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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 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#include <linux/kernel.h>
23#include <linux/kmod.h>
24#include <linux/device.h>
25#include <linux/init.h>
26#include <linux/cache.h>
27#include <linux/dma-mapping.h>
28#include <linux/dmaengine.h>
29#include <linux/mutex.h>
30#include <linux/of_device.h>
31#include <linux/of_irq.h>
32#include <linux/slab.h>
33#include <linux/mod_devicetable.h>
34#include <linux/spi/spi.h>
35#include <linux/of_gpio.h>
36#include <linux/pm_runtime.h>
37#include <linux/export.h>
38#include <linux/sched/rt.h>
39#include <linux/delay.h>
40#include <linux/kthread.h>
41#include <linux/ioport.h>
42#include <linux/acpi.h>
43
44#define CREATE_TRACE_POINTS
45#include <trace/events/spi.h>
46
47static void spidev_release(struct device *dev)
48{
49 struct spi_device *spi = to_spi_device(dev);
50
51 /* spi masters may cleanup for released devices */
52 if (spi->master->cleanup)
53 spi->master->cleanup(spi);
54
55 spi_master_put(spi->master);
56 kfree(spi);
57}
58
59static ssize_t
60modalias_show(struct device *dev, struct device_attribute *a, char *buf)
61{
62 const struct spi_device *spi = to_spi_device(dev);
63 int len;
64
65 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 if (len != -ENODEV)
67 return len;
68
69 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
70}
71static DEVICE_ATTR_RO(modalias);
72
73static struct attribute *spi_dev_attrs[] = {
74 &dev_attr_modalias.attr,
75 NULL,
76};
77ATTRIBUTE_GROUPS(spi_dev);
78
79/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
80 * and the sysfs version makes coldplug work too.
81 */
82
83static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
84 const struct spi_device *sdev)
85{
86 while (id->name[0]) {
87 if (!strcmp(sdev->modalias, id->name))
88 return id;
89 id++;
90 }
91 return NULL;
92}
93
94const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
95{
96 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
97
98 return spi_match_id(sdrv->id_table, sdev);
99}
100EXPORT_SYMBOL_GPL(spi_get_device_id);
101
102static int spi_match_device(struct device *dev, struct device_driver *drv)
103{
104 const struct spi_device *spi = to_spi_device(dev);
105 const struct spi_driver *sdrv = to_spi_driver(drv);
106
107 /* Attempt an OF style match */
108 if (of_driver_match_device(dev, drv))
109 return 1;
110
111 /* Then try ACPI */
112 if (acpi_driver_match_device(dev, drv))
113 return 1;
114
115 if (sdrv->id_table)
116 return !!spi_match_id(sdrv->id_table, spi);
117
118 return strcmp(spi->modalias, drv->name) == 0;
119}
120
121static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
122{
123 const struct spi_device *spi = to_spi_device(dev);
124 int rc;
125
126 rc = acpi_device_uevent_modalias(dev, env);
127 if (rc != -ENODEV)
128 return rc;
129
130 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
131 return 0;
132}
133
134#ifdef CONFIG_PM_SLEEP
135static int spi_legacy_suspend(struct device *dev, pm_message_t message)
136{
137 int value = 0;
138 struct spi_driver *drv = to_spi_driver(dev->driver);
139
140 /* suspend will stop irqs and dma; no more i/o */
141 if (drv) {
142 if (drv->suspend)
143 value = drv->suspend(to_spi_device(dev), message);
144 else
145 dev_dbg(dev, "... can't suspend\n");
146 }
147 return value;
148}
149
150static int spi_legacy_resume(struct device *dev)
151{
152 int value = 0;
153 struct spi_driver *drv = to_spi_driver(dev->driver);
154
155 /* resume may restart the i/o queue */
156 if (drv) {
157 if (drv->resume)
158 value = drv->resume(to_spi_device(dev));
159 else
160 dev_dbg(dev, "... can't resume\n");
161 }
162 return value;
163}
164
165static int spi_pm_suspend(struct device *dev)
166{
167 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168
169 if (pm)
170 return pm_generic_suspend(dev);
171 else
172 return spi_legacy_suspend(dev, PMSG_SUSPEND);
173}
174
175static int spi_pm_resume(struct device *dev)
176{
177 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178
179 if (pm)
180 return pm_generic_resume(dev);
181 else
182 return spi_legacy_resume(dev);
183}
184
185static int spi_pm_freeze(struct device *dev)
186{
187 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188
189 if (pm)
190 return pm_generic_freeze(dev);
191 else
192 return spi_legacy_suspend(dev, PMSG_FREEZE);
193}
194
195static int spi_pm_thaw(struct device *dev)
196{
197 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198
199 if (pm)
200 return pm_generic_thaw(dev);
201 else
202 return spi_legacy_resume(dev);
203}
204
205static int spi_pm_poweroff(struct device *dev)
206{
207 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208
209 if (pm)
210 return pm_generic_poweroff(dev);
211 else
212 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
213}
214
215static int spi_pm_restore(struct device *dev)
216{
217 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
218
219 if (pm)
220 return pm_generic_restore(dev);
221 else
222 return spi_legacy_resume(dev);
223}
224#else
225#define spi_pm_suspend NULL
226#define spi_pm_resume NULL
227#define spi_pm_freeze NULL
228#define spi_pm_thaw NULL
229#define spi_pm_poweroff NULL
230#define spi_pm_restore NULL
231#endif
232
233static const struct dev_pm_ops spi_pm = {
234 .suspend = spi_pm_suspend,
235 .resume = spi_pm_resume,
236 .freeze = spi_pm_freeze,
237 .thaw = spi_pm_thaw,
238 .poweroff = spi_pm_poweroff,
239 .restore = spi_pm_restore,
240 SET_RUNTIME_PM_OPS(
241 pm_generic_runtime_suspend,
242 pm_generic_runtime_resume,
243 NULL
244 )
245};
246
247struct bus_type spi_bus_type = {
248 .name = "spi",
249 .dev_groups = spi_dev_groups,
250 .match = spi_match_device,
251 .uevent = spi_uevent,
252 .pm = &spi_pm,
253};
254EXPORT_SYMBOL_GPL(spi_bus_type);
255
256
257static int spi_drv_probe(struct device *dev)
258{
259 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
260 int ret;
261
262 acpi_dev_pm_attach(dev, true);
263 ret = sdrv->probe(to_spi_device(dev));
264 if (ret)
265 acpi_dev_pm_detach(dev, true);
266
267 return ret;
268}
269
270static int spi_drv_remove(struct device *dev)
271{
272 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
273 int ret;
274
275 ret = sdrv->remove(to_spi_device(dev));
276 acpi_dev_pm_detach(dev, true);
277
278 return ret;
279}
280
281static void spi_drv_shutdown(struct device *dev)
282{
283 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
284
285 sdrv->shutdown(to_spi_device(dev));
286}
287
288/**
289 * spi_register_driver - register a SPI driver
290 * @sdrv: the driver to register
291 * Context: can sleep
292 */
293int spi_register_driver(struct spi_driver *sdrv)
294{
295 sdrv->driver.bus = &spi_bus_type;
296 if (sdrv->probe)
297 sdrv->driver.probe = spi_drv_probe;
298 if (sdrv->remove)
299 sdrv->driver.remove = spi_drv_remove;
300 if (sdrv->shutdown)
301 sdrv->driver.shutdown = spi_drv_shutdown;
302 return driver_register(&sdrv->driver);
303}
304EXPORT_SYMBOL_GPL(spi_register_driver);
305
306/*-------------------------------------------------------------------------*/
307
308/* SPI devices should normally not be created by SPI device drivers; that
309 * would make them board-specific. Similarly with SPI master drivers.
310 * Device registration normally goes into like arch/.../mach.../board-YYY.c
311 * with other readonly (flashable) information about mainboard devices.
312 */
313
314struct boardinfo {
315 struct list_head list;
316 struct spi_board_info board_info;
317};
318
319static LIST_HEAD(board_list);
320static LIST_HEAD(spi_master_list);
321
322/*
323 * Used to protect add/del opertion for board_info list and
324 * spi_master list, and their matching process
325 */
326static DEFINE_MUTEX(board_lock);
327
328/**
329 * spi_alloc_device - Allocate a new SPI device
330 * @master: Controller to which device is connected
331 * Context: can sleep
332 *
333 * Allows a driver to allocate and initialize a spi_device without
334 * registering it immediately. This allows a driver to directly
335 * fill the spi_device with device parameters before calling
336 * spi_add_device() on it.
337 *
338 * Caller is responsible to call spi_add_device() on the returned
339 * spi_device structure to add it to the SPI master. If the caller
340 * needs to discard the spi_device without adding it, then it should
341 * call spi_dev_put() on it.
