Merge branches 'acpi-pci' and 'pm-pci'
[firefly-linux-kernel-4.4.55.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 = container_of(dev,                      \
88                                               struct spi_device, dev);  \
89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
90 }                                                                       \
91 static struct device_attribute dev_attr_spi_device_##field = {          \
92         .attr = { .name = file, .mode = S_IRUGO },                      \
93         .show = spi_device_##field##_show,                              \
94 }
95
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
98                                             char *buf)                  \
99 {                                                                       \
100         unsigned long flags;                                            \
101         ssize_t len;                                                    \
102         spin_lock_irqsave(&stat->lock, flags);                          \
103         len = sprintf(buf, format_string, stat->field);                 \
104         spin_unlock_irqrestore(&stat->lock, flags);                     \
105         return len;                                                     \
106 }                                                                       \
107 SPI_STATISTICS_ATTRS(name, file)
108
109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
111                                  field, format_string)
112
113 SPI_STATISTICS_SHOW(messages, "%lu");
114 SPI_STATISTICS_SHOW(transfers, "%lu");
115 SPI_STATISTICS_SHOW(errors, "%lu");
116 SPI_STATISTICS_SHOW(timedout, "%lu");
117
118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120 SPI_STATISTICS_SHOW(spi_async, "%lu");
121
122 SPI_STATISTICS_SHOW(bytes, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125
126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
128                                  "transfer_bytes_histo_" number,        \
129                                  transfer_bytes_histo[index],  "%lu")
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147
148 static struct attribute *spi_dev_attrs[] = {
149         &dev_attr_modalias.attr,
150         NULL,
151 };
152
153 static const struct attribute_group spi_dev_group = {
154         .attrs  = spi_dev_attrs,
155 };
156
157 static struct attribute *spi_device_statistics_attrs[] = {
158         &dev_attr_spi_device_messages.attr,
159         &dev_attr_spi_device_transfers.attr,
160         &dev_attr_spi_device_errors.attr,
161         &dev_attr_spi_device_timedout.attr,
162         &dev_attr_spi_device_spi_sync.attr,
163         &dev_attr_spi_device_spi_sync_immediate.attr,
164         &dev_attr_spi_device_spi_async.attr,
165         &dev_attr_spi_device_bytes.attr,
166         &dev_attr_spi_device_bytes_rx.attr,
167         &dev_attr_spi_device_bytes_tx.attr,
168         &dev_attr_spi_device_transfer_bytes_histo0.attr,
169         &dev_attr_spi_device_transfer_bytes_histo1.attr,
170         &dev_attr_spi_device_transfer_bytes_histo2.attr,
171         &dev_attr_spi_device_transfer_bytes_histo3.attr,
172         &dev_attr_spi_device_transfer_bytes_histo4.attr,
173         &dev_attr_spi_device_transfer_bytes_histo5.attr,
174         &dev_attr_spi_device_transfer_bytes_histo6.attr,
175         &dev_attr_spi_device_transfer_bytes_histo7.attr,
176         &dev_attr_spi_device_transfer_bytes_histo8.attr,
177         &dev_attr_spi_device_transfer_bytes_histo9.attr,
178         &dev_attr_spi_device_transfer_bytes_histo10.attr,
179         &dev_attr_spi_device_transfer_bytes_histo11.attr,
180         &dev_attr_spi_device_transfer_bytes_histo12.attr,
181         &dev_attr_spi_device_transfer_bytes_histo13.attr,
182         &dev_attr_spi_device_transfer_bytes_histo14.attr,
183         &dev_attr_spi_device_transfer_bytes_histo15.attr,
184         &dev_attr_spi_device_transfer_bytes_histo16.attr,
185         NULL,
186 };
187
188 static const struct attribute_group spi_device_statistics_group = {
189         .name  = "statistics",
190         .attrs  = spi_device_statistics_attrs,
191 };
192
193 static const struct attribute_group *spi_dev_groups[] = {
194         &spi_dev_group,
195         &spi_device_statistics_group,
196         NULL,
197 };
198
199 static struct attribute *spi_master_statistics_attrs[] = {
200         &dev_attr_spi_master_messages.attr,
201         &dev_attr_spi_master_transfers.attr,
202         &dev_attr_spi_master_errors.attr,
203         &dev_attr_spi_master_timedout.attr,
204         &dev_attr_spi_master_spi_sync.attr,
205         &dev_attr_spi_master_spi_sync_immediate.attr,
206         &dev_attr_spi_master_spi_async.attr,
207         &dev_attr_spi_master_bytes.attr,
208         &dev_attr_spi_master_bytes_rx.attr,
209         &dev_attr_spi_master_bytes_tx.attr,
210         &dev_attr_spi_master_transfer_bytes_histo0.attr,
211         &dev_attr_spi_master_transfer_bytes_histo1.attr,
212         &dev_attr_spi_master_transfer_bytes_histo2.attr,
213         &dev_attr_spi_master_transfer_bytes_histo3.attr,
214         &dev_attr_spi_master_transfer_bytes_histo4.attr,
215         &dev_attr_spi_master_transfer_bytes_histo5.attr,
216         &dev_attr_spi_master_transfer_bytes_histo6.attr,
217         &dev_attr_spi_master_transfer_bytes_histo7.attr,
218         &dev_attr_spi_master_transfer_bytes_histo8.attr,
219         &dev_attr_spi_master_transfer_bytes_histo9.attr,
220         &dev_attr_spi_master_transfer_bytes_histo10.attr,
221         &dev_attr_spi_master_transfer_bytes_histo11.attr,
222         &dev_attr_spi_master_transfer_bytes_histo12.attr,
223         &dev_attr_spi_master_transfer_bytes_histo13.attr,
224         &dev_attr_spi_master_transfer_bytes_histo14.attr,
225         &dev_attr_spi_master_transfer_bytes_histo15.attr,
226         &dev_attr_spi_master_transfer_bytes_histo16.attr,
227         NULL,
228 };
229
230 static const struct attribute_group spi_master_statistics_group = {
231         .name  = "statistics",
232         .attrs  = spi_master_statistics_attrs,
233 };
234
235 static const struct attribute_group *spi_master_groups[] = {
236         &spi_master_statistics_group,
237         NULL,
238 };
239
240 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
241                                        struct spi_transfer *xfer,
242                                        struct spi_master *master)
243 {
244         unsigned long flags;
245         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
246
247         if (l2len < 0)
248                 l2len = 0;
249
250         spin_lock_irqsave(&stats->lock, flags);
251
252         stats->transfers++;
253         stats->transfer_bytes_histo[l2len]++;
254
255         stats->bytes += xfer->len;
256         if ((xfer->tx_buf) &&
257             (xfer->tx_buf != master->dummy_tx))
258                 stats->bytes_tx += xfer->len;
259         if ((xfer->rx_buf) &&
260             (xfer->rx_buf != master->dummy_rx))
261                 stats->bytes_rx += xfer->len;
262
263         spin_unlock_irqrestore(&stats->lock, flags);
264 }
265 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
266
267 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
268  * and the sysfs version makes coldplug work too.
269  */
270
271 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
272                                                 const struct spi_device *sdev)
273 {
274         while (id->name[0]) {
275                 if (!strcmp(sdev->modalias, id->name))
276                         return id;
277                 id++;
278         }
279         return NULL;
280 }
281
282 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
283 {
284         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
285
286         return spi_match_id(sdrv->id_table, sdev);
287 }
288 EXPORT_SYMBOL_GPL(spi_get_device_id);
289
290 static int spi_match_device(struct device *dev, struct device_driver *drv)
291 {
292         const struct spi_device *spi = to_spi_device(dev);
293         const struct spi_driver *sdrv = to_spi_driver(drv);
294
295         /* Attempt an OF style match */
296         if (of_driver_match_device(dev, drv))
297                 return 1;
298
299         /* Then try ACPI */
300         if (acpi_driver_match_device(dev, drv))
301                 return 1;
302
303         if (sdrv->id_table)
304                 return !!spi_match_id(sdrv->id_table, spi);
305
306         return strcmp(spi->modalias, drv->name) == 0;
307 }
308
309 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
310 {
311         const struct spi_device         *spi = to_spi_device(dev);
312         int rc;
313
314         rc = acpi_device_uevent_modalias(dev, env);
315         if (rc != -ENODEV)
316                 return rc;
317
318         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
319         return 0;
320 }
321
322 struct bus_type spi_bus_type = {
323         .name           = "spi",
324         .dev_groups     = spi_dev_groups,
325         .match          = spi_match_device,
326         .uevent         = spi_uevent,
327 };
328 EXPORT_SYMBOL_GPL(spi_bus_type);
329
330
331 static int spi_drv_probe(struct device *dev)
332 {
333         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
334         struct spi_device               *spi = to_spi_device(dev);
335         int ret;
336
337         ret = of_clk_set_defaults(dev->of_node, false);
338         if (ret)
339                 return ret;
340
341         if (dev->of_node) {
342                 spi->irq = of_irq_get(dev->of_node, 0);
343                 if (spi->irq == -EPROBE_DEFER)
344                         return -EPROBE_DEFER;
345                 if (spi->irq < 0)
346                         spi->irq = 0;
347         }
348
349         ret = dev_pm_domain_attach(dev, true);
350         if (ret != -EPROBE_DEFER) {
351                 ret = sdrv->probe(spi);
352                 if (ret)
353                         dev_pm_domain_detach(dev, true);
354         }
355
356         return ret;
357 }
358
359 static int spi_drv_remove(struct device *dev)
360 {
361         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
362         int ret;
363
364         ret = sdrv->remove(to_spi_device(dev));
365         dev_pm_domain_detach(dev, true);
366
367         return ret;
368 }
369
370 static void spi_drv_shutdown(struct device *dev)
371 {
372         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
373
374         sdrv->shutdown(to_spi_device(dev));
375 }
376
377 /**
378  * __spi_register_driver - register a SPI driver
379  * @sdrv: the driver to register
380  * Context: can sleep
381  *
382  * Return: zero on success, else a negative error code.
