi_transfer_one
2681 * @spi: the spi device for which we allocate memory
2682 * @release: the release code to execute for this resource
2683 * @size: size to alloc and return
2684 * @gfp: GFP allocation flags
2685 *
2686 * Return: the pointer to the allocated data
2687 *
2688 * This may get enhanced in the future to allocate from a memory pool
2689 * of the @spi_device or @spi_controller to avoid repeated allocations.
2690 */
2691void *spi_res_alloc(struct spi_device *spi,
2692 spi_res_release_t release,
2693 size_t size, gfp_t gfp)
2694{
2695 struct spi_res *sres;
2696
2697 sres = kzalloc(sizeof(*sres) + size, gfp);
2698 if (!sres)
2699 return NULL;
2700
2701 INIT_LIST_HEAD(&sres->entry);
2702 sres->release = release;
2703
2704 return sres->data;
2705}
2706EXPORT_SYMBOL_GPL(spi_res_alloc);
2707
2708/**
2709 * spi_res_free - free an spi resource
2710 * @res: pointer to the custom data of a resource
2711 *
2712 */
2713void spi_res_free(void *res)
2714{
2715 struct spi_res *sres = container_of(res, struct spi_res, data);
2716
2717 if (!res)
2718 return;
2719
2720 WARN_ON(!list_empty(&sres->entry));
2721 kfree(sres);
2722}
2723EXPORT_SYMBOL_GPL(spi_res_free);
2724
2725/**
2726 * spi_res_add - add a spi_res to the spi_message
2727 * @message: the spi message
2728 * @res: the spi_resource
2729 */
2730void spi_res_add(struct spi_message *message, void *res)
2731{
2732 struct spi_res *sres = container_of(res, struct spi_res, data);
2733
2734 WARN_ON(!list_empty(&sres->entry));
2735 list_add_tail(&sres->entry, &message->resources);
2736}
2737EXPORT_SYMBOL_GPL(spi_res_add);
2738
2739/**
2740 * spi_res_release - release all spi resources for this message
2741 * @ctlr: the @spi_controller
2742 * @message: the @spi_message
2743 */
2744void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2745{
2746 struct spi_res *res, *tmp;
2747
2748 list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
2749 if (res->release)
2750 res->release(ctlr, message, res->data);
2751
2752 list_del(&res->entry);
2753
2754 kfree(res);
2755 }
2756}
2757EXPORT_SYMBOL_GPL(spi_res_release);
2758
2759/*-------------------------------------------------------------------------*/
2760
2761/* Core methods for spi_message alterations */
2762
2763static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2764 struct spi_message *msg,
2765 void *res)
2766{
2767 struct spi_replaced_transfers *rxfer = res;
2768 size_t i;
2769
2770 /* call extra callback if requested */
2771 if (rxfer->release)
2772 rxfer->release(ctlr, msg, res);
2773
2774 /* insert replaced transfers back into the message */
2775 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2776
2777 /* remove the formerly inserted entries */
2778 for (i = 0; i < rxfer->inserted; i++)
2779 list_del(&rxfer->inserted_transfers[i].transfer_list);
2780}
2781
2782/**
2783 * spi_replace_transfers - replace transfers with several transfers
2784 * and register change with spi_message.resources
2785 * @msg: the spi_message we work upon
2786 * @xfer_first: the first spi_transfer we want to replace
2787 * @remove: number of transfers to remove
2788 * @insert: the number of transfers we want to insert instead
2789 * @release: extra release code necessary in some circumstances
2790 * @extradatasize: extra data to allocate (with alignment guarantees
2791 * of struct @spi_transfer)
2792 * @gfp: gfp flags
2793 *
2794 * Returns: pointer to @spi_replaced_transfers,
2795 * PTR_ERR(...) in case of errors.
2796 */
2797struct spi_replaced_transfers *spi_replace_transfers(
2798 struct spi_message *msg,
2799 struct spi_transfer *xfer_first,
2800 size_t remove,
2801 size_t insert,
2802 spi_replaced_release_t release,
2803 size_t extradatasize,
2804 gfp_t gfp)
2805{
2806 struct spi_replaced_transfers *rxfer;
2807 struct spi_transfer *xfer;
2808 size_t i;
2809
2810 /* allocate the structure using spi_res */
2811 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2812 struct_size(rxfer, inserted_transfers, insert)
2813 + extradatasize,
2814 gfp);
2815 if (!rxfer)
2816 return ERR_PTR(-ENOMEM);
2817
2818 /* the release code to invoke before running the generic release */
2819 rxfer->release = release;
2820
2821 /* assign extradata */
2822 if (extradatasize)
2823 rxfer->extradata =
2824 &rxfer->inserted_transfers[insert];
2825
2826 /* init the replaced_transfers list */
2827 INIT_LIST_HEAD(&rxfer->replaced_transfers);
2828
2829 /* assign the list_entry after which we should reinsert
2830 * the @replaced_transfers - it may be spi_message.messages!
