Merge remote-tracking branches 'spi/topic/rockchip', 'spi/topic/rspi', 'spi/topic...
[sfrench/cifs-2.6.git] / drivers / spi / spi.c
1 /*
2  * SPI init/core code
3  *
4  * Copyright (C) 2005 David Brownell
5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
40 #include <linux/highmem.h>
41
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/spi.h>
44
45 static void spidev_release(struct device *dev)
46 {
47         struct spi_device       *spi = to_spi_device(dev);
48
49         /* spi masters may cleanup for released devices */
50         if (spi->master->cleanup)
51                 spi->master->cleanup(spi);
52
53         spi_master_put(spi->master);
54         kfree(spi);
55 }
56
57 static ssize_t
58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 {
60         const struct spi_device *spi = to_spi_device(dev);
61         int len;
62
63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
64         if (len != -ENODEV)
65                 return len;
66
67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 }
69 static DEVICE_ATTR_RO(modalias);
70
71 #define SPI_STATISTICS_ATTRS(field, file)                               \
72 static ssize_t spi_master_##field##_show(struct device *dev,            \
73                                          struct device_attribute *attr, \
74                                          char *buf)                     \
75 {                                                                       \
76         struct spi_master *master = container_of(dev,                   \
77                                                  struct spi_master, dev); \
78         return spi_statistics_##field##_show(&master->statistics, buf); \
79 }                                                                       \
80 static struct device_attribute dev_attr_spi_master_##field = {          \
81         .attr = { .name = file, .mode = S_IRUGO },                      \
82         .show = spi_master_##field##_show,                              \
83 };                                                                      \
84 static ssize_t spi_device_##field##_show(struct device *dev,            \
85                                          struct device_attribute *attr, \
86                                         char *buf)                      \
87 {                                                                       \
88         struct spi_device *spi = to_spi_device(dev);                    \
89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
90 }                                                                       \
91 static struct device_attribute dev_attr_spi_device_##field = {          \
92         .attr = { .name = file, .mode = S_IRUGO },                      \
93         .show = spi_device_##field##_show,                              \
94 }
95
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
98                                             char *buf)                  \
99 {                                                                       \
100         unsigned long flags;                                            \
101         ssize_t len;                                                    \
102         spin_lock_irqsave(&stat->lock, flags);                          \
103         len = sprintf(buf, format_string, stat->field);                 \
104         spin_unlock_irqrestore(&stat->lock, flags);                     \
105         return len;                                                     \
106 }                                                                       \
107 SPI_STATISTICS_ATTRS(name, file)
108
109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
111                                  field, format_string)
112
113 SPI_STATISTICS_SHOW(messages, "%lu");
114 SPI_STATISTICS_SHOW(transfers, "%lu");
115 SPI_STATISTICS_SHOW(errors, "%lu");
116 SPI_STATISTICS_SHOW(timedout, "%lu");
117
118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120 SPI_STATISTICS_SHOW(spi_async, "%lu");
121
122 SPI_STATISTICS_SHOW(bytes, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125
126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
128                                  "transfer_bytes_histo_" number,        \
129                                  transfer_bytes_histo[index],  "%lu")
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147
148 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
149
150 static struct attribute *spi_dev_attrs[] = {
151         &dev_attr_modalias.attr,
152         NULL,
153 };
154
155 static const struct attribute_group spi_dev_group = {
156         .attrs  = spi_dev_attrs,
157 };
158
159 static struct attribute *spi_device_statistics_attrs[] = {
160         &dev_attr_spi_device_messages.attr,
161         &dev_attr_spi_device_transfers.attr,
162         &dev_attr_spi_device_errors.attr,
163         &dev_attr_spi_device_timedout.attr,
164         &dev_attr_spi_device_spi_sync.attr,
165         &dev_attr_spi_device_spi_sync_immediate.attr,
166         &dev_attr_spi_device_spi_async.attr,
167         &dev_attr_spi_device_bytes.attr,
168         &dev_attr_spi_device_bytes_rx.attr,
169         &dev_attr_spi_device_bytes_tx.attr,
170         &dev_attr_spi_device_transfer_bytes_histo0.attr,
171         &dev_attr_spi_device_transfer_bytes_histo1.attr,
172         &dev_attr_spi_device_transfer_bytes_histo2.attr,
173         &dev_attr_spi_device_transfer_bytes_histo3.attr,
174         &dev_attr_spi_device_transfer_bytes_histo4.attr,
175         &dev_attr_spi_device_transfer_bytes_histo5.attr,
176         &dev_attr_spi_device_transfer_bytes_histo6.attr,
177         &dev_attr_spi_device_transfer_bytes_histo7.attr,
178         &dev_attr_spi_device_transfer_bytes_histo8.attr,
179         &dev_attr_spi_device_transfer_bytes_histo9.attr,
180         &dev_attr_spi_device_transfer_bytes_histo10.attr,
181         &dev_attr_spi_device_transfer_bytes_histo11.attr,
182         &dev_attr_spi_device_transfer_bytes_histo12.attr,
183         &dev_attr_spi_device_transfer_bytes_histo13.attr,
184         &dev_attr_spi_device_transfer_bytes_histo14.attr,
185         &dev_attr_spi_device_transfer_bytes_histo15.attr,
186         &dev_attr_spi_device_transfer_bytes_histo16.attr,
187         &dev_attr_spi_device_transfers_split_maxsize.attr,
188         NULL,
189 };
190
191 static const struct attribute_group spi_device_statistics_group = {
192         .name  = "statistics",
193         .attrs  = spi_device_statistics_attrs,
194 };
195
196 static const struct attribute_group *spi_dev_groups[] = {
197         &spi_dev_group,
198         &spi_device_statistics_group,
199         NULL,
200 };
201
202 static struct attribute *spi_master_statistics_attrs[] = {
203         &dev_attr_spi_master_messages.attr,
204         &dev_attr_spi_master_transfers.attr,
205         &dev_attr_spi_master_errors.attr,
206         &dev_attr_spi_master_timedout.attr,
207         &dev_attr_spi_master_spi_sync.attr,
208         &dev_attr_spi_master_spi_sync_immediate.attr,
209         &dev_attr_spi_master_spi_async.attr,
210         &dev_attr_spi_master_bytes.attr,
211         &dev_attr_spi_master_bytes_rx.attr,
212         &dev_attr_spi_master_bytes_tx.attr,
213         &dev_attr_spi_master_transfer_bytes_histo0.attr,
214         &dev_attr_spi_master_transfer_bytes_histo1.attr,
215         &dev_attr_spi_master_transfer_bytes_histo2.attr,
216         &dev_attr_spi_master_transfer_bytes_histo3.attr,
217         &dev_attr_spi_master_transfer_bytes_histo4.attr,
218         &dev_attr_spi_master_transfer_bytes_histo5.attr,
219         &dev_attr_spi_master_transfer_bytes_histo6.attr,
220         &dev_attr_spi_master_transfer_bytes_histo7.attr,
221         &dev_attr_spi_master_transfer_bytes_histo8.attr,
222         &dev_attr_spi_master_transfer_bytes_histo9.attr,
223         &dev_attr_spi_master_transfer_bytes_histo10.attr,
224         &dev_attr_spi_master_transfer_bytes_histo11.attr,
225         &dev_attr_spi_master_transfer_bytes_histo12.attr,
226         &dev_attr_spi_master_transfer_bytes_histo13.attr,
227         &dev_attr_spi_master_transfer_bytes_histo14.attr,
228         &dev_attr_spi_master_transfer_bytes_histo15.attr,
229         &dev_attr_spi_master_transfer_bytes_histo16.attr,
230         &dev_attr_spi_master_transfers_split_maxsize.attr,
231         NULL,
232 };
233
234 static const struct attribute_group spi_master_statistics_group = {
235         .name  = "statistics",
236         .attrs  = spi_master_statistics_attrs,
237 };
238
239 static const struct attribute_group *spi_master_groups[] = {
240         &spi_master_statistics_group,
241         NULL,
242 };
243
244 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
245                                        struct spi_transfer *xfer,
246                                        struct spi_master *master)
247 {
248         unsigned long flags;
249         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
250
251         if (l2len < 0)
252                 l2len = 0;
253
254         spin_lock_irqsave(&stats->lock, flags);
255
256         stats->transfers++;
257         stats->transfer_bytes_histo[l2len]++;
258
259         stats->bytes += xfer->len;
260         if ((xfer->tx_buf) &&
261             (xfer->tx_buf != master->dummy_tx))
262                 stats->bytes_tx += xfer->len;
263         if ((xfer->rx_buf) &&
264             (xfer->rx_buf != master->dummy_rx))
265                 stats->bytes_rx += xfer->len;
266
267         spin_unlock_irqrestore(&stats->lock, flags);
268 }
269 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
270
271 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
272  * and the sysfs version makes coldplug work too.
273  */
274
275 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
276                                                 const struct spi_device *sdev)
277 {
278         while (id->name[0]) {
279                 if (!strcmp(sdev->modalias, id->name))
280                         return id;
281                 id++;
282         }
283         return NULL;
284 }
285
286 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
287 {
288         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
289
290         return spi_match_id(sdrv->id_table, sdev);
291 }
292 EXPORT_SYMBOL_GPL(spi_get_device_id);
293
294 static int spi_match_device(struct device *dev, struct device_driver *drv)
295 {
296         const struct spi_device *spi = to_spi_device(dev);
297         const struct spi_driver *sdrv = to_spi_driver(drv);
298
299         /* Attempt an OF style match */
300         if (of_driver_match_device(dev, drv))
301                 return 1;
302
303         /* Then try ACPI */
304         if (acpi_driver_match_device(dev, drv))
305                 return 1;
306
307         if (sdrv->id_table)
308                 return !!spi_match_id(sdrv->id_table, spi);
309
310         return strcmp(spi->modalias, drv->name) == 0;
311 }
312
313 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
314 {
315         const struct spi_device         *spi = to_spi_device(dev);
316         int rc;
317
318         rc = acpi_device_uevent_modalias(dev, env);
319         if (rc != -ENODEV)
320                 return rc;
321
322         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
323         return 0;
324 }
325
326 struct bus_type spi_bus_type = {
327         .name           = "spi",
328         .dev_groups     = spi_dev_groups,
329         .match          = spi_match_device,
330         .uevent         = spi_uevent,
331 };
332 EXPORT_SYMBOL_GPL(spi_bus_type);
333
334
335 static int spi_drv_probe(struct device *dev)
336 {
337         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
338         struct spi_device               *spi = to_spi_device(dev);
339         int ret;
340
341         ret = of_clk_set_defaults(dev->of_node, false);
342         if (ret)
343                 return ret;
344
345         if (dev->of_node) {
346                 spi->irq = of_irq_get(dev->of_node, 0);
347                 if (spi->irq == -EPROBE_DEFER)
348                         return -EPROBE_DEFER;
349                 if (spi->irq < 0)
350                         spi->irq = 0;
351         }
352
353         ret = dev_pm_domain_attach(dev, true);
354         if (ret != -EPROBE_DEFER) {
355                 ret = sdrv->probe(spi);
356                 if (ret)
357                         dev_pm_domain_detach(dev, true);
358         }
359
360         return ret;
361 }
362
363 static int spi_drv_remove(struct device *dev)
364 {
365         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
366         int ret;
367
368         ret = sdrv->remove(to_spi_device(dev));
369         dev_pm_domain_detach(dev, true);
370
371         return ret;
372 }
373
374 static void spi_drv_shutdown(struct device *dev)
375 {
376         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
377
378         sdrv->shutdown(to_spi_device(dev));
379 }
380
381 /**
382  * __spi_register_driver - register a SPI driver
383  * @owner: owner module of the driver to register
384  * @sdrv: the driver to register
385  * Context: can sleep
386  *
387  * Return: zero on success, else a negative error code.
388  */
389 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
390 {
391         sdrv->driver.owner = owner;
392         sdrv->driver.bus = &spi_bus_type;
393         if (sdrv->probe)
394                 sdrv->driver.probe = spi_drv_probe;
395         if (sdrv->remove)
396                 sdrv->driver.remove = spi_drv_remove;
397         if (sdrv->shutdown)
398                 sdrv->driver.shutdown = spi_drv_shutdown;
399         return driver_register(&sdrv->driver);
400 }
401 EXPORT_SYMBOL_GPL(__spi_register_driver);
402
403 /*-------------------------------------------------------------------------*/
404
405 /* SPI devices should normally not be created by SPI device drivers; that
406  * would make them board-specific.  Similarly with SPI master drivers.
407  * Device registration normally goes into like arch/.../mach.../board-YYY.c
408  * with other readonly (flashable) information about mainboard devices.
