xref: /openbmc/linux/drivers/spi/spi.c (revision 9659281c)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 // SPI init/core code
3 //
4 // Copyright (C) 2005 David Brownell
5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
6 
7 #include <linux/kernel.h>
8 #include <linux/device.h>
9 #include <linux/init.h>
10 #include <linux/cache.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/dmaengine.h>
13 #include <linux/mutex.h>
14 #include <linux/of_device.h>
15 #include <linux/of_irq.h>
16 #include <linux/clk/clk-conf.h>
17 #include <linux/slab.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi-mem.h>
21 #include <linux/of_gpio.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/pm_domain.h>
25 #include <linux/property.h>
26 #include <linux/export.h>
27 #include <linux/sched/rt.h>
28 #include <uapi/linux/sched/types.h>
29 #include <linux/delay.h>
30 #include <linux/kthread.h>
31 #include <linux/ioport.h>
32 #include <linux/acpi.h>
33 #include <linux/highmem.h>
34 #include <linux/idr.h>
35 #include <linux/platform_data/x86/apple.h>
36 
37 #define CREATE_TRACE_POINTS
38 #include <trace/events/spi.h>
39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
41 
42 #include "internals.h"
43 
44 static DEFINE_IDR(spi_master_idr);
45 
46 static void spidev_release(struct device *dev)
47 {
48 	struct spi_device	*spi = to_spi_device(dev);
49 
50 	spi_controller_put(spi->controller);
51 	kfree(spi->driver_override);
52 	kfree(spi);
53 }
54 
55 static ssize_t
56 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
57 {
58 	const struct spi_device	*spi = to_spi_device(dev);
59 	int len;
60 
61 	len = of_device_modalias(dev, buf, PAGE_SIZE);
62 	if (len != -ENODEV)
63 		return len;
64 
65 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 	if (len != -ENODEV)
67 		return len;
68 
69 	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
70 }
71 static DEVICE_ATTR_RO(modalias);
72 
73 static ssize_t driver_override_store(struct device *dev,
74 				     struct device_attribute *a,
75 				     const char *buf, size_t count)
76 {
77 	struct spi_device *spi = to_spi_device(dev);
78 	const char *end = memchr(buf, '\n', count);
79 	const size_t len = end ? end - buf : count;
80 	const char *driver_override, *old;
81 
82 	/* We need to keep extra room for a newline when displaying value */
83 	if (len >= (PAGE_SIZE - 1))
84 		return -EINVAL;
85 
86 	driver_override = kstrndup(buf, len, GFP_KERNEL);
87 	if (!driver_override)
88 		return -ENOMEM;
89 
90 	device_lock(dev);
91 	old = spi->driver_override;
92 	if (len) {
93 		spi->driver_override = driver_override;
94 	} else {
95 		/* Empty string, disable driver override */
96 		spi->driver_override = NULL;
97 		kfree(driver_override);
98 	}
99 	device_unlock(dev);
100 	kfree(old);
101 
102 	return count;
103 }
104 
105 static ssize_t driver_override_show(struct device *dev,
106 				    struct device_attribute *a, char *buf)
107 {
108 	const struct spi_device *spi = to_spi_device(dev);
109 	ssize_t len;
110 
111 	device_lock(dev);
112 	len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
113 	device_unlock(dev);
114 	return len;
115 }
116 static DEVICE_ATTR_RW(driver_override);
117 
118 #define SPI_STATISTICS_ATTRS(field, file)				\
119 static ssize_t spi_controller_##field##_show(struct device *dev,	\
120 					     struct device_attribute *attr, \
121 					     char *buf)			\
122 {									\
123 	struct spi_controller *ctlr = container_of(dev,			\
124 					 struct spi_controller, dev);	\
125 	return spi_statistics_##field##_show(&ctlr->statistics, buf);	\
126 }									\
127 static struct device_attribute dev_attr_spi_controller_##field = {	\
128 	.attr = { .name = file, .mode = 0444 },				\
129 	.show = spi_controller_##field##_show,				\
130 };									\
131 static ssize_t spi_device_##field##_show(struct device *dev,		\
132 					 struct device_attribute *attr,	\
133 					char *buf)			\
134 {									\
135 	struct spi_device *spi = to_spi_device(dev);			\
136 	return spi_statistics_##field##_show(&spi->statistics, buf);	\
137 }									\
138 static struct device_attribute dev_attr_spi_device_##field = {		\
139 	.attr = { .name = file, .mode = 0444 },				\
140 	.show = spi_device_##field##_show,				\
141 }
142 
143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)	\
144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
145 					    char *buf)			\
146 {									\
147 	unsigned long flags;						\
148 	ssize_t len;							\
149 	spin_lock_irqsave(&stat->lock, flags);				\
150 	len = sprintf(buf, format_string, stat->field);			\
151 	spin_unlock_irqrestore(&stat->lock, flags);			\
152 	return len;							\
153 }									\
154 SPI_STATISTICS_ATTRS(name, file)
155 
156 #define SPI_STATISTICS_SHOW(field, format_string)			\
157 	SPI_STATISTICS_SHOW_NAME(field, __stringify(field),		\
158 				 field, format_string)
159 
160 SPI_STATISTICS_SHOW(messages, "%lu");
161 SPI_STATISTICS_SHOW(transfers, "%lu");
162 SPI_STATISTICS_SHOW(errors, "%lu");
163 SPI_STATISTICS_SHOW(timedout, "%lu");
164 
165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
167 SPI_STATISTICS_SHOW(spi_async, "%lu");
168 
169 SPI_STATISTICS_SHOW(bytes, "%llu");
