xref: /openbmc/linux/drivers/spi/spi.c (revision 6aa7de05)
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/property.h>
35 #include <linux/export.h>
36 #include <linux/sched/rt.h>
37 #include <uapi/linux/sched/types.h>
38 #include <linux/delay.h>
39 #include <linux/kthread.h>
40 #include <linux/ioport.h>
41 #include <linux/acpi.h>
42 #include <linux/highmem.h>
43 #include <linux/idr.h>
44 #include <linux/platform_data/x86/apple.h>
45 
46 #define CREATE_TRACE_POINTS
47 #include <trace/events/spi.h>
48 #define SPI_DYN_FIRST_BUS_NUM 0
49 
50 static DEFINE_IDR(spi_master_idr);
51 
52 static void spidev_release(struct device *dev)
53 {
54 	struct spi_device	*spi = to_spi_device(dev);
55 
56 	/* spi controllers may cleanup for released devices */
57 	if (spi->controller->cleanup)
58 		spi->controller->cleanup(spi);
59 
60 	spi_controller_put(spi->controller);
61 	kfree(spi);
62 }
63 
64 static ssize_t
65 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
66 {
67 	const struct spi_device	*spi = to_spi_device(dev);
68 	int len;
69 
70 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
71 	if (len != -ENODEV)
72 		return len;
73 
74 	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
75 }
76 static DEVICE_ATTR_RO(modalias);
77 
78 #define SPI_STATISTICS_ATTRS(field, file)				\
79 static ssize_t spi_controller_##field##_show(struct device *dev,	\
80 					     struct device_attribute *attr, \
81 					     char *buf)			\
82 {									\
83 	struct spi_controller *ctlr = container_of(dev,			\
84 					 struct spi_controller, dev);	\
85 	return spi_statistics_##field##_show(&ctlr->statistics, buf);	\
86 }									\
87 static struct device_attribute dev_attr_spi_controller_##field = {	\
88 	.attr = { .name = file, .mode = 0444 },				\
89 	.show = spi_controller_##field##_show,				\
90 };									\
91 static ssize_t spi_device_##field##_show(struct device *dev,		\
92 					 struct device_attribute *attr,	\
93 					char *buf)			\
94 {									\
95 	struct spi_device *spi = to_spi_device(dev);			\
96 	return spi_statistics_##field##_show(&spi->statistics, buf);	\
97 }									\
98 static struct device_attribute dev_attr_spi_device_##field = {		\
99 	.attr = { .name = file, .mode = 0444 },				\
100 	.show = spi_device_##field##_show,				\
101 }
102 
103 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)	\
104 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
105 					    char *buf)			\
106 {									\
107 	unsigned long flags;						\
108 	ssize_t len;							\
109 	spin_lock_irqsave(&stat->lock, flags);				\
110 	len = sprintf(buf, format_string, stat->field);			\
111 	spin_unlock_irqrestore(&stat->lock, flags);			\
112 	return len;							\
113 }									\
114 SPI_STATISTICS_ATTRS(name, file)
115 
116 #define SPI_STATISTICS_SHOW(field, format_string)			\
117 	SPI_STATISTICS_SHOW_NAME(field, __stringify(field),		\
118 				 field, format_string)
119 
120 SPI_STATISTICS_SHOW(messages, "%lu");
121 SPI_STATISTICS_SHOW(transfers, "%lu");
122 SPI_STATISTICS_SHOW(errors, "%lu");
123 SPI_STATISTICS_SHOW(timedout, "%lu");
124 
125 SPI_STATISTICS_SHOW(spi_sync, "%lu");
126 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
127 SPI_STATISTICS_SHOW(spi_async, "%lu");
128 
129 SPI_STATISTICS_SHOW(bytes, "%llu");
130 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
131 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
132 
133 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)		\
134 	SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,		\
135 				 "transfer_bytes_histo_" number,	\
136 				 transfer_bytes_histo[index],  "%lu")
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
147 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
148 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
149 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
150 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
151 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
152 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
153 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
154 
155 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
156 
157 static struct attribute *spi_dev_attrs[] = {
158 	&dev_attr_modalias.attr,
159 	NULL,
160 };
161 
162 static const struct attribute_group spi_dev_group = {
163 	.attrs  = spi_dev_attrs,
164 };
165 
166 static struct attribute *spi_device_statistics_attrs[] = {
167 	&dev_attr_spi_device_messages.attr,
168 	&dev_attr_spi_device_transfers.attr,
169 	&dev_attr_spi_device_errors.attr,
170 	&dev_attr_spi_device_timedout.attr,
171 	&dev_attr_spi_device_spi_sync.attr,
172 	&dev_attr_spi_device_spi_sync_immediate.attr,
173 	&dev_attr_spi_device_spi_async.attr,
174 	&dev_attr_spi_device_bytes.attr,
175 	&dev_attr_spi_device_bytes_rx.attr,
176 	&dev_attr_spi_device_bytes_tx.attr,
177 	&dev_attr_spi_device_transfer_bytes_histo0.attr,
178 	&dev_attr_spi_device_transfer_bytes_histo1.attr,
179 	&dev_attr_spi_device_transfer_bytes_histo2.attr,
180 	&dev_attr_spi_device_transfer_bytes_histo3.attr,
181 	&dev_attr_spi_device_transfer_bytes_histo4.attr,
182 	&dev_attr_spi_device_transfer_bytes_histo5.attr,
183 	&dev_attr_spi_device_transfer_bytes_histo6.attr,
184 	&dev_attr_spi_device_transfer_bytes_histo7.attr,
185 	&dev_attr_spi_device_transfer_bytes_histo8.attr,
186 	&dev_attr_spi_device_transfer_bytes_histo9.attr,
187 	&dev_attr_spi_device_transfer_bytes_histo10.attr,
188 	&dev_attr_spi_device_transfer_bytes_histo11.attr,
189 	&dev_attr_spi_device_transfer_bytes_histo12.attr,
190 	&dev_attr_spi_device_transfer_bytes_histo13.attr,
191 	&dev_attr_spi_device_transfer_bytes_histo14.attr,
192 	&dev_attr_spi_device_transfer_bytes_histo15.attr,
193 	&dev_attr_spi_device_transfer_bytes_histo16.attr,
194 	&dev_attr_spi_device_transfers_split_maxsize.attr,
195 	NULL,
196 };
197 
198 static const struct attribute_group spi_device_statistics_group = {
199 	.name  = "statistics",
200 	.attrs  = spi_device_statistics_attrs,
201 };
202 
203 static const struct attribute_group *spi_dev_groups[] = {
204 	&spi_dev_group,
205 	&spi_device_statistics_group,
206 	NULL,
207 };
208 
209 static struct attribute *spi_controller_statistics_attrs[] = {
210 	&dev_attr_spi_controller_messages.attr,
211 	&dev_attr_spi_controller_transfers.attr,
212 	&dev_attr_spi_controller_errors.attr,
213 	&dev_attr_spi_controller_timedout.attr,
214 	&dev_attr_spi_controller_spi_sync.attr,
215 	&dev_attr_spi_controller_spi_sync_immediate.attr,
216 	&dev_attr_spi_controller_spi_async.attr,
217 	&dev_attr_spi_controller_bytes.attr,
218 	&dev_attr_spi_controller_bytes_rx.attr,
219 	&dev_attr_spi_controller_bytes_tx.attr,
220 	&dev_attr_spi_controller_transfer_bytes_histo0.attr,
221 	&dev_attr_spi_controller_transfer_bytes_histo1.attr,
222 	&dev_attr_spi_controller_transfer_bytes_histo2.attr,
223 	&dev_attr_spi_controller_transfer_bytes_histo3.attr,
224 	&dev_attr_spi_controller_transfer_bytes_histo4.attr,
225 	&dev_attr_spi_controller_transfer_bytes_histo5.attr,
226 	&dev_attr_spi_controller_transfer_bytes_histo6.attr,
227 	&dev_attr_spi_controller_transfer_bytes_histo7.attr,
228 	&dev_attr_spi_controller_transfer_bytes_histo8.attr,
229 	&dev_attr_spi_controller_transfer_bytes_histo9.attr,
230 	&dev_attr_spi_controller_transfer_bytes_histo10.attr,
231 	&dev_attr_spi_controller_transfer_bytes_histo11.attr,
232 	&dev_attr_spi_controller_transfer_bytes_histo12.attr,
233 	&dev_attr_spi_controller_transfer_bytes_histo13.attr,
234 	&dev_attr_spi_controller_transfer_bytes_histo14.attr,
235 	&dev_attr_spi_controller_transfer_bytes_histo15.attr,
236 	&dev_attr_spi_controller_transfer_bytes_histo16.attr,
237 	&dev_attr_spi_controller_transfers_split_maxsize.attr,
238 	NULL,
239 };
240 
241 static const struct attribute_group spi_controller_statistics_group = {
242 	.name  = "statistics",
243 	.attrs  = spi_controller_statistics_attrs,
244 };
245 
246 static const struct attribute_group *spi_master_groups[] = {
247 	&spi_controller_statistics_group,
248 	NULL,
249 };
250 
251 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
252 				       struct spi_transfer *xfer,
253 				       struct spi_controller *ctlr)
254 {
255 	unsigned long flags;
256 	int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
257 
258 	if (l2len < 0)
259 		l2len = 0;
260 
261 	spin_lock_irqsave(&stats->lock, flags);
262 
263 	stats->transfers++;
264 	stats->transfer_bytes_histo[l2len]++;
265 
266 	stats->bytes += xfer->len;
267 	if ((xfer->tx_buf) &&
268 	    (xfer->tx_buf != ctlr->dummy_tx))
269 		stats->bytes_tx += xfer->len;
270 	if ((xfer->rx_buf) &&
271 	    (xfer->rx_buf != ctlr->dummy_rx))
272 		stats->bytes_rx += xfer->len;
273 
274 	spin_unlock_irqrestore(&stats->lock, flags);
275 }
276 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
277 
278 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
279  * and the sysfs version makes coldplug work too.
280  */
281 
282 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
283 						const struct spi_device *sdev)
284 {
285 	while (id->name[0]) {
286 		if (!strcmp(sdev->modalias, id->name))
287 			return id;
288 		id++;
289 	}
290 	return NULL;
291 }
292 
293 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
294 {
295 	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
296 
297 	return spi_match_id(sdrv->id_table, sdev);
298 }
299 EXPORT_SYMBOL_GPL(spi_get_device_id);
300 
301 static int spi_match_device(struct device *dev, struct device_driver *drv)
302 {
303 	const struct spi_device	*spi = to_spi_device(dev);
304 	const struct spi_driver	*sdrv = to_spi_driver(drv);
305 
306 	/* Attempt an OF style match */
307 	if (of_driver_match_device(dev, drv))
308 		return 1;
309 
310 	/* Then try ACPI */
311 	if (acpi_driver_match_device(dev, drv))
312 		return 1;
313 
314 	if (sdrv->id_table)
315 		return !!spi_match_id(sdrv->id_table, spi);
316 
317 	return strcmp(spi->modalias, drv->name) == 0;
318 }
319 
320 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
321 {
322 	const struct spi_device		*spi = to_spi_device(dev);
323 	int rc;
324 
325 	rc = acpi_device_uevent_modalias(dev, env);
326 	if (rc != -ENODEV)
327 		return rc;
328 
329 	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
330 }
331 
332 struct bus_type spi_bus_type = {
333 	.name		= "spi",
334 	.dev_groups	= spi_dev_groups,
335 	.match		= spi_match_device,
336 	.uevent		= spi_uevent,
337 };
338 EXPORT_SYMBOL_GPL(spi_bus_type);
339 
340 
341 static int spi_drv_probe(struct device *dev)
342 {
343 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
344 	struct spi_device		*spi = to_spi_device(dev);
345 	int ret;
346 
347 	ret = of_clk_set_defaults(dev->of_node, false);
348 	if (ret)
349 		return ret;
350 
351 	if (dev->of_node) {
352 		spi->irq = of_irq_get(dev->of_node, 0);
353 		if (spi->irq == -EPROBE_DEFER)
354 			return -EPROBE_DEFER;
355 		if (spi->irq < 0)
356 			spi->irq = 0;
357 	}
358 
359 	ret = dev_pm_domain_attach(dev, true);
360 	if (ret != -EPROBE_DEFER) {
361 		ret = sdrv->probe(spi);
362 		if (ret)
363 			dev_pm_domain_detach(dev, true);
364 	}
365 
366 	return ret;
367 }
368 
369 static int spi_drv_remove(struct device *dev)
370 {
371 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
372 	int ret;
373 
374 	ret = sdrv->remove(to_spi_device(dev));
375 	dev_pm_domain_detach(dev, true);
376 
377 	return ret;
378 }
379 
380 static void spi_drv_shutdown(struct device *dev)
381 {
382 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
383 
384 	sdrv->shutdown(to_spi_device(dev));
385 }
386 
387 /**
388  * __spi_register_driver - register a SPI driver
389  * @owner: owner module of the driver to register
390  * @sdrv: the driver to register
391  * Context: can sleep
392  *
393  * Return: zero on success, else a negative error code.
394  */
395 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
396 {
397 	sdrv->driver.owner = owner;
398 	sdrv->driver.bus = &spi_bus_type;
399 	if (sdrv->probe)
400 		sdrv->driver.probe = spi_drv_probe;
401 	if (sdrv->remove)
402 		sdrv->driver.remove = spi_drv_remove;
403 	if (sdrv->shutdown)
404 		sdrv->driver.shutdown = spi_drv_shutdown;
405 	return driver_register(&sdrv->driver);
406 }
407 EXPORT_SYMBOL_GPL(__spi_register_driver);
408 
409 /*-------------------------------------------------------------------------*/
410 
411 /* SPI devices should normally not be created by SPI device drivers; that
412  * would make them board-specific.  Similarly with SPI controller drivers.
413  * Device registration normally goes into like arch/.../mach.../board-YYY.c
414  * with other readonly (flashable) information about mainboard devices.
415  */
416 
417 struct boardinfo {
418 	struct list_head	list;
419 	struct spi_board_info	board_info;
420 };
421 
422 static LIST_HEAD(board_list);
423 static LIST_HEAD(spi_controller_list);
424 
425 /*
426  * Used to protect add/del opertion for board_info list and
427  * spi_controller list, and their matching process
428  * also used to protect object of type struct idr
429  */
430 static DEFINE_MUTEX(board_lock);
431 
432 /**
433  * spi_alloc_device - Allocate a new SPI device
434  * @ctlr: Controller to which device is connected
435  * Context: can sleep
436  *
437  * Allows a driver to allocate and initialize a spi_device without
438  * registering it immediately.  This allows a driver to directly
439  * fill the spi_device with device parameters before calling
440  * spi_add_device() on it.