409  */
410
411 struct boardinfo {
412         struct list_head        list;
413         struct spi_board_info   board_info;
414 };
415
416 static LIST_HEAD(board_list);
417 static LIST_HEAD(spi_master_list);
418
419 /*
420  * Used to protect add/del opertion for board_info list and
421  * spi_master list, and their matching process
422  */
423 static DEFINE_MUTEX(board_lock);
424
425 /**
426  * spi_alloc_device - Allocate a new SPI device
427  * @master: Controller to which device is connected
428  * Context: can sleep
429  *
430  * Allows a driver to allocate and initialize a spi_device without
431  * registering it immediately.  This allows a driver to directly
432  * fill the spi_device with device parameters before calling
433  * spi_add_device() on it.
434  *
435  * Caller is responsible to call spi_add_device() on the returned
436  * spi_device structure to add it to the SPI master.  If the caller
437  * needs to discard the spi_device without adding it, then it should
438  * call spi_dev_put() on it.
439  *
440  * Return: a pointer to the new device, or NULL.
441  */
442 struct spi_device *spi_alloc_device(struct spi_master *master)
443 {
444         struct spi_device       *spi;
445
446         if (!spi_master_get(master))
447                 return NULL;
448
449         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
450         if (!spi) {
451                 spi_master_put(master);
452                 return NULL;
453         }
454
455         spi->master = master;
456         spi->dev.parent = &master->dev;
457         spi->dev.bus = &spi_bus_type;
458         spi->dev.release = spidev_release;
459         spi->cs_gpio = -ENOENT;
460
461         spin_lock_init(&spi->statistics.lock);
462
463         device_initialize(&spi->dev);
464         return spi;
465 }
466 EXPORT_SYMBOL_GPL(spi_alloc_device);
467
468 static void spi_dev_set_name(struct spi_device *spi)
469 {
470         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
471
472         if (adev) {
473                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
474                 return;
475         }
476
477         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
478                      spi->chip_select);
479 }
480
481 static int spi_dev_check(struct device *dev, void *data)
482 {
483         struct spi_device *spi = to_spi_device(dev);
484         struct spi_device *new_spi = data;
485
486         if (spi->master == new_spi->master &&
487             spi->chip_select == new_spi->chip_select)
488                 return -EBUSY;
489         return 0;
490 }
491
492 /**
493  * spi_add_device - Add spi_device allocated with spi_alloc_device
494  * @spi: spi_device to register
495  *
496  * Companion function to spi_alloc_device.  Devices allocated with
497  * spi_alloc_device can be added onto the spi bus with this function.
498  *
499  * Return: 0 on success; negative errno on failure
500  */
501 int spi_add_device(struct spi_device *spi)
502 {
503         static DEFINE_MUTEX(spi_add_lock);
504         struct spi_master *master = spi->master;
505         struct device *dev = master->dev.parent;
506         int status;
507
508         /* Chipselects are numbered 0..max; validate. */
509         if (spi->chip_select >= master->num_chipselect) {
510                 dev_err(dev, "cs%d >= max %d\n",
511                         spi->chip_select,
512                         master->num_chipselect);
513                 return -EINVAL;
514         }
515
516         /* Set the bus ID string */
517         spi_dev_set_name(spi);
518
519         /* We need to make sure there's no other device with this
520          * chipselect **BEFORE** we call setup(), else we'll trash
521          * its configuration.  Lock against concurrent add() calls.
522          */
523         mutex_lock(&spi_add_lock);
524
525         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
526         if (status) {
527                 dev_err(dev, "chipselect %d already in use\n",
528                                 spi->chip_select);
529                 goto done;
530         }
531
532         if (master->cs_gpios)
533                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
534
535         /* Drivers may modify this initial i/o setup, but will
536          * normally rely on the device being setup.  Devices
537          * using SPI_CS_HIGH can't coexist well otherwise...
538          */
539         status = spi_setup(spi);
540         if (status < 0) {
541                 dev_err(dev, "can't setup %s, status %d\n",
542                                 dev_name(&spi->dev), status);
543                 goto done;
544         }
545
546         /* Device may be bound to an active driver when this returns */
547         status = device_add(&spi->dev);
548         if (status < 0)
549                 dev_err(dev, "can't add %s, status %d\n",
550                                 dev_name(&spi->dev), status);
551         else
552                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
553
554 done:
555         mutex_unlock(&spi_add_lock);
556         return status;
557 }
558 EXPORT_SYMBOL_GPL(spi_add_device);
559
560 /**
561  * spi_new_device - instantiate one new SPI device
562  * @master: Controller to which device is connected
563  * @chip: Describes the SPI device
564  * Context: can sleep
565  *
566  * On typical mainboards, this is purely internal; and it's not needed
567  * after board init creates the hard-wired devices.  Some development
568  * platforms may not be able to use spi_register_board_info though, and
569  * this is exported so that for example a USB or parport based adapter
570  * driver could add devices (which it would learn about out-of-band).
571  *
572  * Return: the new device, or NULL.
573  */
574 struct spi_device *spi_new_device(struct spi_master *master,
575                                   struct spi_board_info *chip)
576 {
577         struct spi_device       *proxy;
578         int                     status;
579
580         /* NOTE:  caller did any chip->bus_num checks necessary.
581          *
582          * Also, unless we change the return value convention to use
583          * error-or-pointer (not NULL-or-pointer), troubleshootability
584          * suggests syslogged diagnostics are best here (ugh).
585          */
586
587         proxy = spi_alloc_device(master);
588         if (!proxy)
589                 return NULL;
590
591         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
592
593         proxy->chip_select = chip->chip_select;
594         proxy->max_speed_hz = chip->max_speed_hz;
595         proxy->mode = chip->mode;
596         proxy->irq = chip->irq;
597         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
598         proxy->dev.platform_data = (void *) chip->platform_data;
599         proxy->controller_data = chip->controller_data;
600         proxy->controller_state = NULL;
601
602         status = spi_add_device(proxy);
603         if (status < 0) {
604                 spi_dev_put(proxy);
605                 return NULL;
606         }
607
608         return proxy;
609 }
610 EXPORT_SYMBOL_GPL(spi_new_device);
611
612 /**
613  * spi_unregister_device - unregister a single SPI device
614  * @spi: spi_device to unregister
615  *
616  * Start making the passed SPI device vanish. Normally this would be handled
617  * by spi_unregister_master().
618  */
619 void spi_unregister_device(struct spi_device *spi)
620 {
621         if (!spi)
622                 return;
623
624         if (spi->dev.of_node) {
625                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
626                 of_node_put(spi->dev.of_node);
627         }
628         if (ACPI_COMPANION(&spi->dev))
629                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
630         device_unregister(&spi->dev);
631 }
632 EXPORT_SYMBOL_GPL(spi_unregister_device);
633
634 static void spi_match_master_to_boardinfo(struct spi_master *master,
635                                 struct spi_board_info *bi)
636 {
637         struct spi_device *dev;
638
639         if (master->bus_num != bi->bus_num)
640                 return;
641
642         dev = spi_new_device(master, bi);
643         if (!dev)
644                 dev_err(master->dev.parent, "can't create new device for %s\n",
645                         bi->modalias);
646 }
647
648 /**
649  * spi_register_board_info - register SPI devices for a given board
650  * @info: array of chip descriptors
651  * @n: how many descriptors are provided
652  * Context: can sleep
653  *
654  * Board-specific early init code calls this (probably during arch_initcall)
655  * with segments of the SPI device table.  Any device nodes are created later,
656  * after the relevant parent SPI controller (bus_num) is defined.  We keep
657  * this table of devices forever, so that reloading a controller driver will
658  * not make Linux forget about these hard-wired devices.
659  *
660  * Other code can also call this, e.g. a particular add-on board might provide
661  * SPI devices through its expansion connector, so code initializing that board
662  * would naturally declare its SPI devices.
663  *
664  * The board info passed can safely be __initdata ... but be careful of
665  * any embedded pointers (platform_data, etc), they're copied as-is.
666  *
667  * Return: zero on success, else a negative error code.
668  */
669 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
670 {
671         struct boardinfo *bi;
672         int i;
673
674         if (!n)
675                 return -EINVAL;
676
677         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
678         if (!bi)
679                 return -ENOMEM;
680
681         for (i = 0; i < n; i++, bi++, info++) {
682                 struct spi_master *master;
683
684                 memcpy(&bi->board_info, info, sizeof(*info));
685                 mutex_lock(&board_lock);
686                 list_add_tail(&bi->list, &board_list);
687                 list_for_each_entry(master, &spi_master_list, list)
688                         spi_match_master_to_boardinfo(master, &bi->board_info);
689                 mutex_unlock(&board_lock);
690         }
691
692         return 0;
693 }
694
695 /*-------------------------------------------------------------------------*/
696
697 static void spi_set_cs(struct spi_device *spi, bool enable)
698 {
699         if (spi->mode & SPI_CS_HIGH)
700                 enable = !enable;
701
702         if (gpio_is_valid(spi->cs_gpio)) {
703                 gpio_set_value(spi->cs_gpio, !enable);
704                 /* Some SPI masters need both GPIO CS & slave_select */
705                 if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
706                     spi->master->set_cs)
707                         spi->master->set_cs(spi, !enable);
708         } else if (spi->master->set_cs) {
709                 spi->master->set_cs(spi, !enable);
710         }
711 }
712
713 #ifdef CONFIG_HAS_DMA
714 static int spi_map_buf(struct spi_master *master, struct device *dev,
715                        struct sg_table *sgt, void *buf, size_t len,
716                        enum dma_data_direction dir)
717 {
718         const bool vmalloced_buf = is_vmalloc_addr(buf);
719         unsigned int max_seg_size = dma_get_max_seg_size(dev);
720 #ifdef CONFIG_HIGHMEM
721         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
722                                 (unsigned long)buf < (PKMAP_BASE +
723                                         (LAST_PKMAP * PAGE_SIZE)));
724 #else
725         const bool kmap_buf = false;
726 #endif
727         int desc_len;
728         int sgs;
729         struct page *vm_page;
730         struct scatterlist *sg;
731         void *sg_buf;
732         size_t min;
733         int i, ret;
734
735         if (vmalloced_buf || kmap_buf) {
736                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
737                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
738         } else if (virt_addr_valid(buf)) {
739                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
740                 sgs = DIV_ROUND_UP(len, desc_len);
741         } else {
742                 return -EINVAL;
743         }
744
745         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
746         if (ret != 0)
747                 return ret;
748
749         sg = &sgt->sgl[0];
750         for (i = 0; i < sgs; i++) {
751
752                 if (vmalloced_buf || kmap_buf) {
753                         min = min_t(size_t,
754                                     len, desc_len - offset_in_page(buf));
755                         if (vmalloced_buf)
756                                 vm_page = vmalloc_to_page(buf);
757                         else
758                                 vm_page = kmap_to_page(buf);
759                         if (!vm_page) {
760                                 sg_free_table(sgt);
761                                 return -ENOMEM;
762                         }
763                         sg_set_page(sg, vm_page,
764                                     min, offset_in_page(buf));
765                 } else {
766                         min = min_t(size_t, len, desc_len);
767                         sg_buf = buf;
768                         sg_set_buf(sg, sg_buf, min);
769                 }
770
771                 buf += min;
772                 len -= min;
773                 sg = sg_next(sg);
774         }
775
776         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
777         if (!ret)
778                 ret = -ENOMEM;
779         if (ret < 0) {
780                 sg_free_table(sgt);
781                 return ret;
782         }
783
784         sgt->nents = ret;
785
786         return 0;
787 }
788
789 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
790                           struct sg_table *sgt, enum dma_data_direction dir)
791 {
792         if (sgt->orig_nents) {
793                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
794                 sg_free_table(sgt);
795         }
796 }
797
798 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
799 {
800         struct device *tx_dev, *rx_dev;
801         struct spi_transfer *xfer;
802         int ret;
803
804         if (!master->can_dma)
805                 return 0;
806
807         if (master->dma_tx)
808                 tx_dev = master->dma_tx->device->dev;
809         else
810                 tx_dev = master->dev.parent;
811
812         if (master->dma_rx)
813                 rx_dev = master->dma_rx->device->dev;
814         else
815                 rx_dev = master->dev.parent;
816
817         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
818                 if (!master->can_dma(master, msg->spi, xfer))
819                         continue;
820
821                 if (xfer->tx_buf != NULL) {
822                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
823                                           (void *)xfer->tx_buf, xfer->len,
824                                           DMA_TO_DEVICE);
825                         if (ret != 0)
826                                 return ret;
827                 }
828
829                 if (xfer->rx_buf != NULL) {
830                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
831                                           xfer->rx_buf, xfer->len,
832                                           DMA_FROM_DEVICE);
833                         if (ret != 0) {
834                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
835                                               DMA_TO_DEVICE);
836                                 return ret;
837                         }
838                 }
839         }
840
841         master->cur_msg_mapped = true;
842
843         return 0;
844 }
845
846 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
847 {
848         struct spi_transfer *xfer;
849         struct device *tx_dev, *rx_dev;
850
851         if (!master->cur_msg_mapped || !master->can_dma)
852                 return 0;
853
854         if (master->dma_tx)
855                 tx_dev = master->dma_tx->device->dev;
856         else
857                 tx_dev = master->dev.parent;
858
859         if (master->dma_rx)
860                 rx_dev = master->dma_rx->device->dev;
861         else
862                 rx_dev = master->dev.parent;
863
864         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
865                 if (!master->can_dma(master, msg->spi, xfer))
866                         continue;
867
868                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
869                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
870         }
871
872         return 0;
873 }
874 #else /* !CONFIG_HAS_DMA */
875 static inline int spi_map_buf(struct spi_master *master,
876                               struct device *dev, struct sg_table *sgt,
877                               void *buf, size_t len,
878                               enum dma_data_direction dir)
879 {
880         return -EINVAL;
881 }
882
883 static inline void spi_unmap_buf(struct spi_master *master,
884                                  struct device *dev, struct sg_table *sgt,
885                                  enum dma_data_direction dir)
886 {
887 }
888
889 static inline int __spi_map_msg(struct spi_master *master,
890                                 struct spi_message *msg)
891 {
892         return 0;
893 }
894
895 static inline int __spi_unmap_msg(struct spi_master *master,
896                                   struct spi_message *msg)
897 {
898         return 0;
899 }
900 #endif /* !CONFIG_HAS_DMA */
901
902 static inline int spi_unmap_msg(struct spi_master *master,
903                                 struct spi_message *msg)
904 {
905         struct spi_transfer *xfer;
906
907         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
908                 /*
909                  * Restore the original value of tx_buf or rx_buf if they are
910                  * NULL.