2831 */
2832 rxfer->replaced_after = xfer_first->transfer_list.prev;
2833
2834 /* remove the requested number of transfers */
2835 for (i = 0; i < remove; i++) {
2836 /* if the entry after replaced_after it is msg->transfers
2837 * then we have been requested to remove more transfers
2838 * than are in the list
2839 */
2840 if (rxfer->replaced_after->next == &msg->transfers) {
2841 dev_err(&msg->spi->dev,
2842 "requested to remove more spi_transfers than are available\n");
2843 /* insert replaced transfers back into the message */
2844 list_splice(&rxfer->replaced_transfers,
2845 rxfer->replaced_after);
2846
2847 /* free the spi_replace_transfer structure */
2848 spi_res_free(rxfer);
2849
2850 /* and return with an error */
2851 return ERR_PTR(-EINVAL);
2852 }
2853
2854 /* remove the entry after replaced_after from list of
2855 * transfers and add it to list of replaced_transfers
2856 */
2857 list_move_tail(rxfer->replaced_after->next,
2858 &rxfer->replaced_transfers);
2859 }
2860
2861 /* create copy of the given xfer with identical settings
2862 * based on the first transfer to get removed
2863 */
2864 for (i = 0; i < insert; i++) {
2865 /* we need to run in reverse order */
2866 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2867
2868 /* copy all spi_transfer data */
2869 memcpy(xfer, xfer_first, sizeof(*xfer));
2870
2871 /* add to list */
2872 list_add(&xfer->transfer_list, rxfer->replaced_after);
2873
2874 /* clear cs_change and delay_usecs for all but the last */
2875 if (i) {
2876 xfer->cs_change = false;
2877 xfer->delay_usecs = 0;
2878 }
2879 }
2880
2881 /* set up inserted */
2882 rxfer->inserted = insert;
2883
2884 /* and register it with spi_res/spi_message */
2885 spi_res_add(msg, rxfer);
2886
2887 return rxfer;
2888}
2889EXPORT_SYMBOL_GPL(spi_replace_transfers);
2890
2891static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2892 struct spi_message *msg,
2893 struct spi_transfer **xferp,
2894 size_t maxsize,
2895 gfp_t gfp)
2896{
2897 struct spi_transfer *xfer = *xferp, *xfers;
2898 struct spi_replaced_transfers *srt;
2899 size_t offset;
2900 size_t count, i;
2901
2902 /* calculate how many we have to replace */
2903 count = DIV_ROUND_UP(xfer->len, maxsize);
2904
2905 /* create replacement */
2906 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2907 if (IS_ERR(srt))
2908 return PTR_ERR(srt);
2909 xfers = srt->inserted_transfers;
2910
2911 /* now handle each of those newly inserted spi_transfers
2912 * note that the replacements spi_transfers all are preset
2913 * to the same values as *xferp, so tx_buf, rx_buf and len
2914 * are all identical (as well as most others)
2915 * so we just have to fix up len and the pointers.
2916 *
2917 * this also includes support for the depreciated
2918 * spi_message.is_dma_mapped interface
2919 */
2920
2921 /* the first transfer just needs the length modified, so we
2922 * run it outside the loop
2923 */
2924 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2925
2926 /* all the others need rx_buf/tx_buf also set */
2927 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2928 /* update rx_buf, tx_buf and dma */
2929 if (xfers[i].rx_buf)
2930 xfers[i].rx_buf += offset;
2931 if (xfers[i].rx_dma)
2932 xfers[i].rx_dma += offset;
2933 if (xfers[i].tx_buf)
2934 xfers[i].tx_buf += offset;
2935 if (xfers[i].tx_dma)
2936 xfers[i].tx_dma += offset;
2937
2938 /* update length */
2939 xfers[i].len = min(maxsize, xfers[i].len - offset);
2940 }
2941
2942 /* we set up xferp to the last entry we have inserted,
2943 * so that we skip those already split transfers
2944 */
2945 *xferp = &xfers[count - 1];
2946
2947 /* increment statistics counters */
2948 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2949 transfers_split_maxsize);
2950 SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2951 transfers_split_maxsize);
2952
2953 return 0;
2954}
2955
2956/**
2957 * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2958 * when an individual transfer exceeds a
2959 * certain size
2960 * @ctlr: the @spi_controller for this transfer
2961 * @msg: the @spi_message to transform
2962 * @maxsize: the maximum when to apply this
2963 * @gfp: GFP allocation flags
2964 *
2965 * Return: status of transformation
2966 */
2967int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2968 struct spi_message *msg,
2969 size_t maxsize,
2970 gfp_t gfp)
2971{
2972 struct spi_transfer *xfer;
2973 int ret;
2974
2975 /* iterate over the transfer_list,
2976 * but note that xfer is advanced to the last transfer inserted
2977 * to avoid checking sizes again unnecessarily (also xfer does
2978 * potentiall belong to a different list by the time the
2979 * replacement has happened
2980 */
2981 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2982 if (xfer->len > maxsize) {
2983 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2984 maxsize, gfp);
2985 if (ret)
2986 return ret;
2987 }
2988 }
2989
2990 return 0;
2991}
2992EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2993
2994/*-------------------------------------------------------------------------*/
2995
2996/* Core methods for SPI controller protocol drivers. Some of the
2997 * other core methods are currently defined as inline functions.
