Merge tag 'spi-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
[sfrench/cifs-2.6.git] / drivers / spi / spi.c
1 /*
2  * SPI init/core code
3  *
4  * Copyright (C) 2005 David Brownell
5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
40
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
43
44 static void spidev_release(struct device *dev)
45 {
46         struct spi_device       *spi = to_spi_device(dev);
47
48         /* spi masters may cleanup for released devices */
49         if (spi->master->cleanup)
50                 spi->master->cleanup(spi);
51
52         spi_master_put(spi->master);
53         kfree(spi);
54 }
55
56 static ssize_t
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
58 {
59         const struct spi_device *spi = to_spi_device(dev);
60         int len;
61
62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
63         if (len != -ENODEV)
64                 return len;
65
66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
67 }
68 static DEVICE_ATTR_RO(modalias);
69
70 #define SPI_STATISTICS_ATTRS(field, file)                               \
71 static ssize_t spi_master_##field##_show(struct device *dev,            \
72                                          struct device_attribute *attr, \
73                                          char *buf)                     \
74 {                                                                       \
75         struct spi_master *master = container_of(dev,                   \
76                                                  struct spi_master, dev); \
77         return spi_statistics_##field##_show(&master->statistics, buf); \
78 }                                                                       \
79 static struct device_attribute dev_attr_spi_master_##field = {          \
80         .attr = { .name = file, .mode = S_IRUGO },                      \
81         .show = spi_master_##field##_show,                              \
82 };                                                                      \
83 static ssize_t spi_device_##field##_show(struct device *dev,            \
84                                          struct device_attribute *attr, \
85                                         char *buf)                      \
86 {                                                                       \
87         struct spi_device *spi = to_spi_device(dev);                    \
88         return spi_statistics_##field##_show(&spi->statistics, buf);    \
89 }                                                                       \
90 static struct device_attribute dev_attr_spi_device_##field = {          \
91         .attr = { .name = file, .mode = S_IRUGO },                      \
92         .show = spi_device_##field##_show,                              \
93 }
94
95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
97                                             char *buf)                  \
98 {                                                                       \
99         unsigned long flags;                                            \
100         ssize_t len;                                                    \
101         spin_lock_irqsave(&stat->lock, flags);                          \
102         len = sprintf(buf, format_string, stat->field);                 \
103         spin_unlock_irqrestore(&stat->lock, flags);                     \
104         return len;                                                     \
105 }                                                                       \
106 SPI_STATISTICS_ATTRS(name, file)
107
108 #define SPI_STATISTICS_SHOW(field, format_string)                       \
109         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
110                                  field, format_string)
111
112 SPI_STATISTICS_SHOW(messages, "%lu");
113 SPI_STATISTICS_SHOW(transfers, "%lu");
114 SPI_STATISTICS_SHOW(errors, "%lu");
115 SPI_STATISTICS_SHOW(timedout, "%lu");
116
117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
119 SPI_STATISTICS_SHOW(spi_async, "%lu");
120
121 SPI_STATISTICS_SHOW(bytes, "%llu");
122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
124
125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
126         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
127                                  "transfer_bytes_histo_" number,        \
128                                  transfer_bytes_histo[index],  "%lu")
129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
146
147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
148
149 static struct attribute *spi_dev_attrs[] = {
150         &dev_attr_modalias.attr,
151         NULL,
152 };
153
154 static const struct attribute_group spi_dev_group = {
155         .attrs  = spi_dev_attrs,
156 };
157
158 static struct attribute *spi_device_statistics_attrs[] = {
159         &dev_attr_spi_device_messages.attr,
160         &dev_attr_spi_device_transfers.attr,
161         &dev_attr_spi_device_errors.attr,
162         &dev_attr_spi_device_timedout.attr,
163         &dev_attr_spi_device_spi_sync.attr,
164         &dev_attr_spi_device_spi_sync_immediate.attr,
165         &dev_attr_spi_device_spi_async.attr,
166         &dev_attr_spi_device_bytes.attr,
167         &dev_attr_spi_device_bytes_rx.attr,
168         &dev_attr_spi_device_bytes_tx.attr,
169         &dev_attr_spi_device_transfer_bytes_histo0.attr,
170         &dev_attr_spi_device_transfer_bytes_histo1.attr,
171         &dev_attr_spi_device_transfer_bytes_histo2.attr,
172         &dev_attr_spi_device_transfer_bytes_histo3.attr,
173         &dev_attr_spi_device_transfer_bytes_histo4.attr,
174         &dev_attr_spi_device_transfer_bytes_histo5.attr,
175         &dev_attr_spi_device_transfer_bytes_histo6.attr,
176         &dev_attr_spi_device_transfer_bytes_histo7.attr,
177         &dev_attr_spi_device_transfer_bytes_histo8.attr,
178         &dev_attr_spi_device_transfer_bytes_histo9.attr,
179         &dev_attr_spi_device_transfer_bytes_histo10.attr,
180         &dev_attr_spi_device_transfer_bytes_histo11.attr,
181         &dev_attr_spi_device_transfer_bytes_histo12.attr,
182         &dev_attr_spi_device_transfer_bytes_histo13.attr,
183         &dev_attr_spi_device_transfer_bytes_histo14.attr,
184         &dev_attr_spi_device_transfer_bytes_histo15.attr,
185         &dev_attr_spi_device_transfer_bytes_histo16.attr,
186         &dev_attr_spi_device_transfers_split_maxsize.attr,
187         NULL,
188 };
189
190 static const struct attribute_group spi_device_statistics_group = {
191         .name  = "statistics",
192         .attrs  = spi_device_statistics_attrs,
193 };
194
195 static const struct attribute_group *spi_dev_groups[] = {
196         &spi_dev_group,
197         &spi_device_statistics_group,
198         NULL,
199 };
200
201 static struct attribute *spi_master_statistics_attrs[] = {
202         &dev_attr_spi_master_messages.attr,
203         &dev_attr_spi_master_transfers.attr,
204         &dev_attr_spi_master_errors.attr,
205         &dev_attr_spi_master_timedout.attr,
206         &dev_attr_spi_master_spi_sync.attr,
207         &dev_attr_spi_master_spi_sync_immediate.attr,
208         &dev_attr_spi_master_spi_async.attr,
209         &dev_attr_spi_master_bytes.attr,
210         &dev_attr_spi_master_bytes_rx.attr,
211         &dev_attr_spi_master_bytes_tx.attr,
212         &dev_attr_spi_master_transfer_bytes_histo0.attr,
213         &dev_attr_spi_master_transfer_bytes_histo1.attr,
214         &dev_attr_spi_master_transfer_bytes_histo2.attr,
215         &dev_attr_spi_master_transfer_bytes_histo3.attr,
216         &dev_attr_spi_master_transfer_bytes_histo4.attr,
217         &dev_attr_spi_master_transfer_bytes_histo5.attr,
218         &dev_attr_spi_master_transfer_bytes_histo6.attr,
219         &dev_attr_spi_master_transfer_bytes_histo7.attr,
220         &dev_attr_spi_master_transfer_bytes_histo8.attr,
221         &dev_attr_spi_master_transfer_bytes_histo9.attr,
222         &dev_attr_spi_master_transfer_bytes_histo10.attr,
223         &dev_attr_spi_master_transfer_bytes_histo11.attr,
224         &dev_attr_spi_master_transfer_bytes_histo12.attr,
225         &dev_attr_spi_master_transfer_bytes_histo13.attr,
226         &dev_attr_spi_master_transfer_bytes_histo14.attr,
227         &dev_attr_spi_master_transfer_bytes_histo15.attr,
228         &dev_attr_spi_master_transfer_bytes_histo16.attr,
229         &dev_attr_spi_master_transfers_split_maxsize.attr,
230         NULL,
231 };
232
233 static const struct attribute_group spi_master_statistics_group = {
234         .name  = "statistics",
235         .attrs  = spi_master_statistics_attrs,
236 };
237
238 static const struct attribute_group *spi_master_groups[] = {
239         &spi_master_statistics_group,
240         NULL,
241 };
242
243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
244                                        struct spi_transfer *xfer,
245                                        struct spi_master *master)
246 {
247         unsigned long flags;
248         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
249
250         if (l2len < 0)
251                 l2len = 0;
252
253         spin_lock_irqsave(&stats->lock, flags);
254
255         stats->transfers++;
256         stats->transfer_bytes_histo[l2len]++;
257
258         stats->bytes += xfer->len;
259         if ((xfer->tx_buf) &&
260             (xfer->tx_buf != master->dummy_tx))
261                 stats->bytes_tx += xfer->len;
262         if ((xfer->rx_buf) &&
263             (xfer->rx_buf != master->dummy_rx))
264                 stats->bytes_rx += xfer->len;
265
266         spin_unlock_irqrestore(&stats->lock, flags);
267 }
268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
269
270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
271  * and the sysfs version makes coldplug work too.
272  */
273
274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
275                                                 const struct spi_device *sdev)
276 {
277         while (id->name[0]) {
278                 if (!strcmp(sdev->modalias, id->name))
279                         return id;
280                 id++;
281         }
282         return NULL;
283 }
284
285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
286 {
287         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
288
289         return spi_match_id(sdrv->id_table, sdev);
290 }
291 EXPORT_SYMBOL_GPL(spi_get_device_id);
292
293 static int spi_match_device(struct device *dev, struct device_driver *drv)
294 {
295         const struct spi_device *spi = to_spi_device(dev);
296         const struct spi_driver *sdrv = to_spi_driver(drv);
297
298         /* Attempt an OF style match */
299         if (of_driver_match_device(dev, drv))
300                 return 1;
301
302         /* Then try ACPI */
303         if (acpi_driver_match_device(dev, drv))
304                 return 1;
305
306         if (sdrv->id_table)
307                 return !!spi_match_id(sdrv->id_table, spi);
308
309         return strcmp(spi->modalias, drv->name) == 0;
310 }
311
312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
313 {
314         const struct spi_device         *spi = to_spi_device(dev);
315         int rc;
316
317         rc = acpi_device_uevent_modalias(dev, env);
318         if (rc != -ENODEV)
319                 return rc;
320
321         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
322         return 0;
323 }
324
325 struct bus_type spi_bus_type = {
326         .name           = "spi",
327         .dev_groups     = spi_dev_groups,
328         .match          = spi_match_device,
329         .uevent         = spi_uevent,
330 };
331 EXPORT_SYMBOL_GPL(spi_bus_type);
332
333
334 static int spi_drv_probe(struct device *dev)
335 {
336         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
337         struct spi_device               *spi = to_spi_device(dev);
338         int ret;
339
340         ret = of_clk_set_defaults(dev->of_node, false);
341         if (ret)
342                 return ret;
343
344         if (dev->of_node) {
345                 spi->irq = of_irq_get(dev->of_node, 0);
346                 if (spi->irq == -EPROBE_DEFER)
347                         return -EPROBE_DEFER;
348                 if (spi->irq < 0)
349                         spi->irq = 0;
350         }
351
352         ret = dev_pm_domain_attach(dev, true);
353         if (ret != -EPROBE_DEFER) {
354                 ret = sdrv->probe(spi);
355                 if (ret)
356                         dev_pm_domain_detach(dev, true);
357         }
358
359         return ret;
360 }
361
362 static int spi_drv_remove(struct device *dev)
363 {
364         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
365         int ret;
366
367         ret = sdrv->remove(to_spi_device(dev));
368         dev_pm_domain_detach(dev, true);
369
370         return ret;
371 }
372
373 static void spi_drv_shutdown(struct device *dev)
374 {
375         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
376
377         sdrv->shutdown(to_spi_device(dev));
378 }
379
380 /**
381  * __spi_register_driver - register a SPI driver
382  * @owner: owner module of the driver to register
383  * @sdrv: the driver to register
384  * Context: can sleep
385  *
386  * Return: zero on success, else a negative error code.
387  */
388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
389 {
390         sdrv->driver.owner = owner;
391         sdrv->driver.bus = &spi_bus_type;
392         if (sdrv->probe)
393                 sdrv->driver.probe = spi_drv_probe;
394         if (sdrv->remove)
395                 sdrv->driver.remove = spi_drv_remove;
396         if (sdrv->shutdown)
397                 sdrv->driver.shutdown = spi_drv_shutdown;
398         return driver_register(&sdrv->driver);
399 }
400 EXPORT_SYMBOL_GPL(__spi_register_driver);
401
402 /*-------------------------------------------------------------------------*/
403
404 /* SPI devices should normally not be created by SPI device drivers; that
405  * would make them board-specific.  Similarly with SPI master drivers.
406  * Device registration normally goes into like arch/.../mach.../board-YYY.c
407  * with other readonly (flashable) information about mainboard devices.
