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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/mutex.h>
28#include <linux/of_device.h>
29#include <linux/of_irq.h>
30#include <linux/slab.h>
31#include <linux/mod_devicetable.h>
32#include <linux/spi/spi.h>
33#include <linux/pm_runtime.h>
34#include <linux/export.h>
35#include <linux/sched.h>
36#include <linux/delay.h>
37#include <linux/kthread.h>
38
39static void spidev_release(struct device *dev)
40{
41 struct spi_device *spi = to_spi_device(dev);
42
43 /* spi masters may cleanup for released devices */
44 if (spi->master->cleanup)
45 spi->master->cleanup(spi);
46
47 spi_master_put(spi->master);
48 kfree(spi);
49}
50
51static ssize_t
52modalias_show(struct device *dev, struct device_attribute *a, char *buf)
53{
54 const struct spi_device *spi = to_spi_device(dev);
55
56 return sprintf(buf, "%s\n", spi->modalias);
57}
58
59static struct device_attribute spi_dev_attrs[] = {
60 __ATTR_RO(modalias),
61 __ATTR_NULL,
62};
63
64/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
65 * and the sysfs version makes coldplug work too.
66 */
67
68static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
69 const struct spi_device *sdev)
70{
71 while (id->name[0]) {
72 if (!strcmp(sdev->modalias, id->name))
73 return id;
74 id++;
75 }
76 return NULL;
77}
78
79const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
80{
81 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
82
83 return spi_match_id(sdrv->id_table, sdev);
84}
85EXPORT_SYMBOL_GPL(spi_get_device_id);
86
87static int spi_match_device(struct device *dev, struct device_driver *drv)
88{
89 const struct spi_device *spi = to_spi_device(dev);
90 const struct spi_driver *sdrv = to_spi_driver(drv);
91
92 /* Attempt an OF style match */
93 if (of_driver_match_device(dev, drv))
94 return 1;
95
96 if (sdrv->id_table)
97 return !!spi_match_id(sdrv->id_table, spi);
98
99 return strcmp(spi->modalias, drv->name) == 0;
100}
101
102static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
103{
104 const struct spi_device *spi = to_spi_device(dev);
105
106 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
107 return 0;
108}
109
110#ifdef CONFIG_PM_SLEEP
111static int spi_legacy_suspend(struct device *dev, pm_message_t message)
112{
113 int value = 0;
114 struct spi_driver *drv = to_spi_driver(dev->driver);
115
116 /* suspend will stop irqs and dma; no more i/o */
117 if (drv) {
118 if (drv->suspend)
119 value = drv->suspend(to_spi_device(dev), message);
120 else
121 dev_dbg(dev, "... can't suspend\n");
122 }
123 return value;
124}
125
126static int spi_legacy_resume(struct device *dev)
127{
128 int value = 0;
129 struct spi_driver *drv = to_spi_driver(dev->driver);
130
131 /* resume may restart the i/o queue */
132 if (drv) {
133 if (drv->resume)
134 value = drv->resume(to_spi_device(dev));
135 else
136 dev_dbg(dev, "... can't resume\n");
137 }
138 return value;
139}
140
141static int spi_pm_suspend(struct device *dev)
142{
143 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
144
145 if (pm)
146 return pm_generic_suspend(dev);
147 else
148 return spi_legacy_suspend(dev, PMSG_SUSPEND);
149}
150
151static int spi_pm_resume(struct device *dev)
152{
153 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
154
155 if (pm)
156 return pm_generic_resume(dev);
157 else
158 return spi_legacy_resume(dev);
159}
160
161static int spi_pm_freeze(struct device *dev)
162{
163 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
164
165 if (pm)
166 return pm_generic_freeze(dev);
167 else
168 return spi_legacy_suspend(dev, PMSG_FREEZE);
169}
170
171static int spi_pm_thaw(struct device *dev)
172{
173 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
174
175 if (pm)
176 return pm_generic_thaw(dev);
177 else
178 return spi_legacy_resume(dev);
179}
180
181static int spi_pm_poweroff(struct device *dev)
182{
183 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
184
185 if (pm)
186 return pm_generic_poweroff(dev);
187 else
188 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
189}
190
191static int spi_pm_restore(struct device *dev)
192{
193 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
194
195 if (pm)
196 return pm_generic_restore(dev);
197 else
198 return spi_legacy_resume(dev);
199}
200#else
201#define spi_pm_suspend NULL
202#define spi_pm_resume NULL
203#define spi_pm_freeze NULL
204#define spi_pm_thaw NULL
205#define spi_pm_poweroff NULL
206#define spi_pm_restore NULL
207#endif
208
209static const struct dev_pm_ops spi_pm = {
210 .suspend = spi_pm_suspend,
211 .resume = spi_pm_resume,
212 .freeze = spi_pm_freeze,
213 .thaw = spi_pm_thaw,
214 .poweroff = spi_pm_poweroff,
215 .restore = spi_pm_restore,
216 SET_RUNTIME_PM_OPS(
217 pm_generic_runtime_suspend,
218 pm_generic_runtime_resume,
219 pm_generic_runtime_idle
220 )
221};
222
223struct bus_type spi_bus_type = {
224 .name = "spi",
225 .dev_attrs = spi_dev_attrs,
226 .match = spi_match_device,
227 .uevent = spi_uevent,
228 .pm = &spi_pm,
229};
230EXPORT_SYMBOL_GPL(spi_bus_type);
231
232
233static int spi_drv_probe(struct device *dev)
234{
235 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
236
237 return sdrv->probe(to_spi_device(dev));
238}
239
240static int spi_drv_remove(struct device *dev)
241{
242 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
243
244 return sdrv->remove(to_spi_device(dev));
245}
246
247static void spi_drv_shutdown(struct device *dev)
248{
249 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
250
251 sdrv->shutdown(to_spi_device(dev));
252}
253
254/**
255 * spi_register_driver - register a SPI driver
256 * @sdrv: the driver to register
257 * Context: can sleep
258 */
259int spi_register_driver(struct spi_driver *sdrv)
260{
261 sdrv->driver.bus = &spi_bus_type;
262 if (sdrv->probe)
263 sdrv->driver.probe = spi_drv_probe;
264 if (sdrv->remove)
265 sdrv->driver.remove = spi_drv_remove;
266 if (sdrv->shutdown)
267 sdrv->driver.shutdown = spi_drv_shutdown;
268 return driver_register(&sdrv->driver);
269}
270EXPORT_SYMBOL_GPL(spi_register_driver);
271
272/*-------------------------------------------------------------------------*/
273
274/* SPI devices should normally not be created by SPI device drivers; that
275 * would make them board-specific. Similarly with SPI master drivers.
276 * Device registration normally goes into like arch/.../mach.../board-YYY.c
277 * with other readonly (flashable) information about mainboard devices.
278 */
279
280struct boardinfo {
281 struct list_head list;
282 struct spi_board_info board_info;
283};
284
285static LIST_HEAD(board_list);
286static LIST_HEAD(spi_master_list);
287
288/*
289 * Used to protect add/del opertion for board_info list and
290 * spi_master list, and their matching process
291 */
292static DEFINE_MUTEX(board_lock);
293
294/**
295 * spi_alloc_device - Allocate a new SPI device
296 * @master: Controller to which device is connected
297 * Context: can sleep
298 *
299 * Allows a driver to allocate and initialize a spi_device without
300 * registering it immediately. This allows a driver to directly
301 * fill the spi_device with device parameters before calling
302 * spi_add_device() on it.
303 *
304 * Caller is responsible to call spi_add_device() on the returned
305 * spi_device structure to add it to the SPI master. If the caller
306 * needs to discard the spi_device without adding it, then it should
307 * call spi_dev_put() on it.
308 *
309 * Returns a pointer to the new device, or NULL.
310 */
311struct spi_device *spi_alloc_device(struct spi_master *master)
312{
313 struct spi_device *spi;
314 struct device *dev = master->dev.parent;
315
316 if (!spi_master_get(master))
317 return NULL;
318
319 spi = kzalloc(sizeof *spi, GFP_KERNEL);
320 if (!spi) {
321 dev_err(dev, "cannot alloc spi_device\n");
322 spi_master_put(master);
323 return NULL;
324 }
325
326 spi->master = master;
327 spi->dev.parent = &master->dev;
328 spi->dev.bus = &spi_bus_type;
329 spi->dev.release = spidev_release;
330 device_initialize(&spi->dev);
331 return spi;
332}
333EXPORT_SYMBOL_GPL(spi_alloc_device);
334
335/**
336 * spi_add_device - Add spi_device allocated with spi_alloc_device
337 * @spi: spi_device to register
338 *
339 * Companion function to spi_alloc_device. Devices allocated with
340 * spi_alloc_device can be added onto the spi bus with this function.
341 *
342 * Returns 0 on success; negative errno on failure
343 */
344int spi_add_device(struct spi_device *spi)
345{
346 static DEFINE_MUTEX(spi_add_lock);
347 struct device *dev = spi->master->dev.parent;
348 struct device *d;
349 int status;
350
351 /* Chipselects are numbered 0..max; validate. */
352 if (spi->chip_select >= spi->master->num_chipselect) {
353 dev_err(dev, "cs%d >= max %d\n",
354 spi->chip_select,
355 spi->master->num_chipselect);
356 return -EINVAL;
357 }
358
359 /* Set the bus ID string */
360 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
361 spi->chip_select);
362
363
364 /* We need to make sure there's no other device with this
365 * chipselect **BEFORE** we call setup(), else we'll trash
366 * its configuration. Lock against concurrent add() calls.
367 */
368 mutex_lock(&spi_add_lock);
369
370 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
371 if (d != NULL) {
372 dev_err(dev, "chipselect %d already in use\n",
373 spi->chip_select);
374 put_device(d);
375 status = -EBUSY;
376 goto done;
377 }
378
379 /* Drivers may modify this initial i/o setup, but will
380 * normally rely on the device being setup. Devices
381 * using SPI_CS_HIGH can't coexist well otherwise...
382 */
383 status = spi_setup(spi);
384 if (status < 0) {
385 dev_err(dev, "can't setup %s, status %d\n",
386 dev_name(&spi->dev), status);
387 goto done;
388 }
389
390 /* Device may be bound to an active driver when this returns */
391 status = device_add(&spi->dev);
392 if (status < 0)
393 dev_err(dev, "can't add %s, status %d\n",
394 dev_name(&spi->dev), status);
395 else
396 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
397
398done:
399 mutex_unlock(&spi_add_lock);
400 return status;
401}
402EXPORT_SYMBOL_GPL(spi_add_device);
403
404/**
405 * spi_new_device - instantiate one new SPI device
406 * @master: Controller to which device is connected
407 * @chip: Describes the SPI device
408 * Context: can sleep
409 *
410 * On typical mainboards, this is purely internal; and it's not needed
411 * after board init creates the hard-wired devices. Some development
412 * platforms may not be able to use spi_register_board_info though, and
413 * this is exported so that for example a USB or parport based adapter
414 * driver could add devices (which it would learn about out-of-band).
415 *
416 * Returns the new device, or NULL.
417 */
418struct spi_device *spi_new_device(struct spi_master *master,
419 struct spi_board_info *chip)
420{
421 struct spi_device *proxy;
422 int status;
423
424 /* NOTE: caller did any chip->bus_num checks necessary.
425 *
426 * Also, unless we change the return value convention to use
427 * error-or-pointer (not NULL-or-pointer), troubleshootability
428 * suggests syslogged diagnostics are best here (ugh).
429 */
430
431 proxy = spi_alloc_device(master);
432 if (!proxy)
433 return NULL;
434
435 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
436
437 proxy->chip_select = chip->chip_select;
438 proxy->max_speed_hz = chip->max_speed_hz;
439 proxy->mode = chip->mode;
440 proxy->irq = chip->irq;
441 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
442 proxy->dev.platform_data = (void *) chip->platform_data;
443 proxy->controller_data = chip->controller_data;
444 proxy->controller_state = NULL;
445
446 status = spi_add_device(proxy);
447 if (status < 0) {
448 spi_dev_put(proxy);
449 return NULL;
450 }
451
452 return proxy;
453}
454EXPORT_SYMBOL_GPL(spi_new_device);
455
456static void spi_match_master_to_boardinfo(struct spi_master *master,
457 struct spi_board_info *bi)
458{
459 struct spi_device *dev;
460
461 if (master->bus_num != bi->bus_num)
462 return;
463
464 dev = spi_new_device(master, bi);
465 if (!dev)
466 dev_err(master->dev.parent, "can't create new device for %s\n",
467 bi->modalias);
468}
469
470/**
471 * spi_register_board_info - register SPI devices for a given board
472 * @info: array of chip descriptors
473 * @n: how many descriptors are provided
474 * Context: can sleep
475 *
476 * Board-specific early init code calls this (probably during arch_initcall)
477 * with segments of the SPI device table. Any device nodes are created later,
478 * after the relevant parent SPI controller (bus_num) is defined. We keep
479 * this table of devices forever, so that reloading a controller driver will
480 * not make Linux forget about these hard-wired devices.
481 *
482 * Other code can also call this, e.g. a particular add-on board might provide
483 * SPI devices through its expansion connector, so code initializing that board
484 * would naturally declare its SPI devices.
485 *
486 * The board info passed can safely be __initdata ... but be careful of
487 * any embedded pointers (platform_data, etc), they're copied as-is.
488 */
489int __devinit
490spi_register_board_info(struct spi_board_info const *info, unsigned n)
491{
492 struct boardinfo *bi;
493 int i;
494
495 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
496 if (!bi)
497 return -ENOMEM;
498
499 for (i = 0; i < n; i++, bi++, info++) {
500 struct spi_master *master;
501
502 memcpy(&bi->board_info, info, sizeof(*info));
503 mutex_lock(&board_lock);
504 list_add_tail(&bi->list, &board_list);
505 list_for_each_entry(master, &spi_master_list, list)
506 spi_match_master_to_boardinfo(master, &bi->board_info);
507 mutex_unlock(&board_lock);
508 }
509
510 return 0;
511}
512
513/*-------------------------------------------------------------------------*/
514
515/**
516 * spi_pump_messages - kthread work function which processes spi message queue
517 * @work: pointer to kthread work struct contained in the master struct
518 *
519 * This function checks if there is any spi message in the queue that
520 * needs processing and if so call out to the driver to initialize hardware
521 * and transfer each message.
522 *
523 */
524static void spi_pump_messages(struct kthread_work *work)
525{
526 struct spi_master *master =
527 container_of(work, struct spi_master, pump_messages);
528 unsigned long flags;
529 bool was_busy = false;
530 int ret;
531
532 /* Lock queue and check for queue work */
533 spin_lock_irqsave(&master->queue_lock, flags);
534 if (list_empty(&master->queue) || !master->running) {
535 if (master->busy && master->unprepare_transfer_hardware) {
536 ret = master->unprepare_transfer_hardware(master);
537 if (ret) {
538 spin_unlock_irqrestore(&master->queue_lock, flags);
539 dev_err(&master->dev,
540 "failed to unprepare transfer hardware\n");
541 return;
542 }
543 }
544 master->busy = false;
545 spin_unlock_irqrestore(&master->queue_lock, flags);
546 return;
547 }
548
549 /* Make sure we are not already running a message */
550 if (master->cur_msg) {
551 spin_unlock_irqrestore(&master->queue_lock, flags);
552 return;
553 }
554 /* Extract head of queue */
555 master->cur_msg =
556 list_entry(master->queue.next, struct spi_message, queue);
557
558 list_del_init(&master->cur_msg->queue);
559 if (master->busy)
560 was_busy = true;
561 else
562 master->busy = true;
563 spin_unlock_irqrestore(&master->queue_lock, flags);
564
565 if (!was_busy && master->prepare_transfer_hardware) {
566 ret = master->prepare_transfer_hardware(master);
567 if (ret) {
568 dev_err(&master->dev,
569 "failed to prepare transfer hardware\n");
570 return;
571 }
572 }
573
574 ret = master->transfer_one_message(master, master->cur_msg);
575 if (ret) {
576 dev_err(&master->dev,
577 "failed to transfer one message from queue\n");
578 return;
579 }
580}
581
582static int spi_init_queue(struct spi_master *master)
583{
584 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
585
586 INIT_LIST_HEAD(&master->queue);
587 spin_lock_init(&master->queue_lock);
588
589 master->running = false;
590 master->busy = false;
591
592 init_kthread_worker(&master->kworker);
593 master->kworker_task = kthread_run(kthread_worker_fn,
594 &master->kworker,
595 dev_name(&master->dev));
596 if (IS_ERR(master->kworker_task)) {
597 dev_err(&master->dev, "failed to create message pump task\n");
598 return -ENOMEM;
599 }
600 init_kthread_work(&master->pump_messages, spi_pump_messages);
601
602 /*
603 * Master config will indicate if this controller should run the
604 * message pump with high (realtime) priority to reduce the transfer
605 * latency on the bus by minimising the delay between a transfer
606 * request and the scheduling of the message pump thread. Without this
607 * setting the message pump thread will remain at default priority.
608 */
609 if (master->rt) {
610 dev_info(&master->dev,
611 "will run message pump with realtime priority\n");
612 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
613 }
614
615 return 0;
616}
617
618/**
619 * spi_get_next_queued_message() - called by driver to check for queued
620 * messages
621 * @master: the master to check for queued messages
622 *
623 * If there are more messages in the queue, the next message is returned from
624 * this call.
625 */
626struct spi_message *spi_get_next_queued_message(struct spi_master *master)
627{
628 struct spi_message *next;
629 unsigned long flags;
630
631 /* get a pointer to the next message, if any */
632 spin_lock_irqsave(&master->queue_lock, flags);
633 if (list_empty(&master->queue))
634 next = NULL;
635 else
636 next = list_entry(master->queue.next,
637 struct spi_message, queue);
638 spin_unlock_irqrestore(&master->queue_lock, flags);
639
640 return next;
641}
642EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
643
644/**
645 * spi_finalize_current_message() - the current message is complete
646 * @master: the master to return the message to
647 *
648 * Called by the driver to notify the core that the message in the front of the
649 * queue is complete and can be removed from the queue.