2998 */
2999
3000static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3001 u8 bits_per_word)
3002{
3003 if (ctlr->bits_per_word_mask) {
3004 /* Only 32 bits fit in the mask */
3005 if (bits_per_word > 32)
3006 return -EINVAL;
3007 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3008 return -EINVAL;
3009 }
3010
3011 return 0;
3012}
3013
3014/**
3015 * spi_setup - setup SPI mode and clock rate
3016 * @spi: the device whose settings are being modified
3017 * Context: can sleep, and no requests are queued to the device
3018 *
3019 * SPI protocol drivers may need to update the transfer mode if the
3020 * device doesn't work with its default. They may likewise need
3021 * to update clock rates or word sizes from initial values. This function
3022 * changes those settings, and must be called from a context that can sleep.
3023 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3024 * effect the next time the device is selected and data is transferred to
3025 * or from it. When this function returns, the spi device is deselected.
3026 *
3027 * Note that this call will fail if the protocol driver specifies an option
3028 * that the underlying controller or its driver does not support. For
3029 * example, not all hardware supports wire transfers using nine bit words,
3030 * LSB-first wire encoding, or active-high chipselects.
3031 *
3032 * Return: zero on success, else a negative error code.
3033 */
3034int spi_setup(struct spi_device *spi)
3035{
3036 unsigned bad_bits, ugly_bits;
3037 int status;
3038
3039 /* check mode to prevent that DUAL and QUAD set at the same time
3040 */
3041 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3042 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3043 dev_err(&spi->dev,
3044 "setup: can not select dual and quad at the same time\n");
3045 return -EINVAL;
3046 }
3047 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3048 */
3049 if ((spi->mode & SPI_3WIRE) && (spi->mode &
3050 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3051 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3052 return -EINVAL;
3053 /* help drivers fail *cleanly* when they need options
3054 * that aren't supported with their current controller
3055 * SPI_CS_WORD has a fallback software implementation,
3056 * so it is ignored here.
3057 */
3058 bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3059 /* nothing prevents from working with active-high CS in case if it
3060 * is driven by GPIO.
3061 */
3062 if (gpio_is_valid(spi->cs_gpio))
3063 bad_bits &= ~SPI_CS_HIGH;
3064 ugly_bits = bad_bits &
3065 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3066 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3067 if (ugly_bits) {
3068 dev_warn(&spi->dev,
3069 "setup: ignoring unsupported mode bits %x\n",
3070 ugly_bits);
3071 spi->mode &= ~ugly_bits;
3072 bad_bits &= ~ugly_bits;
3073 }
3074 if (bad_bits) {
3075 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3076 bad_bits);
3077 return -EINVAL;
3078 }
3079
3080 if (!spi->bits_per_word)
3081 spi->bits_per_word = 8;
3082
3083 status = __spi_validate_bits_per_word(spi->controller,
3084 spi->bits_per_word);
3085 if (status)
3086 return status;
3087
3088 if (!spi->max_speed_hz)
3089 spi->max_speed_hz = spi->controller->max_speed_hz;
3090
3091 if (spi->controller->setup)
3092 status = spi->controller->setup(spi);
3093
3094 spi_set_cs(spi, false);
3095
3096 if (spi->rt && !spi->controller->rt) {
3097 spi->controller->rt = true;
3098 spi_set_thread_rt(spi->controller);
3099 }
3100
3101 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3102 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3103 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3104 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3105 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3106 (spi->mode & SPI_LOOP) ? "loopback, " : "",
3107 spi->bits_per_word, spi->max_speed_hz,
3108 status);
3109
3110 return status;
3111}
3112EXPORT_SYMBOL_GPL(spi_setup);
3113
3114/**
3115 * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3116 * @spi: the device that requires specific CS timing configuration
3117 * @setup: CS setup time in terms of clock count
3118 * @hold: CS hold time in terms of clock count
3119 * @inactive_dly: CS inactive delay between transfers in terms of clock count
3120 */
3121void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
3122 u8 inactive_dly)
3123{
3124 if (spi->controller->set_cs_timing)
3125 spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
3126}
3127EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3128
3129static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3130{
3131 struct spi_controller *ctlr = spi->controller;
3132 struct spi_transfer *xfer;
3133 int w_size;
3134
3135 if (list_empty(&message->transfers))
3136 return -EINVAL;
3137
3138 /* If an SPI controller does not support toggling the CS line on each
3139 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3140 * for the CS line, we can emulate the CS-per-word hardware function by
3141 * splitting transfers into one-word transfers and ensuring that
3142 * cs_change is set for each transfer.