441  *
442  * Caller is responsible to call spi_add_device() on the returned
443  * spi_device structure to add it to the SPI controller.  If the caller
444  * needs to discard the spi_device without adding it, then it should
445  * call spi_dev_put() on it.
446  *
447  * Return: a pointer to the new device, or NULL.
448  */
449 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
450 {
451 	struct spi_device	*spi;
452 
453 	if (!spi_controller_get(ctlr))
454 		return NULL;
455 
456 	spi = kzalloc(sizeof(*spi), GFP_KERNEL);
457 	if (!spi) {
458 		spi_controller_put(ctlr);
459 		return NULL;
460 	}
461 
462 	spi->master = spi->controller = ctlr;
463 	spi->dev.parent = &ctlr->dev;
464 	spi->dev.bus = &spi_bus_type;
465 	spi->dev.release = spidev_release;
466 	spi->cs_gpio = -ENOENT;
467 
468 	spin_lock_init(&spi->statistics.lock);
469 
470 	device_initialize(&spi->dev);
471 	return spi;
472 }
473 EXPORT_SYMBOL_GPL(spi_alloc_device);
474 
475 static void spi_dev_set_name(struct spi_device *spi)
476 {
477 	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
478 
479 	if (adev) {
480 		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
481 		return;
482 	}
483 
484 	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
485 		     spi->chip_select);
486 }
487 
488 static int spi_dev_check(struct device *dev, void *data)
489 {
490 	struct spi_device *spi = to_spi_device(dev);
491 	struct spi_device *new_spi = data;
492 
493 	if (spi->controller == new_spi->controller &&
494 	    spi->chip_select == new_spi->chip_select)
495 		return -EBUSY;
496 	return 0;
497 }
498 
499 /**
500  * spi_add_device - Add spi_device allocated with spi_alloc_device
501  * @spi: spi_device to register
502  *
503  * Companion function to spi_alloc_device.  Devices allocated with
504  * spi_alloc_device can be added onto the spi bus with this function.
505  *
506  * Return: 0 on success; negative errno on failure
507  */
508 int spi_add_device(struct spi_device *spi)
509 {
510 	static DEFINE_MUTEX(spi_add_lock);
511 	struct spi_controller *ctlr = spi->controller;
512 	struct device *dev = ctlr->dev.parent;
513 	int status;
514 
515 	/* Chipselects are numbered 0..max; validate. */
516 	if (spi->chip_select >= ctlr->num_chipselect) {
517 		dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
518 			ctlr->num_chipselect);
519 		return -EINVAL;
520 	}
521 
522 	/* Set the bus ID string */
523 	spi_dev_set_name(spi);
524 
525 	/* We need to make sure there's no other device with this
526 	 * chipselect **BEFORE** we call setup(), else we'll trash
527 	 * its configuration.  Lock against concurrent add() calls.
528 	 */
529 	mutex_lock(&spi_add_lock);
530 
531 	status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
532 	if (status) {
533 		dev_err(dev, "chipselect %d already in use\n",
534 				spi->chip_select);
535 		goto done;
536 	}
537 
538 	if (ctlr->cs_gpios)
539 		spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
540 
541 	/* Drivers may modify this initial i/o setup, but will
542 	 * normally rely on the device being setup.  Devices
543 	 * using SPI_CS_HIGH can't coexist well otherwise...
544 	 */
545 	status = spi_setup(spi);
546 	if (status < 0) {
547 		dev_err(dev, "can't setup %s, status %d\n",
548 				dev_name(&spi->dev), status);
549 		goto done;
550 	}
551 
552 	/* Device may be bound to an active driver when this returns */
553 	status = device_add(&spi->dev);
554 	if (status < 0)
555 		dev_err(dev, "can't add %s, status %d\n",
556 				dev_name(&spi->dev), status);
557 	else
558 		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
559 
560 done:
561 	mutex_unlock(&spi_add_lock);
562 	return status;
563 }
564 EXPORT_SYMBOL_GPL(spi_add_device);
565 
566 /**
567  * spi_new_device - instantiate one new SPI device
568  * @ctlr: Controller to which device is connected
569  * @chip: Describes the SPI device
570  * Context: can sleep
571  *
572  * On typical mainboards, this is purely internal; and it's not needed
573  * after board init creates the hard-wired devices.  Some development
574  * platforms may not be able to use spi_register_board_info though, and
575  * this is exported so that for example a USB or parport based adapter
576  * driver could add devices (which it would learn about out-of-band).
577  *
578  * Return: the new device, or NULL.
579  */
580 struct spi_device *spi_new_device(struct spi_controller *ctlr,
581 				  struct spi_board_info *chip)
582 {
583 	struct spi_device	*proxy;
584 	int			status;
585 
586 	/* NOTE:  caller did any chip->bus_num checks necessary.
587 	 *
588 	 * Also, unless we change the return value convention to use
589 	 * error-or-pointer (not NULL-or-pointer), troubleshootability
590 	 * suggests syslogged diagnostics are best here (ugh).
591 	 */
592 
593 	proxy = spi_alloc_device(ctlr);
594 	if (!proxy)
595 		return NULL;
596 
597 	WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
598 
599 	proxy->chip_select = chip->chip_select;
600 	proxy->max_speed_hz = chip->max_speed_hz;
601 	proxy->mode = chip->mode;
602 	proxy->irq = chip->irq;
603 	strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
604 	proxy->dev.platform_data = (void *) chip->platform_data;
605 	proxy->controller_data = chip->controller_data;
606 	proxy->controller_state = NULL;
607 
608 	if (chip->properties) {
609 		status = device_add_properties(&proxy->dev, chip->properties);
610 		if (status) {
611 			dev_err(&ctlr->dev,
612 				"failed to add properties to '%s': %d\n",
613 				chip->modalias, status);
614 			goto err_dev_put;
615 		}
616 	}
617 
618 	status = spi_add_device(proxy);
619 	if (status < 0)
620 		goto err_remove_props;
621 
622 	return proxy;
623 
624 err_remove_props:
625 	if (chip->properties)
626 		device_remove_properties(&proxy->dev);
627 err_dev_put:
628 	spi_dev_put(proxy);
629 	return NULL;
630 }
631 EXPORT_SYMBOL_GPL(spi_new_device);
632 
633 /**
634  * spi_unregister_device - unregister a single SPI device
635  * @spi: spi_device to unregister
636  *
637  * Start making the passed SPI device vanish. Normally this would be handled
638  * by spi_unregister_controller().
639  */
640 void spi_unregister_device(struct spi_device *spi)
641 {
642 	if (!spi)
643 		return;
644 
645 	if (spi->dev.of_node) {
646 		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
647 		of_node_put(spi->dev.of_node);
648 	}
649 	if (ACPI_COMPANION(&spi->dev))
650 		acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
651 	device_unregister(&spi->dev);
652 }
653 EXPORT_SYMBOL_GPL(spi_unregister_device);
654 
655 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
656 					      struct spi_board_info *bi)
657 {
658 	struct spi_device *dev;
659 
660 	if (ctlr->bus_num != bi->bus_num)
661 		return;
662 
663 	dev = spi_new_device(ctlr, bi);
664 	if (!dev)
665 		dev_err(ctlr->dev.parent, "can't create new device for %s\n",
666 			bi->modalias);
667 }
668 
669 /**
670  * spi_register_board_info - register SPI devices for a given board
671  * @info: array of chip descriptors
672  * @n: how many descriptors are provided
673  * Context: can sleep
674  *
675  * Board-specific early init code calls this (probably during arch_initcall)
676  * with segments of the SPI device table.  Any device nodes are created later,
677  * after the relevant parent SPI controller (bus_num) is defined.  We keep
678  * this table of devices forever, so that reloading a controller driver will
679  * not make Linux forget about these hard-wired devices.
680  *
681  * Other code can also call this, e.g. a particular add-on board might provide
682  * SPI devices through its expansion connector, so code initializing that board
683  * would naturally declare its SPI devices.
684  *
685  * The board info passed can safely be __initdata ... but be careful of
686  * any embedded pointers (platform_data, etc), they're copied as-is.
687  * Device properties are deep-copied though.
688  *
689  * Return: zero on success, else a negative error code.
690  */
691 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
692 {
693 	struct boardinfo *bi;
694 	int i;
695 
696 	if (!n)
697 		return 0;
698 
699 	bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
700 	if (!bi)
701 		return -ENOMEM;
702 
703 	for (i = 0; i < n; i++, bi++, info++) {
704 		struct spi_controller *ctlr;
705 
706 		memcpy(&bi->board_info, info, sizeof(*info));
707 		if (info->properties) {
708 			bi->board_info.properties =
709 					property_entries_dup(info->properties);
710 			if (IS_ERR(bi->board_info.properties))
711 				return PTR_ERR(bi->board_info.properties);
712 		}
713 
714 		mutex_lock(&board_lock);
715 		list_add_tail(&bi->list, &board_list);
716 		list_for_each_entry(ctlr, &spi_controller_list, list)
717 			spi_match_controller_to_boardinfo(ctlr,
718 							  &bi->board_info);
719 		mutex_unlock(&board_lock);
720 	}
721 
722 	return 0;
723 }
724 
725 /*-------------------------------------------------------------------------*/
726 
727 static void spi_set_cs(struct spi_device *spi, bool enable)
728 {
729 	if (spi->mode & SPI_CS_HIGH)
730 		enable = !enable;
731 
732 	if (gpio_is_valid(spi->cs_gpio)) {
733 		gpio_set_value(spi->cs_gpio, !enable);
734 		/* Some SPI masters need both GPIO CS & slave_select */
735 		if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
736 		    spi->controller->set_cs)
737 			spi->controller->set_cs(spi, !enable);
738 	} else if (spi->controller->set_cs) {
739 		spi->controller->set_cs(spi, !enable);
740 	}
741 }
742 
743 #ifdef CONFIG_HAS_DMA
744 static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
745 		       struct sg_table *sgt, void *buf, size_t len,
746 		       enum dma_data_direction dir)
747 {
748 	const bool vmalloced_buf = is_vmalloc_addr(buf);
749 	unsigned int max_seg_size = dma_get_max_seg_size(dev);
750 #ifdef CONFIG_HIGHMEM
751 	const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
752 				(unsigned long)buf < (PKMAP_BASE +
753 					(LAST_PKMAP * PAGE_SIZE)));
754 #else
755 	const bool kmap_buf = false;
756 #endif
757 	int desc_len;
758 	int sgs;
759 	struct page *vm_page;
760 	struct scatterlist *sg;
761 	void *sg_buf;
762 	size_t min;
763 	int i, ret;
764 
765 	if (vmalloced_buf || kmap_buf) {
766 		desc_len = min_t(int, max_seg_size, PAGE_SIZE);
767 		sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
768 	} else if (virt_addr_valid(buf)) {
769 		desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
770 		sgs = DIV_ROUND_UP(len, desc_len);
771 	} else {
772 		return -EINVAL;
773 	}
774 
775 	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
776 	if (ret != 0)
777 		return ret;
778 
779 	sg = &sgt->sgl[0];
780 	for (i = 0; i < sgs; i++) {
781 
782 		if (vmalloced_buf || kmap_buf) {
783 			min = min_t(size_t,
784 				    len, desc_len - offset_in_page(buf));
785 			if (vmalloced_buf)
786 				vm_page = vmalloc_to_page(buf);
787 			else
788 				vm_page = kmap_to_page(buf);
789 			if (!vm_page) {
790 				sg_free_table(sgt);
791 				return -ENOMEM;
792 			}
793 			sg_set_page(sg, vm_page,
794 				    min, offset_in_page(buf));
795 		} else {
796 			min = min_t(size_t, len, desc_len);
797 			sg_buf = buf;
798 			sg_set_buf(sg, sg_buf, min);
799 		}
800 
801 		buf += min;
802 		len -= min;
803 		sg = sg_next(sg);
804 	}
805 
806 	ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
807 	if (!ret)
808 		ret = -ENOMEM;
809 	if (ret < 0) {
810 		sg_free_table(sgt);
811 		return ret;
812 	}
813 
814 	sgt->nents = ret;
815 
816 	return 0;
817 }
818 
819 static void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
820 			  struct sg_table *sgt, enum dma_data_direction dir)
821 {
822 	if (sgt->orig_nents) {
823 		dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
824 		sg_free_table(sgt);
825 	}
826 }
827 
828 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
829 {
830 	struct device *tx_dev, *rx_dev;
831 	struct spi_transfer *xfer;
832 	int ret;
833 
834 	if (!ctlr->can_dma)
835 		return 0;
836 
837 	if (ctlr->dma_tx)
838 		tx_dev = ctlr->dma_tx->device->dev;
839 	else
840 		tx_dev = ctlr->dev.parent;
841 
842 	if (ctlr->dma_rx)
843 		rx_dev = ctlr->dma_rx->device->dev;
844 	else
845 		rx_dev = ctlr->dev.parent;
846 
847 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
848 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
849 			continue;
850 
851 		if (xfer->tx_buf != NULL) {
852 			ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
853 					  (void *)xfer->tx_buf, xfer->len,
854 					  DMA_TO_DEVICE);
855 			if (ret != 0)
856 				return ret;
857 		}
858 
859 		if (xfer->rx_buf != NULL) {
860 			ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
861 					  xfer->rx_buf, xfer->len,
862 					  DMA_FROM_DEVICE);
863 			if (ret != 0) {
864 				spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
865 					      DMA_TO_DEVICE);
866 				return ret;
867 			}
868 		}
869 	}
870 
871 	ctlr->cur_msg_mapped = true;
872 
873 	return 0;
874 }
875 
876 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
877 {
878 	struct spi_transfer *xfer;
879 	struct device *tx_dev, *rx_dev;
880 
881 	if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
882 		return 0;
883 
884 	if (ctlr->dma_tx)
885 		tx_dev = ctlr->dma_tx->device->dev;
886 	else
887 		tx_dev = ctlr->dev.parent;
888 
889 	if (ctlr->dma_rx)
890 		rx_dev = ctlr->dma_rx->device->dev;
891 	else
892 		rx_dev = ctlr->dev.parent;
893 
894 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
895 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
896 			continue;
897 
898 		spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
899 		spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
900 	}
901 
902 	return 0;
903 }
904 #else /* !CONFIG_HAS_DMA */
905 static inline int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
906 			      struct sg_table *sgt, void *buf, size_t len,
907 			      enum dma_data_direction dir)
908 {
909 	return -EINVAL;
910 }
911 
912 static inline void spi_unmap_buf(struct spi_controller *ctlr,
913 				 struct device *dev, struct sg_table *sgt,
914 				 enum dma_data_direction dir)
915 {
916 }
917 
918 static inline int __spi_map_msg(struct spi_controller *ctlr,
919 				struct spi_message *msg)
920 {
921 	return 0;
922 }
923 
924 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
925 				  struct spi_message *msg)
926 {
927 	return 0;
928 }
929 #endif /* !CONFIG_HAS_DMA */
930 
931 static inline int spi_unmap_msg(struct spi_controller *ctlr,
932 				struct spi_message *msg)
933 {
934 	struct spi_transfer *xfer;
935 
936 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
937 		/*
938 		 * Restore the original value of tx_buf or rx_buf if they are
939 		 * NULL.