408  */
409
410 struct boardinfo {
411         struct list_head        list;
412         struct spi_board_info   board_info;
413 };
414
415 static LIST_HEAD(board_list);
416 static LIST_HEAD(spi_master_list);
417
418 /*
419  * Used to protect add/del opertion for board_info list and
420  * spi_master list, and their matching process
421  */
422 static DEFINE_MUTEX(board_lock);
423
424 /**
425  * spi_alloc_device - Allocate a new SPI device
426  * @master: Controller to which device is connected
427  * Context: can sleep
428  *
429  * Allows a driver to allocate and initialize a spi_device without
430  * registering it immediately.  This allows a driver to directly
431  * fill the spi_device with device parameters before calling
432  * spi_add_device() on it.
433  *
434  * Caller is responsible to call spi_add_device() on the returned
435  * spi_device structure to add it to the SPI master.  If the caller
436  * needs to discard the spi_device without adding it, then it should
437  * call spi_dev_put() on it.
438  *
439  * Return: a pointer to the new device, or NULL.
440  */
441 struct spi_device *spi_alloc_device(struct spi_master *master)
442 {
443         struct spi_device       *spi;
444
445         if (!spi_master_get(master))
446                 return NULL;
447
448         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
449         if (!spi) {
450                 spi_master_put(master);
451                 return NULL;
452         }
453
454         spi->master = master;
455         spi->dev.parent = &master->dev;
456         spi->dev.bus = &spi_bus_type;
457         spi->dev.release = spidev_release;
458         spi->cs_gpio = -ENOENT;
459
460         spin_lock_init(&spi->statistics.lock);
461
462         device_initialize(&spi->dev);
463         return spi;
464 }
465 EXPORT_SYMBOL_GPL(spi_alloc_device);
466
467 static void spi_dev_set_name(struct spi_device *spi)
468 {
469         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
470
471         if (adev) {
472                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
473                 return;
474         }
475
476         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
477                      spi->chip_select);
478 }
479
480 static int spi_dev_check(struct device *dev, void *data)
481 {
482         struct spi_device *spi = to_spi_device(dev);
483         struct spi_device *new_spi = data;
484
485         if (spi->master == new_spi->master &&
486             spi->chip_select == new_spi->chip_select)
487                 return -EBUSY;
488         return 0;
489 }
490
491 /**
492  * spi_add_device - Add spi_device allocated with spi_alloc_device
493  * @spi: spi_device to register
494  *
495  * Companion function to spi_alloc_device.  Devices allocated with
496  * spi_alloc_device can be added onto the spi bus with this function.
497  *
498  * Return: 0 on success; negative errno on failure
499  */
500 int spi_add_device(struct spi_device *spi)
501 {
502         static DEFINE_MUTEX(spi_add_lock);
503         struct spi_master *master = spi->master;
504         struct device *dev = master->dev.parent;
505         int status;
506
507         /* Chipselects are numbered 0..max; validate. */
508         if (spi->chip_select >= master->num_chipselect) {
509                 dev_err(dev, "cs%d >= max %d\n",
510                         spi->chip_select,
511                         master->num_chipselect);
512                 return -EINVAL;
513         }
514
515         /* Set the bus ID string */
516         spi_dev_set_name(spi);
517
518         /* We need to make sure there's no other device with this
519          * chipselect **BEFORE** we call setup(), else we'll trash
520          * its configuration.  Lock against concurrent add() calls.
521          */
522         mutex_lock(&spi_add_lock);
523
524         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
525         if (status) {
526                 dev_err(dev, "chipselect %d already in use\n",
527                                 spi->chip_select);
528                 goto done;
529         }
530
531         if (master->cs_gpios)
532                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
533
534         /* Drivers may modify this initial i/o setup, but will
535          * normally rely on the device being setup.  Devices
536          * using SPI_CS_HIGH can't coexist well otherwise...
537          */
538         status = spi_setup(spi);
539         if (status < 0) {
540                 dev_err(dev, "can't setup %s, status %d\n",
541                                 dev_name(&spi->dev), status);
542                 goto done;
543         }
544
545         /* Device may be bound to an active driver when this returns */
546         status = device_add(&spi->dev);
547         if (status < 0)
548                 dev_err(dev, "can't add %s, status %d\n",
549                                 dev_name(&spi->dev), status);
550         else
551                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
552
553 done:
554         mutex_unlock(&spi_add_lock);
555         return status;
556 }
557 EXPORT_SYMBOL_GPL(spi_add_device);
558
559 /**
560  * spi_new_device - instantiate one new SPI device
561  * @master: Controller to which device is connected
562  * @chip: Describes the SPI device
563  * Context: can sleep
564  *
565  * On typical mainboards, this is purely internal; and it's not needed
566  * after board init creates the hard-wired devices.  Some development
567  * platforms may not be able to use spi_register_board_info though, and
568  * this is exported so that for example a USB or parport based adapter
569  * driver could add devices (which it would learn about out-of-band).
570  *
571  * Return: the new device, or NULL.
572  */
573 struct spi_device *spi_new_device(struct spi_master *master,
574                                   struct spi_board_info *chip)
575 {
576         struct spi_device       *proxy;
577         int                     status;
578
579         /* NOTE:  caller did any chip->bus_num checks necessary.
580          *
581          * Also, unless we change the return value convention to use
582          * error-or-pointer (not NULL-or-pointer), troubleshootability
583          * suggests syslogged diagnostics are best here (ugh).
584          */
585
586         proxy = spi_alloc_device(master);
587         if (!proxy)
588                 return NULL;
589
590         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
591
592         proxy->chip_select = chip->chip_select;
593         proxy->max_speed_hz = chip->max_speed_hz;
594         proxy->mode = chip->mode;
595         proxy->irq = chip->irq;
596         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
597         proxy->dev.platform_data = (void *) chip->platform_data;
598         proxy->controller_data = chip->controller_data;
599         proxy->controller_state = NULL;
600
601         status = spi_add_device(proxy);
602         if (status < 0) {
603                 spi_dev_put(proxy);
604                 return NULL;
605         }
606
607         return proxy;
608 }
609 EXPORT_SYMBOL_GPL(spi_new_device);
610
611 /**
612  * spi_unregister_device - unregister a single SPI device
613  * @spi: spi_device to unregister
614  *
615  * Start making the passed SPI device vanish. Normally this would be handled
616  * by spi_unregister_master().
617  */
618 void spi_unregister_device(struct spi_device *spi)
619 {
620         if (!spi)
621                 return;
622
623         if (spi->dev.of_node)
624                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
625         if (ACPI_COMPANION(&spi->dev))
626                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
627         device_unregister(&spi->dev);
628 }
629 EXPORT_SYMBOL_GPL(spi_unregister_device);
630
631 static void spi_match_master_to_boardinfo(struct spi_master *master,
632                                 struct spi_board_info *bi)
633 {
634         struct spi_device *dev;
635
636         if (master->bus_num != bi->bus_num)
637                 return;
638
639         dev = spi_new_device(master, bi);
640         if (!dev)
641                 dev_err(master->dev.parent, "can't create new device for %s\n",
642                         bi->modalias);
643 }
644
645 /**
646  * spi_register_board_info - register SPI devices for a given board
647  * @info: array of chip descriptors
648  * @n: how many descriptors are provided
649  * Context: can sleep
650  *
651  * Board-specific early init code calls this (probably during arch_initcall)
652  * with segments of the SPI device table.  Any device nodes are created later,
653  * after the relevant parent SPI controller (bus_num) is defined.  We keep
654  * this table of devices forever, so that reloading a controller driver will
655  * not make Linux forget about these hard-wired devices.
656  *
657  * Other code can also call this, e.g. a particular add-on board might provide
658  * SPI devices through its expansion connector, so code initializing that board
659  * would naturally declare its SPI devices.
660  *
661  * The board info passed can safely be __initdata ... but be careful of
662  * any embedded pointers (platform_data, etc), they're copied as-is.
663  *
664  * Return: zero on success, else a negative error code.
665  */
666 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
667 {
668         struct boardinfo *bi;
669         int i;
670
671         if (!n)
672                 return -EINVAL;
673
674         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
675         if (!bi)
676                 return -ENOMEM;
677
678         for (i = 0; i < n; i++, bi++, info++) {
679                 struct spi_master *master;
680
681                 memcpy(&bi->board_info, info, sizeof(*info));
682                 mutex_lock(&board_lock);
683                 list_add_tail(&bi->list, &board_list);
684                 list_for_each_entry(master, &spi_master_list, list)
685                         spi_match_master_to_boardinfo(master, &bi->board_info);
686                 mutex_unlock(&board_lock);
687         }
688
689         return 0;
690 }
691
692 /*-------------------------------------------------------------------------*/
693
694 static void spi_set_cs(struct spi_device *spi, bool enable)
695 {
696         if (spi->mode & SPI_CS_HIGH)
697                 enable = !enable;
698
699         if (gpio_is_valid(spi->cs_gpio))
700                 gpio_set_value(spi->cs_gpio, !enable);
701         else if (spi->master->set_cs)
702                 spi->master->set_cs(spi, !enable);
703 }
704
705 #ifdef CONFIG_HAS_DMA
706 static int spi_map_buf(struct spi_master *master, struct device *dev,
707                        struct sg_table *sgt, void *buf, size_t len,
708                        enum dma_data_direction dir)
709 {
710         const bool vmalloced_buf = is_vmalloc_addr(buf);
711         unsigned int max_seg_size = dma_get_max_seg_size(dev);
712         int desc_len;
713         int sgs;
714         struct page *vm_page;
715         void *sg_buf;
716         size_t min;
717         int i, ret;
718
719         if (vmalloced_buf) {
720                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
721                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
722         } else if (virt_addr_valid(buf)) {
723                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
724                 sgs = DIV_ROUND_UP(len, desc_len);
725         } else {
726                 return -EINVAL;
727         }
728
729         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
730         if (ret != 0)
731                 return ret;
732
733         for (i = 0; i < sgs; i++) {
734
735                 if (vmalloced_buf) {
736                         min = min_t(size_t,
737                                     len, desc_len - offset_in_page(buf));
738                         vm_page = vmalloc_to_page(buf);
739                         if (!vm_page) {
740                                 sg_free_table(sgt);
741                                 return -ENOMEM;
742                         }
743                         sg_set_page(&sgt->sgl[i], vm_page,
744                                     min, offset_in_page(buf));
745                 } else {
746                         min = min_t(size_t, len, desc_len);
747                         sg_buf = buf;
748                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
749                 }
750
751                 buf += min;
752                 len -= min;
753         }
754
755         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
756         if (!ret)
757                 ret = -ENOMEM;
758         if (ret < 0) {
759                 sg_free_table(sgt);
760                 return ret;
761         }
762
763         sgt->nents = ret;
764
765         return 0;
766 }
767
768 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
769                           struct sg_table *sgt, enum dma_data_direction dir)
770 {
771         if (sgt->orig_nents) {
772                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
773                 sg_free_table(sgt);
774         }
775 }
776
777 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
778 {
779         struct device *tx_dev, *rx_dev;
780         struct spi_transfer *xfer;
781         int ret;
782
783         if (!master->can_dma)
784                 return 0;
785
786         if (master->dma_tx)
787                 tx_dev = master->dma_tx->device->dev;
788         else
789                 tx_dev = &master->dev;
790
791         if (master->dma_rx)
792                 rx_dev = master->dma_rx->device->dev;
793         else
794                 rx_dev = &master->dev;
795
796         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
797                 if (!master->can_dma(master, msg->spi, xfer))
798                         continue;
799
800                 if (xfer->tx_buf != NULL) {
801                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
802                                           (void *)xfer->tx_buf, xfer->len,
803                                           DMA_TO_DEVICE);
804                         if (ret != 0)
805                                 return ret;
806                 }
807
808                 if (xfer->rx_buf != NULL) {
809                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
810                                           xfer->rx_buf, xfer->len,
811                                           DMA_FROM_DEVICE);
812                         if (ret != 0) {
813                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
814                                               DMA_TO_DEVICE);
815                                 return ret;
816                         }
817                 }
818         }
819
820         master->cur_msg_mapped = true;
821
822         return 0;
823 }
824
825 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
826 {
827         struct spi_transfer *xfer;
828         struct device *tx_dev, *rx_dev;
829
830         if (!master->cur_msg_mapped || !master->can_dma)
831                 return 0;
832
833         if (master->dma_tx)
834                 tx_dev = master->dma_tx->device->dev;
835         else
836                 tx_dev = &master->dev;
837
838         if (master->dma_rx)
839                 rx_dev = master->dma_rx->device->dev;
840         else
841                 rx_dev = &master->dev;
842
843         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
844                 if (!master->can_dma(master, msg->spi, xfer))
845                         continue;
846
847                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
848                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
849         }
850
851         return 0;
852 }
853 #else /* !CONFIG_HAS_DMA */
854 static inline int spi_map_buf(struct spi_master *master,
855                               struct device *dev, struct sg_table *sgt,
856                               void *buf, size_t len,
857                               enum dma_data_direction dir)
858 {
859         return -EINVAL;
860 }
861
862 static inline void spi_unmap_buf(struct spi_master *master,
863                                  struct device *dev, struct sg_table *sgt,
864                                  enum dma_data_direction dir)
865 {
866 }
867
868 static inline int __spi_map_msg(struct spi_master *master,
869                                 struct spi_message *msg)
870 {
871         return 0;
872 }
873
874 static inline int __spi_unmap_msg(struct spi_master *master,
875                                   struct spi_message *msg)
876 {
877         return 0;
878 }
879 #endif /* !CONFIG_HAS_DMA */
880
881 static inline int spi_unmap_msg(struct spi_master *master,
882                                 struct spi_message *msg)
883 {
884         struct spi_transfer *xfer;
885
886         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
887                 /*
888                  * Restore the original value of tx_buf or rx_buf if they are
889                  * NULL.