383  */
384 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
385 {
386         sdrv->driver.owner = owner;
387         sdrv->driver.bus = &spi_bus_type;
388         if (sdrv->probe)
389                 sdrv->driver.probe = spi_drv_probe;
390         if (sdrv->remove)
391                 sdrv->driver.remove = spi_drv_remove;
392         if (sdrv->shutdown)
393                 sdrv->driver.shutdown = spi_drv_shutdown;
394         return driver_register(&sdrv->driver);
395 }
396 EXPORT_SYMBOL_GPL(__spi_register_driver);
397
398 /*-------------------------------------------------------------------------*/
399
400 /* SPI devices should normally not be created by SPI device drivers; that
401  * would make them board-specific.  Similarly with SPI master drivers.
402  * Device registration normally goes into like arch/.../mach.../board-YYY.c
403  * with other readonly (flashable) information about mainboard devices.
404  */
405
406 struct boardinfo {
407         struct list_head        list;
408         struct spi_board_info   board_info;
409 };
410
411 static LIST_HEAD(board_list);
412 static LIST_HEAD(spi_master_list);
413
414 /*
415  * Used to protect add/del opertion for board_info list and
416  * spi_master list, and their matching process
417  */
418 static DEFINE_MUTEX(board_lock);
419
420 /**
421  * spi_alloc_device - Allocate a new SPI device
422  * @master: Controller to which device is connected
423  * Context: can sleep
424  *
425  * Allows a driver to allocate and initialize a spi_device without
426  * registering it immediately.  This allows a driver to directly
427  * fill the spi_device with device parameters before calling
428  * spi_add_device() on it.
429  *
430  * Caller is responsible to call spi_add_device() on the returned
431  * spi_device structure to add it to the SPI master.  If the caller
432  * needs to discard the spi_device without adding it, then it should
433  * call spi_dev_put() on it.
434  *
435  * Return: a pointer to the new device, or NULL.
436  */
437 struct spi_device *spi_alloc_device(struct spi_master *master)
438 {
439         struct spi_device       *spi;
440
441         if (!spi_master_get(master))
442                 return NULL;
443
444         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
445         if (!spi) {
446                 spi_master_put(master);
447                 return NULL;
448         }
449
450         spi->master = master;
451         spi->dev.parent = &master->dev;
452         spi->dev.bus = &spi_bus_type;
453         spi->dev.release = spidev_release;
454         spi->cs_gpio = -ENOENT;
455
456         spin_lock_init(&spi->statistics.lock);
457
458         device_initialize(&spi->dev);
459         return spi;
460 }
461 EXPORT_SYMBOL_GPL(spi_alloc_device);
462
463 static void spi_dev_set_name(struct spi_device *spi)
464 {
465         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
466
467         if (adev) {
468                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
469                 return;
470         }
471
472         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
473                      spi->chip_select);
474 }
475
476 static int spi_dev_check(struct device *dev, void *data)
477 {
478         struct spi_device *spi = to_spi_device(dev);
479         struct spi_device *new_spi = data;
480
481         if (spi->master == new_spi->master &&
482             spi->chip_select == new_spi->chip_select)
483                 return -EBUSY;
484         return 0;
485 }
486
487 /**
488  * spi_add_device - Add spi_device allocated with spi_alloc_device
489  * @spi: spi_device to register
490  *
491  * Companion function to spi_alloc_device.  Devices allocated with
492  * spi_alloc_device can be added onto the spi bus with this function.
493  *
494  * Return: 0 on success; negative errno on failure
495  */
496 int spi_add_device(struct spi_device *spi)
497 {
498         static DEFINE_MUTEX(spi_add_lock);
499         struct spi_master *master = spi->master;
500         struct device *dev = master->dev.parent;
501         int status;
502
503         /* Chipselects are numbered 0..max; validate. */
504         if (spi->chip_select >= master->num_chipselect) {
505                 dev_err(dev, "cs%d >= max %d\n",
506                         spi->chip_select,
507                         master->num_chipselect);
508                 return -EINVAL;
509         }
510
511         /* Set the bus ID string */
512         spi_dev_set_name(spi);
513
514         /* We need to make sure there's no other device with this
515          * chipselect **BEFORE** we call setup(), else we'll trash
516          * its configuration.  Lock against concurrent add() calls.
517          */
518         mutex_lock(&spi_add_lock);
519
520         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
521         if (status) {
522                 dev_err(dev, "chipselect %d already in use\n",
523                                 spi->chip_select);
524                 goto done;
525         }
526
527         if (master->cs_gpios)
528                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
529
530         /* Drivers may modify this initial i/o setup, but will
531          * normally rely on the device being setup.  Devices
532          * using SPI_CS_HIGH can't coexist well otherwise...
533          */
534         status = spi_setup(spi);
535         if (status < 0) {
536                 dev_err(dev, "can't setup %s, status %d\n",
537                                 dev_name(&spi->dev), status);
538                 goto done;
539         }
540
541         /* Device may be bound to an active driver when this returns */
542         status = device_add(&spi->dev);
543         if (status < 0)
544                 dev_err(dev, "can't add %s, status %d\n",
545                                 dev_name(&spi->dev), status);
546         else
547                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
548
549 done:
550         mutex_unlock(&spi_add_lock);
551         return status;
552 }
553 EXPORT_SYMBOL_GPL(spi_add_device);
554
555 /**
556  * spi_new_device - instantiate one new SPI device
557  * @master: Controller to which device is connected
558  * @chip: Describes the SPI device
559  * Context: can sleep
560  *
561  * On typical mainboards, this is purely internal; and it's not needed
562  * after board init creates the hard-wired devices.  Some development
563  * platforms may not be able to use spi_register_board_info though, and
564  * this is exported so that for example a USB or parport based adapter
565  * driver could add devices (which it would learn about out-of-band).
566  *
567  * Return: the new device, or NULL.
568  */
569 struct spi_device *spi_new_device(struct spi_master *master,
570                                   struct spi_board_info *chip)
571 {
572         struct spi_device       *proxy;
573         int                     status;
574
575         /* NOTE:  caller did any chip->bus_num checks necessary.
576          *
577          * Also, unless we change the return value convention to use
578          * error-or-pointer (not NULL-or-pointer), troubleshootability
579          * suggests syslogged diagnostics are best here (ugh).
580          */
581
582         proxy = spi_alloc_device(master);
583         if (!proxy)
584                 return NULL;
585
586         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
587
588         proxy->chip_select = chip->chip_select;
589         proxy->max_speed_hz = chip->max_speed_hz;
590         proxy->mode = chip->mode;
591         proxy->irq = chip->irq;
592         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
593         proxy->dev.platform_data = (void *) chip->platform_data;
594         proxy->controller_data = chip->controller_data;
595         proxy->controller_state = NULL;
596
597         status = spi_add_device(proxy);
598         if (status < 0) {
599                 spi_dev_put(proxy);
600                 return NULL;
601         }
602
603         return proxy;
604 }
605 EXPORT_SYMBOL_GPL(spi_new_device);
606
607 static void spi_match_master_to_boardinfo(struct spi_master *master,
608                                 struct spi_board_info *bi)
609 {
610         struct spi_device *dev;
611
612         if (master->bus_num != bi->bus_num)
613                 return;
614
615         dev = spi_new_device(master, bi);
616         if (!dev)
617                 dev_err(master->dev.parent, "can't create new device for %s\n",
618                         bi->modalias);
619 }
620
621 /**
622  * spi_register_board_info - register SPI devices for a given board
623  * @info: array of chip descriptors
624  * @n: how many descriptors are provided
625  * Context: can sleep
626  *
627  * Board-specific early init code calls this (probably during arch_initcall)
628  * with segments of the SPI device table.  Any device nodes are created later,
629  * after the relevant parent SPI controller (bus_num) is defined.  We keep
630  * this table of devices forever, so that reloading a controller driver will
631  * not make Linux forget about these hard-wired devices.
632  *
633  * Other code can also call this, e.g. a particular add-on board might provide
634  * SPI devices through its expansion connector, so code initializing that board
635  * would naturally declare its SPI devices.
636  *
637  * The board info passed can safely be __initdata ... but be careful of
638  * any embedded pointers (platform_data, etc), they're copied as-is.
639  *
640  * Return: zero on success, else a negative error code.