342 *
343 * Returns a pointer to the new device, or NULL.
344 */
345struct spi_device *spi_alloc_device(struct spi_master *master)
346{
347 struct spi_device *spi;
348 struct device *dev = master->dev.parent;
349
350 if (!spi_master_get(master))
351 return NULL;
352
353 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
354 if (!spi) {
355 dev_err(dev, "cannot alloc spi_device\n");
356 spi_master_put(master);
357 return NULL;
358 }
359
360 spi->master = master;
361 spi->dev.parent = &master->dev;
362 spi->dev.bus = &spi_bus_type;
363 spi->dev.release = spidev_release;
364 spi->cs_gpio = -ENOENT;
365 device_initialize(&spi->dev);
366 return spi;
367}
368EXPORT_SYMBOL_GPL(spi_alloc_device);
369
370static void spi_dev_set_name(struct spi_device *spi)
371{
372 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
373
374 if (adev) {
375 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
376 return;
377 }
378
379 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
380 spi->chip_select);
381}
382
383static int spi_dev_check(struct device *dev, void *data)
384{
385 struct spi_device *spi = to_spi_device(dev);
386 struct spi_device *new_spi = data;
387
388 if (spi->master == new_spi->master &&
389 spi->chip_select == new_spi->chip_select)
390 return -EBUSY;
391 return 0;
392}
393
394/**
395 * spi_add_device - Add spi_device allocated with spi_alloc_device
396 * @spi: spi_device to register
397 *
398 * Companion function to spi_alloc_device. Devices allocated with
399 * spi_alloc_device can be added onto the spi bus with this function.
400 *
401 * Returns 0 on success; negative errno on failure
402 */
403int spi_add_device(struct spi_device *spi)
404{
405 static DEFINE_MUTEX(spi_add_lock);
406 struct spi_master *master = spi->master;
407 struct device *dev = master->dev.parent;
408 int status;
409
410 /* Chipselects are numbered 0..max; validate. */
411 if (spi->chip_select >= master->num_chipselect) {
412 dev_err(dev, "cs%d >= max %d\n",
413 spi->chip_select,
414 master->num_chipselect);
415 return -EINVAL;
416 }
417
418 /* Set the bus ID string */
419 spi_dev_set_name(spi);
420
421 /* We need to make sure there's no other device with this
422 * chipselect **BEFORE** we call setup(), else we'll trash
423 * its configuration. Lock against concurrent add() calls.
424 */
425 mutex_lock(&spi_add_lock);
426
427 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
428 if (status) {
429 dev_err(dev, "chipselect %d already in use\n",
430 spi->chip_select);
431 goto done;
432 }
433
434 if (master->cs_gpios)
435 spi->cs_gpio = master->cs_gpios[spi->chip_select];
436
437 /* Drivers may modify this initial i/o setup, but will
438 * normally rely on the device being setup. Devices
439 * using SPI_CS_HIGH can't coexist well otherwise...
440 */
441 status = spi_setup(spi);
442 if (status < 0) {
443 dev_err(dev, "can't setup %s, status %d\n",
444 dev_name(&spi->dev), status);
445 goto done;
446 }
447
448 /* Device may be bound to an active driver when this returns */
449 status = device_add(&spi->dev);
450 if (status < 0)
451 dev_err(dev, "can't add %s, status %d\n",
452 dev_name(&spi->dev), status);
453 else
454 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
455
456done:
457 mutex_unlock(&spi_add_lock);
458 return status;
459}
460EXPORT_SYMBOL_GPL(spi_add_device);
461
462/**
463 * spi_new_device - instantiate one new SPI device
464 * @master: Controller to which device is connected
465 * @chip: Describes the SPI device
466 * Context: can sleep
467 *
468 * On typical mainboards, this is purely internal; and it's not needed
469 * after board init creates the hard-wired devices. Some development
470 * platforms may not be able to use spi_register_board_info though, and
471 * this is exported so that for example a USB or parport based adapter
472 * driver could add devices (which it would learn about out-of-band).
473 *
474 * Returns the new device, or NULL.
475 */
476struct spi_device *spi_new_device(struct spi_master *master,
477 struct spi_board_info *chip)
478{
479 struct spi_device *proxy;
480 int status;
481
482 /* NOTE: caller did any chip->bus_num checks necessary.
483 *
484 * Also, unless we change the return value convention to use
485 * error-or-pointer (not NULL-or-pointer), troubleshootability
486 * suggests syslogged diagnostics are best here (ugh).
487 */
488
489 proxy = spi_alloc_device(master);
490 if (!proxy)
491 return NULL;
492
493 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
494
495 proxy->chip_select = chip->chip_select;
496 proxy->max_speed_hz = chip->max_speed_hz;
497 proxy->mode = chip->mode;
498 proxy->irq = chip->irq;
499 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
500 proxy->dev.platform_data = (void *) chip->platform_data;
501 proxy->controller_data = chip->controller_data;
502 proxy->controller_state = NULL;
503
504 status = spi_add_device(proxy);
505 if (status < 0) {
506 spi_dev_put(proxy);
507 return NULL;
508 }
509
510 return proxy;
511}
512EXPORT_SYMBOL_GPL(spi_new_device);
513
514static void spi_match_master_to_boardinfo(struct spi_master *master,
515 struct spi_board_info *bi)
516{
517 struct spi_device *dev;
518
519 if (master->bus_num != bi->bus_num)
520 return;
521
522 dev = spi_new_device(master, bi);
523 if (!dev)
524 dev_err(master->dev.parent, "can't create new device for %s\n",
525 bi->modalias);
526}
527
528/**
529 * spi_register_board_info - register SPI devices for a given board
530 * @info: array of chip descriptors
531 * @n: how many descriptors are provided
532 * Context: can sleep
533 *
534 * Board-specific early init code calls this (probably during arch_initcall)
535 * with segments of the SPI device table. Any device nodes are created later,
536 * after the relevant parent SPI controller (bus_num) is defined. We keep
537 * this table of devices forever, so that reloading a controller driver will
538 * not make Linux forget about these hard-wired devices.
539 *
540 * Other code can also call this, e.g. a particular add-on board might provide
541 * SPI devices through its expansion connector, so code initializing that board
542 * would naturally declare its SPI devices.
543 *
544 * The board info passed can safely be __initdata ... but be careful of
545 * any embedded pointers (platform_data, etc), they're copied as-is.