170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
172 
173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)		\
174 	SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,		\
175 				 "transfer_bytes_histo_" number,	\
176 				 transfer_bytes_histo[index],  "%lu")
177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
194 
195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
196 
197 static struct attribute *spi_dev_attrs[] = {
198 	&dev_attr_modalias.attr,
199 	&dev_attr_driver_override.attr,
200 	NULL,
201 };
202 
203 static const struct attribute_group spi_dev_group = {
204 	.attrs  = spi_dev_attrs,
205 };
206 
207 static struct attribute *spi_device_statistics_attrs[] = {
208 	&dev_attr_spi_device_messages.attr,
209 	&dev_attr_spi_device_transfers.attr,
210 	&dev_attr_spi_device_errors.attr,
211 	&dev_attr_spi_device_timedout.attr,
212 	&dev_attr_spi_device_spi_sync.attr,
213 	&dev_attr_spi_device_spi_sync_immediate.attr,
214 	&dev_attr_spi_device_spi_async.attr,
215 	&dev_attr_spi_device_bytes.attr,
216 	&dev_attr_spi_device_bytes_rx.attr,
217 	&dev_attr_spi_device_bytes_tx.attr,
218 	&dev_attr_spi_device_transfer_bytes_histo0.attr,
219 	&dev_attr_spi_device_transfer_bytes_histo1.attr,
220 	&dev_attr_spi_device_transfer_bytes_histo2.attr,
221 	&dev_attr_spi_device_transfer_bytes_histo3.attr,
222 	&dev_attr_spi_device_transfer_bytes_histo4.attr,
223 	&dev_attr_spi_device_transfer_bytes_histo5.attr,
224 	&dev_attr_spi_device_transfer_bytes_histo6.attr,
225 	&dev_attr_spi_device_transfer_bytes_histo7.attr,
226 	&dev_attr_spi_device_transfer_bytes_histo8.attr,
227 	&dev_attr_spi_device_transfer_bytes_histo9.attr,
228 	&dev_attr_spi_device_transfer_bytes_histo10.attr,
229 	&dev_attr_spi_device_transfer_bytes_histo11.attr,
230 	&dev_attr_spi_device_transfer_bytes_histo12.attr,
231 	&dev_attr_spi_device_transfer_bytes_histo13.attr,
232 	&dev_attr_spi_device_transfer_bytes_histo14.attr,
233 	&dev_attr_spi_device_transfer_bytes_histo15.attr,
234 	&dev_attr_spi_device_transfer_bytes_histo16.attr,
235 	&dev_attr_spi_device_transfers_split_maxsize.attr,
236 	NULL,
237 };
238 
239 static const struct attribute_group spi_device_statistics_group = {
240 	.name  = "statistics",
241 	.attrs  = spi_device_statistics_attrs,
242 };
243 
244 static const struct attribute_group *spi_dev_groups[] = {
245 	&spi_dev_group,
246 	&spi_device_statistics_group,
247 	NULL,
248 };
249 
250 static struct attribute *spi_controller_statistics_attrs[] = {
251 	&dev_attr_spi_controller_messages.attr,
252 	&dev_attr_spi_controller_transfers.attr,
253 	&dev_attr_spi_controller_errors.attr,
254 	&dev_attr_spi_controller_timedout.attr,
255 	&dev_attr_spi_controller_spi_sync.attr,
256 	&dev_attr_spi_controller_spi_sync_immediate.attr,
257 	&dev_attr_spi_controller_spi_async.attr,
258 	&dev_attr_spi_controller_bytes.attr,
259 	&dev_attr_spi_controller_bytes_rx.attr,
260 	&dev_attr_spi_controller_bytes_tx.attr,
261 	&dev_attr_spi_controller_transfer_bytes_histo0.attr,
262 	&dev_attr_spi_controller_transfer_bytes_histo1.attr,
263 	&dev_attr_spi_controller_transfer_bytes_histo2.attr,
264 	&dev_attr_spi_controller_transfer_bytes_histo3.attr,
265 	&dev_attr_spi_controller_transfer_bytes_histo4.attr,
266 	&dev_attr_spi_controller_transfer_bytes_histo5.attr,
267 	&dev_attr_spi_controller_transfer_bytes_histo6.attr,
268 	&dev_attr_spi_controller_transfer_bytes_histo7.attr,
269 	&dev_attr_spi_controller_transfer_bytes_histo8.attr,
270 	&dev_attr_spi_controller_transfer_bytes_histo9.attr,
271 	&dev_attr_spi_controller_transfer_bytes_histo10.attr,
272 	&dev_attr_spi_controller_transfer_bytes_histo11.attr,
273 	&dev_attr_spi_controller_transfer_bytes_histo12.attr,
274 	&dev_attr_spi_controller_transfer_bytes_histo13.attr,
275 	&dev_attr_spi_controller_transfer_bytes_histo14.attr,
276 	&dev_attr_spi_controller_transfer_bytes_histo15.attr,
277 	&dev_attr_spi_controller_transfer_bytes_histo16.attr,
278 	&dev_attr_spi_controller_transfers_split_maxsize.attr,
279 	NULL,
280 };
281 
282 static const struct attribute_group spi_controller_statistics_group = {
283 	.name  = "statistics",
284 	.attrs  = spi_controller_statistics_attrs,
285 };
286 
287 static const struct attribute_group *spi_master_groups[] = {
288 	&spi_controller_statistics_group,
289 	NULL,
290 };
291 
292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
293 				       struct spi_transfer *xfer,
294 				       struct spi_controller *ctlr)
295 {
296 	unsigned long flags;
297 	int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
298 
299 	if (l2len < 0)
300 		l2len = 0;
301 
302 	spin_lock_irqsave(&stats->lock, flags);
303 
304 	stats->transfers++;
305 	stats->transfer_bytes_histo[l2len]++;
306 
307 	stats->bytes += xfer->len;
308 	if ((xfer->tx_buf) &&
309 	    (xfer->tx_buf != ctlr->dummy_tx))
310 		stats->bytes_tx += xfer->len;
311 	if ((xfer->rx_buf) &&
312 	    (xfer->rx_buf != ctlr->dummy_rx))
313 		stats->bytes_rx += xfer->len;
314 
315 	spin_unlock_irqrestore(&stats->lock, flags);
316 }
317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
318 
319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
320  * and the sysfs version makes coldplug work too.