641  */
642 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
643 {
644         struct boardinfo *bi;
645         int i;
646
647         if (!n)
648                 return -EINVAL;
649
650         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
651         if (!bi)
652                 return -ENOMEM;
653
654         for (i = 0; i < n; i++, bi++, info++) {
655                 struct spi_master *master;
656
657                 memcpy(&bi->board_info, info, sizeof(*info));
658                 mutex_lock(&board_lock);
659                 list_add_tail(&bi->list, &board_list);
660                 list_for_each_entry(master, &spi_master_list, list)
661                         spi_match_master_to_boardinfo(master, &bi->board_info);
662                 mutex_unlock(&board_lock);
663         }
664
665         return 0;
666 }
667
668 /*-------------------------------------------------------------------------*/
669
670 static void spi_set_cs(struct spi_device *spi, bool enable)
671 {
672         if (spi->mode & SPI_CS_HIGH)
673                 enable = !enable;
674
675         if (gpio_is_valid(spi->cs_gpio))
676                 gpio_set_value(spi->cs_gpio, !enable);
677         else if (spi->master->set_cs)
678                 spi->master->set_cs(spi, !enable);
679 }
680
681 #ifdef CONFIG_HAS_DMA
682 static int spi_map_buf(struct spi_master *master, struct device *dev,
683                        struct sg_table *sgt, void *buf, size_t len,
684                        enum dma_data_direction dir)
685 {
686         const bool vmalloced_buf = is_vmalloc_addr(buf);
687         int desc_len;
688         int sgs;
689         struct page *vm_page;
690         void *sg_buf;
691         size_t min;
692         int i, ret;
693
694         if (vmalloced_buf) {
695                 desc_len = PAGE_SIZE;
696                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
697         } else {
698                 desc_len = master->max_dma_len;
699                 sgs = DIV_ROUND_UP(len, desc_len);
700         }
701
702         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
703         if (ret != 0)
704                 return ret;
705
706         for (i = 0; i < sgs; i++) {
707
708                 if (vmalloced_buf) {
709                         min = min_t(size_t,
710                                     len, desc_len - offset_in_page(buf));
711                         vm_page = vmalloc_to_page(buf);
712                         if (!vm_page) {
713                                 sg_free_table(sgt);
714                                 return -ENOMEM;
715                         }
716                         sg_set_page(&sgt->sgl[i], vm_page,
717                                     min, offset_in_page(buf));
718                 } else {
719                         min = min_t(size_t, len, desc_len);
720                         sg_buf = buf;
721                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
722                 }
723
724
725                 buf += min;
726                 len -= min;
727         }
728
729         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
730         if (!ret)
731                 ret = -ENOMEM;
732         if (ret < 0) {
733                 sg_free_table(sgt);
734                 return ret;
735         }
736
737         sgt->nents = ret;
738
739         return 0;
740 }
741
742 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
743                           struct sg_table *sgt, enum dma_data_direction dir)
744 {
745         if (sgt->orig_nents) {
746                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
747                 sg_free_table(sgt);
748         }
749 }
750
751 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
752 {
753         struct device *tx_dev, *rx_dev;
754         struct spi_transfer *xfer;
755         int ret;
756
757         if (!master->can_dma)
758                 return 0;
759
760         if (master->dma_tx)
761                 tx_dev = master->dma_tx->device->dev;
762         else
763                 tx_dev = &master->dev;
764
765         if (master->dma_rx)
766                 rx_dev = master->dma_rx->device->dev;
767         else
768                 rx_dev = &master->dev;
769
770         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
771                 if (!master->can_dma(master, msg->spi, xfer))
772                         continue;
773
774                 if (xfer->tx_buf != NULL) {
775                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
776                                           (void *)xfer->tx_buf, xfer->len,
777                                           DMA_TO_DEVICE);
778                         if (ret != 0)
779                                 return ret;
780                 }
781
782                 if (xfer->rx_buf != NULL) {
783                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
784                                           xfer->rx_buf, xfer->len,
785                                           DMA_FROM_DEVICE);
786                         if (ret != 0) {
787                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
788                                               DMA_TO_DEVICE);
789                                 return ret;
790                         }
791                 }
792         }
793
794         master->cur_msg_mapped = true;
795
796         return 0;
797 }
798
799 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
800 {
801         struct spi_transfer *xfer;
802         struct device *tx_dev, *rx_dev;
803
804         if (!master->cur_msg_mapped || !master->can_dma)
805                 return 0;
806
807         if (master->dma_tx)
808                 tx_dev = master->dma_tx->device->dev;
809         else
810                 tx_dev = &master->dev;
811
812         if (master->dma_rx)
813                 rx_dev = master->dma_rx->device->dev;
814         else
815                 rx_dev = &master->dev;
816
817         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
818                 if (!master->can_dma(master, msg->spi, xfer))
819                         continue;
820
821                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
822                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
823         }
824
825         return 0;
826 }
827 #else /* !CONFIG_HAS_DMA */
828 static inline int __spi_map_msg(struct spi_master *master,
829                                 struct spi_message *msg)
830 {
831         return 0;
832 }
833
834 static inline int __spi_unmap_msg(struct spi_master *master,
835                                   struct spi_message *msg)
836 {
837         return 0;
838 }
839 #endif /* !CONFIG_HAS_DMA */
840
841 static inline int spi_unmap_msg(struct spi_master *master,
842                                 struct spi_message *msg)
843 {
844         struct spi_transfer *xfer;
845
846         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
847                 /*
848                  * Restore the original value of tx_buf or rx_buf if they are
849                  * NULL.
850                  */
851                 if (xfer->tx_buf == master->dummy_tx)
852                         xfer->tx_buf = NULL;
853                 if (xfer->rx_buf == master->dummy_rx)
854                         xfer->rx_buf = NULL;
855         }
856
857         return __spi_unmap_msg(master, msg);
858 }
859
860 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
861 {
862         struct spi_transfer *xfer;
863         void *tmp;
864         unsigned int max_tx, max_rx;
865
866         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
867                 max_tx = 0;
868                 max_rx = 0;
869
870                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
871                         if ((master->flags & SPI_MASTER_MUST_TX) &&
872                             !xfer->tx_buf)
873                                 max_tx = max(xfer->len, max_tx);
874                         if ((master->flags & SPI_MASTER_MUST_RX) &&
875                             !xfer->rx_buf)
876                                 max_rx = max(xfer->len, max_rx);
877                 }
878
879                 if (max_tx) {
880                         tmp = krealloc(master->dummy_tx, max_tx,
881                                        GFP_KERNEL | GFP_DMA);
882                         if (!tmp)
883                                 return -ENOMEM;
884                         master->dummy_tx = tmp;
885                         memset(tmp, 0, max_tx);
886                 }
887
888                 if (max_rx) {
889                         tmp = krealloc(master->dummy_rx, max_rx,
890                                        GFP_KERNEL | GFP_DMA);
891                         if (!tmp)
892                                 return -ENOMEM;
893                         master->dummy_rx = tmp;
894                 }
895
896                 if (max_tx || max_rx) {
897                         list_for_each_entry(xfer, &msg->transfers,
898                                             transfer_list) {
899                                 if (!xfer->tx_buf)
900                                         xfer->tx_buf = master->dummy_tx;
901                                 if (!xfer->rx_buf)
902                                         xfer->rx_buf = master->dummy_rx;
903                         }
904                 }
905         }
906
907         return __spi_map_msg(master, msg);
908 }
909
910 /*
911  * spi_transfer_one_message - Default implementation of transfer_one_message()
912  *
913  * This is a standard implementation of transfer_one_message() for
914  * drivers which impelment a transfer_one() operation.  It provides
915  * standard handling of delays and chip select management.
916  */
917 static int spi_transfer_one_message(struct spi_master *master,
918                                     struct spi_message *msg)
919 {
920         struct spi_transfer *xfer;
921         bool keep_cs = false;
922         int ret = 0;
923         unsigned long ms = 1;
924         struct spi_statistics *statm = &master->statistics;
925         struct spi_statistics *stats = &msg->spi->statistics;
926
927         spi_set_cs(msg->spi, true);
928
929         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
930         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
931
932         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
933                 trace_spi_transfer_start(msg, xfer);
934
935                 spi_statistics_add_transfer_stats(statm, xfer, master);
936                 spi_statistics_add_transfer_stats(stats, xfer, master);
937
938                 if (xfer->tx_buf || xfer->rx_buf) {
939                         reinit_completion(&master->xfer_completion);
940
941                         ret = master->transfer_one(master, msg->spi, xfer);
942                         if (ret < 0) {
943                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
944                                                                errors);
945                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
946                                                                errors);
947                                 dev_err(&msg->spi->dev,
948                                         "SPI transfer failed: %d\n", ret);
949                                 goto out;
950                         }
951
952                         if (ret > 0) {
953                                 ret = 0;
954                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
955                                 ms += ms + 100; /* some tolerance */
956
957                                 ms = wait_for_completion_timeout(&master->xfer_completion,
958                                                                  msecs_to_jiffies(ms));
959                         }
960
961                         if (ms == 0) {
962                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
963                                                                timedout);
964                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
965                                                                timedout);
966                                 dev_err(&msg->spi->dev,
967                                         "SPI transfer timed out\n");
968                                 msg->status = -ETIMEDOUT;
969                         }
970                 } else {
971                         if (xfer->len)
972                                 dev_err(&msg->spi->dev,
973                                         "Bufferless transfer has length %u\n",
974                                         xfer->len);
975                 }
976
977                 trace_spi_transfer_stop(msg, xfer);
978
979                 if (msg->status != -EINPROGRESS)
980                         goto out;
981
982                 if (xfer->delay_usecs)
983                         udelay(xfer->delay_usecs);
984
985                 if (xfer->cs_change) {
986                         if (list_is_last(&xfer->transfer_list,
987                                          &msg->transfers)) {
988                                 keep_cs = true;
989                         } else {
990                                 spi_set_cs(msg->spi, false);
991                                 udelay(10);
992                                 spi_set_cs(msg->spi, true);
993                         }
994                 }
995
996                 msg->actual_length += xfer->len;
997         }
998
999 out:
1000         if (ret != 0 || !keep_cs)
1001                 spi_set_cs(msg->spi, false);
1002
1003         if (msg->status == -EINPROGRESS)
1004                 msg->status = ret;
1005
1006         if (msg->status && master->handle_err)
1007                 master->handle_err(master, msg);
1008
1009         spi_finalize_current_message(master);
1010
1011         return ret;
1012 }
1013
1014 /**
1015  * spi_finalize_current_transfer - report completion of a transfer
1016  * @master: the master reporting completion
1017  *
1018  * Called by SPI drivers using the core transfer_one_message()
1019  * implementation to notify it that the current interrupt driven
1020  * transfer has finished and the next one may be scheduled.
1021  */
1022 void spi_finalize_current_transfer(struct spi_master *master)
1023 {
1024         complete(&master->xfer_completion);
1025 }
1026 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1027
1028 /**
1029  * __spi_pump_messages - function which processes spi message queue
1030  * @master: master to process queue for
1031  * @in_kthread: true if we are in the context of the message pump thread
1032  *
1033  * This function checks if there is any spi message in the queue that
1034  * needs processing and if so call out to the driver to initialize hardware
1035  * and transfer each message.
1036  *
1037  * Note that it is called both from the kthread itself and also from
1038  * inside spi_sync(); the queue extraction handling at the top of the
1039  * function should deal with this safely.