546 */
547int spi_register_board_info(struct spi_board_info const *info, unsigned n)
548{
549 struct boardinfo *bi;
550 int i;
551
552 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
553 if (!bi)
554 return -ENOMEM;
555
556 for (i = 0; i < n; i++, bi++, info++) {
557 struct spi_master *master;
558
559 memcpy(&bi->board_info, info, sizeof(*info));
560 mutex_lock(&board_lock);
561 list_add_tail(&bi->list, &board_list);
562 list_for_each_entry(master, &spi_master_list, list)
563 spi_match_master_to_boardinfo(master, &bi->board_info);
564 mutex_unlock(&board_lock);
565 }
566
567 return 0;
568}
569
570/*-------------------------------------------------------------------------*/
571
572static void spi_set_cs(struct spi_device *spi, bool enable)
573{
574 if (spi->mode & SPI_CS_HIGH)
575 enable = !enable;
576
577 if (spi->cs_gpio >= 0)
578 gpio_set_value(spi->cs_gpio, !enable);
579 else if (spi->master->set_cs)
580 spi->master->set_cs(spi, !enable);
581}
582
583#ifdef CONFIG_HAS_DMA
584static int spi_map_buf(struct spi_master *master, struct device *dev,
585 struct sg_table *sgt, void *buf, size_t len,
586 enum dma_data_direction dir)
587{
588 const bool vmalloced_buf = is_vmalloc_addr(buf);
589 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
590 const int sgs = DIV_ROUND_UP(len, desc_len);
591 struct page *vm_page;
592 void *sg_buf;
593 size_t min;
594 int i, ret;
595
596 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
597 if (ret != 0)
598 return ret;
599
600 for (i = 0; i < sgs; i++) {
601 min = min_t(size_t, len, desc_len);
602
603 if (vmalloced_buf) {
604 vm_page = vmalloc_to_page(buf);
605 if (!vm_page) {
606 sg_free_table(sgt);
607 return -ENOMEM;
608 }
609 sg_buf = page_address(vm_page) +
610 ((size_t)buf & ~PAGE_MASK);
611 } else {
612 sg_buf = buf;
613 }
614
615 sg_set_buf(&sgt->sgl[i], sg_buf, min);
616
617 buf += min;
618 len -= min;
619 }
620
621 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
622 if (ret < 0) {
623 sg_free_table(sgt);
624 return ret;
625 }
626
627 sgt->nents = ret;
628
629 return 0;
630}
631
632static void spi_unmap_buf(struct spi_master *master, struct device *dev,
633 struct sg_table *sgt, enum dma_data_direction dir)
634{
635 if (sgt->orig_nents) {
636 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
637 sg_free_table(sgt);
638 }
639}
640
641static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
642{
643 struct device *tx_dev, *rx_dev;
644 struct spi_transfer *xfer;
645 int ret;
646
647 if (!master->can_dma)
648 return 0;
649
650 tx_dev = &master->dma_tx->dev->device;
651 rx_dev = &master->dma_rx->dev->device;
652
653 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
654 if (!master->can_dma(master, msg->spi, xfer))
655 continue;
656
657 if (xfer->tx_buf != NULL) {
658 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
659 (void *)xfer->tx_buf, xfer->len,
660 DMA_TO_DEVICE);
661 if (ret != 0)
662 return ret;
663 }
664
665 if (xfer->rx_buf != NULL) {
666 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
667 xfer->rx_buf, xfer->len,
668 DMA_FROM_DEVICE);
669 if (ret != 0) {
670 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
671 DMA_TO_DEVICE);
672 return ret;
673 }
674 }
675 }
676
677 master->cur_msg_mapped = true;
678
679 return 0;
680}
681
682static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
683{
684 struct spi_transfer *xfer;
685 struct device *tx_dev, *rx_dev;
686
687 if (!master->cur_msg_mapped || !master->can_dma)
688 return 0;
689
690 tx_dev = &master->dma_tx->dev->device;
691 rx_dev = &master->dma_rx->dev->device;
692
693 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
694 if (!master->can_dma(master, msg->spi, xfer))
695 continue;
696
697 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
698 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
699 }
700
701 return 0;
702}
703#else /* !CONFIG_HAS_DMA */
704static inline int __spi_map_msg(struct spi_master *master,
705 struct spi_message *msg)
706{
707 return 0;
708}
709
710static inline int spi_unmap_msg(struct spi_master *master,
711 struct spi_message *msg)
712{
713 return 0;
714}
715#endif /* !CONFIG_HAS_DMA */
716
717static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
718{
719 struct spi_transfer *xfer;
720 void *tmp;
721 unsigned int max_tx, max_rx;
722
723 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
724 max_tx = 0;
725 max_rx = 0;
726
727 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
728 if ((master->flags & SPI_MASTER_MUST_TX) &&
729 !xfer->tx_buf)
730 max_tx = max(xfer->len, max_tx);
731 if ((master->flags & SPI_MASTER_MUST_RX) &&
732 !xfer->rx_buf)
733 max_rx = max(xfer->len, max_rx);
734 }
735
736 if (max_tx) {
737 tmp = krealloc(master->dummy_tx, max_tx,
738 GFP_KERNEL | GFP_DMA);
739 if (!tmp)
740 return -ENOMEM;
741 master->dummy_tx = tmp;
742 memset(tmp, 0, max_tx);
743 }
744
745 if (max_rx) {
746 tmp = krealloc(master->dummy_rx, max_rx,
747 GFP_KERNEL | GFP_DMA);
748 if (!tmp)
749 return -ENOMEM;
750 master->dummy_rx = tmp;
751 }
752
753 if (max_tx || max_rx) {
754 list_for_each_entry(xfer, &msg->transfers,
755 transfer_list) {
756 if (!xfer->tx_buf)
757 xfer->tx_buf = master->dummy_tx;
758 if (!xfer->rx_buf)
759 xfer->rx_buf = master->dummy_rx;
760 }
761 }
762 }
763
764 return __spi_map_msg(master, msg);
765}
766
767/*
768 * spi_transfer_one_message - Default implementation of transfer_one_message()
769 *
770 * This is a standard implementation of transfer_one_message() for
771 * drivers which impelment a transfer_one() operation. It provides
772 * standard handling of delays and chip select management.
773 */
774static int spi_transfer_one_message(struct spi_master *master,
775 struct spi_message *msg)
776{
777 struct spi_transfer *xfer;
778 bool keep_cs = false;
779 int ret = 0;
780 int ms = 1;
781
782 spi_set_cs(msg->spi, true);
783
784 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
785 trace_spi_transfer_start(msg, xfer);
786
787 reinit_completion(&master->xfer_completion);
788
789 ret = master->transfer_one(master, msg->spi, xfer);
790 if (ret < 0) {
791 dev_err(&msg->spi->dev,
792 "SPI transfer failed: %d\n", ret);
793 goto out;
794 }
795
796 if (ret > 0) {
797 ret = 0;
798 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
799 ms += 10; /* some tolerance */
800
801 ms = wait_for_completion_timeout(&master->xfer_completion,
802 msecs_to_jiffies(ms));
803 }
804
805 if (ms == 0) {
806 dev_err(&msg->spi->dev, "SPI transfer timed out\n");
807 msg->status = -ETIMEDOUT;
808 }
809
810 trace_spi_transfer_stop(msg, xfer);
811
812 if (msg->status != -EINPROGRESS)
813 goto out;
814
815 if (xfer->delay_usecs)
816 udelay(xfer->delay_usecs);
817
818 if (xfer->cs_change) {
819 if (list_is_last(&xfer->transfer_list,
820 &msg->transfers)) {
821 keep_cs = true;
822 } else {
823 spi_set_cs(msg->spi, false);
824 udelay(10);
825 spi_set_cs(msg->spi, true);
826 }
827 }
828
829 msg->actual_length += xfer->len;
830 }
831
832out:
833 if (ret != 0 || !keep_cs)
834 spi_set_cs(msg->spi, false);
835
836 if (msg->status == -EINPROGRESS)
837 msg->status = ret;
838
839 spi_finalize_current_message(master);
840
841 return ret;
842}
843
844/**
845 * spi_finalize_current_transfer - report completion of a transfer
846 *
847 * Called by SPI drivers using the core transfer_one_message()
848 * implementation to notify it that the current interrupt driven
849 * transfer has finished and the next one may be scheduled.
850 */
851void spi_finalize_current_transfer(struct spi_master *master)
852{
853 complete(&master->xfer_completion);
854}
855EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
856
857/**
858 * spi_pump_messages - kthread work function which processes spi message queue
859 * @work: pointer to kthread work struct contained in the master struct
860 *
861 * This function checks if there is any spi message in the queue that
862 * needs processing and if so call out to the driver to initialize hardware
863 * and transfer each message.
864 *
865 */
866static void spi_pump_messages(struct kthread_work *work)
867{
868 struct spi_master *master =
869 container_of(work, struct spi_master, pump_messages);
870 unsigned long flags;
871 bool was_busy = false;
872 int ret;
873
874 /* Lock queue and check for queue work */
875 spin_lock_irqsave(&master->queue_lock, flags);
876 if (list_empty(&master->queue) || !master->running) {
877 if (!master->busy) {
878 spin_unlock_irqrestore(&master->queue_lock, flags);
879 return;
880 }
881 master->busy = false;
882 spin_unlock_irqrestore(&master->queue_lock, flags);
883 kfree(master->dummy_rx);
884 master->dummy_rx = NULL;
885 kfree(master->dummy_tx);
886 master->dummy_tx = NULL;
887 if (master->unprepare_transfer_hardware &&
888 master->unprepare_transfer_hardware(master))
889 dev_err(&master->dev,
890 "failed to unprepare transfer hardware\n");
891 if (master->auto_runtime_pm) {
892 pm_runtime_mark_last_busy(master->dev.parent);
893 pm_runtime_put_autosuspend(master->dev.parent);
894 }
895 trace_spi_master_idle(master);
896 return;
897 }
898
899 /* Make sure we are not already running a message */
900 if (master->cur_msg) {
901 spin_unlock_irqrestore(&master->queue_lock, flags);
902 return;
903 }
904 /* Extract head of queue */
905 master->cur_msg =
906 list_first_entry(&master->queue, struct spi_message, queue);
907
908 list_del_init(&master->cur_msg->queue);
909 if (master->busy)
910 was_busy = true;
911 else
912 master->busy = true;
913 spin_unlock_irqrestore(&master->queue_lock, flags);
914
915 if (!was_busy && master->auto_runtime_pm) {
916 ret = pm_runtime_get_sync(master->dev.parent);
917 if (ret < 0) {
918 dev_err(&master->dev, "Failed to power device: %d\n",
919 ret);
920 return;
921 }
922 }
923
924 if (!was_busy)
925 trace_spi_master_busy(master);
926
927 if (!was_busy && master->prepare_transfer_hardware) {
928 ret = master->prepare_transfer_hardware(master);
929 if (ret) {
930 dev_err(&master->dev,
931 "failed to prepare transfer hardware\n");
932
933 if (master->auto_runtime_pm)
934 pm_runtime_put(master->dev.parent);
935 return;
936 }
937 }
938
939 trace_spi_message_start(master->cur_msg);
940
941 if (master->prepare_message) {
942 ret = master->prepare_message(master, master->cur_msg);
943 if (ret) {
944 dev_err(&master->dev,
945 "failed to prepare message: %d\n", ret);
946 master->cur_msg->status = ret;
947 spi_finalize_current_message(master);
948 return;
949 }
950 master->cur_msg_prepared = true;
951 }
952
953 ret = spi_map_msg(master, master->cur_msg);
954 if (ret) {
955 master->cur_msg->status = ret;
956 spi_finalize_current_message(master);
957 return;
958 }
959
960 ret = master->transfer_one_message(master, master->cur_msg);
961 if (ret) {
962 dev_err(&master->dev,
963 "failed to transfer one message from queue\n");
964 return;
965 }
966}
967
968static int spi_init_queue(struct spi_master *master)
969{
970 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
971
972 INIT_LIST_HEAD(&master->queue);
973 spin_lock_init(&master->queue_lock);
974
975 master->running = false;
976 master->busy = false;
977
978 init_kthread_worker(&master->kworker);
979 master->kworker_task = kthread_run(kthread_worker_fn,
980 &master->kworker, "%s",
981 dev_name(&master->dev));
982 if (IS_ERR(master->kworker_task)) {
983 dev_err(&master->dev, "failed to create message pump task\n");
984 return -ENOMEM;
985 }
986 init_kthread_work(&master->pump_messages, spi_pump_messages);
987
988 /*
989 * Master config will indicate if this controller should run the
990 * message pump with high (realtime) priority to reduce the transfer
991 * latency on the bus by minimising the delay between a transfer
992 * request and the scheduling of the message pump thread. Without this
993 * setting the message pump thread will remain at default priority.