3143 */
3144 if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3145 spi->cs_gpiod ||
3146 gpio_is_valid(spi->cs_gpio))) {
3147 size_t maxsize;
3148 int ret;
3149
3150 maxsize = (spi->bits_per_word + 7) / 8;
3151
3152 /* spi_split_transfers_maxsize() requires message->spi */
3153 message->spi = spi;
3154
3155 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3156 GFP_KERNEL);
3157 if (ret)
3158 return ret;
3159
3160 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3161 /* don't change cs_change on the last entry in the list */
3162 if (list_is_last(&xfer->transfer_list, &message->transfers))
3163 break;
3164 xfer->cs_change = 1;
3165 }
3166 }
3167
3168 /* Half-duplex links include original MicroWire, and ones with
3169 * only one data pin like SPI_3WIRE (switches direction) or where
3170 * either MOSI or MISO is missing. They can also be caused by
3171 * software limitations.
3172 */
3173 if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3174 (spi->mode & SPI_3WIRE)) {
3175 unsigned flags = ctlr->flags;
3176
3177 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3178 if (xfer->rx_buf && xfer->tx_buf)
3179 return -EINVAL;
3180 if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3181 return -EINVAL;
3182 if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3183 return -EINVAL;
3184 }
3185 }
3186
3187 /**
3188 * Set transfer bits_per_word and max speed as spi device default if
3189 * it is not set for this transfer.
3190 * Set transfer tx_nbits and rx_nbits as single transfer default
3191 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3192 * Ensure transfer word_delay is at least as long as that required by
3193 * device itself.
3194 */
3195 message->frame_length = 0;
3196 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3197 xfer->effective_speed_hz = 0;
3198 message->frame_length += xfer->len;
3199 if (!xfer->bits_per_word)
3200 xfer->bits_per_word = spi->bits_per_word;
3201
3202 if (!xfer->speed_hz)
3203 xfer->speed_hz = spi->max_speed_hz;
3204
3205 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3206 xfer->speed_hz = ctlr->max_speed_hz;
3207
3208 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3209 return -EINVAL;
3210
3211 /*
3212 * SPI transfer length should be multiple of SPI word size
3213 * where SPI word size should be power-of-two multiple
3214 */
3215 if (xfer->bits_per_word <= 8)
3216 w_size = 1;
3217 else if (xfer->bits_per_word <= 16)
3218 w_size = 2;
3219 else
3220 w_size = 4;
3221
3222 /* No partial transfers accepted */
3223 if (xfer->len % w_size)
3224 return -EINVAL;
3225
3226 if (xfer->speed_hz && ctlr->min_speed_hz &&
3227 xfer->speed_hz < ctlr->min_speed_hz)
3228 return -EINVAL;
3229
3230 if (xfer->tx_buf && !xfer->tx_nbits)
3231 xfer->tx_nbits = SPI_NBITS_SINGLE;
3232 if (xfer->rx_buf && !xfer->rx_nbits)
3233 xfer->rx_nbits = SPI_NBITS_SINGLE;
3234 /* check transfer tx/rx_nbits:
3235 * 1. check the value matches one of single, dual and quad
3236 * 2. check tx/rx_nbits match the mode in spi_device
3237 */
3238 if (xfer->tx_buf) {
3239 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3240 xfer->tx_nbits != SPI_NBITS_DUAL &&
3241 xfer->tx_nbits != SPI_NBITS_QUAD)
3242 return -EINVAL;
3243 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3244 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3245 return -EINVAL;
3246 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3247 !(spi->mode & SPI_TX_QUAD))
3248 return -EINVAL;
3249 }
3250 /* check transfer rx_nbits */
3251 if (xfer->rx_buf) {
3252 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3253 xfer->rx_nbits != SPI_NBITS_DUAL &&
3254 xfer->rx_nbits != SPI_NBITS_QUAD)
3255 return -EINVAL;
3256 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3257 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3258 return -EINVAL;
3259 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3260 !(spi->mode & SPI_RX_QUAD))
3261 return -EINVAL;
3262 }
3263
3264 if (xfer->word_delay_usecs < spi->word_delay_usecs)
3265 xfer->word_delay_usecs = spi->word_delay_usecs;
3266 }
3267
3268 message->status = -EINPROGRESS;
3269
3270 return 0;
3271}
3272
3273static int __spi_async(struct spi_device *spi, struct spi_message *message)
3274{
3275 struct spi_controller *ctlr = spi->controller;
3276
3277 /*
3278 * Some controllers do not support doing regular SPI transfers. Return
3279 * ENOTSUPP when this is the case.
