b4a8bb7759b2cdc7cf2a4e9688cda03523f431a9
[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 <uapi/linux/sched/types.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
39 #include <linux/ioport.h>
40 #include <linux/acpi.h>
41 #include <linux/highmem.h>
42
43 #define CREATE_TRACE_POINTS
44 #include <trace/events/spi.h>
45
46 static void spidev_release(struct device *dev)
47 {
48         struct spi_device       *spi = to_spi_device(dev);
49
50         /* spi masters may cleanup for released devices */
51         if (spi->master->cleanup)
52                 spi->master->cleanup(spi);
53
54         spi_master_put(spi->master);
55         kfree(spi);
56 }
57
58 static ssize_t
59 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
60 {
61         const struct spi_device *spi = to_spi_device(dev);
62         int len;
63
64         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
65         if (len != -ENODEV)
66                 return len;
67
68         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
69 }
70 static DEVICE_ATTR_RO(modalias);
71
72 #define SPI_STATISTICS_ATTRS(field, file)                               \
73 static ssize_t spi_master_##field##_show(struct device *dev,            \
74                                          struct device_attribute *attr, \
75                                          char *buf)                     \
76 {                                                                       \
77         struct spi_master *master = container_of(dev,                   \
78                                                  struct spi_master, dev); \
79         return spi_statistics_##field##_show(&master->statistics, buf); \
80 }                                                                       \
81 static struct device_attribute dev_attr_spi_master_##field = {          \
82         .attr = { .name = file, .mode = S_IRUGO },                      \
83         .show = spi_master_##field##_show,                              \
84 };                                                                      \
85 static ssize_t spi_device_##field##_show(struct device *dev,            \
86                                          struct device_attribute *attr, \
87                                         char *buf)                      \
88 {                                                                       \
89         struct spi_device *spi = to_spi_device(dev);                    \
90         return spi_statistics_##field##_show(&spi->statistics, buf);    \
91 }                                                                       \
92 static struct device_attribute dev_attr_spi_device_##field = {          \
93         .attr = { .name = file, .mode = S_IRUGO },                      \
94         .show = spi_device_##field##_show,                              \
95 }
96
97 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
98 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
99                                             char *buf)                  \
100 {                                                                       \
101         unsigned long flags;                                            \
102         ssize_t len;                                                    \
103         spin_lock_irqsave(&stat->lock, flags);                          \
104         len = sprintf(buf, format_string, stat->field);                 \
105         spin_unlock_irqrestore(&stat->lock, flags);                     \
106         return len;                                                     \
107 }                                                                       \
108 SPI_STATISTICS_ATTRS(name, file)
109
110 #define SPI_STATISTICS_SHOW(field, format_string)                       \
111         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
112                                  field, format_string)
113
114 SPI_STATISTICS_SHOW(messages, "%lu");
115 SPI_STATISTICS_SHOW(transfers, "%lu");
116 SPI_STATISTICS_SHOW(errors, "%lu");
117 SPI_STATISTICS_SHOW(timedout, "%lu");
118
119 SPI_STATISTICS_SHOW(spi_sync, "%lu");
120 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
121 SPI_STATISTICS_SHOW(spi_async, "%lu");
122
123 SPI_STATISTICS_SHOW(bytes, "%llu");
124 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
125 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
126
127 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
128         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
129                                  "transfer_bytes_histo_" number,        \
130                                  transfer_bytes_histo[index],  "%lu")
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
147 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
148
149 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
150
151 static struct attribute *spi_dev_attrs[] = {
152         &dev_attr_modalias.attr,
153         NULL,
154 };
155
156 static const struct attribute_group spi_dev_group = {
157         .attrs  = spi_dev_attrs,
158 };
159
160 static struct attribute *spi_device_statistics_attrs[] = {
161         &dev_attr_spi_device_messages.attr,
162         &dev_attr_spi_device_transfers.attr,
163         &dev_attr_spi_device_errors.attr,
164         &dev_attr_spi_device_timedout.attr,
165         &dev_attr_spi_device_spi_sync.attr,
166         &dev_attr_spi_device_spi_sync_immediate.attr,
167         &dev_attr_spi_device_spi_async.attr,
168         &dev_attr_spi_device_bytes.attr,
169         &dev_attr_spi_device_bytes_rx.attr,
170         &dev_attr_spi_device_bytes_tx.attr,
171         &dev_attr_spi_device_transfer_bytes_histo0.attr,
172         &dev_attr_spi_device_transfer_bytes_histo1.attr,
173         &dev_attr_spi_device_transfer_bytes_histo2.attr,
174         &dev_attr_spi_device_transfer_bytes_histo3.attr,
175         &dev_attr_spi_device_transfer_bytes_histo4.attr,
176         &dev_attr_spi_device_transfer_bytes_histo5.attr,
177         &dev_attr_spi_device_transfer_bytes_histo6.attr,
178         &dev_attr_spi_device_transfer_bytes_histo7.attr,
179         &dev_attr_spi_device_transfer_bytes_histo8.attr,
180         &dev_attr_spi_device_transfer_bytes_histo9.attr,
181         &dev_attr_spi_device_transfer_bytes_histo10.attr,
182         &dev_attr_spi_device_transfer_bytes_histo11.attr,
183         &dev_attr_spi_device_transfer_bytes_histo12.attr,
184         &dev_attr_spi_device_transfer_bytes_histo13.attr,
185         &dev_attr_spi_device_transfer_bytes_histo14.attr,
186         &dev_attr_spi_device_transfer_bytes_histo15.attr,
187         &dev_attr_spi_device_transfer_bytes_histo16.attr,
188         &dev_attr_spi_device_transfers_split_maxsize.attr,
189         NULL,
190 };
191
192 static const struct attribute_group spi_device_statistics_group = {
193         .name  = "statistics",
194         .attrs  = spi_device_statistics_attrs,
195 };
196
197 static const struct attribute_group *spi_dev_groups[] = {
198         &spi_dev_group,
199         &spi_device_statistics_group,
200         NULL,
201 };
202
203 static struct attribute *spi_master_statistics_attrs[] = {
204         &dev_attr_spi_master_messages.attr,
205         &dev_attr_spi_master_transfers.attr,
206         &dev_attr_spi_master_errors.attr,
207         &dev_attr_spi_master_timedout.attr,
208         &dev_attr_spi_master_spi_sync.attr,
209         &dev_attr_spi_master_spi_sync_immediate.attr,
210         &dev_attr_spi_master_spi_async.attr,
211         &dev_attr_spi_master_bytes.attr,
212         &dev_attr_spi_master_bytes_rx.attr,
213         &dev_attr_spi_master_bytes_tx.attr,
214         &dev_attr_spi_master_transfer_bytes_histo0.attr,
215         &dev_attr_spi_master_transfer_bytes_histo1.attr,
216         &dev_attr_spi_master_transfer_bytes_histo2.attr,
217         &dev_attr_spi_master_transfer_bytes_histo3.attr,
218         &dev_attr_spi_master_transfer_bytes_histo4.attr,
219         &dev_attr_spi_master_transfer_bytes_histo5.attr,
220         &dev_attr_spi_master_transfer_bytes_histo6.attr,
221         &dev_attr_spi_master_transfer_bytes_histo7.attr,
222         &dev_attr_spi_master_transfer_bytes_histo8.attr,
223         &dev_attr_spi_master_transfer_bytes_histo9.attr,
224         &dev_attr_spi_master_transfer_bytes_histo10.attr,
225         &dev_attr_spi_master_transfer_bytes_histo11.attr,
226         &dev_attr_spi_master_transfer_bytes_histo12.attr,
227         &dev_attr_spi_master_transfer_bytes_histo13.attr,
228         &dev_attr_spi_master_transfer_bytes_histo14.attr,
229         &dev_attr_spi_master_transfer_bytes_histo15.attr,
230         &dev_attr_spi_master_transfer_bytes_histo16.attr,
231         &dev_attr_spi_master_transfers_split_maxsize.attr,
232         NULL,
233 };
234
235 static const struct attribute_group spi_master_statistics_group = {
236         .name  = "statistics",
237         .attrs  = spi_master_statistics_attrs,
238 };
239
240 static const struct attribute_group *spi_master_groups[] = {
241         &spi_master_statistics_group,
242         NULL,
243 };
244
245 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
246                                        struct spi_transfer *xfer,
247                                        struct spi_master *master)
248 {
249         unsigned long flags;
250         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
251
252         if (l2len < 0)
253                 l2len = 0;
254
255         spin_lock_irqsave(&stats->lock, flags);
256
257         stats->transfers++;
258         stats->transfer_bytes_histo[l2len]++;
259
260         stats->bytes += xfer->len;
261         if ((xfer->tx_buf) &&
262             (xfer->tx_buf != master->dummy_tx))
263                 stats->bytes_tx += xfer->len;
264         if ((xfer->rx_buf) &&
265             (xfer->rx_buf != master->dummy_rx))
266                 stats->bytes_rx += xfer->len;
267
268         spin_unlock_irqrestore(&stats->lock, flags);
269 }
270 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
271
272 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
273  * and the sysfs version makes coldplug work too.
274  */
275
276 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
277                                                 const struct spi_device *sdev)
278 {
279         while (id->name[0]) {
280                 if (!strcmp(sdev->modalias, id->name))
281                         return id;
282                 id++;
283         }
284         return NULL;
285 }
286
287 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
288 {
289         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
290
291         return spi_match_id(sdrv->id_table, sdev);
292 }
293 EXPORT_SYMBOL_GPL(spi_get_device_id);
294
295 static int spi_match_device(struct device *dev, struct device_driver *drv)
296 {
297         const struct spi_device *spi = to_spi_device(dev);
298         const struct spi_driver *sdrv = to_spi_driver(drv);
299
300         /* Attempt an OF style match */
301         if (of_driver_match_device(dev, drv))
302                 return 1;
303
304         /* Then try ACPI */
305         if (acpi_driver_match_device(dev, drv))
306                 return 1;
307
308         if (sdrv->id_table)
309                 return !!spi_match_id(sdrv->id_table, spi);
310
311         return strcmp(spi->modalias, drv->name) == 0;
312 }
313
314 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
315 {
316         const struct spi_device         *spi = to_spi_device(dev);
317         int rc;
318
319         rc = acpi_device_uevent_modalias(dev, env);
320         if (rc != -ENODEV)
321                 return rc;
322
323         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
324         return 0;
325 }
326
327 struct bus_type spi_bus_type = {
328         .name           = "spi",
329         .dev_groups     = spi_dev_groups,
330         .match          = spi_match_device,
331         .uevent         = spi_uevent,
332 };
333 EXPORT_SYMBOL_GPL(spi_bus_type);
334
335
336 static int spi_drv_probe(struct device *dev)
337 {
338         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
339         struct spi_device               *spi = to_spi_device(dev);
340         int ret;
341
342         ret = of_clk_set_defaults(dev->of_node, false);
343         if (ret)
344                 return ret;
345
346         if (dev->of_node) {
347                 spi->irq = of_irq_get(dev->of_node, 0);
348                 if (spi->irq == -EPROBE_DEFER)
349                         return -EPROBE_DEFER;
350                 if (spi->irq < 0)
351                         spi->irq = 0;
352         }
353
354         ret = dev_pm_domain_attach(dev, true);
355         if (ret != -EPROBE_DEFER) {
356                 ret = sdrv->probe(spi);
357                 if (ret)
358                         dev_pm_domain_detach(dev, true);
359         }
360
361         return ret;
362 }
363
364 static int spi_drv_remove(struct device *dev)
365 {
366         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
367         int ret;
368
369         ret = sdrv->remove(to_spi_device(dev));
370         dev_pm_domain_detach(dev, true);
371
372         return ret;
373 }
374
375 static void spi_drv_shutdown(struct device *dev)
376 {
377         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
378
379         sdrv->shutdown(to_spi_device(dev));
380 }
381
382 /**
383  * __spi_register_driver - register a SPI driver
384  * @owner: owner module of the driver to register
385  * @sdrv: the driver to register
386  * Context: can sleep
387  *
388  * Return: zero on success, else a negative error code.
389  */
390 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
391 {
392         sdrv->driver.owner = owner;
393         sdrv->driver.bus = &spi_bus_type;
394         if (sdrv->probe)
395                 sdrv->driver.probe = spi_drv_probe;
396         if (sdrv->remove)
397                 sdrv->driver.remove = spi_drv_remove;
398         if (sdrv->shutdown)
399                 sdrv->driver.shutdown = spi_drv_shutdown;
400         return driver_register(&sdrv->driver);
401 }
402 EXPORT_SYMBOL_GPL(__spi_register_driver);
403
404 /*-------------------------------------------------------------------------*/
405
406 /* SPI devices should normally not be created by SPI device drivers; that
407  * would make them board-specific.  Similarly with SPI master drivers.
408  * Device registration normally goes into like arch/.../mach.../board-YYY.c
409  * with other readonly (flashable) information about mainboard devices.