890                  */
891                 if (xfer->tx_buf == master->dummy_tx)
892                         xfer->tx_buf = NULL;
893                 if (xfer->rx_buf == master->dummy_rx)
894                         xfer->rx_buf = NULL;
895         }
896
897         return __spi_unmap_msg(master, msg);
898 }
899
900 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
901 {
902         struct spi_transfer *xfer;
903         void *tmp;
904         unsigned int max_tx, max_rx;
905
906         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
907                 max_tx = 0;
908                 max_rx = 0;
909
910                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
911                         if ((master->flags & SPI_MASTER_MUST_TX) &&
912                             !xfer->tx_buf)
913                                 max_tx = max(xfer->len, max_tx);
914                         if ((master->flags & SPI_MASTER_MUST_RX) &&
915                             !xfer->rx_buf)
916                                 max_rx = max(xfer->len, max_rx);
917                 }
918
919                 if (max_tx) {
920                         tmp = krealloc(master->dummy_tx, max_tx,
921                                        GFP_KERNEL | GFP_DMA);
922                         if (!tmp)
923                                 return -ENOMEM;
924                         master->dummy_tx = tmp;
925                         memset(tmp, 0, max_tx);
926                 }
927
928                 if (max_rx) {
929                         tmp = krealloc(master->dummy_rx, max_rx,
930                                        GFP_KERNEL | GFP_DMA);
931                         if (!tmp)
932                                 return -ENOMEM;
933                         master->dummy_rx = tmp;
934                 }
935
936                 if (max_tx || max_rx) {
937                         list_for_each_entry(xfer, &msg->transfers,
938                                             transfer_list) {
939                                 if (!xfer->tx_buf)
940                                         xfer->tx_buf = master->dummy_tx;
941                                 if (!xfer->rx_buf)
942                                         xfer->rx_buf = master->dummy_rx;
943                         }
944                 }
945         }
946
947         return __spi_map_msg(master, msg);
948 }
949
950 /*
951  * spi_transfer_one_message - Default implementation of transfer_one_message()
952  *
953  * This is a standard implementation of transfer_one_message() for
954  * drivers which implement a transfer_one() operation.  It provides
955  * standard handling of delays and chip select management.
956  */
957 static int spi_transfer_one_message(struct spi_master *master,
958                                     struct spi_message *msg)
959 {
960         struct spi_transfer *xfer;
961         bool keep_cs = false;
962         int ret = 0;
963         unsigned long ms = 1;
964         struct spi_statistics *statm = &master->statistics;
965         struct spi_statistics *stats = &msg->spi->statistics;
966
967         spi_set_cs(msg->spi, true);
968
969         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
970         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
971
972         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
973                 trace_spi_transfer_start(msg, xfer);
974
975                 spi_statistics_add_transfer_stats(statm, xfer, master);
976                 spi_statistics_add_transfer_stats(stats, xfer, master);
977
978                 if (xfer->tx_buf || xfer->rx_buf) {
979                         reinit_completion(&master->xfer_completion);
980
981                         ret = master->transfer_one(master, msg->spi, xfer);
982                         if (ret < 0) {
983                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
984                                                                errors);
985                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
986                                                                errors);
987                                 dev_err(&msg->spi->dev,
988                                         "SPI transfer failed: %d\n", ret);
989                                 goto out;
990                         }
991
992                         if (ret > 0) {
993                                 ret = 0;
994                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
995                                 ms += ms + 100; /* some tolerance */
996
997                                 ms = wait_for_completion_timeout(&master->xfer_completion,
998                                                                  msecs_to_jiffies(ms));
999                         }
1000
1001                         if (ms == 0) {
1002                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1003                                                                timedout);
1004                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1005                                                                timedout);
1006                                 dev_err(&msg->spi->dev,
1007                                         "SPI transfer timed out\n");
1008                                 msg->status = -ETIMEDOUT;
1009                         }
1010                 } else {
1011                         if (xfer->len)
1012                                 dev_err(&msg->spi->dev,
1013                                         "Bufferless transfer has length %u\n",
1014                                         xfer->len);
1015                 }
1016
1017                 trace_spi_transfer_stop(msg, xfer);
1018
1019                 if (msg->status != -EINPROGRESS)
1020                         goto out;
1021
1022                 if (xfer->delay_usecs)
1023                         udelay(xfer->delay_usecs);
1024
1025                 if (xfer->cs_change) {
1026                         if (list_is_last(&xfer->transfer_list,
1027                                          &msg->transfers)) {
1028                                 keep_cs = true;
1029                         } else {
1030                                 spi_set_cs(msg->spi, false);
1031                                 udelay(10);
1032                                 spi_set_cs(msg->spi, true);
1033                         }
1034                 }
1035
1036                 msg->actual_length += xfer->len;
1037         }
1038
1039 out:
1040         if (ret != 0 || !keep_cs)
1041                 spi_set_cs(msg->spi, false);
1042
1043         if (msg->status == -EINPROGRESS)
1044                 msg->status = ret;
1045
1046         if (msg->status && master->handle_err)
1047                 master->handle_err(master, msg);
1048
1049         spi_res_release(master, msg);
1050
1051         spi_finalize_current_message(master);
1052
1053         return ret;
1054 }
1055
1056 /**
1057  * spi_finalize_current_transfer - report completion of a transfer
1058  * @master: the master reporting completion
1059  *
1060  * Called by SPI drivers using the core transfer_one_message()
1061  * implementation to notify it that the current interrupt driven
1062  * transfer has finished and the next one may be scheduled.
1063  */
1064 void spi_finalize_current_transfer(struct spi_master *master)
1065 {
1066         complete(&master->xfer_completion);
1067 }
1068 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1069
1070 /**
1071  * __spi_pump_messages - function which processes spi message queue
1072  * @master: master to process queue for
1073  * @in_kthread: true if we are in the context of the message pump thread
1074  *
1075  * This function checks if there is any spi message in the queue that
1076  * needs processing and if so call out to the driver to initialize hardware
1077  * and transfer each message.
1078  *
1079  * Note that it is called both from the kthread itself and also from
1080  * inside spi_sync(); the queue extraction handling at the top of the
1081  * function should deal with this safely.
1082  */
1083 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1084 {
1085         unsigned long flags;
1086         bool was_busy = false;
1087         int ret;
1088
1089         /* Lock queue */
1090         spin_lock_irqsave(&master->queue_lock, flags);
1091
1092         /* Make sure we are not already running a message */
1093         if (master->cur_msg) {
1094                 spin_unlock_irqrestore(&master->queue_lock, flags);
1095                 return;
1096         }
1097
1098         /* If another context is idling the device then defer */
1099         if (master->idling) {
1100                 queue_kthread_work(&master->kworker, &master->pump_messages);
1101                 spin_unlock_irqrestore(&master->queue_lock, flags);
1102                 return;
1103         }
1104
1105         /* Check if the queue is idle */
1106         if (list_empty(&master->queue) || !master->running) {
1107                 if (!master->busy) {
1108                         spin_unlock_irqrestore(&master->queue_lock, flags);
1109                         return;
1110                 }
1111
1112                 /* Only do teardown in the thread */
1113                 if (!in_kthread) {
1114                         queue_kthread_work(&master->kworker,
1115                                            &master->pump_messages);
1116                         spin_unlock_irqrestore(&master->queue_lock, flags);
1117                         return;
1118                 }
1119
1120                 master->busy = false;
1121                 master->idling = true;
1122                 spin_unlock_irqrestore(&master->queue_lock, flags);
1123
1124                 kfree(master->dummy_rx);
1125                 master->dummy_rx = NULL;
1126                 kfree(master->dummy_tx);
1127                 master->dummy_tx = NULL;
1128                 if (master->unprepare_transfer_hardware &&
1129                     master->unprepare_transfer_hardware(master))
1130                         dev_err(&master->dev,
1131                                 "failed to unprepare transfer hardware\n");
1132                 if (master->auto_runtime_pm) {
1133                         pm_runtime_mark_last_busy(master->dev.parent);
1134                         pm_runtime_put_autosuspend(master->dev.parent);
1135                 }
1136                 trace_spi_master_idle(master);
1137
1138                 spin_lock_irqsave(&master->queue_lock, flags);
1139                 master->idling = false;
1140                 spin_unlock_irqrestore(&master->queue_lock, flags);
1141                 return;
1142         }
1143
1144         /* Extract head of queue */
1145         master->cur_msg =
1146                 list_first_entry(&master->queue, struct spi_message, queue);
1147
1148         list_del_init(&master->cur_msg->queue);
1149         if (master->busy)
1150                 was_busy = true;
1151         else
1152                 master->busy = true;
1153         spin_unlock_irqrestore(&master->queue_lock, flags);
1154
1155         mutex_lock(&master->io_mutex);
1156
1157         if (!was_busy && master->auto_runtime_pm) {
1158                 ret = pm_runtime_get_sync(master->dev.parent);
1159                 if (ret < 0) {
1160                         dev_err(&master->dev, "Failed to power device: %d\n",
1161                                 ret);
1162                         return;
1163                 }
1164         }
1165
1166         if (!was_busy)
1167                 trace_spi_master_busy(master);
1168
1169         if (!was_busy && master->prepare_transfer_hardware) {
1170                 ret = master->prepare_transfer_hardware(master);
1171                 if (ret) {
1172                         dev_err(&master->dev,
1173                                 "failed to prepare transfer hardware\n");
1174
1175                         if (master->auto_runtime_pm)
1176                                 pm_runtime_put(master->dev.parent);
1177                         return;
1178                 }
1179         }
1180
1181         trace_spi_message_start(master->cur_msg);
1182
1183         if (master->prepare_message) {
1184                 ret = master->prepare_message(master, master->cur_msg);
1185                 if (ret) {
1186                         dev_err(&master->dev,
1187                                 "failed to prepare message: %d\n", ret);
1188                         master->cur_msg->status = ret;
1189                         spi_finalize_current_message(master);
1190                         goto out;
1191                 }
1192                 master->cur_msg_prepared = true;
1193         }
1194
1195         ret = spi_map_msg(master, master->cur_msg);
1196         if (ret) {
1197                 master->cur_msg->status = ret;
1198                 spi_finalize_current_message(master);
1199                 goto out;
1200         }
1201
1202         ret = master->transfer_one_message(master, master->cur_msg);
1203         if (ret) {
1204                 dev_err(&master->dev,
1205                         "failed to transfer one message from queue\n");
1206                 goto out;
1207         }
1208
1209 out:
1210         mutex_unlock(&master->io_mutex);
1211
1212         /* Prod the scheduler in case transfer_one() was busy waiting */
1213         if (!ret)
1214                 cond_resched();
1215 }
1216
1217 /**
1218  * spi_pump_messages - kthread work function which processes spi message queue
1219  * @work: pointer to kthread work struct contained in the master struct
1220  */
1221 static void spi_pump_messages(struct kthread_work *work)
1222 {
1223         struct spi_master *master =
1224                 container_of(work, struct spi_master, pump_messages);
1225
1226         __spi_pump_messages(master, true);
1227 }
1228
1229 static int spi_init_queue(struct spi_master *master)
1230 {
1231         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1232
1233         master->running = false;
1234         master->busy = false;
1235
1236         init_kthread_worker(&master->kworker);
1237         master->kworker_task = kthread_run(kthread_worker_fn,
1238                                            &master->kworker, "%s",
1239                                            dev_name(&master->dev));
1240         if (IS_ERR(master->kworker_task)) {
1241                 dev_err(&master->dev, "failed to create message pump task\n");
1242                 return PTR_ERR(master->kworker_task);
1243         }
1244         init_kthread_work(&master->pump_messages, spi_pump_messages);
1245
1246         /*
1247          * Master config will indicate if this controller should run the
1248          * message pump with high (realtime) priority to reduce the transfer
1249          * latency on the bus by minimising the delay between a transfer
1250          * request and the scheduling of the message pump thread. Without this
1251          * setting the message pump thread will remain at default priority.