3280 */
3281 if (!ctlr->transfer)
3282 return -ENOTSUPP;
3283
3284 message->spi = spi;
3285
3286 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3287 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3288
3289 trace_spi_message_submit(message);
3290
3291 return ctlr->transfer(spi, message);
3292}
3293
3294/**
3295 * spi_async - asynchronous SPI transfer
3296 * @spi: device with which data will be exchanged
3297 * @message: describes the data transfers, including completion callback
3298 * Context: any (irqs may be blocked, etc)
3299 *
3300 * This call may be used in_irq and other contexts which can't sleep,
3301 * as well as from task contexts which can sleep.
3302 *
3303 * The completion callback is invoked in a context which can't sleep.
3304 * Before that invocation, the value of message->status is undefined.
3305 * When the callback is issued, message->status holds either zero (to
3306 * indicate complete success) or a negative error code. After that
3307 * callback returns, the driver which issued the transfer request may
3308 * deallocate the associated memory; it's no longer in use by any SPI
3309 * core or controller driver code.
3310 *
3311 * Note that although all messages to a spi_device are handled in
3312 * FIFO order, messages may go to different devices in other orders.
3313 * Some device might be higher priority, or have various "hard" access
3314 * time requirements, for example.
3315 *
3316 * On detection of any fault during the transfer, processing of
3317 * the entire message is aborted, and the device is deselected.
3318 * Until returning from the associated message completion callback,
3319 * no other spi_message queued to that device will be processed.
3320 * (This rule applies equally to all the synchronous transfer calls,
3321 * which are wrappers around this core asynchronous primitive.)
3322 *
3323 * Return: zero on success, else a negative error code.
3324 */
3325int spi_async(struct spi_device *spi, struct spi_message *message)
3326{
3327 struct spi_controller *ctlr = spi->controller;
3328 int ret;
3329 unsigned long flags;
3330
3331 ret = __spi_validate(spi, message);
3332 if (ret != 0)
3333 return ret;
3334
3335 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3336
3337 if (ctlr->bus_lock_flag)
3338 ret = -EBUSY;
3339 else
3340 ret = __spi_async(spi, message);
3341
3342 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3343
3344 return ret;
3345}
3346EXPORT_SYMBOL_GPL(spi_async);
3347
3348/**
3349 * spi_async_locked - version of spi_async with exclusive bus usage
3350 * @spi: device with which data will be exchanged
3351 * @message: describes the data transfers, including completion callback
3352 * Context: any (irqs may be blocked, etc)
3353 *
3354 * This call may be used in_irq and other contexts which can't sleep,
3355 * as well as from task contexts which can sleep.
3356 *
3357 * The completion callback is invoked in a context which can't sleep.
3358 * Before that invocation, the value of message->status is undefined.
3359 * When the callback is issued, message->status holds either zero (to
3360 * indicate complete success) or a negative error code. After that
3361 * callback returns, the driver which issued the transfer request may
3362 * deallocate the associated memory; it's no longer in use by any SPI
3363 * core or controller driver code.
3364 *
3365 * Note that although all messages to a spi_device are handled in
3366 * FIFO order, messages may go to different devices in other orders.
3367 * Some device might be higher priority, or have various "hard" access
3368 * time requirements, for example.
3369 *
3370 * On detection of any fault during the transfer, processing of
3371 * the entire message is aborted, and the device is deselected.
3372 * Until returning from the associated message completion callback,
3373 * no other spi_message queued to that device will be processed.
3374 * (This rule applies equally to all the synchronous transfer calls,
3375 * which are wrappers around this core asynchronous primitive.)
3376 *
3377 * Return: zero on success, else a negative error code.
3378 */
3379int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3380{
3381 struct spi_controller *ctlr = spi->controller;
3382 int ret;
3383 unsigned long flags;
3384
3385 ret = __spi_validate(spi, message);
3386 if (ret != 0)
3387 return ret;
3388
3389 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3390
3391 ret = __spi_async(spi, message);
3392
3393 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3394
3395 return ret;
3396
3397}
3398EXPORT_SYMBOL_GPL(spi_async_locked);
3399
3400/*-------------------------------------------------------------------------*/
3401
3402/* Utility methods for SPI protocol drivers, layered on
3403 * top of the core. Some other utility methods are defined as
3404 * inline functions.