410  */
411
412 struct boardinfo {
413         struct list_head        list;
414         struct spi_board_info   board_info;
415 };
416
417 static LIST_HEAD(board_list);
418 static LIST_HEAD(spi_master_list);
419
420 /*
421  * Used to protect add/del opertion for board_info list and
422  * spi_master list, and their matching process
423  */
424 static DEFINE_MUTEX(board_lock);
425
426 /**
427  * spi_alloc_device - Allocate a new SPI device
428  * @master: Controller to which device is connected
429  * Context: can sleep
430  *
431  * Allows a driver to allocate and initialize a spi_device without
432  * registering it immediately.  This allows a driver to directly
433  * fill the spi_device with device parameters before calling
434  * spi_add_device() on it.
435  *
436  * Caller is responsible to call spi_add_device() on the returned
437  * spi_device structure to add it to the SPI master.  If the caller
438  * needs to discard the spi_device without adding it, then it should
439  * call spi_dev_put() on it.
440  *
441  * Return: a pointer to the new device, or NULL.
442  */
443 struct spi_device *spi_alloc_device(struct spi_master *master)
444 {
445         struct spi_device       *spi;
446
447         if (!spi_master_get(master))
448                 return NULL;
449
450         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
451         if (!spi) {
452                 spi_master_put(master);
453                 return NULL;
454         }
455
456         spi->master = master;
457         spi->dev.parent = &master->dev;
458         spi->dev.bus = &spi_bus_type;
459         spi->dev.release = spidev_release;
460         spi->cs_gpio = -ENOENT;
461
462         spin_lock_init(&spi->statistics.lock);
463
464         device_initialize(&spi->dev);
465         return spi;
466 }
467 EXPORT_SYMBOL_GPL(spi_alloc_device);
468
469 static void spi_dev_set_name(struct spi_device *spi)
470 {
471         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
472
473         if (adev) {
474                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
475                 return;
476         }
477
478         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
479                      spi->chip_select);
480 }
481
482 static int spi_dev_check(struct device *dev, void *data)
483 {
484         struct spi_device *spi = to_spi_device(dev);
485         struct spi_device *new_spi = data;
486
487         if (spi->master == new_spi->master &&
488             spi->chip_select == new_spi->chip_select)
489                 return -EBUSY;
490         return 0;
491 }
492
493 /**
494  * spi_add_device - Add spi_device allocated with spi_alloc_device
495  * @spi: spi_device to register
496  *
497  * Companion function to spi_alloc_device.  Devices allocated with
498  * spi_alloc_device can be added onto the spi bus with this function.
499  *
500  * Return: 0 on success; negative errno on failure
501  */
502 int spi_add_device(struct spi_device *spi)
503 {
504         static DEFINE_MUTEX(spi_add_lock);
505         struct spi_master *master = spi->master;
506         struct device *dev = master->dev.parent;
507         int status;
508
509         /* Chipselects are numbered 0..max; validate. */
510         if (spi->chip_select >= master->num_chipselect) {
511                 dev_err(dev, "cs%d >= max %d\n",
512                         spi->chip_select,
513                         master->num_chipselect);
514                 return -EINVAL;
515         }
516
517         /* Set the bus ID string */
518         spi_dev_set_name(spi);
519
520         /* We need to make sure there's no other device with this
521          * chipselect **BEFORE** we call setup(), else we'll trash
522          * its configuration.  Lock against concurrent add() calls.
523          */
524         mutex_lock(&spi_add_lock);
525
526         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
527         if (status) {
528                 dev_err(dev, "chipselect %d already in use\n",
529                                 spi->chip_select);
530                 goto done;
531         }
532
533         if (master->cs_gpios)
534                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
535
536         /* Drivers may modify this initial i/o setup, but will
537          * normally rely on the device being setup.  Devices
538          * using SPI_CS_HIGH can't coexist well otherwise...
539          */
540         status = spi_setup(spi);
541         if (status < 0) {
542                 dev_err(dev, "can't setup %s, status %d\n",
543                                 dev_name(&spi->dev), status);
544                 goto done;
545         }
546
547         /* Device may be bound to an active driver when this returns */
548         status = device_add(&spi->dev);
549         if (status < 0)
550                 dev_err(dev, "can't add %s, status %d\n",
551                                 dev_name(&spi->dev), status);
552         else
553                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
554
555 done:
556         mutex_unlock(&spi_add_lock);
557         return status;
558 }
559 EXPORT_SYMBOL_GPL(spi_add_device);
560
561 /**
562  * spi_new_device - instantiate one new SPI device
563  * @master: Controller to which device is connected
564  * @chip: Describes the SPI device
565  * Context: can sleep
566  *
567  * On typical mainboards, this is purely internal; and it's not needed
568  * after board init creates the hard-wired devices.  Some development
569  * platforms may not be able to use spi_register_board_info though, and
570  * this is exported so that for example a USB or parport based adapter
571  * driver could add devices (which it would learn about out-of-band).
572  *
573  * Return: the new device, or NULL.
574  */
575 struct spi_device *spi_new_device(struct spi_master *master,
576                                   struct spi_board_info *chip)
577 {
578         struct spi_device       *proxy;
579         int                     status;
580
581         /* NOTE:  caller did any chip->bus_num checks necessary.
582          *
583          * Also, unless we change the return value convention to use
584          * error-or-pointer (not NULL-or-pointer), troubleshootability
585          * suggests syslogged diagnostics are best here (ugh).
586          */
587
588         proxy = spi_alloc_device(master);
589         if (!proxy)
590                 return NULL;
591
592         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
593
594         proxy->chip_select = chip->chip_select;
595         proxy->max_speed_hz = chip->max_speed_hz;
596         proxy->mode = chip->mode;
597         proxy->irq = chip->irq;
598         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
599         proxy->dev.platform_data = (void *) chip->platform_data;
600         proxy->controller_data = chip->controller_data;
601         proxy->controller_state = NULL;
602
603         status = spi_add_device(proxy);
604         if (status < 0) {
605                 spi_dev_put(proxy);
606                 return NULL;
607         }
608
609         return proxy;
610 }
611 EXPORT_SYMBOL_GPL(spi_new_device);
612
613 /**
614  * spi_unregister_device - unregister a single SPI device
615  * @spi: spi_device to unregister
616  *
617  * Start making the passed SPI device vanish. Normally this would be handled
618  * by spi_unregister_master().
619  */
620 void spi_unregister_device(struct spi_device *spi)
621 {
622         if (!spi)
623                 return;
624
625         if (spi->dev.of_node) {
626                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
627                 of_node_put(spi->dev.of_node);
628         }
629         if (ACPI_COMPANION(&spi->dev))
630                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
631         device_unregister(&spi->dev);
632 }
633 EXPORT_SYMBOL_GPL(spi_unregister_device);
634
635 static void spi_match_master_to_boardinfo(struct spi_master *master,
636                                 struct spi_board_info *bi)
637 {
638         struct spi_device *dev;
639
640         if (master->bus_num != bi->bus_num)
641                 return;
642
643         dev = spi_new_device(master, bi);
644         if (!dev)
645                 dev_err(master->dev.parent, "can't create new device for %s\n",
646                         bi->modalias);
647 }
648
649 /**
650  * spi_register_board_info - register SPI devices for a given board
651  * @info: array of chip descriptors
652  * @n: how many descriptors are provided
653  * Context: can sleep
654  *
655  * Board-specific early init code calls this (probably during arch_initcall)
656  * with segments of the SPI device table.  Any device nodes are created later,
657  * after the relevant parent SPI controller (bus_num) is defined.  We keep
658  * this table of devices forever, so that reloading a controller driver will
659  * not make Linux forget about these hard-wired devices.
660  *
661  * Other code can also call this, e.g. a particular add-on board might provide
662  * SPI devices through its expansion connector, so code initializing that board
663  * would naturally declare its SPI devices.
664  *
665  * The board info passed can safely be __initdata ... but be careful of
666  * any embedded pointers (platform_data, etc), they're copied as-is.
667  *
668  * Return: zero on success, else a negative error code.
669  */
670 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
671 {
672         struct boardinfo *bi;
673         int i;
674
675         if (!n)
676                 return -EINVAL;
677
678         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
679         if (!bi)
680                 return -ENOMEM;
681
682         for (i = 0; i < n; i++, bi++, info++) {
683                 struct spi_master *master;
684
685                 memcpy(&bi->board_info, info, sizeof(*info));
686                 mutex_lock(&board_lock);
687                 list_add_tail(&bi->list, &board_list);
688                 list_for_each_entry(master, &spi_master_list, list)
689                         spi_match_master_to_boardinfo(master, &bi->board_info);
690                 mutex_unlock(&board_lock);
691         }
692
693         return 0;
694 }
695
696 /*-------------------------------------------------------------------------*/
697
698 static void spi_set_cs(struct spi_device *spi, bool enable)
699 {
700         if (spi->mode & SPI_CS_HIGH)
701                 enable = !enable;
702
703         if (gpio_is_valid(spi->cs_gpio)) {
704                 gpio_set_value(spi->cs_gpio, !enable);
705                 /* Some SPI masters need both GPIO CS & slave_select */
706                 if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
707                     spi->master->set_cs)
708                         spi->master->set_cs(spi, !enable);
709         } else if (spi->master->set_cs) {
710                 spi->master->set_cs(spi, !enable);
711         }
712 }
713
714 #ifdef CONFIG_HAS_DMA
715 static int spi_map_buf(struct spi_master *master, struct device *dev,
716                        struct sg_table *sgt, void *buf, size_t len,
717                        enum dma_data_direction dir)
718 {
719         const bool vmalloced_buf = is_vmalloc_addr(buf);
720         unsigned int max_seg_size = dma_get_max_seg_size(dev);
721 #ifdef CONFIG_HIGHMEM
722         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
723                                 (unsigned long)buf < (PKMAP_BASE +
724                                         (LAST_PKMAP * PAGE_SIZE)));
725 #else
726         const bool kmap_buf = false;
727 #endif
728         int desc_len;
729         int sgs;
730         struct page *vm_page;
731         struct scatterlist *sg;
732         void *sg_buf;
733         size_t min;
734         int i, ret;
735
736         if (vmalloced_buf || kmap_buf) {
737                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
738                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
739         } else if (virt_addr_valid(buf)) {
740                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
741                 sgs = DIV_ROUND_UP(len, desc_len);
742         } else {
743                 return -EINVAL;
744         }
745
746         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
747         if (ret != 0)
748                 return ret;
749
750         sg = &sgt->sgl[0];
751         for (i = 0; i < sgs; i++) {
752
753                 if (vmalloced_buf || kmap_buf) {
754                         min = min_t(size_t,
755                                     len, desc_len - offset_in_page(buf));
756                         if (vmalloced_buf)
757                                 vm_page = vmalloc_to_page(buf);
758                         else
759                                 vm_page = kmap_to_page(buf);
760                         if (!vm_page) {
761                                 sg_free_table(sgt);
762                                 return -ENOMEM;
763                         }
764                         sg_set_page(sg, vm_page,
765                                     min, offset_in_page(buf));
766                 } else {
767                         min = min_t(size_t, len, desc_len);
768                         sg_buf = buf;
769                         sg_set_buf(sg, sg_buf, min);
770                 }
771
772                 buf += min;
773                 len -= min;
774                 sg = sg_next(sg);
775         }
776
777         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
778         if (!ret)
779                 ret = -ENOMEM;
780         if (ret < 0) {
781                 sg_free_table(sgt);
782                 return ret;
783         }
784
785         sgt->nents = ret;
786
787         return 0;
788 }
789
790 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
791                           struct sg_table *sgt, enum dma_data_direction dir)
792 {
793         if (sgt->orig_nents) {
794                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
795                 sg_free_table(sgt);
796         }
797 }
798
799 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
800 {
801         struct device *tx_dev, *rx_dev;
802         struct spi_transfer *xfer;
803         int ret;
804
805         if (!master->can_dma)
806                 return 0;
807
808         if (master->dma_tx)
809                 tx_dev = master->dma_tx->device->dev;
810         else
811                 tx_dev = master->dev.parent;
812
813         if (master->dma_rx)
814                 rx_dev = master->dma_rx->device->dev;
815         else
816                 rx_dev = master->dev.parent;
817
818         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
819                 if (!master->can_dma(master, msg->spi, xfer))
820                         continue;
821
822                 if (xfer->tx_buf != NULL) {
823                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
824                                           (void *)xfer->tx_buf, xfer->len,
825                                           DMA_TO_DEVICE);
826                         if (ret != 0)
827                                 return ret;
828                 }
829
830                 if (xfer->rx_buf != NULL) {
831                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
832                                           xfer->rx_buf, xfer->len,
833                                           DMA_FROM_DEVICE);
834                         if (ret != 0) {
835                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
836                                               DMA_TO_DEVICE);
837                                 return ret;
838                         }
839                 }
840         }
841
842         master->cur_msg_mapped = true;
843
844         return 0;
845 }
846
847 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
848 {
849         struct spi_transfer *xfer;
850         struct device *tx_dev, *rx_dev;
851
852         if (!master->cur_msg_mapped || !master->can_dma)
853                 return 0;
854
855         if (master->dma_tx)
856                 tx_dev = master->dma_tx->device->dev;
857         else
858                 tx_dev = master->dev.parent;
859
860         if (master->dma_rx)
861                 rx_dev = master->dma_rx->device->dev;
862         else
863                 rx_dev = master->dev.parent;
864
865         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
866                 if (!master->can_dma(master, msg->spi, xfer))
867                         continue;
868
869                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
870                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
871         }
872
873         return 0;
874 }
875 #else /* !CONFIG_HAS_DMA */
876 static inline int spi_map_buf(struct spi_master *master,
877                               struct device *dev, struct sg_table *sgt,
878                               void *buf, size_t len,
879                               enum dma_data_direction dir)
880 {
881         return -EINVAL;
882 }
883
884 static inline void spi_unmap_buf(struct spi_master *master,
885                                  struct device *dev, struct sg_table *sgt,
886                                  enum dma_data_direction dir)
887 {
888 }
889
890 static inline int __spi_map_msg(struct spi_master *master,
891                                 struct spi_message *msg)
892 {
893         return 0;
894 }
895
896 static inline int __spi_unmap_msg(struct spi_master *master,
897                                   struct spi_message *msg)
898 {
899         return 0;
900 }
901 #endif /* !CONFIG_HAS_DMA */
902
903 static inline int spi_unmap_msg(struct spi_master *master,
904                                 struct spi_message *msg)
905 {
906         struct spi_transfer *xfer;
907
908         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
909                 /*
910                  * Restore the original value of tx_buf or rx_buf if they are
911                  * NULL.