994 */
995 if (master->rt) {
996 dev_info(&master->dev,
997 "will run message pump with realtime priority\n");
998 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
999 }
1000
1001 return 0;
1002}
1003
1004/**
1005 * spi_get_next_queued_message() - called by driver to check for queued
1006 * messages
1007 * @master: the master to check for queued messages
1008 *
1009 * If there are more messages in the queue, the next message is returned from
1010 * this call.
1011 */
1012struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1013{
1014 struct spi_message *next;
1015 unsigned long flags;
1016
1017 /* get a pointer to the next message, if any */
1018 spin_lock_irqsave(&master->queue_lock, flags);
1019 next = list_first_entry_or_null(&master->queue, struct spi_message,
1020 queue);
1021 spin_unlock_irqrestore(&master->queue_lock, flags);
1022
1023 return next;
1024}
1025EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1026
1027/**
1028 * spi_finalize_current_message() - the current message is complete
1029 * @master: the master to return the message to
1030 *
1031 * Called by the driver to notify the core that the message in the front of the
1032 * queue is complete and can be removed from the queue.
1033 */
1034void spi_finalize_current_message(struct spi_master *master)
1035{
1036 struct spi_message *mesg;
1037 unsigned long flags;
1038 int ret;
1039
1040 spin_lock_irqsave(&master->queue_lock, flags);
1041 mesg = master->cur_msg;
1042 master->cur_msg = NULL;
1043
1044 queue_kthread_work(&master->kworker, &master->pump_messages);
1045 spin_unlock_irqrestore(&master->queue_lock, flags);
1046
1047 spi_unmap_msg(master, mesg);
1048
1049 if (master->cur_msg_prepared && master->unprepare_message) {
1050 ret = master->unprepare_message(master, mesg);
1051 if (ret) {
1052 dev_err(&master->dev,
1053 "failed to unprepare message: %d\n", ret);
1054 }
1055 }
1056 master->cur_msg_prepared = false;
1057
1058 mesg->state = NULL;
1059 if (mesg->complete)
1060 mesg->complete(mesg->context);
1061
1062 trace_spi_message_done(mesg);
1063}
1064EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1065
1066static int spi_start_queue(struct spi_master *master)
1067{
1068 unsigned long flags;
1069
1070 spin_lock_irqsave(&master->queue_lock, flags);
1071
1072 if (master->running || master->busy) {
1073 spin_unlock_irqrestore(&master->queue_lock, flags);
1074 return -EBUSY;
1075 }
1076
1077 master->running = true;
1078 master->cur_msg = NULL;
1079 spin_unlock_irqrestore(&master->queue_lock, flags);
1080
1081 queue_kthread_work(&master->kworker, &master->pump_messages);
1082
1083 return 0;
1084}
1085
1086static int spi_stop_queue(struct spi_master *master)
1087{
1088 unsigned long flags;
1089 unsigned limit = 500;
1090 int ret = 0;
1091
1092 spin_lock_irqsave(&master->queue_lock, flags);
1093
1094 /*
1095 * This is a bit lame, but is optimized for the common execution path.
1096 * A wait_queue on the master->busy could be used, but then the common
1097 * execution path (pump_messages) would be required to call wake_up or
1098 * friends on every SPI message. Do this instead.
1099 */
1100 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1101 spin_unlock_irqrestore(&master->queue_lock, flags);
1102 usleep_range(10000, 11000);
1103 spin_lock_irqsave(&master->queue_lock, flags);
1104 }
1105
1106 if (!list_empty(&master->queue) || master->busy)
1107 ret = -EBUSY;
1108 else
1109 master->running = false;
1110
1111 spin_unlock_irqrestore(&master->queue_lock, flags);
1112
1113 if (ret) {
1114 dev_warn(&master->dev,
1115 "could not stop message queue\n");
1116 return ret;
1117 }
1118 return ret;
1119}
1120
1121static int spi_destroy_queue(struct spi_master *master)
1122{
1123 int ret;
1124
1125 ret = spi_stop_queue(master);
1126
1127 /*
1128 * flush_kthread_worker will block until all work is done.
1129 * If the reason that stop_queue timed out is that the work will never
1130 * finish, then it does no good to call flush/stop thread, so
1131 * return anyway.
1132 */
1133 if (ret) {
1134 dev_err(&master->dev, "problem destroying queue\n");
1135 return ret;
1136 }
1137
1138 flush_kthread_worker(&master->kworker);
1139 kthread_stop(master->kworker_task);
1140
1141 return 0;
1142}
1143
1144/**
1145 * spi_queued_transfer - transfer function for queued transfers
1146 * @spi: spi device which is requesting transfer
1147 * @msg: spi message which is to handled is queued to driver queue
1148 */
1149static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1150{
1151 struct spi_master *master = spi->master;
1152 unsigned long flags;
1153
1154 spin_lock_irqsave(&master->queue_lock, flags);
1155
1156 if (!master->running) {
1157 spin_unlock_irqrestore(&master->queue_lock, flags);
1158 return -ESHUTDOWN;
1159 }
1160 msg->actual_length = 0;
1161 msg->status = -EINPROGRESS;
1162
1163 list_add_tail(&msg->queue, &master->queue);
1164 if (!master->busy)
1165 queue_kthread_work(&master->kworker, &master->pump_messages);
1166
1167 spin_unlock_irqrestore(&master->queue_lock, flags);
1168 return 0;
1169}
1170
1171static int spi_master_initialize_queue(struct spi_master *master)
1172{
1173 int ret;
1174
1175 master->transfer = spi_queued_transfer;
1176 if (!master->transfer_one_message)
1177 master->transfer_one_message = spi_transfer_one_message;
1178
1179 /* Initialize and start queue */
1180 ret = spi_init_queue(master);
1181 if (ret) {
1182 dev_err(&master->dev, "problem initializing queue\n");
1183 goto err_init_queue;
1184 }
1185 master->queued = true;
1186 ret = spi_start_queue(master);
1187 if (ret) {
1188 dev_err(&master->dev, "problem starting queue\n");
1189 goto err_start_queue;
1190 }
1191
1192 return 0;
1193
1194err_start_queue:
1195 spi_destroy_queue(master);
1196err_init_queue:
1197 return ret;
1198}
1199
1200/*-------------------------------------------------------------------------*/
1201
1202#if defined(CONFIG_OF)
1203/**
1204 * of_register_spi_devices() - Register child devices onto the SPI bus
1205 * @master: Pointer to spi_master device
1206 *
1207 * Registers an spi_device for each child node of master node which has a 'reg'
1208 * property.