3405 */
3406
3407static void spi_complete(void *arg)
3408{
3409 complete(arg);
3410}
3411
3412static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3413{
3414 DECLARE_COMPLETION_ONSTACK(done);
3415 int status;
3416 struct spi_controller *ctlr = spi->controller;
3417 unsigned long flags;
3418
3419 status = __spi_validate(spi, message);
3420 if (status != 0)
3421 return status;
3422
3423 message->complete = spi_complete;
3424 message->context = &done;
3425 message->spi = spi;
3426
3427 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3428 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3429
3430 /* If we're not using the legacy transfer method then we will
3431 * try to transfer in the calling context so special case.
3432 * This code would be less tricky if we could remove the
3433 * support for driver implemented message queues.
3434 */
3435 if (ctlr->transfer == spi_queued_transfer) {
3436 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3437
3438 trace_spi_message_submit(message);
3439
3440 status = __spi_queued_transfer(spi, message, false);
3441
3442 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3443 } else {
3444 status = spi_async_locked(spi, message);
3445 }
3446
3447 if (status == 0) {
3448 /* Push out the messages in the calling context if we
3449 * can.
3450 */
3451 if (ctlr->transfer == spi_queued_transfer) {
3452 SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3453 spi_sync_immediate);
3454 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3455 spi_sync_immediate);
3456 __spi_pump_messages(ctlr, false);
3457 }
3458
3459 wait_for_completion(&done);
3460 status = message->status;
3461 }
3462 message->context = NULL;
3463 return status;
3464}
3465
3466/**
3467 * spi_sync - blocking/synchronous SPI data transfers
3468 * @spi: device with which data will be exchanged
3469 * @message: describes the data transfers
3470 * Context: can sleep
3471 *
3472 * This call may only be used from a context that may sleep. The sleep
3473 * is non-interruptible, and has no timeout. Low-overhead controller
3474 * drivers may DMA directly into and out of the message buffers.
3475 *
3476 * Note that the SPI device's chip select is active during the message,
3477 * and then is normally disabled between messages. Drivers for some
3478 * frequently-used devices may want to minimize costs of selecting a chip,
3479 * by leaving it selected in anticipation that the next message will go
3480 * to the same chip. (That may increase power usage.)
3481 *
3482 * Also, the caller is guaranteeing that the memory associated with the
3483 * message will not be freed before this call returns.
3484 *
3485 * Return: zero on success, else a negative error code.
3486 */
3487int spi_sync(struct spi_device *spi, struct spi_message *message)
3488{
3489 int ret;
3490
3491 mutex_lock(&spi->controller->bus_lock_mutex);
3492 ret = __spi_sync(spi, message);
3493 mutex_unlock(&spi->controller->bus_lock_mutex);
3494
3495 return ret;
3496}
3497EXPORT_SYMBOL_GPL(spi_sync);
3498
3499/**
3500 * spi_sync_locked - version of spi_sync with exclusive bus usage
3501 * @spi: device with which data will be exchanged
3502 * @message: describes the data transfers
3503 * Context: can sleep
3504 *
3505 * This call may only be used from a context that may sleep. The sleep
3506 * is non-interruptible, and has no timeout. Low-overhead controller
3507 * drivers may DMA directly into and out of the message buffers.
3508 *
3509 * This call should be used by drivers that require exclusive access to the
3510 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3511 * be released by a spi_bus_unlock call when the exclusive access is over.
3512 *
3513 * Return: zero on success, else a negative error code.
3514 */
3515int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3516{
3517 return __spi_sync(spi, message);
3518}
3519EXPORT_SYMBOL_GPL(spi_sync_locked);
3520
3521/**
3522 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3523 * @ctlr: SPI bus master that should be locked for exclusive bus access
3524 * Context: can sleep
3525 *
3526 * This call may only be used from a context that may sleep. The sleep
3527 * is non-interruptible, and has no timeout.
3528 *
3529 * This call should be used by drivers that require exclusive access to the
3530 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3531 * exclusive access is over. Data transfer must be done by spi_sync_locked
3532 * and spi_async_locked calls when the SPI bus lock is held.
3533 *
3534 * Return: always zero.
3535 */
3536int spi_bus_lock(struct spi_controller *ctlr)
3537{
3538 unsigned long flags;
3539
3540 mutex_lock(&ctlr->bus_lock_mutex);
3541
3542 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3543 ctlr->bus_lock_flag = 1;
3544 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3545
3546 /* mutex remains locked until spi_bus_unlock is called */
3547
3548 return 0;
3549}
3550EXPORT_SYMBOL_GPL(spi_bus_lock);
3551
3552/**
3553 * spi_bus_unlock - release the lock for exclusive SPI bus usage
3554 * @ctlr: SPI bus master that was locked for exclusive bus access
3555 * Context: can sleep
3556 *
3557 * This call may only be used from a context that may sleep. The sleep
3558 * is non-interruptible, and has no timeout.