912                  */
913                 if (xfer->tx_buf == master->dummy_tx)
914                         xfer->tx_buf = NULL;
915                 if (xfer->rx_buf == master->dummy_rx)
916                         xfer->rx_buf = NULL;
917         }
918
919         return __spi_unmap_msg(master, msg);
920 }
921
922 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
923 {
924         struct spi_transfer *xfer;
925         void *tmp;
926         unsigned int max_tx, max_rx;
927
928         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
929                 max_tx = 0;
930                 max_rx = 0;
931
932                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
933                         if ((master->flags & SPI_MASTER_MUST_TX) &&
934                             !xfer->tx_buf)
935                                 max_tx = max(xfer->len, max_tx);
936                         if ((master->flags & SPI_MASTER_MUST_RX) &&
937                             !xfer->rx_buf)
938                                 max_rx = max(xfer->len, max_rx);
939                 }
940
941                 if (max_tx) {
942                         tmp = krealloc(master->dummy_tx, max_tx,
943                                        GFP_KERNEL | GFP_DMA);
944                         if (!tmp)
945                                 return -ENOMEM;
946                         master->dummy_tx = tmp;
947                         memset(tmp, 0, max_tx);
948                 }
949
950                 if (max_rx) {
951                         tmp = krealloc(master->dummy_rx, max_rx,
952                                        GFP_KERNEL | GFP_DMA);
953                         if (!tmp)
954                                 return -ENOMEM;
955                         master->dummy_rx = tmp;
956                 }
957
958                 if (max_tx || max_rx) {
959                         list_for_each_entry(xfer, &msg->transfers,
960                                             transfer_list) {
961                                 if (!xfer->tx_buf)
962                                         xfer->tx_buf = master->dummy_tx;
963                                 if (!xfer->rx_buf)
964                                         xfer->rx_buf = master->dummy_rx;
965                         }
966                 }
967         }
968
969         return __spi_map_msg(master, msg);
970 }
971
972 /*
973  * spi_transfer_one_message - Default implementation of transfer_one_message()
974  *
975  * This is a standard implementation of transfer_one_message() for
976  * drivers which implement a transfer_one() operation.  It provides
977  * standard handling of delays and chip select management.
978  */
979 static int spi_transfer_one_message(struct spi_master *master,
980                                     struct spi_message *msg)
981 {
982         struct spi_transfer *xfer;
983         bool keep_cs = false;
984         int ret = 0;
985         unsigned long long ms = 1;
986         struct spi_statistics *statm = &master->statistics;
987         struct spi_statistics *stats = &msg->spi->statistics;
988
989         spi_set_cs(msg->spi, true);
990
991         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
992         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
993
994         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
995                 trace_spi_transfer_start(msg, xfer);
996
997                 spi_statistics_add_transfer_stats(statm, xfer, master);
998                 spi_statistics_add_transfer_stats(stats, xfer, master);
999
1000                 if (xfer->tx_buf || xfer->rx_buf) {
1001                         reinit_completion(&master->xfer_completion);
1002
1003                         ret = master->transfer_one(master, msg->spi, xfer);
1004                         if (ret < 0) {
1005                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1006                                                                errors);
1007                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1008                                                                errors);
1009                                 dev_err(&msg->spi->dev,
1010                                         "SPI transfer failed: %d\n", ret);
1011                                 goto out;
1012                         }
1013
1014                         if (ret > 0) {
1015                                 ret = 0;
1016                                 ms = 8LL * 1000LL * xfer->len;
1017                                 do_div(ms, xfer->speed_hz);
1018                                 ms += ms + 200; /* some tolerance */
1019
1020                                 if (ms > UINT_MAX)
1021                                         ms = UINT_MAX;
1022
1023                                 ms = wait_for_completion_timeout(&master->xfer_completion,
1024                                                                  msecs_to_jiffies(ms));
1025                         }
1026
1027                         if (ms == 0) {
1028                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1029                                                                timedout);
1030                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1031                                                                timedout);
1032                                 dev_err(&msg->spi->dev,
1033                                         "SPI transfer timed out\n");
1034                                 msg->status = -ETIMEDOUT;
1035                         }
1036                 } else {
1037                         if (xfer->len)
1038                                 dev_err(&msg->spi->dev,
1039                                         "Bufferless transfer has length %u\n",
1040                                         xfer->len);
1041                 }
1042
1043                 trace_spi_transfer_stop(msg, xfer);
1044
1045                 if (msg->status != -EINPROGRESS)
1046                         goto out;
1047
1048                 if (xfer->delay_usecs) {
1049                         u16 us = xfer->delay_usecs;
1050
1051                         if (us <= 10)
1052                                 udelay(us);
1053                         else
1054                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1055                 }
1056
1057                 if (xfer->cs_change) {
1058                         if (list_is_last(&xfer->transfer_list,
1059                                          &msg->transfers)) {
1060                                 keep_cs = true;
1061                         } else {
1062                                 spi_set_cs(msg->spi, false);
1063                                 udelay(10);
1064                                 spi_set_cs(msg->spi, true);
1065                         }
1066                 }
1067
1068                 msg->actual_length += xfer->len;
1069         }
1070
1071 out:
1072         if (ret != 0 || !keep_cs)
1073                 spi_set_cs(msg->spi, false);
1074
1075         if (msg->status == -EINPROGRESS)
1076                 msg->status = ret;
1077
1078         if (msg->status && master->handle_err)
1079                 master->handle_err(master, msg);
1080
1081         spi_res_release(master, msg);
1082
1083         spi_finalize_current_message(master);
1084
1085         return ret;
1086 }
1087
1088 /**
1089  * spi_finalize_current_transfer - report completion of a transfer
1090  * @master: the master reporting completion
1091  *
1092  * Called by SPI drivers using the core transfer_one_message()
1093  * implementation to notify it that the current interrupt driven
1094  * transfer has finished and the next one may be scheduled.
1095  */
1096 void spi_finalize_current_transfer(struct spi_master *master)
1097 {
1098         complete(&master->xfer_completion);
1099 }
1100 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1101
1102 /**
1103  * __spi_pump_messages - function which processes spi message queue
1104  * @master: master to process queue for
1105  * @in_kthread: true if we are in the context of the message pump thread
1106  *
1107  * This function checks if there is any spi message in the queue that
1108  * needs processing and if so call out to the driver to initialize hardware
1109  * and transfer each message.
1110  *
1111  * Note that it is called both from the kthread itself and also from
1112  * inside spi_sync(); the queue extraction handling at the top of the
1113  * function should deal with this safely.
1114  */
1115 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1116 {
1117         unsigned long flags;
1118         bool was_busy = false;
1119         int ret;
1120
1121         /* Lock queue */
1122         spin_lock_irqsave(&master->queue_lock, flags);
1123
1124         /* Make sure we are not already running a message */
1125         if (master->cur_msg) {
1126                 spin_unlock_irqrestore(&master->queue_lock, flags);
1127                 return;
1128         }
1129
1130         /* If another context is idling the device then defer */
1131         if (master->idling) {
1132                 kthread_queue_work(&master->kworker, &master->pump_messages);
1133                 spin_unlock_irqrestore(&master->queue_lock, flags);
1134                 return;
1135         }
1136
1137         /* Check if the queue is idle */
1138         if (list_empty(&master->queue) || !master->running) {
1139                 if (!master->busy) {
1140                         spin_unlock_irqrestore(&master->queue_lock, flags);
1141                         return;
1142                 }
1143
1144                 /* Only do teardown in the thread */
1145                 if (!in_kthread) {
1146                         kthread_queue_work(&master->kworker,
1147                                            &master->pump_messages);
1148                         spin_unlock_irqrestore(&master->queue_lock, flags);
1149                         return;
1150                 }
1151
1152                 master->busy = false;
1153                 master->idling = true;
1154                 spin_unlock_irqrestore(&master->queue_lock, flags);
1155
1156                 kfree(master->dummy_rx);
1157                 master->dummy_rx = NULL;
1158                 kfree(master->dummy_tx);
1159                 master->dummy_tx = NULL;
1160                 if (master->unprepare_transfer_hardware &&
1161                     master->unprepare_transfer_hardware(master))
1162                         dev_err(&master->dev,
1163                                 "failed to unprepare transfer hardware\n");
1164                 if (master->auto_runtime_pm) {
1165                         pm_runtime_mark_last_busy(master->dev.parent);
1166                         pm_runtime_put_autosuspend(master->dev.parent);
1167                 }
1168                 trace_spi_master_idle(master);
1169
1170                 spin_lock_irqsave(&master->queue_lock, flags);
1171                 master->idling = false;
1172                 spin_unlock_irqrestore(&master->queue_lock, flags);
1173                 return;
1174         }
1175
1176         /* Extract head of queue */
1177         master->cur_msg =
1178                 list_first_entry(&master->queue, struct spi_message, queue);
1179
1180         list_del_init(&master->cur_msg->queue);
1181         if (master->busy)
1182                 was_busy = true;
1183         else
1184                 master->busy = true;
1185         spin_unlock_irqrestore(&master->queue_lock, flags);
1186
1187         mutex_lock(&master->io_mutex);
1188
1189         if (!was_busy && master->auto_runtime_pm) {
1190                 ret = pm_runtime_get_sync(master->dev.parent);
1191                 if (ret < 0) {
1192                         dev_err(&master->dev, "Failed to power device: %d\n",
1193                                 ret);
1194                         mutex_unlock(&master->io_mutex);
1195                         return;
1196                 }
1197         }
1198
1199         if (!was_busy)
1200                 trace_spi_master_busy(master);
1201
1202         if (!was_busy && master->prepare_transfer_hardware) {
1203                 ret = master->prepare_transfer_hardware(master);
1204                 if (ret) {
1205                         dev_err(&master->dev,
1206                                 "failed to prepare transfer hardware\n");
1207
1208                         if (master->auto_runtime_pm)
1209                                 pm_runtime_put(master->dev.parent);
1210                         mutex_unlock(&master->io_mutex);
1211                         return;
1212                 }
1213         }
1214
1215         trace_spi_message_start(master->cur_msg);
1216
1217         if (master->prepare_message) {
1218                 ret = master->prepare_message(master, master->cur_msg);
1219                 if (ret) {
1220                         dev_err(&master->dev,
1221                                 "failed to prepare message: %d\n", ret);
1222                         master->cur_msg->status = ret;
1223                         spi_finalize_current_message(master);
1224                         goto out;
1225                 }
1226                 master->cur_msg_prepared = true;
1227         }
1228
1229         ret = spi_map_msg(master, master->cur_msg);
1230         if (ret) {
1231                 master->cur_msg->status = ret;
1232                 spi_finalize_current_message(master);
1233                 goto out;
1234         }
1235
1236         ret = master->transfer_one_message(master, master->cur_msg);
1237         if (ret) {
1238                 dev_err(&master->dev,
1239                         "failed to transfer one message from queue\n");
1240                 goto out;
1241         }
1242
1243 out:
1244         mutex_unlock(&master->io_mutex);
1245
1246         /* Prod the scheduler in case transfer_one() was busy waiting */
1247         if (!ret)
1248                 cond_resched();
1249 }
1250
1251 /**
1252  * spi_pump_messages - kthread work function which processes spi message queue
1253  * @work: pointer to kthread work struct contained in the master struct
1254  */
1255 static void spi_pump_messages(struct kthread_work *work)
1256 {
1257         struct spi_master *master =
1258                 container_of(work, struct spi_master, pump_messages);
1259
1260         __spi_pump_messages(master, true);
1261 }
1262
1263 static int spi_init_queue(struct spi_master *master)
1264 {
1265         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1266
1267         master->running = false;
1268         master->busy = false;
1269
1270         kthread_init_worker(&master->kworker);
1271         master->kworker_task = kthread_run(kthread_worker_fn,
1272                                            &master->kworker, "%s",
1273                                            dev_name(&master->dev));
1274         if (IS_ERR(master->kworker_task)) {
1275                 dev_err(&master->dev, "failed to create message pump task\n");
1276                 return PTR_ERR(master->kworker_task);
1277         }
1278         kthread_init_work(&master->pump_messages, spi_pump_messages);
1279
1280         /*
1281          * Master config will indicate if this controller should run the
1282          * message pump with high (realtime) priority to reduce the transfer
1283          * latency on the bus by minimising the delay between a transfer
1284          * request and the scheduling of the message pump thread. Without this
1285          * setting the message pump thread will remain at default priority.