911                  */
912                 if (xfer->tx_buf == master->dummy_tx)
913                         xfer->tx_buf = NULL;
914                 if (xfer->rx_buf == master->dummy_rx)
915                         xfer->rx_buf = NULL;
916         }
917
918         return __spi_unmap_msg(master, msg);
919 }
920
921 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
922 {
923         struct spi_transfer *xfer;
924         void *tmp;
925         unsigned int max_tx, max_rx;
926
927         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
928                 max_tx = 0;
929                 max_rx = 0;
930
931                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
932                         if ((master->flags & SPI_MASTER_MUST_TX) &&
933                             !xfer->tx_buf)
934                                 max_tx = max(xfer->len, max_tx);
935                         if ((master->flags & SPI_MASTER_MUST_RX) &&
936                             !xfer->rx_buf)
937                                 max_rx = max(xfer->len, max_rx);
938                 }
939
940                 if (max_tx) {
941                         tmp = krealloc(master->dummy_tx, max_tx,
942                                        GFP_KERNEL | GFP_DMA);
943                         if (!tmp)
944                                 return -ENOMEM;
945                         master->dummy_tx = tmp;
946                         memset(tmp, 0, max_tx);
947                 }
948
949                 if (max_rx) {
950                         tmp = krealloc(master->dummy_rx, max_rx,
951                                        GFP_KERNEL | GFP_DMA);
952                         if (!tmp)
953                                 return -ENOMEM;
954                         master->dummy_rx = tmp;
955                 }
956
957                 if (max_tx || max_rx) {
958                         list_for_each_entry(xfer, &msg->transfers,
959                                             transfer_list) {
960                                 if (!xfer->tx_buf)
961                                         xfer->tx_buf = master->dummy_tx;
962                                 if (!xfer->rx_buf)
963                                         xfer->rx_buf = master->dummy_rx;
964                         }
965                 }
966         }
967
968         return __spi_map_msg(master, msg);
969 }
970
971 /*
972  * spi_transfer_one_message - Default implementation of transfer_one_message()
973  *
974  * This is a standard implementation of transfer_one_message() for
975  * drivers which implement a transfer_one() operation.  It provides
976  * standard handling of delays and chip select management.
977  */
978 static int spi_transfer_one_message(struct spi_master *master,
979                                     struct spi_message *msg)
980 {
981         struct spi_transfer *xfer;
982         bool keep_cs = false;
983         int ret = 0;
984         unsigned long long ms = 1;
985         struct spi_statistics *statm = &master->statistics;
986         struct spi_statistics *stats = &msg->spi->statistics;
987
988         spi_set_cs(msg->spi, true);
989
990         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
991         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
992
993         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
994                 trace_spi_transfer_start(msg, xfer);
995
996                 spi_statistics_add_transfer_stats(statm, xfer, master);
997                 spi_statistics_add_transfer_stats(stats, xfer, master);
998
999                 if (xfer->tx_buf || xfer->rx_buf) {
1000                         reinit_completion(&master->xfer_completion);
1001
1002                         ret = master->transfer_one(master, msg->spi, xfer);
1003                         if (ret < 0) {
1004                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1005                                                                errors);
1006                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1007                                                                errors);
1008                                 dev_err(&msg->spi->dev,
1009                                         "SPI transfer failed: %d\n", ret);
1010                                 goto out;
1011                         }
1012
1013                         if (ret > 0) {
1014                                 ret = 0;
1015                                 ms = 8LL * 1000LL * xfer->len;
1016                                 do_div(ms, xfer->speed_hz);
1017                                 ms += ms + 100; /* some tolerance */
1018
1019                                 if (ms > UINT_MAX)
1020                                         ms = UINT_MAX;
1021
1022                                 ms = wait_for_completion_timeout(&master->xfer_completion,
1023                                                                  msecs_to_jiffies(ms));
1024                         }
1025
1026                         if (ms == 0) {
1027                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1028                                                                timedout);
1029                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1030                                                                timedout);
1031                                 dev_err(&msg->spi->dev,
1032                                         "SPI transfer timed out\n");
1033                                 msg->status = -ETIMEDOUT;
1034                         }
1035                 } else {
1036                         if (xfer->len)
1037                                 dev_err(&msg->spi->dev,
1038                                         "Bufferless transfer has length %u\n",
1039                                         xfer->len);
1040                 }
1041
1042                 trace_spi_transfer_stop(msg, xfer);
1043
1044                 if (msg->status != -EINPROGRESS)
1045                         goto out;
1046
1047                 if (xfer->delay_usecs) {
1048                         u16 us = xfer->delay_usecs;
1049
1050                         if (us <= 10)
1051                                 udelay(us);
1052                         else
1053                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1054                 }
1055
1056                 if (xfer->cs_change) {
1057                         if (list_is_last(&xfer->transfer_list,
1058                                          &msg->transfers)) {
1059                                 keep_cs = true;
1060                         } else {
1061                                 spi_set_cs(msg->spi, false);
1062                                 udelay(10);
1063                                 spi_set_cs(msg->spi, true);
1064                         }
1065                 }
1066
1067                 msg->actual_length += xfer->len;
1068         }
1069
1070 out:
1071         if (ret != 0 || !keep_cs)
1072                 spi_set_cs(msg->spi, false);
1073
1074         if (msg->status == -EINPROGRESS)
1075                 msg->status = ret;
1076
1077         if (msg->status && master->handle_err)
1078                 master->handle_err(master, msg);
1079
1080         spi_res_release(master, msg);
1081
1082         spi_finalize_current_message(master);
1083
1084         return ret;
1085 }
1086
1087 /**
1088  * spi_finalize_current_transfer - report completion of a transfer
1089  * @master: the master reporting completion
1090  *
1091  * Called by SPI drivers using the core transfer_one_message()
1092  * implementation to notify it that the current interrupt driven
1093  * transfer has finished and the next one may be scheduled.
1094  */
1095 void spi_finalize_current_transfer(struct spi_master *master)
1096 {
1097         complete(&master->xfer_completion);
1098 }
1099 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1100
1101 /**
1102  * __spi_pump_messages - function which processes spi message queue
1103  * @master: master to process queue for
1104  * @in_kthread: true if we are in the context of the message pump thread
1105  *
1106  * This function checks if there is any spi message in the queue that
1107  * needs processing and if so call out to the driver to initialize hardware
1108  * and transfer each message.
1109  *
1110  * Note that it is called both from the kthread itself and also from
1111  * inside spi_sync(); the queue extraction handling at the top of the
1112  * function should deal with this safely.
1113  */
1114 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1115 {
1116         unsigned long flags;
1117         bool was_busy = false;
1118         int ret;
1119
1120         /* Lock queue */
1121         spin_lock_irqsave(&master->queue_lock, flags);
1122
1123         /* Make sure we are not already running a message */
1124         if (master->cur_msg) {
1125                 spin_unlock_irqrestore(&master->queue_lock, flags);
1126                 return;
1127         }
1128
1129         /* If another context is idling the device then defer */
1130         if (master->idling) {
1131                 kthread_queue_work(&master->kworker, &master->pump_messages);
1132                 spin_unlock_irqrestore(&master->queue_lock, flags);
1133                 return;
1134         }
1135
1136         /* Check if the queue is idle */
1137         if (list_empty(&master->queue) || !master->running) {
1138                 if (!master->busy) {
1139                         spin_unlock_irqrestore(&master->queue_lock, flags);
1140                         return;
1141                 }
1142
1143                 /* Only do teardown in the thread */
1144                 if (!in_kthread) {
1145                         kthread_queue_work(&master->kworker,
1146                                            &master->pump_messages);
1147                         spin_unlock_irqrestore(&master->queue_lock, flags);
1148                         return;
1149                 }
1150
1151                 master->busy = false;
1152                 master->idling = true;
1153                 spin_unlock_irqrestore(&master->queue_lock, flags);
1154
1155                 kfree(master->dummy_rx);
1156                 master->dummy_rx = NULL;
1157                 kfree(master->dummy_tx);
1158                 master->dummy_tx = NULL;
1159                 if (master->unprepare_transfer_hardware &&
1160                     master->unprepare_transfer_hardware(master))
1161                         dev_err(&master->dev,
1162                                 "failed to unprepare transfer hardware\n");
1163                 if (master->auto_runtime_pm) {
1164                         pm_runtime_mark_last_busy(master->dev.parent);
1165                         pm_runtime_put_autosuspend(master->dev.parent);
1166                 }
1167                 trace_spi_master_idle(master);
1168
1169                 spin_lock_irqsave(&master->queue_lock, flags);
1170                 master->idling = false;
1171                 spin_unlock_irqrestore(&master->queue_lock, flags);
1172                 return;
1173         }
1174
1175         /* Extract head of queue */
1176         master->cur_msg =
1177                 list_first_entry(&master->queue, struct spi_message, queue);
1178
1179         list_del_init(&master->cur_msg->queue);
1180         if (master->busy)
1181                 was_busy = true;
1182         else
1183                 master->busy = true;
1184         spin_unlock_irqrestore(&master->queue_lock, flags);
1185
1186         mutex_lock(&master->io_mutex);
1187
1188         if (!was_busy && master->auto_runtime_pm) {
1189                 ret = pm_runtime_get_sync(master->dev.parent);
1190                 if (ret < 0) {
1191                         dev_err(&master->dev, "Failed to power device: %d\n",
1192                                 ret);
1193                         mutex_unlock(&master->io_mutex);
1194                         return;
1195                 }
1196         }
1197
1198         if (!was_busy)
1199                 trace_spi_master_busy(master);
1200
1201         if (!was_busy && master->prepare_transfer_hardware) {
1202                 ret = master->prepare_transfer_hardware(master);
1203                 if (ret) {
1204                         dev_err(&master->dev,
1205                                 "failed to prepare transfer hardware\n");
1206
1207                         if (master->auto_runtime_pm)
1208                                 pm_runtime_put(master->dev.parent);
1209                         mutex_unlock(&master->io_mutex);
1210                         return;
1211                 }
1212         }
1213
1214         trace_spi_message_start(master->cur_msg);
1215
1216         if (master->prepare_message) {
1217                 ret = master->prepare_message(master, master->cur_msg);
1218                 if (ret) {
1219                         dev_err(&master->dev,
1220                                 "failed to prepare message: %d\n", ret);
1221                         master->cur_msg->status = ret;
1222                         spi_finalize_current_message(master);
1223                         goto out;
1224                 }
1225                 master->cur_msg_prepared = true;
1226         }
1227
1228         ret = spi_map_msg(master, master->cur_msg);
1229         if (ret) {
1230                 master->cur_msg->status = ret;
1231                 spi_finalize_current_message(master);
1232                 goto out;
1233         }
1234
1235         ret = master->transfer_one_message(master, master->cur_msg);
1236         if (ret) {
1237                 dev_err(&master->dev,
1238                         "failed to transfer one message from queue\n");
1239                 goto out;
1240         }
1241
1242 out:
1243         mutex_unlock(&master->io_mutex);
1244
1245         /* Prod the scheduler in case transfer_one() was busy waiting */
1246         if (!ret)
1247                 cond_resched();
1248 }
1249
1250 /**
1251  * spi_pump_messages - kthread work function which processes spi message queue
1252  * @work: pointer to kthread work struct contained in the master struct
1253  */
1254 static void spi_pump_messages(struct kthread_work *work)
1255 {
1256         struct spi_master *master =
1257                 container_of(work, struct spi_master, pump_messages);
1258
1259         __spi_pump_messages(master, true);
1260 }
1261
1262 static int spi_init_queue(struct spi_master *master)
1263 {
1264         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1265
1266         master->running = false;
1267         master->busy = false;
1268
1269         kthread_init_worker(&master->kworker);
1270         master->kworker_task = kthread_run(kthread_worker_fn,
1271                                            &master->kworker, "%s",
1272                                            dev_name(&master->dev));
1273         if (IS_ERR(master->kworker_task)) {
1274                 dev_err(&master->dev, "failed to create message pump task\n");
1275                 return PTR_ERR(master->kworker_task);
1276         }
1277         kthread_init_work(&master->pump_messages, spi_pump_messages);
1278
1279         /*
1280          * Master config will indicate if this controller should run the
1281          * message pump with high (realtime) priority to reduce the transfer
1282          * latency on the bus by minimising the delay between a transfer
1283          * request and the scheduling of the message pump thread. Without this
1284          * setting the message pump thread will remain at default priority.