321  */
322 
323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
324 						const struct spi_device *sdev)
325 {
326 	while (id->name[0]) {
327 		if (!strcmp(sdev->modalias, id->name))
328 			return id;
329 		id++;
330 	}
331 	return NULL;
332 }
333 
334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
335 {
336 	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
337 
338 	return spi_match_id(sdrv->id_table, sdev);
339 }
340 EXPORT_SYMBOL_GPL(spi_get_device_id);
341 
342 static int spi_match_device(struct device *dev, struct device_driver *drv)
343 {
344 	const struct spi_device	*spi = to_spi_device(dev);
345 	const struct spi_driver	*sdrv = to_spi_driver(drv);
346 
347 	/* Check override first, and if set, only use the named driver */
348 	if (spi->driver_override)
349 		return strcmp(spi->driver_override, drv->name) == 0;
350 
351 	/* Attempt an OF style match */
352 	if (of_driver_match_device(dev, drv))
353 		return 1;
354 
355 	/* Then try ACPI */
356 	if (acpi_driver_match_device(dev, drv))
357 		return 1;
358 
359 	if (sdrv->id_table)
360 		return !!spi_match_id(sdrv->id_table, spi);
361 
362 	return strcmp(spi->modalias, drv->name) == 0;
363 }
364 
365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
366 {
367 	const struct spi_device		*spi = to_spi_device(dev);
368 	int rc;
369 
370 	rc = of_device_uevent_modalias(dev, env);
371 	if (rc != -ENODEV)
372 		return rc;
373 
374 	rc = acpi_device_uevent_modalias(dev, env);
375 	if (rc != -ENODEV)
376 		return rc;
377 
378 	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
379 }
380 
381 static int spi_probe(struct device *dev)
382 {
383 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
384 	struct spi_device		*spi = to_spi_device(dev);
385 	int ret;
386 
387 	ret = of_clk_set_defaults(dev->of_node, false);
388 	if (ret)
389 		return ret;
390 
391 	if (dev->of_node) {
392 		spi->irq = of_irq_get(dev->of_node, 0);
393 		if (spi->irq == -EPROBE_DEFER)
394 			return -EPROBE_DEFER;
395 		if (spi->irq < 0)
396 			spi->irq = 0;
397 	}
398 
399 	ret = dev_pm_domain_attach(dev, true);
400 	if (ret)
401 		return ret;
402 
403 	if (sdrv->probe) {
404 		ret = sdrv->probe(spi);
405 		if (ret)
406 			dev_pm_domain_detach(dev, true);
407 	}
408 
409 	return ret;
410 }
411 
412 static int spi_remove(struct device *dev)
413 {
414 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
415 
416 	if (sdrv->remove) {
417 		int ret;
418 
419 		ret = sdrv->remove(to_spi_device(dev));
420 		if (ret)
421 			dev_warn(dev,
422 				 "Failed to unbind driver (%pe), ignoring\n",
423 				 ERR_PTR(ret));
424 	}
425 
426 	dev_pm_domain_detach(dev, true);
427 
428 	return 0;
429 }
430 
431 static void spi_shutdown(struct device *dev)
432 {
433 	if (dev->driver) {
434 		const struct spi_driver	*sdrv = to_spi_driver(dev->driver);
435 
436 		if (sdrv->shutdown)
437 			sdrv->shutdown(to_spi_device(dev));
438 	}
439 }
440 
441 struct bus_type spi_bus_type = {
442 	.name		= "spi",
443 	.dev_groups	= spi_dev_groups,
444 	.match		= spi_match_device,
445 	.uevent		= spi_uevent,
446 	.probe		= spi_probe,
447 	.remove		= spi_remove,
448 	.shutdown	= spi_shutdown,
449 };
450 EXPORT_SYMBOL_GPL(spi_bus_type);
451 
452 /**
453  * __spi_register_driver - register a SPI driver
454  * @owner: owner module of the driver to register
455  * @sdrv: the driver to register
456  * Context: can sleep
457  *
458  * Return: zero on success, else a negative error code.
459  */
460 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
461 {
462 	sdrv->driver.owner = owner;
463 	sdrv->driver.bus = &spi_bus_type;
464 	return driver_register(&sdrv->driver);
465 }
466 EXPORT_SYMBOL_GPL(__spi_register_driver);
467 
468 /*-------------------------------------------------------------------------*/
469 
470 /* SPI devices should normally not be created by SPI device drivers; that
471  * would make them board-specific.  Similarly with SPI controller drivers.
472  * Device registration normally goes into like arch/.../mach.../board-YYY.c
473  * with other readonly (flashable) information about mainboard devices.
474  */
475 
476 struct boardinfo {
477 	struct list_head	list;
478 	struct spi_board_info	board_info;
479 };
480 
481 static LIST_HEAD(board_list);
482 static LIST_HEAD(spi_controller_list);
483 
484 /*
485  * Used to protect add/del operation for board_info list and
486  * spi_controller list, and their matching process
487  * also used to protect object of type struct idr
488  */
489 static DEFINE_MUTEX(board_lock);
490 
491 /*
492  * Prevents addition of devices with same chip select and
493  * addition of devices below an unregistering controller.
494  */
495 static DEFINE_MUTEX(spi_add_lock);
496 
497 /**
498  * spi_alloc_device - Allocate a new SPI device
499  * @ctlr: Controller to which device is connected
500  * Context: can sleep
501  *
502  * Allows a driver to allocate and initialize a spi_device without
503  * registering it immediately.  This allows a driver to directly
504  * fill the spi_device with device parameters before calling
505  * spi_add_device() on it.
506  *
507  * Caller is responsible to call spi_add_device() on the returned
508  * spi_device structure to add it to the SPI controller.  If the caller
509  * needs to discard the spi_device without adding it, then it should
510  * call spi_dev_put() on it.
511  *
512  * Return: a pointer to the new device, or NULL.
513  */
514 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
515 {
516 	struct spi_device	*spi;
517 
518 	if (!spi_controller_get(ctlr))
519 		return NULL;
520 
521 	spi = kzalloc(sizeof(*spi), GFP_KERNEL);
522 	if (!spi) {
523 		spi_controller_put(ctlr);
524 		return NULL;
525 	}
526 
527 	spi->master = spi->controller = ctlr;
528 	spi->dev.parent = &ctlr->dev;
529 	spi->dev.bus = &spi_bus_type;
530 	spi->dev.release = spidev_release;
531 	spi->cs_gpio = -ENOENT;
532 	spi->mode = ctlr->buswidth_override_bits;
533 
534 	spin_lock_init(&spi->statistics.lock);
535 
536 	device_initialize(&spi->dev);
537 	return spi;
538 }
539 EXPORT_SYMBOL_GPL(spi_alloc_device);
540 
541 static void spi_dev_set_name(struct spi_device *spi)
542 {
543 	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
544 
545 	if (adev) {
546 		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
547 		return;
548 	}
549 
550 	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
551 		     spi->chip_select);
552 }
553 
554 static int spi_dev_check(struct device *dev, void *data)
555 {
556 	struct spi_device *spi = to_spi_device(dev);
557 	struct spi_device *new_spi = data;
558 
559 	if (spi->controller == new_spi->controller &&
560 	    spi->chip_select == new_spi->chip_select)
561 		return -EBUSY;
562 	return 0;
563 }
564 
565 static void spi_cleanup(struct spi_device *spi)
566 {
567 	if (spi->controller->cleanup)
568 		spi->controller->cleanup(spi);
569 }
570 
571 static int __spi_add_device(struct spi_device *spi)
572 {
573 	struct spi_controller *ctlr = spi->controller;
574 	struct device *dev = ctlr->dev.parent;
575 	int status;
576 
577 	status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
578 	if (status) {
579 		dev_err(dev, "chipselect %d already in use\n",
580 				spi->chip_select);
581 		return status;
582 	}
583 
584 	/* Controller may unregister concurrently */
585 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
586 	    !device_is_registered(&ctlr->dev)) {
587 		return -ENODEV;
588 	}
589 
590 	/* Descriptors take precedence */
591 	if (ctlr->cs_gpiods)
592 		spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
593 	else if (ctlr->cs_gpios)
594 		spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
595 
596 	/* Drivers may modify this initial i/o setup, but will
597 	 * normally rely on the device being setup.  Devices
598 	 * using SPI_CS_HIGH can't coexist well otherwise...