1040  */
1041 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1042 {
1043         unsigned long flags;
1044         bool was_busy = false;
1045         int ret;
1046
1047         /* Lock queue */
1048         spin_lock_irqsave(&master->queue_lock, flags);
1049
1050         /* Make sure we are not already running a message */
1051         if (master->cur_msg) {
1052                 spin_unlock_irqrestore(&master->queue_lock, flags);
1053                 return;
1054         }
1055
1056         /* If another context is idling the device then defer */
1057         if (master->idling) {
1058                 queue_kthread_work(&master->kworker, &master->pump_messages);
1059                 spin_unlock_irqrestore(&master->queue_lock, flags);
1060                 return;
1061         }
1062
1063         /* Check if the queue is idle */
1064         if (list_empty(&master->queue) || !master->running) {
1065                 if (!master->busy) {
1066                         spin_unlock_irqrestore(&master->queue_lock, flags);
1067                         return;
1068                 }
1069
1070                 /* Only do teardown in the thread */
1071                 if (!in_kthread) {
1072                         queue_kthread_work(&master->kworker,
1073                                            &master->pump_messages);
1074                         spin_unlock_irqrestore(&master->queue_lock, flags);
1075                         return;
1076                 }
1077
1078                 master->busy = false;
1079                 master->idling = true;
1080                 spin_unlock_irqrestore(&master->queue_lock, flags);
1081
1082                 kfree(master->dummy_rx);
1083                 master->dummy_rx = NULL;
1084                 kfree(master->dummy_tx);
1085                 master->dummy_tx = NULL;
1086                 if (master->unprepare_transfer_hardware &&
1087                     master->unprepare_transfer_hardware(master))
1088                         dev_err(&master->dev,
1089                                 "failed to unprepare transfer hardware\n");
1090                 if (master->auto_runtime_pm) {
1091                         pm_runtime_mark_last_busy(master->dev.parent);
1092                         pm_runtime_put_autosuspend(master->dev.parent);
1093                 }
1094                 trace_spi_master_idle(master);
1095
1096                 spin_lock_irqsave(&master->queue_lock, flags);
1097                 master->idling = false;
1098                 spin_unlock_irqrestore(&master->queue_lock, flags);
1099                 return;
1100         }
1101
1102         /* Extract head of queue */
1103         master->cur_msg =
1104                 list_first_entry(&master->queue, struct spi_message, queue);
1105
1106         list_del_init(&master->cur_msg->queue);
1107         if (master->busy)
1108                 was_busy = true;
1109         else
1110                 master->busy = true;
1111         spin_unlock_irqrestore(&master->queue_lock, flags);
1112
1113         if (!was_busy && master->auto_runtime_pm) {
1114                 ret = pm_runtime_get_sync(master->dev.parent);
1115                 if (ret < 0) {
1116                         dev_err(&master->dev, "Failed to power device: %d\n",
1117                                 ret);
1118                         return;
1119                 }
1120         }
1121
1122         if (!was_busy)
1123                 trace_spi_master_busy(master);
1124
1125         if (!was_busy && master->prepare_transfer_hardware) {
1126                 ret = master->prepare_transfer_hardware(master);
1127                 if (ret) {
1128                         dev_err(&master->dev,
1129                                 "failed to prepare transfer hardware\n");
1130
1131                         if (master->auto_runtime_pm)
1132                                 pm_runtime_put(master->dev.parent);
1133                         return;
1134                 }
1135         }
1136
1137         trace_spi_message_start(master->cur_msg);
1138
1139         if (master->prepare_message) {
1140                 ret = master->prepare_message(master, master->cur_msg);
1141                 if (ret) {
1142                         dev_err(&master->dev,
1143                                 "failed to prepare message: %d\n", ret);
1144                         master->cur_msg->status = ret;
1145                         spi_finalize_current_message(master);
1146                         return;
1147                 }
1148                 master->cur_msg_prepared = true;
1149         }
1150
1151         ret = spi_map_msg(master, master->cur_msg);
1152         if (ret) {
1153                 master->cur_msg->status = ret;
1154                 spi_finalize_current_message(master);
1155                 return;
1156         }
1157
1158         ret = master->transfer_one_message(master, master->cur_msg);
1159         if (ret) {
1160                 dev_err(&master->dev,
1161                         "failed to transfer one message from queue\n");
1162                 return;
1163         }
1164 }
1165
1166 /**
1167  * spi_pump_messages - kthread work function which processes spi message queue
1168  * @work: pointer to kthread work struct contained in the master struct
1169  */
1170 static void spi_pump_messages(struct kthread_work *work)
1171 {
1172         struct spi_master *master =
1173                 container_of(work, struct spi_master, pump_messages);
1174
1175         __spi_pump_messages(master, true);
1176 }
1177
1178 static int spi_init_queue(struct spi_master *master)
1179 {
1180         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1181
1182         master->running = false;
1183         master->busy = false;
1184
1185         init_kthread_worker(&master->kworker);
1186         master->kworker_task = kthread_run(kthread_worker_fn,
1187                                            &master->kworker, "%s",
1188                                            dev_name(&master->dev));
1189         if (IS_ERR(master->kworker_task)) {
1190                 dev_err(&master->dev, "failed to create message pump task\n");
1191                 return PTR_ERR(master->kworker_task);
1192         }
1193         init_kthread_work(&master->pump_messages, spi_pump_messages);
1194
1195         /*
1196          * Master config will indicate if this controller should run the
1197          * message pump with high (realtime) priority to reduce the transfer
1198          * latency on the bus by minimising the delay between a transfer
1199          * request and the scheduling of the message pump thread. Without this
1200          * setting the message pump thread will remain at default priority.
1201          */
1202         if (master->rt) {
1203                 dev_info(&master->dev,
1204                         "will run message pump with realtime priority\n");
1205                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1206         }
1207
1208         return 0;
1209 }
1210
1211 /**
1212  * spi_get_next_queued_message() - called by driver to check for queued
1213  * messages
1214  * @master: the master to check for queued messages
1215  *
1216  * If there are more messages in the queue, the next message is returned from
1217  * this call.
1218  *
1219  * Return: the next message in the queue, else NULL if the queue is empty.
1220  */
1221 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1222 {
1223         struct spi_message *next;
1224         unsigned long flags;
1225
1226         /* get a pointer to the next message, if any */
1227         spin_lock_irqsave(&master->queue_lock, flags);
1228         next = list_first_entry_or_null(&master->queue, struct spi_message,
1229                                         queue);
1230         spin_unlock_irqrestore(&master->queue_lock, flags);
1231
1232         return next;
1233 }
1234 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1235
1236 /**
1237  * spi_finalize_current_message() - the current message is complete
1238  * @master: the master to return the message to
1239  *
1240  * Called by the driver to notify the core that the message in the front of the
1241  * queue is complete and can be removed from the queue.
1242  */
1243 void spi_finalize_current_message(struct spi_master *master)
1244 {
1245         struct spi_message *mesg;
1246         unsigned long flags;
1247         int ret;
1248
1249         spin_lock_irqsave(&master->queue_lock, flags);
1250         mesg = master->cur_msg;
1251         spin_unlock_irqrestore(&master->queue_lock, flags);
1252
1253         spi_unmap_msg(master, mesg);
1254
1255         if (master->cur_msg_prepared && master->unprepare_message) {
1256                 ret = master->unprepare_message(master, mesg);
1257                 if (ret) {
1258                         dev_err(&master->dev,
1259                                 "failed to unprepare message: %d\n", ret);
1260                 }
1261         }
1262
1263         spin_lock_irqsave(&master->queue_lock, flags);
1264         master->cur_msg = NULL;
1265         master->cur_msg_prepared = false;
1266         queue_kthread_work(&master->kworker, &master->pump_messages);
1267         spin_unlock_irqrestore(&master->queue_lock, flags);
1268
1269         trace_spi_message_done(mesg);
1270
1271         mesg->state = NULL;
1272         if (mesg->complete)
1273                 mesg->complete(mesg->context);
1274 }
1275 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1276
1277 static int spi_start_queue(struct spi_master *master)
1278 {
1279         unsigned long flags;
1280
1281         spin_lock_irqsave(&master->queue_lock, flags);
1282
1283         if (master->running || master->busy) {
1284                 spin_unlock_irqrestore(&master->queue_lock, flags);
1285                 return -EBUSY;
1286         }
1287
1288         master->running = true;
1289         master->cur_msg = NULL;
1290         spin_unlock_irqrestore(&master->queue_lock, flags);
1291
1292         queue_kthread_work(&master->kworker, &master->pump_messages);
1293
1294         return 0;
1295 }
1296
1297 static int spi_stop_queue(struct spi_master *master)
1298 {
1299         unsigned long flags;
1300         unsigned limit = 500;
1301         int ret = 0;
1302
1303         spin_lock_irqsave(&master->queue_lock, flags);
1304
1305         /*
1306          * This is a bit lame, but is optimized for the common execution path.
1307          * A wait_queue on the master->busy could be used, but then the common
1308          * execution path (pump_messages) would be required to call wake_up or
1309          * friends on every SPI message. Do this instead.
1310          */
1311         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1312                 spin_unlock_irqrestore(&master->queue_lock, flags);
1313                 usleep_range(10000, 11000);
1314                 spin_lock_irqsave(&master->queue_lock, flags);
1315         }
1316
1317         if (!list_empty(&master->queue) || master->busy)
1318                 ret = -EBUSY;
1319         else
1320                 master->running = false;
1321
1322         spin_unlock_irqrestore(&master->queue_lock, flags);
1323
1324         if (ret) {
1325                 dev_warn(&master->dev,
1326                          "could not stop message queue\n");
1327                 return ret;
1328         }
1329         return ret;
1330 }
1331
1332 static int spi_destroy_queue(struct spi_master *master)
1333 {
1334         int ret;
1335
1336         ret = spi_stop_queue(master);
1337
1338         /*
1339          * flush_kthread_worker will block until all work is done.
1340          * If the reason that stop_queue timed out is that the work will never
1341          * finish, then it does no good to call flush/stop thread, so
1342          * return anyway.
1343          */
1344         if (ret) {
1345                 dev_err(&master->dev, "problem destroying queue\n");
1346                 return ret;
1347         }
1348
1349         flush_kthread_worker(&master->kworker);
1350         kthread_stop(master->kworker_task);
1351
1352         return 0;
1353 }
1354
1355 static int __spi_queued_transfer(struct spi_device *spi,
1356                                  struct spi_message *msg,
1357                                  bool need_pump)
1358 {
1359         struct spi_master *master = spi->master;
1360         unsigned long flags;
1361
1362         spin_lock_irqsave(&master->queue_lock, flags);
1363
1364         if (!master->running) {
1365                 spin_unlock_irqrestore(&master->queue_lock, flags);
1366                 return -ESHUTDOWN;
1367         }
1368         msg->actual_length = 0;
1369         msg->status = -EINPROGRESS;
1370
1371         list_add_tail(&msg->queue, &master->queue);
1372         if (!master->busy && need_pump)
1373                 queue_kthread_work(&master->kworker, &master->pump_messages);
1374
1375         spin_unlock_irqrestore(&master->queue_lock, flags);
1376         return 0;
1377 }
1378
1379 /**
1380  * spi_queued_transfer - transfer function for queued transfers
1381  * @spi: spi device which is requesting transfer
1382  * @msg: spi message which is to handled is queued to driver queue
1383  *
1384  * Return: zero on success, else a negative error code.