1286          */
1287         if (master->rt) {
1288                 dev_info(&master->dev,
1289                         "will run message pump with realtime priority\n");
1290                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1291         }
1292
1293         return 0;
1294 }
1295
1296 /**
1297  * spi_get_next_queued_message() - called by driver to check for queued
1298  * messages
1299  * @master: the master to check for queued messages
1300  *
1301  * If there are more messages in the queue, the next message is returned from
1302  * this call.
1303  *
1304  * Return: the next message in the queue, else NULL if the queue is empty.
1305  */
1306 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1307 {
1308         struct spi_message *next;
1309         unsigned long flags;
1310
1311         /* get a pointer to the next message, if any */
1312         spin_lock_irqsave(&master->queue_lock, flags);
1313         next = list_first_entry_or_null(&master->queue, struct spi_message,
1314                                         queue);
1315         spin_unlock_irqrestore(&master->queue_lock, flags);
1316
1317         return next;
1318 }
1319 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1320
1321 /**
1322  * spi_finalize_current_message() - the current message is complete
1323  * @master: the master to return the message to
1324  *
1325  * Called by the driver to notify the core that the message in the front of the
1326  * queue is complete and can be removed from the queue.
1327  */
1328 void spi_finalize_current_message(struct spi_master *master)
1329 {
1330         struct spi_message *mesg;
1331         unsigned long flags;
1332         int ret;
1333
1334         spin_lock_irqsave(&master->queue_lock, flags);
1335         mesg = master->cur_msg;
1336         spin_unlock_irqrestore(&master->queue_lock, flags);
1337
1338         spi_unmap_msg(master, mesg);
1339
1340         if (master->cur_msg_prepared && master->unprepare_message) {
1341                 ret = master->unprepare_message(master, mesg);
1342                 if (ret) {
1343                         dev_err(&master->dev,
1344                                 "failed to unprepare message: %d\n", ret);
1345                 }
1346         }
1347
1348         spin_lock_irqsave(&master->queue_lock, flags);
1349         master->cur_msg = NULL;
1350         master->cur_msg_prepared = false;
1351         kthread_queue_work(&master->kworker, &master->pump_messages);
1352         spin_unlock_irqrestore(&master->queue_lock, flags);
1353
1354         trace_spi_message_done(mesg);
1355
1356         mesg->state = NULL;
1357         if (mesg->complete)
1358                 mesg->complete(mesg->context);
1359 }
1360 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1361
1362 static int spi_start_queue(struct spi_master *master)
1363 {
1364         unsigned long flags;
1365
1366         spin_lock_irqsave(&master->queue_lock, flags);
1367
1368         if (master->running || master->busy) {
1369                 spin_unlock_irqrestore(&master->queue_lock, flags);
1370                 return -EBUSY;
1371         }
1372
1373         master->running = true;
1374         master->cur_msg = NULL;
1375         spin_unlock_irqrestore(&master->queue_lock, flags);
1376
1377         kthread_queue_work(&master->kworker, &master->pump_messages);
1378
1379         return 0;
1380 }
1381
1382 static int spi_stop_queue(struct spi_master *master)
1383 {
1384         unsigned long flags;
1385         unsigned limit = 500;
1386         int ret = 0;
1387
1388         spin_lock_irqsave(&master->queue_lock, flags);
1389
1390         /*
1391          * This is a bit lame, but is optimized for the common execution path.
1392          * A wait_queue on the master->busy could be used, but then the common
1393          * execution path (pump_messages) would be required to call wake_up or
1394          * friends on every SPI message. Do this instead.
1395          */
1396         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1397                 spin_unlock_irqrestore(&master->queue_lock, flags);
1398                 usleep_range(10000, 11000);
1399                 spin_lock_irqsave(&master->queue_lock, flags);
1400         }
1401
1402         if (!list_empty(&master->queue) || master->busy)
1403                 ret = -EBUSY;
1404         else
1405                 master->running = false;
1406
1407         spin_unlock_irqrestore(&master->queue_lock, flags);
1408
1409         if (ret) {
1410                 dev_warn(&master->dev,
1411                          "could not stop message queue\n");
1412                 return ret;
1413         }
1414         return ret;
1415 }
1416
1417 static int spi_destroy_queue(struct spi_master *master)
1418 {
1419         int ret;
1420
1421         ret = spi_stop_queue(master);
1422
1423         /*
1424          * kthread_flush_worker will block until all work is done.
1425          * If the reason that stop_queue timed out is that the work will never
1426          * finish, then it does no good to call flush/stop thread, so
1427          * return anyway.
1428          */
1429         if (ret) {
1430                 dev_err(&master->dev, "problem destroying queue\n");
1431                 return ret;
1432         }
1433
1434         kthread_flush_worker(&master->kworker);
1435         kthread_stop(master->kworker_task);
1436
1437         return 0;
1438 }
1439
1440 static int __spi_queued_transfer(struct spi_device *spi,
1441                                  struct spi_message *msg,
1442                                  bool need_pump)
1443 {
1444         struct spi_master *master = spi->master;
1445         unsigned long flags;
1446
1447         spin_lock_irqsave(&master->queue_lock, flags);
1448
1449         if (!master->running) {
1450                 spin_unlock_irqrestore(&master->queue_lock, flags);
1451                 return -ESHUTDOWN;
1452         }
1453         msg->actual_length = 0;
1454         msg->status = -EINPROGRESS;
1455
1456         list_add_tail(&msg->queue, &master->queue);
1457         if (!master->busy && need_pump)
1458                 kthread_queue_work(&master->kworker, &master->pump_messages);
1459
1460         spin_unlock_irqrestore(&master->queue_lock, flags);
1461         return 0;
1462 }
1463
1464 /**
1465  * spi_queued_transfer - transfer function for queued transfers
1466  * @spi: spi device which is requesting transfer
1467  * @msg: spi message which is to handled is queued to driver queue
1468  *
1469  * Return: zero on success, else a negative error code.
1470  */
1471 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1472 {
1473         return __spi_queued_transfer(spi, msg, true);
1474 }
1475
1476 static int spi_master_initialize_queue(struct spi_master *master)
1477 {
1478         int ret;
1479
1480         master->transfer = spi_queued_transfer;
1481         if (!master->transfer_one_message)
1482                 master->transfer_one_message = spi_transfer_one_message;
1483
1484         /* Initialize and start queue */
1485         ret = spi_init_queue(master);
1486         if (ret) {
1487                 dev_err(&master->dev, "problem initializing queue\n");
1488                 goto err_init_queue;
1489         }
1490         master->queued = true;
1491         ret = spi_start_queue(master);
1492         if (ret) {
1493                 dev_err(&master->dev, "problem starting queue\n");
1494                 goto err_start_queue;
1495         }
1496
1497         return 0;
1498
1499 err_start_queue:
1500         spi_destroy_queue(master);
1501 err_init_queue:
1502         return ret;
1503 }
1504
1505 /*-------------------------------------------------------------------------*/
1506
1507 #if defined(CONFIG_OF)
1508 static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi,
1509                            struct device_node *nc)
1510 {
1511         u32 value;
1512         int rc;
1513
1514         /* Device address */
1515         rc = of_property_read_u32(nc, "reg", &value);
1516         if (rc) {
1517                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1518                         nc->full_name, rc);
1519                 return rc;
1520         }
1521         spi->chip_select = value;
1522
1523         /* Mode (clock phase/polarity/etc.) */
1524         if (of_find_property(nc, "spi-cpha", NULL))
1525                 spi->mode |= SPI_CPHA;
1526         if (of_find_property(nc, "spi-cpol", NULL))
1527                 spi->mode |= SPI_CPOL;
1528         if (of_find_property(nc, "spi-cs-high", NULL))
1529                 spi->mode |= SPI_CS_HIGH;
1530         if (of_find_property(nc, "spi-3wire", NULL))
1531                 spi->mode |= SPI_3WIRE;
1532         if (of_find_property(nc, "spi-lsb-first", NULL))
1533                 spi->mode |= SPI_LSB_FIRST;
1534
1535         /* Device DUAL/QUAD mode */
1536         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1537                 switch (value) {
1538                 case 1:
1539                         break;
1540                 case 2:
1541                         spi->mode |= SPI_TX_DUAL;
1542                         break;
1543                 case 4:
1544                         spi->mode |= SPI_TX_QUAD;
1545                         break;
1546                 default:
1547                         dev_warn(&master->dev,
1548                                 "spi-tx-bus-width %d not supported\n",
1549                                 value);
1550                         break;
1551                 }
1552         }
1553
1554         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1555                 switch (value) {
1556                 case 1:
1557                         break;
1558                 case 2:
1559                         spi->mode |= SPI_RX_DUAL;
1560                         break;
1561                 case 4:
1562                         spi->mode |= SPI_RX_QUAD;
1563                         break;
1564                 default:
1565                         dev_warn(&master->dev,
1566                                 "spi-rx-bus-width %d not supported\n",
1567                                 value);
1568                         break;
1569                 }
1570         }
1571
1572         /* Device speed */
1573         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1574         if (rc) {
1575                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1576                         nc->full_name, rc);
1577                 return rc;
1578         }
1579         spi->max_speed_hz = value;
1580
1581         return 0;
1582 }
1583
1584 static struct spi_device *
1585 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1586 {
1587         struct spi_device *spi;
1588         int rc;
1589
1590         /* Alloc an spi_device */
1591         spi = spi_alloc_device(master);
1592         if (!spi) {
1593                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1594                         nc->full_name);
1595                 rc = -ENOMEM;
1596                 goto err_out;
1597         }
1598
1599         /* Select device driver */
1600         rc = of_modalias_node(nc, spi->modalias,
1601                                 sizeof(spi->modalias));
1602         if (rc < 0) {
1603                 dev_err(&master->dev, "cannot find modalias for %s\n",
1604                         nc->full_name);
1605                 goto err_out;
1606         }
1607
1608         rc = of_spi_parse_dt(master, spi, nc);
1609         if (rc)
1610                 goto err_out;
1611
1612         /* Store a pointer to the node in the device structure */
1613         of_node_get(nc);
1614         spi->dev.of_node = nc;
1615
1616         /* Register the new device */
1617         rc = spi_add_device(spi);
1618         if (rc) {
1619                 dev_err(&master->dev, "spi_device register error %s\n",
1620                         nc->full_name);
1621                 goto err_of_node_put;
1622         }
1623
1624         return spi;
1625
1626 err_of_node_put:
1627         of_node_put(nc);
1628 err_out:
1629         spi_dev_put(spi);
1630         return ERR_PTR(rc);
1631 }
1632
1633 /**
1634  * of_register_spi_devices() - Register child devices onto the SPI bus
1635  * @master:     Pointer to spi_master device
1636  *
1637  * Registers an spi_device for each child node of master node which has a 'reg'
1638  * property.
1639  */
1640 static void of_register_spi_devices(struct spi_master *master)
1641 {
1642         struct spi_device *spi;
1643         struct device_node *nc;
1644
1645         if (!master->dev.of_node)
1646                 return;
1647
1648         for_each_available_child_of_node(master->dev.of_node, nc) {
1649                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1650                         continue;
1651                 spi = of_register_spi_device(master, nc);
1652                 if (IS_ERR(spi)) {
1653                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1654                                 nc->full_name);
1655                         of_node_clear_flag(nc, OF_POPULATED);
1656                 }
1657         }
1658 }
1659 #else
1660 static void of_register_spi_devices(struct spi_master *master) { }
1661 #endif
1662
1663 #ifdef CONFIG_ACPI
1664 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1665 {
1666         struct spi_device *spi = data;
1667         struct spi_master *master = spi->master;
1668
1669         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1670                 struct acpi_resource_spi_serialbus *sb;
1671
1672                 sb = &ares->data.spi_serial_bus;
1673                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1674                         /*
1675                          * ACPI DeviceSelection numbering is handled by the
1676                          * host controller driver in Windows and can vary
1677                          * from driver to driver. In Linux we always expect
1678                          * 0 .. max - 1 so we need to ask the driver to
1679                          * translate between the two schemes.