1209 */
1210static void of_register_spi_devices(struct spi_master *master)
1211{
1212 struct spi_device *spi;
1213 struct device_node *nc;
1214 int rc;
1215 u32 value;
1216
1217 if (!master->dev.of_node)
1218 return;
1219
1220 for_each_available_child_of_node(master->dev.of_node, nc) {
1221 /* Alloc an spi_device */
1222 spi = spi_alloc_device(master);
1223 if (!spi) {
1224 dev_err(&master->dev, "spi_device alloc error for %s\n",
1225 nc->full_name);
1226 spi_dev_put(spi);
1227 continue;
1228 }
1229
1230 /* Select device driver */
1231 if (of_modalias_node(nc, spi->modalias,
1232 sizeof(spi->modalias)) < 0) {
1233 dev_err(&master->dev, "cannot find modalias for %s\n",
1234 nc->full_name);
1235 spi_dev_put(spi);
1236 continue;
1237 }
1238
1239 /* Device address */
1240 rc = of_property_read_u32(nc, "reg", &value);
1241 if (rc) {
1242 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1243 nc->full_name, rc);
1244 spi_dev_put(spi);
1245 continue;
1246 }
1247 spi->chip_select = value;
1248
1249 /* Mode (clock phase/polarity/etc.) */
1250 if (of_find_property(nc, "spi-cpha", NULL))
1251 spi->mode |= SPI_CPHA;
1252 if (of_find_property(nc, "spi-cpol", NULL))
1253 spi->mode |= SPI_CPOL;
1254 if (of_find_property(nc, "spi-cs-high", NULL))
1255 spi->mode |= SPI_CS_HIGH;
1256 if (of_find_property(nc, "spi-3wire", NULL))
1257 spi->mode |= SPI_3WIRE;
1258
1259 /* Device DUAL/QUAD mode */
1260 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1261 switch (value) {
1262 case 1:
1263 break;
1264 case 2:
1265 spi->mode |= SPI_TX_DUAL;
1266 break;
1267 case 4:
1268 spi->mode |= SPI_TX_QUAD;
1269 break;
1270 default:
1271 dev_err(&master->dev,
1272 "spi-tx-bus-width %d not supported\n",
1273 value);
1274 spi_dev_put(spi);
1275 continue;
1276 }
1277 }
1278
1279 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1280 switch (value) {
1281 case 1:
1282 break;
1283 case 2:
1284 spi->mode |= SPI_RX_DUAL;
1285 break;
1286 case 4:
1287 spi->mode |= SPI_RX_QUAD;
1288 break;
1289 default:
1290 dev_err(&master->dev,
1291 "spi-rx-bus-width %d not supported\n",
1292 value);
1293 spi_dev_put(spi);
1294 continue;
1295 }
1296 }
1297
1298 /* Device speed */
1299 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1300 if (rc) {
1301 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1302 nc->full_name, rc);
1303 spi_dev_put(spi);
1304 continue;
1305 }
1306 spi->max_speed_hz = value;
1307
1308 /* IRQ */
1309 spi->irq = irq_of_parse_and_map(nc, 0);
1310
1311 /* Store a pointer to the node in the device structure */
1312 of_node_get(nc);
1313 spi->dev.of_node = nc;
1314
1315 /* Register the new device */
1316 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1317 rc = spi_add_device(spi);
1318 if (rc) {
1319 dev_err(&master->dev, "spi_device register error %s\n",
1320 nc->full_name);
1321 spi_dev_put(spi);
1322 }
1323
1324 }
1325}
1326#else
1327static void of_register_spi_devices(struct spi_master *master) { }
1328#endif
1329
1330#ifdef CONFIG_ACPI
1331static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1332{
1333 struct spi_device *spi = data;
1334
1335 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1336 struct acpi_resource_spi_serialbus *sb;
1337
1338 sb = &ares->data.spi_serial_bus;
1339 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1340 spi->chip_select = sb->device_selection;
1341 spi->max_speed_hz = sb->connection_speed;
1342
1343 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1344 spi->mode |= SPI_CPHA;
1345 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1346 spi->mode |= SPI_CPOL;
1347 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1348 spi->mode |= SPI_CS_HIGH;
1349 }
1350 } else if (spi->irq < 0) {
1351 struct resource r;
1352
1353 if (acpi_dev_resource_interrupt(ares, 0, &r))
1354 spi->irq = r.start;
1355 }
1356
1357 /* Always tell the ACPI core to skip this resource */
1358 return 1;
1359}
1360
1361static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1362 void *data, void **return_value)
1363{
1364 struct spi_master *master = data;
1365 struct list_head resource_list;
1366 struct acpi_device *adev;
1367 struct spi_device *spi;
1368 int ret;
1369
1370 if (acpi_bus_get_device(handle, &adev))
1371 return AE_OK;
1372 if (acpi_bus_get_status(adev) || !adev->status.present)
1373 return AE_OK;
1374
1375 spi = spi_alloc_device(master);
1376 if (!spi) {
1377 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1378 dev_name(&adev->dev));
1379 return AE_NO_MEMORY;
1380 }
1381
1382 ACPI_COMPANION_SET(&spi->dev, adev);
1383 spi->irq = -1;
1384
1385 INIT_LIST_HEAD(&resource_list);
1386 ret = acpi_dev_get_resources(adev, &resource_list,
1387 acpi_spi_add_resource, spi);
1388 acpi_dev_free_resource_list(&resource_list);
1389
1390 if (ret < 0 || !spi->max_speed_hz) {
1391 spi_dev_put(spi);
1392 return AE_OK;
1393 }
1394
1395 adev->power.flags.ignore_parent = true;
1396 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1397 if (spi_add_device(spi)) {
1398 adev->power.flags.ignore_parent = false;
1399 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1400 dev_name(&adev->dev));
1401 spi_dev_put(spi);
1402 }
1403
1404 return AE_OK;
1405}
1406
1407static void acpi_register_spi_devices(struct spi_master *master)
1408{
1409 acpi_status status;
1410 acpi_handle handle;
1411
1412 handle = ACPI_HANDLE(master->dev.parent);
1413 if (!handle)
1414 return;
1415
1416 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1417 acpi_spi_add_device, NULL,
1418 master, NULL);
1419 if (ACPI_FAILURE(status))
1420 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1421}
1422#else
1423static inline void acpi_register_spi_devices(struct spi_master *master) {}
1424#endif /* CONFIG_ACPI */
1425
1426static void spi_master_release(struct device *dev)
1427{
1428 struct spi_master *master;
1429
1430 master = container_of(dev, struct spi_master, dev);
1431 kfree(master);
1432}
1433
1434static struct class spi_master_class = {
1435 .name = "spi_master",
1436 .owner = THIS_MODULE,
1437 .dev_release = spi_master_release,
1438};
1439
1440
1441
1442/**
1443 * spi_alloc_master - allocate SPI master controller
1444 * @dev: the controller, possibly using the platform_bus
1445 * @size: how much zeroed driver-private data to allocate; the pointer to this
1446 * memory is in the driver_data field of the returned device,
1447 * accessible with spi_master_get_devdata().
1448 * Context: can sleep
1449 *
1450 * This call is used only by SPI master controller drivers, which are the
1451 * only ones directly touching chip registers. It's how they allocate
1452 * an spi_master structure, prior to calling spi_register_master().
1453 *
1454 * This must be called from context that can sleep. It returns the SPI
1455 * master structure on success, else NULL.
1456 *
1457 * The caller is responsible for assigning the bus number and initializing
1458 * the master's methods before calling spi_register_master(); and (after errors
1459 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1460 * leak.
1461 */
1462struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1463{
1464 struct spi_master *master;
1465
1466 if (!dev)
1467 return NULL;
1468
1469 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1470 if (!master)
1471 return NULL;
1472
1473 device_initialize(&master->dev);
1474 master->bus_num = -1;
1475 master->num_chipselect = 1;
1476 master->dev.class = &spi_master_class;
1477 master->dev.parent = get_device(dev);
1478 spi_master_set_devdata(master, &master[1]);
1479
1480 return master;
1481}
1482EXPORT_SYMBOL_GPL(spi_alloc_master);
1483
1484#ifdef CONFIG_OF
1485static int of_spi_register_master(struct spi_master *master)
1486{
1487 int nb, i, *cs;
1488 struct device_node *np = master->dev.of_node;
1489
1490 if (!np)
1491 return 0;
1492
1493 nb = of_gpio_named_count(np, "cs-gpios");
1494 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1495
1496 /* Return error only for an incorrectly formed cs-gpios property */
1497 if (nb == 0 || nb == -ENOENT)
1498 return 0;
1499 else if (nb < 0)
1500 return nb;
1501
1502 cs = devm_kzalloc(&master->dev,
1503 sizeof(int) * master->num_chipselect,
1504 GFP_KERNEL);
1505 master->cs_gpios = cs;
1506
1507 if (!master->cs_gpios)
1508 return -ENOMEM;
1509
1510 for (i = 0; i < master->num_chipselect; i++)
1511 cs[i] = -ENOENT;
1512
1513 for (i = 0; i < nb; i++)
1514 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1515
1516 return 0;
1517}
1518#else
1519static int of_spi_register_master(struct spi_master *master)
1520{
1521 return 0;
1522}
1523#endif
1524
1525/**
1526 * spi_register_master - register SPI master controller
1527 * @master: initialized master, originally from spi_alloc_master()
1528 * Context: can sleep
1529 *
1530 * SPI master controllers connect to their drivers using some non-SPI bus,
1531 * such as the platform bus. The final stage of probe() in that code
1532 * includes calling spi_register_master() to hook up to this SPI bus glue.