1252          */
1253         if (master->rt) {
1254                 dev_info(&master->dev,
1255                         "will run message pump with realtime priority\n");
1256                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1257         }
1258
1259         return 0;
1260 }
1261
1262 /**
1263  * spi_get_next_queued_message() - called by driver to check for queued
1264  * messages
1265  * @master: the master to check for queued messages
1266  *
1267  * If there are more messages in the queue, the next message is returned from
1268  * this call.
1269  *
1270  * Return: the next message in the queue, else NULL if the queue is empty.
1271  */
1272 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1273 {
1274         struct spi_message *next;
1275         unsigned long flags;
1276
1277         /* get a pointer to the next message, if any */
1278         spin_lock_irqsave(&master->queue_lock, flags);
1279         next = list_first_entry_or_null(&master->queue, struct spi_message,
1280                                         queue);
1281         spin_unlock_irqrestore(&master->queue_lock, flags);
1282
1283         return next;
1284 }
1285 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1286
1287 /**
1288  * spi_finalize_current_message() - the current message is complete
1289  * @master: the master to return the message to
1290  *
1291  * Called by the driver to notify the core that the message in the front of the
1292  * queue is complete and can be removed from the queue.
1293  */
1294 void spi_finalize_current_message(struct spi_master *master)
1295 {
1296         struct spi_message *mesg;
1297         unsigned long flags;
1298         int ret;
1299
1300         spin_lock_irqsave(&master->queue_lock, flags);
1301         mesg = master->cur_msg;
1302         spin_unlock_irqrestore(&master->queue_lock, flags);
1303
1304         spi_unmap_msg(master, mesg);
1305
1306         if (master->cur_msg_prepared && master->unprepare_message) {
1307                 ret = master->unprepare_message(master, mesg);
1308                 if (ret) {
1309                         dev_err(&master->dev,
1310                                 "failed to unprepare message: %d\n", ret);
1311                 }
1312         }
1313
1314         spin_lock_irqsave(&master->queue_lock, flags);
1315         master->cur_msg = NULL;
1316         master->cur_msg_prepared = false;
1317         queue_kthread_work(&master->kworker, &master->pump_messages);
1318         spin_unlock_irqrestore(&master->queue_lock, flags);
1319
1320         trace_spi_message_done(mesg);
1321
1322         mesg->state = NULL;
1323         if (mesg->complete)
1324                 mesg->complete(mesg->context);
1325 }
1326 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1327
1328 static int spi_start_queue(struct spi_master *master)
1329 {
1330         unsigned long flags;
1331
1332         spin_lock_irqsave(&master->queue_lock, flags);
1333
1334         if (master->running || master->busy) {
1335                 spin_unlock_irqrestore(&master->queue_lock, flags);
1336                 return -EBUSY;
1337         }
1338
1339         master->running = true;
1340         master->cur_msg = NULL;
1341         spin_unlock_irqrestore(&master->queue_lock, flags);
1342
1343         queue_kthread_work(&master->kworker, &master->pump_messages);
1344
1345         return 0;
1346 }
1347
1348 static int spi_stop_queue(struct spi_master *master)
1349 {
1350         unsigned long flags;
1351         unsigned limit = 500;
1352         int ret = 0;
1353
1354         spin_lock_irqsave(&master->queue_lock, flags);
1355
1356         /*
1357          * This is a bit lame, but is optimized for the common execution path.
1358          * A wait_queue on the master->busy could be used, but then the common
1359          * execution path (pump_messages) would be required to call wake_up or
1360          * friends on every SPI message. Do this instead.
1361          */
1362         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1363                 spin_unlock_irqrestore(&master->queue_lock, flags);
1364                 usleep_range(10000, 11000);
1365                 spin_lock_irqsave(&master->queue_lock, flags);
1366         }
1367
1368         if (!list_empty(&master->queue) || master->busy)
1369                 ret = -EBUSY;
1370         else
1371                 master->running = false;
1372
1373         spin_unlock_irqrestore(&master->queue_lock, flags);
1374
1375         if (ret) {
1376                 dev_warn(&master->dev,
1377                          "could not stop message queue\n");
1378                 return ret;
1379         }
1380         return ret;
1381 }
1382
1383 static int spi_destroy_queue(struct spi_master *master)
1384 {
1385         int ret;
1386
1387         ret = spi_stop_queue(master);
1388
1389         /*
1390          * flush_kthread_worker will block until all work is done.
1391          * If the reason that stop_queue timed out is that the work will never
1392          * finish, then it does no good to call flush/stop thread, so
1393          * return anyway.
1394          */
1395         if (ret) {
1396                 dev_err(&master->dev, "problem destroying queue\n");
1397                 return ret;
1398         }
1399
1400         flush_kthread_worker(&master->kworker);
1401         kthread_stop(master->kworker_task);
1402
1403         return 0;
1404 }
1405
1406 static int __spi_queued_transfer(struct spi_device *spi,
1407                                  struct spi_message *msg,
1408                                  bool need_pump)
1409 {
1410         struct spi_master *master = spi->master;
1411         unsigned long flags;
1412
1413         spin_lock_irqsave(&master->queue_lock, flags);
1414
1415         if (!master->running) {
1416                 spin_unlock_irqrestore(&master->queue_lock, flags);
1417                 return -ESHUTDOWN;
1418         }
1419         msg->actual_length = 0;
1420         msg->status = -EINPROGRESS;
1421
1422         list_add_tail(&msg->queue, &master->queue);
1423         if (!master->busy && need_pump)
1424                 queue_kthread_work(&master->kworker, &master->pump_messages);
1425
1426         spin_unlock_irqrestore(&master->queue_lock, flags);
1427         return 0;
1428 }
1429
1430 /**
1431  * spi_queued_transfer - transfer function for queued transfers
1432  * @spi: spi device which is requesting transfer
1433  * @msg: spi message which is to handled is queued to driver queue
1434  *
1435  * Return: zero on success, else a negative error code.
1436  */
1437 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1438 {
1439         return __spi_queued_transfer(spi, msg, true);
1440 }
1441
1442 static int spi_master_initialize_queue(struct spi_master *master)
1443 {
1444         int ret;
1445
1446         master->transfer = spi_queued_transfer;
1447         if (!master->transfer_one_message)
1448                 master->transfer_one_message = spi_transfer_one_message;
1449
1450         /* Initialize and start queue */
1451         ret = spi_init_queue(master);
1452         if (ret) {
1453                 dev_err(&master->dev, "problem initializing queue\n");
1454                 goto err_init_queue;
1455         }
1456         master->queued = true;
1457         ret = spi_start_queue(master);
1458         if (ret) {
1459                 dev_err(&master->dev, "problem starting queue\n");
1460                 goto err_start_queue;
1461         }
1462
1463         return 0;
1464
1465 err_start_queue:
1466         spi_destroy_queue(master);
1467 err_init_queue:
1468         return ret;
1469 }
1470
1471 /*-------------------------------------------------------------------------*/
1472
1473 #if defined(CONFIG_OF)
1474 static struct spi_device *
1475 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1476 {
1477         struct spi_device *spi;
1478         int rc;
1479         u32 value;
1480
1481         /* Alloc an spi_device */
1482         spi = spi_alloc_device(master);
1483         if (!spi) {
1484                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1485                         nc->full_name);
1486                 rc = -ENOMEM;
1487                 goto err_out;
1488         }
1489
1490         /* Select device driver */
1491         rc = of_modalias_node(nc, spi->modalias,
1492                                 sizeof(spi->modalias));
1493         if (rc < 0) {
1494                 dev_err(&master->dev, "cannot find modalias for %s\n",
1495                         nc->full_name);
1496                 goto err_out;
1497         }
1498
1499         /* Device address */
1500         rc = of_property_read_u32(nc, "reg", &value);
1501         if (rc) {
1502                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1503                         nc->full_name, rc);
1504                 goto err_out;
1505         }
1506         spi->chip_select = value;
1507
1508         /* Mode (clock phase/polarity/etc.) */
1509         if (of_find_property(nc, "spi-cpha", NULL))
1510                 spi->mode |= SPI_CPHA;
1511         if (of_find_property(nc, "spi-cpol", NULL))
1512                 spi->mode |= SPI_CPOL;
1513         if (of_find_property(nc, "spi-cs-high", NULL))
1514                 spi->mode |= SPI_CS_HIGH;
1515         if (of_find_property(nc, "spi-3wire", NULL))
1516                 spi->mode |= SPI_3WIRE;
1517         if (of_find_property(nc, "spi-lsb-first", NULL))
1518                 spi->mode |= SPI_LSB_FIRST;
1519
1520         /* Device DUAL/QUAD mode */
1521         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1522                 switch (value) {
1523                 case 1:
1524                         break;
1525                 case 2:
1526                         spi->mode |= SPI_TX_DUAL;
1527                         break;
1528                 case 4:
1529                         spi->mode |= SPI_TX_QUAD;
1530                         break;
1531                 default:
1532                         dev_warn(&master->dev,
1533                                 "spi-tx-bus-width %d not supported\n",
1534                                 value);
1535                         break;
1536                 }
1537         }
1538
1539         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1540                 switch (value) {
1541                 case 1:
1542                         break;
1543                 case 2:
1544                         spi->mode |= SPI_RX_DUAL;
1545                         break;
1546                 case 4:
1547                         spi->mode |= SPI_RX_QUAD;
1548                         break;
1549                 default:
1550                         dev_warn(&master->dev,
1551                                 "spi-rx-bus-width %d not supported\n",
1552                                 value);
1553                         break;
1554                 }
1555         }
1556
1557         /* Device speed */
1558         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1559         if (rc) {
1560                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1561                         nc->full_name, rc);
1562                 goto err_out;
1563         }
1564         spi->max_speed_hz = value;
1565
1566         /* Store a pointer to the node in the device structure */
1567         of_node_get(nc);
1568         spi->dev.of_node = nc;
1569
1570         /* Register the new device */
1571         rc = spi_add_device(spi);
1572         if (rc) {
1573                 dev_err(&master->dev, "spi_device register error %s\n",
1574                         nc->full_name);
1575                 goto err_out;
1576         }
1577
1578         return spi;
1579
1580 err_out:
1581         spi_dev_put(spi);
1582         return ERR_PTR(rc);
1583 }
1584
1585 /**
1586  * of_register_spi_devices() - Register child devices onto the SPI bus
1587  * @master:     Pointer to spi_master device
1588  *
1589  * Registers an spi_device for each child node of master node which has a 'reg'
1590  * property.
1591  */
1592 static void of_register_spi_devices(struct spi_master *master)
1593 {
1594         struct spi_device *spi;
1595         struct device_node *nc;
1596
1597         if (!master->dev.of_node)
1598                 return;
1599
1600         for_each_available_child_of_node(master->dev.of_node, nc) {
1601                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1602                         continue;
1603                 spi = of_register_spi_device(master, nc);
1604                 if (IS_ERR(spi))
1605                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1606                                 nc->full_name);
1607         }
1608 }
1609 #else
1610 static void of_register_spi_devices(struct spi_master *master) { }
1611 #endif
1612
1613 #ifdef CONFIG_ACPI
1614 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1615 {
1616         struct spi_device *spi = data;
1617         struct spi_master *master = spi->master;
1618
1619         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1620                 struct acpi_resource_spi_serialbus *sb;
1621
1622                 sb = &ares->data.spi_serial_bus;
1623                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1624                         /*
1625                          * ACPI DeviceSelection numbering is handled by the
1626                          * host controller driver in Windows and can vary
1627                          * from driver to driver. In Linux we always expect
1628                          * 0 .. max - 1 so we need to ask the driver to
1629                          * translate between the two schemes.