3559 *
3560 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3561 * call.
3562 *
3563 * Return: always zero.
3564 */
3565int spi_bus_unlock(struct spi_controller *ctlr)
3566{
3567 ctlr->bus_lock_flag = 0;
3568
3569 mutex_unlock(&ctlr->bus_lock_mutex);
3570
3571 return 0;
3572}
3573EXPORT_SYMBOL_GPL(spi_bus_unlock);
3574
3575/* portable code must never pass more than 32 bytes */
3576#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
3577
3578static u8 *buf;
3579
3580/**
3581 * spi_write_then_read - SPI synchronous write followed by read
3582 * @spi: device with which data will be exchanged
3583 * @txbuf: data to be written (need not be dma-safe)
3584 * @n_tx: size of txbuf, in bytes
3585 * @rxbuf: buffer into which data will be read (need not be dma-safe)
3586 * @n_rx: size of rxbuf, in bytes
3587 * Context: can sleep
3588 *
3589 * This performs a half duplex MicroWire style transaction with the
3590 * device, sending txbuf and then reading rxbuf. The return value
3591 * is zero for success, else a negative errno status code.
3592 * This call may only be used from a context that may sleep.
3593 *
3594 * Parameters to this routine are always copied using a small buffer;
3595 * portable code should never use this for more than 32 bytes.
3596 * Performance-sensitive or bulk transfer code should instead use
3597 * spi_{async,sync}() calls with dma-safe buffers.
3598 *
3599 * Return: zero on success, else a negative error code.
3600 */
3601int spi_write_then_read(struct spi_device *spi,
3602 const void *txbuf, unsigned n_tx,
3603 void *rxbuf, unsigned n_rx)
3604{
3605 static DEFINE_MUTEX(lock);
3606
3607 int status;
3608 struct spi_message message;
3609 struct spi_transfer x[2];
3610 u8 *local_buf;
3611
3612 /* Use preallocated DMA-safe buffer if we can. We can't avoid
3613 * copying here, (as a pure convenience thing), but we can
3614 * keep heap costs out of the hot path unless someone else is
3615 * using the pre-allocated buffer or the transfer is too large.
3616 */
3617 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3618 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3619 GFP_KERNEL | GFP_DMA);
3620 if (!local_buf)
3621 return -ENOMEM;
3622 } else {
3623 local_buf = buf;
3624 }
3625
3626 spi_message_init(&message);
3627 memset(x, 0, sizeof(x));
3628 if (n_tx) {
3629 x[0].len = n_tx;
3630 spi_message_add_tail(&x[0], &message);
3631 }
3632 if (n_rx) {
3633 x[1].len = n_rx;
3634 spi_message_add_tail(&x[1], &message);
3635 }
3636
3637 memcpy(local_buf, txbuf, n_tx);
3638 x[0].tx_buf = local_buf;
3639 x[1].rx_buf = local_buf + n_tx;
3640
3641 /* do the i/o */
3642 status = spi_sync(spi, &message);
3643 if (status == 0)
3644 memcpy(rxbuf, x[1].rx_buf, n_rx);
3645
3646 if (x[0].tx_buf == buf)
3647 mutex_unlock(&lock);
3648 else
3649 kfree(local_buf);
3650
3651 return status;
3652}
3653EXPORT_SYMBOL_GPL(spi_write_then_read);
3654
3655/*-------------------------------------------------------------------------*/
3656
3657#if IS_ENABLED(CONFIG_OF)
3658/* must call put_device() when done with returned spi_device device */
3659struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3660{
3661 struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
3662
3663 return dev ? to_spi_device(dev) : NULL;
3664}
3665EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3666#endif /* IS_ENABLED(CONFIG_OF) */
3667
3668#if IS_ENABLED(CONFIG_OF_DYNAMIC)
3669/* the spi controllers are not using spi_bus, so we find it with another way */
3670static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3671{
3672 struct device *dev;
3673
3674 dev = class_find_device_by_of_node(&spi_master_class, node);
3675 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3676 dev = class_find_device_by_of_node(&spi_slave_class, node);
3677 if (!dev)
3678 return NULL;
3679
3680 /* reference got in class_find_device */
3681 return container_of(dev, struct spi_controller, dev);
3682}
3683
3684static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3685 void *arg)
3686{
3687 struct of_reconfig_data *rd = arg;
3688 struct spi_controller *ctlr;
3689 struct spi_device *spi;
3690
3691 switch (of_reconfig_get_state_change(action, arg)) {
3692 case OF_RECONFIG_CHANGE_ADD:
3693 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3694 if (ctlr == NULL)