599 	 */
600 	status = spi_setup(spi);
601 	if (status < 0) {
602 		dev_err(dev, "can't setup %s, status %d\n",
603 				dev_name(&spi->dev), status);
604 		return status;
605 	}
606 
607 	/* Device may be bound to an active driver when this returns */
608 	status = device_add(&spi->dev);
609 	if (status < 0) {
610 		dev_err(dev, "can't add %s, status %d\n",
611 				dev_name(&spi->dev), status);
612 		spi_cleanup(spi);
613 	} else {
614 		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
615 	}
616 
617 	return status;
618 }
619 
620 /**
621  * spi_add_device - Add spi_device allocated with spi_alloc_device
622  * @spi: spi_device to register
623  *
624  * Companion function to spi_alloc_device.  Devices allocated with
625  * spi_alloc_device can be added onto the spi bus with this function.
626  *
627  * Return: 0 on success; negative errno on failure
628  */
629 int spi_add_device(struct spi_device *spi)
630 {
631 	struct spi_controller *ctlr = spi->controller;
632 	struct device *dev = ctlr->dev.parent;
633 	int status;
634 
635 	/* Chipselects are numbered 0..max; validate. */
636 	if (spi->chip_select >= ctlr->num_chipselect) {
637 		dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
638 			ctlr->num_chipselect);
639 		return -EINVAL;
640 	}
641 
642 	/* Set the bus ID string */
643 	spi_dev_set_name(spi);
644 
645 	/* We need to make sure there's no other device with this
646 	 * chipselect **BEFORE** we call setup(), else we'll trash
647 	 * its configuration.  Lock against concurrent add() calls.
648 	 */
649 	mutex_lock(&spi_add_lock);
650 	status = __spi_add_device(spi);
651 	mutex_unlock(&spi_add_lock);
652 	return status;
653 }
654 EXPORT_SYMBOL_GPL(spi_add_device);
655 
656 static int spi_add_device_locked(struct spi_device *spi)
657 {
658 	struct spi_controller *ctlr = spi->controller;
659 	struct device *dev = ctlr->dev.parent;
660 
661 	/* Chipselects are numbered 0..max; validate. */
662 	if (spi->chip_select >= ctlr->num_chipselect) {
663 		dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
664 			ctlr->num_chipselect);
665 		return -EINVAL;
666 	}
667 
668 	/* Set the bus ID string */
669 	spi_dev_set_name(spi);
670 
671 	WARN_ON(!mutex_is_locked(&spi_add_lock));
672 	return __spi_add_device(spi);
673 }
674 
675 /**
676  * spi_new_device - instantiate one new SPI device
677  * @ctlr: Controller to which device is connected
678  * @chip: Describes the SPI device
679  * Context: can sleep
680  *
681  * On typical mainboards, this is purely internal; and it's not needed
682  * after board init creates the hard-wired devices.  Some development
683  * platforms may not be able to use spi_register_board_info though, and
684  * this is exported so that for example a USB or parport based adapter
685  * driver could add devices (which it would learn about out-of-band).
686  *
687  * Return: the new device, or NULL.
688  */
689 struct spi_device *spi_new_device(struct spi_controller *ctlr,
690 				  struct spi_board_info *chip)
691 {
692 	struct spi_device	*proxy;
693 	int			status;
694 
695 	/* NOTE:  caller did any chip->bus_num checks necessary.
696 	 *
697 	 * Also, unless we change the return value convention to use
698 	 * error-or-pointer (not NULL-or-pointer), troubleshootability
699 	 * suggests syslogged diagnostics are best here (ugh).
700 	 */
701 
702 	proxy = spi_alloc_device(ctlr);
703 	if (!proxy)
704 		return NULL;
705 
706 	WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
707 
708 	proxy->chip_select = chip->chip_select;
709 	proxy->max_speed_hz = chip->max_speed_hz;
710 	proxy->mode = chip->mode;
711 	proxy->irq = chip->irq;
712 	strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
713 	proxy->dev.platform_data = (void *) chip->platform_data;
714 	proxy->controller_data = chip->controller_data;
715 	proxy->controller_state = NULL;
716 
717 	if (chip->swnode) {
718 		status = device_add_software_node(&proxy->dev, chip->swnode);
719 		if (status) {
720 			dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
721 				chip->modalias, status);
722 			goto err_dev_put;
723 		}
724 	}
725 
726 	status = spi_add_device(proxy);
727 	if (status < 0)
728 		goto err_dev_put;
729 
730 	return proxy;
731 
732 err_dev_put:
733 	device_remove_software_node(&proxy->dev);
734 	spi_dev_put(proxy);
735 	return NULL;
736 }
737 EXPORT_SYMBOL_GPL(spi_new_device);
738 
739 /**
740  * spi_unregister_device - unregister a single SPI device
741  * @spi: spi_device to unregister
742  *
743  * Start making the passed SPI device vanish. Normally this would be handled
744  * by spi_unregister_controller().
745  */
746 void spi_unregister_device(struct spi_device *spi)
747 {
748 	if (!spi)
749 		return;
750 
751 	if (spi->dev.of_node) {
752 		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
753 		of_node_put(spi->dev.of_node);
754 	}
755 	if (ACPI_COMPANION(&spi->dev))
756 		acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
757 	device_remove_software_node(&spi->dev);
758 	device_del(&spi->dev);
759 	spi_cleanup(spi);
760 	put_device(&spi->dev);
761 }
762 EXPORT_SYMBOL_GPL(spi_unregister_device);
763 
764 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
765 					      struct spi_board_info *bi)
766 {
767 	struct spi_device *dev;
768 
769 	if (ctlr->bus_num != bi->bus_num)
770 		return;
771 
772 	dev = spi_new_device(ctlr, bi);
773 	if (!dev)
774 		dev_err(ctlr->dev.parent, "can't create new device for %s\n",
775 			bi->modalias);
776 }
777 
778 /**
779  * spi_register_board_info - register SPI devices for a given board
780  * @info: array of chip descriptors
781  * @n: how many descriptors are provided
782  * Context: can sleep
783  *
784  * Board-specific early init code calls this (probably during arch_initcall)
785  * with segments of the SPI device table.  Any device nodes are created later,
786  * after the relevant parent SPI controller (bus_num) is defined.  We keep
787  * this table of devices forever, so that reloading a controller driver will
788  * not make Linux forget about these hard-wired devices.
789  *
790  * Other code can also call this, e.g. a particular add-on board might provide
791  * SPI devices through its expansion connector, so code initializing that board
792  * would naturally declare its SPI devices.
793  *
794  * The board info passed can safely be __initdata ... but be careful of
795  * any embedded pointers (platform_data, etc), they're copied as-is.
796  *
797  * Return: zero on success, else a negative error code.
798  */
799 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
800 {
801 	struct boardinfo *bi;
802 	int i;
803 
804 	if (!n)
805 		return 0;
806 
807 	bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
808 	if (!bi)
809 		return -ENOMEM;
810 
811 	for (i = 0; i < n; i++, bi++, info++) {
812 		struct spi_controller *ctlr;
813 
814 		memcpy(&bi->board_info, info, sizeof(*info));
815 
816 		mutex_lock(&board_lock);
817 		list_add_tail(&bi->list, &board_list);
818 		list_for_each_entry(ctlr, &spi_controller_list, list)
819 			spi_match_controller_to_boardinfo(ctlr,
820 							  &bi->board_info);
821 		mutex_unlock(&board_lock);
822 	}
823 
824 	return 0;
825 }
826 
827 /*-------------------------------------------------------------------------*/
828 
829 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
830 {
831 	bool activate = enable;
832 
833 	/*
834 	 * Avoid calling into the driver (or doing delays) if the chip select
835 	 * isn't actually changing from the last time this was called.