1385  */
1386 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1387 {
1388         return __spi_queued_transfer(spi, msg, true);
1389 }
1390
1391 static int spi_master_initialize_queue(struct spi_master *master)
1392 {
1393         int ret;
1394
1395         master->transfer = spi_queued_transfer;
1396         if (!master->transfer_one_message)
1397                 master->transfer_one_message = spi_transfer_one_message;
1398
1399         /* Initialize and start queue */
1400         ret = spi_init_queue(master);
1401         if (ret) {
1402                 dev_err(&master->dev, "problem initializing queue\n");
1403                 goto err_init_queue;
1404         }
1405         master->queued = true;
1406         ret = spi_start_queue(master);
1407         if (ret) {
1408                 dev_err(&master->dev, "problem starting queue\n");
1409                 goto err_start_queue;
1410         }
1411
1412         return 0;
1413
1414 err_start_queue:
1415         spi_destroy_queue(master);
1416 err_init_queue:
1417         return ret;
1418 }
1419
1420 /*-------------------------------------------------------------------------*/
1421
1422 #if defined(CONFIG_OF)
1423 static struct spi_device *
1424 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1425 {
1426         struct spi_device *spi;
1427         int rc;
1428         u32 value;
1429
1430         /* Alloc an spi_device */
1431         spi = spi_alloc_device(master);
1432         if (!spi) {
1433                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1434                         nc->full_name);
1435                 rc = -ENOMEM;
1436                 goto err_out;
1437         }
1438
1439         /* Select device driver */
1440         rc = of_modalias_node(nc, spi->modalias,
1441                                 sizeof(spi->modalias));
1442         if (rc < 0) {
1443                 dev_err(&master->dev, "cannot find modalias for %s\n",
1444                         nc->full_name);
1445                 goto err_out;
1446         }
1447
1448         /* Device address */
1449         rc = of_property_read_u32(nc, "reg", &value);
1450         if (rc) {
1451                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1452                         nc->full_name, rc);
1453                 goto err_out;
1454         }
1455         spi->chip_select = value;
1456
1457         /* Mode (clock phase/polarity/etc.) */
1458         if (of_find_property(nc, "spi-cpha", NULL))
1459                 spi->mode |= SPI_CPHA;
1460         if (of_find_property(nc, "spi-cpol", NULL))
1461                 spi->mode |= SPI_CPOL;
1462         if (of_find_property(nc, "spi-cs-high", NULL))
1463                 spi->mode |= SPI_CS_HIGH;
1464         if (of_find_property(nc, "spi-3wire", NULL))
1465                 spi->mode |= SPI_3WIRE;
1466         if (of_find_property(nc, "spi-lsb-first", NULL))
1467                 spi->mode |= SPI_LSB_FIRST;
1468
1469         /* Device DUAL/QUAD mode */
1470         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1471                 switch (value) {
1472                 case 1:
1473                         break;
1474                 case 2:
1475                         spi->mode |= SPI_TX_DUAL;
1476                         break;
1477                 case 4:
1478                         spi->mode |= SPI_TX_QUAD;
1479                         break;
1480                 default:
1481                         dev_warn(&master->dev,
1482                                 "spi-tx-bus-width %d not supported\n",
1483                                 value);
1484                         break;
1485                 }
1486         }
1487
1488         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1489                 switch (value) {
1490                 case 1:
1491                         break;
1492                 case 2:
1493                         spi->mode |= SPI_RX_DUAL;
1494                         break;
1495                 case 4:
1496                         spi->mode |= SPI_RX_QUAD;
1497                         break;
1498                 default:
1499                         dev_warn(&master->dev,
1500                                 "spi-rx-bus-width %d not supported\n",
1501                                 value);
1502                         break;
1503                 }
1504         }
1505
1506         /* Device speed */
1507         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1508         if (rc) {
1509                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1510                         nc->full_name, rc);
1511                 goto err_out;
1512         }
1513         spi->max_speed_hz = value;
1514
1515         /* Store a pointer to the node in the device structure */
1516         of_node_get(nc);
1517         spi->dev.of_node = nc;
1518
1519         /* Register the new device */
1520         rc = spi_add_device(spi);
1521         if (rc) {
1522                 dev_err(&master->dev, "spi_device register error %s\n",
1523                         nc->full_name);
1524                 goto err_out;
1525         }
1526
1527         return spi;
1528
1529 err_out:
1530         spi_dev_put(spi);
1531         return ERR_PTR(rc);
1532 }
1533
1534 /**
1535  * of_register_spi_devices() - Register child devices onto the SPI bus
1536  * @master:     Pointer to spi_master device
1537  *
1538  * Registers an spi_device for each child node of master node which has a 'reg'
1539  * property.
1540  */
1541 static void of_register_spi_devices(struct spi_master *master)
1542 {
1543         struct spi_device *spi;
1544         struct device_node *nc;
1545
1546         if (!master->dev.of_node)
1547                 return;
1548
1549         for_each_available_child_of_node(master->dev.of_node, nc) {
1550                 spi = of_register_spi_device(master, nc);
1551                 if (IS_ERR(spi))
1552                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1553                                 nc->full_name);
1554         }
1555 }
1556 #else
1557 static void of_register_spi_devices(struct spi_master *master) { }
1558 #endif
1559
1560 #ifdef CONFIG_ACPI
1561 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1562 {
1563         struct spi_device *spi = data;
1564
1565         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1566                 struct acpi_resource_spi_serialbus *sb;
1567
1568                 sb = &ares->data.spi_serial_bus;
1569                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1570                         spi->chip_select = sb->device_selection;
1571                         spi->max_speed_hz = sb->connection_speed;
1572
1573                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1574                                 spi->mode |= SPI_CPHA;
1575                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1576                                 spi->mode |= SPI_CPOL;
1577                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1578                                 spi->mode |= SPI_CS_HIGH;
1579                 }
1580         } else if (spi->irq < 0) {
1581                 struct resource r;
1582
1583                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1584                         spi->irq = r.start;
1585         }
1586
1587         /* Always tell the ACPI core to skip this resource */
1588         return 1;
1589 }
1590
1591 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1592                                        void *data, void **return_value)
1593 {
1594         struct spi_master *master = data;
1595         struct list_head resource_list;
1596         struct acpi_device *adev;
1597         struct spi_device *spi;
1598         int ret;
1599
1600         if (acpi_bus_get_device(handle, &adev))
1601                 return AE_OK;
1602         if (acpi_bus_get_status(adev) || !adev->status.present)
1603                 return AE_OK;
1604
1605         spi = spi_alloc_device(master);
1606         if (!spi) {
1607                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1608                         dev_name(&adev->dev));
1609                 return AE_NO_MEMORY;
1610         }
1611
1612         ACPI_COMPANION_SET(&spi->dev, adev);
1613         spi->irq = -1;
1614
1615         INIT_LIST_HEAD(&resource_list);
1616         ret = acpi_dev_get_resources(adev, &resource_list,
1617                                      acpi_spi_add_resource, spi);
1618         acpi_dev_free_resource_list(&resource_list);
1619
1620         if (ret < 0 || !spi->max_speed_hz) {
1621                 spi_dev_put(spi);
1622                 return AE_OK;
1623         }
1624
1625         adev->power.flags.ignore_parent = true;
1626         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1627         if (spi_add_device(spi)) {
1628                 adev->power.flags.ignore_parent = false;
1629                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1630                         dev_name(&adev->dev));
1631                 spi_dev_put(spi);
1632         }
1633
1634         return AE_OK;
1635 }
1636
1637 static void acpi_register_spi_devices(struct spi_master *master)
1638 {
1639         acpi_status status;
1640         acpi_handle handle;
1641
1642         handle = ACPI_HANDLE(master->dev.parent);
1643         if (!handle)
1644                 return;
1645
1646         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1647                                      acpi_spi_add_device, NULL,
1648                                      master, NULL);
1649         if (ACPI_FAILURE(status))
1650                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1651 }
1652 #else
1653 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1654 #endif /* CONFIG_ACPI */
1655
1656 static void spi_master_release(struct device *dev)
1657 {
1658         struct spi_master *master;
1659
1660         master = container_of(dev, struct spi_master, dev);
1661         kfree(master);
1662 }
1663
1664 static struct class spi_master_class = {
1665         .name           = "spi_master",
1666         .owner          = THIS_MODULE,
1667         .dev_release    = spi_master_release,
1668         .dev_groups     = spi_master_groups,
1669 };
1670
1671
1672 /**
1673  * spi_alloc_master - allocate SPI master controller
1674  * @dev: the controller, possibly using the platform_bus
1675  * @size: how much zeroed driver-private data to allocate; the pointer to this
1676  *      memory is in the driver_data field of the returned device,
1677  *      accessible with spi_master_get_devdata().
1678  * Context: can sleep
1679  *
1680  * This call is used only by SPI master controller drivers, which are the
1681  * only ones directly touching chip registers.  It's how they allocate
1682  * an spi_master structure, prior to calling spi_register_master().
1683  *
1684  * This must be called from context that can sleep.
1685  *
1686  * The caller is responsible for assigning the bus number and initializing
1687  * the master's methods before calling spi_register_master(); and (after errors
1688  * adding the device) calling spi_master_put() to prevent a memory leak.
1689  *
1690  * Return: the SPI master structure on success, else NULL.