940 		 */
941 		if (xfer->tx_buf == ctlr->dummy_tx)
942 			xfer->tx_buf = NULL;
943 		if (xfer->rx_buf == ctlr->dummy_rx)
944 			xfer->rx_buf = NULL;
945 	}
946 
947 	return __spi_unmap_msg(ctlr, msg);
948 }
949 
950 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
951 {
952 	struct spi_transfer *xfer;
953 	void *tmp;
954 	unsigned int max_tx, max_rx;
955 
956 	if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
957 		max_tx = 0;
958 		max_rx = 0;
959 
960 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
961 			if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
962 			    !xfer->tx_buf)
963 				max_tx = max(xfer->len, max_tx);
964 			if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
965 			    !xfer->rx_buf)
966 				max_rx = max(xfer->len, max_rx);
967 		}
968 
969 		if (max_tx) {
970 			tmp = krealloc(ctlr->dummy_tx, max_tx,
971 				       GFP_KERNEL | GFP_DMA);
972 			if (!tmp)
973 				return -ENOMEM;
974 			ctlr->dummy_tx = tmp;
975 			memset(tmp, 0, max_tx);
976 		}
977 
978 		if (max_rx) {
979 			tmp = krealloc(ctlr->dummy_rx, max_rx,
980 				       GFP_KERNEL | GFP_DMA);
981 			if (!tmp)
982 				return -ENOMEM;
983 			ctlr->dummy_rx = tmp;
984 		}
985 
986 		if (max_tx || max_rx) {
987 			list_for_each_entry(xfer, &msg->transfers,
988 					    transfer_list) {
989 				if (!xfer->tx_buf)
990 					xfer->tx_buf = ctlr->dummy_tx;
991 				if (!xfer->rx_buf)
992 					xfer->rx_buf = ctlr->dummy_rx;
993 			}
994 		}
995 	}
996 
997 	return __spi_map_msg(ctlr, msg);
998 }
999 
1000 /*
1001  * spi_transfer_one_message - Default implementation of transfer_one_message()
1002  *
1003  * This is a standard implementation of transfer_one_message() for
1004  * drivers which implement a transfer_one() operation.  It provides
1005  * standard handling of delays and chip select management.
1006  */
1007 static int spi_transfer_one_message(struct spi_controller *ctlr,
1008 				    struct spi_message *msg)
1009 {
1010 	struct spi_transfer *xfer;
1011 	bool keep_cs = false;
1012 	int ret = 0;
1013 	unsigned long long ms = 1;
1014 	struct spi_statistics *statm = &ctlr->statistics;
1015 	struct spi_statistics *stats = &msg->spi->statistics;
1016 
1017 	spi_set_cs(msg->spi, true);
1018 
1019 	SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1020 	SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1021 
1022 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1023 		trace_spi_transfer_start(msg, xfer);
1024 
1025 		spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1026 		spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1027 
1028 		if (xfer->tx_buf || xfer->rx_buf) {
1029 			reinit_completion(&ctlr->xfer_completion);
1030 
1031 			ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1032 			if (ret < 0) {
1033 				SPI_STATISTICS_INCREMENT_FIELD(statm,
1034 							       errors);
1035 				SPI_STATISTICS_INCREMENT_FIELD(stats,
1036 							       errors);
1037 				dev_err(&msg->spi->dev,
1038 					"SPI transfer failed: %d\n", ret);
1039 				goto out;
1040 			}
1041 
1042 			if (ret > 0) {
1043 				ret = 0;
1044 				ms = 8LL * 1000LL * xfer->len;
1045 				do_div(ms, xfer->speed_hz);
1046 				ms += ms + 200; /* some tolerance */
1047 
1048 				if (ms > UINT_MAX)
1049 					ms = UINT_MAX;
1050 
1051 				ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1052 								 msecs_to_jiffies(ms));
1053 			}
1054 
1055 			if (ms == 0) {
1056 				SPI_STATISTICS_INCREMENT_FIELD(statm,
1057 							       timedout);
1058 				SPI_STATISTICS_INCREMENT_FIELD(stats,
1059 							       timedout);
1060 				dev_err(&msg->spi->dev,
1061 					"SPI transfer timed out\n");
1062 				msg->status = -ETIMEDOUT;
1063 			}
1064 		} else {
1065 			if (xfer->len)
1066 				dev_err(&msg->spi->dev,
1067 					"Bufferless transfer has length %u\n",
1068 					xfer->len);
1069 		}
1070 
1071 		trace_spi_transfer_stop(msg, xfer);
1072 
1073 		if (msg->status != -EINPROGRESS)
1074 			goto out;
1075 
1076 		if (xfer->delay_usecs) {
1077 			u16 us = xfer->delay_usecs;
1078 
1079 			if (us <= 10)
1080 				udelay(us);
1081 			else
1082 				usleep_range(us, us + DIV_ROUND_UP(us, 10));
1083 		}
1084 
1085 		if (xfer->cs_change) {
1086 			if (list_is_last(&xfer->transfer_list,
1087 					 &msg->transfers)) {
1088 				keep_cs = true;
1089 			} else {
1090 				spi_set_cs(msg->spi, false);
1091 				udelay(10);
1092 				spi_set_cs(msg->spi, true);
1093 			}
1094 		}
1095 
1096 		msg->actual_length += xfer->len;
1097 	}
1098 
1099 out:
1100 	if (ret != 0 || !keep_cs)
1101 		spi_set_cs(msg->spi, false);
1102 
1103 	if (msg->status == -EINPROGRESS)
1104 		msg->status = ret;
1105 
1106 	if (msg->status && ctlr->handle_err)
1107 		ctlr->handle_err(ctlr, msg);
1108 
1109 	spi_res_release(ctlr, msg);
1110 
1111 	spi_finalize_current_message(ctlr);
1112 
1113 	return ret;
1114 }
1115 
1116 /**
1117  * spi_finalize_current_transfer - report completion of a transfer
1118  * @ctlr: the controller reporting completion
1119  *
1120  * Called by SPI drivers using the core transfer_one_message()
1121  * implementation to notify it that the current interrupt driven
1122  * transfer has finished and the next one may be scheduled.
1123  */
1124 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1125 {
1126 	complete(&ctlr->xfer_completion);
1127 }
1128 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1129 
1130 /**
1131  * __spi_pump_messages - function which processes spi message queue
1132  * @ctlr: controller to process queue for
1133  * @in_kthread: true if we are in the context of the message pump thread
1134  *
1135  * This function checks if there is any spi message in the queue that
1136  * needs processing and if so call out to the driver to initialize hardware
1137  * and transfer each message.
1138  *
1139  * Note that it is called both from the kthread itself and also from
1140  * inside spi_sync(); the queue extraction handling at the top of the
1141  * function should deal with this safely.
1142  */
1143 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1144 {
1145 	unsigned long flags;
1146 	bool was_busy = false;
1147 	int ret;
1148 
1149 	/* Lock queue */
1150 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1151 
1152 	/* Make sure we are not already running a message */
1153 	if (ctlr->cur_msg) {
1154 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1155 		return;
1156 	}
1157 
1158 	/* If another context is idling the device then defer */
1159 	if (ctlr->idling) {
1160 		kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1161 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1162 		return;
1163 	}
1164 
1165 	/* Check if the queue is idle */
1166 	if (list_empty(&ctlr->queue) || !ctlr->running) {
1167 		if (!ctlr->busy) {
1168 			spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1169 			return;
1170 		}
1171 
1172 		/* Only do teardown in the thread */
1173 		if (!in_kthread) {
1174 			kthread_queue_work(&ctlr->kworker,
1175 					   &ctlr->pump_messages);
1176 			spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1177 			return;
1178 		}
1179 
1180 		ctlr->busy = false;
1181 		ctlr->idling = true;
1182 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1183 
1184 		kfree(ctlr->dummy_rx);
1185 		ctlr->dummy_rx = NULL;
1186 		kfree(ctlr->dummy_tx);
1187 		ctlr->dummy_tx = NULL;
1188 		if (ctlr->unprepare_transfer_hardware &&
1189 		    ctlr->unprepare_transfer_hardware(ctlr))
1190 			dev_err(&ctlr->dev,
1191 				"failed to unprepare transfer hardware\n");
1192 		if (ctlr->auto_runtime_pm) {
1193 			pm_runtime_mark_last_busy(ctlr->dev.parent);
1194 			pm_runtime_put_autosuspend(ctlr->dev.parent);
1195 		}
1196 		trace_spi_controller_idle(ctlr);
1197 
1198 		spin_lock_irqsave(&ctlr->queue_lock, flags);
1199 		ctlr->idling = false;
1200 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1201 		return;
1202 	}
1203 
1204 	/* Extract head of queue */
1205 	ctlr->cur_msg =
1206 		list_first_entry(&ctlr->queue, struct spi_message, queue);
1207 
1208 	list_del_init(&ctlr->cur_msg->queue);
1209 	if (ctlr->busy)
1210 		was_busy = true;
1211 	else
1212 		ctlr->busy = true;
1213 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1214 
1215 	mutex_lock(&ctlr->io_mutex);
1216 
1217 	if (!was_busy && ctlr->auto_runtime_pm) {
1218 		ret = pm_runtime_get_sync(ctlr->dev.parent);
1219 		if (ret < 0) {
1220 			dev_err(&ctlr->dev, "Failed to power device: %d\n",
1221 				ret);
1222 			mutex_unlock(&ctlr->io_mutex);
1223 			return;
1224 		}
1225 	}
1226 
1227 	if (!was_busy)
1228 		trace_spi_controller_busy(ctlr);
1229 
1230 	if (!was_busy && ctlr->prepare_transfer_hardware) {
1231 		ret = ctlr->prepare_transfer_hardware(ctlr);
1232 		if (ret) {
1233 			dev_err(&ctlr->dev,
1234 				"failed to prepare transfer hardware\n");
1235 
1236 			if (ctlr->auto_runtime_pm)
1237 				pm_runtime_put(ctlr->dev.parent);
1238 			mutex_unlock(&ctlr->io_mutex);
1239 			return;
1240 		}
1241 	}
1242 
1243 	trace_spi_message_start(ctlr->cur_msg);
1244 
1245 	if (ctlr->prepare_message) {
1246 		ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1247 		if (ret) {
1248 			dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1249 				ret);
1250 			ctlr->cur_msg->status = ret;
1251 			spi_finalize_current_message(ctlr);
1252 			goto out;
1253 		}
1254 		ctlr->cur_msg_prepared = true;
1255 	}
1256 
1257 	ret = spi_map_msg(ctlr, ctlr->cur_msg);
1258 	if (ret) {
1259 		ctlr->cur_msg->status = ret;
1260 		spi_finalize_current_message(ctlr);
1261 		goto out;
1262 	}
1263 
1264 	ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1265 	if (ret) {
1266 		dev_err(&ctlr->dev,
1267 			"failed to transfer one message from queue\n");
1268 		goto out;
1269 	}
1270 
1271 out:
1272 	mutex_unlock(&ctlr->io_mutex);
1273 
1274 	/* Prod the scheduler in case transfer_one() was busy waiting */
1275 	if (!ret)
1276 		cond_resched();
1277 }
1278 
1279 /**
1280  * spi_pump_messages - kthread work function which processes spi message queue
1281  * @work: pointer to kthread work struct contained in the controller struct
1282  */
1283 static void spi_pump_messages(struct kthread_work *work)
1284 {
1285 	struct spi_controller *ctlr =
1286 		container_of(work, struct spi_controller, pump_messages);
1287 
1288 	__spi_pump_messages(ctlr, true);
1289 }
1290 
1291 static int spi_init_queue(struct spi_controller *ctlr)
1292 {
1293 	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1294 
1295 	ctlr->running = false;
1296 	ctlr->busy = false;
1297 
1298 	kthread_init_worker(&ctlr->kworker);
1299 	ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1300 					 "%s", dev_name(&ctlr->dev));
1301 	if (IS_ERR(ctlr->kworker_task)) {
1302 		dev_err(&ctlr->dev, "failed to create message pump task\n");
1303 		return PTR_ERR(ctlr->kworker_task);
1304 	}
1305 	kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1306 
1307 	/*
1308 	 * Controller config will indicate if this controller should run the
1309 	 * message pump with high (realtime) priority to reduce the transfer
1310 	 * latency on the bus by minimising the delay between a transfer
1311 	 * request and the scheduling of the message pump thread. Without this
1312 	 * setting the message pump thread will remain at default priority.
1313 	 */
1314 	if (ctlr->rt) {
1315 		dev_info(&ctlr->dev,
1316 			"will run message pump with realtime priority\n");
1317 		sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1318 	}
1319 
1320 	return 0;
1321 }
1322 
1323 /**
1324  * spi_get_next_queued_message() - called by driver to check for queued
1325  * messages
1326  * @ctlr: the controller to check for queued messages
1327  *
1328  * If there are more messages in the queue, the next message is returned from
1329  * this call.
1330  *
1331  * Return: the next message in the queue, else NULL if the queue is empty.
1332  */
1333 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1334 {
1335 	struct spi_message *next;
1336 	unsigned long flags;
1337 
1338 	/* get a pointer to the next message, if any */
1339 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1340 	next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1341 					queue);
1342 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1343 
1344 	return next;
1345 }
1346 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1347 
1348 /**
1349  * spi_finalize_current_message() - the current message is complete
1350  * @ctlr: the controller to return the message to
1351  *
1352  * Called by the driver to notify the core that the message in the front of the
1353  * queue is complete and can be removed from the queue.