836 	 */
837 	if (!force && (spi->controller->last_cs_enable == enable) &&
838 	    (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
839 		return;
840 
841 	trace_spi_set_cs(spi, activate);
842 
843 	spi->controller->last_cs_enable = enable;
844 	spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
845 
846 	if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
847 	    !spi->controller->set_cs_timing) {
848 		if (activate)
849 			spi_delay_exec(&spi->controller->cs_setup, NULL);
850 		else
851 			spi_delay_exec(&spi->controller->cs_hold, NULL);
852 	}
853 
854 	if (spi->mode & SPI_CS_HIGH)
855 		enable = !enable;
856 
857 	if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
858 		if (!(spi->mode & SPI_NO_CS)) {
859 			if (spi->cs_gpiod) {
860 				/*
861 				 * Historically ACPI has no means of the GPIO polarity and
862 				 * thus the SPISerialBus() resource defines it on the per-chip
863 				 * basis. In order to avoid a chain of negations, the GPIO
864 				 * polarity is considered being Active High. Even for the cases
865 				 * when _DSD() is involved (in the updated versions of ACPI)
866 				 * the GPIO CS polarity must be defined Active High to avoid
867 				 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
868 				 * into account.
869 				 */
870 				if (has_acpi_companion(&spi->dev))
871 					gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
872 				else
873 					/* Polarity handled by GPIO library */
874 					gpiod_set_value_cansleep(spi->cs_gpiod, activate);
875 			} else {
876 				/*
877 				 * invert the enable line, as active low is
878 				 * default for SPI.
879 				 */
880 				gpio_set_value_cansleep(spi->cs_gpio, !enable);
881 			}
882 		}
883 		/* Some SPI masters need both GPIO CS & slave_select */
884 		if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
885 		    spi->controller->set_cs)
886 			spi->controller->set_cs(spi, !enable);
887 	} else if (spi->controller->set_cs) {
888 		spi->controller->set_cs(spi, !enable);
889 	}
890 
891 	if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
892 	    !spi->controller->set_cs_timing) {
893 		if (!activate)
894 			spi_delay_exec(&spi->controller->cs_inactive, NULL);
895 	}
896 }
897 
898 #ifdef CONFIG_HAS_DMA
899 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
900 		struct sg_table *sgt, void *buf, size_t len,
901 		enum dma_data_direction dir)
902 {
903 	const bool vmalloced_buf = is_vmalloc_addr(buf);
904 	unsigned int max_seg_size = dma_get_max_seg_size(dev);
905 #ifdef CONFIG_HIGHMEM
906 	const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
907 				(unsigned long)buf < (PKMAP_BASE +
908 					(LAST_PKMAP * PAGE_SIZE)));
909 #else
910 	const bool kmap_buf = false;
911 #endif
912 	int desc_len;
913 	int sgs;
914 	struct page *vm_page;
915 	struct scatterlist *sg;
916 	void *sg_buf;
917 	size_t min;
918 	int i, ret;
919 
920 	if (vmalloced_buf || kmap_buf) {
921 		desc_len = min_t(int, max_seg_size, PAGE_SIZE);
922 		sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
923 	} else if (virt_addr_valid(buf)) {
924 		desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
925 		sgs = DIV_ROUND_UP(len, desc_len);
926 	} else {
927 		return -EINVAL;
928 	}
929 
930 	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
931 	if (ret != 0)
932 		return ret;
933 
934 	sg = &sgt->sgl[0];
935 	for (i = 0; i < sgs; i++) {
936 
937 		if (vmalloced_buf || kmap_buf) {
938 			/*
939 			 * Next scatterlist entry size is the minimum between
940 			 * the desc_len and the remaining buffer length that
941 			 * fits in a page.
942 			 */
943 			min = min_t(size_t, desc_len,
944 				    min_t(size_t, len,
945 					  PAGE_SIZE - offset_in_page(buf)));
946 			if (vmalloced_buf)
947 				vm_page = vmalloc_to_page(buf);
948 			else
949 				vm_page = kmap_to_page(buf);
950 			if (!vm_page) {
951 				sg_free_table(sgt);
952 				return -ENOMEM;
953 			}
954 			sg_set_page(sg, vm_page,
955 				    min, offset_in_page(buf));
956 		} else {
957 			min = min_t(size_t, len, desc_len);
958 			sg_buf = buf;
959 			sg_set_buf(sg, sg_buf, min);
960 		}
961 
962 		buf += min;
963 		len -= min;
964 		sg = sg_next(sg);
965 	}
966 
967 	ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
968 	if (!ret)
969 		ret = -ENOMEM;
970 	if (ret < 0) {
971 		sg_free_table(sgt);
972 		return ret;
973 	}
974 
975 	sgt->nents = ret;
976 
977 	return 0;
978 }
979 
980 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
981 		   struct sg_table *sgt, enum dma_data_direction dir)
982 {
983 	if (sgt->orig_nents) {
984 		dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
985 		sg_free_table(sgt);
986 	}
987 }
988 
989 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
990 {
991 	struct device *tx_dev, *rx_dev;
992 	struct spi_transfer *xfer;
993 	int ret;
994 
995 	if (!ctlr->can_dma)
996 		return 0;
997 
998 	if (ctlr->dma_tx)
999 		tx_dev = ctlr->dma_tx->device->dev;
1000 	else if (ctlr->dma_map_dev)
1001 		tx_dev = ctlr->dma_map_dev;
1002 	else
1003 		tx_dev = ctlr->dev.parent;
1004 
1005 	if (ctlr->dma_rx)
1006 		rx_dev = ctlr->dma_rx->device->dev;
1007 	else if (ctlr->dma_map_dev)
1008 		rx_dev = ctlr->dma_map_dev;
1009 	else
1010 		rx_dev = ctlr->dev.parent;
1011 
1012 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1013 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1014 			continue;
1015 
1016 		if (xfer->tx_buf != NULL) {
1017 			ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
1018 					  (void *)xfer->tx_buf, xfer->len,
1019 					  DMA_TO_DEVICE);
1020 			if (ret != 0)
1021 				return ret;
1022 		}
1023 
1024 		if (xfer->rx_buf != NULL) {
1025 			ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
1026 					  xfer->rx_buf, xfer->len,
1027 					  DMA_FROM_DEVICE);
1028 			if (ret != 0) {
1029 				spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
1030 					      DMA_TO_DEVICE);
1031 				return ret;
1032 			}
1033 		}
1034 	}
1035 
1036 	ctlr->cur_msg_mapped = true;
1037 
1038 	return 0;
1039 }
1040 
1041 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1042 {
1043 	struct spi_transfer *xfer;
1044 	struct device *tx_dev, *rx_dev;
1045 
1046 	if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1047 		return 0;
1048 
1049 	if (ctlr->dma_tx)
1050 		tx_dev = ctlr->dma_tx->device->dev;
1051 	else
1052 		tx_dev = ctlr->dev.parent;
1053 
1054 	if (ctlr->dma_rx)
1055 		rx_dev = ctlr->dma_rx->device->dev;
1056 	else
1057 		rx_dev = ctlr->dev.parent;
1058 
1059 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1060 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1061 			continue;
1062 
1063 		spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1064 		spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1065 	}
1066 
1067 	ctlr->cur_msg_mapped = false;
1068 
1069 	return 0;
1070 }
1071 #else /* !CONFIG_HAS_DMA */
1072 static inline int __spi_map_msg(struct spi_controller *ctlr,
1073 				struct spi_message *msg)
1074 {
1075 	return 0;
1076 }
1077 
1078 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1079 				  struct spi_message *msg)
1080 {
1081 	return 0;
1082 }
1083 #endif /* !CONFIG_HAS_DMA */
1084 
1085 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1086 				struct spi_message *msg)
1087 {
1088 	struct spi_transfer *xfer;
1089 
1090 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1091 		/*
1092 		 * Restore the original value of tx_buf or rx_buf if they are
1093 		 * NULL.