1680                          */
1681                         if (master->fw_translate_cs) {
1682                                 int cs = master->fw_translate_cs(master,
1683                                                 sb->device_selection);
1684                                 if (cs < 0)
1685                                         return cs;
1686                                 spi->chip_select = cs;
1687                         } else {
1688                                 spi->chip_select = sb->device_selection;
1689                         }
1690
1691                         spi->max_speed_hz = sb->connection_speed;
1692
1693                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1694                                 spi->mode |= SPI_CPHA;
1695                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1696                                 spi->mode |= SPI_CPOL;
1697                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1698                                 spi->mode |= SPI_CS_HIGH;
1699                 }
1700         } else if (spi->irq < 0) {
1701                 struct resource r;
1702
1703                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1704                         spi->irq = r.start;
1705         }
1706
1707         /* Always tell the ACPI core to skip this resource */
1708         return 1;
1709 }
1710
1711 static acpi_status acpi_register_spi_device(struct spi_master *master,
1712                                             struct acpi_device *adev)
1713 {
1714         struct list_head resource_list;
1715         struct spi_device *spi;
1716         int ret;
1717
1718         if (acpi_bus_get_status(adev) || !adev->status.present ||
1719             acpi_device_enumerated(adev))
1720                 return AE_OK;
1721
1722         spi = spi_alloc_device(master);
1723         if (!spi) {
1724                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1725                         dev_name(&adev->dev));
1726                 return AE_NO_MEMORY;
1727         }
1728
1729         ACPI_COMPANION_SET(&spi->dev, adev);
1730         spi->irq = -1;
1731
1732         INIT_LIST_HEAD(&resource_list);
1733         ret = acpi_dev_get_resources(adev, &resource_list,
1734                                      acpi_spi_add_resource, spi);
1735         acpi_dev_free_resource_list(&resource_list);
1736
1737         if (ret < 0 || !spi->max_speed_hz) {
1738                 spi_dev_put(spi);
1739                 return AE_OK;
1740         }
1741
1742         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1743                           sizeof(spi->modalias));
1744
1745         if (spi->irq < 0)
1746                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1747
1748         acpi_device_set_enumerated(adev);
1749
1750         adev->power.flags.ignore_parent = true;
1751         if (spi_add_device(spi)) {
1752                 adev->power.flags.ignore_parent = false;
1753                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1754                         dev_name(&adev->dev));
1755                 spi_dev_put(spi);
1756         }
1757
1758         return AE_OK;
1759 }
1760
1761 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1762                                        void *data, void **return_value)
1763 {
1764         struct spi_master *master = data;
1765         struct acpi_device *adev;
1766
1767         if (acpi_bus_get_device(handle, &adev))
1768                 return AE_OK;
1769
1770         return acpi_register_spi_device(master, adev);
1771 }
1772
1773 static void acpi_register_spi_devices(struct spi_master *master)
1774 {
1775         acpi_status status;
1776         acpi_handle handle;
1777
1778         handle = ACPI_HANDLE(master->dev.parent);
1779         if (!handle)
1780                 return;
1781
1782         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1783                                      acpi_spi_add_device, NULL,
1784                                      master, NULL);
1785         if (ACPI_FAILURE(status))
1786                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1787 }
1788 #else
1789 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1790 #endif /* CONFIG_ACPI */
1791
1792 static void spi_master_release(struct device *dev)
1793 {
1794         struct spi_master *master;
1795
1796         master = container_of(dev, struct spi_master, dev);
1797         kfree(master);
1798 }
1799
1800 static struct class spi_master_class = {
1801         .name           = "spi_master",
1802         .owner          = THIS_MODULE,
1803         .dev_release    = spi_master_release,
1804         .dev_groups     = spi_master_groups,
1805 };
1806
1807
1808 /**
1809  * spi_alloc_master - allocate SPI master controller
1810  * @dev: the controller, possibly using the platform_bus
1811  * @size: how much zeroed driver-private data to allocate; the pointer to this
1812  *      memory is in the driver_data field of the returned device,
1813  *      accessible with spi_master_get_devdata().
1814  * Context: can sleep
1815  *
1816  * This call is used only by SPI master controller drivers, which are the
1817  * only ones directly touching chip registers.  It's how they allocate
1818  * an spi_master structure, prior to calling spi_register_master().
1819  *
1820  * This must be called from context that can sleep.
1821  *
1822  * The caller is responsible for assigning the bus number and initializing
1823  * the master's methods before calling spi_register_master(); and (after errors
1824  * adding the device) calling spi_master_put() to prevent a memory leak.
1825  *
1826  * Return: the SPI master structure on success, else NULL.
1827  */
1828 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1829 {
1830         struct spi_master       *master;
1831
1832         if (!dev)
1833                 return NULL;
1834
1835         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1836         if (!master)
1837                 return NULL;
1838
1839         device_initialize(&master->dev);
1840         master->bus_num = -1;
1841         master->num_chipselect = 1;
1842         master->dev.class = &spi_master_class;
1843         master->dev.parent = dev;
1844         pm_suspend_ignore_children(&master->dev, true);
1845         spi_master_set_devdata(master, &master[1]);
1846
1847         return master;
1848 }
1849 EXPORT_SYMBOL_GPL(spi_alloc_master);
1850
1851 #ifdef CONFIG_OF
1852 static int of_spi_register_master(struct spi_master *master)
1853 {
1854         int nb, i, *cs;
1855         struct device_node *np = master->dev.of_node;
1856
1857         if (!np)
1858                 return 0;
1859
1860         nb = of_gpio_named_count(np, "cs-gpios");
1861         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1862
1863         /* Return error only for an incorrectly formed cs-gpios property */
1864         if (nb == 0 || nb == -ENOENT)
1865                 return 0;
1866         else if (nb < 0)
1867                 return nb;
1868
1869         cs = devm_kzalloc(&master->dev,
1870                           sizeof(int) * master->num_chipselect,
1871                           GFP_KERNEL);
1872         master->cs_gpios = cs;
1873
1874         if (!master->cs_gpios)
1875                 return -ENOMEM;
1876
1877         for (i = 0; i < master->num_chipselect; i++)
1878                 cs[i] = -ENOENT;
1879
1880         for (i = 0; i < nb; i++)
1881                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1882
1883         return 0;
1884 }
1885 #else
1886 static int of_spi_register_master(struct spi_master *master)
1887 {
1888         return 0;
1889 }
1890 #endif
1891
1892 /**
1893  * spi_register_master - register SPI master controller
1894  * @master: initialized master, originally from spi_alloc_master()
1895  * Context: can sleep
1896  *
1897  * SPI master controllers connect to their drivers using some non-SPI bus,
1898  * such as the platform bus.  The final stage of probe() in that code
1899  * includes calling spi_register_master() to hook up to this SPI bus glue.
1900  *
1901  * SPI controllers use board specific (often SOC specific) bus numbers,
1902  * and board-specific addressing for SPI devices combines those numbers
1903  * with chip select numbers.  Since SPI does not directly support dynamic
1904  * device identification, boards need configuration tables telling which
1905  * chip is at which address.
1906  *
1907  * This must be called from context that can sleep.  It returns zero on
1908  * success, else a negative error code (dropping the master's refcount).
1909  * After a successful return, the caller is responsible for calling
1910  * spi_unregister_master().
1911  *
1912  * Return: zero on success, else a negative error code.
1913  */
1914 int spi_register_master(struct spi_master *master)
1915 {
1916         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1917         struct device           *dev = master->dev.parent;
1918         struct boardinfo        *bi;
1919         int                     status = -ENODEV;
1920         int                     dynamic = 0;
1921
1922         if (!dev)
1923                 return -ENODEV;
1924
1925         status = of_spi_register_master(master);
1926         if (status)
1927                 return status;
1928
1929         /* even if it's just one always-selected device, there must
1930          * be at least one chipselect
1931          */
1932         if (master->num_chipselect == 0)
1933                 return -EINVAL;
1934
1935         if ((master->bus_num < 0) && master->dev.of_node)
1936                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1937
1938         /* convention:  dynamically assigned bus IDs count down from the max */
1939         if (master->bus_num < 0) {
1940                 /* FIXME switch to an IDR based scheme, something like
1941                  * I2C now uses, so we can't run out of "dynamic" IDs
1942                  */
1943                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1944                 dynamic = 1;
1945         }
1946
1947         INIT_LIST_HEAD(&master->queue);
1948         spin_lock_init(&master->queue_lock);
1949         spin_lock_init(&master->bus_lock_spinlock);
1950         mutex_init(&master->bus_lock_mutex);
1951         mutex_init(&master->io_mutex);
1952         master->bus_lock_flag = 0;
1953         init_completion(&master->xfer_completion);
1954         if (!master->max_dma_len)
1955                 master->max_dma_len = INT_MAX;
1956
1957         /* register the device, then userspace will see it.
1958          * registration fails if the bus ID is in use.
1959          */
1960         dev_set_name(&master->dev, "spi%u", master->bus_num);
1961         status = device_add(&master->dev);
1962         if (status < 0)
1963                 goto done;
1964         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1965                         dynamic ? " (dynamic)" : "");
1966
1967         /* If we're using a queued driver, start the queue */
1968         if (master->transfer)
1969                 dev_info(dev, "master is unqueued, this is deprecated\n");
1970         else {
1971                 status = spi_master_initialize_queue(master);
1972                 if (status) {
1973                         device_del(&master->dev);
1974                         goto done;
1975                 }
1976         }
1977         /* add statistics */
1978         spin_lock_init(&master->statistics.lock);
1979
1980         mutex_lock(&board_lock);
1981         list_add_tail(&master->list, &spi_master_list);
1982         list_for_each_entry(bi, &board_list, list)
1983                 spi_match_master_to_boardinfo(master, &bi->board_info);
1984         mutex_unlock(&board_lock);
1985
1986         /* Register devices from the device tree and ACPI */
1987         of_register_spi_devices(master);
1988         acpi_register_spi_devices(master);
1989 done:
1990         return status;
1991 }
1992 EXPORT_SYMBOL_GPL(spi_register_master);
1993
1994 static void devm_spi_unregister(struct device *dev, void *res)
1995 {
1996         spi_unregister_master(*(struct spi_master **)res);
1997 }
1998
1999 /**
2000  * dev_spi_register_master - register managed SPI master controller
2001  * @dev:    device managing SPI master
2002  * @master: initialized master, originally from spi_alloc_master()
2003  * Context: can sleep
2004  *
2005  * Register a SPI device as with spi_register_master() which will
2006  * automatically be unregister
2007  *
2008  * Return: zero on success, else a negative error code.
2009  */
2010 int devm_spi_register_master(struct device *dev, struct spi_master *master)
2011 {
2012         struct spi_master **ptr;
2013         int ret;
2014
2015         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2016         if (!ptr)
2017                 return -ENOMEM;
2018
2019         ret = spi_register_master(master);
2020         if (!ret) {
2021                 *ptr = master;
2022                 devres_add(dev, ptr);
2023         } else {
2024                 devres_free(ptr);
2025         }
2026
2027         return ret;
2028 }
2029 EXPORT_SYMBOL_GPL(devm_spi_register_master);
2030
2031 static int __unregister(struct device *dev, void *null)
2032 {
2033         spi_unregister_device(to_spi_device(dev));
2034         return 0;
2035 }
2036
2037 /**
2038  * spi_unregister_master - unregister SPI master controller
2039  * @master: the master being unregistered
2040  * Context: can sleep
2041  *
2042  * This call is used only by SPI master controller drivers, which are the
2043  * only ones directly touching chip registers.
2044  *
2045  * This must be called from context that can sleep.