1691  */
1692 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1693 {
1694         struct spi_master       *master;
1695
1696         if (!dev)
1697                 return NULL;
1698
1699         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1700         if (!master)
1701                 return NULL;
1702
1703         device_initialize(&master->dev);
1704         master->bus_num = -1;
1705         master->num_chipselect = 1;
1706         master->dev.class = &spi_master_class;
1707         master->dev.parent = get_device(dev);
1708         spi_master_set_devdata(master, &master[1]);
1709
1710         return master;
1711 }
1712 EXPORT_SYMBOL_GPL(spi_alloc_master);
1713
1714 #ifdef CONFIG_OF
1715 static int of_spi_register_master(struct spi_master *master)
1716 {
1717         int nb, i, *cs;
1718         struct device_node *np = master->dev.of_node;
1719
1720         if (!np)
1721                 return 0;
1722
1723         nb = of_gpio_named_count(np, "cs-gpios");
1724         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1725
1726         /* Return error only for an incorrectly formed cs-gpios property */
1727         if (nb == 0 || nb == -ENOENT)
1728                 return 0;
1729         else if (nb < 0)
1730                 return nb;
1731
1732         cs = devm_kzalloc(&master->dev,
1733                           sizeof(int) * master->num_chipselect,
1734                           GFP_KERNEL);
1735         master->cs_gpios = cs;
1736
1737         if (!master->cs_gpios)
1738                 return -ENOMEM;
1739
1740         for (i = 0; i < master->num_chipselect; i++)
1741                 cs[i] = -ENOENT;
1742
1743         for (i = 0; i < nb; i++)
1744                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1745
1746         return 0;
1747 }
1748 #else
1749 static int of_spi_register_master(struct spi_master *master)
1750 {
1751         return 0;
1752 }
1753 #endif
1754
1755 /**
1756  * spi_register_master - register SPI master controller
1757  * @master: initialized master, originally from spi_alloc_master()
1758  * Context: can sleep
1759  *
1760  * SPI master controllers connect to their drivers using some non-SPI bus,
1761  * such as the platform bus.  The final stage of probe() in that code
1762  * includes calling spi_register_master() to hook up to this SPI bus glue.
1763  *
1764  * SPI controllers use board specific (often SOC specific) bus numbers,
1765  * and board-specific addressing for SPI devices combines those numbers
1766  * with chip select numbers.  Since SPI does not directly support dynamic
1767  * device identification, boards need configuration tables telling which
1768  * chip is at which address.
1769  *
1770  * This must be called from context that can sleep.  It returns zero on
1771  * success, else a negative error code (dropping the master's refcount).
1772  * After a successful return, the caller is responsible for calling
1773  * spi_unregister_master().
1774  *
1775  * Return: zero on success, else a negative error code.
1776  */
1777 int spi_register_master(struct spi_master *master)
1778 {
1779         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1780         struct device           *dev = master->dev.parent;
1781         struct boardinfo        *bi;
1782         int                     status = -ENODEV;
1783         int                     dynamic = 0;
1784
1785         if (!dev)
1786                 return -ENODEV;
1787
1788         status = of_spi_register_master(master);
1789         if (status)
1790                 return status;
1791
1792         /* even if it's just one always-selected device, there must
1793          * be at least one chipselect
1794          */
1795         if (master->num_chipselect == 0)
1796                 return -EINVAL;
1797
1798         if ((master->bus_num < 0) && master->dev.of_node)
1799                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1800
1801         /* convention:  dynamically assigned bus IDs count down from the max */
1802         if (master->bus_num < 0) {
1803                 /* FIXME switch to an IDR based scheme, something like
1804                  * I2C now uses, so we can't run out of "dynamic" IDs
1805                  */
1806                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1807                 dynamic = 1;
1808         }
1809
1810         INIT_LIST_HEAD(&master->queue);
1811         spin_lock_init(&master->queue_lock);
1812         spin_lock_init(&master->bus_lock_spinlock);
1813         mutex_init(&master->bus_lock_mutex);
1814         master->bus_lock_flag = 0;
1815         init_completion(&master->xfer_completion);
1816         if (!master->max_dma_len)
1817                 master->max_dma_len = INT_MAX;
1818
1819         /* register the device, then userspace will see it.
1820          * registration fails if the bus ID is in use.
1821          */
1822         dev_set_name(&master->dev, "spi%u", master->bus_num);
1823         status = device_add(&master->dev);
1824         if (status < 0)
1825                 goto done;
1826         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1827                         dynamic ? " (dynamic)" : "");
1828
1829         /* If we're using a queued driver, start the queue */
1830         if (master->transfer)
1831                 dev_info(dev, "master is unqueued, this is deprecated\n");
1832         else {
1833                 status = spi_master_initialize_queue(master);
1834                 if (status) {
1835                         device_del(&master->dev);
1836                         goto done;
1837                 }
1838         }
1839         /* add statistics */
1840         spin_lock_init(&master->statistics.lock);
1841
1842         mutex_lock(&board_lock);
1843         list_add_tail(&master->list, &spi_master_list);
1844         list_for_each_entry(bi, &board_list, list)
1845                 spi_match_master_to_boardinfo(master, &bi->board_info);
1846         mutex_unlock(&board_lock);
1847
1848         /* Register devices from the device tree and ACPI */
1849         of_register_spi_devices(master);
1850         acpi_register_spi_devices(master);
1851 done:
1852         return status;
1853 }
1854 EXPORT_SYMBOL_GPL(spi_register_master);
1855
1856 static void devm_spi_unregister(struct device *dev, void *res)
1857 {
1858         spi_unregister_master(*(struct spi_master **)res);
1859 }
1860
1861 /**
1862  * dev_spi_register_master - register managed SPI master controller
1863  * @dev:    device managing SPI master
1864  * @master: initialized master, originally from spi_alloc_master()
1865  * Context: can sleep
1866  *
1867  * Register a SPI device as with spi_register_master() which will
1868  * automatically be unregister
1869  *
1870  * Return: zero on success, else a negative error code.
1871  */
1872 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1873 {
1874         struct spi_master **ptr;
1875         int ret;
1876
1877         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1878         if (!ptr)
1879                 return -ENOMEM;
1880
1881         ret = spi_register_master(master);
1882         if (!ret) {
1883                 *ptr = master;
1884                 devres_add(dev, ptr);
1885         } else {
1886                 devres_free(ptr);
1887         }
1888
1889         return ret;
1890 }
1891 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1892
1893 static int __unregister(struct device *dev, void *null)
1894 {
1895         spi_unregister_device(to_spi_device(dev));
1896         return 0;
1897 }
1898
1899 /**
1900  * spi_unregister_master - unregister SPI master controller
1901  * @master: the master being unregistered
1902  * Context: can sleep
1903  *
1904  * This call is used only by SPI master controller drivers, which are the
1905  * only ones directly touching chip registers.
1906  *
1907  * This must be called from context that can sleep.
1908  */
1909 void spi_unregister_master(struct spi_master *master)
1910 {
1911         int dummy;
1912
1913         if (master->queued) {
1914                 if (spi_destroy_queue(master))
1915                         dev_err(&master->dev, "queue remove failed\n");
1916         }
1917
1918         mutex_lock(&board_lock);
1919         list_del(&master->list);
1920         mutex_unlock(&board_lock);
1921
1922         dummy = device_for_each_child(&master->dev, NULL, __unregister);
1923         device_unregister(&master->dev);
1924 }
1925 EXPORT_SYMBOL_GPL(spi_unregister_master);
1926
1927 int spi_master_suspend(struct spi_master *master)
1928 {
1929         int ret;
1930
1931         /* Basically no-ops for non-queued masters */
1932         if (!master->queued)
1933                 return 0;
1934
1935         ret = spi_stop_queue(master);
1936         if (ret)
1937                 dev_err(&master->dev, "queue stop failed\n");
1938
1939         return ret;
1940 }
1941 EXPORT_SYMBOL_GPL(spi_master_suspend);
1942
1943 int spi_master_resume(struct spi_master *master)
1944 {
1945         int ret;
1946
1947         if (!master->queued)
1948                 return 0;
1949
1950         ret = spi_start_queue(master);
1951         if (ret)
1952                 dev_err(&master->dev, "queue restart failed\n");
1953
1954         return ret;
1955 }
1956 EXPORT_SYMBOL_GPL(spi_master_resume);
1957
1958 static int __spi_master_match(struct device *dev, const void *data)
1959 {
1960         struct spi_master *m;
1961         const u16 *bus_num = data;
1962
1963         m = container_of(dev, struct spi_master, dev);
1964         return m->bus_num == *bus_num;
1965 }
1966
1967 /**
1968  * spi_busnum_to_master - look up master associated with bus_num
1969  * @bus_num: the master's bus number
1970  * Context: can sleep
1971  *
1972  * This call may be used with devices that are registered after
1973  * arch init time.  It returns a refcounted pointer to the relevant
1974  * spi_master (which the caller must release), or NULL if there is
1975  * no such master registered.
1976  *
1977  * Return: the SPI master structure on success, else NULL.
1978  */
1979 struct spi_master *spi_busnum_to_master(u16 bus_num)
1980 {
1981         struct device           *dev;
1982         struct spi_master       *master = NULL;
1983
1984         dev = class_find_device(&spi_master_class, NULL, &bus_num,
1985                                 __spi_master_match);
1986         if (dev)
1987                 master = container_of(dev, struct spi_master, dev);
1988         /* reference got in class_find_device */
1989         return master;
1990 }
1991 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1992
1993
1994 /*-------------------------------------------------------------------------*/
1995
1996 /* Core methods for SPI master protocol drivers.  Some of the
1997  * other core methods are currently defined as inline functions.
1998  */
1999
2000 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2001 {
2002         if (master->bits_per_word_mask) {
2003                 /* Only 32 bits fit in the mask */
2004                 if (bits_per_word > 32)
2005                         return -EINVAL;
2006                 if (!(master->bits_per_word_mask &
2007                                 SPI_BPW_MASK(bits_per_word)))
2008                         return -EINVAL;
2009         }
2010
2011         return 0;
2012 }
2013
2014 /**
2015  * spi_setup - setup SPI mode and clock rate
2016  * @spi: the device whose settings are being modified
2017  * Context: can sleep, and no requests are queued to the device
2018  *
2019  * SPI protocol drivers may need to update the transfer mode if the
2020  * device doesn't work with its default.  They may likewise need
2021  * to update clock rates or word sizes from initial values.  This function
2022  * changes those settings, and must be called from a context that can sleep.
2023  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2024  * effect the next time the device is selected and data is transferred to
2025  * or from it.  When this function returns, the spi device is deselected.
2026  *
2027  * Note that this call will fail if the protocol driver specifies an option
2028  * that the underlying controller or its driver does not support.  For
2029  * example, not all hardware supports wire transfers using nine bit words,
2030  * LSB-first wire encoding, or active-high chipselects.
2031  *
2032  * Return: zero on success, else a negative error code.