1094 		 */
1095 		if (xfer->tx_buf == ctlr->dummy_tx)
1096 			xfer->tx_buf = NULL;
1097 		if (xfer->rx_buf == ctlr->dummy_rx)
1098 			xfer->rx_buf = NULL;
1099 	}
1100 
1101 	return __spi_unmap_msg(ctlr, msg);
1102 }
1103 
1104 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1105 {
1106 	struct spi_transfer *xfer;
1107 	void *tmp;
1108 	unsigned int max_tx, max_rx;
1109 
1110 	if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1111 		&& !(msg->spi->mode & SPI_3WIRE)) {
1112 		max_tx = 0;
1113 		max_rx = 0;
1114 
1115 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1116 			if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1117 			    !xfer->tx_buf)
1118 				max_tx = max(xfer->len, max_tx);
1119 			if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1120 			    !xfer->rx_buf)
1121 				max_rx = max(xfer->len, max_rx);
1122 		}
1123 
1124 		if (max_tx) {
1125 			tmp = krealloc(ctlr->dummy_tx, max_tx,
1126 				       GFP_KERNEL | GFP_DMA);
1127 			if (!tmp)
1128 				return -ENOMEM;
1129 			ctlr->dummy_tx = tmp;
1130 			memset(tmp, 0, max_tx);
1131 		}
1132 
1133 		if (max_rx) {
1134 			tmp = krealloc(ctlr->dummy_rx, max_rx,
1135 				       GFP_KERNEL | GFP_DMA);
1136 			if (!tmp)
1137 				return -ENOMEM;
1138 			ctlr->dummy_rx = tmp;
1139 		}
1140 
1141 		if (max_tx || max_rx) {
1142 			list_for_each_entry(xfer, &msg->transfers,
1143 					    transfer_list) {
1144 				if (!xfer->len)
1145 					continue;
1146 				if (!xfer->tx_buf)
1147 					xfer->tx_buf = ctlr->dummy_tx;
1148 				if (!xfer->rx_buf)
1149 					xfer->rx_buf = ctlr->dummy_rx;
1150 			}
1151 		}
1152 	}
1153 
1154 	return __spi_map_msg(ctlr, msg);
1155 }
1156 
1157 static int spi_transfer_wait(struct spi_controller *ctlr,
1158 			     struct spi_message *msg,
1159 			     struct spi_transfer *xfer)
1160 {
1161 	struct spi_statistics *statm = &ctlr->statistics;
1162 	struct spi_statistics *stats = &msg->spi->statistics;
1163 	u32 speed_hz = xfer->speed_hz;
1164 	unsigned long long ms;
1165 
1166 	if (spi_controller_is_slave(ctlr)) {
1167 		if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1168 			dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1169 			return -EINTR;
1170 		}
1171 	} else {
1172 		if (!speed_hz)
1173 			speed_hz = 100000;
1174 
1175 		/*
1176 		 * For each byte we wait for 8 cycles of the SPI clock.
1177 		 * Since speed is defined in Hz and we want milliseconds,
1178 		 * use respective multiplier, but before the division,
1179 		 * otherwise we may get 0 for short transfers.
1180 		 */
1181 		ms = 8LL * MSEC_PER_SEC * xfer->len;
1182 		do_div(ms, speed_hz);
1183 
1184 		/*
1185 		 * Increase it twice and add 200 ms tolerance, use
1186 		 * predefined maximum in case of overflow.
1187 		 */
1188 		ms += ms + 200;
1189 		if (ms > UINT_MAX)
1190 			ms = UINT_MAX;
1191 
1192 		ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1193 						 msecs_to_jiffies(ms));
1194 
1195 		if (ms == 0) {
1196 			SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1197 			SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1198 			dev_err(&msg->spi->dev,
1199 				"SPI transfer timed out\n");
1200 			return -ETIMEDOUT;
1201 		}
1202 	}
1203 
1204 	return 0;
1205 }
1206 
1207 static void _spi_transfer_delay_ns(u32 ns)
1208 {
1209 	if (!ns)
1210 		return;
1211 	if (ns <= NSEC_PER_USEC) {
1212 		ndelay(ns);
1213 	} else {
1214 		u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1215 
1216 		if (us <= 10)
1217 			udelay(us);
1218 		else
1219 			usleep_range(us, us + DIV_ROUND_UP(us, 10));
1220 	}
1221 }
1222 
1223 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1224 {
1225 	u32 delay = _delay->value;
1226 	u32 unit = _delay->unit;
1227 	u32 hz;
1228 
1229 	if (!delay)
1230 		return 0;
1231 
1232 	switch (unit) {
1233 	case SPI_DELAY_UNIT_USECS:
1234 		delay *= NSEC_PER_USEC;
1235 		break;
1236 	case SPI_DELAY_UNIT_NSECS:
1237 		/* Nothing to do here */
1238 		break;
1239 	case SPI_DELAY_UNIT_SCK:
1240 		/* clock cycles need to be obtained from spi_transfer */
1241 		if (!xfer)
1242 			return -EINVAL;
1243 		/*
1244 		 * If there is unknown effective speed, approximate it
1245 		 * by underestimating with half of the requested hz.