2046  */
2047 void spi_unregister_master(struct spi_master *master)
2048 {
2049         int dummy;
2050
2051         if (master->queued) {
2052                 if (spi_destroy_queue(master))
2053                         dev_err(&master->dev, "queue remove failed\n");
2054         }
2055
2056         mutex_lock(&board_lock);
2057         list_del(&master->list);
2058         mutex_unlock(&board_lock);
2059
2060         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2061         device_unregister(&master->dev);
2062 }
2063 EXPORT_SYMBOL_GPL(spi_unregister_master);
2064
2065 int spi_master_suspend(struct spi_master *master)
2066 {
2067         int ret;
2068
2069         /* Basically no-ops for non-queued masters */
2070         if (!master->queued)
2071                 return 0;
2072
2073         ret = spi_stop_queue(master);
2074         if (ret)
2075                 dev_err(&master->dev, "queue stop failed\n");
2076
2077         return ret;
2078 }
2079 EXPORT_SYMBOL_GPL(spi_master_suspend);
2080
2081 int spi_master_resume(struct spi_master *master)
2082 {
2083         int ret;
2084
2085         if (!master->queued)
2086                 return 0;
2087
2088         ret = spi_start_queue(master);
2089         if (ret)
2090                 dev_err(&master->dev, "queue restart failed\n");
2091
2092         return ret;
2093 }
2094 EXPORT_SYMBOL_GPL(spi_master_resume);
2095
2096 static int __spi_master_match(struct device *dev, const void *data)
2097 {
2098         struct spi_master *m;
2099         const u16 *bus_num = data;
2100
2101         m = container_of(dev, struct spi_master, dev);
2102         return m->bus_num == *bus_num;
2103 }
2104
2105 /**
2106  * spi_busnum_to_master - look up master associated with bus_num
2107  * @bus_num: the master's bus number
2108  * Context: can sleep
2109  *
2110  * This call may be used with devices that are registered after
2111  * arch init time.  It returns a refcounted pointer to the relevant
2112  * spi_master (which the caller must release), or NULL if there is
2113  * no such master registered.
2114  *
2115  * Return: the SPI master structure on success, else NULL.
2116  */
2117 struct spi_master *spi_busnum_to_master(u16 bus_num)
2118 {
2119         struct device           *dev;
2120         struct spi_master       *master = NULL;
2121
2122         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2123                                 __spi_master_match);
2124         if (dev)
2125                 master = container_of(dev, struct spi_master, dev);
2126         /* reference got in class_find_device */
2127         return master;
2128 }
2129 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2130
2131 /*-------------------------------------------------------------------------*/
2132
2133 /* Core methods for SPI resource management */
2134
2135 /**
2136  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2137  *                 during the processing of a spi_message while using
2138  *                 spi_transfer_one
2139  * @spi:     the spi device for which we allocate memory
2140  * @release: the release code to execute for this resource
2141  * @size:    size to alloc and return
2142  * @gfp:     GFP allocation flags
2143  *
2144  * Return: the pointer to the allocated data
2145  *
2146  * This may get enhanced in the future to allocate from a memory pool
2147  * of the @spi_device or @spi_master to avoid repeated allocations.
2148  */
2149 void *spi_res_alloc(struct spi_device *spi,
2150                     spi_res_release_t release,
2151                     size_t size, gfp_t gfp)
2152 {
2153         struct spi_res *sres;
2154
2155         sres = kzalloc(sizeof(*sres) + size, gfp);
2156         if (!sres)
2157                 return NULL;
2158
2159         INIT_LIST_HEAD(&sres->entry);
2160         sres->release = release;
2161
2162         return sres->data;
2163 }
2164 EXPORT_SYMBOL_GPL(spi_res_alloc);
2165
2166 /**
2167  * spi_res_free - free an spi resource
2168  * @res: pointer to the custom data of a resource
2169  *
2170  */
2171 void spi_res_free(void *res)
2172 {
2173         struct spi_res *sres = container_of(res, struct spi_res, data);
2174
2175         if (!res)
2176                 return;
2177
2178         WARN_ON(!list_empty(&sres->entry));
2179         kfree(sres);
2180 }
2181 EXPORT_SYMBOL_GPL(spi_res_free);
2182
2183 /**
2184  * spi_res_add - add a spi_res to the spi_message
2185  * @message: the spi message
2186  * @res:     the spi_resource
2187  */
2188 void spi_res_add(struct spi_message *message, void *res)
2189 {
2190         struct spi_res *sres = container_of(res, struct spi_res, data);
2191
2192         WARN_ON(!list_empty(&sres->entry));
2193         list_add_tail(&sres->entry, &message->resources);
2194 }
2195 EXPORT_SYMBOL_GPL(spi_res_add);
2196
2197 /**
2198  * spi_res_release - release all spi resources for this message
2199  * @master:  the @spi_master
2200  * @message: the @spi_message
2201  */
2202 void spi_res_release(struct spi_master *master,
2203                      struct spi_message *message)
2204 {
2205         struct spi_res *res;
2206
2207         while (!list_empty(&message->resources)) {
2208                 res = list_last_entry(&message->resources,
2209                                       struct spi_res, entry);
2210
2211                 if (res->release)
2212                         res->release(master, message, res->data);
2213
2214                 list_del(&res->entry);
2215
2216                 kfree(res);
2217         }
2218 }
2219 EXPORT_SYMBOL_GPL(spi_res_release);
2220
2221 /*-------------------------------------------------------------------------*/
2222
2223 /* Core methods for spi_message alterations */
2224
2225 static void __spi_replace_transfers_release(struct spi_master *master,
2226                                             struct spi_message *msg,
2227                                             void *res)
2228 {
2229         struct spi_replaced_transfers *rxfer = res;
2230         size_t i;
2231
2232         /* call extra callback if requested */
2233         if (rxfer->release)
2234                 rxfer->release(master, msg, res);
2235
2236         /* insert replaced transfers back into the message */
2237         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2238
2239         /* remove the formerly inserted entries */
2240         for (i = 0; i < rxfer->inserted; i++)
2241                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2242 }
2243
2244 /**
2245  * spi_replace_transfers - replace transfers with several transfers
2246  *                         and register change with spi_message.resources
2247  * @msg:           the spi_message we work upon
2248  * @xfer_first:    the first spi_transfer we want to replace
2249  * @remove:        number of transfers to remove
2250  * @insert:        the number of transfers we want to insert instead
2251  * @release:       extra release code necessary in some circumstances
2252  * @extradatasize: extra data to allocate (with alignment guarantees
2253  *                 of struct @spi_transfer)
2254  * @gfp:           gfp flags
2255  *
2256  * Returns: pointer to @spi_replaced_transfers,
2257  *          PTR_ERR(...) in case of errors.
2258  */
2259 struct spi_replaced_transfers *spi_replace_transfers(
2260         struct spi_message *msg,
2261         struct spi_transfer *xfer_first,
2262         size_t remove,
2263         size_t insert,
2264         spi_replaced_release_t release,
2265         size_t extradatasize,
2266         gfp_t gfp)
2267 {
2268         struct spi_replaced_transfers *rxfer;
2269         struct spi_transfer *xfer;
2270         size_t i;
2271
2272         /* allocate the structure using spi_res */
2273         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2274                               insert * sizeof(struct spi_transfer)
2275                               + sizeof(struct spi_replaced_transfers)
2276                               + extradatasize,
2277                               gfp);
2278         if (!rxfer)
2279                 return ERR_PTR(-ENOMEM);
2280
2281         /* the release code to invoke before running the generic release */
2282         rxfer->release = release;
2283
2284         /* assign extradata */
2285         if (extradatasize)
2286                 rxfer->extradata =
2287                         &rxfer->inserted_transfers[insert];
2288
2289         /* init the replaced_transfers list */
2290         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2291
2292         /* assign the list_entry after which we should reinsert
2293          * the @replaced_transfers - it may be spi_message.messages!
2294          */
2295         rxfer->replaced_after = xfer_first->transfer_list.prev;
2296
2297         /* remove the requested number of transfers */
2298         for (i = 0; i < remove; i++) {
2299                 /* if the entry after replaced_after it is msg->transfers
2300                  * then we have been requested to remove more transfers
2301                  * than are in the list
2302                  */
2303                 if (rxfer->replaced_after->next == &msg->transfers) {
2304                         dev_err(&msg->spi->dev,
2305                                 "requested to remove more spi_transfers than are available\n");
2306                         /* insert replaced transfers back into the message */
2307                         list_splice(&rxfer->replaced_transfers,
2308                                     rxfer->replaced_after);
2309
2310                         /* free the spi_replace_transfer structure */
2311                         spi_res_free(rxfer);
2312
2313                         /* and return with an error */
2314                         return ERR_PTR(-EINVAL);
2315                 }
2316
2317                 /* remove the entry after replaced_after from list of
2318                  * transfers and add it to list of replaced_transfers
2319                  */
2320                 list_move_tail(rxfer->replaced_after->next,
2321                                &rxfer->replaced_transfers);
2322         }
2323
2324         /* create copy of the given xfer with identical settings
2325          * based on the first transfer to get removed
2326          */
2327         for (i = 0; i < insert; i++) {
2328                 /* we need to run in reverse order */
2329                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2330
2331                 /* copy all spi_transfer data */
2332                 memcpy(xfer, xfer_first, sizeof(*xfer));
2333
2334                 /* add to list */
2335                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2336
2337                 /* clear cs_change and delay_usecs for all but the last */
2338                 if (i) {
2339                         xfer->cs_change = false;
2340                         xfer->delay_usecs = 0;
2341                 }
2342         }
2343
2344         /* set up inserted */
2345         rxfer->inserted = insert;
2346
2347         /* and register it with spi_res/spi_message */
2348         spi_res_add(msg, rxfer);
2349
2350         return rxfer;
2351 }
2352 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2353
2354 static int __spi_split_transfer_maxsize(struct spi_master *master,
2355                                         struct spi_message *msg,
2356                                         struct spi_transfer **xferp,
2357                                         size_t maxsize,
2358                                         gfp_t gfp)
2359 {
2360         struct spi_transfer *xfer = *xferp, *xfers;
2361         struct spi_replaced_transfers *srt;
2362         size_t offset;
2363         size_t count, i;
2364
2365         /* warn once about this fact that we are splitting a transfer */
2366         dev_warn_once(&msg->spi->dev,
2367                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2368                       xfer->len, maxsize);
2369
2370         /* calculate how many we have to replace */
2371         count = DIV_ROUND_UP(xfer->len, maxsize);
2372
2373         /* create replacement */
2374         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2375         if (IS_ERR(srt))
2376                 return PTR_ERR(srt);
2377         xfers = srt->inserted_transfers;
2378
2379         /* now handle each of those newly inserted spi_transfers
2380          * note that the replacements spi_transfers all are preset
2381          * to the same values as *xferp, so tx_buf, rx_buf and len
2382          * are all identical (as well as most others)
2383          * so we just have to fix up len and the pointers.
2384          *
2385          * this also includes support for the depreciated
2386          * spi_message.is_dma_mapped interface
2387          */
2388
2389         /* the first transfer just needs the length modified, so we
2390          * run it outside the loop
2391          */
2392         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2393
2394         /* all the others need rx_buf/tx_buf also set */
2395         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2396                 /* update rx_buf, tx_buf and dma */
2397                 if (xfers[i].rx_buf)
2398                         xfers[i].rx_buf += offset;
2399                 if (xfers[i].rx_dma)
2400                         xfers[i].rx_dma += offset;
2401                 if (xfers[i].tx_buf)
2402                         xfers[i].tx_buf += offset;
2403                 if (xfers[i].tx_dma)
2404                         xfers[i].tx_dma += offset;
2405
2406                 /* update length */
2407                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2408         }
2409
2410         /* we set up xferp to the last entry we have inserted,
2411          * so that we skip those already split transfers
2412          */
2413         *xferp = &xfers[count - 1];
2414
2415         /* increment statistics counters */
2416         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2417                                        transfers_split_maxsize);
2418         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2419                                        transfers_split_maxsize);
2420
2421         return 0;
2422 }
2423
2424 /**
2425  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2426  *                              when an individual transfer exceeds a
2427  *                              certain size
2428  * @master:    the @spi_master for this transfer
2429  * @msg:   the @spi_message to transform
2430  * @maxsize:  the maximum when to apply this
2431  * @gfp: GFP allocation flags
2432  *
2433  * Return: status of transformation
2434  */
2435 int spi_split_transfers_maxsize(struct spi_master *master,
2436                                 struct spi_message *msg,
2437                                 size_t maxsize,
2438                                 gfp_t gfp)
2439 {
2440         struct spi_transfer *xfer;
2441         int ret;
2442
2443         /* iterate over the transfer_list,
2444          * but note that xfer is advanced to the last transfer inserted
2445          * to avoid checking sizes again unnecessarily (also xfer does
2446          * potentiall belong to a different list by the time the
2447          * replacement has happened
2448          */
2449         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2450                 if (xfer->len > maxsize) {
2451                         ret = __spi_split_transfer_maxsize(
2452                                 master, msg, &xfer, maxsize, gfp);
2453                         if (ret)
2454                                 return ret;
2455                 }
2456         }
2457
2458         return 0;
2459 }
2460 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2461
2462 /*-------------------------------------------------------------------------*/
2463
2464 /* Core methods for SPI master protocol drivers.  Some of the
2465  * other core methods are currently defined as inline functions.
2466  */
2467
2468 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2469 {
2470         if (master->bits_per_word_mask) {
2471                 /* Only 32 bits fit in the mask */
2472                 if (bits_per_word > 32)
2473                         return -EINVAL;
2474                 if (!(master->bits_per_word_mask &
2475                                 SPI_BPW_MASK(bits_per_word)))
2476                         return -EINVAL;
2477         }
2478
2479         return 0;
2480 }
2481
2482 /**
2483  * spi_setup - setup SPI mode and clock rate
2484  * @spi: the device whose settings are being modified
2485  * Context: can sleep, and no requests are queued to the device
2486  *
2487  * SPI protocol drivers may need to update the transfer mode if the
2488  * device doesn't work with its default.  They may likewise need
2489  * to update clock rates or word sizes from initial values.  This function
2490  * changes those settings, and must be called from a context that can sleep.