1630                          */
1631                         if (master->fw_translate_cs) {
1632                                 int cs = master->fw_translate_cs(master,
1633                                                 sb->device_selection);
1634                                 if (cs < 0)
1635                                         return cs;
1636                                 spi->chip_select = cs;
1637                         } else {
1638                                 spi->chip_select = sb->device_selection;
1639                         }
1640
1641                         spi->max_speed_hz = sb->connection_speed;
1642
1643                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1644                                 spi->mode |= SPI_CPHA;
1645                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1646                                 spi->mode |= SPI_CPOL;
1647                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1648                                 spi->mode |= SPI_CS_HIGH;
1649                 }
1650         } else if (spi->irq < 0) {
1651                 struct resource r;
1652
1653                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1654                         spi->irq = r.start;
1655         }
1656
1657         /* Always tell the ACPI core to skip this resource */
1658         return 1;
1659 }
1660
1661 static acpi_status acpi_register_spi_device(struct spi_master *master,
1662                                             struct acpi_device *adev)
1663 {
1664         struct list_head resource_list;
1665         struct spi_device *spi;
1666         int ret;
1667
1668         if (acpi_bus_get_status(adev) || !adev->status.present ||
1669             acpi_device_enumerated(adev))
1670                 return AE_OK;
1671
1672         spi = spi_alloc_device(master);
1673         if (!spi) {
1674                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1675                         dev_name(&adev->dev));
1676                 return AE_NO_MEMORY;
1677         }
1678
1679         ACPI_COMPANION_SET(&spi->dev, adev);
1680         spi->irq = -1;
1681
1682         INIT_LIST_HEAD(&resource_list);
1683         ret = acpi_dev_get_resources(adev, &resource_list,
1684                                      acpi_spi_add_resource, spi);
1685         acpi_dev_free_resource_list(&resource_list);
1686
1687         if (ret < 0 || !spi->max_speed_hz) {
1688                 spi_dev_put(spi);
1689                 return AE_OK;
1690         }
1691
1692         if (spi->irq < 0)
1693                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1694
1695         acpi_device_set_enumerated(adev);
1696
1697         adev->power.flags.ignore_parent = true;
1698         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1699         if (spi_add_device(spi)) {
1700                 adev->power.flags.ignore_parent = false;
1701                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1702                         dev_name(&adev->dev));
1703                 spi_dev_put(spi);
1704         }
1705
1706         return AE_OK;
1707 }
1708
1709 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1710                                        void *data, void **return_value)
1711 {
1712         struct spi_master *master = data;
1713         struct acpi_device *adev;
1714
1715         if (acpi_bus_get_device(handle, &adev))
1716                 return AE_OK;
1717
1718         return acpi_register_spi_device(master, adev);
1719 }
1720
1721 static void acpi_register_spi_devices(struct spi_master *master)
1722 {
1723         acpi_status status;
1724         acpi_handle handle;
1725
1726         handle = ACPI_HANDLE(master->dev.parent);
1727         if (!handle)
1728                 return;
1729
1730         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1731                                      acpi_spi_add_device, NULL,
1732                                      master, NULL);
1733         if (ACPI_FAILURE(status))
1734                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1735 }
1736 #else
1737 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1738 #endif /* CONFIG_ACPI */
1739
1740 static void spi_master_release(struct device *dev)
1741 {
1742         struct spi_master *master;
1743
1744         master = container_of(dev, struct spi_master, dev);
1745         kfree(master);
1746 }
1747
1748 static struct class spi_master_class = {
1749         .name           = "spi_master",
1750         .owner          = THIS_MODULE,
1751         .dev_release    = spi_master_release,
1752         .dev_groups     = spi_master_groups,
1753 };
1754
1755
1756 /**
1757  * spi_alloc_master - allocate SPI master controller
1758  * @dev: the controller, possibly using the platform_bus
1759  * @size: how much zeroed driver-private data to allocate; the pointer to this
1760  *      memory is in the driver_data field of the returned device,
1761  *      accessible with spi_master_get_devdata().
1762  * Context: can sleep
1763  *
1764  * This call is used only by SPI master controller drivers, which are the
1765  * only ones directly touching chip registers.  It's how they allocate
1766  * an spi_master structure, prior to calling spi_register_master().
1767  *
1768  * This must be called from context that can sleep.
1769  *
1770  * The caller is responsible for assigning the bus number and initializing
1771  * the master's methods before calling spi_register_master(); and (after errors
1772  * adding the device) calling spi_master_put() to prevent a memory leak.
1773  *
1774  * Return: the SPI master structure on success, else NULL.
1775  */
1776 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1777 {
1778         struct spi_master       *master;
1779
1780         if (!dev)
1781                 return NULL;
1782
1783         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1784         if (!master)
1785                 return NULL;
1786
1787         device_initialize(&master->dev);
1788         master->bus_num = -1;
1789         master->num_chipselect = 1;
1790         master->dev.class = &spi_master_class;
1791         master->dev.parent = dev;
1792         pm_suspend_ignore_children(&master->dev, true);
1793         spi_master_set_devdata(master, &master[1]);
1794
1795         return master;
1796 }
1797 EXPORT_SYMBOL_GPL(spi_alloc_master);
1798
1799 #ifdef CONFIG_OF
1800 static int of_spi_register_master(struct spi_master *master)
1801 {
1802         int nb, i, *cs;
1803         struct device_node *np = master->dev.of_node;
1804
1805         if (!np)
1806                 return 0;
1807
1808         nb = of_gpio_named_count(np, "cs-gpios");
1809         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1810
1811         /* Return error only for an incorrectly formed cs-gpios property */
1812         if (nb == 0 || nb == -ENOENT)
1813                 return 0;
1814         else if (nb < 0)
1815                 return nb;
1816
1817         cs = devm_kzalloc(&master->dev,
1818                           sizeof(int) * master->num_chipselect,
1819                           GFP_KERNEL);
1820         master->cs_gpios = cs;
1821
1822         if (!master->cs_gpios)
1823                 return -ENOMEM;
1824
1825         for (i = 0; i < master->num_chipselect; i++)
1826                 cs[i] = -ENOENT;
1827
1828         for (i = 0; i < nb; i++)
1829                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1830
1831         return 0;
1832 }
1833 #else
1834 static int of_spi_register_master(struct spi_master *master)
1835 {
1836         return 0;
1837 }
1838 #endif
1839
1840 /**
1841  * spi_register_master - register SPI master controller
1842  * @master: initialized master, originally from spi_alloc_master()
1843  * Context: can sleep
1844  *
1845  * SPI master controllers connect to their drivers using some non-SPI bus,
1846  * such as the platform bus.  The final stage of probe() in that code
1847  * includes calling spi_register_master() to hook up to this SPI bus glue.
1848  *
1849  * SPI controllers use board specific (often SOC specific) bus numbers,
1850  * and board-specific addressing for SPI devices combines those numbers
1851  * with chip select numbers.  Since SPI does not directly support dynamic
1852  * device identification, boards need configuration tables telling which
1853  * chip is at which address.
1854  *
1855  * This must be called from context that can sleep.  It returns zero on
1856  * success, else a negative error code (dropping the master's refcount).
1857  * After a successful return, the caller is responsible for calling
1858  * spi_unregister_master().
1859  *
1860  * Return: zero on success, else a negative error code.
1861  */
1862 int spi_register_master(struct spi_master *master)
1863 {
1864         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1865         struct device           *dev = master->dev.parent;
1866         struct boardinfo        *bi;
1867         int                     status = -ENODEV;
1868         int                     dynamic = 0;
1869
1870         if (!dev)
1871                 return -ENODEV;
1872
1873         status = of_spi_register_master(master);
1874         if (status)
1875                 return status;
1876
1877         /* even if it's just one always-selected device, there must
1878          * be at least one chipselect
1879          */
1880         if (master->num_chipselect == 0)
1881                 return -EINVAL;
1882
1883         if ((master->bus_num < 0) && master->dev.of_node)
1884                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1885
1886         /* convention:  dynamically assigned bus IDs count down from the max */
1887         if (master->bus_num < 0) {
1888                 /* FIXME switch to an IDR based scheme, something like
1889                  * I2C now uses, so we can't run out of "dynamic" IDs
1890                  */
1891                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1892                 dynamic = 1;
1893         }
1894
1895         INIT_LIST_HEAD(&master->queue);
1896         spin_lock_init(&master->queue_lock);
1897         spin_lock_init(&master->bus_lock_spinlock);
1898         mutex_init(&master->bus_lock_mutex);
1899         mutex_init(&master->io_mutex);
1900         master->bus_lock_flag = 0;
1901         init_completion(&master->xfer_completion);
1902         if (!master->max_dma_len)
1903                 master->max_dma_len = INT_MAX;
1904
1905         /* register the device, then userspace will see it.
1906          * registration fails if the bus ID is in use.
1907          */
1908         dev_set_name(&master->dev, "spi%u", master->bus_num);
1909         status = device_add(&master->dev);
1910         if (status < 0)
1911                 goto done;
1912         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1913                         dynamic ? " (dynamic)" : "");
1914
1915         /* If we're using a queued driver, start the queue */
1916         if (master->transfer)
1917                 dev_info(dev, "master is unqueued, this is deprecated\n");
1918         else {
1919                 status = spi_master_initialize_queue(master);
1920                 if (status) {
1921                         device_del(&master->dev);
1922                         goto done;
1923                 }
1924         }
1925         /* add statistics */
1926         spin_lock_init(&master->statistics.lock);
1927
1928         mutex_lock(&board_lock);
1929         list_add_tail(&master->list, &spi_master_list);
1930         list_for_each_entry(bi, &board_list, list)
1931                 spi_match_master_to_boardinfo(master, &bi->board_info);
1932         mutex_unlock(&board_lock);
1933
1934         /* Register devices from the device tree and ACPI */
1935         of_register_spi_devices(master);
1936         acpi_register_spi_devices(master);
1937 done:
1938         return status;
1939 }
1940 EXPORT_SYMBOL_GPL(spi_register_master);
1941
1942 static void devm_spi_unregister(struct device *dev, void *res)
1943 {
1944         spi_unregister_master(*(struct spi_master **)res);
1945 }
1946
1947 /**
1948  * dev_spi_register_master - register managed SPI master controller
1949  * @dev:    device managing SPI master
1950  * @master: initialized master, originally from spi_alloc_master()
1951  * Context: can sleep
1952  *
1953  * Register a SPI device as with spi_register_master() which will
1954  * automatically be unregister
1955  *
1956  * Return: zero on success, else a negative error code.
1957  */
1958 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1959 {
1960         struct spi_master **ptr;
1961         int ret;
1962
1963         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1964         if (!ptr)
1965                 return -ENOMEM;
1966
1967         ret = spi_register_master(master);
1968         if (!ret) {
1969                 *ptr = master;
1970                 devres_add(dev, ptr);
1971         } else {
1972                 devres_free(ptr);
1973         }
1974
1975         return ret;
1976 }
1977 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1978
1979 static int __unregister(struct device *dev, void *null)
1980 {
1981         spi_unregister_device(to_spi_device(dev));
1982         return 0;
1983 }
1984
1985 /**
1986  * spi_unregister_master - unregister SPI master controller
1987  * @master: the master being unregistered
1988  * Context: can sleep
1989  *
1990  * This call is used only by SPI master controller drivers, which are the
1991  * only ones directly touching chip registers.
1992  *
1993  * This must be called from context that can sleep.
1994  */
1995 void spi_unregister_master(struct spi_master *master)
1996 {
1997         int dummy;
1998
1999         if (master->queued) {
2000                 if (spi_destroy_queue(master))
2001                         dev_err(&master->dev, "queue remove failed\n");
2002         }
2003
2004         mutex_lock(&board_lock);
2005         list_del(&master->list);
2006         mutex_unlock(&board_lock);
2007
2008         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2009         device_unregister(&master->dev);
2010 }
2011 EXPORT_SYMBOL_GPL(spi_unregister_master);
2012
2013 int spi_master_suspend(struct spi_master *master)
2014 {
2015         int ret;
2016
2017         /* Basically no-ops for non-queued masters */
2018         if (!master->queued)
2019                 return 0;
2020
2021         ret = spi_stop_queue(master);
2022         if (ret)
2023                 dev_err(&master->dev, "queue stop failed\n");
2024
2025         return ret;
2026 }
2027 EXPORT_SYMBOL_GPL(spi_master_suspend);
2028
2029 int spi_master_resume(struct spi_master *master)
2030 {
2031         int ret;
2032
2033         if (!master->queued)
2034                 return 0;
2035
2036         ret = spi_start_queue(master);
2037         if (ret)
2038                 dev_err(&master->dev, "queue restart failed\n");
2039
2040         return ret;
2041 }
2042 EXPORT_SYMBOL_GPL(spi_master_resume);
2043
2044 static int __spi_master_match(struct device *dev, const void *data)
2045 {
2046         struct spi_master *m;
2047         const u16 *bus_num = data;
2048
2049         m = container_of(dev, struct spi_master, dev);
2050         return m->bus_num == *bus_num;
2051 }
2052
2053 /**
2054  * spi_busnum_to_master - look up master associated with bus_num
2055  * @bus_num: the master's bus number
2056  * Context: can sleep
2057  *
2058  * This call may be used with devices that are registered after
2059  * arch init time.  It returns a refcounted pointer to the relevant
2060  * spi_master (which the caller must release), or NULL if there is
2061  * no such master registered.