650 */
651void spi_finalize_current_message(struct spi_master *master)
652{
653 struct spi_message *mesg;
654 unsigned long flags;
655
656 spin_lock_irqsave(&master->queue_lock, flags);
657 mesg = master->cur_msg;
658 master->cur_msg = NULL;
659
660 queue_kthread_work(&master->kworker, &master->pump_messages);
661 spin_unlock_irqrestore(&master->queue_lock, flags);
662
663 mesg->state = NULL;
664 if (mesg->complete)
665 mesg->complete(mesg->context);
666}
667EXPORT_SYMBOL_GPL(spi_finalize_current_message);
668
669static int spi_start_queue(struct spi_master *master)
670{
671 unsigned long flags;
672
673 spin_lock_irqsave(&master->queue_lock, flags);
674
675 if (master->running || master->busy) {
676 spin_unlock_irqrestore(&master->queue_lock, flags);
677 return -EBUSY;
678 }
679
680 master->running = true;
681 master->cur_msg = NULL;
682 spin_unlock_irqrestore(&master->queue_lock, flags);
683
684 queue_kthread_work(&master->kworker, &master->pump_messages);
685
686 return 0;
687}
688
689static int spi_stop_queue(struct spi_master *master)
690{
691 unsigned long flags;
692 unsigned limit = 500;
693 int ret = 0;
694
695 spin_lock_irqsave(&master->queue_lock, flags);
696
697 /*
698 * This is a bit lame, but is optimized for the common execution path.
699 * A wait_queue on the master->busy could be used, but then the common
700 * execution path (pump_messages) would be required to call wake_up or
701 * friends on every SPI message. Do this instead.
702 */
703 while ((!list_empty(&master->queue) || master->busy) && limit--) {
704 spin_unlock_irqrestore(&master->queue_lock, flags);
705 msleep(10);
706 spin_lock_irqsave(&master->queue_lock, flags);
707 }
708
709 if (!list_empty(&master->queue) || master->busy)
710 ret = -EBUSY;
711 else
712 master->running = false;
713
714 spin_unlock_irqrestore(&master->queue_lock, flags);
715
716 if (ret) {
717 dev_warn(&master->dev,
718 "could not stop message queue\n");
719 return ret;
720 }
721 return ret;
722}
723
724static int spi_destroy_queue(struct spi_master *master)
725{
726 int ret;
727
728 ret = spi_stop_queue(master);
729
730 /*
731 * flush_kthread_worker will block until all work is done.
732 * If the reason that stop_queue timed out is that the work will never
733 * finish, then it does no good to call flush/stop thread, so
734 * return anyway.
735 */
736 if (ret) {
737 dev_err(&master->dev, "problem destroying queue\n");
738 return ret;
739 }
740
741 flush_kthread_worker(&master->kworker);
742 kthread_stop(master->kworker_task);
743
744 return 0;
745}
746
747/**
748 * spi_queued_transfer - transfer function for queued transfers
749 * @spi: spi device which is requesting transfer
750 * @msg: spi message which is to handled is queued to driver queue
751 */
752static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
753{
754 struct spi_master *master = spi->master;
755 unsigned long flags;
756
757 spin_lock_irqsave(&master->queue_lock, flags);
758
759 if (!master->running) {
760 spin_unlock_irqrestore(&master->queue_lock, flags);
761 return -ESHUTDOWN;
762 }
763 msg->actual_length = 0;
764 msg->status = -EINPROGRESS;
765
766 list_add_tail(&msg->queue, &master->queue);
767 if (master->running && !master->busy)
768 queue_kthread_work(&master->kworker, &master->pump_messages);
769
770 spin_unlock_irqrestore(&master->queue_lock, flags);
771 return 0;
772}
773
774static int spi_master_initialize_queue(struct spi_master *master)
775{
776 int ret;
777
778 master->queued = true;
779 master->transfer = spi_queued_transfer;
780
781 /* Initialize and start queue */
782 ret = spi_init_queue(master);
783 if (ret) {
784 dev_err(&master->dev, "problem initializing queue\n");
785 goto err_init_queue;
786 }
787 ret = spi_start_queue(master);
788 if (ret) {
789 dev_err(&master->dev, "problem starting queue\n");
790 goto err_start_queue;
791 }
792
793 return 0;
794
795err_start_queue:
796err_init_queue:
797 spi_destroy_queue(master);
798 return ret;
799}
800
801/*-------------------------------------------------------------------------*/
802
803#if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
804/**
805 * of_register_spi_devices() - Register child devices onto the SPI bus
806 * @master: Pointer to spi_master device
807 *
808 * Registers an spi_device for each child node of master node which has a 'reg'
809 * property.
810 */
811static void of_register_spi_devices(struct spi_master *master)
812{
813 struct spi_device *spi;
814 struct device_node *nc;
815 const __be32 *prop;
816 int rc;
817 int len;
818
819 if (!master->dev.of_node)
820 return;
821
822 for_each_child_of_node(master->dev.of_node, nc) {
823 /* Alloc an spi_device */
824 spi = spi_alloc_device(master);
825 if (!spi) {
826 dev_err(&master->dev, "spi_device alloc error for %s\n",
827 nc->full_name);
828 spi_dev_put(spi);
829 continue;
830 }
831
832 /* Select device driver */
833 if (of_modalias_node(nc, spi->modalias,
834 sizeof(spi->modalias)) < 0) {
835 dev_err(&master->dev, "cannot find modalias for %s\n",
836 nc->full_name);
837 spi_dev_put(spi);
838 continue;
839 }
840
841 /* Device address */
842 prop = of_get_property(nc, "reg", &len);
843 if (!prop || len < sizeof(*prop)) {
844 dev_err(&master->dev, "%s has no 'reg' property\n",
845 nc->full_name);
846 spi_dev_put(spi);
847 continue;
848 }
849 spi->chip_select = be32_to_cpup(prop);
850
851 /* Mode (clock phase/polarity/etc.) */
852 if (of_find_property(nc, "spi-cpha", NULL))
853 spi->mode |= SPI_CPHA;
854 if (of_find_property(nc, "spi-cpol", NULL))
855 spi->mode |= SPI_CPOL;
856 if (of_find_property(nc, "spi-cs-high", NULL))
857 spi->mode |= SPI_CS_HIGH;
858
859 /* Device speed */
860 prop = of_get_property(nc, "spi-max-frequency", &len);
861 if (!prop || len < sizeof(*prop)) {
862 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
863 nc->full_name);
864 spi_dev_put(spi);
865 continue;
866 }
867 spi->max_speed_hz = be32_to_cpup(prop);
868
869 /* IRQ */
870 spi->irq = irq_of_parse_and_map(nc, 0);
871
872 /* Store a pointer to the node in the device structure */
873 of_node_get(nc);
874 spi->dev.of_node = nc;
875
876 /* Register the new device */
877 request_module(spi->modalias);
878 rc = spi_add_device(spi);
879 if (rc) {
880 dev_err(&master->dev, "spi_device register error %s\n",
881 nc->full_name);
882 spi_dev_put(spi);
883 }
884
885 }
886}
887#else
888static void of_register_spi_devices(struct spi_master *master) { }
889#endif
890
891static void spi_master_release(struct device *dev)
892{
893 struct spi_master *master;
894
895 master = container_of(dev, struct spi_master, dev);
896 kfree(master);
897}
898
899static struct class spi_master_class = {
900 .name = "spi_master",
901 .owner = THIS_MODULE,
902 .dev_release = spi_master_release,
903};
904
905
906
907/**
908 * spi_alloc_master - allocate SPI master controller
909 * @dev: the controller, possibly using the platform_bus
910 * @size: how much zeroed driver-private data to allocate; the pointer to this
911 * memory is in the driver_data field of the returned device,
912 * accessible with spi_master_get_devdata().
913 * Context: can sleep
914 *
915 * This call is used only by SPI master controller drivers, which are the
916 * only ones directly touching chip registers. It's how they allocate
917 * an spi_master structure, prior to calling spi_register_master().
918 *
919 * This must be called from context that can sleep. It returns the SPI
920 * master structure on success, else NULL.
921 *
922 * The caller is responsible for assigning the bus number and initializing
923 * the master's methods before calling spi_register_master(); and (after errors
924 * adding the device) calling spi_master_put() and kfree() to prevent a memory
925 * leak.
926 */
927struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
928{
929 struct spi_master *master;
930
931 if (!dev)
932 return NULL;
933
934 master = kzalloc(size + sizeof *master, GFP_KERNEL);
935 if (!master)
936 return NULL;
937
938 device_initialize(&master->dev);
939 master->bus_num = -1;
940 master->num_chipselect = 1;
941 master->dev.class = &spi_master_class;
942 master->dev.parent = get_device(dev);
943 spi_master_set_devdata(master, &master[1]);
944
945 return master;
946}
947EXPORT_SYMBOL_GPL(spi_alloc_master);
948
949/**
950 * spi_register_master - register SPI master controller
951 * @master: initialized master, originally from spi_alloc_master()
952 * Context: can sleep
953 *
954 * SPI master controllers connect to their drivers using some non-SPI bus,
955 * such as the platform bus. The final stage of probe() in that code
956 * includes calling spi_register_master() to hook up to this SPI bus glue.
957 *
958 * SPI controllers use board specific (often SOC specific) bus numbers,
959 * and board-specific addressing for SPI devices combines those numbers
960 * with chip select numbers. Since SPI does not directly support dynamic
961 * device identification, boards need configuration tables telling which
962 * chip is at which address.
963 *
964 * This must be called from context that can sleep. It returns zero on
965 * success, else a negative error code (dropping the master's refcount).
966 * After a successful return, the caller is responsible for calling
967 * spi_unregister_master().
968 */
969int spi_register_master(struct spi_master *master)
970{
971 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
972 struct device *dev = master->dev.parent;
973 struct boardinfo *bi;
974 int status = -ENODEV;
975 int dynamic = 0;
976
977 if (!dev)
978 return -ENODEV;
979
980 /* even if it's just one always-selected device, there must
981 * be at least one chipselect
982 */
983 if (master->num_chipselect == 0)
984 return -EINVAL;
985
986 /* convention: dynamically assigned bus IDs count down from the max */
987 if (master->bus_num < 0) {
988 /* FIXME switch to an IDR based scheme, something like
989 * I2C now uses, so we can't run out of "dynamic" IDs
990 */
991 master->bus_num = atomic_dec_return(&dyn_bus_id);
992 dynamic = 1;
993 }
994
995 spin_lock_init(&master->bus_lock_spinlock);
996 mutex_init(&master->bus_lock_mutex);
997 master->bus_lock_flag = 0;
998
999 /* register the device, then userspace will see it.
1000 * registration fails if the bus ID is in use.
1001 */
1002 dev_set_name(&master->dev, "spi%u", master->bus_num);
1003 status = device_add(&master->dev);
1004 if (status < 0)
1005 goto done;
1006 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1007 dynamic ? " (dynamic)" : "");
1008
1009 /* If we're using a queued driver, start the queue */
1010 if (master->transfer)
1011 dev_info(dev, "master is unqueued, this is deprecated\n");
1012 else {
1013 status = spi_master_initialize_queue(master);
1014 if (status) {
1015 device_unregister(&master->dev);
1016 goto done;
1017 }
1018 }
1019
1020 mutex_lock(&board_lock);
1021 list_add_tail(&master->list, &spi_master_list);
1022 list_for_each_entry(bi, &board_list, list)
1023 spi_match_master_to_boardinfo(master, &bi->board_info);
1024 mutex_unlock(&board_lock);
1025
1026 /* Register devices from the device tree */
1027 of_register_spi_devices(master);
1028done:
1029 return status;
1030}
1031EXPORT_SYMBOL_GPL(spi_register_master);
1032
1033static int __unregister(struct device *dev, void *null)
1034{
1035 spi_unregister_device(to_spi_device(dev));
1036 return 0;
1037}
1038
1039/**
1040 * spi_unregister_master - unregister SPI master controller
1041 * @master: the master being unregistered
1042 * Context: can sleep
1043 *
1044 * This call is used only by SPI master controller drivers, which are the
1045 * only ones directly touching chip registers.
1046 *
1047 * This must be called from context that can sleep.
1048 */
1049void spi_unregister_master(struct spi_master *master)
1050{
1051 int dummy;
1052
1053 if (master->queued) {
1054 if (spi_destroy_queue(master))
1055 dev_err(&master->dev, "queue remove failed\n");
1056 }
1057
1058 mutex_lock(&board_lock);
1059 list_del(&master->list);
1060 mutex_unlock(&board_lock);
1061
1062 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1063 device_unregister(&master->dev);
1064}
1065EXPORT_SYMBOL_GPL(spi_unregister_master);
1066
1067int spi_master_suspend(struct spi_master *master)
1068{
1069 int ret;
1070
1071 /* Basically no-ops for non-queued masters */
1072 if (!master->queued)
1073 return 0;
1074
1075 ret = spi_stop_queue(master);
1076 if (ret)
1077 dev_err(&master->dev, "queue stop failed\n");
1078
1079 return ret;
1080}
1081EXPORT_SYMBOL_GPL(spi_master_suspend);
1082
1083int spi_master_resume(struct spi_master *master)
1084{
1085 int ret;
1086
1087 if (!master->queued)
1088 return 0;
1089
1090 ret = spi_start_queue(master);
1091 if (ret)
1092 dev_err(&master->dev, "queue restart failed\n");
1093
1094 return ret;
1095}
1096EXPORT_SYMBOL_GPL(spi_master_resume);
1097
1098static int __spi_master_match(struct device *dev, void *data)
1099{
1100 struct spi_master *m;
1101 u16 *bus_num = data;
1102
1103 m = container_of(dev, struct spi_master, dev);
1104 return m->bus_num == *bus_num;
1105}
1106
1107/**
1108 * spi_busnum_to_master - look up master associated with bus_num
1109 * @bus_num: the master's bus number
1110 * Context: can sleep
1111 *
1112 * This call may be used with devices that are registered after
1113 * arch init time. It returns a refcounted pointer to the relevant
1114 * spi_master (which the caller must release), or NULL if there is
1115 * no such master registered.
1116 */
1117struct spi_master *spi_busnum_to_master(u16 bus_num)
1118{
1119 struct device *dev;
1120 struct spi_master *master = NULL;
1121
1122 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1123 __spi_master_match);
1124 if (dev)
1125 master = container_of(dev, struct spi_master, dev);
1126 /* reference got in class_find_device */
1127 return master;
1128}
1129EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1130
1131
1132/*-------------------------------------------------------------------------*/
1133
1134/* Core methods for SPI master protocol drivers. Some of the
1135 * other core methods are currently defined as inline functions.
1136 */
1137
1138/**
1139 * spi_setup - setup SPI mode and clock rate
1140 * @spi: the device whose settings are being modified
1141 * Context: can sleep, and no requests are queued to the device
1142 *
1143 * SPI protocol drivers may need to update the transfer mode if the
1144 * device doesn't work with its default. They may likewise need
1145 * to update clock rates or word sizes from initial values. This function
1146 * changes those settings, and must be called from a context that can sleep.
1147 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1148 * effect the next time the device is selected and data is transferred to
1149 * or from it. When this function returns, the spi device is deselected.
1150 *
1151 * Note that this call will fail if the protocol driver specifies an option
1152 * that the underlying controller or its driver does not support. For
1153 * example, not all hardware supports wire transfers using nine bit words,
1154 * LSB-first wire encoding, or active-high chipselects.
1155 */
1156int spi_setup(struct spi_device *spi)
1157{
1158 unsigned bad_bits;
1159 int status;
1160
1161 /* help drivers fail *cleanly* when they need options
1162 * that aren't supported with their current master
1163 */
1164 bad_bits = spi->mode & ~spi->master->mode_bits;
1165 if (bad_bits) {
1166 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1167 bad_bits);
1168 return -EINVAL;
1169 }
1170
1171 if (!spi->bits_per_word)
1172 spi->bits_per_word = 8;
1173
1174 status = spi->master->setup(spi);
1175
1176 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1177 "%u bits/w, %u Hz max --> %d\n",
1178 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1179 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1180 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1181 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1182 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1183 spi->bits_per_word, spi->max_speed_hz,
1184 status);
1185
1186 return status;
1187}
1188EXPORT_SYMBOL_GPL(spi_setup);
1189
1190static int __spi_async(struct spi_device *spi, struct spi_message *message)
1191{
1192 struct spi_master *master = spi->master;
1193
1194 /* Half-duplex links include original MicroWire, and ones with
1195 * only one data pin like SPI_3WIRE (switches direction) or where
1196 * either MOSI or MISO is missing. They can also be caused by
1197 * software limitations.
1198 */
1199 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1200 || (spi->mode & SPI_3WIRE)) {
1201 struct spi_transfer *xfer;
1202 unsigned flags = master->flags;
1203
1204 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1205 if (xfer->rx_buf && xfer->tx_buf)
1206 return -EINVAL;
1207 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1208 return -EINVAL;
1209 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1210 return -EINVAL;
1211 }
1212 }
1213
1214 message->spi = spi;
1215 message->status = -EINPROGRESS;
1216 return master->transfer(spi, message);
1217}
1218
1219/**
1220 * spi_async - asynchronous SPI transfer
1221 * @spi: device with which data will be exchanged
1222 * @message: describes the data transfers, including completion callback
1223 * Context: any (irqs may be blocked, etc)
1224 *
1225 * This call may be used in_irq and other contexts which can't sleep,
1226 * as well as from task contexts which can sleep.
1227 *
1228 * The completion callback is invoked in a context which can't sleep.
1229 * Before that invocation, the value of message->status is undefined.
1230 * When the callback is issued, message->status holds either zero (to
1231 * indicate complete success) or a negative error code. After that
1232 * callback returns, the driver which issued the transfer request may
1233 * deallocate the associated memory; it's no longer in use by any SPI
1234 * core or controller driver code.
1235 *
1236 * Note that although all messages to a spi_device are handled in
1237 * FIFO order, messages may go to different devices in other orders.
1238 * Some device might be higher priority, or have various "hard" access
1239 * time requirements, for example.
1240 *
1241 * On detection of any fault during the transfer, processing of
1242 * the entire message is aborted, and the device is deselected.
1243 * Until returning from the associated message completion callback,
1244 * no other spi_message queued to that device will be processed.
1245 * (This rule applies equally to all the synchronous transfer calls,
1246 * which are wrappers around this core asynchronous primitive.)
1247 */
1248int spi_async(struct spi_device *spi, struct spi_message *message)
1249{
1250 struct spi_master *master = spi->master;
1251 int ret;
1252 unsigned long flags;
1253
1254 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1255
1256 if (master->bus_lock_flag)
1257 ret = -EBUSY;
1258 else
1259 ret = __spi_async(spi, message);
1260
1261 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1262
1263 return ret;
1264}
1265EXPORT_SYMBOL_GPL(spi_async);
1266
1267/**
1268 * spi_async_locked - version of spi_async with exclusive bus usage
1269 * @spi: device with which data will be exchanged
1270 * @message: describes the data transfers, including completion callback
1271 * Context: any (irqs may be blocked, etc)
1272 *
1273 * This call may be used in_irq and other contexts which can't sleep,
1274 * as well as from task contexts which can sleep.