1354  */
1355 void spi_finalize_current_message(struct spi_controller *ctlr)
1356 {
1357 	struct spi_message *mesg;
1358 	unsigned long flags;
1359 	int ret;
1360 
1361 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1362 	mesg = ctlr->cur_msg;
1363 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1364 
1365 	spi_unmap_msg(ctlr, mesg);
1366 
1367 	if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1368 		ret = ctlr->unprepare_message(ctlr, mesg);
1369 		if (ret) {
1370 			dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1371 				ret);
1372 		}
1373 	}
1374 
1375 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1376 	ctlr->cur_msg = NULL;
1377 	ctlr->cur_msg_prepared = false;
1378 	kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1379 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1380 
1381 	trace_spi_message_done(mesg);
1382 
1383 	mesg->state = NULL;
1384 	if (mesg->complete)
1385 		mesg->complete(mesg->context);
1386 }
1387 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1388 
1389 static int spi_start_queue(struct spi_controller *ctlr)
1390 {
1391 	unsigned long flags;
1392 
1393 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1394 
1395 	if (ctlr->running || ctlr->busy) {
1396 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1397 		return -EBUSY;
1398 	}
1399 
1400 	ctlr->running = true;
1401 	ctlr->cur_msg = NULL;
1402 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1403 
1404 	kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1405 
1406 	return 0;
1407 }
1408 
1409 static int spi_stop_queue(struct spi_controller *ctlr)
1410 {
1411 	unsigned long flags;
1412 	unsigned limit = 500;
1413 	int ret = 0;
1414 
1415 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1416 
1417 	/*
1418 	 * This is a bit lame, but is optimized for the common execution path.
1419 	 * A wait_queue on the ctlr->busy could be used, but then the common
1420 	 * execution path (pump_messages) would be required to call wake_up or
1421 	 * friends on every SPI message. Do this instead.
1422 	 */
1423 	while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1424 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1425 		usleep_range(10000, 11000);
1426 		spin_lock_irqsave(&ctlr->queue_lock, flags);
1427 	}
1428 
1429 	if (!list_empty(&ctlr->queue) || ctlr->busy)
1430 		ret = -EBUSY;
1431 	else
1432 		ctlr->running = false;
1433 
1434 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1435 
1436 	if (ret) {
1437 		dev_warn(&ctlr->dev, "could not stop message queue\n");
1438 		return ret;
1439 	}
1440 	return ret;
1441 }
1442 
1443 static int spi_destroy_queue(struct spi_controller *ctlr)
1444 {
1445 	int ret;
1446 
1447 	ret = spi_stop_queue(ctlr);
1448 
1449 	/*
1450 	 * kthread_flush_worker will block until all work is done.
1451 	 * If the reason that stop_queue timed out is that the work will never
1452 	 * finish, then it does no good to call flush/stop thread, so
1453 	 * return anyway.
1454 	 */
1455 	if (ret) {
1456 		dev_err(&ctlr->dev, "problem destroying queue\n");
1457 		return ret;
1458 	}
1459 
1460 	kthread_flush_worker(&ctlr->kworker);
1461 	kthread_stop(ctlr->kworker_task);
1462 
1463 	return 0;
1464 }
1465 
1466 static int __spi_queued_transfer(struct spi_device *spi,
1467 				 struct spi_message *msg,
1468 				 bool need_pump)
1469 {
1470 	struct spi_controller *ctlr = spi->controller;
1471 	unsigned long flags;
1472 
1473 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1474 
1475 	if (!ctlr->running) {
1476 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1477 		return -ESHUTDOWN;
1478 	}
1479 	msg->actual_length = 0;
1480 	msg->status = -EINPROGRESS;
1481 
1482 	list_add_tail(&msg->queue, &ctlr->queue);
1483 	if (!ctlr->busy && need_pump)
1484 		kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1485 
1486 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1487 	return 0;
1488 }
1489 
1490 /**
1491  * spi_queued_transfer - transfer function for queued transfers
1492  * @spi: spi device which is requesting transfer
1493  * @msg: spi message which is to handled is queued to driver queue
1494  *
1495  * Return: zero on success, else a negative error code.
1496  */
1497 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1498 {
1499 	return __spi_queued_transfer(spi, msg, true);
1500 }
1501 
1502 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1503 {
1504 	int ret;
1505 
1506 	ctlr->transfer = spi_queued_transfer;
1507 	if (!ctlr->transfer_one_message)
1508 		ctlr->transfer_one_message = spi_transfer_one_message;
1509 
1510 	/* Initialize and start queue */
1511 	ret = spi_init_queue(ctlr);
1512 	if (ret) {
1513 		dev_err(&ctlr->dev, "problem initializing queue\n");
1514 		goto err_init_queue;
1515 	}
1516 	ctlr->queued = true;
1517 	ret = spi_start_queue(ctlr);
1518 	if (ret) {
1519 		dev_err(&ctlr->dev, "problem starting queue\n");
1520 		goto err_start_queue;
1521 	}
1522 
1523 	return 0;
1524 
1525 err_start_queue:
1526 	spi_destroy_queue(ctlr);
1527 err_init_queue:
1528 	return ret;
1529 }
1530 
1531 /*-------------------------------------------------------------------------*/
1532 
1533 #if defined(CONFIG_OF)
1534 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1535 			   struct device_node *nc)
1536 {
1537 	u32 value;
1538 	int rc;
1539 
1540 	/* Mode (clock phase/polarity/etc.) */
1541 	if (of_property_read_bool(nc, "spi-cpha"))
1542 		spi->mode |= SPI_CPHA;
1543 	if (of_property_read_bool(nc, "spi-cpol"))
1544 		spi->mode |= SPI_CPOL;
1545 	if (of_property_read_bool(nc, "spi-cs-high"))
1546 		spi->mode |= SPI_CS_HIGH;
1547 	if (of_property_read_bool(nc, "spi-3wire"))
1548 		spi->mode |= SPI_3WIRE;
1549 	if (of_property_read_bool(nc, "spi-lsb-first"))
1550 		spi->mode |= SPI_LSB_FIRST;
1551 
1552 	/* Device DUAL/QUAD mode */
1553 	if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1554 		switch (value) {
1555 		case 1:
1556 			break;
1557 		case 2:
1558 			spi->mode |= SPI_TX_DUAL;
1559 			break;
1560 		case 4:
1561 			spi->mode |= SPI_TX_QUAD;
1562 			break;
1563 		default:
1564 			dev_warn(&ctlr->dev,
1565 				"spi-tx-bus-width %d not supported\n",
1566 				value);
1567 			break;
1568 		}
1569 	}
1570 
1571 	if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1572 		switch (value) {
1573 		case 1:
1574 			break;
1575 		case 2:
1576 			spi->mode |= SPI_RX_DUAL;
1577 			break;
1578 		case 4:
1579 			spi->mode |= SPI_RX_QUAD;
1580 			break;
1581 		default:
1582 			dev_warn(&ctlr->dev,
1583 				"spi-rx-bus-width %d not supported\n",
1584 				value);
1585 			break;
1586 		}
1587 	}
1588 
1589 	if (spi_controller_is_slave(ctlr)) {
1590 		if (strcmp(nc->name, "slave")) {
1591 			dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1592 				nc);
1593 			return -EINVAL;
1594 		}
1595 		return 0;
1596 	}
1597 
1598 	/* Device address */
1599 	rc = of_property_read_u32(nc, "reg", &value);
1600 	if (rc) {
1601 		dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1602 			nc, rc);
1603 		return rc;
1604 	}
1605 	spi->chip_select = value;
1606 
1607 	/* Device speed */
1608 	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1609 	if (rc) {
1610 		dev_err(&ctlr->dev,
1611 			"%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1612 		return rc;
1613 	}
1614 	spi->max_speed_hz = value;
1615 
1616 	return 0;
1617 }
1618 
1619 static struct spi_device *
1620 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1621 {
1622 	struct spi_device *spi;
1623 	int rc;
1624 
1625 	/* Alloc an spi_device */
1626 	spi = spi_alloc_device(ctlr);
1627 	if (!spi) {
1628 		dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1629 		rc = -ENOMEM;
1630 		goto err_out;
1631 	}
1632 
1633 	/* Select device driver */
1634 	rc = of_modalias_node(nc, spi->modalias,
1635 				sizeof(spi->modalias));
1636 	if (rc < 0) {
1637 		dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1638 		goto err_out;
1639 	}
1640 
1641 	rc = of_spi_parse_dt(ctlr, spi, nc);
1642 	if (rc)
1643 		goto err_out;
1644 
1645 	/* Store a pointer to the node in the device structure */
1646 	of_node_get(nc);
1647 	spi->dev.of_node = nc;
1648 
1649 	/* Register the new device */
1650 	rc = spi_add_device(spi);
1651 	if (rc) {
1652 		dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1653 		goto err_of_node_put;
1654 	}
1655 
1656 	return spi;
1657 
1658 err_of_node_put:
1659 	of_node_put(nc);
1660 err_out:
1661 	spi_dev_put(spi);
1662 	return ERR_PTR(rc);
1663 }
1664 
1665 /**
1666  * of_register_spi_devices() - Register child devices onto the SPI bus
1667  * @ctlr:	Pointer to spi_controller device
1668  *
1669  * Registers an spi_device for each child node of controller node which
1670  * represents a valid SPI slave.
1671  */
1672 static void of_register_spi_devices(struct spi_controller *ctlr)
1673 {
1674 	struct spi_device *spi;
1675 	struct device_node *nc;
1676 
1677 	if (!ctlr->dev.of_node)
1678 		return;
1679 
1680 	for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1681 		if (of_node_test_and_set_flag(nc, OF_POPULATED))
1682 			continue;
1683 		spi = of_register_spi_device(ctlr, nc);
1684 		if (IS_ERR(spi)) {
1685 			dev_warn(&ctlr->dev,
1686 				 "Failed to create SPI device for %pOF\n", nc);
1687 			of_node_clear_flag(nc, OF_POPULATED);
1688 		}
1689 	}
1690 }
1691 #else
1692 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1693 #endif
1694 
1695 #ifdef CONFIG_ACPI
1696 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1697 {
1698 	struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1699 	const union acpi_object *obj;
1700 
1701 	if (!x86_apple_machine)
1702 		return;
1703 
1704 	if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1705 	    && obj->buffer.length >= 4)
1706 		spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1707 
1708 	if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1709 	    && obj->buffer.length == 8)
1710 		spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1711 
1712 	if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1713 	    && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1714 		spi->mode |= SPI_LSB_FIRST;
1715 
1716 	if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1717 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1718 		spi->mode |= SPI_CPOL;
1719 
1720 	if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1721 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1722 		spi->mode |= SPI_CPHA;
1723 }
1724 
1725 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1726 {
1727 	struct spi_device *spi = data;
1728 	struct spi_controller *ctlr = spi->controller;
1729 
1730 	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1731 		struct acpi_resource_spi_serialbus *sb;
1732 
1733 		sb = &ares->data.spi_serial_bus;
1734 		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1735 			/*
1736 			 * ACPI DeviceSelection numbering is handled by the
1737 			 * host controller driver in Windows and can vary
1738 			 * from driver to driver. In Linux we always expect
1739 			 * 0 .. max - 1 so we need to ask the driver to
1740 			 * translate between the two schemes.