2491  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2492  * effect the next time the device is selected and data is transferred to
2493  * or from it.  When this function returns, the spi device is deselected.
2494  *
2495  * Note that this call will fail if the protocol driver specifies an option
2496  * that the underlying controller or its driver does not support.  For
2497  * example, not all hardware supports wire transfers using nine bit words,
2498  * LSB-first wire encoding, or active-high chipselects.
2499  *
2500  * Return: zero on success, else a negative error code.
2501  */
2502 int spi_setup(struct spi_device *spi)
2503 {
2504         unsigned        bad_bits, ugly_bits;
2505         int             status;
2506
2507         /* check mode to prevent that DUAL and QUAD set at the same time
2508          */
2509         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2510                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2511                 dev_err(&spi->dev,
2512                 "setup: can not select dual and quad at the same time\n");
2513                 return -EINVAL;
2514         }
2515         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2516          */
2517         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2518                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2519                 return -EINVAL;
2520         /* help drivers fail *cleanly* when they need options
2521          * that aren't supported with their current master
2522          */
2523         bad_bits = spi->mode & ~spi->master->mode_bits;
2524         ugly_bits = bad_bits &
2525                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2526         if (ugly_bits) {
2527                 dev_warn(&spi->dev,
2528                          "setup: ignoring unsupported mode bits %x\n",
2529                          ugly_bits);
2530                 spi->mode &= ~ugly_bits;
2531                 bad_bits &= ~ugly_bits;
2532         }
2533         if (bad_bits) {
2534                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2535                         bad_bits);
2536                 return -EINVAL;
2537         }
2538
2539         if (!spi->bits_per_word)
2540                 spi->bits_per_word = 8;
2541
2542         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2543         if (status)
2544                 return status;
2545
2546         if (!spi->max_speed_hz)
2547                 spi->max_speed_hz = spi->master->max_speed_hz;
2548
2549         if (spi->master->setup)
2550                 status = spi->master->setup(spi);
2551
2552         spi_set_cs(spi, false);
2553
2554         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2555                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2556                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2557                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2558                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2559                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2560                         spi->bits_per_word, spi->max_speed_hz,
2561                         status);
2562
2563         return status;
2564 }
2565 EXPORT_SYMBOL_GPL(spi_setup);
2566
2567 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2568 {
2569         struct spi_master *master = spi->master;
2570         struct spi_transfer *xfer;
2571         int w_size;
2572
2573         if (list_empty(&message->transfers))
2574                 return -EINVAL;
2575
2576         /* Half-duplex links include original MicroWire, and ones with
2577          * only one data pin like SPI_3WIRE (switches direction) or where
2578          * either MOSI or MISO is missing.  They can also be caused by
2579          * software limitations.
2580          */
2581         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2582                         || (spi->mode & SPI_3WIRE)) {
2583                 unsigned flags = master->flags;
2584
2585                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2586                         if (xfer->rx_buf && xfer->tx_buf)
2587                                 return -EINVAL;
2588                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2589                                 return -EINVAL;
2590                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2591                                 return -EINVAL;
2592                 }
2593         }
2594
2595         /**
2596          * Set transfer bits_per_word and max speed as spi device default if
2597          * it is not set for this transfer.
2598          * Set transfer tx_nbits and rx_nbits as single transfer default
2599          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2600          */
2601         message->frame_length = 0;
2602         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2603                 message->frame_length += xfer->len;
2604                 if (!xfer->bits_per_word)
2605                         xfer->bits_per_word = spi->bits_per_word;
2606
2607                 if (!xfer->speed_hz)
2608                         xfer->speed_hz = spi->max_speed_hz;
2609                 if (!xfer->speed_hz)
2610                         xfer->speed_hz = master->max_speed_hz;
2611
2612                 if (master->max_speed_hz &&
2613                     xfer->speed_hz > master->max_speed_hz)
2614                         xfer->speed_hz = master->max_speed_hz;
2615
2616                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2617                         return -EINVAL;
2618
2619                 /*
2620                  * SPI transfer length should be multiple of SPI word size
2621                  * where SPI word size should be power-of-two multiple
2622                  */
2623                 if (xfer->bits_per_word <= 8)
2624                         w_size = 1;
2625                 else if (xfer->bits_per_word <= 16)
2626                         w_size = 2;
2627                 else
2628                         w_size = 4;
2629
2630                 /* No partial transfers accepted */
2631                 if (xfer->len % w_size)
2632                         return -EINVAL;
2633
2634                 if (xfer->speed_hz && master->min_speed_hz &&
2635                     xfer->speed_hz < master->min_speed_hz)
2636                         return -EINVAL;
2637
2638                 if (xfer->tx_buf && !xfer->tx_nbits)
2639                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2640                 if (xfer->rx_buf && !xfer->rx_nbits)
2641                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2642                 /* check transfer tx/rx_nbits:
2643                  * 1. check the value matches one of single, dual and quad
2644                  * 2. check tx/rx_nbits match the mode in spi_device
2645                  */
2646                 if (xfer->tx_buf) {
2647                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2648                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2649                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2650                                 return -EINVAL;
2651                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2652                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2653                                 return -EINVAL;
2654                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2655                                 !(spi->mode & SPI_TX_QUAD))
2656                                 return -EINVAL;
2657                 }
2658                 /* check transfer rx_nbits */
2659                 if (xfer->rx_buf) {
2660                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2661                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2662                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2663                                 return -EINVAL;
2664                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2665                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2666                                 return -EINVAL;
2667                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2668                                 !(spi->mode & SPI_RX_QUAD))
2669                                 return -EINVAL;
2670                 }
2671         }
2672
2673         message->status = -EINPROGRESS;
2674
2675         return 0;
2676 }
2677
2678 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2679 {
2680         struct spi_master *master = spi->master;
2681
2682         message->spi = spi;
2683
2684         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2685         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2686
2687         trace_spi_message_submit(message);
2688
2689         return master->transfer(spi, message);
2690 }
2691
2692 /**
2693  * spi_async - asynchronous SPI transfer
2694  * @spi: device with which data will be exchanged
2695  * @message: describes the data transfers, including completion callback
2696  * Context: any (irqs may be blocked, etc)
2697  *
2698  * This call may be used in_irq and other contexts which can't sleep,
2699  * as well as from task contexts which can sleep.
2700  *
2701  * The completion callback is invoked in a context which can't sleep.
2702  * Before that invocation, the value of message->status is undefined.
2703  * When the callback is issued, message->status holds either zero (to
2704  * indicate complete success) or a negative error code.  After that
2705  * callback returns, the driver which issued the transfer request may
2706  * deallocate the associated memory; it's no longer in use by any SPI
2707  * core or controller driver code.
2708  *
2709  * Note that although all messages to a spi_device are handled in
2710  * FIFO order, messages may go to different devices in other orders.
2711  * Some device might be higher priority, or have various "hard" access
2712  * time requirements, for example.
2713  *
2714  * On detection of any fault during the transfer, processing of
2715  * the entire message is aborted, and the device is deselected.
2716  * Until returning from the associated message completion callback,
2717  * no other spi_message queued to that device will be processed.
2718  * (This rule applies equally to all the synchronous transfer calls,
2719  * which are wrappers around this core asynchronous primitive.)
2720  *
2721  * Return: zero on success, else a negative error code.
2722  */
2723 int spi_async(struct spi_device *spi, struct spi_message *message)
2724 {
2725         struct spi_master *master = spi->master;
2726         int ret;
2727         unsigned long flags;
2728
2729         ret = __spi_validate(spi, message);
2730         if (ret != 0)
2731                 return ret;
2732
2733         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2734
2735         if (master->bus_lock_flag)
2736                 ret = -EBUSY;
2737         else
2738                 ret = __spi_async(spi, message);
2739
2740         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2741
2742         return ret;
2743 }
2744 EXPORT_SYMBOL_GPL(spi_async);
2745
2746 /**
2747  * spi_async_locked - version of spi_async with exclusive bus usage
2748  * @spi: device with which data will be exchanged
2749  * @message: describes the data transfers, including completion callback
2750  * Context: any (irqs may be blocked, etc)
2751  *
2752  * This call may be used in_irq and other contexts which can't sleep,
2753  * as well as from task contexts which can sleep.
2754  *
2755  * The completion callback is invoked in a context which can't sleep.
2756  * Before that invocation, the value of message->status is undefined.
2757  * When the callback is issued, message->status holds either zero (to
2758  * indicate complete success) or a negative error code.  After that
2759  * callback returns, the driver which issued the transfer request may
2760  * deallocate the associated memory; it's no longer in use by any SPI
2761  * core or controller driver code.
2762  *
2763  * Note that although all messages to a spi_device are handled in
2764  * FIFO order, messages may go to different devices in other orders.
2765  * Some device might be higher priority, or have various "hard" access
2766  * time requirements, for example.
2767  *
2768  * On detection of any fault during the transfer, processing of
2769  * the entire message is aborted, and the device is deselected.
2770  * Until returning from the associated message completion callback,
2771  * no other spi_message queued to that device will be processed.
2772  * (This rule applies equally to all the synchronous transfer calls,
2773  * which are wrappers around this core asynchronous primitive.)
2774  *
2775  * Return: zero on success, else a negative error code.
2776  */
2777 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2778 {
2779         struct spi_master *master = spi->master;
2780         int ret;
2781         unsigned long flags;
2782
2783         ret = __spi_validate(spi, message);
2784         if (ret != 0)
2785                 return ret;
2786
2787         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2788
2789         ret = __spi_async(spi, message);
2790
2791         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2792
2793         return ret;
2794
2795 }
2796 EXPORT_SYMBOL_GPL(spi_async_locked);
2797
2798
2799 int spi_flash_read(struct spi_device *spi,
2800                    struct spi_flash_read_message *msg)
2801
2802 {
2803         struct spi_master *master = spi->master;
2804         struct device *rx_dev = NULL;
2805         int ret;
2806
2807         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2808              msg->addr_nbits == SPI_NBITS_DUAL) &&
2809             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2810                 return -EINVAL;
2811         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2812              msg->addr_nbits == SPI_NBITS_QUAD) &&
2813             !(spi->mode & SPI_TX_QUAD))
2814                 return -EINVAL;
2815         if (msg->data_nbits == SPI_NBITS_DUAL &&
2816             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2817                 return -EINVAL;
2818         if (msg->data_nbits == SPI_NBITS_QUAD &&
2819             !(spi->mode &  SPI_RX_QUAD))
2820                 return -EINVAL;
2821
2822         if (master->auto_runtime_pm) {
2823                 ret = pm_runtime_get_sync(master->dev.parent);
2824                 if (ret < 0) {
2825                         dev_err(&master->dev, "Failed to power device: %d\n",
2826                                 ret);
2827                         return ret;
2828                 }
2829         }
2830
2831         mutex_lock(&master->bus_lock_mutex);
2832         mutex_lock(&master->io_mutex);
2833         if (master->dma_rx) {
2834                 rx_dev = master->dma_rx->device->dev;
2835                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2836                                   msg->buf, msg->len,
2837                                   DMA_FROM_DEVICE);
2838                 if (!ret)
2839                         msg->cur_msg_mapped = true;
2840         }
2841         ret = master->spi_flash_read(spi, msg);
2842         if (msg->cur_msg_mapped)
2843                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2844                               DMA_FROM_DEVICE);
2845         mutex_unlock(&master->io_mutex);
2846         mutex_unlock(&master->bus_lock_mutex);
2847
2848         if (master->auto_runtime_pm)
2849                 pm_runtime_put(master->dev.parent);
2850
2851         return ret;
2852 }
2853 EXPORT_SYMBOL_GPL(spi_flash_read);
2854
2855 /*-------------------------------------------------------------------------*/
2856
2857 /* Utility methods for SPI master protocol drivers, layered on
2858  * top of the core.  Some other utility methods are defined as
2859  * inline functions.
2860  */
2861
2862 static void spi_complete(void *arg)
2863 {
2864         complete(arg);
2865 }
2866
2867 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2868 {
2869         DECLARE_COMPLETION_ONSTACK(done);
2870         int status;
2871         struct spi_master *master = spi->master;
2872         unsigned long flags;
2873
2874         status = __spi_validate(spi, message);
2875         if (status != 0)
2876                 return status;
2877
2878         message->complete = spi_complete;
2879         message->context = &done;
2880         message->spi = spi;
2881
2882         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2883         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2884
2885         /* If we're not using the legacy transfer method then we will
2886          * try to transfer in the calling context so special case.
2887          * This code would be less tricky if we could remove the
2888          * support for driver implemented message queues.