1275 *
1276 * The completion callback is invoked in a context which can't sleep.
1277 * Before that invocation, the value of message->status is undefined.
1278 * When the callback is issued, message->status holds either zero (to
1279 * indicate complete success) or a negative error code. After that
1280 * callback returns, the driver which issued the transfer request may
1281 * deallocate the associated memory; it's no longer in use by any SPI
1282 * core or controller driver code.
1283 *
1284 * Note that although all messages to a spi_device are handled in
1285 * FIFO order, messages may go to different devices in other orders.
1286 * Some device might be higher priority, or have various "hard" access
1287 * time requirements, for example.
1288 *
1289 * On detection of any fault during the transfer, processing of
1290 * the entire message is aborted, and the device is deselected.
1291 * Until returning from the associated message completion callback,
1292 * no other spi_message queued to that device will be processed.
1293 * (This rule applies equally to all the synchronous transfer calls,
1294 * which are wrappers around this core asynchronous primitive.)
1295 */
1296int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1297{
1298 struct spi_master *master = spi->master;
1299 int ret;
1300 unsigned long flags;
1301
1302 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1303
1304 ret = __spi_async(spi, message);
1305
1306 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1307
1308 return ret;
1309
1310}
1311EXPORT_SYMBOL_GPL(spi_async_locked);
1312
1313
1314/*-------------------------------------------------------------------------*/
1315
1316/* Utility methods for SPI master protocol drivers, layered on
1317 * top of the core. Some other utility methods are defined as
1318 * inline functions.
1319 */
1320
1321static void spi_complete(void *arg)
1322{
1323 complete(arg);
1324}
1325
1326static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1327 int bus_locked)
1328{
1329 DECLARE_COMPLETION_ONSTACK(done);
1330 int status;
1331 struct spi_master *master = spi->master;
1332
1333 message->complete = spi_complete;
1334 message->context = &done;
1335
1336 if (!bus_locked)
1337 mutex_lock(&master->bus_lock_mutex);
1338
1339 status = spi_async_locked(spi, message);
1340
1341 if (!bus_locked)
1342 mutex_unlock(&master->bus_lock_mutex);
1343
1344 if (status == 0) {
1345 wait_for_completion(&done);
1346 status = message->status;
1347 }
1348 message->context = NULL;
1349 return status;
1350}
1351
1352/**
1353 * spi_sync - blocking/synchronous SPI data transfers
1354 * @spi: device with which data will be exchanged
1355 * @message: describes the data transfers
1356 * Context: can sleep
1357 *
1358 * This call may only be used from a context that may sleep. The sleep
1359 * is non-interruptible, and has no timeout. Low-overhead controller
1360 * drivers may DMA directly into and out of the message buffers.
1361 *
1362 * Note that the SPI device's chip select is active during the message,
1363 * and then is normally disabled between messages. Drivers for some
1364 * frequently-used devices may want to minimize costs of selecting a chip,
1365 * by leaving it selected in anticipation that the next message will go
1366 * to the same chip. (That may increase power usage.)
1367 *
1368 * Also, the caller is guaranteeing that the memory associated with the
1369 * message will not be freed before this call returns.
1370 *
1371 * It returns zero on success, else a negative error code.
1372 */
1373int spi_sync(struct spi_device *spi, struct spi_message *message)
1374{
1375 return __spi_sync(spi, message, 0);
1376}
1377EXPORT_SYMBOL_GPL(spi_sync);
1378
1379/**
1380 * spi_sync_locked - version of spi_sync with exclusive bus usage
1381 * @spi: device with which data will be exchanged
1382 * @message: describes the data transfers
1383 * Context: can sleep
1384 *
1385 * This call may only be used from a context that may sleep. The sleep
1386 * is non-interruptible, and has no timeout. Low-overhead controller
1387 * drivers may DMA directly into and out of the message buffers.
1388 *
1389 * This call should be used by drivers that require exclusive access to the
1390 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1391 * be released by a spi_bus_unlock call when the exclusive access is over.
1392 *
1393 * It returns zero on success, else a negative error code.
1394 */
1395int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1396{
1397 return __spi_sync(spi, message, 1);
1398}
1399EXPORT_SYMBOL_GPL(spi_sync_locked);
1400
1401/**
1402 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1403 * @master: SPI bus master that should be locked for exclusive bus access
1404 * Context: can sleep
1405 *
1406 * This call may only be used from a context that may sleep. The sleep
1407 * is non-interruptible, and has no timeout.
1408 *
1409 * This call should be used by drivers that require exclusive access to the
1410 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1411 * exclusive access is over. Data transfer must be done by spi_sync_locked
1412 * and spi_async_locked calls when the SPI bus lock is held.
1413 *
1414 * It returns zero on success, else a negative error code.
1415 */
1416int spi_bus_lock(struct spi_master *master)
1417{
1418 unsigned long flags;
1419
1420 mutex_lock(&master->bus_lock_mutex);
1421
1422 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1423 master->bus_lock_flag = 1;
1424 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1425
1426 /* mutex remains locked until spi_bus_unlock is called */
1427
1428 return 0;
1429}
1430EXPORT_SYMBOL_GPL(spi_bus_lock);
1431
1432/**
1433 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1434 * @master: SPI bus master that was locked for exclusive bus access
1435 * Context: can sleep
1436 *
1437 * This call may only be used from a context that may sleep. The sleep
1438 * is non-interruptible, and has no timeout.
1439 *
1440 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1441 * call.
1442 *
1443 * It returns zero on success, else a negative error code.
1444 */
1445int spi_bus_unlock(struct spi_master *master)
1446{
1447 master->bus_lock_flag = 0;
1448
1449 mutex_unlock(&master->bus_lock_mutex);
1450
1451 return 0;
1452}
1453EXPORT_SYMBOL_GPL(spi_bus_unlock);
1454
1455/* portable code must never pass more than 32 bytes */
1456#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1457
1458static u8 *buf;
1459
1460/**
1461 * spi_write_then_read - SPI synchronous write followed by read
1462 * @spi: device with which data will be exchanged
1463 * @txbuf: data to be written (need not be dma-safe)
1464 * @n_tx: size of txbuf, in bytes
1465 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1466 * @n_rx: size of rxbuf, in bytes
1467 * Context: can sleep
1468 *
1469 * This performs a half duplex MicroWire style transaction with the
1470 * device, sending txbuf and then reading rxbuf. The return value
1471 * is zero for success, else a negative errno status code.
1472 * This call may only be used from a context that may sleep.
1473 *
1474 * Parameters to this routine are always copied using a small buffer;
1475 * portable code should never use this for more than 32 bytes.
1476 * Performance-sensitive or bulk transfer code should instead use
1477 * spi_{async,sync}() calls with dma-safe buffers.
1478 */
1479int spi_write_then_read(struct spi_device *spi,
1480 const void *txbuf, unsigned n_tx,
1481 void *rxbuf, unsigned n_rx)
1482{
1483 static DEFINE_MUTEX(lock);
1484
1485 int status;
1486 struct spi_message message;
1487 struct spi_transfer x[2];
1488 u8 *local_buf;
1489
1490 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1491 * (as a pure convenience thing), but we can keep heap costs
1492 * out of the hot path ...
1493 */
1494 if ((n_tx + n_rx) > SPI_BUFSIZ)
1495 return -EINVAL;
1496
1497 spi_message_init(&message);
1498 memset(x, 0, sizeof x);
1499 if (n_tx) {
1500 x[0].len = n_tx;
1501 spi_message_add_tail(&x[0], &message);
1502 }
1503 if (n_rx) {
1504 x[1].len = n_rx;
1505 spi_message_add_tail(&x[1], &message);
1506 }
1507
1508 /* ... unless someone else is using the pre-allocated buffer */
1509 if (!mutex_trylock(&lock)) {
1510 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1511 if (!local_buf)
1512 return -ENOMEM;
1513 } else
1514 local_buf = buf;
1515
1516 memcpy(local_buf, txbuf, n_tx);
1517 x[0].tx_buf = local_buf;
1518 x[1].rx_buf = local_buf + n_tx;
1519
1520 /* do the i/o */
1521 status = spi_sync(spi, &message);
1522 if (status == 0)
1523 memcpy(rxbuf, x[1].rx_buf, n_rx);
1524
1525 if (x[0].tx_buf == buf)
1526 mutex_unlock(&lock);
1527 else
1528 kfree(local_buf);
1529
1530 return status;
1531}
1532EXPORT_SYMBOL_GPL(spi_write_then_read);
1533
1534/*-------------------------------------------------------------------------*/
1535
1536static int __init spi_init(void)
1537{
1538 int status;
1539
1540 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1541 if (!buf) {
1542 status = -ENOMEM;
1543 goto err0;
1544 }
1545
1546 status = bus_register(&spi_bus_type);
1547 if (status < 0)
1548 goto err1;
1549
1550 status = class_register(&spi_master_class);
1551 if (status < 0)
1552 goto err2;
1553 return 0;
1554
1555err2:
1556 bus_unregister(&spi_bus_type);
1557err1:
1558 kfree(buf);
1559 buf = NULL;
1560err0:
1561 return status;
1562}
1563
1564/* board_info is normally registered in arch_initcall(),
1565 * but even essential drivers wait till later
1566 *
1567 * REVISIT only boardinfo really needs static linking. the rest (device and
1568 * driver registration) _could_ be dynamically linked (modular) ... costs
1569 * include needing to have boardinfo data structures be much more public.
1570 */
1571postcore_initcall(spi_init);
1572
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
18#include <linux/kernel.h>
19#include <linux/device.h>
20#include <linux/init.h>
21#include <linux/cache.h>
22#include <linux/dma-mapping.h>
23#include <linux/dmaengine.h>
24#include <linux/mutex.h>
25#include <linux/of_device.h>
26#include <linux/of_irq.h>
27#include <linux/clk/clk-conf.h>
28#include <linux/slab.h>
29#include <linux/mod_devicetable.h>
30#include <linux/spi/spi.h>
31#include <linux/of_gpio.h>
32#include <linux/pm_runtime.h>
33#include <linux/pm_domain.h>
34#include <linux/export.h>
35#include <linux/sched/rt.h>
36#include <linux/delay.h>
37#include <linux/kthread.h>
38#include <linux/ioport.h>
39#include <linux/acpi.h>
40#include <linux/highmem.h>
41
42#define CREATE_TRACE_POINTS
43#include <trace/events/spi.h>
44
45static void spidev_release(struct device *dev)
46{
47 struct spi_device *spi = to_spi_device(dev);
48
49 /* spi masters may cleanup for released devices */
50 if (spi->master->cleanup)
51 spi->master->cleanup(spi);
52
53 spi_master_put(spi->master);
54 kfree(spi);
55}
56
57static ssize_t
58modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59{
60 const struct spi_device *spi = to_spi_device(dev);
61 int len;
62
63 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
64 if (len != -ENODEV)
65 return len;
66
67 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68}
69static DEVICE_ATTR_RO(modalias);
70
71#define SPI_STATISTICS_ATTRS(field, file) \
72static ssize_t spi_master_##field##_show(struct device *dev, \
73 struct device_attribute *attr, \
74 char *buf) \
75{ \
76 struct spi_master *master = container_of(dev, \
77 struct spi_master, dev); \
78 return spi_statistics_##field##_show(&master->statistics, buf); \
79} \
80static struct device_attribute dev_attr_spi_master_##field = { \
81 .attr = { .name = file, .mode = S_IRUGO }, \
82 .show = spi_master_##field##_show, \
83}; \
84static ssize_t spi_device_##field##_show(struct device *dev, \
85 struct device_attribute *attr, \
86 char *buf) \
87{ \
88 struct spi_device *spi = to_spi_device(dev); \
89 return spi_statistics_##field##_show(&spi->statistics, buf); \
90} \
91static struct device_attribute dev_attr_spi_device_##field = { \
92 .attr = { .name = file, .mode = S_IRUGO }, \
93 .show = spi_device_##field##_show, \
94}
95
96#define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
97static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
98 char *buf) \
99{ \
100 unsigned long flags; \
101 ssize_t len; \
102 spin_lock_irqsave(&stat->lock, flags); \
103 len = sprintf(buf, format_string, stat->field); \
104 spin_unlock_irqrestore(&stat->lock, flags); \
105 return len; \
106} \
107SPI_STATISTICS_ATTRS(name, file)
108
109#define SPI_STATISTICS_SHOW(field, format_string) \
110 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
111 field, format_string)
112
113SPI_STATISTICS_SHOW(messages, "%lu");
114SPI_STATISTICS_SHOW(transfers, "%lu");
115SPI_STATISTICS_SHOW(errors, "%lu");
116SPI_STATISTICS_SHOW(timedout, "%lu");
117
118SPI_STATISTICS_SHOW(spi_sync, "%lu");
119SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120SPI_STATISTICS_SHOW(spi_async, "%lu");
121
122SPI_STATISTICS_SHOW(bytes, "%llu");
123SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125
126#define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
127 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
128 "transfer_bytes_histo_" number, \
129 transfer_bytes_histo[index], "%lu")
130SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
131SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
132SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
133SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
134SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
135SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
136SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
137SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
138SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
139SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
140SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
141SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
142SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
143SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
144SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
145SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
146SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147
148SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
149
150static struct attribute *spi_dev_attrs[] = {
151 &dev_attr_modalias.attr,
152 NULL,
153};
154
155static const struct attribute_group spi_dev_group = {
156 .attrs = spi_dev_attrs,
157};
158
159static struct attribute *spi_device_statistics_attrs[] = {
160 &dev_attr_spi_device_messages.attr,
161 &dev_attr_spi_device_transfers.attr,
162 &dev_attr_spi_device_errors.attr,
163 &dev_attr_spi_device_timedout.attr,
164 &dev_attr_spi_device_spi_sync.attr,
165 &dev_attr_spi_device_spi_sync_immediate.attr,
166 &dev_attr_spi_device_spi_async.attr,
167 &dev_attr_spi_device_bytes.attr,
168 &dev_attr_spi_device_bytes_rx.attr,
169 &dev_attr_spi_device_bytes_tx.attr,
170 &dev_attr_spi_device_transfer_bytes_histo0.attr,
171 &dev_attr_spi_device_transfer_bytes_histo1.attr,
172 &dev_attr_spi_device_transfer_bytes_histo2.attr,
173 &dev_attr_spi_device_transfer_bytes_histo3.attr,
174 &dev_attr_spi_device_transfer_bytes_histo4.attr,
175 &dev_attr_spi_device_transfer_bytes_histo5.attr,
176 &dev_attr_spi_device_transfer_bytes_histo6.attr,
177 &dev_attr_spi_device_transfer_bytes_histo7.attr,
178 &dev_attr_spi_device_transfer_bytes_histo8.attr,
179 &dev_attr_spi_device_transfer_bytes_histo9.attr,
180 &dev_attr_spi_device_transfer_bytes_histo10.attr,
181 &dev_attr_spi_device_transfer_bytes_histo11.attr,
182 &dev_attr_spi_device_transfer_bytes_histo12.attr,
183 &dev_attr_spi_device_transfer_bytes_histo13.attr,
184 &dev_attr_spi_device_transfer_bytes_histo14.attr,
185 &dev_attr_spi_device_transfer_bytes_histo15.attr,
186 &dev_attr_spi_device_transfer_bytes_histo16.attr,
187 &dev_attr_spi_device_transfers_split_maxsize.attr,
188 NULL,
189};
190
191static const struct attribute_group spi_device_statistics_group = {
192 .name = "statistics",
193 .attrs = spi_device_statistics_attrs,
194};
195
196static const struct attribute_group *spi_dev_groups[] = {
197 &spi_dev_group,
198 &spi_device_statistics_group,
199 NULL,
200};
201
202static struct attribute *spi_master_statistics_attrs[] = {
203 &dev_attr_spi_master_messages.attr,
204 &dev_attr_spi_master_transfers.attr,
205 &dev_attr_spi_master_errors.attr,
206 &dev_attr_spi_master_timedout.attr,
207 &dev_attr_spi_master_spi_sync.attr,
208 &dev_attr_spi_master_spi_sync_immediate.attr,
209 &dev_attr_spi_master_spi_async.attr,
210 &dev_attr_spi_master_bytes.attr,
211 &dev_attr_spi_master_bytes_rx.attr,
212 &dev_attr_spi_master_bytes_tx.attr,
213 &dev_attr_spi_master_transfer_bytes_histo0.attr,
214 &dev_attr_spi_master_transfer_bytes_histo1.attr,
215 &dev_attr_spi_master_transfer_bytes_histo2.attr,
216 &dev_attr_spi_master_transfer_bytes_histo3.attr,
217 &dev_attr_spi_master_transfer_bytes_histo4.attr,
218 &dev_attr_spi_master_transfer_bytes_histo5.attr,
219 &dev_attr_spi_master_transfer_bytes_histo6.attr,
220 &dev_attr_spi_master_transfer_bytes_histo7.attr,
221 &dev_attr_spi_master_transfer_bytes_histo8.attr,
222 &dev_attr_spi_master_transfer_bytes_histo9.attr,
223 &dev_attr_spi_master_transfer_bytes_histo10.attr,
224 &dev_attr_spi_master_transfer_bytes_histo11.attr,
225 &dev_attr_spi_master_transfer_bytes_histo12.attr,
226 &dev_attr_spi_master_transfer_bytes_histo13.attr,
227 &dev_attr_spi_master_transfer_bytes_histo14.attr,
228 &dev_attr_spi_master_transfer_bytes_histo15.attr,
229 &dev_attr_spi_master_transfer_bytes_histo16.attr,
230 &dev_attr_spi_master_transfers_split_maxsize.attr,
231 NULL,
232};
233
234static const struct attribute_group spi_master_statistics_group = {
235 .name = "statistics",
236 .attrs = spi_master_statistics_attrs,
237};
238
239static const struct attribute_group *spi_master_groups[] = {
240 &spi_master_statistics_group,
241 NULL,
242};
243
244void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
245 struct spi_transfer *xfer,
246 struct spi_master *master)
247{
248 unsigned long flags;
249 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
250
251 if (l2len < 0)
252 l2len = 0;
253
254 spin_lock_irqsave(&stats->lock, flags);
255
256 stats->transfers++;
257 stats->transfer_bytes_histo[l2len]++;
258
259 stats->bytes += xfer->len;
260 if ((xfer->tx_buf) &&
261 (xfer->tx_buf != master->dummy_tx))
262 stats->bytes_tx += xfer->len;
263 if ((xfer->rx_buf) &&
264 (xfer->rx_buf != master->dummy_rx))
265 stats->bytes_rx += xfer->len;
266
267 spin_unlock_irqrestore(&stats->lock, flags);
268}
269EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
270
271/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
272 * and the sysfs version makes coldplug work too.