1285          */
1286         if (master->rt) {
1287                 dev_info(&master->dev,
1288                         "will run message pump with realtime priority\n");
1289                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1290         }
1291
1292         return 0;
1293 }
1294
1295 /**
1296  * spi_get_next_queued_message() - called by driver to check for queued
1297  * messages
1298  * @master: the master to check for queued messages
1299  *
1300  * If there are more messages in the queue, the next message is returned from
1301  * this call.
1302  *
1303  * Return: the next message in the queue, else NULL if the queue is empty.
1304  */
1305 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1306 {
1307         struct spi_message *next;
1308         unsigned long flags;
1309
1310         /* get a pointer to the next message, if any */
1311         spin_lock_irqsave(&master->queue_lock, flags);
1312         next = list_first_entry_or_null(&master->queue, struct spi_message,
1313                                         queue);
1314         spin_unlock_irqrestore(&master->queue_lock, flags);
1315
1316         return next;
1317 }
1318 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1319
1320 /**
1321  * spi_finalize_current_message() - the current message is complete
1322  * @master: the master to return the message to
1323  *
1324  * Called by the driver to notify the core that the message in the front of the
1325  * queue is complete and can be removed from the queue.
1326  */
1327 void spi_finalize_current_message(struct spi_master *master)
1328 {
1329         struct spi_message *mesg;
1330         unsigned long flags;
1331         int ret;
1332
1333         spin_lock_irqsave(&master->queue_lock, flags);
1334         mesg = master->cur_msg;
1335         spin_unlock_irqrestore(&master->queue_lock, flags);
1336
1337         spi_unmap_msg(master, mesg);
1338
1339         if (master->cur_msg_prepared && master->unprepare_message) {
1340                 ret = master->unprepare_message(master, mesg);
1341                 if (ret) {
1342                         dev_err(&master->dev,
1343                                 "failed to unprepare message: %d\n", ret);
1344                 }
1345         }
1346
1347         spin_lock_irqsave(&master->queue_lock, flags);
1348         master->cur_msg = NULL;
1349         master->cur_msg_prepared = false;
1350         kthread_queue_work(&master->kworker, &master->pump_messages);
1351         spin_unlock_irqrestore(&master->queue_lock, flags);
1352
1353         trace_spi_message_done(mesg);
1354
1355         mesg->state = NULL;
1356         if (mesg->complete)
1357                 mesg->complete(mesg->context);
1358 }
1359 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1360
1361 static int spi_start_queue(struct spi_master *master)
1362 {
1363         unsigned long flags;
1364
1365         spin_lock_irqsave(&master->queue_lock, flags);
1366
1367         if (master->running || master->busy) {
1368                 spin_unlock_irqrestore(&master->queue_lock, flags);
1369                 return -EBUSY;
1370         }
1371
1372         master->running = true;
1373         master->cur_msg = NULL;
1374         spin_unlock_irqrestore(&master->queue_lock, flags);
1375
1376         kthread_queue_work(&master->kworker, &master->pump_messages);
1377
1378         return 0;
1379 }
1380
1381 static int spi_stop_queue(struct spi_master *master)
1382 {
1383         unsigned long flags;
1384         unsigned limit = 500;
1385         int ret = 0;
1386
1387         spin_lock_irqsave(&master->queue_lock, flags);
1388
1389         /*
1390          * This is a bit lame, but is optimized for the common execution path.
1391          * A wait_queue on the master->busy could be used, but then the common
1392          * execution path (pump_messages) would be required to call wake_up or
1393          * friends on every SPI message. Do this instead.
1394          */
1395         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1396                 spin_unlock_irqrestore(&master->queue_lock, flags);
1397                 usleep_range(10000, 11000);
1398                 spin_lock_irqsave(&master->queue_lock, flags);
1399         }
1400
1401         if (!list_empty(&master->queue) || master->busy)
1402                 ret = -EBUSY;
1403         else
1404                 master->running = false;
1405
1406         spin_unlock_irqrestore(&master->queue_lock, flags);
1407
1408         if (ret) {
1409                 dev_warn(&master->dev,
1410                          "could not stop message queue\n");
1411                 return ret;
1412         }
1413         return ret;
1414 }
1415
1416 static int spi_destroy_queue(struct spi_master *master)
1417 {
1418         int ret;
1419
1420         ret = spi_stop_queue(master);
1421
1422         /*
1423          * kthread_flush_worker will block until all work is done.
1424          * If the reason that stop_queue timed out is that the work will never
1425          * finish, then it does no good to call flush/stop thread, so
1426          * return anyway.
1427          */
1428         if (ret) {
1429                 dev_err(&master->dev, "problem destroying queue\n");
1430                 return ret;
1431         }
1432
1433         kthread_flush_worker(&master->kworker);
1434         kthread_stop(master->kworker_task);
1435
1436         return 0;
1437 }
1438
1439 static int __spi_queued_transfer(struct spi_device *spi,
1440                                  struct spi_message *msg,
1441                                  bool need_pump)
1442 {
1443         struct spi_master *master = spi->master;
1444         unsigned long flags;
1445
1446         spin_lock_irqsave(&master->queue_lock, flags);
1447
1448         if (!master->running) {
1449                 spin_unlock_irqrestore(&master->queue_lock, flags);
1450                 return -ESHUTDOWN;
1451         }
1452         msg->actual_length = 0;
1453         msg->status = -EINPROGRESS;
1454
1455         list_add_tail(&msg->queue, &master->queue);
1456         if (!master->busy && need_pump)
1457                 kthread_queue_work(&master->kworker, &master->pump_messages);
1458
1459         spin_unlock_irqrestore(&master->queue_lock, flags);
1460         return 0;
1461 }
1462
1463 /**
1464  * spi_queued_transfer - transfer function for queued transfers
1465  * @spi: spi device which is requesting transfer
1466  * @msg: spi message which is to handled is queued to driver queue
1467  *
1468  * Return: zero on success, else a negative error code.
1469  */
1470 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1471 {
1472         return __spi_queued_transfer(spi, msg, true);
1473 }
1474
1475 static int spi_master_initialize_queue(struct spi_master *master)
1476 {
1477         int ret;
1478
1479         master->transfer = spi_queued_transfer;
1480         if (!master->transfer_one_message)
1481                 master->transfer_one_message = spi_transfer_one_message;
1482
1483         /* Initialize and start queue */
1484         ret = spi_init_queue(master);
1485         if (ret) {
1486                 dev_err(&master->dev, "problem initializing queue\n");
1487                 goto err_init_queue;
1488         }
1489         master->queued = true;
1490         ret = spi_start_queue(master);
1491         if (ret) {
1492                 dev_err(&master->dev, "problem starting queue\n");
1493                 goto err_start_queue;
1494         }
1495
1496         return 0;
1497
1498 err_start_queue:
1499         spi_destroy_queue(master);
1500 err_init_queue:
1501         return ret;
1502 }
1503
1504 /*-------------------------------------------------------------------------*/
1505
1506 #if defined(CONFIG_OF)
1507 static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi,
1508                            struct device_node *nc)
1509 {
1510         u32 value;
1511         int rc;
1512
1513         /* Device address */
1514         rc = of_property_read_u32(nc, "reg", &value);
1515         if (rc) {
1516                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1517                         nc->full_name, rc);
1518                 return rc;
1519         }
1520         spi->chip_select = value;
1521
1522         /* Mode (clock phase/polarity/etc.) */
1523         if (of_find_property(nc, "spi-cpha", NULL))
1524                 spi->mode |= SPI_CPHA;
1525         if (of_find_property(nc, "spi-cpol", NULL))
1526                 spi->mode |= SPI_CPOL;
1527         if (of_find_property(nc, "spi-cs-high", NULL))
1528                 spi->mode |= SPI_CS_HIGH;
1529         if (of_find_property(nc, "spi-3wire", NULL))
1530                 spi->mode |= SPI_3WIRE;
1531         if (of_find_property(nc, "spi-lsb-first", NULL))
1532                 spi->mode |= SPI_LSB_FIRST;
1533
1534         /* Device DUAL/QUAD mode */
1535         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1536                 switch (value) {
1537                 case 1:
1538                         break;
1539                 case 2:
1540                         spi->mode |= SPI_TX_DUAL;
1541                         break;
1542                 case 4:
1543                         spi->mode |= SPI_TX_QUAD;
1544                         break;
1545                 default:
1546                         dev_warn(&master->dev,
1547                                 "spi-tx-bus-width %d not supported\n",
1548                                 value);
1549                         break;
1550                 }
1551         }
1552
1553         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1554                 switch (value) {
1555                 case 1:
1556                         break;
1557                 case 2:
1558                         spi->mode |= SPI_RX_DUAL;
1559                         break;
1560                 case 4:
1561                         spi->mode |= SPI_RX_QUAD;
1562                         break;
1563                 default:
1564                         dev_warn(&master->dev,
1565                                 "spi-rx-bus-width %d not supported\n",
1566                                 value);
1567                         break;
1568                 }
1569         }
1570
1571         /* Device speed */
1572         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1573         if (rc) {
1574                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1575                         nc->full_name, rc);
1576                 return rc;
1577         }
1578         spi->max_speed_hz = value;
1579
1580         return 0;
1581 }
1582
1583 static struct spi_device *
1584 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1585 {
1586         struct spi_device *spi;
1587         int rc;
1588
1589         /* Alloc an spi_device */
1590         spi = spi_alloc_device(master);
1591         if (!spi) {
1592                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1593                         nc->full_name);
1594                 rc = -ENOMEM;
1595                 goto err_out;
1596         }
1597
1598         /* Select device driver */
1599         rc = of_modalias_node(nc, spi->modalias,
1600                                 sizeof(spi->modalias));
1601         if (rc < 0) {
1602                 dev_err(&master->dev, "cannot find modalias for %s\n",
1603                         nc->full_name);
1604                 goto err_out;
1605         }
1606
1607         rc = of_spi_parse_dt(master, spi, nc);
1608         if (rc)
1609                 goto err_out;
1610
1611         /* Store a pointer to the node in the device structure */
1612         of_node_get(nc);
1613         spi->dev.of_node = nc;
1614
1615         /* Register the new device */
1616         rc = spi_add_device(spi);
1617         if (rc) {
1618                 dev_err(&master->dev, "spi_device register error %s\n",
1619                         nc->full_name);
1620                 goto err_of_node_put;
1621         }
1622
1623         return spi;
1624
1625 err_of_node_put:
1626         of_node_put(nc);
1627 err_out:
1628         spi_dev_put(spi);
1629         return ERR_PTR(rc);
1630 }
1631
1632 /**
1633  * of_register_spi_devices() - Register child devices onto the SPI bus
1634  * @master:     Pointer to spi_master device
1635  *
1636  * Registers an spi_device for each child node of master node which has a 'reg'
1637  * property.
1638  */
1639 static void of_register_spi_devices(struct spi_master *master)
1640 {
1641         struct spi_device *spi;
1642         struct device_node *nc;
1643
1644         if (!master->dev.of_node)
1645                 return;
1646
1647         for_each_available_child_of_node(master->dev.of_node, nc) {
1648                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1649                         continue;
1650                 spi = of_register_spi_device(master, nc);
1651                 if (IS_ERR(spi)) {
1652                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1653                                 nc->full_name);
1654                         of_node_clear_flag(nc, OF_POPULATED);
1655                 }
1656         }
1657 }
1658 #else
1659 static void of_register_spi_devices(struct spi_master *master) { }
1660 #endif
1661
1662 #ifdef CONFIG_ACPI
1663 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1664 {
1665         struct spi_device *spi = data;
1666         struct spi_master *master = spi->master;
1667
1668         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1669                 struct acpi_resource_spi_serialbus *sb;
1670
1671                 sb = &ares->data.spi_serial_bus;
1672                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1673                         /*
1674                          * ACPI DeviceSelection numbering is handled by the
1675                          * host controller driver in Windows and can vary
1676                          * from driver to driver. In Linux we always expect
1677                          * 0 .. max - 1 so we need to ask the driver to
1678                          * translate between the two schemes.