1246 		 */
1247 		hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1248 		if (!hz)
1249 			return -EINVAL;
1250 
1251 		/* Convert delay to nanoseconds */
1252 		delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1253 		break;
1254 	default:
1255 		return -EINVAL;
1256 	}
1257 
1258 	return delay;
1259 }
1260 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1261 
1262 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1263 {
1264 	int delay;
1265 
1266 	might_sleep();
1267 
1268 	if (!_delay)
1269 		return -EINVAL;
1270 
1271 	delay = spi_delay_to_ns(_delay, xfer);
1272 	if (delay < 0)
1273 		return delay;
1274 
1275 	_spi_transfer_delay_ns(delay);
1276 
1277 	return 0;
1278 }
1279 EXPORT_SYMBOL_GPL(spi_delay_exec);
1280 
1281 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1282 					  struct spi_transfer *xfer)
1283 {
1284 	u32 default_delay_ns = 10 * NSEC_PER_USEC;
1285 	u32 delay = xfer->cs_change_delay.value;
1286 	u32 unit = xfer->cs_change_delay.unit;
1287 	int ret;
1288 
1289 	/* return early on "fast" mode - for everything but USECS */
1290 	if (!delay) {
1291 		if (unit == SPI_DELAY_UNIT_USECS)
1292 			_spi_transfer_delay_ns(default_delay_ns);
1293 		return;
1294 	}
1295 
1296 	ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1297 	if (ret) {
1298 		dev_err_once(&msg->spi->dev,
1299 			     "Use of unsupported delay unit %i, using default of %luus\n",
1300 			     unit, default_delay_ns / NSEC_PER_USEC);
1301 		_spi_transfer_delay_ns(default_delay_ns);
1302 	}
1303 }
1304 
1305 /*
1306  * spi_transfer_one_message - Default implementation of transfer_one_message()
1307  *
1308  * This is a standard implementation of transfer_one_message() for
1309  * drivers which implement a transfer_one() operation.  It provides
1310  * standard handling of delays and chip select management.
1311  */
1312 static int spi_transfer_one_message(struct spi_controller *ctlr,
1313 				    struct spi_message *msg)
1314 {
1315 	struct spi_transfer *xfer;
1316 	bool keep_cs = false;
1317 	int ret = 0;
1318 	struct spi_statistics *statm = &ctlr->statistics;
1319 	struct spi_statistics *stats = &msg->spi->statistics;
1320 
1321 	spi_set_cs(msg->spi, true, false);
1322 
1323 	SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1324 	SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1325 
1326 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1327 		trace_spi_transfer_start(msg, xfer);
1328 
1329 		spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1330 		spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1331 
1332 		if (!ctlr->ptp_sts_supported) {
1333 			xfer->ptp_sts_word_pre = 0;
1334 			ptp_read_system_prets(xfer->ptp_sts);
1335 		}
1336 
1337 		if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1338 			reinit_completion(&ctlr->xfer_completion);
1339 
1340 fallback_pio:
1341 			ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1342 			if (ret < 0) {
1343 				if (ctlr->cur_msg_mapped &&
1344 				   (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1345 					__spi_unmap_msg(ctlr, msg);
1346 					ctlr->fallback = true;
1347 					xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1348 					goto fallback_pio;
1349 				}
1350 
1351 				SPI_STATISTICS_INCREMENT_FIELD(statm,
1352 							       errors);
1353 				SPI_STATISTICS_INCREMENT_FIELD(stats,
1354 							       errors);
1355 				dev_err(&msg->spi->dev,
1356 					"SPI transfer failed: %d\n", ret);
1357 				goto out;
1358 			}
1359 
1360 			if (ret > 0) {
1361 				ret = spi_transfer_wait(ctlr, msg, xfer);
1362 				if (ret < 0)
1363 					msg->status = ret;
1364 			}
1365 		} else {
1366 			if (xfer->len)
1367 				dev_err(&msg->spi->dev,
1368 					"Bufferless transfer has length %u\n",
1369 					xfer->len);
1370 		}
1371 
1372 		if (!ctlr->ptp_sts_supported) {
1373 			ptp_read_system_postts(xfer->ptp_sts);
1374 			xfer->ptp_sts_word_post = xfer->len;
1375 		}
1376 
1377 		trace_spi_transfer_stop(msg, xfer);
1378 
1379 		if (msg->status != -EINPROGRESS)
1380 			goto out;
1381 
1382 		spi_transfer_delay_exec(xfer);
1383 
1384 		if (xfer->cs_change) {
1385 			if (list_is_last(&xfer->transfer_list,
1386 					 &msg->transfers)) {
1387 				keep_cs = true;
1388 			} else {
1389 				spi_set_cs(msg->spi, false, false);
1390 				_spi_transfer_cs_change_delay(msg, xfer);
1391 				spi_set_cs(msg->spi, true, false);
1392 			}
1393 		}
1394 
1395 		msg->actual_length += xfer->len;
1396 	}
1397 
1398 out:
1399 	if (ret != 0 || !keep_cs)
1400 		spi_set_cs(msg->spi, false, false);
1401 
1402 	if (msg->status == -EINPROGRESS)
1403 		msg->status = ret;
1404 
1405 	if (msg->status && ctlr->handle_err)
1406 		ctlr->handle_err(ctlr, msg);
1407 
1408 	spi_finalize_current_message(ctlr);
1409 
1410 	return ret;
1411 }
1412 
1413 /**
1414  * spi_finalize_current_transfer - report completion of a transfer
1415  * @ctlr: the controller reporting completion
1416  *
1417  * Called by SPI drivers using the core transfer_one_message()
1418  * implementation to notify it that the current interrupt driven
1419  * transfer has finished and the next one may be scheduled.
1420  */
1421 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1422 {
1423 	complete(&ctlr->xfer_completion);
1424 }
1425 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1426 
1427 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1428 {
1429 	if (ctlr->auto_runtime_pm) {
1430 		pm_runtime_mark_last_busy(ctlr->dev.parent);
1431 		pm_runtime_put_autosuspend(ctlr->dev.parent);
1432 	}
1433 }
1434 
1435 /**
1436  * __spi_pump_messages - function which processes spi message queue
1437  * @ctlr: controller to process queue for
1438  * @in_kthread: true if we are in the context of the message pump thread
1439  *
1440  * This function checks if there is any spi message in the queue that
1441  * needs processing and if so call out to the driver to initialize hardware
1442  * and transfer each message.
1443  *
1444  * Note that it is called both from the kthread itself and also from
1445  * inside spi_sync(); the queue extraction handling at the top of the
1446  * function should deal with this safely.