1741 			 */
1742 			if (ctlr->fw_translate_cs) {
1743 				int cs = ctlr->fw_translate_cs(ctlr,
1744 						sb->device_selection);
1745 				if (cs < 0)
1746 					return cs;
1747 				spi->chip_select = cs;
1748 			} else {
1749 				spi->chip_select = sb->device_selection;
1750 			}
1751 
1752 			spi->max_speed_hz = sb->connection_speed;
1753 
1754 			if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1755 				spi->mode |= SPI_CPHA;
1756 			if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1757 				spi->mode |= SPI_CPOL;
1758 			if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1759 				spi->mode |= SPI_CS_HIGH;
1760 		}
1761 	} else if (spi->irq < 0) {
1762 		struct resource r;
1763 
1764 		if (acpi_dev_resource_interrupt(ares, 0, &r))
1765 			spi->irq = r.start;
1766 	}
1767 
1768 	/* Always tell the ACPI core to skip this resource */
1769 	return 1;
1770 }
1771 
1772 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1773 					    struct acpi_device *adev)
1774 {
1775 	struct list_head resource_list;
1776 	struct spi_device *spi;
1777 	int ret;
1778 
1779 	if (acpi_bus_get_status(adev) || !adev->status.present ||
1780 	    acpi_device_enumerated(adev))
1781 		return AE_OK;
1782 
1783 	spi = spi_alloc_device(ctlr);
1784 	if (!spi) {
1785 		dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1786 			dev_name(&adev->dev));
1787 		return AE_NO_MEMORY;
1788 	}
1789 
1790 	ACPI_COMPANION_SET(&spi->dev, adev);
1791 	spi->irq = -1;
1792 
1793 	INIT_LIST_HEAD(&resource_list);
1794 	ret = acpi_dev_get_resources(adev, &resource_list,
1795 				     acpi_spi_add_resource, spi);
1796 	acpi_dev_free_resource_list(&resource_list);
1797 
1798 	acpi_spi_parse_apple_properties(spi);
1799 
1800 	if (ret < 0 || !spi->max_speed_hz) {
1801 		spi_dev_put(spi);
1802 		return AE_OK;
1803 	}
1804 
1805 	acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1806 			  sizeof(spi->modalias));
1807 
1808 	if (spi->irq < 0)
1809 		spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1810 
1811 	acpi_device_set_enumerated(adev);
1812 
1813 	adev->power.flags.ignore_parent = true;
1814 	if (spi_add_device(spi)) {
1815 		adev->power.flags.ignore_parent = false;
1816 		dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1817 			dev_name(&adev->dev));
1818 		spi_dev_put(spi);
1819 	}
1820 
1821 	return AE_OK;
1822 }
1823 
1824 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1825 				       void *data, void **return_value)
1826 {
1827 	struct spi_controller *ctlr = data;
1828 	struct acpi_device *adev;
1829 
1830 	if (acpi_bus_get_device(handle, &adev))
1831 		return AE_OK;
1832 
1833 	return acpi_register_spi_device(ctlr, adev);
1834 }
1835 
1836 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1837 {
1838 	acpi_status status;
1839 	acpi_handle handle;
1840 
1841 	handle = ACPI_HANDLE(ctlr->dev.parent);
1842 	if (!handle)
1843 		return;
1844 
1845 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1846 				     acpi_spi_add_device, NULL, ctlr, NULL);
1847 	if (ACPI_FAILURE(status))
1848 		dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1849 }
1850 #else
1851 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1852 #endif /* CONFIG_ACPI */
1853 
1854 static void spi_controller_release(struct device *dev)
1855 {
1856 	struct spi_controller *ctlr;
1857 
1858 	ctlr = container_of(dev, struct spi_controller, dev);
1859 	kfree(ctlr);
1860 }
1861 
1862 static struct class spi_master_class = {
1863 	.name		= "spi_master",
1864 	.owner		= THIS_MODULE,
1865 	.dev_release	= spi_controller_release,
1866 	.dev_groups	= spi_master_groups,
1867 };
1868 
1869 #ifdef CONFIG_SPI_SLAVE
1870 /**
1871  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1872  *		     controller
1873  * @spi: device used for the current transfer
1874  */
1875 int spi_slave_abort(struct spi_device *spi)
1876 {
1877 	struct spi_controller *ctlr = spi->controller;
1878 
1879 	if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1880 		return ctlr->slave_abort(ctlr);
1881 
1882 	return -ENOTSUPP;
1883 }
1884 EXPORT_SYMBOL_GPL(spi_slave_abort);
1885 
1886 static int match_true(struct device *dev, void *data)
1887 {
1888 	return 1;
1889 }
1890 
1891 static ssize_t spi_slave_show(struct device *dev,
1892 			      struct device_attribute *attr, char *buf)
1893 {
1894 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1895 						   dev);
1896 	struct device *child;
1897 
1898 	child = device_find_child(&ctlr->dev, NULL, match_true);
1899 	return sprintf(buf, "%s\n",
1900 		       child ? to_spi_device(child)->modalias : NULL);
1901 }
1902 
1903 static ssize_t spi_slave_store(struct device *dev,
1904 			       struct device_attribute *attr, const char *buf,
1905 			       size_t count)
1906 {
1907 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1908 						   dev);
1909 	struct spi_device *spi;
1910 	struct device *child;
1911 	char name[32];
1912 	int rc;
1913 
1914 	rc = sscanf(buf, "%31s", name);
1915 	if (rc != 1 || !name[0])
1916 		return -EINVAL;
1917 
1918 	child = device_find_child(&ctlr->dev, NULL, match_true);
1919 	if (child) {
1920 		/* Remove registered slave */
1921 		device_unregister(child);
1922 		put_device(child);
1923 	}
1924 
1925 	if (strcmp(name, "(null)")) {
1926 		/* Register new slave */
1927 		spi = spi_alloc_device(ctlr);
1928 		if (!spi)
1929 			return -ENOMEM;
1930 
1931 		strlcpy(spi->modalias, name, sizeof(spi->modalias));
1932 
1933 		rc = spi_add_device(spi);
1934 		if (rc) {
1935 			spi_dev_put(spi);
1936 			return rc;
1937 		}
1938 	}
1939 
1940 	return count;
1941 }
1942 
1943 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
1944 
1945 static struct attribute *spi_slave_attrs[] = {
1946 	&dev_attr_slave.attr,
1947 	NULL,
1948 };
1949 
1950 static const struct attribute_group spi_slave_group = {
1951 	.attrs = spi_slave_attrs,
1952 };
1953 
1954 static const struct attribute_group *spi_slave_groups[] = {
1955 	&spi_controller_statistics_group,
1956 	&spi_slave_group,
1957 	NULL,
1958 };
1959 
1960 static struct class spi_slave_class = {
1961 	.name		= "spi_slave",
1962 	.owner		= THIS_MODULE,
1963 	.dev_release	= spi_controller_release,
1964 	.dev_groups	= spi_slave_groups,
1965 };
1966 #else
1967 extern struct class spi_slave_class;	/* dummy */
1968 #endif
1969 
1970 /**
1971  * __spi_alloc_controller - allocate an SPI master or slave controller
1972  * @dev: the controller, possibly using the platform_bus
1973  * @size: how much zeroed driver-private data to allocate; the pointer to this
1974  *	memory is in the driver_data field of the returned device,
1975  *	accessible with spi_controller_get_devdata().
1976  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
1977  *	slave (true) controller
1978  * Context: can sleep
1979  *
1980  * This call is used only by SPI controller drivers, which are the
1981  * only ones directly touching chip registers.  It's how they allocate
1982  * an spi_controller structure, prior to calling spi_register_controller().
1983  *
1984  * This must be called from context that can sleep.
1985  *
1986  * The caller is responsible for assigning the bus number and initializing the
1987  * controller's methods before calling spi_register_controller(); and (after
1988  * errors adding the device) calling spi_controller_put() to prevent a memory
1989  * leak.
1990  *
1991  * Return: the SPI controller structure on success, else NULL.
1992  */
1993 struct spi_controller *__spi_alloc_controller(struct device *dev,
1994 					      unsigned int size, bool slave)
1995 {
1996 	struct spi_controller	*ctlr;
1997 
1998 	if (!dev)
1999 		return NULL;
2000 
2001 	ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2002 	if (!ctlr)
2003 		return NULL;
2004 
2005 	device_initialize(&ctlr->dev);
2006 	ctlr->bus_num = -1;
2007 	ctlr->num_chipselect = 1;
2008 	ctlr->slave = slave;
2009 	if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2010 		ctlr->dev.class = &spi_slave_class;
2011 	else
2012 		ctlr->dev.class = &spi_master_class;
2013 	ctlr->dev.parent = dev;
2014 	pm_suspend_ignore_children(&ctlr->dev, true);
2015 	spi_controller_set_devdata(ctlr, &ctlr[1]);
2016 
2017 	return ctlr;
2018 }
2019 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2020 
2021 #ifdef CONFIG_OF
2022 static int of_spi_register_master(struct spi_controller *ctlr)
2023 {
2024 	int nb, i, *cs;
2025 	struct device_node *np = ctlr->dev.of_node;
2026 
2027 	if (!np)
2028 		return 0;
2029 
2030 	nb = of_gpio_named_count(np, "cs-gpios");
2031 	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2032 
2033 	/* Return error only for an incorrectly formed cs-gpios property */
2034 	if (nb == 0 || nb == -ENOENT)
2035 		return 0;
2036 	else if (nb < 0)
2037 		return nb;
2038 
2039 	cs = devm_kzalloc(&ctlr->dev, sizeof(int) * ctlr->num_chipselect,
2040 			  GFP_KERNEL);
2041 	ctlr->cs_gpios = cs;
2042 
2043 	if (!ctlr->cs_gpios)
2044 		return -ENOMEM;
2045 
2046 	for (i = 0; i < ctlr->num_chipselect; i++)
2047 		cs[i] = -ENOENT;
2048 
2049 	for (i = 0; i < nb; i++)
2050 		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2051 
2052 	return 0;
2053 }
2054 #else
2055 static int of_spi_register_master(struct spi_controller *ctlr)
2056 {
2057 	return 0;
2058 }
2059 #endif
2060 
2061 /**
2062  * spi_register_controller - register SPI master or slave controller
2063  * @ctlr: initialized master, originally from spi_alloc_master() or
2064  *	spi_alloc_slave()
2065  * Context: can sleep
2066  *
2067  * SPI controllers connect to their drivers using some non-SPI bus,
2068  * such as the platform bus.  The final stage of probe() in that code
2069  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2070  *
2071  * SPI controllers use board specific (often SOC specific) bus numbers,
2072  * and board-specific addressing for SPI devices combines those numbers
2073  * with chip select numbers.  Since SPI does not directly support dynamic
2074  * device identification, boards need configuration tables telling which
2075  * chip is at which address.
2076  *
2077  * This must be called from context that can sleep.  It returns zero on
2078  * success, else a negative error code (dropping the controller's refcount).
2079  * After a successful return, the caller is responsible for calling
2080  * spi_unregister_controller().
2081  *
2082  * Return: zero on success, else a negative error code.
2083  */
2084 int spi_register_controller(struct spi_controller *ctlr)
2085 {
2086 	struct device		*dev = ctlr->dev.parent;
2087 	struct boardinfo	*bi;
2088 	int			status = -ENODEV;
2089 	int			id;
2090 
2091 	if (!dev)
2092 		return -ENODEV;
2093 
2094 	if (!spi_controller_is_slave(ctlr)) {
2095 		status = of_spi_register_master(ctlr);
2096 		if (status)
2097 			return status;
2098 	}
2099 
2100 	/* even if it's just one always-selected device, there must
2101 	 * be at least one chipselect
2102 	 */
2103 	if (ctlr->num_chipselect == 0)
2104 		return -EINVAL;
2105 	/* allocate dynamic bus number using Linux idr */
2106 	if ((ctlr->bus_num < 0) && ctlr->dev.of_node) {
2107 		id = of_alias_get_id(ctlr->dev.of_node, "spi");
2108 		if (id >= 0) {
2109 			ctlr->bus_num = id;
2110 			mutex_lock(&board_lock);
2111 			id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2112 				       ctlr->bus_num + 1, GFP_KERNEL);
2113 			mutex_unlock(&board_lock);
2114 			if (WARN(id < 0, "couldn't get idr"))
2115 				return id == -ENOSPC ? -EBUSY : id;
2116 		}
2117 	}
2118 	if (ctlr->bus_num < 0) {
2119 		mutex_lock(&board_lock);
2120 		id = idr_alloc(&spi_master_idr, ctlr, SPI_DYN_FIRST_BUS_NUM, 0,
2121 			       GFP_KERNEL);
2122 		mutex_unlock(&board_lock);
2123 		if (WARN(id < 0, "couldn't get idr"))
2124 			return id;
2125 		ctlr->bus_num = id;
2126 	}
2127 	INIT_LIST_HEAD(&ctlr->queue);
2128 	spin_lock_init(&ctlr->queue_lock);
2129 	spin_lock_init(&ctlr->bus_lock_spinlock);
2130 	mutex_init(&ctlr->bus_lock_mutex);
2131 	mutex_init(&ctlr->io_mutex);
2132 	ctlr->bus_lock_flag = 0;
2133 	init_completion(&ctlr->xfer_completion);
2134 	if (!ctlr->max_dma_len)
2135 		ctlr->max_dma_len = INT_MAX;
2136 
2137 	/* register the device, then userspace will see it.
2138 	 * registration fails if the bus ID is in use.
2139 	 */
2140 	dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2141 	status = device_add(&ctlr->dev);
2142 	if (status < 0) {
2143 		/* free bus id */
2144 		mutex_lock(&board_lock);
2145 		idr_remove(&spi_master_idr, ctlr->bus_num);
2146 		mutex_unlock(&board_lock);
2147 		goto done;
2148 	}
2149 	dev_dbg(dev, "registered %s %s\n",
2150 			spi_controller_is_slave(ctlr) ? "slave" : "master",
2151 			dev_name(&ctlr->dev));
2152 
2153 	/* If we're using a queued driver, start the queue */
2154 	if (ctlr->transfer)
2155 		dev_info(dev, "controller is unqueued, this is deprecated\n");
2156 	else {
2157 		status = spi_controller_initialize_queue(ctlr);
2158 		if (status) {
2159 			device_del(&ctlr->dev);
2160 			/* free bus id */
2161 			mutex_lock(&board_lock);
2162 			idr_remove(&spi_master_idr, ctlr->bus_num);
2163 			mutex_unlock(&board_lock);
2164 			goto done;
2165 		}
2166 	}
2167 	/* add statistics */
2168 	spin_lock_init(&ctlr->statistics.lock);
2169 
2170 	mutex_lock(&board_lock);
2171 	list_add_tail(&ctlr->list, &spi_controller_list);
2172 	list_for_each_entry(bi, &board_list, list)
2173 		spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2174 	mutex_unlock(&board_lock);
2175 
2176 	/* Register devices from the device tree and ACPI */
2177 	of_register_spi_devices(ctlr);
2178 	acpi_register_spi_devices(ctlr);
2179 done:
2180 	return status;
2181 }
2182 EXPORT_SYMBOL_GPL(spi_register_controller);
2183 
2184 static void devm_spi_unregister(struct device *dev, void *res)
2185 {
2186 	spi_unregister_controller(*(struct spi_controller **)res);
2187 }
2188 
2189 /**
2190  * devm_spi_register_controller - register managed SPI master or slave
2191  *	controller
2192  * @dev:    device managing SPI controller
2193  * @ctlr: initialized controller, originally from spi_alloc_master() or
2194  *	spi_alloc_slave()
2195  * Context: can sleep
2196  *
2197  * Register a SPI device as with spi_register_controller() which will
2198  * automatically be unregister
2199  *
2200  * Return: zero on success, else a negative error code.
2201  */
2202 int devm_spi_register_controller(struct device *dev,
2203 				 struct spi_controller *ctlr)
2204 {
2205 	struct spi_controller **ptr;
2206 	int ret;
2207 
2208 	ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2209 	if (!ptr)
2210 		return -ENOMEM;
2211 
2212 	ret = spi_register_controller(ctlr);
2213 	if (!ret) {
2214 		*ptr = ctlr;
2215 		devres_add(dev, ptr);
2216 	} else {
2217 		devres_free(ptr);
2218 	}
2219 
2220 	return ret;
2221 }
2222 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2223 
2224 static int __unregister(struct device *dev, void *null)
2225 {
2226 	spi_unregister_device(to_spi_device(dev));
2227 	return 0;
2228 }
2229 
2230 /**
2231  * spi_unregister_controller - unregister SPI master or slave controller
2232  * @ctlr: the controller being unregistered
2233  * Context: can sleep
2234  *
2235  * This call is used only by SPI controller drivers, which are the
2236  * only ones directly touching chip registers.
2237  *
2238  * This must be called from context that can sleep.