1679                          */
1680                         if (master->fw_translate_cs) {
1681                                 int cs = master->fw_translate_cs(master,
1682                                                 sb->device_selection);
1683                                 if (cs < 0)
1684                                         return cs;
1685                                 spi->chip_select = cs;
1686                         } else {
1687                                 spi->chip_select = sb->device_selection;
1688                         }
1689
1690                         spi->max_speed_hz = sb->connection_speed;
1691
1692                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1693                                 spi->mode |= SPI_CPHA;
1694                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1695                                 spi->mode |= SPI_CPOL;
1696                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1697                                 spi->mode |= SPI_CS_HIGH;
1698                 }
1699         } else if (spi->irq < 0) {
1700                 struct resource r;
1701
1702                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1703                         spi->irq = r.start;
1704         }
1705
1706         /* Always tell the ACPI core to skip this resource */
1707         return 1;
1708 }
1709
1710 static acpi_status acpi_register_spi_device(struct spi_master *master,
1711                                             struct acpi_device *adev)
1712 {
1713         struct list_head resource_list;
1714         struct spi_device *spi;
1715         int ret;
1716
1717         if (acpi_bus_get_status(adev) || !adev->status.present ||
1718             acpi_device_enumerated(adev))
1719                 return AE_OK;
1720
1721         spi = spi_alloc_device(master);
1722         if (!spi) {
1723                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1724                         dev_name(&adev->dev));
1725                 return AE_NO_MEMORY;
1726         }
1727
1728         ACPI_COMPANION_SET(&spi->dev, adev);
1729         spi->irq = -1;
1730
1731         INIT_LIST_HEAD(&resource_list);
1732         ret = acpi_dev_get_resources(adev, &resource_list,
1733                                      acpi_spi_add_resource, spi);
1734         acpi_dev_free_resource_list(&resource_list);
1735
1736         if (ret < 0 || !spi->max_speed_hz) {
1737                 spi_dev_put(spi);
1738                 return AE_OK;
1739         }
1740
1741         if (spi->irq < 0)
1742                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1743
1744         acpi_device_set_enumerated(adev);
1745
1746         adev->power.flags.ignore_parent = true;
1747         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1748         if (spi_add_device(spi)) {
1749                 adev->power.flags.ignore_parent = false;
1750                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1751                         dev_name(&adev->dev));
1752                 spi_dev_put(spi);
1753         }
1754
1755         return AE_OK;
1756 }
1757
1758 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1759                                        void *data, void **return_value)
1760 {
1761         struct spi_master *master = data;
1762         struct acpi_device *adev;
1763
1764         if (acpi_bus_get_device(handle, &adev))
1765                 return AE_OK;
1766
1767         return acpi_register_spi_device(master, adev);
1768 }
1769
1770 static void acpi_register_spi_devices(struct spi_master *master)
1771 {
1772         acpi_status status;
1773         acpi_handle handle;
1774
1775         handle = ACPI_HANDLE(master->dev.parent);
1776         if (!handle)
1777                 return;
1778
1779         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1780                                      acpi_spi_add_device, NULL,
1781                                      master, NULL);
1782         if (ACPI_FAILURE(status))
1783                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1784 }
1785 #else
1786 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1787 #endif /* CONFIG_ACPI */
1788
1789 static void spi_master_release(struct device *dev)
1790 {
1791         struct spi_master *master;
1792
1793         master = container_of(dev, struct spi_master, dev);
1794         kfree(master);
1795 }
1796
1797 static struct class spi_master_class = {
1798         .name           = "spi_master",
1799         .owner          = THIS_MODULE,
1800         .dev_release    = spi_master_release,
1801         .dev_groups     = spi_master_groups,
1802 };
1803
1804
1805 /**
1806  * spi_alloc_master - allocate SPI master controller
1807  * @dev: the controller, possibly using the platform_bus
1808  * @size: how much zeroed driver-private data to allocate; the pointer to this
1809  *      memory is in the driver_data field of the returned device,
1810  *      accessible with spi_master_get_devdata().
1811  * Context: can sleep
1812  *
1813  * This call is used only by SPI master controller drivers, which are the
1814  * only ones directly touching chip registers.  It's how they allocate
1815  * an spi_master structure, prior to calling spi_register_master().
1816  *
1817  * This must be called from context that can sleep.
1818  *
1819  * The caller is responsible for assigning the bus number and initializing
1820  * the master's methods before calling spi_register_master(); and (after errors
1821  * adding the device) calling spi_master_put() to prevent a memory leak.
1822  *
1823  * Return: the SPI master structure on success, else NULL.
1824  */
1825 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1826 {
1827         struct spi_master       *master;
1828
1829         if (!dev)
1830                 return NULL;
1831
1832         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1833         if (!master)
1834                 return NULL;
1835
1836         device_initialize(&master->dev);
1837         master->bus_num = -1;
1838         master->num_chipselect = 1;
1839         master->dev.class = &spi_master_class;
1840         master->dev.parent = dev;
1841         pm_suspend_ignore_children(&master->dev, true);
1842         spi_master_set_devdata(master, &master[1]);
1843
1844         return master;
1845 }
1846 EXPORT_SYMBOL_GPL(spi_alloc_master);
1847
1848 #ifdef CONFIG_OF
1849 static int of_spi_register_master(struct spi_master *master)
1850 {
1851         int nb, i, *cs;
1852         struct device_node *np = master->dev.of_node;
1853
1854         if (!np)
1855                 return 0;
1856
1857         nb = of_gpio_named_count(np, "cs-gpios");
1858         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1859
1860         /* Return error only for an incorrectly formed cs-gpios property */
1861         if (nb == 0 || nb == -ENOENT)
1862                 return 0;
1863         else if (nb < 0)
1864                 return nb;
1865
1866         cs = devm_kzalloc(&master->dev,
1867                           sizeof(int) * master->num_chipselect,
1868                           GFP_KERNEL);
1869         master->cs_gpios = cs;
1870
1871         if (!master->cs_gpios)
1872                 return -ENOMEM;
1873
1874         for (i = 0; i < master->num_chipselect; i++)
1875                 cs[i] = -ENOENT;
1876
1877         for (i = 0; i < nb; i++)
1878                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1879
1880         return 0;
1881 }
1882 #else
1883 static int of_spi_register_master(struct spi_master *master)
1884 {
1885         return 0;
1886 }
1887 #endif
1888
1889 /**
1890  * spi_register_master - register SPI master controller
1891  * @master: initialized master, originally from spi_alloc_master()
1892  * Context: can sleep
1893  *
1894  * SPI master controllers connect to their drivers using some non-SPI bus,
1895  * such as the platform bus.  The final stage of probe() in that code
1896  * includes calling spi_register_master() to hook up to this SPI bus glue.
1897  *
1898  * SPI controllers use board specific (often SOC specific) bus numbers,
1899  * and board-specific addressing for SPI devices combines those numbers
1900  * with chip select numbers.  Since SPI does not directly support dynamic
1901  * device identification, boards need configuration tables telling which
1902  * chip is at which address.
1903  *
1904  * This must be called from context that can sleep.  It returns zero on
1905  * success, else a negative error code (dropping the master's refcount).
1906  * After a successful return, the caller is responsible for calling
1907  * spi_unregister_master().
1908  *
1909  * Return: zero on success, else a negative error code.
1910  */
1911 int spi_register_master(struct spi_master *master)
1912 {
1913         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1914         struct device           *dev = master->dev.parent;
1915         struct boardinfo        *bi;
1916         int                     status = -ENODEV;
1917         int                     dynamic = 0;
1918
1919         if (!dev)
1920                 return -ENODEV;
1921
1922         status = of_spi_register_master(master);
1923         if (status)
1924                 return status;
1925
1926         /* even if it's just one always-selected device, there must
1927          * be at least one chipselect
1928          */
1929         if (master->num_chipselect == 0)
1930                 return -EINVAL;
1931
1932         if ((master->bus_num < 0) && master->dev.of_node)
1933                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1934
1935         /* convention:  dynamically assigned bus IDs count down from the max */
1936         if (master->bus_num < 0) {
1937                 /* FIXME switch to an IDR based scheme, something like
1938                  * I2C now uses, so we can't run out of "dynamic" IDs
1939                  */
1940                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1941                 dynamic = 1;
1942         }
1943
1944         INIT_LIST_HEAD(&master->queue);
1945         spin_lock_init(&master->queue_lock);
1946         spin_lock_init(&master->bus_lock_spinlock);
1947         mutex_init(&master->bus_lock_mutex);
1948         mutex_init(&master->io_mutex);
1949         master->bus_lock_flag = 0;
1950         init_completion(&master->xfer_completion);
1951         if (!master->max_dma_len)
1952                 master->max_dma_len = INT_MAX;
1953
1954         /* register the device, then userspace will see it.
1955          * registration fails if the bus ID is in use.
1956          */
1957         dev_set_name(&master->dev, "spi%u", master->bus_num);
1958         status = device_add(&master->dev);
1959         if (status < 0)
1960                 goto done;
1961         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1962                         dynamic ? " (dynamic)" : "");
1963
1964         /* If we're using a queued driver, start the queue */
1965         if (master->transfer)
1966                 dev_info(dev, "master is unqueued, this is deprecated\n");
1967         else {
1968                 status = spi_master_initialize_queue(master);
1969                 if (status) {
1970                         device_del(&master->dev);
1971                         goto done;
1972                 }
1973         }
1974         /* add statistics */
1975         spin_lock_init(&master->statistics.lock);
1976
1977         mutex_lock(&board_lock);
1978         list_add_tail(&master->list, &spi_master_list);
1979         list_for_each_entry(bi, &board_list, list)
1980                 spi_match_master_to_boardinfo(master, &bi->board_info);
1981         mutex_unlock(&board_lock);
1982
1983         /* Register devices from the device tree and ACPI */
1984         of_register_spi_devices(master);
1985         acpi_register_spi_devices(master);
1986 done:
1987         return status;
1988 }
1989 EXPORT_SYMBOL_GPL(spi_register_master);
1990
1991 static void devm_spi_unregister(struct device *dev, void *res)
1992 {
1993         spi_unregister_master(*(struct spi_master **)res);
1994 }
1995
1996 /**
1997  * dev_spi_register_master - register managed SPI master controller
1998  * @dev:    device managing SPI master
1999  * @master: initialized master, originally from spi_alloc_master()
2000  * Context: can sleep
2001  *
2002  * Register a SPI device as with spi_register_master() which will
2003  * automatically be unregister
2004  *
2005  * Return: zero on success, else a negative error code.
2006  */
2007 int devm_spi_register_master(struct device *dev, struct spi_master *master)
2008 {
2009         struct spi_master **ptr;
2010         int ret;
2011
2012         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2013         if (!ptr)
2014                 return -ENOMEM;
2015
2016         ret = spi_register_master(master);
2017         if (!ret) {
2018                 *ptr = master;
2019                 devres_add(dev, ptr);
2020         } else {
2021                 devres_free(ptr);
2022         }
2023
2024         return ret;
2025 }
2026 EXPORT_SYMBOL_GPL(devm_spi_register_master);
2027
2028 static int __unregister(struct device *dev, void *null)
2029 {
2030         spi_unregister_device(to_spi_device(dev));
2031         return 0;
2032 }
2033
2034 /**
2035  * spi_unregister_master - unregister SPI master controller
2036  * @master: the master being unregistered
2037  * Context: can sleep
2038  *
2039  * This call is used only by SPI master controller drivers, which are the
2040  * only ones directly touching chip registers.
2041  *
2042  * This must be called from context that can sleep.
2043  */
2044 void spi_unregister_master(struct spi_master *master)
2045 {
2046         int dummy;
2047
2048         if (master->queued) {
2049                 if (spi_destroy_queue(master))
2050                         dev_err(&master->dev, "queue remove failed\n");
2051         }
2052
2053         mutex_lock(&board_lock);
2054         list_del(&master->list);
2055         mutex_unlock(&board_lock);
2056
2057         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2058         device_unregister(&master->dev);
2059 }
2060 EXPORT_SYMBOL_GPL(spi_unregister_master);
2061
2062 int spi_master_suspend(struct spi_master *master)
2063 {
2064         int ret;
2065
2066         /* Basically no-ops for non-queued masters */
2067         if (!master->queued)
2068                 return 0;
2069
2070         ret = spi_stop_queue(master);
2071         if (ret)
2072                 dev_err(&master->dev, "queue stop failed\n");
2073
2074         return ret;
2075 }
2076 EXPORT_SYMBOL_GPL(spi_master_suspend);
2077
2078 int spi_master_resume(struct spi_master *master)
2079 {
2080         int ret;
2081
2082         if (!master->queued)
2083                 return 0;
2084
2085         ret = spi_start_queue(master);
2086         if (ret)
2087                 dev_err(&master->dev, "queue restart failed\n");
2088
2089         return ret;
2090 }
2091 EXPORT_SYMBOL_GPL(spi_master_resume);
2092
2093 static int __spi_master_match(struct device *dev, const void *data)
2094 {
2095         struct spi_master *m;
2096         const u16 *bus_num = data;
2097
2098         m = container_of(dev, struct spi_master, dev);
2099         return m->bus_num == *bus_num;
2100 }
2101
2102 /**
2103  * spi_busnum_to_master - look up master associated with bus_num
2104  * @bus_num: the master's bus number
2105  * Context: can sleep
2106  *
2107  * This call may be used with devices that are registered after
2108  * arch init time.  It returns a refcounted pointer to the relevant
2109  * spi_master (which the caller must release), or NULL if there is
2110  * no such master registered.