2033  */
2034 int spi_setup(struct spi_device *spi)
2035 {
2036         unsigned        bad_bits, ugly_bits;
2037         int             status;
2038
2039         /* check mode to prevent that DUAL and QUAD set at the same time
2040          */
2041         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2042                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2043                 dev_err(&spi->dev,
2044                 "setup: can not select dual and quad at the same time\n");
2045                 return -EINVAL;
2046         }
2047         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2048          */
2049         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2050                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2051                 return -EINVAL;
2052         /* help drivers fail *cleanly* when they need options
2053          * that aren't supported with their current master
2054          */
2055         bad_bits = spi->mode & ~spi->master->mode_bits;
2056         ugly_bits = bad_bits &
2057                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2058         if (ugly_bits) {
2059                 dev_warn(&spi->dev,
2060                          "setup: ignoring unsupported mode bits %x\n",
2061                          ugly_bits);
2062                 spi->mode &= ~ugly_bits;
2063                 bad_bits &= ~ugly_bits;
2064         }
2065         if (bad_bits) {
2066                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2067                         bad_bits);
2068                 return -EINVAL;
2069         }
2070
2071         if (!spi->bits_per_word)
2072                 spi->bits_per_word = 8;
2073
2074         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2075         if (status)
2076                 return status;
2077
2078         if (!spi->max_speed_hz)
2079                 spi->max_speed_hz = spi->master->max_speed_hz;
2080
2081         if (spi->master->setup)
2082                 status = spi->master->setup(spi);
2083
2084         spi_set_cs(spi, false);
2085
2086         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2087                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2088                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2089                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2090                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2091                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2092                         spi->bits_per_word, spi->max_speed_hz,
2093                         status);
2094
2095         return status;
2096 }
2097 EXPORT_SYMBOL_GPL(spi_setup);
2098
2099 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2100 {
2101         struct spi_master *master = spi->master;
2102         struct spi_transfer *xfer;
2103         int w_size;
2104
2105         if (list_empty(&message->transfers))
2106                 return -EINVAL;
2107
2108         /* Half-duplex links include original MicroWire, and ones with
2109          * only one data pin like SPI_3WIRE (switches direction) or where
2110          * either MOSI or MISO is missing.  They can also be caused by
2111          * software limitations.
2112          */
2113         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2114                         || (spi->mode & SPI_3WIRE)) {
2115                 unsigned flags = master->flags;
2116
2117                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2118                         if (xfer->rx_buf && xfer->tx_buf)
2119                                 return -EINVAL;
2120                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2121                                 return -EINVAL;
2122                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2123                                 return -EINVAL;
2124                 }
2125         }
2126
2127         /**
2128          * Set transfer bits_per_word and max speed as spi device default if
2129          * it is not set for this transfer.
2130          * Set transfer tx_nbits and rx_nbits as single transfer default
2131          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2132          */
2133         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2134                 message->frame_length += xfer->len;
2135                 if (!xfer->bits_per_word)
2136                         xfer->bits_per_word = spi->bits_per_word;
2137
2138                 if (!xfer->speed_hz)
2139                         xfer->speed_hz = spi->max_speed_hz;
2140                 if (!xfer->speed_hz)
2141                         xfer->speed_hz = master->max_speed_hz;
2142
2143                 if (master->max_speed_hz &&
2144                     xfer->speed_hz > master->max_speed_hz)
2145                         xfer->speed_hz = master->max_speed_hz;
2146
2147                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2148                         return -EINVAL;
2149
2150                 /*
2151                  * SPI transfer length should be multiple of SPI word size
2152                  * where SPI word size should be power-of-two multiple
2153                  */
2154                 if (xfer->bits_per_word <= 8)
2155                         w_size = 1;
2156                 else if (xfer->bits_per_word <= 16)
2157                         w_size = 2;
2158                 else
2159                         w_size = 4;
2160
2161                 /* No partial transfers accepted */
2162                 if (xfer->len % w_size)
2163                         return -EINVAL;
2164
2165                 if (xfer->speed_hz && master->min_speed_hz &&
2166                     xfer->speed_hz < master->min_speed_hz)
2167                         return -EINVAL;
2168
2169                 if (xfer->tx_buf && !xfer->tx_nbits)
2170                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2171                 if (xfer->rx_buf && !xfer->rx_nbits)
2172                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2173                 /* check transfer tx/rx_nbits:
2174                  * 1. check the value matches one of single, dual and quad
2175                  * 2. check tx/rx_nbits match the mode in spi_device
2176                  */
2177                 if (xfer->tx_buf) {
2178                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2179                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2180                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2181                                 return -EINVAL;
2182                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2183                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2184                                 return -EINVAL;
2185                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2186                                 !(spi->mode & SPI_TX_QUAD))
2187                                 return -EINVAL;
2188                 }
2189                 /* check transfer rx_nbits */
2190                 if (xfer->rx_buf) {
2191                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2192                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2193                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2194                                 return -EINVAL;
2195                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2196                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2197                                 return -EINVAL;
2198                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2199                                 !(spi->mode & SPI_RX_QUAD))
2200                                 return -EINVAL;
2201                 }
2202         }
2203
2204         message->status = -EINPROGRESS;
2205
2206         return 0;
2207 }
2208
2209 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2210 {
2211         struct spi_master *master = spi->master;
2212
2213         message->spi = spi;
2214
2215         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2216         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2217
2218         trace_spi_message_submit(message);
2219
2220         return master->transfer(spi, message);
2221 }
2222
2223 /**
2224  * spi_async - asynchronous SPI transfer
2225  * @spi: device with which data will be exchanged
2226  * @message: describes the data transfers, including completion callback
2227  * Context: any (irqs may be blocked, etc)
2228  *
2229  * This call may be used in_irq and other contexts which can't sleep,
2230  * as well as from task contexts which can sleep.
2231  *
2232  * The completion callback is invoked in a context which can't sleep.
2233  * Before that invocation, the value of message->status is undefined.
2234  * When the callback is issued, message->status holds either zero (to
2235  * indicate complete success) or a negative error code.  After that
2236  * callback returns, the driver which issued the transfer request may
2237  * deallocate the associated memory; it's no longer in use by any SPI
2238  * core or controller driver code.
2239  *
2240  * Note that although all messages to a spi_device are handled in
2241  * FIFO order, messages may go to different devices in other orders.
2242  * Some device might be higher priority, or have various "hard" access
2243  * time requirements, for example.
2244  *
2245  * On detection of any fault during the transfer, processing of
2246  * the entire message is aborted, and the device is deselected.
2247  * Until returning from the associated message completion callback,
2248  * no other spi_message queued to that device will be processed.
2249  * (This rule applies equally to all the synchronous transfer calls,
2250  * which are wrappers around this core asynchronous primitive.)
2251  *
2252  * Return: zero on success, else a negative error code.
2253  */
2254 int spi_async(struct spi_device *spi, struct spi_message *message)
2255 {
2256         struct spi_master *master = spi->master;
2257         int ret;
2258         unsigned long flags;
2259
2260         ret = __spi_validate(spi, message);
2261         if (ret != 0)
2262                 return ret;
2263
2264         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2265
2266         if (master->bus_lock_flag)
2267                 ret = -EBUSY;
2268         else
2269                 ret = __spi_async(spi, message);
2270
2271         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2272
2273         return ret;
2274 }
2275 EXPORT_SYMBOL_GPL(spi_async);
2276
2277 /**
2278  * spi_async_locked - version of spi_async with exclusive bus usage
2279  * @spi: device with which data will be exchanged
2280  * @message: describes the data transfers, including completion callback
2281  * Context: any (irqs may be blocked, etc)
2282  *
2283  * This call may be used in_irq and other contexts which can't sleep,
2284  * as well as from task contexts which can sleep.
2285  *
2286  * The completion callback is invoked in a context which can't sleep.
2287  * Before that invocation, the value of message->status is undefined.
2288  * When the callback is issued, message->status holds either zero (to
2289  * indicate complete success) or a negative error code.  After that
2290  * callback returns, the driver which issued the transfer request may
2291  * deallocate the associated memory; it's no longer in use by any SPI
2292  * core or controller driver code.
2293  *
2294  * Note that although all messages to a spi_device are handled in
2295  * FIFO order, messages may go to different devices in other orders.
2296  * Some device might be higher priority, or have various "hard" access
2297  * time requirements, for example.
2298  *
2299  * On detection of any fault during the transfer, processing of
2300  * the entire message is aborted, and the device is deselected.
2301  * Until returning from the associated message completion callback,
2302  * no other spi_message queued to that device will be processed.
2303  * (This rule applies equally to all the synchronous transfer calls,
2304  * which are wrappers around this core asynchronous primitive.)
2305  *
2306  * Return: zero on success, else a negative error code.
2307  */
2308 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2309 {
2310         struct spi_master *master = spi->master;
2311         int ret;
2312         unsigned long flags;
2313
2314         ret = __spi_validate(spi, message);
2315         if (ret != 0)
2316                 return ret;
2317
2318         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2319
2320         ret = __spi_async(spi, message);
2321
2322         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2323
2324         return ret;
2325
2326 }
2327 EXPORT_SYMBOL_GPL(spi_async_locked);
2328
2329
2330 /*-------------------------------------------------------------------------*/
2331
2332 /* Utility methods for SPI master protocol drivers, layered on
2333  * top of the core.  Some other utility methods are defined as
2334  * inline functions.
2335  */
2336
2337 static void spi_complete(void *arg)
2338 {
2339         complete(arg);
2340 }
2341
2342 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2343                       int bus_locked)
2344 {
2345         DECLARE_COMPLETION_ONSTACK(done);
2346         int status;
2347         struct spi_master *master = spi->master;
2348         unsigned long flags;
2349
2350         status = __spi_validate(spi, message);
2351         if (status != 0)
2352                 return status;
2353
2354         message->complete = spi_complete;
2355         message->context = &done;
2356         message->spi = spi;
2357
2358         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2359         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2360
2361         if (!bus_locked)
2362                 mutex_lock(&master->bus_lock_mutex);
2363
2364         /* If we're not using the legacy transfer method then we will
2365          * try to transfer in the calling context so special case.
2366          * This code would be less tricky if we could remove the
2367          * support for driver implemented message queues.
2368          */
2369         if (master->transfer == spi_queued_transfer) {
2370                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2371
2372                 trace_spi_message_submit(message);
2373
2374                 status = __spi_queued_transfer(spi, message, false);
2375
2376                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2377         } else {
2378                 status = spi_async_locked(spi, message);
2379         }
2380
2381         if (!bus_locked)
2382                 mutex_unlock(&master->bus_lock_mutex);
2383
2384         if (status == 0) {
2385                 /* Push out the messages in the calling context if we
2386                  * can.