2239  */
2240 void spi_unregister_controller(struct spi_controller *ctlr)
2241 {
2242 	struct spi_controller *found;
2243 	int dummy;
2244 
2245 	/* First make sure that this controller was ever added */
2246 	mutex_lock(&board_lock);
2247 	found = idr_find(&spi_master_idr, ctlr->bus_num);
2248 	mutex_unlock(&board_lock);
2249 	if (found != ctlr) {
2250 		dev_dbg(&ctlr->dev,
2251 			"attempting to delete unregistered controller [%s]\n",
2252 			dev_name(&ctlr->dev));
2253 		return;
2254 	}
2255 	if (ctlr->queued) {
2256 		if (spi_destroy_queue(ctlr))
2257 			dev_err(&ctlr->dev, "queue remove failed\n");
2258 	}
2259 	mutex_lock(&board_lock);
2260 	list_del(&ctlr->list);
2261 	mutex_unlock(&board_lock);
2262 
2263 	dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2264 	device_unregister(&ctlr->dev);
2265 	/* free bus id */
2266 	mutex_lock(&board_lock);
2267 	idr_remove(&spi_master_idr, ctlr->bus_num);
2268 	mutex_unlock(&board_lock);
2269 }
2270 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2271 
2272 int spi_controller_suspend(struct spi_controller *ctlr)
2273 {
2274 	int ret;
2275 
2276 	/* Basically no-ops for non-queued controllers */
2277 	if (!ctlr->queued)
2278 		return 0;
2279 
2280 	ret = spi_stop_queue(ctlr);
2281 	if (ret)
2282 		dev_err(&ctlr->dev, "queue stop failed\n");
2283 
2284 	return ret;
2285 }
2286 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2287 
2288 int spi_controller_resume(struct spi_controller *ctlr)
2289 {
2290 	int ret;
2291 
2292 	if (!ctlr->queued)
2293 		return 0;
2294 
2295 	ret = spi_start_queue(ctlr);
2296 	if (ret)
2297 		dev_err(&ctlr->dev, "queue restart failed\n");
2298 
2299 	return ret;
2300 }
2301 EXPORT_SYMBOL_GPL(spi_controller_resume);
2302 
2303 static int __spi_controller_match(struct device *dev, const void *data)
2304 {
2305 	struct spi_controller *ctlr;
2306 	const u16 *bus_num = data;
2307 
2308 	ctlr = container_of(dev, struct spi_controller, dev);
2309 	return ctlr->bus_num == *bus_num;
2310 }
2311 
2312 /**
2313  * spi_busnum_to_master - look up master associated with bus_num
2314  * @bus_num: the master's bus number
2315  * Context: can sleep
2316  *
2317  * This call may be used with devices that are registered after
2318  * arch init time.  It returns a refcounted pointer to the relevant
2319  * spi_controller (which the caller must release), or NULL if there is
2320  * no such master registered.
2321  *
2322  * Return: the SPI master structure on success, else NULL.
2323  */
2324 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2325 {
2326 	struct device		*dev;
2327 	struct spi_controller	*ctlr = NULL;
2328 
2329 	dev = class_find_device(&spi_master_class, NULL, &bus_num,
2330 				__spi_controller_match);
2331 	if (dev)
2332 		ctlr = container_of(dev, struct spi_controller, dev);
2333 	/* reference got in class_find_device */
2334 	return ctlr;
2335 }
2336 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2337 
2338 /*-------------------------------------------------------------------------*/
2339 
2340 /* Core methods for SPI resource management */
2341 
2342 /**
2343  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2344  *                 during the processing of a spi_message while using
2345  *                 spi_transfer_one
2346  * @spi:     the spi device for which we allocate memory
2347  * @release: the release code to execute for this resource
2348  * @size:    size to alloc and return
2349  * @gfp:     GFP allocation flags
2350  *
2351  * Return: the pointer to the allocated data
2352  *
2353  * This may get enhanced in the future to allocate from a memory pool
2354  * of the @spi_device or @spi_controller to avoid repeated allocations.
2355  */
2356 void *spi_res_alloc(struct spi_device *spi,
2357 		    spi_res_release_t release,
2358 		    size_t size, gfp_t gfp)
2359 {
2360 	struct spi_res *sres;
2361 
2362 	sres = kzalloc(sizeof(*sres) + size, gfp);
2363 	if (!sres)
2364 		return NULL;
2365 
2366 	INIT_LIST_HEAD(&sres->entry);
2367 	sres->release = release;
2368 
2369 	return sres->data;
2370 }
2371 EXPORT_SYMBOL_GPL(spi_res_alloc);
2372 
2373 /**
2374  * spi_res_free - free an spi resource
2375  * @res: pointer to the custom data of a resource
2376  *
2377  */
2378 void spi_res_free(void *res)
2379 {
2380 	struct spi_res *sres = container_of(res, struct spi_res, data);
2381 
2382 	if (!res)
2383 		return;
2384 
2385 	WARN_ON(!list_empty(&sres->entry));
2386 	kfree(sres);
2387 }
2388 EXPORT_SYMBOL_GPL(spi_res_free);
2389 
2390 /**
2391  * spi_res_add - add a spi_res to the spi_message
2392  * @message: the spi message
2393  * @res:     the spi_resource
2394  */
2395 void spi_res_add(struct spi_message *message, void *res)
2396 {
2397 	struct spi_res *sres = container_of(res, struct spi_res, data);
2398 
2399 	WARN_ON(!list_empty(&sres->entry));
2400 	list_add_tail(&sres->entry, &message->resources);
2401 }
2402 EXPORT_SYMBOL_GPL(spi_res_add);
2403 
2404 /**
2405  * spi_res_release - release all spi resources for this message
2406  * @ctlr:  the @spi_controller
2407  * @message: the @spi_message
2408  */
2409 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2410 {
2411 	struct spi_res *res;
2412 
2413 	while (!list_empty(&message->resources)) {
2414 		res = list_last_entry(&message->resources,
2415 				      struct spi_res, entry);
2416 
2417 		if (res->release)
2418 			res->release(ctlr, message, res->data);
2419 
2420 		list_del(&res->entry);
2421 
2422 		kfree(res);
2423 	}
2424 }
2425 EXPORT_SYMBOL_GPL(spi_res_release);
2426 
2427 /*-------------------------------------------------------------------------*/
2428 
2429 /* Core methods for spi_message alterations */
2430 
2431 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2432 					    struct spi_message *msg,
2433 					    void *res)
2434 {
2435 	struct spi_replaced_transfers *rxfer = res;
2436 	size_t i;
2437 
2438 	/* call extra callback if requested */
2439 	if (rxfer->release)
2440 		rxfer->release(ctlr, msg, res);
2441 
2442 	/* insert replaced transfers back into the message */
2443 	list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2444 
2445 	/* remove the formerly inserted entries */
2446 	for (i = 0; i < rxfer->inserted; i++)
2447 		list_del(&rxfer->inserted_transfers[i].transfer_list);
2448 }
2449 
2450 /**
2451  * spi_replace_transfers - replace transfers with several transfers
2452  *                         and register change with spi_message.resources
2453  * @msg:           the spi_message we work upon
2454  * @xfer_first:    the first spi_transfer we want to replace
2455  * @remove:        number of transfers to remove
2456  * @insert:        the number of transfers we want to insert instead
2457  * @release:       extra release code necessary in some circumstances
2458  * @extradatasize: extra data to allocate (with alignment guarantees
2459  *                 of struct @spi_transfer)
2460  * @gfp:           gfp flags
2461  *
2462  * Returns: pointer to @spi_replaced_transfers,
2463  *          PTR_ERR(...) in case of errors.
2464  */
2465 struct spi_replaced_transfers *spi_replace_transfers(
2466 	struct spi_message *msg,
2467 	struct spi_transfer *xfer_first,
2468 	size_t remove,
2469 	size_t insert,
2470 	spi_replaced_release_t release,
2471 	size_t extradatasize,
2472 	gfp_t gfp)
2473 {
2474 	struct spi_replaced_transfers *rxfer;
2475 	struct spi_transfer *xfer;
2476 	size_t i;
2477 
2478 	/* allocate the structure using spi_res */
2479 	rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2480 			      insert * sizeof(struct spi_transfer)
2481 			      + sizeof(struct spi_replaced_transfers)
2482 			      + extradatasize,
2483 			      gfp);
2484 	if (!rxfer)
2485 		return ERR_PTR(-ENOMEM);
2486 
2487 	/* the release code to invoke before running the generic release */
2488 	rxfer->release = release;
2489 
2490 	/* assign extradata */
2491 	if (extradatasize)
2492 		rxfer->extradata =
2493 			&rxfer->inserted_transfers[insert];
2494 
2495 	/* init the replaced_transfers list */
2496 	INIT_LIST_HEAD(&rxfer->replaced_transfers);
2497 
2498 	/* assign the list_entry after which we should reinsert
2499 	 * the @replaced_transfers - it may be spi_message.messages!
2500 	 */
2501 	rxfer->replaced_after = xfer_first->transfer_list.prev;
2502 
2503 	/* remove the requested number of transfers */
2504 	for (i = 0; i < remove; i++) {
2505 		/* if the entry after replaced_after it is msg->transfers
2506 		 * then we have been requested to remove more transfers
2507 		 * than are in the list
2508 		 */
2509 		if (rxfer->replaced_after->next == &msg->transfers) {
2510 			dev_err(&msg->spi->dev,
2511 				"requested to remove more spi_transfers than are available\n");
2512 			/* insert replaced transfers back into the message */
2513 			list_splice(&rxfer->replaced_transfers,
2514 				    rxfer->replaced_after);
2515 
2516 			/* free the spi_replace_transfer structure */
2517 			spi_res_free(rxfer);
2518 
2519 			/* and return with an error */
2520 			return ERR_PTR(-EINVAL);
2521 		}
2522 
2523 		/* remove the entry after replaced_after from list of
2524 		 * transfers and add it to list of replaced_transfers
2525 		 */
2526 		list_move_tail(rxfer->replaced_after->next,
2527 			       &rxfer->replaced_transfers);
2528 	}
2529 
2530 	/* create copy of the given xfer with identical settings
2531 	 * based on the first transfer to get removed
2532 	 */
2533 	for (i = 0; i < insert; i++) {
2534 		/* we need to run in reverse order */
2535 		xfer = &rxfer->inserted_transfers[insert - 1 - i];
2536 
2537 		/* copy all spi_transfer data */
2538 		memcpy(xfer, xfer_first, sizeof(*xfer));
2539 
2540 		/* add to list */
2541 		list_add(&xfer->transfer_list, rxfer->replaced_after);
2542 
2543 		/* clear cs_change and delay_usecs for all but the last */
2544 		if (i) {
2545 			xfer->cs_change = false;
2546 			xfer->delay_usecs = 0;
2547 		}
2548 	}
2549 
2550 	/* set up inserted */
2551 	rxfer->inserted = insert;
2552 
2553 	/* and register it with spi_res/spi_message */
2554 	spi_res_add(msg, rxfer);
2555 
2556 	return rxfer;
2557 }
2558 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2559 
2560 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2561 					struct spi_message *msg,
2562 					struct spi_transfer **xferp,
2563 					size_t maxsize,
2564 					gfp_t gfp)
2565 {
2566 	struct spi_transfer *xfer = *xferp, *xfers;
2567 	struct spi_replaced_transfers *srt;
2568 	size_t offset;
2569 	size_t count, i;
2570 
2571 	/* warn once about this fact that we are splitting a transfer */
2572 	dev_warn_once(&msg->spi->dev,
2573 		      "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2574 		      xfer->len, maxsize);
2575 
2576 	/* calculate how many we have to replace */
2577 	count = DIV_ROUND_UP(xfer->len, maxsize);
2578 
2579 	/* create replacement */
2580 	srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2581 	if (IS_ERR(srt))
2582 		return PTR_ERR(srt);
2583 	xfers = srt->inserted_transfers;
2584 
2585 	/* now handle each of those newly inserted spi_transfers
2586 	 * note that the replacements spi_transfers all are preset
2587 	 * to the same values as *xferp, so tx_buf, rx_buf and len
2588 	 * are all identical (as well as most others)
2589 	 * so we just have to fix up len and the pointers.
2590 	 *
2591 	 * this also includes support for the depreciated
2592 	 * spi_message.is_dma_mapped interface
2593 	 */
2594 
2595 	/* the first transfer just needs the length modified, so we
2596 	 * run it outside the loop
2597 	 */
2598 	xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2599 
2600 	/* all the others need rx_buf/tx_buf also set */
2601 	for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2602 		/* update rx_buf, tx_buf and dma */
2603 		if (xfers[i].rx_buf)
2604 			xfers[i].rx_buf += offset;
2605 		if (xfers[i].rx_dma)
2606 			xfers[i].rx_dma += offset;
2607 		if (xfers[i].tx_buf)
2608 			xfers[i].tx_buf += offset;
2609 		if (xfers[i].tx_dma)
2610 			xfers[i].tx_dma += offset;
2611 
2612 		/* update length */
2613 		xfers[i].len = min(maxsize, xfers[i].len - offset);
2614 	}
2615 
2616 	/* we set up xferp to the last entry we have inserted,
2617 	 * so that we skip those already split transfers
2618 	 */
2619 	*xferp = &xfers[count - 1];
2620 
2621 	/* increment statistics counters */
2622 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2623 				       transfers_split_maxsize);
2624 	SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2625 				       transfers_split_maxsize);
2626 
2627 	return 0;
2628 }
2629 
2630 /**
2631  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2632  *                              when an individual transfer exceeds a
2633  *                              certain size
2634  * @ctlr:    the @spi_controller for this transfer
2635  * @msg:   the @spi_message to transform
2636  * @maxsize:  the maximum when to apply this
2637  * @gfp: GFP allocation flags
2638  *
2639  * Return: status of transformation
2640  */
2641 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2642 				struct spi_message *msg,
2643 				size_t maxsize,
2644 				gfp_t gfp)
2645 {
2646 	struct spi_transfer *xfer;
2647 	int ret;
2648 
2649 	/* iterate over the transfer_list,
2650 	 * but note that xfer is advanced to the last transfer inserted
2651 	 * to avoid checking sizes again unnecessarily (also xfer does
2652 	 * potentiall belong to a different list by the time the
2653 	 * replacement has happened
2654 	 */
2655 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2656 		if (xfer->len > maxsize) {
2657 			ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2658 							   maxsize, gfp);
2659 			if (ret)
2660 				return ret;
2661 		}
2662 	}
2663 
2664 	return 0;
2665 }
2666 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2667 
2668 /*-------------------------------------------------------------------------*/
2669 
2670 /* Core methods for SPI controller protocol drivers.  Some of the
2671  * other core methods are currently defined as inline functions.