2111  *
2112  * Return: the SPI master structure on success, else NULL.
2113  */
2114 struct spi_master *spi_busnum_to_master(u16 bus_num)
2115 {
2116         struct device           *dev;
2117         struct spi_master       *master = NULL;
2118
2119         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2120                                 __spi_master_match);
2121         if (dev)
2122                 master = container_of(dev, struct spi_master, dev);
2123         /* reference got in class_find_device */
2124         return master;
2125 }
2126 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2127
2128 /*-------------------------------------------------------------------------*/
2129
2130 /* Core methods for SPI resource management */
2131
2132 /**
2133  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2134  *                 during the processing of a spi_message while using
2135  *                 spi_transfer_one
2136  * @spi:     the spi device for which we allocate memory
2137  * @release: the release code to execute for this resource
2138  * @size:    size to alloc and return
2139  * @gfp:     GFP allocation flags
2140  *
2141  * Return: the pointer to the allocated data
2142  *
2143  * This may get enhanced in the future to allocate from a memory pool
2144  * of the @spi_device or @spi_master to avoid repeated allocations.
2145  */
2146 void *spi_res_alloc(struct spi_device *spi,
2147                     spi_res_release_t release,
2148                     size_t size, gfp_t gfp)
2149 {
2150         struct spi_res *sres;
2151
2152         sres = kzalloc(sizeof(*sres) + size, gfp);
2153         if (!sres)
2154                 return NULL;
2155
2156         INIT_LIST_HEAD(&sres->entry);
2157         sres->release = release;
2158
2159         return sres->data;
2160 }
2161 EXPORT_SYMBOL_GPL(spi_res_alloc);
2162
2163 /**
2164  * spi_res_free - free an spi resource
2165  * @res: pointer to the custom data of a resource
2166  *
2167  */
2168 void spi_res_free(void *res)
2169 {
2170         struct spi_res *sres = container_of(res, struct spi_res, data);
2171
2172         if (!res)
2173                 return;
2174
2175         WARN_ON(!list_empty(&sres->entry));
2176         kfree(sres);
2177 }
2178 EXPORT_SYMBOL_GPL(spi_res_free);
2179
2180 /**
2181  * spi_res_add - add a spi_res to the spi_message
2182  * @message: the spi message
2183  * @res:     the spi_resource
2184  */
2185 void spi_res_add(struct spi_message *message, void *res)
2186 {
2187         struct spi_res *sres = container_of(res, struct spi_res, data);
2188
2189         WARN_ON(!list_empty(&sres->entry));
2190         list_add_tail(&sres->entry, &message->resources);
2191 }
2192 EXPORT_SYMBOL_GPL(spi_res_add);
2193
2194 /**
2195  * spi_res_release - release all spi resources for this message
2196  * @master:  the @spi_master
2197  * @message: the @spi_message
2198  */
2199 void spi_res_release(struct spi_master *master,
2200                      struct spi_message *message)
2201 {
2202         struct spi_res *res;
2203
2204         while (!list_empty(&message->resources)) {
2205                 res = list_last_entry(&message->resources,
2206                                       struct spi_res, entry);
2207
2208                 if (res->release)
2209                         res->release(master, message, res->data);
2210
2211                 list_del(&res->entry);
2212
2213                 kfree(res);
2214         }
2215 }
2216 EXPORT_SYMBOL_GPL(spi_res_release);
2217
2218 /*-------------------------------------------------------------------------*/
2219
2220 /* Core methods for spi_message alterations */
2221
2222 static void __spi_replace_transfers_release(struct spi_master *master,
2223                                             struct spi_message *msg,
2224                                             void *res)
2225 {
2226         struct spi_replaced_transfers *rxfer = res;
2227         size_t i;
2228
2229         /* call extra callback if requested */
2230         if (rxfer->release)
2231                 rxfer->release(master, msg, res);
2232
2233         /* insert replaced transfers back into the message */
2234         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2235
2236         /* remove the formerly inserted entries */
2237         for (i = 0; i < rxfer->inserted; i++)
2238                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2239 }
2240
2241 /**
2242  * spi_replace_transfers - replace transfers with several transfers
2243  *                         and register change with spi_message.resources
2244  * @msg:           the spi_message we work upon
2245  * @xfer_first:    the first spi_transfer we want to replace
2246  * @remove:        number of transfers to remove
2247  * @insert:        the number of transfers we want to insert instead
2248  * @release:       extra release code necessary in some circumstances
2249  * @extradatasize: extra data to allocate (with alignment guarantees
2250  *                 of struct @spi_transfer)
2251  * @gfp:           gfp flags
2252  *
2253  * Returns: pointer to @spi_replaced_transfers,
2254  *          PTR_ERR(...) in case of errors.
2255  */
2256 struct spi_replaced_transfers *spi_replace_transfers(
2257         struct spi_message *msg,
2258         struct spi_transfer *xfer_first,
2259         size_t remove,
2260         size_t insert,
2261         spi_replaced_release_t release,
2262         size_t extradatasize,
2263         gfp_t gfp)
2264 {
2265         struct spi_replaced_transfers *rxfer;
2266         struct spi_transfer *xfer;
2267         size_t i;
2268
2269         /* allocate the structure using spi_res */
2270         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2271                               insert * sizeof(struct spi_transfer)
2272                               + sizeof(struct spi_replaced_transfers)
2273                               + extradatasize,
2274                               gfp);
2275         if (!rxfer)
2276                 return ERR_PTR(-ENOMEM);
2277
2278         /* the release code to invoke before running the generic release */
2279         rxfer->release = release;
2280
2281         /* assign extradata */
2282         if (extradatasize)
2283                 rxfer->extradata =
2284                         &rxfer->inserted_transfers[insert];
2285
2286         /* init the replaced_transfers list */
2287         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2288
2289         /* assign the list_entry after which we should reinsert
2290          * the @replaced_transfers - it may be spi_message.messages!
2291          */
2292         rxfer->replaced_after = xfer_first->transfer_list.prev;
2293
2294         /* remove the requested number of transfers */
2295         for (i = 0; i < remove; i++) {
2296                 /* if the entry after replaced_after it is msg->transfers
2297                  * then we have been requested to remove more transfers
2298                  * than are in the list
2299                  */
2300                 if (rxfer->replaced_after->next == &msg->transfers) {
2301                         dev_err(&msg->spi->dev,
2302                                 "requested to remove more spi_transfers than are available\n");
2303                         /* insert replaced transfers back into the message */
2304                         list_splice(&rxfer->replaced_transfers,
2305                                     rxfer->replaced_after);
2306
2307                         /* free the spi_replace_transfer structure */
2308                         spi_res_free(rxfer);
2309
2310                         /* and return with an error */
2311                         return ERR_PTR(-EINVAL);
2312                 }
2313
2314                 /* remove the entry after replaced_after from list of
2315                  * transfers and add it to list of replaced_transfers
2316                  */
2317                 list_move_tail(rxfer->replaced_after->next,
2318                                &rxfer->replaced_transfers);
2319         }
2320
2321         /* create copy of the given xfer with identical settings
2322          * based on the first transfer to get removed
2323          */
2324         for (i = 0; i < insert; i++) {
2325                 /* we need to run in reverse order */
2326                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2327
2328                 /* copy all spi_transfer data */
2329                 memcpy(xfer, xfer_first, sizeof(*xfer));
2330
2331                 /* add to list */
2332                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2333
2334                 /* clear cs_change and delay_usecs for all but the last */
2335                 if (i) {
2336                         xfer->cs_change = false;
2337                         xfer->delay_usecs = 0;
2338                 }
2339         }
2340
2341         /* set up inserted */
2342         rxfer->inserted = insert;
2343
2344         /* and register it with spi_res/spi_message */
2345         spi_res_add(msg, rxfer);
2346
2347         return rxfer;
2348 }
2349 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2350
2351 static int __spi_split_transfer_maxsize(struct spi_master *master,
2352                                         struct spi_message *msg,
2353                                         struct spi_transfer **xferp,
2354                                         size_t maxsize,
2355                                         gfp_t gfp)
2356 {
2357         struct spi_transfer *xfer = *xferp, *xfers;
2358         struct spi_replaced_transfers *srt;
2359         size_t offset;
2360         size_t count, i;
2361
2362         /* warn once about this fact that we are splitting a transfer */
2363         dev_warn_once(&msg->spi->dev,
2364                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2365                       xfer->len, maxsize);
2366
2367         /* calculate how many we have to replace */
2368         count = DIV_ROUND_UP(xfer->len, maxsize);
2369
2370         /* create replacement */
2371         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2372         if (IS_ERR(srt))
2373                 return PTR_ERR(srt);
2374         xfers = srt->inserted_transfers;
2375
2376         /* now handle each of those newly inserted spi_transfers
2377          * note that the replacements spi_transfers all are preset
2378          * to the same values as *xferp, so tx_buf, rx_buf and len
2379          * are all identical (as well as most others)
2380          * so we just have to fix up len and the pointers.
2381          *
2382          * this also includes support for the depreciated
2383          * spi_message.is_dma_mapped interface
2384          */
2385
2386         /* the first transfer just needs the length modified, so we
2387          * run it outside the loop
2388          */
2389         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2390
2391         /* all the others need rx_buf/tx_buf also set */
2392         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2393                 /* update rx_buf, tx_buf and dma */
2394                 if (xfers[i].rx_buf)
2395                         xfers[i].rx_buf += offset;
2396                 if (xfers[i].rx_dma)
2397                         xfers[i].rx_dma += offset;
2398                 if (xfers[i].tx_buf)
2399                         xfers[i].tx_buf += offset;
2400                 if (xfers[i].tx_dma)
2401                         xfers[i].tx_dma += offset;
2402
2403                 /* update length */
2404                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2405         }
2406
2407         /* we set up xferp to the last entry we have inserted,
2408          * so that we skip those already split transfers
2409          */
2410         *xferp = &xfers[count - 1];
2411
2412         /* increment statistics counters */
2413         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2414                                        transfers_split_maxsize);
2415         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2416                                        transfers_split_maxsize);
2417
2418         return 0;
2419 }
2420
2421 /**
2422  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2423  *                              when an individual transfer exceeds a
2424  *                              certain size
2425  * @master:    the @spi_master for this transfer
2426  * @msg:   the @spi_message to transform
2427  * @maxsize:  the maximum when to apply this
2428  * @gfp: GFP allocation flags
2429  *
2430  * Return: status of transformation
2431  */
2432 int spi_split_transfers_maxsize(struct spi_master *master,
2433                                 struct spi_message *msg,
2434                                 size_t maxsize,
2435                                 gfp_t gfp)
2436 {
2437         struct spi_transfer *xfer;
2438         int ret;
2439
2440         /* iterate over the transfer_list,
2441          * but note that xfer is advanced to the last transfer inserted
2442          * to avoid checking sizes again unnecessarily (also xfer does
2443          * potentiall belong to a different list by the time the
2444          * replacement has happened
2445          */
2446         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2447                 if (xfer->len > maxsize) {
2448                         ret = __spi_split_transfer_maxsize(
2449                                 master, msg, &xfer, maxsize, gfp);
2450                         if (ret)
2451                                 return ret;
2452                 }
2453         }
2454
2455         return 0;
2456 }
2457 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2458
2459 /*-------------------------------------------------------------------------*/
2460
2461 /* Core methods for SPI master protocol drivers.  Some of the
2462  * other core methods are currently defined as inline functions.
2463  */
2464
2465 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2466 {
2467         if (master->bits_per_word_mask) {
2468                 /* Only 32 bits fit in the mask */
2469                 if (bits_per_word > 32)
2470                         return -EINVAL;
2471                 if (!(master->bits_per_word_mask &
2472                                 SPI_BPW_MASK(bits_per_word)))
2473                         return -EINVAL;
2474         }
2475
2476         return 0;
2477 }
2478
2479 /**
2480  * spi_setup - setup SPI mode and clock rate
2481  * @spi: the device whose settings are being modified
2482  * Context: can sleep, and no requests are queued to the device
2483  *
2484  * SPI protocol drivers may need to update the transfer mode if the
2485  * device doesn't work with its default.  They may likewise need
2486  * to update clock rates or word sizes from initial values.  This function
2487  * changes those settings, and must be called from a context that can sleep.