273 */
274
275static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
276 const struct spi_device *sdev)
277{
278 while (id->name[0]) {
279 if (!strcmp(sdev->modalias, id->name))
280 return id;
281 id++;
282 }
283 return NULL;
284}
285
286const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
287{
288 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
289
290 return spi_match_id(sdrv->id_table, sdev);
291}
292EXPORT_SYMBOL_GPL(spi_get_device_id);
293
294static int spi_match_device(struct device *dev, struct device_driver *drv)
295{
296 const struct spi_device *spi = to_spi_device(dev);
297 const struct spi_driver *sdrv = to_spi_driver(drv);
298
299 /* Attempt an OF style match */
300 if (of_driver_match_device(dev, drv))
301 return 1;
302
303 /* Then try ACPI */
304 if (acpi_driver_match_device(dev, drv))
305 return 1;
306
307 if (sdrv->id_table)
308 return !!spi_match_id(sdrv->id_table, spi);
309
310 return strcmp(spi->modalias, drv->name) == 0;
311}
312
313static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
314{
315 const struct spi_device *spi = to_spi_device(dev);
316 int rc;
317
318 rc = acpi_device_uevent_modalias(dev, env);
319 if (rc != -ENODEV)
320 return rc;
321
322 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
323 return 0;
324}
325
326struct bus_type spi_bus_type = {
327 .name = "spi",
328 .dev_groups = spi_dev_groups,
329 .match = spi_match_device,
330 .uevent = spi_uevent,
331};
332EXPORT_SYMBOL_GPL(spi_bus_type);
333
334
335static int spi_drv_probe(struct device *dev)
336{
337 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
338 struct spi_device *spi = to_spi_device(dev);
339 int ret;
340
341 ret = of_clk_set_defaults(dev->of_node, false);
342 if (ret)
343 return ret;
344
345 if (dev->of_node) {
346 spi->irq = of_irq_get(dev->of_node, 0);
347 if (spi->irq == -EPROBE_DEFER)
348 return -EPROBE_DEFER;
349 if (spi->irq < 0)
350 spi->irq = 0;
351 }
352
353 ret = dev_pm_domain_attach(dev, true);
354 if (ret != -EPROBE_DEFER) {
355 ret = sdrv->probe(spi);
356 if (ret)
357 dev_pm_domain_detach(dev, true);
358 }
359
360 return ret;
361}
362
363static int spi_drv_remove(struct device *dev)
364{
365 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
366 int ret;
367
368 ret = sdrv->remove(to_spi_device(dev));
369 dev_pm_domain_detach(dev, true);
370
371 return ret;
372}
373
374static void spi_drv_shutdown(struct device *dev)
375{
376 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
377
378 sdrv->shutdown(to_spi_device(dev));
379}
380
381/**
382 * __spi_register_driver - register a SPI driver
383 * @owner: owner module of the driver to register
384 * @sdrv: the driver to register
385 * Context: can sleep
386 *
387 * Return: zero on success, else a negative error code.
388 */
389int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
390{
391 sdrv->driver.owner = owner;
392 sdrv->driver.bus = &spi_bus_type;
393 if (sdrv->probe)
394 sdrv->driver.probe = spi_drv_probe;
395 if (sdrv->remove)
396 sdrv->driver.remove = spi_drv_remove;
397 if (sdrv->shutdown)
398 sdrv->driver.shutdown = spi_drv_shutdown;
399 return driver_register(&sdrv->driver);
400}
401EXPORT_SYMBOL_GPL(__spi_register_driver);
402
403/*-------------------------------------------------------------------------*/
404
405/* SPI devices should normally not be created by SPI device drivers; that
406 * would make them board-specific. Similarly with SPI master drivers.
407 * Device registration normally goes into like arch/.../mach.../board-YYY.c
408 * with other readonly (flashable) information about mainboard devices.
409 */
410
411struct boardinfo {
412 struct list_head list;
413 struct spi_board_info board_info;
414};
415
416static LIST_HEAD(board_list);
417static LIST_HEAD(spi_master_list);
418
419/*
420 * Used to protect add/del opertion for board_info list and
421 * spi_master list, and their matching process
422 */
423static DEFINE_MUTEX(board_lock);
424
425/**
426 * spi_alloc_device - Allocate a new SPI device
427 * @master: Controller to which device is connected
428 * Context: can sleep
429 *
430 * Allows a driver to allocate and initialize a spi_device without
431 * registering it immediately. This allows a driver to directly
432 * fill the spi_device with device parameters before calling
433 * spi_add_device() on it.
434 *
435 * Caller is responsible to call spi_add_device() on the returned
436 * spi_device structure to add it to the SPI master. If the caller
437 * needs to discard the spi_device without adding it, then it should
438 * call spi_dev_put() on it.
439 *
440 * Return: a pointer to the new device, or NULL.
441 */
442struct spi_device *spi_alloc_device(struct spi_master *master)
443{
444 struct spi_device *spi;
445
446 if (!spi_master_get(master))
447 return NULL;
448
449 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
450 if (!spi) {
451 spi_master_put(master);
452 return NULL;
453 }
454
455 spi->master = master;
456 spi->dev.parent = &master->dev;
457 spi->dev.bus = &spi_bus_type;
458 spi->dev.release = spidev_release;
459 spi->cs_gpio = -ENOENT;
460
461 spin_lock_init(&spi->statistics.lock);
462
463 device_initialize(&spi->dev);
464 return spi;
465}
466EXPORT_SYMBOL_GPL(spi_alloc_device);
467
468static void spi_dev_set_name(struct spi_device *spi)
469{
470 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
471
472 if (adev) {
473 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
474 return;
475 }
476
477 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
478 spi->chip_select);
479}
480
481static int spi_dev_check(struct device *dev, void *data)
482{
483 struct spi_device *spi = to_spi_device(dev);
484 struct spi_device *new_spi = data;
485
486 if (spi->master == new_spi->master &&
487 spi->chip_select == new_spi->chip_select)
488 return -EBUSY;
489 return 0;
490}
491
492/**
493 * spi_add_device - Add spi_device allocated with spi_alloc_device
494 * @spi: spi_device to register
495 *
496 * Companion function to spi_alloc_device. Devices allocated with
497 * spi_alloc_device can be added onto the spi bus with this function.
498 *
499 * Return: 0 on success; negative errno on failure
500 */
501int spi_add_device(struct spi_device *spi)
502{
503 static DEFINE_MUTEX(spi_add_lock);
504 struct spi_master *master = spi->master;
505 struct device *dev = master->dev.parent;
506 int status;
507
508 /* Chipselects are numbered 0..max; validate. */
509 if (spi->chip_select >= master->num_chipselect) {
510 dev_err(dev, "cs%d >= max %d\n",
511 spi->chip_select,
512 master->num_chipselect);
513 return -EINVAL;
514 }
515
516 /* Set the bus ID string */
517 spi_dev_set_name(spi);
518
519 /* We need to make sure there's no other device with this
520 * chipselect **BEFORE** we call setup(), else we'll trash
521 * its configuration. Lock against concurrent add() calls.
522 */
523 mutex_lock(&spi_add_lock);
524
525 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
526 if (status) {
527 dev_err(dev, "chipselect %d already in use\n",
528 spi->chip_select);
529 goto done;
530 }
531
532 if (master->cs_gpios)
533 spi->cs_gpio = master->cs_gpios[spi->chip_select];
534
535 /* Drivers may modify this initial i/o setup, but will
536 * normally rely on the device being setup. Devices
537 * using SPI_CS_HIGH can't coexist well otherwise...
538 */
539 status = spi_setup(spi);
540 if (status < 0) {
541 dev_err(dev, "can't setup %s, status %d\n",
542 dev_name(&spi->dev), status);
543 goto done;
544 }
545
546 /* Device may be bound to an active driver when this returns */
547 status = device_add(&spi->dev);
548 if (status < 0)
549 dev_err(dev, "can't add %s, status %d\n",
550 dev_name(&spi->dev), status);
551 else
552 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
553
554done:
555 mutex_unlock(&spi_add_lock);
556 return status;
557}
558EXPORT_SYMBOL_GPL(spi_add_device);
559
560/**
561 * spi_new_device - instantiate one new SPI device
562 * @master: Controller to which device is connected
563 * @chip: Describes the SPI device
564 * Context: can sleep
565 *
566 * On typical mainboards, this is purely internal; and it's not needed
567 * after board init creates the hard-wired devices. Some development
568 * platforms may not be able to use spi_register_board_info though, and
569 * this is exported so that for example a USB or parport based adapter
570 * driver could add devices (which it would learn about out-of-band).
571 *
572 * Return: the new device, or NULL.
573 */
574struct spi_device *spi_new_device(struct spi_master *master,
575 struct spi_board_info *chip)
576{
577 struct spi_device *proxy;
578 int status;
579
580 /* NOTE: caller did any chip->bus_num checks necessary.
581 *
582 * Also, unless we change the return value convention to use
583 * error-or-pointer (not NULL-or-pointer), troubleshootability
584 * suggests syslogged diagnostics are best here (ugh).
585 */
586
587 proxy = spi_alloc_device(master);
588 if (!proxy)
589 return NULL;
590
591 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
592
593 proxy->chip_select = chip->chip_select;
594 proxy->max_speed_hz = chip->max_speed_hz;
595 proxy->mode = chip->mode;
596 proxy->irq = chip->irq;
597 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
598 proxy->dev.platform_data = (void *) chip->platform_data;
599 proxy->controller_data = chip->controller_data;
600 proxy->controller_state = NULL;
601
602 status = spi_add_device(proxy);
603 if (status < 0) {
604 spi_dev_put(proxy);
605 return NULL;
606 }
607
608 return proxy;
609}
610EXPORT_SYMBOL_GPL(spi_new_device);
611
612/**
613 * spi_unregister_device - unregister a single SPI device
614 * @spi: spi_device to unregister
615 *
616 * Start making the passed SPI device vanish. Normally this would be handled
617 * by spi_unregister_master().
618 */
619void spi_unregister_device(struct spi_device *spi)
620{
621 if (!spi)
622 return;
623
624 if (spi->dev.of_node)
625 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
626 if (ACPI_COMPANION(&spi->dev))
627 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
628 device_unregister(&spi->dev);
629}
630EXPORT_SYMBOL_GPL(spi_unregister_device);
631
632static void spi_match_master_to_boardinfo(struct spi_master *master,
633 struct spi_board_info *bi)
634{
635 struct spi_device *dev;
636
637 if (master->bus_num != bi->bus_num)
638 return;
639
640 dev = spi_new_device(master, bi);
641 if (!dev)
642 dev_err(master->dev.parent, "can't create new device for %s\n",
643 bi->modalias);
644}
645
646/**
647 * spi_register_board_info - register SPI devices for a given board
648 * @info: array of chip descriptors
649 * @n: how many descriptors are provided
650 * Context: can sleep
651 *
652 * Board-specific early init code calls this (probably during arch_initcall)
653 * with segments of the SPI device table. Any device nodes are created later,
654 * after the relevant parent SPI controller (bus_num) is defined. We keep
655 * this table of devices forever, so that reloading a controller driver will
656 * not make Linux forget about these hard-wired devices.
657 *
658 * Other code can also call this, e.g. a particular add-on board might provide
659 * SPI devices through its expansion connector, so code initializing that board
660 * would naturally declare its SPI devices.
661 *
662 * The board info passed can safely be __initdata ... but be careful of
663 * any embedded pointers (platform_data, etc), they're copied as-is.
664 *
665 * Return: zero on success, else a negative error code.
666 */
667int spi_register_board_info(struct spi_board_info const *info, unsigned n)
668{
669 struct boardinfo *bi;
670 int i;
671
672 if (!n)
673 return -EINVAL;
674
675 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
676 if (!bi)
677 return -ENOMEM;
678
679 for (i = 0; i < n; i++, bi++, info++) {
680 struct spi_master *master;
681
682 memcpy(&bi->board_info, info, sizeof(*info));
683 mutex_lock(&board_lock);
684 list_add_tail(&bi->list, &board_list);
685 list_for_each_entry(master, &spi_master_list, list)
686 spi_match_master_to_boardinfo(master, &bi->board_info);
687 mutex_unlock(&board_lock);
688 }
689
690 return 0;
691}
692
693/*-------------------------------------------------------------------------*/
694
695static void spi_set_cs(struct spi_device *spi, bool enable)
696{
697 if (spi->mode & SPI_CS_HIGH)
698 enable = !enable;
699
700 if (gpio_is_valid(spi->cs_gpio)) {
701 gpio_set_value(spi->cs_gpio, !enable);
702 /* Some SPI masters need both GPIO CS & slave_select */
703 if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
704 spi->master->set_cs)
705 spi->master->set_cs(spi, !enable);
706 } else if (spi->master->set_cs) {
707 spi->master->set_cs(spi, !enable);
708 }
709}
710
711#ifdef CONFIG_HAS_DMA
712static int spi_map_buf(struct spi_master *master, struct device *dev,
713 struct sg_table *sgt, void *buf, size_t len,
714 enum dma_data_direction dir)
715{
716 const bool vmalloced_buf = is_vmalloc_addr(buf);
717 unsigned int max_seg_size = dma_get_max_seg_size(dev);
718#ifdef CONFIG_HIGHMEM
719 const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
720 (unsigned long)buf < (PKMAP_BASE +
721 (LAST_PKMAP * PAGE_SIZE)));
722#else
723 const bool kmap_buf = false;
724#endif
725 int desc_len;
726 int sgs;
727 struct page *vm_page;
728 struct scatterlist *sg;
729 void *sg_buf;
730 size_t min;
731 int i, ret;
732
733 if (vmalloced_buf || kmap_buf) {
734 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
735 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
736 } else if (virt_addr_valid(buf)) {
737 desc_len = min_t(int, max_seg_size, master->max_dma_len);
738 sgs = DIV_ROUND_UP(len, desc_len);
739 } else {
740 return -EINVAL;
741 }
742
743 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
744 if (ret != 0)
745 return ret;
746
747 sg = &sgt->sgl[0];
748 for (i = 0; i < sgs; i++) {
749
750 if (vmalloced_buf || kmap_buf) {
751 min = min_t(size_t,
752 len, desc_len - offset_in_page(buf));
753 if (vmalloced_buf)
754 vm_page = vmalloc_to_page(buf);
755 else
756 vm_page = kmap_to_page(buf);
757 if (!vm_page) {
758 sg_free_table(sgt);
759 return -ENOMEM;
760 }
761 sg_set_page(sg, vm_page,
762 min, offset_in_page(buf));
763 } else {
764 min = min_t(size_t, len, desc_len);
765 sg_buf = buf;
766 sg_set_buf(sg, sg_buf, min);
767 }
768
769 buf += min;
770 len -= min;
771 sg = sg_next(sg);
772 }
773
774 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
775 if (!ret)
776 ret = -ENOMEM;
777 if (ret < 0) {
778 sg_free_table(sgt);
779 return ret;
780 }
781
782 sgt->nents = ret;
783
784 return 0;
785}
786
787static void spi_unmap_buf(struct spi_master *master, struct device *dev,
788 struct sg_table *sgt, enum dma_data_direction dir)
789{
790 if (sgt->orig_nents) {
791 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
792 sg_free_table(sgt);
793 }
794}
795
796static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
797{
798 struct device *tx_dev, *rx_dev;
799 struct spi_transfer *xfer;
800 int ret;
801
802 if (!master->can_dma)
803 return 0;
804
805 if (master->dma_tx)
806 tx_dev = master->dma_tx->device->dev;
807 else
808 tx_dev = &master->dev;
809
810 if (master->dma_rx)
811 rx_dev = master->dma_rx->device->dev;
812 else
813 rx_dev = &master->dev;
814
815 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
816 if (!master->can_dma(master, msg->spi, xfer))
817 continue;
818
819 if (xfer->tx_buf != NULL) {
820 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
821 (void *)xfer->tx_buf, xfer->len,
822 DMA_TO_DEVICE);
823 if (ret != 0)
824 return ret;
825 }
826
827 if (xfer->rx_buf != NULL) {
828 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
829 xfer->rx_buf, xfer->len,
830 DMA_FROM_DEVICE);
831 if (ret != 0) {
832 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
833 DMA_TO_DEVICE);
834 return ret;
835 }
836 }
837 }
838
839 master->cur_msg_mapped = true;
840
841 return 0;
842}
843
844static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
845{
846 struct spi_transfer *xfer;
847 struct device *tx_dev, *rx_dev;
848
849 if (!master->cur_msg_mapped || !master->can_dma)
850 return 0;
851
852 if (master->dma_tx)
853 tx_dev = master->dma_tx->device->dev;
854 else
855 tx_dev = &master->dev;
856
857 if (master->dma_rx)
858 rx_dev = master->dma_rx->device->dev;
859 else
860 rx_dev = &master->dev;
861
862 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
863 if (!master->can_dma(master, msg->spi, xfer))
864 continue;
865
866 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
867 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
868 }
869
870 return 0;
871}
872#else /* !CONFIG_HAS_DMA */
873static inline int spi_map_buf(struct spi_master *master,
874 struct device *dev, struct sg_table *sgt,
875 void *buf, size_t len,
876 enum dma_data_direction dir)
877{
878 return -EINVAL;
879}
880
881static inline void spi_unmap_buf(struct spi_master *master,
882 struct device *dev, struct sg_table *sgt,
883 enum dma_data_direction dir)
884{
885}
886
887static inline int __spi_map_msg(struct spi_master *master,
888 struct spi_message *msg)
889{
890 return 0;
891}
892
893static inline int __spi_unmap_msg(struct spi_master *master,
894 struct spi_message *msg)
895{
896 return 0;
897}
898#endif /* !CONFIG_HAS_DMA */
899
900static inline int spi_unmap_msg(struct spi_master *master,
901 struct spi_message *msg)
902{
903 struct spi_transfer *xfer;
904
905 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
906 /*
907 * Restore the original value of tx_buf or rx_buf if they are
908 * NULL.