2062  *
2063  * Return: the SPI master structure on success, else NULL.
2064  */
2065 struct spi_master *spi_busnum_to_master(u16 bus_num)
2066 {
2067         struct device           *dev;
2068         struct spi_master       *master = NULL;
2069
2070         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2071                                 __spi_master_match);
2072         if (dev)
2073                 master = container_of(dev, struct spi_master, dev);
2074         /* reference got in class_find_device */
2075         return master;
2076 }
2077 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2078
2079 /*-------------------------------------------------------------------------*/
2080
2081 /* Core methods for SPI resource management */
2082
2083 /**
2084  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2085  *                 during the processing of a spi_message while using
2086  *                 spi_transfer_one
2087  * @spi:     the spi device for which we allocate memory
2088  * @release: the release code to execute for this resource
2089  * @size:    size to alloc and return
2090  * @gfp:     GFP allocation flags
2091  *
2092  * Return: the pointer to the allocated data
2093  *
2094  * This may get enhanced in the future to allocate from a memory pool
2095  * of the @spi_device or @spi_master to avoid repeated allocations.
2096  */
2097 void *spi_res_alloc(struct spi_device *spi,
2098                     spi_res_release_t release,
2099                     size_t size, gfp_t gfp)
2100 {
2101         struct spi_res *sres;
2102
2103         sres = kzalloc(sizeof(*sres) + size, gfp);
2104         if (!sres)
2105                 return NULL;
2106
2107         INIT_LIST_HEAD(&sres->entry);
2108         sres->release = release;
2109
2110         return sres->data;
2111 }
2112 EXPORT_SYMBOL_GPL(spi_res_alloc);
2113
2114 /**
2115  * spi_res_free - free an spi resource
2116  * @res: pointer to the custom data of a resource
2117  *
2118  */
2119 void spi_res_free(void *res)
2120 {
2121         struct spi_res *sres = container_of(res, struct spi_res, data);
2122
2123         if (!res)
2124                 return;
2125
2126         WARN_ON(!list_empty(&sres->entry));
2127         kfree(sres);
2128 }
2129 EXPORT_SYMBOL_GPL(spi_res_free);
2130
2131 /**
2132  * spi_res_add - add a spi_res to the spi_message
2133  * @message: the spi message
2134  * @res:     the spi_resource
2135  */
2136 void spi_res_add(struct spi_message *message, void *res)
2137 {
2138         struct spi_res *sres = container_of(res, struct spi_res, data);
2139
2140         WARN_ON(!list_empty(&sres->entry));
2141         list_add_tail(&sres->entry, &message->resources);
2142 }
2143 EXPORT_SYMBOL_GPL(spi_res_add);
2144
2145 /**
2146  * spi_res_release - release all spi resources for this message
2147  * @master:  the @spi_master
2148  * @message: the @spi_message
2149  */
2150 void spi_res_release(struct spi_master *master,
2151                      struct spi_message *message)
2152 {
2153         struct spi_res *res;
2154
2155         while (!list_empty(&message->resources)) {
2156                 res = list_last_entry(&message->resources,
2157                                       struct spi_res, entry);
2158
2159                 if (res->release)
2160                         res->release(master, message, res->data);
2161
2162                 list_del(&res->entry);
2163
2164                 kfree(res);
2165         }
2166 }
2167 EXPORT_SYMBOL_GPL(spi_res_release);
2168
2169 /*-------------------------------------------------------------------------*/
2170
2171 /* Core methods for spi_message alterations */
2172
2173 static void __spi_replace_transfers_release(struct spi_master *master,
2174                                             struct spi_message *msg,
2175                                             void *res)
2176 {
2177         struct spi_replaced_transfers *rxfer = res;
2178         size_t i;
2179
2180         /* call extra callback if requested */
2181         if (rxfer->release)
2182                 rxfer->release(master, msg, res);
2183
2184         /* insert replaced transfers back into the message */
2185         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2186
2187         /* remove the formerly inserted entries */
2188         for (i = 0; i < rxfer->inserted; i++)
2189                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2190 }
2191
2192 /**
2193  * spi_replace_transfers - replace transfers with several transfers
2194  *                         and register change with spi_message.resources
2195  * @msg:           the spi_message we work upon
2196  * @xfer_first:    the first spi_transfer we want to replace
2197  * @remove:        number of transfers to remove
2198  * @insert:        the number of transfers we want to insert instead
2199  * @release:       extra release code necessary in some circumstances
2200  * @extradatasize: extra data to allocate (with alignment guarantees
2201  *                 of struct @spi_transfer)
2202  * @gfp:           gfp flags
2203  *
2204  * Returns: pointer to @spi_replaced_transfers,
2205  *          PTR_ERR(...) in case of errors.
2206  */
2207 struct spi_replaced_transfers *spi_replace_transfers(
2208         struct spi_message *msg,
2209         struct spi_transfer *xfer_first,
2210         size_t remove,
2211         size_t insert,
2212         spi_replaced_release_t release,
2213         size_t extradatasize,
2214         gfp_t gfp)
2215 {
2216         struct spi_replaced_transfers *rxfer;
2217         struct spi_transfer *xfer;
2218         size_t i;
2219
2220         /* allocate the structure using spi_res */
2221         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2222                               insert * sizeof(struct spi_transfer)
2223                               + sizeof(struct spi_replaced_transfers)
2224                               + extradatasize,
2225                               gfp);
2226         if (!rxfer)
2227                 return ERR_PTR(-ENOMEM);
2228
2229         /* the release code to invoke before running the generic release */
2230         rxfer->release = release;
2231
2232         /* assign extradata */
2233         if (extradatasize)
2234                 rxfer->extradata =
2235                         &rxfer->inserted_transfers[insert];
2236
2237         /* init the replaced_transfers list */
2238         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2239
2240         /* assign the list_entry after which we should reinsert
2241          * the @replaced_transfers - it may be spi_message.messages!
2242          */
2243         rxfer->replaced_after = xfer_first->transfer_list.prev;
2244
2245         /* remove the requested number of transfers */
2246         for (i = 0; i < remove; i++) {
2247                 /* if the entry after replaced_after it is msg->transfers
2248                  * then we have been requested to remove more transfers
2249                  * than are in the list
2250                  */
2251                 if (rxfer->replaced_after->next == &msg->transfers) {
2252                         dev_err(&msg->spi->dev,
2253                                 "requested to remove more spi_transfers than are available\n");
2254                         /* insert replaced transfers back into the message */
2255                         list_splice(&rxfer->replaced_transfers,
2256                                     rxfer->replaced_after);
2257
2258                         /* free the spi_replace_transfer structure */
2259                         spi_res_free(rxfer);
2260
2261                         /* and return with an error */
2262                         return ERR_PTR(-EINVAL);
2263                 }
2264
2265                 /* remove the entry after replaced_after from list of
2266                  * transfers and add it to list of replaced_transfers
2267                  */
2268                 list_move_tail(rxfer->replaced_after->next,
2269                                &rxfer->replaced_transfers);
2270         }
2271
2272         /* create copy of the given xfer with identical settings
2273          * based on the first transfer to get removed
2274          */
2275         for (i = 0; i < insert; i++) {
2276                 /* we need to run in reverse order */
2277                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2278
2279                 /* copy all spi_transfer data */
2280                 memcpy(xfer, xfer_first, sizeof(*xfer));
2281
2282                 /* add to list */
2283                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2284
2285                 /* clear cs_change and delay_usecs for all but the last */
2286                 if (i) {
2287                         xfer->cs_change = false;
2288                         xfer->delay_usecs = 0;
2289                 }
2290         }
2291
2292         /* set up inserted */
2293         rxfer->inserted = insert;
2294
2295         /* and register it with spi_res/spi_message */
2296         spi_res_add(msg, rxfer);
2297
2298         return rxfer;
2299 }
2300 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2301
2302 static int __spi_split_transfer_maxsize(struct spi_master *master,
2303                                         struct spi_message *msg,
2304                                         struct spi_transfer **xferp,
2305                                         size_t maxsize,
2306                                         gfp_t gfp)
2307 {
2308         struct spi_transfer *xfer = *xferp, *xfers;
2309         struct spi_replaced_transfers *srt;
2310         size_t offset;
2311         size_t count, i;
2312
2313         /* warn once about this fact that we are splitting a transfer */
2314         dev_warn_once(&msg->spi->dev,
2315                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2316                       xfer->len, maxsize);
2317
2318         /* calculate how many we have to replace */
2319         count = DIV_ROUND_UP(xfer->len, maxsize);
2320
2321         /* create replacement */
2322         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2323         if (IS_ERR(srt))
2324                 return PTR_ERR(srt);
2325         xfers = srt->inserted_transfers;
2326
2327         /* now handle each of those newly inserted spi_transfers
2328          * note that the replacements spi_transfers all are preset
2329          * to the same values as *xferp, so tx_buf, rx_buf and len
2330          * are all identical (as well as most others)
2331          * so we just have to fix up len and the pointers.
2332          *
2333          * this also includes support for the depreciated
2334          * spi_message.is_dma_mapped interface
2335          */
2336
2337         /* the first transfer just needs the length modified, so we
2338          * run it outside the loop
2339          */
2340         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2341
2342         /* all the others need rx_buf/tx_buf also set */
2343         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2344                 /* update rx_buf, tx_buf and dma */
2345                 if (xfers[i].rx_buf)
2346                         xfers[i].rx_buf += offset;
2347                 if (xfers[i].rx_dma)
2348                         xfers[i].rx_dma += offset;
2349                 if (xfers[i].tx_buf)
2350                         xfers[i].tx_buf += offset;
2351                 if (xfers[i].tx_dma)
2352                         xfers[i].tx_dma += offset;
2353
2354                 /* update length */
2355                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2356         }
2357
2358         /* we set up xferp to the last entry we have inserted,
2359          * so that we skip those already split transfers
2360          */
2361         *xferp = &xfers[count - 1];
2362
2363         /* increment statistics counters */
2364         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2365                                        transfers_split_maxsize);
2366         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2367                                        transfers_split_maxsize);
2368
2369         return 0;
2370 }
2371
2372 /**
2373  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2374  *                              when an individual transfer exceeds a
2375  *                              certain size
2376  * @master:    the @spi_master for this transfer
2377  * @msg:   the @spi_message to transform
2378  * @maxsize:  the maximum when to apply this
2379  * @gfp: GFP allocation flags
2380  *
2381  * Return: status of transformation
2382  */
2383 int spi_split_transfers_maxsize(struct spi_master *master,
2384                                 struct spi_message *msg,
2385                                 size_t maxsize,
2386                                 gfp_t gfp)
2387 {
2388         struct spi_transfer *xfer;
2389         int ret;
2390
2391         /* iterate over the transfer_list,
2392          * but note that xfer is advanced to the last transfer inserted
2393          * to avoid checking sizes again unnecessarily (also xfer does
2394          * potentiall belong to a different list by the time the
2395          * replacement has happened
2396          */
2397         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2398                 if (xfer->len > maxsize) {
2399                         ret = __spi_split_transfer_maxsize(
2400                                 master, msg, &xfer, maxsize, gfp);
2401                         if (ret)
2402                                 return ret;
2403                 }
2404         }
2405
2406         return 0;
2407 }
2408 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2409
2410 /*-------------------------------------------------------------------------*/
2411
2412 /* Core methods for SPI master protocol drivers.  Some of the
2413  * other core methods are currently defined as inline functions.
2414  */
2415
2416 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2417 {
2418         if (master->bits_per_word_mask) {
2419                 /* Only 32 bits fit in the mask */
2420                 if (bits_per_word > 32)
2421                         return -EINVAL;
2422                 if (!(master->bits_per_word_mask &
2423                                 SPI_BPW_MASK(bits_per_word)))
2424                         return -EINVAL;
2425         }
2426
2427         return 0;
2428 }
2429
2430 /**
2431  * spi_setup - setup SPI mode and clock rate
2432  * @spi: the device whose settings are being modified
2433  * Context: can sleep, and no requests are queued to the device
2434  *
2435  * SPI protocol drivers may need to update the transfer mode if the
2436  * device doesn't work with its default.  They may likewise need
2437  * to update clock rates or word sizes from initial values.  This function
2438  * changes those settings, and must be called from a context that can sleep.