1533 *
1534 * SPI controllers use board specific (often SOC specific) bus numbers,
1535 * and board-specific addressing for SPI devices combines those numbers
1536 * with chip select numbers. Since SPI does not directly support dynamic
1537 * device identification, boards need configuration tables telling which
1538 * chip is at which address.
1539 *
1540 * This must be called from context that can sleep. It returns zero on
1541 * success, else a negative error code (dropping the master's refcount).
1542 * After a successful return, the caller is responsible for calling
1543 * spi_unregister_master().
1544 */
1545int spi_register_master(struct spi_master *master)
1546{
1547 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1548 struct device *dev = master->dev.parent;
1549 struct boardinfo *bi;
1550 int status = -ENODEV;
1551 int dynamic = 0;
1552
1553 if (!dev)
1554 return -ENODEV;
1555
1556 status = of_spi_register_master(master);
1557 if (status)
1558 return status;
1559
1560 /* even if it's just one always-selected device, there must
1561 * be at least one chipselect
1562 */
1563 if (master->num_chipselect == 0)
1564 return -EINVAL;
1565
1566 if ((master->bus_num < 0) && master->dev.of_node)
1567 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1568
1569 /* convention: dynamically assigned bus IDs count down from the max */
1570 if (master->bus_num < 0) {
1571 /* FIXME switch to an IDR based scheme, something like
1572 * I2C now uses, so we can't run out of "dynamic" IDs
1573 */
1574 master->bus_num = atomic_dec_return(&dyn_bus_id);
1575 dynamic = 1;
1576 }
1577
1578 spin_lock_init(&master->bus_lock_spinlock);
1579 mutex_init(&master->bus_lock_mutex);
1580 master->bus_lock_flag = 0;
1581 init_completion(&master->xfer_completion);
1582 if (!master->max_dma_len)
1583 master->max_dma_len = INT_MAX;
1584
1585 /* register the device, then userspace will see it.
1586 * registration fails if the bus ID is in use.
1587 */
1588 dev_set_name(&master->dev, "spi%u", master->bus_num);
1589 status = device_add(&master->dev);
1590 if (status < 0)
1591 goto done;
1592 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1593 dynamic ? " (dynamic)" : "");
1594
1595 /* If we're using a queued driver, start the queue */
1596 if (master->transfer)
1597 dev_info(dev, "master is unqueued, this is deprecated\n");
1598 else {
1599 status = spi_master_initialize_queue(master);
1600 if (status) {
1601 device_del(&master->dev);
1602 goto done;
1603 }
1604 }
1605
1606 mutex_lock(&board_lock);
1607 list_add_tail(&master->list, &spi_master_list);
1608 list_for_each_entry(bi, &board_list, list)
1609 spi_match_master_to_boardinfo(master, &bi->board_info);
1610 mutex_unlock(&board_lock);
1611
1612 /* Register devices from the device tree and ACPI */
1613 of_register_spi_devices(master);
1614 acpi_register_spi_devices(master);
1615done:
1616 return status;
1617}
1618EXPORT_SYMBOL_GPL(spi_register_master);
1619
1620static void devm_spi_unregister(struct device *dev, void *res)
1621{
1622 spi_unregister_master(*(struct spi_master **)res);
1623}
1624
1625/**
1626 * dev_spi_register_master - register managed SPI master controller
1627 * @dev: device managing SPI master
1628 * @master: initialized master, originally from spi_alloc_master()
1629 * Context: can sleep
1630 *
1631 * Register a SPI device as with spi_register_master() which will
1632 * automatically be unregister
1633 */
1634int devm_spi_register_master(struct device *dev, struct spi_master *master)
1635{
1636 struct spi_master **ptr;
1637 int ret;
1638
1639 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1640 if (!ptr)
1641 return -ENOMEM;
1642
1643 ret = spi_register_master(master);
1644 if (!ret) {
1645 *ptr = master;
1646 devres_add(dev, ptr);
1647 } else {
1648 devres_free(ptr);
1649 }
1650
1651 return ret;
1652}
1653EXPORT_SYMBOL_GPL(devm_spi_register_master);
1654
1655static int __unregister(struct device *dev, void *null)
1656{
1657 spi_unregister_device(to_spi_device(dev));
1658 return 0;
1659}
1660
1661/**
1662 * spi_unregister_master - unregister SPI master controller
1663 * @master: the master being unregistered
1664 * Context: can sleep
1665 *
1666 * This call is used only by SPI master controller drivers, which are the
1667 * only ones directly touching chip registers.
1668 *
1669 * This must be called from context that can sleep.
1670 */
1671void spi_unregister_master(struct spi_master *master)
1672{
1673 int dummy;
1674
1675 if (master->queued) {
1676 if (spi_destroy_queue(master))
1677 dev_err(&master->dev, "queue remove failed\n");
1678 }
1679
1680 mutex_lock(&board_lock);
1681 list_del(&master->list);
1682 mutex_unlock(&board_lock);
1683
1684 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1685 device_unregister(&master->dev);
1686}
1687EXPORT_SYMBOL_GPL(spi_unregister_master);
1688
1689int spi_master_suspend(struct spi_master *master)
1690{
1691 int ret;
1692
1693 /* Basically no-ops for non-queued masters */
1694 if (!master->queued)
1695 return 0;
1696
1697 ret = spi_stop_queue(master);
1698 if (ret)
1699 dev_err(&master->dev, "queue stop failed\n");
1700
1701 return ret;
1702}
1703EXPORT_SYMBOL_GPL(spi_master_suspend);
1704
1705int spi_master_resume(struct spi_master *master)
1706{
1707 int ret;
1708
1709 if (!master->queued)
1710 return 0;
1711
1712 ret = spi_start_queue(master);
1713 if (ret)
1714 dev_err(&master->dev, "queue restart failed\n");
1715
1716 return ret;
1717}
1718EXPORT_SYMBOL_GPL(spi_master_resume);
1719
1720static int __spi_master_match(struct device *dev, const void *data)
1721{
1722 struct spi_master *m;
1723 const u16 *bus_num = data;
1724
1725 m = container_of(dev, struct spi_master, dev);
1726 return m->bus_num == *bus_num;
1727}
1728
1729/**
1730 * spi_busnum_to_master - look up master associated with bus_num
1731 * @bus_num: the master's bus number
1732 * Context: can sleep
1733 *
1734 * This call may be used with devices that are registered after
1735 * arch init time. It returns a refcounted pointer to the relevant
1736 * spi_master (which the caller must release), or NULL if there is
1737 * no such master registered.
1738 */
1739struct spi_master *spi_busnum_to_master(u16 bus_num)
1740{
1741 struct device *dev;
1742 struct spi_master *master = NULL;
1743
1744 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1745 __spi_master_match);
1746 if (dev)
1747 master = container_of(dev, struct spi_master, dev);
1748 /* reference got in class_find_device */
1749 return master;
1750}
1751EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1752
1753
1754/*-------------------------------------------------------------------------*/
1755
1756/* Core methods for SPI master protocol drivers. Some of the
1757 * other core methods are currently defined as inline functions.
1758 */
1759
1760/**
1761 * spi_setup - setup SPI mode and clock rate
1762 * @spi: the device whose settings are being modified
1763 * Context: can sleep, and no requests are queued to the device
1764 *
1765 * SPI protocol drivers may need to update the transfer mode if the
1766 * device doesn't work with its default. They may likewise need
1767 * to update clock rates or word sizes from initial values. This function
1768 * changes those settings, and must be called from a context that can sleep.
1769 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1770 * effect the next time the device is selected and data is transferred to
1771 * or from it. When this function returns, the spi device is deselected.
1772 *
1773 * Note that this call will fail if the protocol driver specifies an option
1774 * that the underlying controller or its driver does not support. For
1775 * example, not all hardware supports wire transfers using nine bit words,
1776 * LSB-first wire encoding, or active-high chipselects.