3695 return NOTIFY_OK; /* not for us */
3696
3697 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3698 put_device(&ctlr->dev);
3699 return NOTIFY_OK;
3700 }
3701
3702 spi = of_register_spi_device(ctlr, rd->dn);
3703 put_device(&ctlr->dev);
3704
3705 if (IS_ERR(spi)) {
3706 pr_err("%s: failed to create for '%pOF'\n",
3707 __func__, rd->dn);
3708 of_node_clear_flag(rd->dn, OF_POPULATED);
3709 return notifier_from_errno(PTR_ERR(spi));
3710 }
3711 break;
3712
3713 case OF_RECONFIG_CHANGE_REMOVE:
3714 /* already depopulated? */
3715 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3716 return NOTIFY_OK;
3717
3718 /* find our device by node */
3719 spi = of_find_spi_device_by_node(rd->dn);
3720 if (spi == NULL)
3721 return NOTIFY_OK; /* no? not meant for us */
3722
3723 /* unregister takes one ref away */
3724 spi_unregister_device(spi);
3725
3726 /* and put the reference of the find */
3727 put_device(&spi->dev);
3728 break;
3729 }
3730
3731 return NOTIFY_OK;
3732}
3733
3734static struct notifier_block spi_of_notifier = {
3735 .notifier_call = of_spi_notify,
3736};
3737#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3738extern struct notifier_block spi_of_notifier;
3739#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3740
3741#if IS_ENABLED(CONFIG_ACPI)
3742static int spi_acpi_controller_match(struct device *dev, const void *data)
3743{
3744 return ACPI_COMPANION(dev->parent) == data;
3745}
3746
3747static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3748{
3749 struct device *dev;
3750
3751 dev = class_find_device(&spi_master_class, NULL, adev,
3752 spi_acpi_controller_match);
3753 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3754 dev = class_find_device(&spi_slave_class, NULL, adev,
3755 spi_acpi_controller_match);
3756 if (!dev)
3757 return NULL;
3758
3759 return container_of(dev, struct spi_controller, dev);
3760}
3761
3762static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3763{
3764 struct device *dev;
3765
3766 dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
3767 return dev ? to_spi_device(dev) : NULL;
3768}
3769
3770static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3771 void *arg)
3772{
3773 struct acpi_device *adev = arg;
3774 struct spi_controller *ctlr;
3775 struct spi_device *spi;
3776
3777 switch (value) {
3778 case ACPI_RECONFIG_DEVICE_ADD:
3779 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3780 if (!ctlr)
3781 break;
3782
3783 acpi_register_spi_device(ctlr, adev);
3784 put_device(&ctlr->dev);
3785 break;
3786 case ACPI_RECONFIG_DEVICE_REMOVE:
3787 if (!acpi_device_enumerated(adev))
3788 break;
3789
3790 spi = acpi_spi_find_device_by_adev(adev);
3791 if (!spi)
3792 break;
3793
3794 spi_unregister_device(spi);
3795 put_device(&spi->dev);
3796 break;
3797 }
3798
3799 return NOTIFY_OK;
3800}
3801
3802static struct notifier_block spi_acpi_notifier = {
3803 .notifier_call = acpi_spi_notify,
3804};
3805#else
3806extern struct notifier_block spi_acpi_notifier;
3807#endif
3808
3809static int __init spi_init(void)
3810{
3811 int status;
3812
3813 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3814 if (!buf) {
3815 status = -ENOMEM;
3816 goto err0;
3817 }
3818
3819 status = bus_register(&spi_bus_type);
3820 if (status < 0)
3821 goto err1;
3822
3823 status = class_register(&spi_master_class);
3824 if (status < 0)
3825 goto err2;
3826
3827 if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3828 status = class_register(&spi_slave_class);
3829 if (status < 0)
3830 goto err3;
3831 }
3832
3833 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3834 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3835 if (IS_ENABLED(CONFIG_ACPI))
3836 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3837
3838 return 0;
3839
3840err3:
3841 class_unregister(&spi_master_class);
3842err2:
3843 bus_unregister(&spi_bus_type);
3844err1:
3845 kfree(buf);
3846 buf = NULL;
3847err0:
3848 return status;
3849}
3850
3851/* board_info is normally registered in arch_initcall(),
3852 * but even essential drivers wait till later
3853 *
3854 * REVISIT only boardinfo really needs static linking. the rest (device and
3855 * driver registration) _could_ be dynamically linked (modular) ... costs
3856 * include needing to have boardinfo data structures be much more public.
3857 */
3858postcore_initcall(spi_init);