2439  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2440  * effect the next time the device is selected and data is transferred to
2441  * or from it.  When this function returns, the spi device is deselected.
2442  *
2443  * Note that this call will fail if the protocol driver specifies an option
2444  * that the underlying controller or its driver does not support.  For
2445  * example, not all hardware supports wire transfers using nine bit words,
2446  * LSB-first wire encoding, or active-high chipselects.
2447  *
2448  * Return: zero on success, else a negative error code.
2449  */
2450 int spi_setup(struct spi_device *spi)
2451 {
2452         unsigned        bad_bits, ugly_bits;
2453         int             status;
2454
2455         /* check mode to prevent that DUAL and QUAD set at the same time
2456          */
2457         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2458                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2459                 dev_err(&spi->dev,
2460                 "setup: can not select dual and quad at the same time\n");
2461                 return -EINVAL;
2462         }
2463         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2464          */
2465         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2466                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2467                 return -EINVAL;
2468         /* help drivers fail *cleanly* when they need options
2469          * that aren't supported with their current master
2470          */
2471         bad_bits = spi->mode & ~spi->master->mode_bits;
2472         ugly_bits = bad_bits &
2473                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2474         if (ugly_bits) {
2475                 dev_warn(&spi->dev,
2476                          "setup: ignoring unsupported mode bits %x\n",
2477                          ugly_bits);
2478                 spi->mode &= ~ugly_bits;
2479                 bad_bits &= ~ugly_bits;
2480         }
2481         if (bad_bits) {
2482                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2483                         bad_bits);
2484                 return -EINVAL;
2485         }
2486
2487         if (!spi->bits_per_word)
2488                 spi->bits_per_word = 8;
2489
2490         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2491         if (status)
2492                 return status;
2493
2494         if (!spi->max_speed_hz)
2495                 spi->max_speed_hz = spi->master->max_speed_hz;
2496
2497         if (spi->master->setup)
2498                 status = spi->master->setup(spi);
2499
2500         spi_set_cs(spi, false);
2501
2502         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2503                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2504                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2505                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2506                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2507                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2508                         spi->bits_per_word, spi->max_speed_hz,
2509                         status);
2510
2511         return status;
2512 }
2513 EXPORT_SYMBOL_GPL(spi_setup);
2514
2515 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2516 {
2517         struct spi_master *master = spi->master;
2518         struct spi_transfer *xfer;
2519         int w_size;
2520
2521         if (list_empty(&message->transfers))
2522                 return -EINVAL;
2523
2524         /* Half-duplex links include original MicroWire, and ones with
2525          * only one data pin like SPI_3WIRE (switches direction) or where
2526          * either MOSI or MISO is missing.  They can also be caused by
2527          * software limitations.
2528          */
2529         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2530                         || (spi->mode & SPI_3WIRE)) {
2531                 unsigned flags = master->flags;
2532
2533                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2534                         if (xfer->rx_buf && xfer->tx_buf)
2535                                 return -EINVAL;
2536                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2537                                 return -EINVAL;
2538                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2539                                 return -EINVAL;
2540                 }
2541         }
2542
2543         /**
2544          * Set transfer bits_per_word and max speed as spi device default if
2545          * it is not set for this transfer.
2546          * Set transfer tx_nbits and rx_nbits as single transfer default
2547          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2548          */
2549         message->frame_length = 0;
2550         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2551                 message->frame_length += xfer->len;
2552                 if (!xfer->bits_per_word)
2553                         xfer->bits_per_word = spi->bits_per_word;
2554
2555                 if (!xfer->speed_hz)
2556                         xfer->speed_hz = spi->max_speed_hz;
2557                 if (!xfer->speed_hz)
2558                         xfer->speed_hz = master->max_speed_hz;
2559
2560                 if (master->max_speed_hz &&
2561                     xfer->speed_hz > master->max_speed_hz)
2562                         xfer->speed_hz = master->max_speed_hz;
2563
2564                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2565                         return -EINVAL;
2566
2567                 /*
2568                  * SPI transfer length should be multiple of SPI word size
2569                  * where SPI word size should be power-of-two multiple
2570                  */
2571                 if (xfer->bits_per_word <= 8)
2572                         w_size = 1;
2573                 else if (xfer->bits_per_word <= 16)
2574                         w_size = 2;
2575                 else
2576                         w_size = 4;
2577
2578                 /* No partial transfers accepted */
2579                 if (xfer->len % w_size)
2580                         return -EINVAL;
2581
2582                 if (xfer->speed_hz && master->min_speed_hz &&
2583                     xfer->speed_hz < master->min_speed_hz)
2584                         return -EINVAL;
2585
2586                 if (xfer->tx_buf && !xfer->tx_nbits)
2587                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2588                 if (xfer->rx_buf && !xfer->rx_nbits)
2589                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2590                 /* check transfer tx/rx_nbits:
2591                  * 1. check the value matches one of single, dual and quad
2592                  * 2. check tx/rx_nbits match the mode in spi_device
2593                  */
2594                 if (xfer->tx_buf) {
2595                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2596                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2597                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2598                                 return -EINVAL;
2599                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2600                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2601                                 return -EINVAL;
2602                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2603                                 !(spi->mode & SPI_TX_QUAD))
2604                                 return -EINVAL;
2605                 }
2606                 /* check transfer rx_nbits */
2607                 if (xfer->rx_buf) {
2608                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2609                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2610                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2611                                 return -EINVAL;
2612                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2613                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2614                                 return -EINVAL;
2615                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2616                                 !(spi->mode & SPI_RX_QUAD))
2617                                 return -EINVAL;
2618                 }
2619         }
2620
2621         message->status = -EINPROGRESS;
2622
2623         return 0;
2624 }
2625
2626 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2627 {
2628         struct spi_master *master = spi->master;
2629
2630         message->spi = spi;
2631
2632         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2633         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2634
2635         trace_spi_message_submit(message);
2636
2637         return master->transfer(spi, message);
2638 }
2639
2640 /**
2641  * spi_async - asynchronous SPI transfer
2642  * @spi: device with which data will be exchanged
2643  * @message: describes the data transfers, including completion callback
2644  * Context: any (irqs may be blocked, etc)
2645  *
2646  * This call may be used in_irq and other contexts which can't sleep,
2647  * as well as from task contexts which can sleep.
2648  *
2649  * The completion callback is invoked in a context which can't sleep.
2650  * Before that invocation, the value of message->status is undefined.
2651  * When the callback is issued, message->status holds either zero (to
2652  * indicate complete success) or a negative error code.  After that
2653  * callback returns, the driver which issued the transfer request may
2654  * deallocate the associated memory; it's no longer in use by any SPI
2655  * core or controller driver code.
2656  *
2657  * Note that although all messages to a spi_device are handled in
2658  * FIFO order, messages may go to different devices in other orders.
2659  * Some device might be higher priority, or have various "hard" access
2660  * time requirements, for example.
2661  *
2662  * On detection of any fault during the transfer, processing of
2663  * the entire message is aborted, and the device is deselected.
2664  * Until returning from the associated message completion callback,
2665  * no other spi_message queued to that device will be processed.
2666  * (This rule applies equally to all the synchronous transfer calls,
2667  * which are wrappers around this core asynchronous primitive.)
2668  *
2669  * Return: zero on success, else a negative error code.
2670  */
2671 int spi_async(struct spi_device *spi, struct spi_message *message)
2672 {
2673         struct spi_master *master = spi->master;
2674         int ret;
2675         unsigned long flags;
2676
2677         ret = __spi_validate(spi, message);
2678         if (ret != 0)
2679                 return ret;
2680
2681         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2682
2683         if (master->bus_lock_flag)
2684                 ret = -EBUSY;
2685         else
2686                 ret = __spi_async(spi, message);
2687
2688         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2689
2690         return ret;
2691 }
2692 EXPORT_SYMBOL_GPL(spi_async);
2693
2694 /**
2695  * spi_async_locked - version of spi_async with exclusive bus usage
2696  * @spi: device with which data will be exchanged
2697  * @message: describes the data transfers, including completion callback
2698  * Context: any (irqs may be blocked, etc)
2699  *
2700  * This call may be used in_irq and other contexts which can't sleep,
2701  * as well as from task contexts which can sleep.
2702  *
2703  * The completion callback is invoked in a context which can't sleep.
2704  * Before that invocation, the value of message->status is undefined.
2705  * When the callback is issued, message->status holds either zero (to
2706  * indicate complete success) or a negative error code.  After that
2707  * callback returns, the driver which issued the transfer request may
2708  * deallocate the associated memory; it's no longer in use by any SPI
2709  * core or controller driver code.
2710  *
2711  * Note that although all messages to a spi_device are handled in
2712  * FIFO order, messages may go to different devices in other orders.
2713  * Some device might be higher priority, or have various "hard" access
2714  * time requirements, for example.
2715  *
2716  * On detection of any fault during the transfer, processing of
2717  * the entire message is aborted, and the device is deselected.
2718  * Until returning from the associated message completion callback,
2719  * no other spi_message queued to that device will be processed.
2720  * (This rule applies equally to all the synchronous transfer calls,
2721  * which are wrappers around this core asynchronous primitive.)
2722  *
2723  * Return: zero on success, else a negative error code.
2724  */
2725 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2726 {
2727         struct spi_master *master = spi->master;
2728         int ret;
2729         unsigned long flags;
2730
2731         ret = __spi_validate(spi, message);
2732         if (ret != 0)
2733                 return ret;
2734
2735         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2736
2737         ret = __spi_async(spi, message);
2738
2739         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2740
2741         return ret;
2742
2743 }
2744 EXPORT_SYMBOL_GPL(spi_async_locked);
2745
2746
2747 int spi_flash_read(struct spi_device *spi,
2748                    struct spi_flash_read_message *msg)
2749
2750 {
2751         struct spi_master *master = spi->master;
2752         struct device *rx_dev = NULL;
2753         int ret;
2754
2755         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2756              msg->addr_nbits == SPI_NBITS_DUAL) &&
2757             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2758                 return -EINVAL;
2759         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2760              msg->addr_nbits == SPI_NBITS_QUAD) &&
2761             !(spi->mode & SPI_TX_QUAD))
2762                 return -EINVAL;
2763         if (msg->data_nbits == SPI_NBITS_DUAL &&
2764             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2765                 return -EINVAL;
2766         if (msg->data_nbits == SPI_NBITS_QUAD &&
2767             !(spi->mode &  SPI_RX_QUAD))
2768                 return -EINVAL;
2769
2770         if (master->auto_runtime_pm) {
2771                 ret = pm_runtime_get_sync(master->dev.parent);
2772                 if (ret < 0) {
2773                         dev_err(&master->dev, "Failed to power device: %d\n",
2774                                 ret);
2775                         return ret;
2776                 }
2777         }
2778
2779         mutex_lock(&master->bus_lock_mutex);
2780         mutex_lock(&master->io_mutex);
2781         if (master->dma_rx) {
2782                 rx_dev = master->dma_rx->device->dev;
2783                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2784                                   msg->buf, msg->len,
2785                                   DMA_FROM_DEVICE);
2786                 if (!ret)
2787                         msg->cur_msg_mapped = true;
2788         }
2789         ret = master->spi_flash_read(spi, msg);
2790         if (msg->cur_msg_mapped)
2791                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2792                               DMA_FROM_DEVICE);
2793         mutex_unlock(&master->io_mutex);
2794         mutex_unlock(&master->bus_lock_mutex);
2795
2796         if (master->auto_runtime_pm)
2797                 pm_runtime_put(master->dev.parent);
2798
2799         return ret;
2800 }
2801 EXPORT_SYMBOL_GPL(spi_flash_read);
2802
2803 /*-------------------------------------------------------------------------*/
2804
2805 /* Utility methods for SPI master protocol drivers, layered on
2806  * top of the core.  Some other utility methods are defined as
2807  * inline functions.
2808  */
2809
2810 static void spi_complete(void *arg)
2811 {
2812         complete(arg);
2813 }
2814
2815 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2816 {
2817         DECLARE_COMPLETION_ONSTACK(done);
2818         int status;
2819         struct spi_master *master = spi->master;
2820         unsigned long flags;
2821
2822         status = __spi_validate(spi, message);
2823         if (status != 0)
2824                 return status;
2825
2826         message->complete = spi_complete;
2827         message->context = &done;
2828         message->spi = spi;
2829
2830         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2831         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2832
2833         /* If we're not using the legacy transfer method then we will
2834          * try to transfer in the calling context so special case.
2835          * This code would be less tricky if we could remove the
2836          * support for driver implemented message queues.