2488  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2489  * effect the next time the device is selected and data is transferred to
2490  * or from it.  When this function returns, the spi device is deselected.
2491  *
2492  * Note that this call will fail if the protocol driver specifies an option
2493  * that the underlying controller or its driver does not support.  For
2494  * example, not all hardware supports wire transfers using nine bit words,
2495  * LSB-first wire encoding, or active-high chipselects.
2496  *
2497  * Return: zero on success, else a negative error code.
2498  */
2499 int spi_setup(struct spi_device *spi)
2500 {
2501         unsigned        bad_bits, ugly_bits;
2502         int             status;
2503
2504         /* check mode to prevent that DUAL and QUAD set at the same time
2505          */
2506         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2507                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2508                 dev_err(&spi->dev,
2509                 "setup: can not select dual and quad at the same time\n");
2510                 return -EINVAL;
2511         }
2512         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2513          */
2514         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2515                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2516                 return -EINVAL;
2517         /* help drivers fail *cleanly* when they need options
2518          * that aren't supported with their current master
2519          */
2520         bad_bits = spi->mode & ~spi->master->mode_bits;
2521         ugly_bits = bad_bits &
2522                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2523         if (ugly_bits) {
2524                 dev_warn(&spi->dev,
2525                          "setup: ignoring unsupported mode bits %x\n",
2526                          ugly_bits);
2527                 spi->mode &= ~ugly_bits;
2528                 bad_bits &= ~ugly_bits;
2529         }
2530         if (bad_bits) {
2531                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2532                         bad_bits);
2533                 return -EINVAL;
2534         }
2535
2536         if (!spi->bits_per_word)
2537                 spi->bits_per_word = 8;
2538
2539         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2540         if (status)
2541                 return status;
2542
2543         if (!spi->max_speed_hz)
2544                 spi->max_speed_hz = spi->master->max_speed_hz;
2545
2546         if (spi->master->setup)
2547                 status = spi->master->setup(spi);
2548
2549         spi_set_cs(spi, false);
2550
2551         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2552                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2553                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2554                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2555                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2556                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2557                         spi->bits_per_word, spi->max_speed_hz,
2558                         status);
2559
2560         return status;
2561 }
2562 EXPORT_SYMBOL_GPL(spi_setup);
2563
2564 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2565 {
2566         struct spi_master *master = spi->master;
2567         struct spi_transfer *xfer;
2568         int w_size;
2569
2570         if (list_empty(&message->transfers))
2571                 return -EINVAL;
2572
2573         /* Half-duplex links include original MicroWire, and ones with
2574          * only one data pin like SPI_3WIRE (switches direction) or where
2575          * either MOSI or MISO is missing.  They can also be caused by
2576          * software limitations.
2577          */
2578         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2579                         || (spi->mode & SPI_3WIRE)) {
2580                 unsigned flags = master->flags;
2581
2582                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2583                         if (xfer->rx_buf && xfer->tx_buf)
2584                                 return -EINVAL;
2585                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2586                                 return -EINVAL;
2587                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2588                                 return -EINVAL;
2589                 }
2590         }
2591
2592         /**
2593          * Set transfer bits_per_word and max speed as spi device default if
2594          * it is not set for this transfer.
2595          * Set transfer tx_nbits and rx_nbits as single transfer default
2596          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2597          */
2598         message->frame_length = 0;
2599         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2600                 message->frame_length += xfer->len;
2601                 if (!xfer->bits_per_word)
2602                         xfer->bits_per_word = spi->bits_per_word;
2603
2604                 if (!xfer->speed_hz)
2605                         xfer->speed_hz = spi->max_speed_hz;
2606                 if (!xfer->speed_hz)
2607                         xfer->speed_hz = master->max_speed_hz;
2608
2609                 if (master->max_speed_hz &&
2610                     xfer->speed_hz > master->max_speed_hz)
2611                         xfer->speed_hz = master->max_speed_hz;
2612
2613                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2614                         return -EINVAL;
2615
2616                 /*
2617                  * SPI transfer length should be multiple of SPI word size
2618                  * where SPI word size should be power-of-two multiple
2619                  */
2620                 if (xfer->bits_per_word <= 8)
2621                         w_size = 1;
2622                 else if (xfer->bits_per_word <= 16)
2623                         w_size = 2;
2624                 else
2625                         w_size = 4;
2626
2627                 /* No partial transfers accepted */
2628                 if (xfer->len % w_size)
2629                         return -EINVAL;
2630
2631                 if (xfer->speed_hz && master->min_speed_hz &&
2632                     xfer->speed_hz < master->min_speed_hz)
2633                         return -EINVAL;
2634
2635                 if (xfer->tx_buf && !xfer->tx_nbits)
2636                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2637                 if (xfer->rx_buf && !xfer->rx_nbits)
2638                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2639                 /* check transfer tx/rx_nbits:
2640                  * 1. check the value matches one of single, dual and quad
2641                  * 2. check tx/rx_nbits match the mode in spi_device
2642                  */
2643                 if (xfer->tx_buf) {
2644                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2645                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2646                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2647                                 return -EINVAL;
2648                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2649                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2650                                 return -EINVAL;
2651                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2652                                 !(spi->mode & SPI_TX_QUAD))
2653                                 return -EINVAL;
2654                 }
2655                 /* check transfer rx_nbits */
2656                 if (xfer->rx_buf) {
2657                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2658                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2659                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2660                                 return -EINVAL;
2661                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2662                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2663                                 return -EINVAL;
2664                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2665                                 !(spi->mode & SPI_RX_QUAD))
2666                                 return -EINVAL;
2667                 }
2668         }
2669
2670         message->status = -EINPROGRESS;
2671
2672         return 0;
2673 }
2674
2675 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2676 {
2677         struct spi_master *master = spi->master;
2678
2679         message->spi = spi;
2680
2681         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2682         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2683
2684         trace_spi_message_submit(message);
2685
2686         return master->transfer(spi, message);
2687 }
2688
2689 /**
2690  * spi_async - asynchronous SPI transfer
2691  * @spi: device with which data will be exchanged
2692  * @message: describes the data transfers, including completion callback
2693  * Context: any (irqs may be blocked, etc)
2694  *
2695  * This call may be used in_irq and other contexts which can't sleep,
2696  * as well as from task contexts which can sleep.
2697  *
2698  * The completion callback is invoked in a context which can't sleep.
2699  * Before that invocation, the value of message->status is undefined.
2700  * When the callback is issued, message->status holds either zero (to
2701  * indicate complete success) or a negative error code.  After that
2702  * callback returns, the driver which issued the transfer request may
2703  * deallocate the associated memory; it's no longer in use by any SPI
2704  * core or controller driver code.
2705  *
2706  * Note that although all messages to a spi_device are handled in
2707  * FIFO order, messages may go to different devices in other orders.
2708  * Some device might be higher priority, or have various "hard" access
2709  * time requirements, for example.
2710  *
2711  * On detection of any fault during the transfer, processing of
2712  * the entire message is aborted, and the device is deselected.
2713  * Until returning from the associated message completion callback,
2714  * no other spi_message queued to that device will be processed.
2715  * (This rule applies equally to all the synchronous transfer calls,
2716  * which are wrappers around this core asynchronous primitive.)
2717  *
2718  * Return: zero on success, else a negative error code.
2719  */
2720 int spi_async(struct spi_device *spi, struct spi_message *message)
2721 {
2722         struct spi_master *master = spi->master;
2723         int ret;
2724         unsigned long flags;
2725
2726         ret = __spi_validate(spi, message);
2727         if (ret != 0)
2728                 return ret;
2729
2730         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2731
2732         if (master->bus_lock_flag)
2733                 ret = -EBUSY;
2734         else
2735                 ret = __spi_async(spi, message);
2736
2737         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2738
2739         return ret;
2740 }
2741 EXPORT_SYMBOL_GPL(spi_async);
2742
2743 /**
2744  * spi_async_locked - version of spi_async with exclusive bus usage
2745  * @spi: device with which data will be exchanged
2746  * @message: describes the data transfers, including completion callback
2747  * Context: any (irqs may be blocked, etc)
2748  *
2749  * This call may be used in_irq and other contexts which can't sleep,
2750  * as well as from task contexts which can sleep.
2751  *
2752  * The completion callback is invoked in a context which can't sleep.
2753  * Before that invocation, the value of message->status is undefined.
2754  * When the callback is issued, message->status holds either zero (to
2755  * indicate complete success) or a negative error code.  After that
2756  * callback returns, the driver which issued the transfer request may
2757  * deallocate the associated memory; it's no longer in use by any SPI
2758  * core or controller driver code.
2759  *
2760  * Note that although all messages to a spi_device are handled in
2761  * FIFO order, messages may go to different devices in other orders.
2762  * Some device might be higher priority, or have various "hard" access
2763  * time requirements, for example.
2764  *
2765  * On detection of any fault during the transfer, processing of
2766  * the entire message is aborted, and the device is deselected.
2767  * Until returning from the associated message completion callback,
2768  * no other spi_message queued to that device will be processed.
2769  * (This rule applies equally to all the synchronous transfer calls,
2770  * which are wrappers around this core asynchronous primitive.)
2771  *
2772  * Return: zero on success, else a negative error code.
2773  */
2774 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2775 {
2776         struct spi_master *master = spi->master;
2777         int ret;
2778         unsigned long flags;
2779
2780         ret = __spi_validate(spi, message);
2781         if (ret != 0)
2782                 return ret;
2783
2784         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2785
2786         ret = __spi_async(spi, message);
2787
2788         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2789
2790         return ret;
2791
2792 }
2793 EXPORT_SYMBOL_GPL(spi_async_locked);
2794
2795
2796 int spi_flash_read(struct spi_device *spi,
2797                    struct spi_flash_read_message *msg)
2798
2799 {
2800         struct spi_master *master = spi->master;
2801         struct device *rx_dev = NULL;
2802         int ret;
2803
2804         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2805              msg->addr_nbits == SPI_NBITS_DUAL) &&
2806             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2807                 return -EINVAL;
2808         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2809              msg->addr_nbits == SPI_NBITS_QUAD) &&
2810             !(spi->mode & SPI_TX_QUAD))
2811                 return -EINVAL;
2812         if (msg->data_nbits == SPI_NBITS_DUAL &&
2813             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2814                 return -EINVAL;
2815         if (msg->data_nbits == SPI_NBITS_QUAD &&
2816             !(spi->mode &  SPI_RX_QUAD))
2817                 return -EINVAL;
2818
2819         if (master->auto_runtime_pm) {
2820                 ret = pm_runtime_get_sync(master->dev.parent);
2821                 if (ret < 0) {
2822                         dev_err(&master->dev, "Failed to power device: %d\n",
2823                                 ret);
2824                         return ret;
2825                 }
2826         }
2827
2828         mutex_lock(&master->bus_lock_mutex);
2829         mutex_lock(&master->io_mutex);
2830         if (master->dma_rx) {
2831                 rx_dev = master->dma_rx->device->dev;
2832                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2833                                   msg->buf, msg->len,
2834                                   DMA_FROM_DEVICE);
2835                 if (!ret)
2836                         msg->cur_msg_mapped = true;
2837         }
2838         ret = master->spi_flash_read(spi, msg);
2839         if (msg->cur_msg_mapped)
2840                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2841                               DMA_FROM_DEVICE);
2842         mutex_unlock(&master->io_mutex);
2843         mutex_unlock(&master->bus_lock_mutex);
2844
2845         if (master->auto_runtime_pm)
2846                 pm_runtime_put(master->dev.parent);
2847
2848         return ret;
2849 }
2850 EXPORT_SYMBOL_GPL(spi_flash_read);
2851
2852 /*-------------------------------------------------------------------------*/
2853
2854 /* Utility methods for SPI master protocol drivers, layered on
2855  * top of the core.  Some other utility methods are defined as
2856  * inline functions.
2857  */
2858
2859 static void spi_complete(void *arg)
2860 {
2861         complete(arg);
2862 }
2863
2864 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2865 {
2866         DECLARE_COMPLETION_ONSTACK(done);
2867         int status;
2868         struct spi_master *master = spi->master;
2869         unsigned long flags;
2870
2871         status = __spi_validate(spi, message);
2872         if (status != 0)
2873                 return status;
2874
2875         message->complete = spi_complete;
2876         message->context = &done;
2877         message->spi = spi;
2878
2879         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2880         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2881
2882         /* If we're not using the legacy transfer method then we will
2883          * try to transfer in the calling context so special case.
2884          * This code would be less tricky if we could remove the
2885          * support for driver implemented message queues.