2889          */
2890         if (master->transfer == spi_queued_transfer) {
2891                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2892
2893                 trace_spi_message_submit(message);
2894
2895                 status = __spi_queued_transfer(spi, message, false);
2896
2897                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2898         } else {
2899                 status = spi_async_locked(spi, message);
2900         }
2901
2902         if (status == 0) {
2903                 /* Push out the messages in the calling context if we
2904                  * can.
2905                  */
2906                 if (master->transfer == spi_queued_transfer) {
2907                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2908                                                        spi_sync_immediate);
2909                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2910                                                        spi_sync_immediate);
2911                         __spi_pump_messages(master, false);
2912                 }
2913
2914                 wait_for_completion(&done);
2915                 status = message->status;
2916         }
2917         message->context = NULL;
2918         return status;
2919 }
2920
2921 /**
2922  * spi_sync - blocking/synchronous SPI data transfers
2923  * @spi: device with which data will be exchanged
2924  * @message: describes the data transfers
2925  * Context: can sleep
2926  *
2927  * This call may only be used from a context that may sleep.  The sleep
2928  * is non-interruptible, and has no timeout.  Low-overhead controller
2929  * drivers may DMA directly into and out of the message buffers.
2930  *
2931  * Note that the SPI device's chip select is active during the message,
2932  * and then is normally disabled between messages.  Drivers for some
2933  * frequently-used devices may want to minimize costs of selecting a chip,
2934  * by leaving it selected in anticipation that the next message will go
2935  * to the same chip.  (That may increase power usage.)
2936  *
2937  * Also, the caller is guaranteeing that the memory associated with the
2938  * message will not be freed before this call returns.
2939  *
2940  * Return: zero on success, else a negative error code.
2941  */
2942 int spi_sync(struct spi_device *spi, struct spi_message *message)
2943 {
2944         int ret;
2945
2946         mutex_lock(&spi->master->bus_lock_mutex);
2947         ret = __spi_sync(spi, message);
2948         mutex_unlock(&spi->master->bus_lock_mutex);
2949
2950         return ret;
2951 }
2952 EXPORT_SYMBOL_GPL(spi_sync);
2953
2954 /**
2955  * spi_sync_locked - version of spi_sync with exclusive bus usage
2956  * @spi: device with which data will be exchanged
2957  * @message: describes the data transfers
2958  * Context: can sleep
2959  *
2960  * This call may only be used from a context that may sleep.  The sleep
2961  * is non-interruptible, and has no timeout.  Low-overhead controller
2962  * drivers may DMA directly into and out of the message buffers.
2963  *
2964  * This call should be used by drivers that require exclusive access to the
2965  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2966  * be released by a spi_bus_unlock call when the exclusive access is over.
2967  *
2968  * Return: zero on success, else a negative error code.
2969  */
2970 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2971 {
2972         return __spi_sync(spi, message);
2973 }
2974 EXPORT_SYMBOL_GPL(spi_sync_locked);
2975
2976 /**
2977  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2978  * @master: SPI bus master that should be locked for exclusive bus access
2979  * Context: can sleep
2980  *
2981  * This call may only be used from a context that may sleep.  The sleep
2982  * is non-interruptible, and has no timeout.
2983  *
2984  * This call should be used by drivers that require exclusive access to the
2985  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2986  * exclusive access is over. Data transfer must be done by spi_sync_locked
2987  * and spi_async_locked calls when the SPI bus lock is held.
2988  *
2989  * Return: always zero.
2990  */
2991 int spi_bus_lock(struct spi_master *master)
2992 {
2993         unsigned long flags;
2994
2995         mutex_lock(&master->bus_lock_mutex);
2996
2997         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2998         master->bus_lock_flag = 1;
2999         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
3000
3001         /* mutex remains locked until spi_bus_unlock is called */
3002
3003         return 0;
3004 }
3005 EXPORT_SYMBOL_GPL(spi_bus_lock);
3006
3007 /**
3008  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3009  * @master: SPI bus master that was locked for exclusive bus access
3010  * Context: can sleep
3011  *
3012  * This call may only be used from a context that may sleep.  The sleep
3013  * is non-interruptible, and has no timeout.
3014  *
3015  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3016  * call.
3017  *
3018  * Return: always zero.
3019  */
3020 int spi_bus_unlock(struct spi_master *master)
3021 {
3022         master->bus_lock_flag = 0;
3023
3024         mutex_unlock(&master->bus_lock_mutex);
3025
3026         return 0;
3027 }
3028 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3029
3030 /* portable code must never pass more than 32 bytes */
3031 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3032
3033 static u8       *buf;
3034
3035 /**
3036  * spi_write_then_read - SPI synchronous write followed by read
3037  * @spi: device with which data will be exchanged
3038  * @txbuf: data to be written (need not be dma-safe)
3039  * @n_tx: size of txbuf, in bytes
3040  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3041  * @n_rx: size of rxbuf, in bytes
3042  * Context: can sleep
3043  *
3044  * This performs a half duplex MicroWire style transaction with the
3045  * device, sending txbuf and then reading rxbuf.  The return value
3046  * is zero for success, else a negative errno status code.
3047  * This call may only be used from a context that may sleep.
3048  *
3049  * Parameters to this routine are always copied using a small buffer;
3050  * portable code should never use this for more than 32 bytes.
3051  * Performance-sensitive or bulk transfer code should instead use
3052  * spi_{async,sync}() calls with dma-safe buffers.
3053  *
3054  * Return: zero on success, else a negative error code.
3055  */
3056 int spi_write_then_read(struct spi_device *spi,
3057                 const void *txbuf, unsigned n_tx,
3058                 void *rxbuf, unsigned n_rx)
3059 {
3060         static DEFINE_MUTEX(lock);
3061
3062         int                     status;
3063         struct spi_message      message;
3064         struct spi_transfer     x[2];
3065         u8                      *local_buf;
3066
3067         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3068          * copying here, (as a pure convenience thing), but we can
3069          * keep heap costs out of the hot path unless someone else is
3070          * using the pre-allocated buffer or the transfer is too large.
3071          */
3072         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3073                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3074                                     GFP_KERNEL | GFP_DMA);
3075                 if (!local_buf)
3076                         return -ENOMEM;
3077         } else {
3078                 local_buf = buf;
3079         }
3080
3081         spi_message_init(&message);
3082         memset(x, 0, sizeof(x));
3083         if (n_tx) {
3084                 x[0].len = n_tx;
3085                 spi_message_add_tail(&x[0], &message);
3086         }
3087         if (n_rx) {
3088                 x[1].len = n_rx;
3089                 spi_message_add_tail(&x[1], &message);
3090         }
3091
3092         memcpy(local_buf, txbuf, n_tx);
3093         x[0].tx_buf = local_buf;
3094         x[1].rx_buf = local_buf + n_tx;
3095
3096         /* do the i/o */
3097         status = spi_sync(spi, &message);
3098         if (status == 0)
3099                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3100
3101         if (x[0].tx_buf == buf)
3102                 mutex_unlock(&lock);
3103         else
3104                 kfree(local_buf);
3105
3106         return status;
3107 }
3108 EXPORT_SYMBOL_GPL(spi_write_then_read);
3109
3110 /*-------------------------------------------------------------------------*/
3111
3112 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3113 static int __spi_of_device_match(struct device *dev, void *data)
3114 {
3115         return dev->of_node == data;
3116 }
3117
3118 /* must call put_device() when done with returned spi_device device */
3119 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3120 {
3121         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3122                                                 __spi_of_device_match);
3123         return dev ? to_spi_device(dev) : NULL;
3124 }
3125
3126 static int __spi_of_master_match(struct device *dev, const void *data)
3127 {
3128         return dev->of_node == data;
3129 }
3130
3131 /* the spi masters are not using spi_bus, so we find it with another way */
3132 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3133 {
3134         struct device *dev;
3135
3136         dev = class_find_device(&spi_master_class, NULL, node,
3137                                 __spi_of_master_match);
3138         if (!dev)
3139                 return NULL;
3140
3141         /* reference got in class_find_device */
3142         return container_of(dev, struct spi_master, dev);
3143 }
3144
3145 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3146                          void *arg)
3147 {
3148         struct of_reconfig_data *rd = arg;
3149         struct spi_master *master;
3150         struct spi_device *spi;
3151
3152         switch (of_reconfig_get_state_change(action, arg)) {
3153         case OF_RECONFIG_CHANGE_ADD:
3154                 master = of_find_spi_master_by_node(rd->dn->parent);
3155                 if (master == NULL)
3156                         return NOTIFY_OK;       /* not for us */
3157
3158                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3159                         put_device(&master->dev);
3160                         return NOTIFY_OK;
3161                 }
3162
3163                 spi = of_register_spi_device(master, rd->dn);
3164                 put_device(&master->dev);
3165
3166                 if (IS_ERR(spi)) {
3167                         pr_err("%s: failed to create for '%s'\n",
3168                                         __func__, rd->dn->full_name);
3169                         of_node_clear_flag(rd->dn, OF_POPULATED);
3170                         return notifier_from_errno(PTR_ERR(spi));
3171                 }
3172                 break;
3173
3174         case OF_RECONFIG_CHANGE_REMOVE:
3175                 /* already depopulated? */
3176                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3177                         return NOTIFY_OK;
3178
3179                 /* find our device by node */
3180                 spi = of_find_spi_device_by_node(rd->dn);
3181                 if (spi == NULL)
3182                         return NOTIFY_OK;       /* no? not meant for us */
3183
3184                 /* unregister takes one ref away */
3185                 spi_unregister_device(spi);
3186
3187                 /* and put the reference of the find */
3188                 put_device(&spi->dev);
3189                 break;
3190         }
3191
3192         return NOTIFY_OK;
3193 }
3194
3195 static struct notifier_block spi_of_notifier = {
3196         .notifier_call = of_spi_notify,
3197 };
3198 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3199 extern struct notifier_block spi_of_notifier;
3200 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3201
3202 #if IS_ENABLED(CONFIG_ACPI)
3203 static int spi_acpi_master_match(struct device *dev, const void *data)
3204 {
3205         return ACPI_COMPANION(dev->parent) == data;
3206 }
3207
3208 static int spi_acpi_device_match(struct device *dev, void *data)
3209 {
3210         return ACPI_COMPANION(dev) == data;
3211 }
3212
3213 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3214 {
3215         struct device *dev;
3216
3217         dev = class_find_device(&spi_master_class, NULL, adev,
3218                                 spi_acpi_master_match);
3219         if (!dev)
3220                 return NULL;
3221
3222         return container_of(dev, struct spi_master, dev);
3223 }
3224
3225 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3226 {
3227         struct device *dev;
3228
3229         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3230
3231         return dev ? to_spi_device(dev) : NULL;
3232 }
3233
3234 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3235                            void *arg)
3236 {
3237         struct acpi_device *adev = arg;
3238         struct spi_master *master;
3239         struct spi_device *spi;
3240
3241         switch (value) {
3242         case ACPI_RECONFIG_DEVICE_ADD:
3243                 master = acpi_spi_find_master_by_adev(adev->parent);
3244                 if (!master)
3245                         break;
3246
3247                 acpi_register_spi_device(master, adev);
3248                 put_device(&master->dev);
3249                 break;
3250         case ACPI_RECONFIG_DEVICE_REMOVE:
3251                 if (!acpi_device_enumerated(adev))
3252                         break;
3253
3254                 spi = acpi_spi_find_device_by_adev(adev);
3255                 if (!spi)
3256                         break;
3257
3258                 spi_unregister_device(spi);
3259                 put_device(&spi->dev);
3260                 break;
3261         }
3262
3263         return NOTIFY_OK;
3264 }
3265
3266 static struct notifier_block spi_acpi_notifier = {
3267         .notifier_call = acpi_spi_notify,
3268 };
3269 #else
3270 extern struct notifier_block spi_acpi_notifier;
3271 #endif
3272
3273 static int __init spi_init(void)
3274 {
3275         int     status;
3276
3277         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3278         if (!buf) {
3279                 status = -ENOMEM;
3280                 goto err0;
3281         }
3282
3283         status = bus_register(&spi_bus_type);
3284         if (status < 0)
3285                 goto err1;
3286
3287         status = class_register(&spi_master_class);
3288         if (status < 0)
3289                 goto err2;
3290
3291         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3292                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3293         if (IS_ENABLED(CONFIG_ACPI))
3294                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3295
3296         return 0;
3297
3298 err2:
3299         bus_unregister(&spi_bus_type);
3300 err1:
3301         kfree(buf);
3302         buf = NULL;
3303 err0:
3304         return status;
3305 }
3306
3307 /* board_info is normally registered in arch_initcall(),
3308  * but even essential drivers wait till later
3309  *
3310  * REVISIT only boardinfo really needs static linking. the rest (device and
3311  * driver registration) _could_ be dynamically linked (modular) ... costs
3312  * include needing to have boardinfo data structures be much more public.
3313  */
3314 postcore_initcall(spi_init);
3315