1777 */
1778int spi_setup(struct spi_device *spi)
1779{
1780 unsigned bad_bits, ugly_bits;
1781 int status = 0;
1782
1783 /* check mode to prevent that DUAL and QUAD set at the same time
1784 */
1785 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1786 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1787 dev_err(&spi->dev,
1788 "setup: can not select dual and quad at the same time\n");
1789 return -EINVAL;
1790 }
1791 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1792 */
1793 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1794 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1795 return -EINVAL;
1796 /* help drivers fail *cleanly* when they need options
1797 * that aren't supported with their current master
1798 */
1799 bad_bits = spi->mode & ~spi->master->mode_bits;
1800 ugly_bits = bad_bits &
1801 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1802 if (ugly_bits) {
1803 dev_warn(&spi->dev,
1804 "setup: ignoring unsupported mode bits %x\n",
1805 ugly_bits);
1806 spi->mode &= ~ugly_bits;
1807 bad_bits &= ~ugly_bits;
1808 }
1809 if (bad_bits) {
1810 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1811 bad_bits);
1812 return -EINVAL;
1813 }
1814
1815 if (!spi->bits_per_word)
1816 spi->bits_per_word = 8;
1817
1818 if (!spi->max_speed_hz)
1819 spi->max_speed_hz = spi->master->max_speed_hz;
1820
1821 if (spi->master->setup)
1822 status = spi->master->setup(spi);
1823
1824 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1825 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1826 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1827 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1828 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1829 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1830 spi->bits_per_word, spi->max_speed_hz,
1831 status);
1832
1833 return status;
1834}
1835EXPORT_SYMBOL_GPL(spi_setup);
1836
1837static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1838{
1839 struct spi_master *master = spi->master;
1840 struct spi_transfer *xfer;
1841 int w_size;
1842
1843 if (list_empty(&message->transfers))
1844 return -EINVAL;
1845
1846 /* Half-duplex links include original MicroWire, and ones with
1847 * only one data pin like SPI_3WIRE (switches direction) or where
1848 * either MOSI or MISO is missing. They can also be caused by
1849 * software limitations.
1850 */
1851 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1852 || (spi->mode & SPI_3WIRE)) {
1853 unsigned flags = master->flags;
1854
1855 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1856 if (xfer->rx_buf && xfer->tx_buf)
1857 return -EINVAL;
1858 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1859 return -EINVAL;
1860 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1861 return -EINVAL;
1862 }
1863 }
1864
1865 /**
1866 * Set transfer bits_per_word and max speed as spi device default if
1867 * it is not set for this transfer.
1868 * Set transfer tx_nbits and rx_nbits as single transfer default
1869 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1870 */
1871 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1872 message->frame_length += xfer->len;
1873 if (!xfer->bits_per_word)
1874 xfer->bits_per_word = spi->bits_per_word;
1875
1876 if (!xfer->speed_hz)
1877 xfer->speed_hz = spi->max_speed_hz;
1878
1879 if (master->max_speed_hz &&
1880 xfer->speed_hz > master->max_speed_hz)
1881 xfer->speed_hz = master->max_speed_hz;
1882
1883 if (master->bits_per_word_mask) {
1884 /* Only 32 bits fit in the mask */
1885 if (xfer->bits_per_word > 32)
1886 return -EINVAL;
1887 if (!(master->bits_per_word_mask &
1888 BIT(xfer->bits_per_word - 1)))
1889 return -EINVAL;
1890 }
1891
1892 /*
1893 * SPI transfer length should be multiple of SPI word size
1894 * where SPI word size should be power-of-two multiple
1895 */
1896 if (xfer->bits_per_word <= 8)
1897 w_size = 1;
1898 else if (xfer->bits_per_word <= 16)
1899 w_size = 2;
1900 else
1901 w_size = 4;
1902
1903 /* No partial transfers accepted */
1904 if (xfer->len % w_size)
1905 return -EINVAL;
1906
1907 if (xfer->speed_hz && master->min_speed_hz &&
1908 xfer->speed_hz < master->min_speed_hz)
1909 return -EINVAL;
1910
1911 if (xfer->tx_buf && !xfer->tx_nbits)
1912 xfer->tx_nbits = SPI_NBITS_SINGLE;
1913 if (xfer->rx_buf && !xfer->rx_nbits)
1914 xfer->rx_nbits = SPI_NBITS_SINGLE;
1915 /* check transfer tx/rx_nbits:
1916 * 1. check the value matches one of single, dual and quad
1917 * 2. check tx/rx_nbits match the mode in spi_device
1918 */
1919 if (xfer->tx_buf) {
1920 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1921 xfer->tx_nbits != SPI_NBITS_DUAL &&
1922 xfer->tx_nbits != SPI_NBITS_QUAD)
1923 return -EINVAL;
1924 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1925 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1926 return -EINVAL;
1927 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1928 !(spi->mode & SPI_TX_QUAD))
1929 return -EINVAL;
1930 }
1931 /* check transfer rx_nbits */
1932 if (xfer->rx_buf) {
1933 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1934 xfer->rx_nbits != SPI_NBITS_DUAL &&
1935 xfer->rx_nbits != SPI_NBITS_QUAD)
1936 return -EINVAL;
1937 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1938 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1939 return -EINVAL;
1940 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1941 !(spi->mode & SPI_RX_QUAD))
1942 return -EINVAL;
1943 }
1944 }
1945
1946 message->status = -EINPROGRESS;
1947
1948 return 0;
1949}
1950
1951static int __spi_async(struct spi_device *spi, struct spi_message *message)
1952{
1953 struct spi_master *master = spi->master;
1954
1955 message->spi = spi;
1956
1957 trace_spi_message_submit(message);
1958
1959 return master->transfer(spi, message);
1960}
1961
1962/**
1963 * spi_async - asynchronous SPI transfer
1964 * @spi: device with which data will be exchanged
1965 * @message: describes the data transfers, including completion callback
1966 * Context: any (irqs may be blocked, etc)
1967 *
1968 * This call may be used in_irq and other contexts which can't sleep,
1969 * as well as from task contexts which can sleep.
1970 *
1971 * The completion callback is invoked in a context which can't sleep.
1972 * Before that invocation, the value of message->status is undefined.
1973 * When the callback is issued, message->status holds either zero (to
1974 * indicate complete success) or a negative error code. After that
1975 * callback returns, the driver which issued the transfer request may
1976 * deallocate the associated memory; it's no longer in use by any SPI
1977 * core or controller driver code.
1978 *
1979 * Note that although all messages to a spi_device are handled in
1980 * FIFO order, messages may go to different devices in other orders.
1981 * Some device might be higher priority, or have various "hard" access
1982 * time requirements, for example.
1983 *
1984 * On detection of any fault during the transfer, processing of
1985 * the entire message is aborted, and the device is deselected.
1986 * Until returning from the associated message completion callback,
1987 * no other spi_message queued to that device will be processed.
1988 * (This rule applies equally to all the synchronous transfer calls,
1989 * which are wrappers around this core asynchronous primitive.)
1990 */
1991int spi_async(struct spi_device *spi, struct spi_message *message)
1992{
1993 struct spi_master *master = spi->master;
1994 int ret;
1995 unsigned long flags;
1996
1997 ret = __spi_validate(spi, message);
1998 if (ret != 0)
1999 return ret;
2000
2001 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2002
2003 if (master->bus_lock_flag)
2004 ret = -EBUSY;
2005 else
2006 ret = __spi_async(spi, message);
2007
2008 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2009
2010 return ret;
2011}
2012EXPORT_SYMBOL_GPL(spi_async);
2013
2014/**
2015 * spi_async_locked - version of spi_async with exclusive bus usage
2016 * @spi: device with which data will be exchanged
2017 * @message: describes the data transfers, including completion callback
2018 * Context: any (irqs may be blocked, etc)
2019 *
2020 * This call may be used in_irq and other contexts which can't sleep,
2021 * as well as from task contexts which can sleep.
2022 *
2023 * The completion callback is invoked in a context which can't sleep.
2024 * Before that invocation, the value of message->status is undefined.
2025 * When the callback is issued, message->status holds either zero (to
2026 * indicate complete success) or a negative error code. After that
2027 * callback returns, the driver which issued the transfer request may
2028 * deallocate the associated memory; it's no longer in use by any SPI
2029 * core or controller driver code.
2030 *
2031 * Note that although all messages to a spi_device are handled in
2032 * FIFO order, messages may go to different devices in other orders.
2033 * Some device might be higher priority, or have various "hard" access
2034 * time requirements, for example.
2035 *
2036 * On detection of any fault during the transfer, processing of
2037 * the entire message is aborted, and the device is deselected.
2038 * Until returning from the associated message completion callback,
2039 * no other spi_message queued to that device will be processed.