909 */
910 if (xfer->tx_buf == master->dummy_tx)
911 xfer->tx_buf = NULL;
912 if (xfer->rx_buf == master->dummy_rx)
913 xfer->rx_buf = NULL;
914 }
915
916 return __spi_unmap_msg(master, msg);
917}
918
919static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
920{
921 struct spi_transfer *xfer;
922 void *tmp;
923 unsigned int max_tx, max_rx;
924
925 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
926 max_tx = 0;
927 max_rx = 0;
928
929 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
930 if ((master->flags & SPI_MASTER_MUST_TX) &&
931 !xfer->tx_buf)
932 max_tx = max(xfer->len, max_tx);
933 if ((master->flags & SPI_MASTER_MUST_RX) &&
934 !xfer->rx_buf)
935 max_rx = max(xfer->len, max_rx);
936 }
937
938 if (max_tx) {
939 tmp = krealloc(master->dummy_tx, max_tx,
940 GFP_KERNEL | GFP_DMA);
941 if (!tmp)
942 return -ENOMEM;
943 master->dummy_tx = tmp;
944 memset(tmp, 0, max_tx);
945 }
946
947 if (max_rx) {
948 tmp = krealloc(master->dummy_rx, max_rx,
949 GFP_KERNEL | GFP_DMA);
950 if (!tmp)
951 return -ENOMEM;
952 master->dummy_rx = tmp;
953 }
954
955 if (max_tx || max_rx) {
956 list_for_each_entry(xfer, &msg->transfers,
957 transfer_list) {
958 if (!xfer->tx_buf)
959 xfer->tx_buf = master->dummy_tx;
960 if (!xfer->rx_buf)
961 xfer->rx_buf = master->dummy_rx;
962 }
963 }
964 }
965
966 return __spi_map_msg(master, msg);
967}
968
969/*
970 * spi_transfer_one_message - Default implementation of transfer_one_message()
971 *
972 * This is a standard implementation of transfer_one_message() for
973 * drivers which implement a transfer_one() operation. It provides
974 * standard handling of delays and chip select management.
975 */
976static int spi_transfer_one_message(struct spi_master *master,
977 struct spi_message *msg)
978{
979 struct spi_transfer *xfer;
980 bool keep_cs = false;
981 int ret = 0;
982 unsigned long long ms = 1;
983 struct spi_statistics *statm = &master->statistics;
984 struct spi_statistics *stats = &msg->spi->statistics;
985
986 spi_set_cs(msg->spi, true);
987
988 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
989 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
990
991 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
992 trace_spi_transfer_start(msg, xfer);
993
994 spi_statistics_add_transfer_stats(statm, xfer, master);
995 spi_statistics_add_transfer_stats(stats, xfer, master);
996
997 if (xfer->tx_buf || xfer->rx_buf) {
998 reinit_completion(&master->xfer_completion);
999
1000 ret = master->transfer_one(master, msg->spi, xfer);
1001 if (ret < 0) {
1002 SPI_STATISTICS_INCREMENT_FIELD(statm,
1003 errors);
1004 SPI_STATISTICS_INCREMENT_FIELD(stats,
1005 errors);
1006 dev_err(&msg->spi->dev,
1007 "SPI transfer failed: %d\n", ret);
1008 goto out;
1009 }
1010
1011 if (ret > 0) {
1012 ret = 0;
1013 ms = 8LL * 1000LL * xfer->len;
1014 do_div(ms, xfer->speed_hz);
1015 ms += ms + 100; /* some tolerance */
1016
1017 if (ms > UINT_MAX)
1018 ms = UINT_MAX;
1019
1020 ms = wait_for_completion_timeout(&master->xfer_completion,
1021 msecs_to_jiffies(ms));
1022 }
1023
1024 if (ms == 0) {
1025 SPI_STATISTICS_INCREMENT_FIELD(statm,
1026 timedout);
1027 SPI_STATISTICS_INCREMENT_FIELD(stats,
1028 timedout);
1029 dev_err(&msg->spi->dev,
1030 "SPI transfer timed out\n");
1031 msg->status = -ETIMEDOUT;
1032 }
1033 } else {
1034 if (xfer->len)
1035 dev_err(&msg->spi->dev,
1036 "Bufferless transfer has length %u\n",
1037 xfer->len);
1038 }
1039
1040 trace_spi_transfer_stop(msg, xfer);
1041
1042 if (msg->status != -EINPROGRESS)
1043 goto out;
1044
1045 if (xfer->delay_usecs) {
1046 u16 us = xfer->delay_usecs;
1047
1048 if (us <= 10)
1049 udelay(us);
1050 else
1051 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1052 }
1053
1054 if (xfer->cs_change) {
1055 if (list_is_last(&xfer->transfer_list,
1056 &msg->transfers)) {
1057 keep_cs = true;
1058 } else {
1059 spi_set_cs(msg->spi, false);
1060 udelay(10);
1061 spi_set_cs(msg->spi, true);
1062 }
1063 }
1064
1065 msg->actual_length += xfer->len;
1066 }
1067
1068out:
1069 if (ret != 0 || !keep_cs)
1070 spi_set_cs(msg->spi, false);
1071
1072 if (msg->status == -EINPROGRESS)
1073 msg->status = ret;
1074
1075 if (msg->status && master->handle_err)
1076 master->handle_err(master, msg);
1077
1078 spi_res_release(master, msg);
1079
1080 spi_finalize_current_message(master);
1081
1082 return ret;
1083}
1084
1085/**
1086 * spi_finalize_current_transfer - report completion of a transfer
1087 * @master: the master reporting completion
1088 *
1089 * Called by SPI drivers using the core transfer_one_message()
1090 * implementation to notify it that the current interrupt driven
1091 * transfer has finished and the next one may be scheduled.
1092 */
1093void spi_finalize_current_transfer(struct spi_master *master)
1094{
1095 complete(&master->xfer_completion);
1096}
1097EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1098
1099/**
1100 * __spi_pump_messages - function which processes spi message queue
1101 * @master: master to process queue for
1102 * @in_kthread: true if we are in the context of the message pump thread
1103 *
1104 * This function checks if there is any spi message in the queue that
1105 * needs processing and if so call out to the driver to initialize hardware
1106 * and transfer each message.
1107 *
1108 * Note that it is called both from the kthread itself and also from
1109 * inside spi_sync(); the queue extraction handling at the top of the
1110 * function should deal with this safely.
1111 */
1112static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1113{
1114 unsigned long flags;
1115 bool was_busy = false;
1116 int ret;
1117
1118 /* Lock queue */
1119 spin_lock_irqsave(&master->queue_lock, flags);
1120
1121 /* Make sure we are not already running a message */
1122 if (master->cur_msg) {
1123 spin_unlock_irqrestore(&master->queue_lock, flags);
1124 return;
1125 }
1126
1127 /* If another context is idling the device then defer */
1128 if (master->idling) {
1129 kthread_queue_work(&master->kworker, &master->pump_messages);
1130 spin_unlock_irqrestore(&master->queue_lock, flags);
1131 return;
1132 }
1133
1134 /* Check if the queue is idle */
1135 if (list_empty(&master->queue) || !master->running) {
1136 if (!master->busy) {
1137 spin_unlock_irqrestore(&master->queue_lock, flags);
1138 return;
1139 }
1140
1141 /* Only do teardown in the thread */
1142 if (!in_kthread) {
1143 kthread_queue_work(&master->kworker,
1144 &master->pump_messages);
1145 spin_unlock_irqrestore(&master->queue_lock, flags);
1146 return;
1147 }
1148
1149 master->busy = false;
1150 master->idling = true;
1151 spin_unlock_irqrestore(&master->queue_lock, flags);
1152
1153 kfree(master->dummy_rx);
1154 master->dummy_rx = NULL;
1155 kfree(master->dummy_tx);
1156 master->dummy_tx = NULL;
1157 if (master->unprepare_transfer_hardware &&
1158 master->unprepare_transfer_hardware(master))
1159 dev_err(&master->dev,
1160 "failed to unprepare transfer hardware\n");
1161 if (master->auto_runtime_pm) {
1162 pm_runtime_mark_last_busy(master->dev.parent);
1163 pm_runtime_put_autosuspend(master->dev.parent);
1164 }
1165 trace_spi_master_idle(master);
1166
1167 spin_lock_irqsave(&master->queue_lock, flags);
1168 master->idling = false;
1169 spin_unlock_irqrestore(&master->queue_lock, flags);
1170 return;
1171 }
1172
1173 /* Extract head of queue */
1174 master->cur_msg =
1175 list_first_entry(&master->queue, struct spi_message, queue);
1176
1177 list_del_init(&master->cur_msg->queue);
1178 if (master->busy)
1179 was_busy = true;
1180 else
1181 master->busy = true;
1182 spin_unlock_irqrestore(&master->queue_lock, flags);
1183
1184 mutex_lock(&master->io_mutex);
1185
1186 if (!was_busy && master->auto_runtime_pm) {
1187 ret = pm_runtime_get_sync(master->dev.parent);
1188 if (ret < 0) {
1189 dev_err(&master->dev, "Failed to power device: %d\n",
1190 ret);
1191 mutex_unlock(&master->io_mutex);
1192 return;
1193 }
1194 }
1195
1196 if (!was_busy)
1197 trace_spi_master_busy(master);
1198
1199 if (!was_busy && master->prepare_transfer_hardware) {
1200 ret = master->prepare_transfer_hardware(master);
1201 if (ret) {
1202 dev_err(&master->dev,
1203 "failed to prepare transfer hardware\n");
1204
1205 if (master->auto_runtime_pm)
1206 pm_runtime_put(master->dev.parent);
1207 mutex_unlock(&master->io_mutex);
1208 return;
1209 }
1210 }
1211
1212 trace_spi_message_start(master->cur_msg);
1213
1214 if (master->prepare_message) {
1215 ret = master->prepare_message(master, master->cur_msg);
1216 if (ret) {
1217 dev_err(&master->dev,
1218 "failed to prepare message: %d\n", ret);
1219 master->cur_msg->status = ret;
1220 spi_finalize_current_message(master);
1221 goto out;
1222 }
1223 master->cur_msg_prepared = true;
1224 }
1225
1226 ret = spi_map_msg(master, master->cur_msg);
1227 if (ret) {
1228 master->cur_msg->status = ret;
1229 spi_finalize_current_message(master);
1230 goto out;
1231 }
1232
1233 ret = master->transfer_one_message(master, master->cur_msg);
1234 if (ret) {
1235 dev_err(&master->dev,
1236 "failed to transfer one message from queue\n");
1237 goto out;
1238 }
1239
1240out:
1241 mutex_unlock(&master->io_mutex);
1242
1243 /* Prod the scheduler in case transfer_one() was busy waiting */
1244 if (!ret)
1245 cond_resched();
1246}
1247
1248/**
1249 * spi_pump_messages - kthread work function which processes spi message queue
1250 * @work: pointer to kthread work struct contained in the master struct
1251 */
1252static void spi_pump_messages(struct kthread_work *work)
1253{
1254 struct spi_master *master =
1255 container_of(work, struct spi_master, pump_messages);
1256
1257 __spi_pump_messages(master, true);
1258}
1259
1260static int spi_init_queue(struct spi_master *master)
1261{
1262 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1263
1264 master->running = false;
1265 master->busy = false;
1266
1267 kthread_init_worker(&master->kworker);
1268 master->kworker_task = kthread_run(kthread_worker_fn,
1269 &master->kworker, "%s",
1270 dev_name(&master->dev));
1271 if (IS_ERR(master->kworker_task)) {
1272 dev_err(&master->dev, "failed to create message pump task\n");
1273 return PTR_ERR(master->kworker_task);
1274 }
1275 kthread_init_work(&master->pump_messages, spi_pump_messages);
1276
1277 /*
1278 * Master config will indicate if this controller should run the
1279 * message pump with high (realtime) priority to reduce the transfer
1280 * latency on the bus by minimising the delay between a transfer
1281 * request and the scheduling of the message pump thread. Without this
1282 * setting the message pump thread will remain at default priority.
1283 */
1284 if (master->rt) {
1285 dev_info(&master->dev,
1286 "will run message pump with realtime priority\n");
1287 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1288 }
1289
1290 return 0;
1291}
1292
1293/**
1294 * spi_get_next_queued_message() - called by driver to check for queued
1295 * messages
1296 * @master: the master to check for queued messages
1297 *
1298 * If there are more messages in the queue, the next message is returned from
1299 * this call.
1300 *
1301 * Return: the next message in the queue, else NULL if the queue is empty.
1302 */
1303struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1304{
1305 struct spi_message *next;
1306 unsigned long flags;
1307
1308 /* get a pointer to the next message, if any */
1309 spin_lock_irqsave(&master->queue_lock, flags);
1310 next = list_first_entry_or_null(&master->queue, struct spi_message,
1311 queue);
1312 spin_unlock_irqrestore(&master->queue_lock, flags);
1313
1314 return next;
1315}
1316EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1317
1318/**
1319 * spi_finalize_current_message() - the current message is complete
1320 * @master: the master to return the message to
1321 *
1322 * Called by the driver to notify the core that the message in the front of the
1323 * queue is complete and can be removed from the queue.
1324 */
1325void spi_finalize_current_message(struct spi_master *master)
1326{
1327 struct spi_message *mesg;
1328 unsigned long flags;
1329 int ret;
1330
1331 spin_lock_irqsave(&master->queue_lock, flags);
1332 mesg = master->cur_msg;
1333 spin_unlock_irqrestore(&master->queue_lock, flags);
1334
1335 spi_unmap_msg(master, mesg);
1336
1337 if (master->cur_msg_prepared && master->unprepare_message) {
1338 ret = master->unprepare_message(master, mesg);
1339 if (ret) {
1340 dev_err(&master->dev,
1341 "failed to unprepare message: %d\n", ret);
1342 }
1343 }
1344
1345 spin_lock_irqsave(&master->queue_lock, flags);
1346 master->cur_msg = NULL;
1347 master->cur_msg_prepared = false;
1348 kthread_queue_work(&master->kworker, &master->pump_messages);
1349 spin_unlock_irqrestore(&master->queue_lock, flags);
1350
1351 trace_spi_message_done(mesg);
1352
1353 mesg->state = NULL;
1354 if (mesg->complete)
1355 mesg->complete(mesg->context);
1356}
1357EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1358
1359static int spi_start_queue(struct spi_master *master)
1360{
1361 unsigned long flags;
1362
1363 spin_lock_irqsave(&master->queue_lock, flags);
1364
1365 if (master->running || master->busy) {
1366 spin_unlock_irqrestore(&master->queue_lock, flags);
1367 return -EBUSY;
1368 }
1369
1370 master->running = true;
1371 master->cur_msg = NULL;
1372 spin_unlock_irqrestore(&master->queue_lock, flags);
1373
1374 kthread_queue_work(&master->kworker, &master->pump_messages);
1375
1376 return 0;
1377}
1378
1379static int spi_stop_queue(struct spi_master *master)
1380{
1381 unsigned long flags;
1382 unsigned limit = 500;
1383 int ret = 0;
1384
1385 spin_lock_irqsave(&master->queue_lock, flags);
1386
1387 /*
1388 * This is a bit lame, but is optimized for the common execution path.
1389 * A wait_queue on the master->busy could be used, but then the common
1390 * execution path (pump_messages) would be required to call wake_up or
1391 * friends on every SPI message. Do this instead.
1392 */
1393 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1394 spin_unlock_irqrestore(&master->queue_lock, flags);
1395 usleep_range(10000, 11000);
1396 spin_lock_irqsave(&master->queue_lock, flags);
1397 }
1398
1399 if (!list_empty(&master->queue) || master->busy)
1400 ret = -EBUSY;
1401 else
1402 master->running = false;
1403
1404 spin_unlock_irqrestore(&master->queue_lock, flags);
1405
1406 if (ret) {
1407 dev_warn(&master->dev,
1408 "could not stop message queue\n");
1409 return ret;
1410 }
1411 return ret;
1412}
1413
1414static int spi_destroy_queue(struct spi_master *master)
1415{
1416 int ret;
1417
1418 ret = spi_stop_queue(master);
1419
1420 /*
1421 * kthread_flush_worker will block until all work is done.
1422 * If the reason that stop_queue timed out is that the work will never
1423 * finish, then it does no good to call flush/stop thread, so
1424 * return anyway.
1425 */
1426 if (ret) {
1427 dev_err(&master->dev, "problem destroying queue\n");
1428 return ret;
1429 }
1430
1431 kthread_flush_worker(&master->kworker);
1432 kthread_stop(master->kworker_task);
1433
1434 return 0;
1435}
1436
1437static int __spi_queued_transfer(struct spi_device *spi,
1438 struct spi_message *msg,
1439 bool need_pump)
1440{
1441 struct spi_master *master = spi->master;
1442 unsigned long flags;
1443
1444 spin_lock_irqsave(&master->queue_lock, flags);
1445
1446 if (!master->running) {
1447 spin_unlock_irqrestore(&master->queue_lock, flags);
1448 return -ESHUTDOWN;
1449 }
1450 msg->actual_length = 0;
1451 msg->status = -EINPROGRESS;
1452
1453 list_add_tail(&msg->queue, &master->queue);
1454 if (!master->busy && need_pump)
1455 kthread_queue_work(&master->kworker, &master->pump_messages);
1456
1457 spin_unlock_irqrestore(&master->queue_lock, flags);
1458 return 0;
1459}
1460
1461/**
1462 * spi_queued_transfer - transfer function for queued transfers
1463 * @spi: spi device which is requesting transfer
1464 * @msg: spi message which is to handled is queued to driver queue
1465 *
1466 * Return: zero on success, else a negative error code.