2387                  */
2388                 if (master->transfer == spi_queued_transfer) {
2389                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2390                                                        spi_sync_immediate);
2391                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2392                                                        spi_sync_immediate);
2393                         __spi_pump_messages(master, false);
2394                 }
2395
2396                 wait_for_completion(&done);
2397                 status = message->status;
2398         }
2399         message->context = NULL;
2400         return status;
2401 }
2402
2403 /**
2404  * spi_sync - blocking/synchronous SPI data transfers
2405  * @spi: device with which data will be exchanged
2406  * @message: describes the data transfers
2407  * Context: can sleep
2408  *
2409  * This call may only be used from a context that may sleep.  The sleep
2410  * is non-interruptible, and has no timeout.  Low-overhead controller
2411  * drivers may DMA directly into and out of the message buffers.
2412  *
2413  * Note that the SPI device's chip select is active during the message,
2414  * and then is normally disabled between messages.  Drivers for some
2415  * frequently-used devices may want to minimize costs of selecting a chip,
2416  * by leaving it selected in anticipation that the next message will go
2417  * to the same chip.  (That may increase power usage.)
2418  *
2419  * Also, the caller is guaranteeing that the memory associated with the
2420  * message will not be freed before this call returns.
2421  *
2422  * Return: zero on success, else a negative error code.
2423  */
2424 int spi_sync(struct spi_device *spi, struct spi_message *message)
2425 {
2426         return __spi_sync(spi, message, 0);
2427 }
2428 EXPORT_SYMBOL_GPL(spi_sync);
2429
2430 /**
2431  * spi_sync_locked - version of spi_sync with exclusive bus usage
2432  * @spi: device with which data will be exchanged
2433  * @message: describes the data transfers
2434  * Context: can sleep
2435  *
2436  * This call may only be used from a context that may sleep.  The sleep
2437  * is non-interruptible, and has no timeout.  Low-overhead controller
2438  * drivers may DMA directly into and out of the message buffers.
2439  *
2440  * This call should be used by drivers that require exclusive access to the
2441  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2442  * be released by a spi_bus_unlock call when the exclusive access is over.
2443  *
2444  * Return: zero on success, else a negative error code.
2445  */
2446 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2447 {
2448         return __spi_sync(spi, message, 1);
2449 }
2450 EXPORT_SYMBOL_GPL(spi_sync_locked);
2451
2452 /**
2453  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2454  * @master: SPI bus master that should be locked for exclusive bus access
2455  * Context: can sleep
2456  *
2457  * This call may only be used from a context that may sleep.  The sleep
2458  * is non-interruptible, and has no timeout.
2459  *
2460  * This call should be used by drivers that require exclusive access to the
2461  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2462  * exclusive access is over. Data transfer must be done by spi_sync_locked
2463  * and spi_async_locked calls when the SPI bus lock is held.
2464  *
2465  * Return: always zero.
2466  */
2467 int spi_bus_lock(struct spi_master *master)
2468 {
2469         unsigned long flags;
2470
2471         mutex_lock(&master->bus_lock_mutex);
2472
2473         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2474         master->bus_lock_flag = 1;
2475         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2476
2477         /* mutex remains locked until spi_bus_unlock is called */
2478
2479         return 0;
2480 }
2481 EXPORT_SYMBOL_GPL(spi_bus_lock);
2482
2483 /**
2484  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2485  * @master: SPI bus master that was locked for exclusive bus access
2486  * Context: can sleep
2487  *
2488  * This call may only be used from a context that may sleep.  The sleep
2489  * is non-interruptible, and has no timeout.
2490  *
2491  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2492  * call.
2493  *
2494  * Return: always zero.
2495  */
2496 int spi_bus_unlock(struct spi_master *master)
2497 {
2498         master->bus_lock_flag = 0;
2499
2500         mutex_unlock(&master->bus_lock_mutex);
2501
2502         return 0;
2503 }
2504 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2505
2506 /* portable code must never pass more than 32 bytes */
2507 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2508
2509 static u8       *buf;
2510
2511 /**
2512  * spi_write_then_read - SPI synchronous write followed by read
2513  * @spi: device with which data will be exchanged
2514  * @txbuf: data to be written (need not be dma-safe)
2515  * @n_tx: size of txbuf, in bytes
2516  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2517  * @n_rx: size of rxbuf, in bytes
2518  * Context: can sleep
2519  *
2520  * This performs a half duplex MicroWire style transaction with the
2521  * device, sending txbuf and then reading rxbuf.  The return value
2522  * is zero for success, else a negative errno status code.
2523  * This call may only be used from a context that may sleep.
2524  *
2525  * Parameters to this routine are always copied using a small buffer;
2526  * portable code should never use this for more than 32 bytes.
2527  * Performance-sensitive or bulk transfer code should instead use
2528  * spi_{async,sync}() calls with dma-safe buffers.
2529  *
2530  * Return: zero on success, else a negative error code.
2531  */
2532 int spi_write_then_read(struct spi_device *spi,
2533                 const void *txbuf, unsigned n_tx,
2534                 void *rxbuf, unsigned n_rx)
2535 {
2536         static DEFINE_MUTEX(lock);
2537
2538         int                     status;
2539         struct spi_message      message;
2540         struct spi_transfer     x[2];
2541         u8                      *local_buf;
2542
2543         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
2544          * copying here, (as a pure convenience thing), but we can
2545          * keep heap costs out of the hot path unless someone else is
2546          * using the pre-allocated buffer or the transfer is too large.
2547          */
2548         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2549                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2550                                     GFP_KERNEL | GFP_DMA);
2551                 if (!local_buf)
2552                         return -ENOMEM;
2553         } else {
2554                 local_buf = buf;
2555         }
2556
2557         spi_message_init(&message);
2558         memset(x, 0, sizeof(x));
2559         if (n_tx) {
2560                 x[0].len = n_tx;
2561                 spi_message_add_tail(&x[0], &message);
2562         }
2563         if (n_rx) {
2564                 x[1].len = n_rx;
2565                 spi_message_add_tail(&x[1], &message);
2566         }
2567
2568         memcpy(local_buf, txbuf, n_tx);
2569         x[0].tx_buf = local_buf;
2570         x[1].rx_buf = local_buf + n_tx;
2571
2572         /* do the i/o */
2573         status = spi_sync(spi, &message);
2574         if (status == 0)
2575                 memcpy(rxbuf, x[1].rx_buf, n_rx);
2576
2577         if (x[0].tx_buf == buf)
2578                 mutex_unlock(&lock);
2579         else
2580                 kfree(local_buf);
2581
2582         return status;
2583 }
2584 EXPORT_SYMBOL_GPL(spi_write_then_read);
2585
2586 /*-------------------------------------------------------------------------*/
2587
2588 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2589 static int __spi_of_device_match(struct device *dev, void *data)
2590 {
2591         return dev->of_node == data;
2592 }
2593
2594 /* must call put_device() when done with returned spi_device device */
2595 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2596 {
2597         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2598                                                 __spi_of_device_match);
2599         return dev ? to_spi_device(dev) : NULL;
2600 }
2601
2602 static int __spi_of_master_match(struct device *dev, const void *data)
2603 {
2604         return dev->of_node == data;
2605 }
2606
2607 /* the spi masters are not using spi_bus, so we find it with another way */
2608 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2609 {
2610         struct device *dev;
2611
2612         dev = class_find_device(&spi_master_class, NULL, node,
2613                                 __spi_of_master_match);
2614         if (!dev)
2615                 return NULL;
2616
2617         /* reference got in class_find_device */
2618         return container_of(dev, struct spi_master, dev);
2619 }
2620
2621 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2622                          void *arg)
2623 {
2624         struct of_reconfig_data *rd = arg;
2625         struct spi_master *master;
2626         struct spi_device *spi;
2627
2628         switch (of_reconfig_get_state_change(action, arg)) {
2629         case OF_RECONFIG_CHANGE_ADD:
2630                 master = of_find_spi_master_by_node(rd->dn->parent);
2631                 if (master == NULL)
2632                         return NOTIFY_OK;       /* not for us */
2633
2634                 spi = of_register_spi_device(master, rd->dn);
2635                 put_device(&master->dev);
2636
2637                 if (IS_ERR(spi)) {
2638                         pr_err("%s: failed to create for '%s'\n",
2639                                         __func__, rd->dn->full_name);
2640                         return notifier_from_errno(PTR_ERR(spi));
2641                 }
2642                 break;
2643
2644         case OF_RECONFIG_CHANGE_REMOVE:
2645                 /* find our device by node */
2646                 spi = of_find_spi_device_by_node(rd->dn);
2647                 if (spi == NULL)
2648                         return NOTIFY_OK;       /* no? not meant for us */
2649
2650                 /* unregister takes one ref away */
2651                 spi_unregister_device(spi);
2652
2653                 /* and put the reference of the find */
2654                 put_device(&spi->dev);
2655                 break;
2656         }
2657
2658         return NOTIFY_OK;
2659 }
2660
2661 static struct notifier_block spi_of_notifier = {
2662         .notifier_call = of_spi_notify,
2663 };
2664 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2665 extern struct notifier_block spi_of_notifier;
2666 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2667
2668 static int __init spi_init(void)
2669 {
2670         int     status;
2671
2672         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2673         if (!buf) {
2674                 status = -ENOMEM;
2675                 goto err0;
2676         }
2677
2678         status = bus_register(&spi_bus_type);
2679         if (status < 0)
2680                 goto err1;
2681
2682         status = class_register(&spi_master_class);
2683         if (status < 0)
2684                 goto err2;
2685
2686         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2687                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2688
2689         return 0;
2690
2691 err2:
2692         bus_unregister(&spi_bus_type);
2693 err1:
2694         kfree(buf);
2695         buf = NULL;
2696 err0:
2697         return status;
2698 }
2699
2700 /* board_info is normally registered in arch_initcall(),
2701  * but even essential drivers wait till later
2702  *
2703  * REVISIT only boardinfo really needs static linking. the rest (device and
2704  * driver registration) _could_ be dynamically linked (modular) ... costs
2705  * include needing to have boardinfo data structures be much more public.
2706  */
2707 postcore_initcall(spi_init);
2708