2040 * (This rule applies equally to all the synchronous transfer calls,
2041 * which are wrappers around this core asynchronous primitive.)
2042 */
2043int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2044{
2045 struct spi_master *master = spi->master;
2046 int ret;
2047 unsigned long flags;
2048
2049 ret = __spi_validate(spi, message);
2050 if (ret != 0)
2051 return ret;
2052
2053 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2054
2055 ret = __spi_async(spi, message);
2056
2057 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2058
2059 return ret;
2060
2061}
2062EXPORT_SYMBOL_GPL(spi_async_locked);
2063
2064
2065/*-------------------------------------------------------------------------*/
2066
2067/* Utility methods for SPI master protocol drivers, layered on
2068 * top of the core. Some other utility methods are defined as
2069 * inline functions.
2070 */
2071
2072static void spi_complete(void *arg)
2073{
2074 complete(arg);
2075}
2076
2077static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2078 int bus_locked)
2079{
2080 DECLARE_COMPLETION_ONSTACK(done);
2081 int status;
2082 struct spi_master *master = spi->master;
2083
2084 message->complete = spi_complete;
2085 message->context = &done;
2086
2087 if (!bus_locked)
2088 mutex_lock(&master->bus_lock_mutex);
2089
2090 status = spi_async_locked(spi, message);
2091
2092 if (!bus_locked)
2093 mutex_unlock(&master->bus_lock_mutex);
2094
2095 if (status == 0) {
2096 wait_for_completion(&done);
2097 status = message->status;
2098 }
2099 message->context = NULL;
2100 return status;
2101}
2102
2103/**
2104 * spi_sync - blocking/synchronous SPI data transfers
2105 * @spi: device with which data will be exchanged
2106 * @message: describes the data transfers
2107 * Context: can sleep
2108 *
2109 * This call may only be used from a context that may sleep. The sleep
2110 * is non-interruptible, and has no timeout. Low-overhead controller
2111 * drivers may DMA directly into and out of the message buffers.
2112 *
2113 * Note that the SPI device's chip select is active during the message,
2114 * and then is normally disabled between messages. Drivers for some
2115 * frequently-used devices may want to minimize costs of selecting a chip,
2116 * by leaving it selected in anticipation that the next message will go
2117 * to the same chip. (That may increase power usage.)
2118 *
2119 * Also, the caller is guaranteeing that the memory associated with the
2120 * message will not be freed before this call returns.
2121 *
2122 * It returns zero on success, else a negative error code.
2123 */
2124int spi_sync(struct spi_device *spi, struct spi_message *message)
2125{
2126 return __spi_sync(spi, message, 0);
2127}
2128EXPORT_SYMBOL_GPL(spi_sync);
2129
2130/**
2131 * spi_sync_locked - version of spi_sync with exclusive bus usage
2132 * @spi: device with which data will be exchanged
2133 * @message: describes the data transfers
2134 * Context: can sleep
2135 *
2136 * This call may only be used from a context that may sleep. The sleep
2137 * is non-interruptible, and has no timeout. Low-overhead controller
2138 * drivers may DMA directly into and out of the message buffers.
2139 *
2140 * This call should be used by drivers that require exclusive access to the
2141 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2142 * be released by a spi_bus_unlock call when the exclusive access is over.
2143 *
2144 * It returns zero on success, else a negative error code.
2145 */
2146int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2147{
2148 return __spi_sync(spi, message, 1);
2149}
2150EXPORT_SYMBOL_GPL(spi_sync_locked);
2151
2152/**
2153 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2154 * @master: SPI bus master that should be locked for exclusive bus access
2155 * Context: can sleep
2156 *
2157 * This call may only be used from a context that may sleep. The sleep
2158 * is non-interruptible, and has no timeout.
2159 *
2160 * This call should be used by drivers that require exclusive access to the
2161 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2162 * exclusive access is over. Data transfer must be done by spi_sync_locked
2163 * and spi_async_locked calls when the SPI bus lock is held.
2164 *
2165 * It returns zero on success, else a negative error code.
2166 */
2167int spi_bus_lock(struct spi_master *master)
2168{
2169 unsigned long flags;
2170
2171 mutex_lock(&master->bus_lock_mutex);
2172
2173 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2174 master->bus_lock_flag = 1;
2175 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2176
2177 /* mutex remains locked until spi_bus_unlock is called */
2178
2179 return 0;
2180}
2181EXPORT_SYMBOL_GPL(spi_bus_lock);
2182
2183/**
2184 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2185 * @master: SPI bus master that was locked for exclusive bus access
2186 * Context: can sleep
2187 *
2188 * This call may only be used from a context that may sleep. The sleep
2189 * is non-interruptible, and has no timeout.
2190 *
2191 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2192 * call.
2193 *
2194 * It returns zero on success, else a negative error code.
2195 */
2196int spi_bus_unlock(struct spi_master *master)
2197{
2198 master->bus_lock_flag = 0;
2199
2200 mutex_unlock(&master->bus_lock_mutex);
2201
2202 return 0;
2203}
2204EXPORT_SYMBOL_GPL(spi_bus_unlock);
2205
2206/* portable code must never pass more than 32 bytes */
2207#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2208
2209static u8 *buf;
2210
2211/**
2212 * spi_write_then_read - SPI synchronous write followed by read
2213 * @spi: device with which data will be exchanged
2214 * @txbuf: data to be written (need not be dma-safe)
2215 * @n_tx: size of txbuf, in bytes
2216 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2217 * @n_rx: size of rxbuf, in bytes
2218 * Context: can sleep
2219 *
2220 * This performs a half duplex MicroWire style transaction with the
2221 * device, sending txbuf and then reading rxbuf. The return value
2222 * is zero for success, else a negative errno status code.
2223 * This call may only be used from a context that may sleep.
2224 *
2225 * Parameters to this routine are always copied using a small buffer;
2226 * portable code should never use this for more than 32 bytes.
2227 * Performance-sensitive or bulk transfer code should instead use
2228 * spi_{async,sync}() calls with dma-safe buffers.
2229 */
2230int spi_write_then_read(struct spi_device *spi,
2231 const void *txbuf, unsigned n_tx,
2232 void *rxbuf, unsigned n_rx)
2233{
2234 static DEFINE_MUTEX(lock);
2235
2236 int status;
2237 struct spi_message message;
2238 struct spi_transfer x[2];
2239 u8 *local_buf;
2240
2241 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2242 * copying here, (as a pure convenience thing), but we can
2243 * keep heap costs out of the hot path unless someone else is
2244 * using the pre-allocated buffer or the transfer is too large.
2245 */
2246 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2247 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2248 GFP_KERNEL | GFP_DMA);
2249 if (!local_buf)
2250 return -ENOMEM;
2251 } else {
2252 local_buf = buf;
2253 }
2254
2255 spi_message_init(&message);
2256 memset(x, 0, sizeof(x));
2257 if (n_tx) {
2258 x[0].len = n_tx;
2259 spi_message_add_tail(&x[0], &message);
2260 }
2261 if (n_rx) {
2262 x[1].len = n_rx;
2263 spi_message_add_tail(&x[1], &message);
2264 }
2265
2266 memcpy(local_buf, txbuf, n_tx);
2267 x[0].tx_buf = local_buf;
2268 x[1].rx_buf = local_buf + n_tx;
2269
2270 /* do the i/o */
2271 status = spi_sync(spi, &message);
2272 if (status == 0)
2273 memcpy(rxbuf, x[1].rx_buf, n_rx);
2274
2275 if (x[0].tx_buf == buf)
2276 mutex_unlock(&lock);
2277 else
2278 kfree(local_buf);
2279
2280 return status;
2281}
2282EXPORT_SYMBOL_GPL(spi_write_then_read);
2283
2284/*-------------------------------------------------------------------------*/
2285
2286static int __init spi_init(void)
2287{
2288 int status;
2289
2290 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2291 if (!buf) {
2292 status = -ENOMEM;
2293 goto err0;
2294 }
2295
2296 status = bus_register(&spi_bus_type);
2297 if (status < 0)
2298 goto err1;
2299
2300 status = class_register(&spi_master_class);
2301 if (status < 0)
2302 goto err2;
2303 return 0;
2304
2305err2:
2306 bus_unregister(&spi_bus_type);
2307err1:
2308 kfree(buf);
2309 buf = NULL;
2310err0:
2311 return status;
2312}
2313
2314/* board_info is normally registered in arch_initcall(),
2315 * but even essential drivers wait till later
2316 *
2317 * REVISIT only boardinfo really needs static linking. the rest (device and
2318 * driver registration) _could_ be dynamically linked (modular) ... costs
2319 * include needing to have boardinfo data structures be much more public.
2320 */
2321postcore_initcall(spi_init);
2322