1467 */
1468static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1469{
1470 return __spi_queued_transfer(spi, msg, true);
1471}
1472
1473static int spi_master_initialize_queue(struct spi_master *master)
1474{
1475 int ret;
1476
1477 master->transfer = spi_queued_transfer;
1478 if (!master->transfer_one_message)
1479 master->transfer_one_message = spi_transfer_one_message;
1480
1481 /* Initialize and start queue */
1482 ret = spi_init_queue(master);
1483 if (ret) {
1484 dev_err(&master->dev, "problem initializing queue\n");
1485 goto err_init_queue;
1486 }
1487 master->queued = true;
1488 ret = spi_start_queue(master);
1489 if (ret) {
1490 dev_err(&master->dev, "problem starting queue\n");
1491 goto err_start_queue;
1492 }
1493
1494 return 0;
1495
1496err_start_queue:
1497 spi_destroy_queue(master);
1498err_init_queue:
1499 return ret;
1500}
1501
1502/*-------------------------------------------------------------------------*/
1503
1504#if defined(CONFIG_OF)
1505static struct spi_device *
1506of_register_spi_device(struct spi_master *master, struct device_node *nc)
1507{
1508 struct spi_device *spi;
1509 int rc;
1510 u32 value;
1511
1512 /* Alloc an spi_device */
1513 spi = spi_alloc_device(master);
1514 if (!spi) {
1515 dev_err(&master->dev, "spi_device alloc error for %s\n",
1516 nc->full_name);
1517 rc = -ENOMEM;
1518 goto err_out;
1519 }
1520
1521 /* Select device driver */
1522 rc = of_modalias_node(nc, spi->modalias,
1523 sizeof(spi->modalias));
1524 if (rc < 0) {
1525 dev_err(&master->dev, "cannot find modalias for %s\n",
1526 nc->full_name);
1527 goto err_out;
1528 }
1529
1530 /* Device address */
1531 rc = of_property_read_u32(nc, "reg", &value);
1532 if (rc) {
1533 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1534 nc->full_name, rc);
1535 goto err_out;
1536 }
1537 spi->chip_select = value;
1538
1539 /* Mode (clock phase/polarity/etc.) */
1540 if (of_find_property(nc, "spi-cpha", NULL))
1541 spi->mode |= SPI_CPHA;
1542 if (of_find_property(nc, "spi-cpol", NULL))
1543 spi->mode |= SPI_CPOL;
1544 if (of_find_property(nc, "spi-cs-high", NULL))
1545 spi->mode |= SPI_CS_HIGH;
1546 if (of_find_property(nc, "spi-3wire", NULL))
1547 spi->mode |= SPI_3WIRE;
1548 if (of_find_property(nc, "spi-lsb-first", NULL))
1549 spi->mode |= SPI_LSB_FIRST;
1550
1551 /* Device DUAL/QUAD mode */
1552 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1553 switch (value) {
1554 case 1:
1555 break;
1556 case 2:
1557 spi->mode |= SPI_TX_DUAL;
1558 break;
1559 case 4:
1560 spi->mode |= SPI_TX_QUAD;
1561 break;
1562 default:
1563 dev_warn(&master->dev,
1564 "spi-tx-bus-width %d not supported\n",
1565 value);
1566 break;
1567 }
1568 }
1569
1570 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1571 switch (value) {
1572 case 1:
1573 break;
1574 case 2:
1575 spi->mode |= SPI_RX_DUAL;
1576 break;
1577 case 4:
1578 spi->mode |= SPI_RX_QUAD;
1579 break;
1580 default:
1581 dev_warn(&master->dev,
1582 "spi-rx-bus-width %d not supported\n",
1583 value);
1584 break;
1585 }
1586 }
1587
1588 /* Device speed */
1589 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1590 if (rc) {
1591 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1592 nc->full_name, rc);
1593 goto err_out;
1594 }
1595 spi->max_speed_hz = value;
1596
1597 /* Store a pointer to the node in the device structure */
1598 of_node_get(nc);
1599 spi->dev.of_node = nc;
1600
1601 /* Register the new device */
1602 rc = spi_add_device(spi);
1603 if (rc) {
1604 dev_err(&master->dev, "spi_device register error %s\n",
1605 nc->full_name);
1606 goto err_out;
1607 }
1608
1609 return spi;
1610
1611err_out:
1612 spi_dev_put(spi);
1613 return ERR_PTR(rc);
1614}
1615
1616/**
1617 * of_register_spi_devices() - Register child devices onto the SPI bus
1618 * @master: Pointer to spi_master device
1619 *
1620 * Registers an spi_device for each child node of master node which has a 'reg'
1621 * property.
1622 */
1623static void of_register_spi_devices(struct spi_master *master)
1624{
1625 struct spi_device *spi;
1626 struct device_node *nc;
1627
1628 if (!master->dev.of_node)
1629 return;
1630
1631 for_each_available_child_of_node(master->dev.of_node, nc) {
1632 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1633 continue;
1634 spi = of_register_spi_device(master, nc);
1635 if (IS_ERR(spi)) {
1636 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1637 nc->full_name);
1638 of_node_clear_flag(nc, OF_POPULATED);
1639 }
1640 }
1641}
1642#else
1643static void of_register_spi_devices(struct spi_master *master) { }
1644#endif
1645
1646#ifdef CONFIG_ACPI
1647static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1648{
1649 struct spi_device *spi = data;
1650 struct spi_master *master = spi->master;
1651
1652 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1653 struct acpi_resource_spi_serialbus *sb;
1654
1655 sb = &ares->data.spi_serial_bus;
1656 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1657 /*
1658 * ACPI DeviceSelection numbering is handled by the
1659 * host controller driver in Windows and can vary
1660 * from driver to driver. In Linux we always expect
1661 * 0 .. max - 1 so we need to ask the driver to
1662 * translate between the two schemes.
1663 */
1664 if (master->fw_translate_cs) {
1665 int cs = master->fw_translate_cs(master,
1666 sb->device_selection);
1667 if (cs < 0)
1668 return cs;
1669 spi->chip_select = cs;
1670 } else {
1671 spi->chip_select = sb->device_selection;
1672 }
1673
1674 spi->max_speed_hz = sb->connection_speed;
1675
1676 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1677 spi->mode |= SPI_CPHA;
1678 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1679 spi->mode |= SPI_CPOL;
1680 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1681 spi->mode |= SPI_CS_HIGH;
1682 }
1683 } else if (spi->irq < 0) {
1684 struct resource r;
1685
1686 if (acpi_dev_resource_interrupt(ares, 0, &r))
1687 spi->irq = r.start;
1688 }
1689
1690 /* Always tell the ACPI core to skip this resource */
1691 return 1;
1692}
1693
1694static acpi_status acpi_register_spi_device(struct spi_master *master,
1695 struct acpi_device *adev)
1696{
1697 struct list_head resource_list;
1698 struct spi_device *spi;
1699 int ret;
1700
1701 if (acpi_bus_get_status(adev) || !adev->status.present ||
1702 acpi_device_enumerated(adev))
1703 return AE_OK;
1704
1705 spi = spi_alloc_device(master);
1706 if (!spi) {
1707 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1708 dev_name(&adev->dev));
1709 return AE_NO_MEMORY;
1710 }
1711
1712 ACPI_COMPANION_SET(&spi->dev, adev);
1713 spi->irq = -1;
1714
1715 INIT_LIST_HEAD(&resource_list);
1716 ret = acpi_dev_get_resources(adev, &resource_list,
1717 acpi_spi_add_resource, spi);
1718 acpi_dev_free_resource_list(&resource_list);
1719
1720 if (ret < 0 || !spi->max_speed_hz) {
1721 spi_dev_put(spi);
1722 return AE_OK;
1723 }
1724
1725 if (spi->irq < 0)
1726 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1727
1728 acpi_device_set_enumerated(adev);
1729
1730 adev->power.flags.ignore_parent = true;
1731 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1732 if (spi_add_device(spi)) {
1733 adev->power.flags.ignore_parent = false;
1734 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1735 dev_name(&adev->dev));
1736 spi_dev_put(spi);
1737 }
1738
1739 return AE_OK;
1740}
1741
1742static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1743 void *data, void **return_value)
1744{
1745 struct spi_master *master = data;
1746 struct acpi_device *adev;
1747
1748 if (acpi_bus_get_device(handle, &adev))
1749 return AE_OK;
1750
1751 return acpi_register_spi_device(master, adev);
1752}
1753
1754static void acpi_register_spi_devices(struct spi_master *master)
1755{
1756 acpi_status status;
1757 acpi_handle handle;
1758
1759 handle = ACPI_HANDLE(master->dev.parent);
1760 if (!handle)
1761 return;
1762
1763 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1764 acpi_spi_add_device, NULL,
1765 master, NULL);
1766 if (ACPI_FAILURE(status))
1767 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1768}
1769#else
1770static inline void acpi_register_spi_devices(struct spi_master *master) {}
1771#endif /* CONFIG_ACPI */
1772
1773static void spi_master_release(struct device *dev)
1774{
1775 struct spi_master *master;
1776
1777 master = container_of(dev, struct spi_master, dev);
1778 kfree(master);
1779}
1780
1781static struct class spi_master_class = {
1782 .name = "spi_master",
1783 .owner = THIS_MODULE,
1784 .dev_release = spi_master_release,
1785 .dev_groups = spi_master_groups,
1786};
1787
1788
1789/**
1790 * spi_alloc_master - allocate SPI master controller
1791 * @dev: the controller, possibly using the platform_bus
1792 * @size: how much zeroed driver-private data to allocate; the pointer to this
1793 * memory is in the driver_data field of the returned device,
1794 * accessible with spi_master_get_devdata().
1795 * Context: can sleep
1796 *
1797 * This call is used only by SPI master controller drivers, which are the
1798 * only ones directly touching chip registers. It's how they allocate
1799 * an spi_master structure, prior to calling spi_register_master().
1800 *
1801 * This must be called from context that can sleep.
1802 *
1803 * The caller is responsible for assigning the bus number and initializing
1804 * the master's methods before calling spi_register_master(); and (after errors
1805 * adding the device) calling spi_master_put() to prevent a memory leak.
1806 *
1807 * Return: the SPI master structure on success, else NULL.
1808 */
1809struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1810{
1811 struct spi_master *master;
1812
1813 if (!dev)
1814 return NULL;
1815
1816 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1817 if (!master)
1818 return NULL;
1819
1820 device_initialize(&master->dev);
1821 master->bus_num = -1;
1822 master->num_chipselect = 1;
1823 master->dev.class = &spi_master_class;
1824 master->dev.parent = dev;
1825 pm_suspend_ignore_children(&master->dev, true);
1826 spi_master_set_devdata(master, &master[1]);
1827
1828 return master;
1829}
1830EXPORT_SYMBOL_GPL(spi_alloc_master);
1831
1832#ifdef CONFIG_OF
1833static int of_spi_register_master(struct spi_master *master)
1834{
1835 int nb, i, *cs;
1836 struct device_node *np = master->dev.of_node;
1837
1838 if (!np)
1839 return 0;
1840
1841 nb = of_gpio_named_count(np, "cs-gpios");
1842 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1843
1844 /* Return error only for an incorrectly formed cs-gpios property */
1845 if (nb == 0 || nb == -ENOENT)
1846 return 0;
1847 else if (nb < 0)
1848 return nb;
1849
1850 cs = devm_kzalloc(&master->dev,
1851 sizeof(int) * master->num_chipselect,
1852 GFP_KERNEL);
1853 master->cs_gpios = cs;
1854
1855 if (!master->cs_gpios)
1856 return -ENOMEM;
1857
1858 for (i = 0; i < master->num_chipselect; i++)
1859 cs[i] = -ENOENT;
1860
1861 for (i = 0; i < nb; i++)
1862 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1863
1864 return 0;
1865}
1866#else
1867static int of_spi_register_master(struct spi_master *master)
1868{
1869 return 0;
1870}
1871#endif
1872
1873/**
1874 * spi_register_master - register SPI master controller
1875 * @master: initialized master, originally from spi_alloc_master()
1876 * Context: can sleep
1877 *
1878 * SPI master controllers connect to their drivers using some non-SPI bus,
1879 * such as the platform bus. The final stage of probe() in that code
1880 * includes calling spi_register_master() to hook up to this SPI bus glue.
1881 *
1882 * SPI controllers use board specific (often SOC specific) bus numbers,
1883 * and board-specific addressing for SPI devices combines those numbers
1884 * with chip select numbers. Since SPI does not directly support dynamic
1885 * device identification, boards need configuration tables telling which
1886 * chip is at which address.
1887 *
1888 * This must be called from context that can sleep. It returns zero on
1889 * success, else a negative error code (dropping the master's refcount).
1890 * After a successful return, the caller is responsible for calling
1891 * spi_unregister_master().
1892 *
1893 * Return: zero on success, else a negative error code.
1894 */
1895int spi_register_master(struct spi_master *master)
1896{
1897 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1898 struct device *dev = master->dev.parent;
1899 struct boardinfo *bi;
1900 int status = -ENODEV;
1901 int dynamic = 0;
1902
1903 if (!dev)
1904 return -ENODEV;
1905
1906 status = of_spi_register_master(master);
1907 if (status)
1908 return status;
1909
1910 /* even if it's just one always-selected device, there must
1911 * be at least one chipselect
1912 */
1913 if (master->num_chipselect == 0)
1914 return -EINVAL;
1915
1916 if ((master->bus_num < 0) && master->dev.of_node)
1917 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1918
1919 /* convention: dynamically assigned bus IDs count down from the max */
1920 if (master->bus_num < 0) {
1921 /* FIXME switch to an IDR based scheme, something like
1922 * I2C now uses, so we can't run out of "dynamic" IDs
1923 */
1924 master->bus_num = atomic_dec_return(&dyn_bus_id);
1925 dynamic = 1;
1926 }
1927
1928 INIT_LIST_HEAD(&master->queue);
1929 spin_lock_init(&master->queue_lock);
1930 spin_lock_init(&master->bus_lock_spinlock);
1931 mutex_init(&master->bus_lock_mutex);
1932 mutex_init(&master->io_mutex);
1933 master->bus_lock_flag = 0;
1934 init_completion(&master->xfer_completion);
1935 if (!master->max_dma_len)
1936 master->max_dma_len = INT_MAX;
1937
1938 /* register the device, then userspace will see it.
1939 * registration fails if the bus ID is in use.
1940 */
1941 dev_set_name(&master->dev, "spi%u", master->bus_num);
1942 status = device_add(&master->dev);
1943 if (status < 0)
1944 goto done;
1945 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1946 dynamic ? " (dynamic)" : "");
1947
1948 /* If we're using a queued driver, start the queue */
1949 if (master->transfer)
1950 dev_info(dev, "master is unqueued, this is deprecated\n");
1951 else {
1952 status = spi_master_initialize_queue(master);
1953 if (status) {
1954 device_del(&master->dev);
1955 goto done;
1956 }
1957 }
1958 /* add statistics */
1959 spin_lock_init(&master->statistics.lock);
1960
1961 mutex_lock(&board_lock);
1962 list_add_tail(&master->list, &spi_master_list);
1963 list_for_each_entry(bi, &board_list, list)
1964 spi_match_master_to_boardinfo(master, &bi->board_info);
1965 mutex_unlock(&board_lock);
1966
1967 /* Register devices from the device tree and ACPI */
1968 of_register_spi_devices(master);
1969 acpi_register_spi_devices(master);
1970done:
1971 return status;
1972}
1973EXPORT_SYMBOL_GPL(spi_register_master);
1974
1975static void devm_spi_unregister(struct device *dev, void *res)
1976{
1977 spi_unregister_master(*(struct spi_master **)res);
1978}
1979
1980/**
1981 * dev_spi_register_master - register managed SPI master controller
1982 * @dev: device managing SPI master
1983 * @master: initialized master, originally from spi_alloc_master()
1984 * Context: can sleep
1985 *
1986 * Register a SPI device as with spi_register_master() which will
1987 * automatically be unregister
1988 *
1989 * Return: zero on success, else a negative error code.
1990 */
1991int devm_spi_register_master(struct device *dev, struct spi_master *master)
1992{
1993 struct spi_master **ptr;
1994 int ret;
1995
1996 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1997 if (!ptr)
1998 return -ENOMEM;
1999
2000 ret = spi_register_master(master);
2001 if (!ret) {
2002 *ptr = master;
2003 devres_add(dev, ptr);
2004 } else {
2005 devres_free(ptr);
2006 }
2007
2008 return ret;
2009}
2010EXPORT_SYMBOL_GPL(devm_spi_register_master);
2011
2012static int __unregister(struct device *dev, void *null)
2013{
2014 spi_unregister_device(to_spi_device(dev));
2015 return 0;
2016}
2017
2018/**
2019 * spi_unregister_master - unregister SPI master controller
2020 * @master: the master being unregistered
2021 * Context: can sleep
2022 *
2023 * This call is used only by SPI master controller drivers, which are the
2024 * only ones directly touching chip registers.
2025 *
2026 * This must be called from context that can sleep.
2027 */
2028void spi_unregister_master(struct spi_master *master)
2029{
2030 int dummy;
2031
2032 if (master->queued) {
2033 if (spi_destroy_queue(master))
2034 dev_err(&master->dev, "queue remove failed\n");
2035 }
2036
2037 mutex_lock(&board_lock);
2038 list_del(&master->list);
2039 mutex_unlock(&board_lock);
2040
2041 dummy = device_for_each_child(&master->dev, NULL, __unregister);
2042 device_unregister(&master->dev);
2043}
2044EXPORT_SYMBOL_GPL(spi_unregister_master);
2045
2046int spi_master_suspend(struct spi_master *master)
2047{
2048 int ret;
2049
2050 /* Basically no-ops for non-queued masters */
2051 if (!master->queued)
2052 return 0;
2053
2054 ret = spi_stop_queue(master);
2055 if (ret)
2056 dev_err(&master->dev, "queue stop failed\n");
2057
2058 return ret;
2059}
2060EXPORT_SYMBOL_GPL(spi_master_suspend);
2061
2062int spi_master_resume(struct spi_master *master)
2063{
2064 int ret;
2065
2066 if (!master->queued)
2067 return 0;
2068
2069 ret = spi_start_queue(master);
2070 if (ret)
2071 dev_err(&master->dev, "queue restart failed\n");
2072
2073 return ret;
2074}
2075EXPORT_SYMBOL_GPL(spi_master_resume);
2076
2077static int __spi_master_match(struct device *dev, const void *data)
2078{
2079 struct spi_master *m;
2080 const u16 *bus_num = data;
2081
2082 m = container_of(dev, struct spi_master, dev);
2083 return m->bus_num == *bus_num;
2084}
2085
2086/**
2087 * spi_busnum_to_master - look up master associated with bus_num
2088 * @bus_num: the master's bus number
2089 * Context: can sleep
2090 *
2091 * This call may be used with devices that are registered after
2092 * arch init time. It returns a refcounted pointer to the relevant
2093 * spi_master (which the caller must release), or NULL if there is
2094 * no such master registered.
2095 *
2096 * Return: the SPI master structure on success, else NULL.