2672  */
2673 
2674 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2675 					u8 bits_per_word)
2676 {
2677 	if (ctlr->bits_per_word_mask) {
2678 		/* Only 32 bits fit in the mask */
2679 		if (bits_per_word > 32)
2680 			return -EINVAL;
2681 		if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2682 			return -EINVAL;
2683 	}
2684 
2685 	return 0;
2686 }
2687 
2688 /**
2689  * spi_setup - setup SPI mode and clock rate
2690  * @spi: the device whose settings are being modified
2691  * Context: can sleep, and no requests are queued to the device
2692  *
2693  * SPI protocol drivers may need to update the transfer mode if the
2694  * device doesn't work with its default.  They may likewise need
2695  * to update clock rates or word sizes from initial values.  This function
2696  * changes those settings, and must be called from a context that can sleep.
2697  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2698  * effect the next time the device is selected and data is transferred to
2699  * or from it.  When this function returns, the spi device is deselected.
2700  *
2701  * Note that this call will fail if the protocol driver specifies an option
2702  * that the underlying controller or its driver does not support.  For
2703  * example, not all hardware supports wire transfers using nine bit words,
2704  * LSB-first wire encoding, or active-high chipselects.
2705  *
2706  * Return: zero on success, else a negative error code.
2707  */
2708 int spi_setup(struct spi_device *spi)
2709 {
2710 	unsigned	bad_bits, ugly_bits;
2711 	int		status;
2712 
2713 	/* check mode to prevent that DUAL and QUAD set at the same time
2714 	 */
2715 	if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2716 		((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2717 		dev_err(&spi->dev,
2718 		"setup: can not select dual and quad at the same time\n");
2719 		return -EINVAL;
2720 	}
2721 	/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2722 	 */
2723 	if ((spi->mode & SPI_3WIRE) && (spi->mode &
2724 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2725 		return -EINVAL;
2726 	/* help drivers fail *cleanly* when they need options
2727 	 * that aren't supported with their current controller
2728 	 */
2729 	bad_bits = spi->mode & ~spi->controller->mode_bits;
2730 	ugly_bits = bad_bits &
2731 		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2732 	if (ugly_bits) {
2733 		dev_warn(&spi->dev,
2734 			 "setup: ignoring unsupported mode bits %x\n",
2735 			 ugly_bits);
2736 		spi->mode &= ~ugly_bits;
2737 		bad_bits &= ~ugly_bits;
2738 	}
2739 	if (bad_bits) {
2740 		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2741 			bad_bits);
2742 		return -EINVAL;
2743 	}
2744 
2745 	if (!spi->bits_per_word)
2746 		spi->bits_per_word = 8;
2747 
2748 	status = __spi_validate_bits_per_word(spi->controller,
2749 					      spi->bits_per_word);
2750 	if (status)
2751 		return status;
2752 
2753 	if (!spi->max_speed_hz)
2754 		spi->max_speed_hz = spi->controller->max_speed_hz;
2755 
2756 	if (spi->controller->setup)
2757 		status = spi->controller->setup(spi);
2758 
2759 	spi_set_cs(spi, false);
2760 
2761 	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2762 			(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2763 			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2764 			(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2765 			(spi->mode & SPI_3WIRE) ? "3wire, " : "",
2766 			(spi->mode & SPI_LOOP) ? "loopback, " : "",
2767 			spi->bits_per_word, spi->max_speed_hz,
2768 			status);
2769 
2770 	return status;
2771 }
2772 EXPORT_SYMBOL_GPL(spi_setup);
2773 
2774 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2775 {
2776 	struct spi_controller *ctlr = spi->controller;
2777 	struct spi_transfer *xfer;
2778 	int w_size;
2779 
2780 	if (list_empty(&message->transfers))
2781 		return -EINVAL;
2782 
2783 	/* Half-duplex links include original MicroWire, and ones with
2784 	 * only one data pin like SPI_3WIRE (switches direction) or where
2785 	 * either MOSI or MISO is missing.  They can also be caused by
2786 	 * software limitations.
2787 	 */
2788 	if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2789 	    (spi->mode & SPI_3WIRE)) {
2790 		unsigned flags = ctlr->flags;
2791 
2792 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
2793 			if (xfer->rx_buf && xfer->tx_buf)
2794 				return -EINVAL;
2795 			if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2796 				return -EINVAL;
2797 			if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2798 				return -EINVAL;
2799 		}
2800 	}
2801 
2802 	/**
2803 	 * Set transfer bits_per_word and max speed as spi device default if
2804 	 * it is not set for this transfer.
2805 	 * Set transfer tx_nbits and rx_nbits as single transfer default
2806 	 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2807 	 */
2808 	message->frame_length = 0;
2809 	list_for_each_entry(xfer, &message->transfers, transfer_list) {
2810 		message->frame_length += xfer->len;
2811 		if (!xfer->bits_per_word)
2812 			xfer->bits_per_word = spi->bits_per_word;
2813 
2814 		if (!xfer->speed_hz)
2815 			xfer->speed_hz = spi->max_speed_hz;
2816 		if (!xfer->speed_hz)
2817 			xfer->speed_hz = ctlr->max_speed_hz;
2818 
2819 		if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2820 			xfer->speed_hz = ctlr->max_speed_hz;
2821 
2822 		if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2823 			return -EINVAL;
2824 
2825 		/*
2826 		 * SPI transfer length should be multiple of SPI word size
2827 		 * where SPI word size should be power-of-two multiple
2828 		 */
2829 		if (xfer->bits_per_word <= 8)
2830 			w_size = 1;
2831 		else if (xfer->bits_per_word <= 16)
2832 			w_size = 2;
2833 		else
2834 			w_size = 4;
2835 
2836 		/* No partial transfers accepted */
2837 		if (xfer->len % w_size)
2838 			return -EINVAL;
2839 
2840 		if (xfer->speed_hz && ctlr->min_speed_hz &&
2841 		    xfer->speed_hz < ctlr->min_speed_hz)
2842 			return -EINVAL;
2843 
2844 		if (xfer->tx_buf && !xfer->tx_nbits)
2845 			xfer->tx_nbits = SPI_NBITS_SINGLE;
2846 		if (xfer->rx_buf && !xfer->rx_nbits)
2847 			xfer->rx_nbits = SPI_NBITS_SINGLE;
2848 		/* check transfer tx/rx_nbits:
2849 		 * 1. check the value matches one of single, dual and quad
2850 		 * 2. check tx/rx_nbits match the mode in spi_device
2851 		 */
2852 		if (xfer->tx_buf) {
2853 			if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2854 				xfer->tx_nbits != SPI_NBITS_DUAL &&
2855 				xfer->tx_nbits != SPI_NBITS_QUAD)
2856 				return -EINVAL;
2857 			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2858 				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2859 				return -EINVAL;
2860 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2861 				!(spi->mode & SPI_TX_QUAD))
2862 				return -EINVAL;
2863 		}
2864 		/* check transfer rx_nbits */
2865 		if (xfer->rx_buf) {
2866 			if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2867 				xfer->rx_nbits != SPI_NBITS_DUAL &&
2868 				xfer->rx_nbits != SPI_NBITS_QUAD)
2869 				return -EINVAL;
2870 			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2871 				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2872 				return -EINVAL;
2873 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2874 				!(spi->mode & SPI_RX_QUAD))
2875 				return -EINVAL;
2876 		}
2877 	}
2878 
2879 	message->status = -EINPROGRESS;
2880 
2881 	return 0;
2882 }
2883 
2884 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2885 {
2886 	struct spi_controller *ctlr = spi->controller;
2887 
2888 	message->spi = spi;
2889 
2890 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
2891 	SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2892 
2893 	trace_spi_message_submit(message);
2894 
2895 	return ctlr->transfer(spi, message);
2896 }
2897 
2898 /**
2899  * spi_async - asynchronous SPI transfer
2900  * @spi: device with which data will be exchanged
2901  * @message: describes the data transfers, including completion callback
2902  * Context: any (irqs may be blocked, etc)
2903  *
2904  * This call may be used in_irq and other contexts which can't sleep,
2905  * as well as from task contexts which can sleep.
2906  *
2907  * The completion callback is invoked in a context which can't sleep.
2908  * Before that invocation, the value of message->status is undefined.
2909  * When the callback is issued, message->status holds either zero (to
2910  * indicate complete success) or a negative error code.  After that
2911  * callback returns, the driver which issued the transfer request may
2912  * deallocate the associated memory; it's no longer in use by any SPI
2913  * core or controller driver code.
2914  *
2915  * Note that although all messages to a spi_device are handled in
2916  * FIFO order, messages may go to different devices in other orders.
2917  * Some device might be higher priority, or have various "hard" access
2918  * time requirements, for example.
2919  *
2920  * On detection of any fault during the transfer, processing of
2921  * the entire message is aborted, and the device is deselected.
2922  * Until returning from the associated message completion callback,
2923  * no other spi_message queued to that device will be processed.
2924  * (This rule applies equally to all the synchronous transfer calls,
2925  * which are wrappers around this core asynchronous primitive.)
2926  *
2927  * Return: zero on success, else a negative error code.
2928  */
2929 int spi_async(struct spi_device *spi, struct spi_message *message)
2930 {
2931 	struct spi_controller *ctlr = spi->controller;
2932 	int ret;
2933 	unsigned long flags;
2934 
2935 	ret = __spi_validate(spi, message);
2936 	if (ret != 0)
2937 		return ret;
2938 
2939 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2940 
2941 	if (ctlr->bus_lock_flag)
2942 		ret = -EBUSY;
2943 	else
2944 		ret = __spi_async(spi, message);
2945 
2946 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2947 
2948 	return ret;
2949 }
2950 EXPORT_SYMBOL_GPL(spi_async);
2951 
2952 /**
2953  * spi_async_locked - version of spi_async with exclusive bus usage
2954  * @spi: device with which data will be exchanged
2955  * @message: describes the data transfers, including completion callback
2956  * Context: any (irqs may be blocked, etc)
2957  *
2958  * This call may be used in_irq and other contexts which can't sleep,
2959  * as well as from task contexts which can sleep.
2960  *
2961  * The completion callback is invoked in a context which can't sleep.
2962  * Before that invocation, the value of message->status is undefined.
2963  * When the callback is issued, message->status holds either zero (to
2964  * indicate complete success) or a negative error code.  After that
2965  * callback returns, the driver which issued the transfer request may
2966  * deallocate the associated memory; it's no longer in use by any SPI
2967  * core or controller driver code.
2968  *
2969  * Note that although all messages to a spi_device are handled in
2970  * FIFO order, messages may go to different devices in other orders.
2971  * Some device might be higher priority, or have various "hard" access
2972  * time requirements, for example.
2973  *
2974  * On detection of any fault during the transfer, processing of
2975  * the entire message is aborted, and the device is deselected.
2976  * Until returning from the associated message completion callback,
2977  * no other spi_message queued to that device will be processed.
2978  * (This rule applies equally to all the synchronous transfer calls,
2979  * which are wrappers around this core asynchronous primitive.)
2980  *
2981  * Return: zero on success, else a negative error code.
2982  */
2983 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2984 {
2985 	struct spi_controller *ctlr = spi->controller;
2986 	int ret;
2987 	unsigned long flags;
2988 
2989 	ret = __spi_validate(spi, message);
2990 	if (ret != 0)
2991 		return ret;
2992 
2993 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2994 
2995 	ret = __spi_async(spi, message);
2996 
2997 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2998 
2999 	return ret;
3000 
3001 }
3002 EXPORT_SYMBOL_GPL(spi_async_locked);
3003 
3004 
3005 int spi_flash_read(struct spi_device *spi,
3006 		   struct spi_flash_read_message *msg)
3007 
3008 {
3009 	struct spi_controller *master = spi->controller;
3010 	struct device *rx_dev = NULL;
3011 	int ret;
3012 
3013 	if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
3014 	     msg->addr_nbits == SPI_NBITS_DUAL) &&
3015 	    !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3016 		return -EINVAL;
3017 	if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
3018 	     msg->addr_nbits == SPI_NBITS_QUAD) &&
3019 	    !(spi->mode & SPI_TX_QUAD))
3020 		return -EINVAL;
3021 	if (msg->data_nbits == SPI_NBITS_DUAL &&
3022 	    !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3023 		return -EINVAL;
3024 	if (msg->data_nbits == SPI_NBITS_QUAD &&
3025 	    !(spi->mode &  SPI_RX_QUAD))
3026 		return -EINVAL;
3027 
3028 	if (master->auto_runtime_pm) {
3029 		ret = pm_runtime_get_sync(master->dev.parent);
3030 		if (ret < 0) {
3031 			dev_err(&master->dev, "Failed to power device: %d\n",
3032 				ret);
3033 			return ret;
3034 		}
3035 	}
3036 
3037 	mutex_lock(&master->bus_lock_mutex);
3038 	mutex_lock(&master->io_mutex);
3039 	if (master->dma_rx && master->spi_flash_can_dma(spi, msg)) {
3040 		rx_dev = master->dma_rx->device->dev;
3041 		ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
3042 				  msg->buf, msg->len,
3043 				  DMA_FROM_DEVICE);
3044 		if (!ret)
3045 			msg->cur_msg_mapped = true;
3046 	}
3047 	ret = master->spi_flash_read(spi, msg);
3048 	if (msg->cur_msg_mapped)
3049 		spi_unmap_buf(master, rx_dev, &msg->rx_sg,
3050 			      DMA_FROM_DEVICE);
3051 	mutex_unlock(&master->io_mutex);
3052 	mutex_unlock(&master->bus_lock_mutex);
3053 
3054 	if (master->auto_runtime_pm)
3055 		pm_runtime_put(master->dev.parent);
3056 
3057 	return ret;
3058 }
3059 EXPORT_SYMBOL_GPL(spi_flash_read);
3060 
3061 /*-------------------------------------------------------------------------*/
3062 
3063 /* Utility methods for SPI protocol drivers, layered on
3064  * top of the core.  Some other utility methods are defined as
3065  * inline functions.
3066  */
3067 
3068 static void spi_complete(void *arg)
3069 {
3070 	complete(arg);
3071 }
3072 
3073 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3074 {
3075 	DECLARE_COMPLETION_ONSTACK(done);
3076 	int status;
3077 	struct spi_controller *ctlr = spi->controller;
3078 	unsigned long flags;
3079 
3080 	status = __spi_validate(spi, message);
3081 	if (status != 0)
3082 		return status;
3083 
3084 	message->complete = spi_complete;
3085 	message->context = &done;
3086 	message->spi = spi;
3087 
3088 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3089 	SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3090 
3091 	/* If we're not using the legacy transfer method then we will
3092 	 * try to transfer in the calling context so special case.