2837          */
2838         if (master->transfer == spi_queued_transfer) {
2839                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2840
2841                 trace_spi_message_submit(message);
2842
2843                 status = __spi_queued_transfer(spi, message, false);
2844
2845                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2846         } else {
2847                 status = spi_async_locked(spi, message);
2848         }
2849
2850         if (status == 0) {
2851                 /* Push out the messages in the calling context if we
2852                  * can.
2853                  */
2854                 if (master->transfer == spi_queued_transfer) {
2855                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2856                                                        spi_sync_immediate);
2857                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2858                                                        spi_sync_immediate);
2859                         __spi_pump_messages(master, false);
2860                 }
2861
2862                 wait_for_completion(&done);
2863                 status = message->status;
2864         }
2865         message->context = NULL;
2866         return status;
2867 }
2868
2869 /**
2870  * spi_sync - blocking/synchronous SPI data transfers
2871  * @spi: device with which data will be exchanged
2872  * @message: describes the data transfers
2873  * Context: can sleep
2874  *
2875  * This call may only be used from a context that may sleep.  The sleep
2876  * is non-interruptible, and has no timeout.  Low-overhead controller
2877  * drivers may DMA directly into and out of the message buffers.
2878  *
2879  * Note that the SPI device's chip select is active during the message,
2880  * and then is normally disabled between messages.  Drivers for some
2881  * frequently-used devices may want to minimize costs of selecting a chip,
2882  * by leaving it selected in anticipation that the next message will go
2883  * to the same chip.  (That may increase power usage.)
2884  *
2885  * Also, the caller is guaranteeing that the memory associated with the
2886  * message will not be freed before this call returns.
2887  *
2888  * Return: zero on success, else a negative error code.
2889  */
2890 int spi_sync(struct spi_device *spi, struct spi_message *message)
2891 {
2892         int ret;
2893
2894         mutex_lock(&spi->master->bus_lock_mutex);
2895         ret = __spi_sync(spi, message);
2896         mutex_unlock(&spi->master->bus_lock_mutex);
2897
2898         return ret;
2899 }
2900 EXPORT_SYMBOL_GPL(spi_sync);
2901
2902 /**
2903  * spi_sync_locked - version of spi_sync with exclusive bus usage
2904  * @spi: device with which data will be exchanged
2905  * @message: describes the data transfers
2906  * Context: can sleep
2907  *
2908  * This call may only be used from a context that may sleep.  The sleep
2909  * is non-interruptible, and has no timeout.  Low-overhead controller
2910  * drivers may DMA directly into and out of the message buffers.
2911  *
2912  * This call should be used by drivers that require exclusive access to the
2913  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2914  * be released by a spi_bus_unlock call when the exclusive access is over.
2915  *
2916  * Return: zero on success, else a negative error code.
2917  */
2918 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2919 {
2920         return __spi_sync(spi, message);
2921 }
2922 EXPORT_SYMBOL_GPL(spi_sync_locked);
2923
2924 /**
2925  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2926  * @master: SPI bus master that should be locked for exclusive bus access
2927  * Context: can sleep
2928  *
2929  * This call may only be used from a context that may sleep.  The sleep
2930  * is non-interruptible, and has no timeout.
2931  *
2932  * This call should be used by drivers that require exclusive access to the
2933  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2934  * exclusive access is over. Data transfer must be done by spi_sync_locked
2935  * and spi_async_locked calls when the SPI bus lock is held.
2936  *
2937  * Return: always zero.
2938  */
2939 int spi_bus_lock(struct spi_master *master)
2940 {
2941         unsigned long flags;
2942
2943         mutex_lock(&master->bus_lock_mutex);
2944
2945         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2946         master->bus_lock_flag = 1;
2947         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2948
2949         /* mutex remains locked until spi_bus_unlock is called */
2950
2951         return 0;
2952 }
2953 EXPORT_SYMBOL_GPL(spi_bus_lock);
2954
2955 /**
2956  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2957  * @master: SPI bus master that was locked for exclusive bus access
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.
2962  *
2963  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2964  * call.
2965  *
2966  * Return: always zero.
2967  */
2968 int spi_bus_unlock(struct spi_master *master)
2969 {
2970         master->bus_lock_flag = 0;
2971
2972         mutex_unlock(&master->bus_lock_mutex);
2973
2974         return 0;
2975 }
2976 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2977
2978 /* portable code must never pass more than 32 bytes */
2979 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2980
2981 static u8       *buf;
2982
2983 /**
2984  * spi_write_then_read - SPI synchronous write followed by read
2985  * @spi: device with which data will be exchanged
2986  * @txbuf: data to be written (need not be dma-safe)
2987  * @n_tx: size of txbuf, in bytes
2988  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2989  * @n_rx: size of rxbuf, in bytes
2990  * Context: can sleep
2991  *
2992  * This performs a half duplex MicroWire style transaction with the
2993  * device, sending txbuf and then reading rxbuf.  The return value
2994  * is zero for success, else a negative errno status code.
2995  * This call may only be used from a context that may sleep.
2996  *
2997  * Parameters to this routine are always copied using a small buffer;
2998  * portable code should never use this for more than 32 bytes.
2999  * Performance-sensitive or bulk transfer code should instead use
3000  * spi_{async,sync}() calls with dma-safe buffers.
3001  *
3002  * Return: zero on success, else a negative error code.
3003  */
3004 int spi_write_then_read(struct spi_device *spi,
3005                 const void *txbuf, unsigned n_tx,
3006                 void *rxbuf, unsigned n_rx)
3007 {
3008         static DEFINE_MUTEX(lock);
3009
3010         int                     status;
3011         struct spi_message      message;
3012         struct spi_transfer     x[2];
3013         u8                      *local_buf;
3014
3015         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3016          * copying here, (as a pure convenience thing), but we can
3017          * keep heap costs out of the hot path unless someone else is
3018          * using the pre-allocated buffer or the transfer is too large.
3019          */
3020         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3021                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3022                                     GFP_KERNEL | GFP_DMA);
3023                 if (!local_buf)
3024                         return -ENOMEM;
3025         } else {
3026                 local_buf = buf;
3027         }
3028
3029         spi_message_init(&message);
3030         memset(x, 0, sizeof(x));
3031         if (n_tx) {
3032                 x[0].len = n_tx;
3033                 spi_message_add_tail(&x[0], &message);
3034         }
3035         if (n_rx) {
3036                 x[1].len = n_rx;
3037                 spi_message_add_tail(&x[1], &message);
3038         }
3039
3040         memcpy(local_buf, txbuf, n_tx);
3041         x[0].tx_buf = local_buf;
3042         x[1].rx_buf = local_buf + n_tx;
3043
3044         /* do the i/o */
3045         status = spi_sync(spi, &message);
3046         if (status == 0)
3047                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3048
3049         if (x[0].tx_buf == buf)
3050                 mutex_unlock(&lock);
3051         else
3052                 kfree(local_buf);
3053
3054         return status;
3055 }
3056 EXPORT_SYMBOL_GPL(spi_write_then_read);
3057
3058 /*-------------------------------------------------------------------------*/
3059
3060 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3061 static int __spi_of_device_match(struct device *dev, void *data)
3062 {
3063         return dev->of_node == data;
3064 }
3065
3066 /* must call put_device() when done with returned spi_device device */
3067 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3068 {
3069         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3070                                                 __spi_of_device_match);
3071         return dev ? to_spi_device(dev) : NULL;
3072 }
3073
3074 static int __spi_of_master_match(struct device *dev, const void *data)
3075 {
3076         return dev->of_node == data;
3077 }
3078
3079 /* the spi masters are not using spi_bus, so we find it with another way */
3080 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3081 {
3082         struct device *dev;
3083
3084         dev = class_find_device(&spi_master_class, NULL, node,
3085                                 __spi_of_master_match);
3086         if (!dev)
3087                 return NULL;
3088
3089         /* reference got in class_find_device */
3090         return container_of(dev, struct spi_master, dev);
3091 }
3092
3093 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3094                          void *arg)
3095 {
3096         struct of_reconfig_data *rd = arg;
3097         struct spi_master *master;
3098         struct spi_device *spi;
3099
3100         switch (of_reconfig_get_state_change(action, arg)) {
3101         case OF_RECONFIG_CHANGE_ADD:
3102                 master = of_find_spi_master_by_node(rd->dn->parent);
3103                 if (master == NULL)
3104                         return NOTIFY_OK;       /* not for us */
3105
3106                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3107                         put_device(&master->dev);
3108                         return NOTIFY_OK;
3109                 }
3110
3111                 spi = of_register_spi_device(master, rd->dn);
3112                 put_device(&master->dev);
3113
3114                 if (IS_ERR(spi)) {
3115                         pr_err("%s: failed to create for '%s'\n",
3116                                         __func__, rd->dn->full_name);
3117                         return notifier_from_errno(PTR_ERR(spi));
3118                 }
3119                 break;
3120
3121         case OF_RECONFIG_CHANGE_REMOVE:
3122                 /* already depopulated? */
3123                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3124                         return NOTIFY_OK;
3125
3126                 /* find our device by node */
3127                 spi = of_find_spi_device_by_node(rd->dn);
3128                 if (spi == NULL)
3129                         return NOTIFY_OK;       /* no? not meant for us */
3130
3131                 /* unregister takes one ref away */
3132                 spi_unregister_device(spi);
3133
3134                 /* and put the reference of the find */
3135                 put_device(&spi->dev);
3136                 break;
3137         }
3138
3139         return NOTIFY_OK;
3140 }
3141
3142 static struct notifier_block spi_of_notifier = {
3143         .notifier_call = of_spi_notify,
3144 };
3145 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3146 extern struct notifier_block spi_of_notifier;
3147 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3148
3149 #if IS_ENABLED(CONFIG_ACPI)
3150 static int spi_acpi_master_match(struct device *dev, const void *data)
3151 {
3152         return ACPI_COMPANION(dev->parent) == data;
3153 }
3154
3155 static int spi_acpi_device_match(struct device *dev, void *data)
3156 {
3157         return ACPI_COMPANION(dev) == data;
3158 }
3159
3160 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3161 {
3162         struct device *dev;
3163
3164         dev = class_find_device(&spi_master_class, NULL, adev,
3165                                 spi_acpi_master_match);
3166         if (!dev)
3167                 return NULL;
3168
3169         return container_of(dev, struct spi_master, dev);
3170 }
3171
3172 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3173 {
3174         struct device *dev;
3175
3176         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3177
3178         return dev ? to_spi_device(dev) : NULL;
3179 }
3180
3181 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3182                            void *arg)
3183 {
3184         struct acpi_device *adev = arg;
3185         struct spi_master *master;
3186         struct spi_device *spi;
3187
3188         switch (value) {
3189         case ACPI_RECONFIG_DEVICE_ADD:
3190                 master = acpi_spi_find_master_by_adev(adev->parent);
3191                 if (!master)
3192                         break;
3193
3194                 acpi_register_spi_device(master, adev);
3195                 put_device(&master->dev);
3196                 break;
3197         case ACPI_RECONFIG_DEVICE_REMOVE:
3198                 if (!acpi_device_enumerated(adev))
3199                         break;
3200
3201                 spi = acpi_spi_find_device_by_adev(adev);
3202                 if (!spi)
3203                         break;
3204
3205                 spi_unregister_device(spi);
3206                 put_device(&spi->dev);
3207                 break;
3208         }
3209
3210         return NOTIFY_OK;
3211 }
3212
3213 static struct notifier_block spi_acpi_notifier = {
3214         .notifier_call = acpi_spi_notify,
3215 };
3216 #else
3217 extern struct notifier_block spi_acpi_notifier;
3218 #endif
3219
3220 static int __init spi_init(void)
3221 {
3222         int     status;
3223
3224         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3225         if (!buf) {
3226                 status = -ENOMEM;
3227                 goto err0;
3228         }
3229
3230         status = bus_register(&spi_bus_type);
3231         if (status < 0)
3232                 goto err1;
3233
3234         status = class_register(&spi_master_class);
3235         if (status < 0)
3236                 goto err2;
3237
3238         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3239                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3240         if (IS_ENABLED(CONFIG_ACPI))
3241                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3242
3243         return 0;
3244
3245 err2:
3246         bus_unregister(&spi_bus_type);
3247 err1:
3248         kfree(buf);
3249         buf = NULL;
3250 err0:
3251         return status;
3252 }
3253
3254 /* board_info is normally registered in arch_initcall(),
3255  * but even essential drivers wait till later
3256  *
3257  * REVISIT only boardinfo really needs static linking. the rest (device and
3258  * driver registration) _could_ be dynamically linked (modular) ... costs
3259  * include needing to have boardinfo data structures be much more public.
3260  */
3261 postcore_initcall(spi_init);
3262