2097 */
2098struct spi_master *spi_busnum_to_master(u16 bus_num)
2099{
2100 struct device *dev;
2101 struct spi_master *master = NULL;
2102
2103 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2104 __spi_master_match);
2105 if (dev)
2106 master = container_of(dev, struct spi_master, dev);
2107 /* reference got in class_find_device */
2108 return master;
2109}
2110EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2111
2112/*-------------------------------------------------------------------------*/
2113
2114/* Core methods for SPI resource management */
2115
2116/**
2117 * spi_res_alloc - allocate a spi resource that is life-cycle managed
2118 * during the processing of a spi_message while using
2119 * spi_transfer_one
2120 * @spi: the spi device for which we allocate memory
2121 * @release: the release code to execute for this resource
2122 * @size: size to alloc and return
2123 * @gfp: GFP allocation flags
2124 *
2125 * Return: the pointer to the allocated data
2126 *
2127 * This may get enhanced in the future to allocate from a memory pool
2128 * of the @spi_device or @spi_master to avoid repeated allocations.
2129 */
2130void *spi_res_alloc(struct spi_device *spi,
2131 spi_res_release_t release,
2132 size_t size, gfp_t gfp)
2133{
2134 struct spi_res *sres;
2135
2136 sres = kzalloc(sizeof(*sres) + size, gfp);
2137 if (!sres)
2138 return NULL;
2139
2140 INIT_LIST_HEAD(&sres->entry);
2141 sres->release = release;
2142
2143 return sres->data;
2144}
2145EXPORT_SYMBOL_GPL(spi_res_alloc);
2146
2147/**
2148 * spi_res_free - free an spi resource
2149 * @res: pointer to the custom data of a resource
2150 *
2151 */
2152void spi_res_free(void *res)
2153{
2154 struct spi_res *sres = container_of(res, struct spi_res, data);
2155
2156 if (!res)
2157 return;
2158
2159 WARN_ON(!list_empty(&sres->entry));
2160 kfree(sres);
2161}
2162EXPORT_SYMBOL_GPL(spi_res_free);
2163
2164/**
2165 * spi_res_add - add a spi_res to the spi_message
2166 * @message: the spi message
2167 * @res: the spi_resource
2168 */
2169void spi_res_add(struct spi_message *message, void *res)
2170{
2171 struct spi_res *sres = container_of(res, struct spi_res, data);
2172
2173 WARN_ON(!list_empty(&sres->entry));
2174 list_add_tail(&sres->entry, &message->resources);
2175}
2176EXPORT_SYMBOL_GPL(spi_res_add);
2177
2178/**
2179 * spi_res_release - release all spi resources for this message
2180 * @master: the @spi_master
2181 * @message: the @spi_message
2182 */
2183void spi_res_release(struct spi_master *master,
2184 struct spi_message *message)
2185{
2186 struct spi_res *res;
2187
2188 while (!list_empty(&message->resources)) {
2189 res = list_last_entry(&message->resources,
2190 struct spi_res, entry);
2191
2192 if (res->release)
2193 res->release(master, message, res->data);
2194
2195 list_del(&res->entry);
2196
2197 kfree(res);
2198 }
2199}
2200EXPORT_SYMBOL_GPL(spi_res_release);
2201
2202/*-------------------------------------------------------------------------*/
2203
2204/* Core methods for spi_message alterations */
2205
2206static void __spi_replace_transfers_release(struct spi_master *master,
2207 struct spi_message *msg,
2208 void *res)
2209{
2210 struct spi_replaced_transfers *rxfer = res;
2211 size_t i;
2212
2213 /* call extra callback if requested */
2214 if (rxfer->release)
2215 rxfer->release(master, msg, res);
2216
2217 /* insert replaced transfers back into the message */
2218 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2219
2220 /* remove the formerly inserted entries */
2221 for (i = 0; i < rxfer->inserted; i++)
2222 list_del(&rxfer->inserted_transfers[i].transfer_list);
2223}
2224
2225/**
2226 * spi_replace_transfers - replace transfers with several transfers
2227 * and register change with spi_message.resources
2228 * @msg: the spi_message we work upon
2229 * @xfer_first: the first spi_transfer we want to replace
2230 * @remove: number of transfers to remove
2231 * @insert: the number of transfers we want to insert instead
2232 * @release: extra release code necessary in some circumstances
2233 * @extradatasize: extra data to allocate (with alignment guarantees
2234 * of struct @spi_transfer)
2235 * @gfp: gfp flags
2236 *
2237 * Returns: pointer to @spi_replaced_transfers,
2238 * PTR_ERR(...) in case of errors.
2239 */
2240struct spi_replaced_transfers *spi_replace_transfers(
2241 struct spi_message *msg,
2242 struct spi_transfer *xfer_first,
2243 size_t remove,
2244 size_t insert,
2245 spi_replaced_release_t release,
2246 size_t extradatasize,
2247 gfp_t gfp)
2248{
2249 struct spi_replaced_transfers *rxfer;
2250 struct spi_transfer *xfer;
2251 size_t i;
2252
2253 /* allocate the structure using spi_res */
2254 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2255 insert * sizeof(struct spi_transfer)
2256 + sizeof(struct spi_replaced_transfers)
2257 + extradatasize,
2258 gfp);
2259 if (!rxfer)
2260 return ERR_PTR(-ENOMEM);
2261
2262 /* the release code to invoke before running the generic release */
2263 rxfer->release = release;
2264
2265 /* assign extradata */
2266 if (extradatasize)
2267 rxfer->extradata =
2268 &rxfer->inserted_transfers[insert];
2269
2270 /* init the replaced_transfers list */
2271 INIT_LIST_HEAD(&rxfer->replaced_transfers);
2272
2273 /* assign the list_entry after which we should reinsert
2274 * the @replaced_transfers - it may be spi_message.messages!
2275 */
2276 rxfer->replaced_after = xfer_first->transfer_list.prev;
2277
2278 /* remove the requested number of transfers */
2279 for (i = 0; i < remove; i++) {
2280 /* if the entry after replaced_after it is msg->transfers
2281 * then we have been requested to remove more transfers
2282 * than are in the list
2283 */
2284 if (rxfer->replaced_after->next == &msg->transfers) {
2285 dev_err(&msg->spi->dev,
2286 "requested to remove more spi_transfers than are available\n");
2287 /* insert replaced transfers back into the message */
2288 list_splice(&rxfer->replaced_transfers,
2289 rxfer->replaced_after);
2290
2291 /* free the spi_replace_transfer structure */
2292 spi_res_free(rxfer);
2293
2294 /* and return with an error */
2295 return ERR_PTR(-EINVAL);
2296 }
2297
2298 /* remove the entry after replaced_after from list of
2299 * transfers and add it to list of replaced_transfers
2300 */
2301 list_move_tail(rxfer->replaced_after->next,
2302 &rxfer->replaced_transfers);
2303 }
2304
2305 /* create copy of the given xfer with identical settings
2306 * based on the first transfer to get removed
2307 */
2308 for (i = 0; i < insert; i++) {
2309 /* we need to run in reverse order */
2310 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2311
2312 /* copy all spi_transfer data */
2313 memcpy(xfer, xfer_first, sizeof(*xfer));
2314
2315 /* add to list */
2316 list_add(&xfer->transfer_list, rxfer->replaced_after);
2317
2318 /* clear cs_change and delay_usecs for all but the last */
2319 if (i) {
2320 xfer->cs_change = false;
2321 xfer->delay_usecs = 0;
2322 }
2323 }
2324
2325 /* set up inserted */
2326 rxfer->inserted = insert;
2327
2328 /* and register it with spi_res/spi_message */
2329 spi_res_add(msg, rxfer);
2330
2331 return rxfer;
2332}
2333EXPORT_SYMBOL_GPL(spi_replace_transfers);
2334
2335static int __spi_split_transfer_maxsize(struct spi_master *master,
2336 struct spi_message *msg,
2337 struct spi_transfer **xferp,
2338 size_t maxsize,
2339 gfp_t gfp)
2340{
2341 struct spi_transfer *xfer = *xferp, *xfers;
2342 struct spi_replaced_transfers *srt;
2343 size_t offset;
2344 size_t count, i;
2345
2346 /* warn once about this fact that we are splitting a transfer */
2347 dev_warn_once(&msg->spi->dev,
2348 "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2349 xfer->len, maxsize);
2350
2351 /* calculate how many we have to replace */
2352 count = DIV_ROUND_UP(xfer->len, maxsize);
2353
2354 /* create replacement */
2355 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2356 if (IS_ERR(srt))
2357 return PTR_ERR(srt);
2358 xfers = srt->inserted_transfers;
2359
2360 /* now handle each of those newly inserted spi_transfers
2361 * note that the replacements spi_transfers all are preset
2362 * to the same values as *xferp, so tx_buf, rx_buf and len
2363 * are all identical (as well as most others)
2364 * so we just have to fix up len and the pointers.
2365 *
2366 * this also includes support for the depreciated
2367 * spi_message.is_dma_mapped interface
2368 */
2369
2370 /* the first transfer just needs the length modified, so we
2371 * run it outside the loop
2372 */
2373 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2374
2375 /* all the others need rx_buf/tx_buf also set */
2376 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2377 /* update rx_buf, tx_buf and dma */
2378 if (xfers[i].rx_buf)
2379 xfers[i].rx_buf += offset;
2380 if (xfers[i].rx_dma)
2381 xfers[i].rx_dma += offset;
2382 if (xfers[i].tx_buf)
2383 xfers[i].tx_buf += offset;
2384 if (xfers[i].tx_dma)
2385 xfers[i].tx_dma += offset;
2386
2387 /* update length */
2388 xfers[i].len = min(maxsize, xfers[i].len - offset);
2389 }
2390
2391 /* we set up xferp to the last entry we have inserted,
2392 * so that we skip those already split transfers
2393 */
2394 *xferp = &xfers[count - 1];
2395
2396 /* increment statistics counters */
2397 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2398 transfers_split_maxsize);
2399 SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2400 transfers_split_maxsize);
2401
2402 return 0;
2403}
2404
2405/**
2406 * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2407 * when an individual transfer exceeds a
2408 * certain size
2409 * @master: the @spi_master for this transfer
2410 * @msg: the @spi_message to transform
2411 * @maxsize: the maximum when to apply this
2412 * @gfp: GFP allocation flags
2413 *
2414 * Return: status of transformation
2415 */
2416int spi_split_transfers_maxsize(struct spi_master *master,
2417 struct spi_message *msg,
2418 size_t maxsize,
2419 gfp_t gfp)
2420{
2421 struct spi_transfer *xfer;
2422 int ret;
2423
2424 /* iterate over the transfer_list,
2425 * but note that xfer is advanced to the last transfer inserted
2426 * to avoid checking sizes again unnecessarily (also xfer does
2427 * potentiall belong to a different list by the time the
2428 * replacement has happened
2429 */
2430 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2431 if (xfer->len > maxsize) {
2432 ret = __spi_split_transfer_maxsize(
2433 master, msg, &xfer, maxsize, gfp);
2434 if (ret)
2435 return ret;
2436 }
2437 }
2438
2439 return 0;
2440}
2441EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2442
2443/*-------------------------------------------------------------------------*/
2444
2445/* Core methods for SPI master protocol drivers. Some of the
2446 * other core methods are currently defined as inline functions.
2447 */
2448
2449static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2450{
2451 if (master->bits_per_word_mask) {
2452 /* Only 32 bits fit in the mask */
2453 if (bits_per_word > 32)
2454 return -EINVAL;
2455 if (!(master->bits_per_word_mask &
2456 SPI_BPW_MASK(bits_per_word)))
2457 return -EINVAL;
2458 }
2459
2460 return 0;
2461}
2462
2463/**
2464 * spi_setup - setup SPI mode and clock rate
2465 * @spi: the device whose settings are being modified
2466 * Context: can sleep, and no requests are queued to the device
2467 *
2468 * SPI protocol drivers may need to update the transfer mode if the
2469 * device doesn't work with its default. They may likewise need
2470 * to update clock rates or word sizes from initial values. This function
2471 * changes those settings, and must be called from a context that can sleep.
2472 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2473 * effect the next time the device is selected and data is transferred to
2474 * or from it. When this function returns, the spi device is deselected.
2475 *
2476 * Note that this call will fail if the protocol driver specifies an option
2477 * that the underlying controller or its driver does not support. For
2478 * example, not all hardware supports wire transfers using nine bit words,
2479 * LSB-first wire encoding, or active-high chipselects.
2480 *
2481 * Return: zero on success, else a negative error code.
2482 */
2483int spi_setup(struct spi_device *spi)
2484{
2485 unsigned bad_bits, ugly_bits;
2486 int status;
2487
2488 /* check mode to prevent that DUAL and QUAD set at the same time
2489 */
2490 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2491 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2492 dev_err(&spi->dev,
2493 "setup: can not select dual and quad at the same time\n");
2494 return -EINVAL;
2495 }
2496 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2497 */
2498 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2499 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2500 return -EINVAL;
2501 /* help drivers fail *cleanly* when they need options
2502 * that aren't supported with their current master
2503 */
2504 bad_bits = spi->mode & ~spi->master->mode_bits;
2505 ugly_bits = bad_bits &
2506 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2507 if (ugly_bits) {
2508 dev_warn(&spi->dev,
2509 "setup: ignoring unsupported mode bits %x\n",
2510 ugly_bits);
2511 spi->mode &= ~ugly_bits;
2512 bad_bits &= ~ugly_bits;
2513 }
2514 if (bad_bits) {
2515 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2516 bad_bits);
2517 return -EINVAL;
2518 }
2519
2520 if (!spi->bits_per_word)
2521 spi->bits_per_word = 8;
2522
2523 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2524 if (status)
2525 return status;
2526
2527 if (!spi->max_speed_hz)
2528 spi->max_speed_hz = spi->master->max_speed_hz;
2529
2530 if (spi->master->setup)
2531 status = spi->master->setup(spi);
2532
2533 spi_set_cs(spi, false);
2534
2535 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2536 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2537 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2538 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2539 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2540 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2541 spi->bits_per_word, spi->max_speed_hz,
2542 status);
2543
2544 return status;
2545}
2546EXPORT_SYMBOL_GPL(spi_setup);
2547
2548static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2549{
2550 struct spi_master *master = spi->master;
2551 struct spi_transfer *xfer;
2552 int w_size;
2553
2554 if (list_empty(&message->transfers))
2555 return -EINVAL;
2556
2557 /* Half-duplex links include original MicroWire, and ones with
2558 * only one data pin like SPI_3WIRE (switches direction) or where
2559 * either MOSI or MISO is missing. They can also be caused by
2560 * software limitations.
2561 */
2562 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2563 || (spi->mode & SPI_3WIRE)) {
2564 unsigned flags = master->flags;
2565
2566 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2567 if (xfer->rx_buf && xfer->tx_buf)
2568 return -EINVAL;
2569 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2570 return -EINVAL;
2571 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2572 return -EINVAL;
2573 }
2574 }
2575
2576 /**
2577 * Set transfer bits_per_word and max speed as spi device default if
2578 * it is not set for this transfer.
2579 * Set transfer tx_nbits and rx_nbits as single transfer default
2580 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2581 */
2582 message->frame_length = 0;
2583 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2584 message->frame_length += xfer->len;
2585 if (!xfer->bits_per_word)
2586 xfer->bits_per_word = spi->bits_per_word;
2587
2588 if (!xfer->speed_hz)
2589 xfer->speed_hz = spi->max_speed_hz;
2590 if (!xfer->speed_hz)
2591 xfer->speed_hz = master->max_speed_hz;
2592
2593 if (master->max_speed_hz &&
2594 xfer->speed_hz > master->max_speed_hz)
2595 xfer->speed_hz = master->max_speed_hz;
2596
2597 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2598 return -EINVAL;
2599
2600 /*
2601 * SPI transfer length should be multiple of SPI word size
2602 * where SPI word size should be power-of-two multiple
2603 */
2604 if (xfer->bits_per_word <= 8)
2605 w_size = 1;
2606 else if (xfer->bits_per_word <= 16)
2607 w_size = 2;
2608 else
2609 w_size = 4;
2610
2611 /* No partial transfers accepted */
2612 if (xfer->len % w_size)
2613 return -EINVAL;
2614
2615 if (xfer->speed_hz && master->min_speed_hz &&
2616 xfer->speed_hz < master->min_speed_hz)
2617 return -EINVAL;
2618
2619 if (xfer->tx_buf && !xfer->tx_nbits)
2620 xfer->tx_nbits = SPI_NBITS_SINGLE;
2621 if (xfer->rx_buf && !xfer->rx_nbits)
2622 xfer->rx_nbits = SPI_NBITS_SINGLE;
2623 /* check transfer tx/rx_nbits:
2624 * 1. check the value matches one of single, dual and quad
2625 * 2. check tx/rx_nbits match the mode in spi_device
2626 */
2627 if (xfer->tx_buf) {
2628 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2629 xfer->tx_nbits != SPI_NBITS_DUAL &&
2630 xfer->tx_nbits != SPI_NBITS_QUAD)
2631 return -EINVAL;
2632 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2633 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2634 return -EINVAL;
2635 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2636 !(spi->mode & SPI_TX_QUAD))
2637 return -EINVAL;
2638 }
2639 /* check transfer rx_nbits */
2640 if (xfer->rx_buf) {
2641 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2642 xfer->rx_nbits != SPI_NBITS_DUAL &&
2643 xfer->rx_nbits != SPI_NBITS_QUAD)
2644 return -EINVAL;
2645 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2646 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2647 return -EINVAL;
2648 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2649 !(spi->mode & SPI_RX_QUAD))
2650 return -EINVAL;
2651 }
2652 }
2653
2654 message->status = -EINPROGRESS;
2655
2656 return 0;
2657}
2658
2659static int __spi_async(struct spi_device *spi, struct spi_message *message)
2660{
2661 struct spi_master *master = spi->master;
2662
2663 message->spi = spi;
2664
2665 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2666 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2667
2668 trace_spi_message_submit(message);
2669
2670 return master->transfer(spi, message);
2671}
2672
2673/**
2674 * spi_async - asynchronous SPI transfer
2675 * @spi: device with which data will be exchanged
2676 * @message: describes the data transfers, including completion callback
2677 * Context: any (irqs may be blocked, etc)
2678 *
2679 * This call may be used in_irq and other contexts which can't sleep,
2680 * as well as from task contexts which can sleep.
2681 *
2682 * The completion callback is invoked in a context which can't sleep.
2683 * Before that invocation, the value of message->status is undefined.
2684 * When the callback is issued, message->status holds either zero (to
2685 * indicate complete success) or a negative error code. After that
2686 * callback returns, the driver which issued the transfer request may
2687 * deallocate the associated memory; it's no longer in use by any SPI
2688 * core or controller driver code.
2689 *
2690 * Note that although all messages to a spi_device are handled in
2691 * FIFO order, messages may go to different devices in other orders.