3093 	 * This code would be less tricky if we could remove the
3094 	 * support for driver implemented message queues.
3095 	 */
3096 	if (ctlr->transfer == spi_queued_transfer) {
3097 		spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3098 
3099 		trace_spi_message_submit(message);
3100 
3101 		status = __spi_queued_transfer(spi, message, false);
3102 
3103 		spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3104 	} else {
3105 		status = spi_async_locked(spi, message);
3106 	}
3107 
3108 	if (status == 0) {
3109 		/* Push out the messages in the calling context if we
3110 		 * can.
3111 		 */
3112 		if (ctlr->transfer == spi_queued_transfer) {
3113 			SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3114 						       spi_sync_immediate);
3115 			SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3116 						       spi_sync_immediate);
3117 			__spi_pump_messages(ctlr, false);
3118 		}
3119 
3120 		wait_for_completion(&done);
3121 		status = message->status;
3122 	}
3123 	message->context = NULL;
3124 	return status;
3125 }
3126 
3127 /**
3128  * spi_sync - blocking/synchronous SPI data transfers
3129  * @spi: device with which data will be exchanged
3130  * @message: describes the data transfers
3131  * Context: can sleep
3132  *
3133  * This call may only be used from a context that may sleep.  The sleep
3134  * is non-interruptible, and has no timeout.  Low-overhead controller
3135  * drivers may DMA directly into and out of the message buffers.
3136  *
3137  * Note that the SPI device's chip select is active during the message,
3138  * and then is normally disabled between messages.  Drivers for some
3139  * frequently-used devices may want to minimize costs of selecting a chip,
3140  * by leaving it selected in anticipation that the next message will go
3141  * to the same chip.  (That may increase power usage.)
3142  *
3143  * Also, the caller is guaranteeing that the memory associated with the
3144  * message will not be freed before this call returns.
3145  *
3146  * Return: zero on success, else a negative error code.
3147  */
3148 int spi_sync(struct spi_device *spi, struct spi_message *message)
3149 {
3150 	int ret;
3151 
3152 	mutex_lock(&spi->controller->bus_lock_mutex);
3153 	ret = __spi_sync(spi, message);
3154 	mutex_unlock(&spi->controller->bus_lock_mutex);
3155 
3156 	return ret;
3157 }
3158 EXPORT_SYMBOL_GPL(spi_sync);
3159 
3160 /**
3161  * spi_sync_locked - version of spi_sync with exclusive bus usage
3162  * @spi: device with which data will be exchanged
3163  * @message: describes the data transfers
3164  * Context: can sleep
3165  *
3166  * This call may only be used from a context that may sleep.  The sleep
3167  * is non-interruptible, and has no timeout.  Low-overhead controller
3168  * drivers may DMA directly into and out of the message buffers.
3169  *
3170  * This call should be used by drivers that require exclusive access to the
3171  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3172  * be released by a spi_bus_unlock call when the exclusive access is over.
3173  *
3174  * Return: zero on success, else a negative error code.
3175  */
3176 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3177 {
3178 	return __spi_sync(spi, message);
3179 }
3180 EXPORT_SYMBOL_GPL(spi_sync_locked);
3181 
3182 /**
3183  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3184  * @ctlr: SPI bus master that should be locked for exclusive bus access
3185  * Context: can sleep
3186  *
3187  * This call may only be used from a context that may sleep.  The sleep
3188  * is non-interruptible, and has no timeout.
3189  *
3190  * This call should be used by drivers that require exclusive access to the
3191  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3192  * exclusive access is over. Data transfer must be done by spi_sync_locked
3193  * and spi_async_locked calls when the SPI bus lock is held.
3194  *
3195  * Return: always zero.
3196  */
3197 int spi_bus_lock(struct spi_controller *ctlr)
3198 {
3199 	unsigned long flags;
3200 
3201 	mutex_lock(&ctlr->bus_lock_mutex);
3202 
3203 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3204 	ctlr->bus_lock_flag = 1;
3205 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3206 
3207 	/* mutex remains locked until spi_bus_unlock is called */
3208 
3209 	return 0;
3210 }
3211 EXPORT_SYMBOL_GPL(spi_bus_lock);
3212 
3213 /**
3214  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3215  * @ctlr: SPI bus master that was locked for exclusive bus access
3216  * Context: can sleep
3217  *
3218  * This call may only be used from a context that may sleep.  The sleep
3219  * is non-interruptible, and has no timeout.
3220  *
3221  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3222  * call.
3223  *
3224  * Return: always zero.
3225  */
3226 int spi_bus_unlock(struct spi_controller *ctlr)
3227 {
3228 	ctlr->bus_lock_flag = 0;
3229 
3230 	mutex_unlock(&ctlr->bus_lock_mutex);
3231 
3232 	return 0;
3233 }
3234 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3235 
3236 /* portable code must never pass more than 32 bytes */
3237 #define	SPI_BUFSIZ	max(32, SMP_CACHE_BYTES)
3238 
3239 static u8	*buf;
3240 
3241 /**
3242  * spi_write_then_read - SPI synchronous write followed by read
3243  * @spi: device with which data will be exchanged
3244  * @txbuf: data to be written (need not be dma-safe)
3245  * @n_tx: size of txbuf, in bytes
3246  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3247  * @n_rx: size of rxbuf, in bytes
3248  * Context: can sleep
3249  *
3250  * This performs a half duplex MicroWire style transaction with the
3251  * device, sending txbuf and then reading rxbuf.  The return value
3252  * is zero for success, else a negative errno status code.
3253  * This call may only be used from a context that may sleep.
3254  *
3255  * Parameters to this routine are always copied using a small buffer;
3256  * portable code should never use this for more than 32 bytes.
3257  * Performance-sensitive or bulk transfer code should instead use
3258  * spi_{async,sync}() calls with dma-safe buffers.
3259  *
3260  * Return: zero on success, else a negative error code.
3261  */
3262 int spi_write_then_read(struct spi_device *spi,
3263 		const void *txbuf, unsigned n_tx,
3264 		void *rxbuf, unsigned n_rx)
3265 {
3266 	static DEFINE_MUTEX(lock);
3267 
3268 	int			status;
3269 	struct spi_message	message;
3270 	struct spi_transfer	x[2];
3271 	u8			*local_buf;
3272 
3273 	/* Use preallocated DMA-safe buffer if we can.  We can't avoid
3274 	 * copying here, (as a pure convenience thing), but we can
3275 	 * keep heap costs out of the hot path unless someone else is
3276 	 * using the pre-allocated buffer or the transfer is too large.
3277 	 */
3278 	if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3279 		local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3280 				    GFP_KERNEL | GFP_DMA);
3281 		if (!local_buf)
3282 			return -ENOMEM;
3283 	} else {
3284 		local_buf = buf;
3285 	}
3286 
3287 	spi_message_init(&message);
3288 	memset(x, 0, sizeof(x));
3289 	if (n_tx) {
3290 		x[0].len = n_tx;
3291 		spi_message_add_tail(&x[0], &message);
3292 	}
3293 	if (n_rx) {
3294 		x[1].len = n_rx;
3295 		spi_message_add_tail(&x[1], &message);
3296 	}
3297 
3298 	memcpy(local_buf, txbuf, n_tx);
3299 	x[0].tx_buf = local_buf;
3300 	x[1].rx_buf = local_buf + n_tx;
3301 
3302 	/* do the i/o */
3303 	status = spi_sync(spi, &message);
3304 	if (status == 0)
3305 		memcpy(rxbuf, x[1].rx_buf, n_rx);
3306 
3307 	if (x[0].tx_buf == buf)
3308 		mutex_unlock(&lock);
3309 	else
3310 		kfree(local_buf);
3311 
3312 	return status;
3313 }
3314 EXPORT_SYMBOL_GPL(spi_write_then_read);
3315 
3316 /*-------------------------------------------------------------------------*/
3317 
3318 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3319 static int __spi_of_device_match(struct device *dev, void *data)
3320 {
3321 	return dev->of_node == data;
3322 }
3323 
3324 /* must call put_device() when done with returned spi_device device */
3325 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3326 {
3327 	struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3328 						__spi_of_device_match);
3329 	return dev ? to_spi_device(dev) : NULL;
3330 }
3331 
3332 static int __spi_of_controller_match(struct device *dev, const void *data)
3333 {
3334 	return dev->of_node == data;
3335 }
3336 
3337 /* the spi controllers are not using spi_bus, so we find it with another way */
3338 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3339 {
3340 	struct device *dev;
3341 
3342 	dev = class_find_device(&spi_master_class, NULL, node,
3343 				__spi_of_controller_match);
3344 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3345 		dev = class_find_device(&spi_slave_class, NULL, node,
3346 					__spi_of_controller_match);
3347 	if (!dev)
3348 		return NULL;
3349 
3350 	/* reference got in class_find_device */
3351 	return container_of(dev, struct spi_controller, dev);
3352 }
3353 
3354 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3355 			 void *arg)
3356 {
3357 	struct of_reconfig_data *rd = arg;
3358 	struct spi_controller *ctlr;
3359 	struct spi_device *spi;
3360 
3361 	switch (of_reconfig_get_state_change(action, arg)) {
3362 	case OF_RECONFIG_CHANGE_ADD:
3363 		ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3364 		if (ctlr == NULL)
3365 			return NOTIFY_OK;	/* not for us */
3366 
3367 		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3368 			put_device(&ctlr->dev);
3369 			return NOTIFY_OK;
3370 		}
3371 
3372 		spi = of_register_spi_device(ctlr, rd->dn);
3373 		put_device(&ctlr->dev);
3374 
3375 		if (IS_ERR(spi)) {
3376 			pr_err("%s: failed to create for '%pOF'\n",
3377 					__func__, rd->dn);
3378 			of_node_clear_flag(rd->dn, OF_POPULATED);
3379 			return notifier_from_errno(PTR_ERR(spi));
3380 		}
3381 		break;
3382 
3383 	case OF_RECONFIG_CHANGE_REMOVE:
3384 		/* already depopulated? */
3385 		if (!of_node_check_flag(rd->dn, OF_POPULATED))
3386 			return NOTIFY_OK;
3387 
3388 		/* find our device by node */
3389 		spi = of_find_spi_device_by_node(rd->dn);
3390 		if (spi == NULL)
3391 			return NOTIFY_OK;	/* no? not meant for us */
3392 
3393 		/* unregister takes one ref away */
3394 		spi_unregister_device(spi);
3395 
3396 		/* and put the reference of the find */
3397 		put_device(&spi->dev);
3398 		break;
3399 	}
3400 
3401 	return NOTIFY_OK;
3402 }
3403 
3404 static struct notifier_block spi_of_notifier = {
3405 	.notifier_call = of_spi_notify,
3406 };
3407 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3408 extern struct notifier_block spi_of_notifier;
3409 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3410 
3411 #if IS_ENABLED(CONFIG_ACPI)
3412 static int spi_acpi_controller_match(struct device *dev, const void *data)
3413 {
3414 	return ACPI_COMPANION(dev->parent) == data;
3415 }
3416 
3417 static int spi_acpi_device_match(struct device *dev, void *data)
3418 {
3419 	return ACPI_COMPANION(dev) == data;
3420 }
3421 
3422 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3423 {
3424 	struct device *dev;
3425 
3426 	dev = class_find_device(&spi_master_class, NULL, adev,
3427 				spi_acpi_controller_match);
3428 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3429 		dev = class_find_device(&spi_slave_class, NULL, adev,
3430 					spi_acpi_controller_match);
3431 	if (!dev)
3432 		return NULL;
3433 
3434 	return container_of(dev, struct spi_controller, dev);
3435 }
3436 
3437 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3438 {
3439 	struct device *dev;
3440 
3441 	dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3442 
3443 	return dev ? to_spi_device(dev) : NULL;
3444 }
3445 
3446 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3447 			   void *arg)
3448 {
3449 	struct acpi_device *adev = arg;
3450 	struct spi_controller *ctlr;
3451 	struct spi_device *spi;
3452 
3453 	switch (value) {
3454 	case ACPI_RECONFIG_DEVICE_ADD:
3455 		ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3456 		if (!ctlr)
3457 			break;
3458 
3459 		acpi_register_spi_device(ctlr, adev);
3460 		put_device(&ctlr->dev);
3461 		break;
3462 	case ACPI_RECONFIG_DEVICE_REMOVE:
3463 		if (!acpi_device_enumerated(adev))
3464 			break;
3465 
3466 		spi = acpi_spi_find_device_by_adev(adev);
3467 		if (!spi)
3468 			break;
3469 
3470 		spi_unregister_device(spi);
3471 		put_device(&spi->dev);
3472 		break;
3473 	}
3474 
3475 	return NOTIFY_OK;
3476 }
3477 
3478 static struct notifier_block spi_acpi_notifier = {
3479 	.notifier_call = acpi_spi_notify,
3480 };
3481 #else
3482 extern struct notifier_block spi_acpi_notifier;
3483 #endif
3484 
3485 static int __init spi_init(void)
3486 {
3487 	int	status;
3488 
3489 	buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3490 	if (!buf) {
3491 		status = -ENOMEM;
3492 		goto err0;
3493 	}
3494 
3495 	status = bus_register(&spi_bus_type);
3496 	if (status < 0)
3497 		goto err1;
3498 
3499 	status = class_register(&spi_master_class);
3500 	if (status < 0)
3501 		goto err2;
3502 
3503 	if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3504 		status = class_register(&spi_slave_class);
3505 		if (status < 0)
3506 			goto err3;
3507 	}
3508 
3509 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3510 		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3511 	if (IS_ENABLED(CONFIG_ACPI))
3512 		WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3513 
3514 	return 0;
3515 
3516 err3:
3517 	class_unregister(&spi_master_class);
3518 err2:
3519 	bus_unregister(&spi_bus_type);
3520 err1:
3521 	kfree(buf);
3522 	buf = NULL;
3523 err0:
3524 	return status;
3525 }
3526 
3527 /* board_info is normally registered in arch_initcall(),
3528  * but even essential drivers wait till later
3529  *
3530  * REVISIT only boardinfo really needs static linking. the rest (device and
3531  * driver registration) _could_ be dynamically linked (modular) ... costs
3532  * include needing to have boardinfo data structures be much more public.
3533  */
3534 postcore_initcall(spi_init);
3535 
3536