2886          */
2887         if (master->transfer == spi_queued_transfer) {
2888                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2889
2890                 trace_spi_message_submit(message);
2891
2892                 status = __spi_queued_transfer(spi, message, false);
2893
2894                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2895         } else {
2896                 status = spi_async_locked(spi, message);
2897         }
2898
2899         if (status == 0) {
2900                 /* Push out the messages in the calling context if we
2901                  * can.
2902                  */
2903                 if (master->transfer == spi_queued_transfer) {
2904                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2905                                                        spi_sync_immediate);
2906                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2907                                                        spi_sync_immediate);
2908                         __spi_pump_messages(master, false);
2909                 }
2910
2911                 wait_for_completion(&done);
2912                 status = message->status;
2913         }
2914         message->context = NULL;
2915         return status;
2916 }
2917
2918 /**
2919  * spi_sync - blocking/synchronous SPI data transfers
2920  * @spi: device with which data will be exchanged
2921  * @message: describes the data transfers
2922  * Context: can sleep
2923  *
2924  * This call may only be used from a context that may sleep.  The sleep
2925  * is non-interruptible, and has no timeout.  Low-overhead controller
2926  * drivers may DMA directly into and out of the message buffers.
2927  *
2928  * Note that the SPI device's chip select is active during the message,
2929  * and then is normally disabled between messages.  Drivers for some
2930  * frequently-used devices may want to minimize costs of selecting a chip,
2931  * by leaving it selected in anticipation that the next message will go
2932  * to the same chip.  (That may increase power usage.)
2933  *
2934  * Also, the caller is guaranteeing that the memory associated with the
2935  * message will not be freed before this call returns.
2936  *
2937  * Return: zero on success, else a negative error code.
2938  */
2939 int spi_sync(struct spi_device *spi, struct spi_message *message)
2940 {
2941         int ret;
2942
2943         mutex_lock(&spi->master->bus_lock_mutex);
2944         ret = __spi_sync(spi, message);
2945         mutex_unlock(&spi->master->bus_lock_mutex);
2946
2947         return ret;
2948 }
2949 EXPORT_SYMBOL_GPL(spi_sync);
2950
2951 /**
2952  * spi_sync_locked - version of spi_sync with exclusive bus usage
2953  * @spi: device with which data will be exchanged
2954  * @message: describes the data transfers
2955  * Context: can sleep
2956  *
2957  * This call may only be used from a context that may sleep.  The sleep
2958  * is non-interruptible, and has no timeout.  Low-overhead controller
2959  * drivers may DMA directly into and out of the message buffers.
2960  *
2961  * This call should be used by drivers that require exclusive access to the
2962  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2963  * be released by a spi_bus_unlock call when the exclusive access is over.
2964  *
2965  * Return: zero on success, else a negative error code.
2966  */
2967 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2968 {
2969         return __spi_sync(spi, message);
2970 }
2971 EXPORT_SYMBOL_GPL(spi_sync_locked);
2972
2973 /**
2974  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2975  * @master: SPI bus master that should be locked for exclusive bus access
2976  * Context: can sleep
2977  *
2978  * This call may only be used from a context that may sleep.  The sleep
2979  * is non-interruptible, and has no timeout.
2980  *
2981  * This call should be used by drivers that require exclusive access to the
2982  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2983  * exclusive access is over. Data transfer must be done by spi_sync_locked
2984  * and spi_async_locked calls when the SPI bus lock is held.
2985  *
2986  * Return: always zero.
2987  */
2988 int spi_bus_lock(struct spi_master *master)
2989 {
2990         unsigned long flags;
2991
2992         mutex_lock(&master->bus_lock_mutex);
2993
2994         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2995         master->bus_lock_flag = 1;
2996         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2997
2998         /* mutex remains locked until spi_bus_unlock is called */
2999
3000         return 0;
3001 }
3002 EXPORT_SYMBOL_GPL(spi_bus_lock);
3003
3004 /**
3005  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3006  * @master: SPI bus master that was locked for exclusive bus access
3007  * Context: can sleep
3008  *
3009  * This call may only be used from a context that may sleep.  The sleep
3010  * is non-interruptible, and has no timeout.
3011  *
3012  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3013  * call.
3014  *
3015  * Return: always zero.
3016  */
3017 int spi_bus_unlock(struct spi_master *master)
3018 {
3019         master->bus_lock_flag = 0;
3020
3021         mutex_unlock(&master->bus_lock_mutex);
3022
3023         return 0;
3024 }
3025 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3026
3027 /* portable code must never pass more than 32 bytes */
3028 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3029
3030 static u8       *buf;
3031
3032 /**
3033  * spi_write_then_read - SPI synchronous write followed by read
3034  * @spi: device with which data will be exchanged
3035  * @txbuf: data to be written (need not be dma-safe)
3036  * @n_tx: size of txbuf, in bytes
3037  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3038  * @n_rx: size of rxbuf, in bytes
3039  * Context: can sleep
3040  *
3041  * This performs a half duplex MicroWire style transaction with the
3042  * device, sending txbuf and then reading rxbuf.  The return value
3043  * is zero for success, else a negative errno status code.
3044  * This call may only be used from a context that may sleep.
3045  *
3046  * Parameters to this routine are always copied using a small buffer;
3047  * portable code should never use this for more than 32 bytes.
3048  * Performance-sensitive or bulk transfer code should instead use
3049  * spi_{async,sync}() calls with dma-safe buffers.
3050  *
3051  * Return: zero on success, else a negative error code.
3052  */
3053 int spi_write_then_read(struct spi_device *spi,
3054                 const void *txbuf, unsigned n_tx,
3055                 void *rxbuf, unsigned n_rx)
3056 {
3057         static DEFINE_MUTEX(lock);
3058
3059         int                     status;
3060         struct spi_message      message;
3061         struct spi_transfer     x[2];
3062         u8                      *local_buf;
3063
3064         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3065          * copying here, (as a pure convenience thing), but we can
3066          * keep heap costs out of the hot path unless someone else is
3067          * using the pre-allocated buffer or the transfer is too large.
3068          */
3069         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3070                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3071                                     GFP_KERNEL | GFP_DMA);
3072                 if (!local_buf)
3073                         return -ENOMEM;
3074         } else {
3075                 local_buf = buf;
3076         }
3077
3078         spi_message_init(&message);
3079         memset(x, 0, sizeof(x));
3080         if (n_tx) {
3081                 x[0].len = n_tx;
3082                 spi_message_add_tail(&x[0], &message);
3083         }
3084         if (n_rx) {
3085                 x[1].len = n_rx;
3086                 spi_message_add_tail(&x[1], &message);
3087         }
3088
3089         memcpy(local_buf, txbuf, n_tx);
3090         x[0].tx_buf = local_buf;
3091         x[1].rx_buf = local_buf + n_tx;
3092
3093         /* do the i/o */
3094         status = spi_sync(spi, &message);
3095         if (status == 0)
3096                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3097
3098         if (x[0].tx_buf == buf)
3099                 mutex_unlock(&lock);
3100         else
3101                 kfree(local_buf);
3102
3103         return status;
3104 }
3105 EXPORT_SYMBOL_GPL(spi_write_then_read);
3106
3107 /*-------------------------------------------------------------------------*/
3108
3109 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3110 static int __spi_of_device_match(struct device *dev, void *data)
3111 {
3112         return dev->of_node == data;
3113 }
3114
3115 /* must call put_device() when done with returned spi_device device */
3116 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3117 {
3118         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3119                                                 __spi_of_device_match);
3120         return dev ? to_spi_device(dev) : NULL;
3121 }
3122
3123 static int __spi_of_master_match(struct device *dev, const void *data)
3124 {
3125         return dev->of_node == data;
3126 }
3127
3128 /* the spi masters are not using spi_bus, so we find it with another way */
3129 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3130 {
3131         struct device *dev;
3132
3133         dev = class_find_device(&spi_master_class, NULL, node,
3134                                 __spi_of_master_match);
3135         if (!dev)
3136                 return NULL;
3137
3138         /* reference got in class_find_device */
3139         return container_of(dev, struct spi_master, dev);
3140 }
3141
3142 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3143                          void *arg)
3144 {
3145         struct of_reconfig_data *rd = arg;
3146         struct spi_master *master;
3147         struct spi_device *spi;
3148
3149         switch (of_reconfig_get_state_change(action, arg)) {
3150         case OF_RECONFIG_CHANGE_ADD:
3151                 master = of_find_spi_master_by_node(rd->dn->parent);
3152                 if (master == NULL)
3153                         return NOTIFY_OK;       /* not for us */
3154
3155                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3156                         put_device(&master->dev);
3157                         return NOTIFY_OK;
3158                 }
3159
3160                 spi = of_register_spi_device(master, rd->dn);
3161                 put_device(&master->dev);
3162
3163                 if (IS_ERR(spi)) {
3164                         pr_err("%s: failed to create for '%s'\n",
3165                                         __func__, rd->dn->full_name);
3166                         of_node_clear_flag(rd->dn, OF_POPULATED);
3167                         return notifier_from_errno(PTR_ERR(spi));
3168                 }
3169                 break;
3170
3171         case OF_RECONFIG_CHANGE_REMOVE:
3172                 /* already depopulated? */
3173                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3174                         return NOTIFY_OK;
3175
3176                 /* find our device by node */
3177                 spi = of_find_spi_device_by_node(rd->dn);
3178                 if (spi == NULL)
3179                         return NOTIFY_OK;       /* no? not meant for us */
3180
3181                 /* unregister takes one ref away */
3182                 spi_unregister_device(spi);
3183
3184                 /* and put the reference of the find */
3185                 put_device(&spi->dev);
3186                 break;
3187         }
3188
3189         return NOTIFY_OK;
3190 }
3191
3192 static struct notifier_block spi_of_notifier = {
3193         .notifier_call = of_spi_notify,
3194 };
3195 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3196 extern struct notifier_block spi_of_notifier;
3197 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3198
3199 #if IS_ENABLED(CONFIG_ACPI)
3200 static int spi_acpi_master_match(struct device *dev, const void *data)
3201 {
3202         return ACPI_COMPANION(dev->parent) == data;
3203 }
3204
3205 static int spi_acpi_device_match(struct device *dev, void *data)
3206 {
3207         return ACPI_COMPANION(dev) == data;
3208 }
3209
3210 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3211 {
3212         struct device *dev;
3213
3214         dev = class_find_device(&spi_master_class, NULL, adev,
3215                                 spi_acpi_master_match);
3216         if (!dev)
3217                 return NULL;
3218
3219         return container_of(dev, struct spi_master, dev);
3220 }
3221
3222 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3223 {
3224         struct device *dev;
3225
3226         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3227
3228         return dev ? to_spi_device(dev) : NULL;
3229 }
3230
3231 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3232                            void *arg)
3233 {
3234         struct acpi_device *adev = arg;
3235         struct spi_master *master;
3236         struct spi_device *spi;
3237
3238         switch (value) {
3239         case ACPI_RECONFIG_DEVICE_ADD:
3240                 master = acpi_spi_find_master_by_adev(adev->parent);
3241                 if (!master)
3242                         break;
3243
3244                 acpi_register_spi_device(master, adev);
3245                 put_device(&master->dev);
3246                 break;
3247         case ACPI_RECONFIG_DEVICE_REMOVE:
3248                 if (!acpi_device_enumerated(adev))
3249                         break;
3250
3251                 spi = acpi_spi_find_device_by_adev(adev);
3252                 if (!spi)
3253                         break;
3254
3255                 spi_unregister_device(spi);
3256                 put_device(&spi->dev);
3257                 break;
3258         }
3259
3260         return NOTIFY_OK;
3261 }
3262
3263 static struct notifier_block spi_acpi_notifier = {
3264         .notifier_call = acpi_spi_notify,
3265 };
3266 #else
3267 extern struct notifier_block spi_acpi_notifier;
3268 #endif
3269
3270 static int __init spi_init(void)
3271 {
3272         int     status;
3273
3274         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3275         if (!buf) {
3276                 status = -ENOMEM;
3277                 goto err0;
3278         }
3279
3280         status = bus_register(&spi_bus_type);
3281         if (status < 0)
3282                 goto err1;
3283
3284         status = class_register(&spi_master_class);
3285         if (status < 0)
3286                 goto err2;
3287
3288         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3289                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3290         if (IS_ENABLED(CONFIG_ACPI))
3291                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3292
3293         return 0;
3294
3295 err2:
3296         bus_unregister(&spi_bus_type);
3297 err1:
3298         kfree(buf);
3299         buf = NULL;
3300 err0:
3301         return status;
3302 }
3303
3304 /* board_info is normally registered in arch_initcall(),
3305  * but even essential drivers wait till later
3306  *
3307  * REVISIT only boardinfo really needs static linking. the rest (device and
3308  * driver registration) _could_ be dynamically linked (modular) ... costs
3309  * include needing to have boardinfo data structures be much more public.
3310  */
3311 postcore_initcall(spi_init);
3312