2692 * Some device might be higher priority, or have various "hard" access
2693 * time requirements, for example.
2694 *
2695 * On detection of any fault during the transfer, processing of
2696 * the entire message is aborted, and the device is deselected.
2697 * Until returning from the associated message completion callback,
2698 * no other spi_message queued to that device will be processed.
2699 * (This rule applies equally to all the synchronous transfer calls,
2700 * which are wrappers around this core asynchronous primitive.)
2701 *
2702 * Return: zero on success, else a negative error code.
2703 */
2704int spi_async(struct spi_device *spi, struct spi_message *message)
2705{
2706 struct spi_master *master = spi->master;
2707 int ret;
2708 unsigned long flags;
2709
2710 ret = __spi_validate(spi, message);
2711 if (ret != 0)
2712 return ret;
2713
2714 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2715
2716 if (master->bus_lock_flag)
2717 ret = -EBUSY;
2718 else
2719 ret = __spi_async(spi, message);
2720
2721 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2722
2723 return ret;
2724}
2725EXPORT_SYMBOL_GPL(spi_async);
2726
2727/**
2728 * spi_async_locked - version of spi_async with exclusive bus usage
2729 * @spi: device with which data will be exchanged
2730 * @message: describes the data transfers, including completion callback
2731 * Context: any (irqs may be blocked, etc)
2732 *
2733 * This call may be used in_irq and other contexts which can't sleep,
2734 * as well as from task contexts which can sleep.
2735 *
2736 * The completion callback is invoked in a context which can't sleep.
2737 * Before that invocation, the value of message->status is undefined.
2738 * When the callback is issued, message->status holds either zero (to
2739 * indicate complete success) or a negative error code. After that
2740 * callback returns, the driver which issued the transfer request may
2741 * deallocate the associated memory; it's no longer in use by any SPI
2742 * core or controller driver code.
2743 *
2744 * Note that although all messages to a spi_device are handled in
2745 * FIFO order, messages may go to different devices in other orders.
2746 * Some device might be higher priority, or have various "hard" access
2747 * time requirements, for example.
2748 *
2749 * On detection of any fault during the transfer, processing of
2750 * the entire message is aborted, and the device is deselected.
2751 * Until returning from the associated message completion callback,
2752 * no other spi_message queued to that device will be processed.
2753 * (This rule applies equally to all the synchronous transfer calls,
2754 * which are wrappers around this core asynchronous primitive.)
2755 *
2756 * Return: zero on success, else a negative error code.
2757 */
2758int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2759{
2760 struct spi_master *master = spi->master;
2761 int ret;
2762 unsigned long flags;
2763
2764 ret = __spi_validate(spi, message);
2765 if (ret != 0)
2766 return ret;
2767
2768 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2769
2770 ret = __spi_async(spi, message);
2771
2772 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2773
2774 return ret;
2775
2776}
2777EXPORT_SYMBOL_GPL(spi_async_locked);
2778
2779
2780int spi_flash_read(struct spi_device *spi,
2781 struct spi_flash_read_message *msg)
2782
2783{
2784 struct spi_master *master = spi->master;
2785 struct device *rx_dev = NULL;
2786 int ret;
2787
2788 if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2789 msg->addr_nbits == SPI_NBITS_DUAL) &&
2790 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2791 return -EINVAL;
2792 if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2793 msg->addr_nbits == SPI_NBITS_QUAD) &&
2794 !(spi->mode & SPI_TX_QUAD))
2795 return -EINVAL;
2796 if (msg->data_nbits == SPI_NBITS_DUAL &&
2797 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2798 return -EINVAL;
2799 if (msg->data_nbits == SPI_NBITS_QUAD &&
2800 !(spi->mode & SPI_RX_QUAD))
2801 return -EINVAL;
2802
2803 if (master->auto_runtime_pm) {
2804 ret = pm_runtime_get_sync(master->dev.parent);
2805 if (ret < 0) {
2806 dev_err(&master->dev, "Failed to power device: %d\n",
2807 ret);
2808 return ret;
2809 }
2810 }
2811
2812 mutex_lock(&master->bus_lock_mutex);
2813 mutex_lock(&master->io_mutex);
2814 if (master->dma_rx) {
2815 rx_dev = master->dma_rx->device->dev;
2816 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2817 msg->buf, msg->len,
2818 DMA_FROM_DEVICE);
2819 if (!ret)
2820 msg->cur_msg_mapped = true;
2821 }
2822 ret = master->spi_flash_read(spi, msg);
2823 if (msg->cur_msg_mapped)
2824 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2825 DMA_FROM_DEVICE);
2826 mutex_unlock(&master->io_mutex);
2827 mutex_unlock(&master->bus_lock_mutex);
2828
2829 if (master->auto_runtime_pm)
2830 pm_runtime_put(master->dev.parent);
2831
2832 return ret;
2833}
2834EXPORT_SYMBOL_GPL(spi_flash_read);
2835
2836/*-------------------------------------------------------------------------*/
2837
2838/* Utility methods for SPI master protocol drivers, layered on
2839 * top of the core. Some other utility methods are defined as
2840 * inline functions.
2841 */
2842
2843static void spi_complete(void *arg)
2844{
2845 complete(arg);
2846}
2847
2848static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2849{
2850 DECLARE_COMPLETION_ONSTACK(done);
2851 int status;
2852 struct spi_master *master = spi->master;
2853 unsigned long flags;
2854
2855 status = __spi_validate(spi, message);
2856 if (status != 0)
2857 return status;
2858
2859 message->complete = spi_complete;
2860 message->context = &done;
2861 message->spi = spi;
2862
2863 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2864 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2865
2866 /* If we're not using the legacy transfer method then we will
2867 * try to transfer in the calling context so special case.
2868 * This code would be less tricky if we could remove the
2869 * support for driver implemented message queues.
2870 */
2871 if (master->transfer == spi_queued_transfer) {
2872 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2873
2874 trace_spi_message_submit(message);
2875
2876 status = __spi_queued_transfer(spi, message, false);
2877
2878 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2879 } else {
2880 status = spi_async_locked(spi, message);
2881 }
2882
2883 if (status == 0) {
2884 /* Push out the messages in the calling context if we
2885 * can.
2886 */
2887 if (master->transfer == spi_queued_transfer) {
2888 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2889 spi_sync_immediate);
2890 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2891 spi_sync_immediate);
2892 __spi_pump_messages(master, false);
2893 }
2894
2895 wait_for_completion(&done);
2896 status = message->status;
2897 }
2898 message->context = NULL;
2899 return status;
2900}
2901
2902/**
2903 * spi_sync - blocking/synchronous SPI data transfers
2904 * @spi: device with which data will be exchanged
2905 * @message: describes the data transfers
2906 * Context: can sleep
2907 *
2908 * This call may only be used from a context that may sleep. The sleep
2909 * is non-interruptible, and has no timeout. Low-overhead controller
2910 * drivers may DMA directly into and out of the message buffers.
2911 *
2912 * Note that the SPI device's chip select is active during the message,
2913 * and then is normally disabled between messages. Drivers for some
2914 * frequently-used devices may want to minimize costs of selecting a chip,
2915 * by leaving it selected in anticipation that the next message will go
2916 * to the same chip. (That may increase power usage.)
2917 *
2918 * Also, the caller is guaranteeing that the memory associated with the
2919 * message will not be freed before this call returns.
2920 *
2921 * Return: zero on success, else a negative error code.
2922 */
2923int spi_sync(struct spi_device *spi, struct spi_message *message)
2924{
2925 int ret;
2926
2927 mutex_lock(&spi->master->bus_lock_mutex);
2928 ret = __spi_sync(spi, message);
2929 mutex_unlock(&spi->master->bus_lock_mutex);
2930
2931 return ret;
2932}
2933EXPORT_SYMBOL_GPL(spi_sync);
2934
2935/**
2936 * spi_sync_locked - version of spi_sync with exclusive bus usage
2937 * @spi: device with which data will be exchanged
2938 * @message: describes the data transfers
2939 * Context: can sleep
2940 *
2941 * This call may only be used from a context that may sleep. The sleep
2942 * is non-interruptible, and has no timeout. Low-overhead controller
2943 * drivers may DMA directly into and out of the message buffers.
2944 *
2945 * This call should be used by drivers that require exclusive access to the
2946 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2947 * be released by a spi_bus_unlock call when the exclusive access is over.
2948 *
2949 * Return: zero on success, else a negative error code.
2950 */
2951int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2952{
2953 return __spi_sync(spi, message);
2954}
2955EXPORT_SYMBOL_GPL(spi_sync_locked);
2956
2957/**
2958 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2959 * @master: SPI bus master that should be locked for exclusive bus access
2960 * Context: can sleep
2961 *
2962 * This call may only be used from a context that may sleep. The sleep
2963 * is non-interruptible, and has no timeout.
2964 *
2965 * This call should be used by drivers that require exclusive access to the
2966 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2967 * exclusive access is over. Data transfer must be done by spi_sync_locked
2968 * and spi_async_locked calls when the SPI bus lock is held.
2969 *
2970 * Return: always zero.
2971 */
2972int spi_bus_lock(struct spi_master *master)
2973{
2974 unsigned long flags;
2975
2976 mutex_lock(&master->bus_lock_mutex);
2977
2978 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2979 master->bus_lock_flag = 1;
2980 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2981
2982 /* mutex remains locked until spi_bus_unlock is called */
2983
2984 return 0;
2985}
2986EXPORT_SYMBOL_GPL(spi_bus_lock);
2987
2988/**
2989 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2990 * @master: SPI bus master that was locked for exclusive bus access
2991 * Context: can sleep
2992 *
2993 * This call may only be used from a context that may sleep. The sleep
2994 * is non-interruptible, and has no timeout.
2995 *
2996 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2997 * call.
2998 *
2999 * Return: always zero.
3000 */
3001int spi_bus_unlock(struct spi_master *master)
3002{
3003 master->bus_lock_flag = 0;
3004
3005 mutex_unlock(&master->bus_lock_mutex);
3006
3007 return 0;
3008}
3009EXPORT_SYMBOL_GPL(spi_bus_unlock);
3010
3011/* portable code must never pass more than 32 bytes */
3012#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
3013
3014static u8 *buf;
3015
3016/**
3017 * spi_write_then_read - SPI synchronous write followed by read
3018 * @spi: device with which data will be exchanged
3019 * @txbuf: data to be written (need not be dma-safe)
3020 * @n_tx: size of txbuf, in bytes
3021 * @rxbuf: buffer into which data will be read (need not be dma-safe)
3022 * @n_rx: size of rxbuf, in bytes
3023 * Context: can sleep
3024 *
3025 * This performs a half duplex MicroWire style transaction with the
3026 * device, sending txbuf and then reading rxbuf. The return value
3027 * is zero for success, else a negative errno status code.
3028 * This call may only be used from a context that may sleep.
3029 *
3030 * Parameters to this routine are always copied using a small buffer;
3031 * portable code should never use this for more than 32 bytes.
3032 * Performance-sensitive or bulk transfer code should instead use
3033 * spi_{async,sync}() calls with dma-safe buffers.
3034 *
3035 * Return: zero on success, else a negative error code.
3036 */
3037int spi_write_then_read(struct spi_device *spi,
3038 const void *txbuf, unsigned n_tx,
3039 void *rxbuf, unsigned n_rx)
3040{
3041 static DEFINE_MUTEX(lock);
3042
3043 int status;
3044 struct spi_message message;
3045 struct spi_transfer x[2];
3046 u8 *local_buf;
3047
3048 /* Use preallocated DMA-safe buffer if we can. We can't avoid
3049 * copying here, (as a pure convenience thing), but we can
3050 * keep heap costs out of the hot path unless someone else is
3051 * using the pre-allocated buffer or the transfer is too large.
3052 */
3053 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3054 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3055 GFP_KERNEL | GFP_DMA);
3056 if (!local_buf)
3057 return -ENOMEM;
3058 } else {
3059 local_buf = buf;
3060 }
3061
3062 spi_message_init(&message);
3063 memset(x, 0, sizeof(x));
3064 if (n_tx) {
3065 x[0].len = n_tx;
3066 spi_message_add_tail(&x[0], &message);
3067 }
3068 if (n_rx) {
3069 x[1].len = n_rx;
3070 spi_message_add_tail(&x[1], &message);
3071 }
3072
3073 memcpy(local_buf, txbuf, n_tx);
3074 x[0].tx_buf = local_buf;
3075 x[1].rx_buf = local_buf + n_tx;
3076
3077 /* do the i/o */
3078 status = spi_sync(spi, &message);
3079 if (status == 0)
3080 memcpy(rxbuf, x[1].rx_buf, n_rx);
3081
3082 if (x[0].tx_buf == buf)
3083 mutex_unlock(&lock);
3084 else
3085 kfree(local_buf);
3086
3087 return status;
3088}
3089EXPORT_SYMBOL_GPL(spi_write_then_read);
3090
3091/*-------------------------------------------------------------------------*/
3092
3093#if IS_ENABLED(CONFIG_OF_DYNAMIC)
3094static int __spi_of_device_match(struct device *dev, void *data)
3095{
3096 return dev->of_node == data;
3097}
3098
3099/* must call put_device() when done with returned spi_device device */
3100static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3101{
3102 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3103 __spi_of_device_match);
3104 return dev ? to_spi_device(dev) : NULL;
3105}
3106
3107static int __spi_of_master_match(struct device *dev, const void *data)
3108{
3109 return dev->of_node == data;
3110}
3111
3112/* the spi masters are not using spi_bus, so we find it with another way */
3113static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3114{
3115 struct device *dev;
3116
3117 dev = class_find_device(&spi_master_class, NULL, node,
3118 __spi_of_master_match);
3119 if (!dev)
3120 return NULL;
3121
3122 /* reference got in class_find_device */
3123 return container_of(dev, struct spi_master, dev);
3124}
3125
3126static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3127 void *arg)
3128{
3129 struct of_reconfig_data *rd = arg;
3130 struct spi_master *master;
3131 struct spi_device *spi;
3132
3133 switch (of_reconfig_get_state_change(action, arg)) {
3134 case OF_RECONFIG_CHANGE_ADD:
3135 master = of_find_spi_master_by_node(rd->dn->parent);
3136 if (master == NULL)
3137 return NOTIFY_OK; /* not for us */
3138
3139 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3140 put_device(&master->dev);
3141 return NOTIFY_OK;
3142 }
3143
3144 spi = of_register_spi_device(master, rd->dn);
3145 put_device(&master->dev);
3146
3147 if (IS_ERR(spi)) {
3148 pr_err("%s: failed to create for '%s'\n",
3149 __func__, rd->dn->full_name);
3150 of_node_clear_flag(rd->dn, OF_POPULATED);
3151 return notifier_from_errno(PTR_ERR(spi));
3152 }
3153 break;
3154
3155 case OF_RECONFIG_CHANGE_REMOVE:
3156 /* already depopulated? */
3157 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3158 return NOTIFY_OK;
3159
3160 /* find our device by node */
3161 spi = of_find_spi_device_by_node(rd->dn);
3162 if (spi == NULL)
3163 return NOTIFY_OK; /* no? not meant for us */
3164
3165 /* unregister takes one ref away */
3166 spi_unregister_device(spi);
3167
3168 /* and put the reference of the find */
3169 put_device(&spi->dev);
3170 break;
3171 }
3172
3173 return NOTIFY_OK;
3174}
3175
3176static struct notifier_block spi_of_notifier = {
3177 .notifier_call = of_spi_notify,
3178};
3179#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3180extern struct notifier_block spi_of_notifier;
3181#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3182
3183#if IS_ENABLED(CONFIG_ACPI)
3184static int spi_acpi_master_match(struct device *dev, const void *data)
3185{
3186 return ACPI_COMPANION(dev->parent) == data;
3187}
3188
3189static int spi_acpi_device_match(struct device *dev, void *data)
3190{
3191 return ACPI_COMPANION(dev) == data;
3192}
3193
3194static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3195{
3196 struct device *dev;
3197
3198 dev = class_find_device(&spi_master_class, NULL, adev,
3199 spi_acpi_master_match);
3200 if (!dev)
3201 return NULL;
3202
3203 return container_of(dev, struct spi_master, dev);
3204}
3205
3206static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3207{
3208 struct device *dev;
3209
3210 dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3211
3212 return dev ? to_spi_device(dev) : NULL;
3213}
3214
3215static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3216 void *arg)
3217{
3218 struct acpi_device *adev = arg;
3219 struct spi_master *master;
3220 struct spi_device *spi;
3221
3222 switch (value) {
3223 case ACPI_RECONFIG_DEVICE_ADD:
3224 master = acpi_spi_find_master_by_adev(adev->parent);
3225 if (!master)
3226 break;
3227
3228 acpi_register_spi_device(master, adev);
3229 put_device(&master->dev);
3230 break;
3231 case ACPI_RECONFIG_DEVICE_REMOVE:
3232 if (!acpi_device_enumerated(adev))
3233 break;
3234
3235 spi = acpi_spi_find_device_by_adev(adev);
3236 if (!spi)
3237 break;
3238
3239 spi_unregister_device(spi);
3240 put_device(&spi->dev);
3241 break;
3242 }
3243
3244 return NOTIFY_OK;
3245}
3246
3247static struct notifier_block spi_acpi_notifier = {
3248 .notifier_call = acpi_spi_notify,
3249};
3250#else
3251extern struct notifier_block spi_acpi_notifier;
3252#endif
3253
3254static int __init spi_init(void)
3255{
3256 int status;
3257
3258 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3259 if (!buf) {
3260 status = -ENOMEM;
3261 goto err0;
3262 }
3263
3264 status = bus_register(&spi_bus_type);
3265 if (status < 0)
3266 goto err1;
3267
3268 status = class_register(&spi_master_class);
3269 if (status < 0)
3270 goto err2;
3271
3272 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3273 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3274 if (IS_ENABLED(CONFIG_ACPI))
3275 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3276
3277 return 0;
3278
3279err2:
3280 bus_unregister(&spi_bus_type);
3281err1:
3282 kfree(buf);
3283 buf = NULL;
3284err0:
3285 return status;
3286}
3287
3288/* board_info is normally registered in arch_initcall(),
3289 * but even essential drivers wait till later
3290 *
3291 * REVISIT only boardinfo really needs static linking. the rest (device and
3292 * driver registration) _could_ be dynamically linked (modular) ... costs
3293 * include needing to have boardinfo data structures be much more public.
3294 */
3295postcore_initcall(spi_init);
3296