1447  */
1448 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1449 {
1450 	struct spi_transfer *xfer;
1451 	struct spi_message *msg;
1452 	bool was_busy = false;
1453 	unsigned long flags;
1454 	int ret;
1455 
1456 	/* Lock queue */
1457 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1458 
1459 	/* Make sure we are not already running a message */
1460 	if (ctlr->cur_msg) {
1461 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1462 		return;
1463 	}
1464 
1465 	/* If another context is idling the device then defer */
1466 	if (ctlr->idling) {
1467 		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1468 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1469 		return;
1470 	}
1471 
1472 	/* Check if the queue is idle */
1473 	if (list_empty(&ctlr->queue) || !ctlr->running) {
1474 		if (!ctlr->busy) {
1475 			spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1476 			return;
1477 		}
1478 
1479 		/* Defer any non-atomic teardown to the thread */
1480 		if (!in_kthread) {
1481 			if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1482 			    !ctlr->unprepare_transfer_hardware) {
1483 				spi_idle_runtime_pm(ctlr);
1484 				ctlr->busy = false;
1485 				trace_spi_controller_idle(ctlr);
1486 			} else {
1487 				kthread_queue_work(ctlr->kworker,
1488 						   &ctlr->pump_messages);
1489 			}
1490 			spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1491 			return;
1492 		}
1493 
1494 		ctlr->busy = false;
1495 		ctlr->idling = true;
1496 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1497 
1498 		kfree(ctlr->dummy_rx);
1499 		ctlr->dummy_rx = NULL;
1500 		kfree(ctlr->dummy_tx);
1501 		ctlr->dummy_tx = NULL;
1502 		if (ctlr->unprepare_transfer_hardware &&
1503 		    ctlr->unprepare_transfer_hardware(ctlr))
1504 			dev_err(&ctlr->dev,
1505 				"failed to unprepare transfer hardware\n");
1506 		spi_idle_runtime_pm(ctlr);
1507 		trace_spi_controller_idle(ctlr);
1508 
1509 		spin_lock_irqsave(&ctlr->queue_lock, flags);
1510 		ctlr->idling = false;
1511 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1512 		return;
1513 	}
1514 
1515 	/* Extract head of queue */
1516 	msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1517 	ctlr->cur_msg = msg;
1518 
1519 	list_del_init(&msg->queue);
1520 	if (ctlr->busy)
1521 		was_busy = true;
1522 	else
1523 		ctlr->busy = true;
1524 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1525 
1526 	mutex_lock(&ctlr->io_mutex);
1527 
1528 	if (!was_busy && ctlr->auto_runtime_pm) {
1529 		ret = pm_runtime_get_sync(ctlr->dev.parent);
1530 		if (ret < 0) {
1531 			pm_runtime_put_noidle(ctlr->dev.parent);
1532 			dev_err(&ctlr->dev, "Failed to power device: %d\n",
1533 				ret);
1534 			mutex_unlock(&ctlr->io_mutex);
1535 			return;
1536 		}
1537 	}
1538 
1539 	if (!was_busy)
1540 		trace_spi_controller_busy(ctlr);
1541 
1542 	if (!was_busy && ctlr->prepare_transfer_hardware) {
1543 		ret = ctlr->prepare_transfer_hardware(ctlr);
1544 		if (ret) {
1545 			dev_err(&ctlr->dev,
1546 				"failed to prepare transfer hardware: %d\n",
1547 				ret);
1548 
1549 			if (ctlr->auto_runtime_pm)
1550 				pm_runtime_put(ctlr->dev.parent);
1551 
1552 			msg->status = ret;
1553 			spi_finalize_current_message(ctlr);
1554 
1555 			mutex_unlock(&ctlr->io_mutex);
1556 			return;
1557 		}
1558 	}
1559 
1560 	trace_spi_message_start(msg);
1561 
1562 	if (ctlr->prepare_message) {
1563 		ret = ctlr->prepare_message(ctlr, msg);
1564 		if (ret) {
1565 			dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1566 				ret);
1567 			msg->status = ret;
1568 			spi_finalize_current_message(ctlr);
1569 			goto out;
1570 		}
1571 		ctlr->cur_msg_prepared = true;
1572 	}
1573 
1574 	ret = spi_map_msg(ctlr, msg);
1575 	if (ret) {
1576 		msg->status = ret;
1577 		spi_finalize_current_message(ctlr);
1578 		goto out;
1579 	}
1580 
1581 	if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1582 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1583 			xfer->ptp_sts_word_pre = 0;
1584 			ptp_read_system_prets(xfer->ptp_sts);
1585 		}
1586 	}
1587 
1588 	ret = ctlr->transfer_one_message(ctlr, msg);
1589 	if (ret) {
1590 		dev_err(&ctlr->dev,
1591 			"failed to transfer one message from queue\n");
1592 		goto out;
1593 	}
1594 
1595 out:
1596 	mutex_unlock(&ctlr->io_mutex);
1597 
1598 	/* Prod the scheduler in case transfer_one() was busy waiting */
1599 	if (!ret)
1600 		cond_resched();
1601 }
1602 
1603 /**
1604  * spi_pump_messages - kthread work function which processes spi message queue
1605  * @work: pointer to kthread work struct contained in the controller struct
1606  */
1607 static void spi_pump_messages(struct kthread_work *work)
1608 {
1609 	struct spi_controller *ctlr =
1610 		container_of(work, struct spi_controller, pump_messages);
1611 
1612 	__spi_pump_messages(ctlr, true);
1613 }
1614 
1615 /**
1616  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1617  *			    TX timestamp for the requested byte from the SPI
1618  *			    transfer. The frequency with which this function
1619  *			    must be called (once per word, once for the whole
1620  *			    transfer, once per batch of words etc) is arbitrary
1621  *			    as long as the @tx buffer offset is greater than or
1622  *			    equal to the requested byte at the time of the
1623  *			    call. The timestamp is only taken once, at the
1624  *			    first such call. It is assumed that the driver
1625  *			    advances its @tx buffer pointer monotonically.
1626  * @ctlr: Pointer to the spi_controller structure of the driver
1627  * @xfer: Pointer to the transfer being timestamped
1628  * @progress: How many words (not bytes) have been transferred so far
1629  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1630  *	      transfer, for less jitter in time measurement. Only compatible
1631  *	      with PIO drivers. If true, must follow up with
1632  *	      spi_take_timestamp_post or otherwise system will crash.
1633  *	      WARNING: for fully predictable results, the CPU frequency must
1634  *	      also be under control (governor).
1635  */
1636 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1637 			    struct spi_transfer *xfer,
1638 			    size_t progress, bool irqs_off)
1639 {
1640 	if (!xfer->ptp_sts)
1641 		return;
1642 
1643 	if (xfer->timestamped)
1644 		return;
1645 
1646 	if (progress > xfer->ptp_sts_word_pre)
1647 		return;
1648 
1649 	/* Capture the resolution of the timestamp */
1650 	xfer->ptp_sts_word_pre = progress;
1651 
1652 	if (irqs_off) {
1653 		local_irq_save(ctlr->irq_flags);
1654 		preempt_disable();
1655 	}
1656 
1657 	ptp_read_system_prets(xfer->ptp_sts);
1658 }
1659 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1660 
1661 /**
1662  * spi_take_timestamp_post - helper for drivers to collect the end of the
1663  *			     TX timestamp for the requested byte from the SPI
1664  *			     transfer. Can be called with an arbitrary
1665  *			     frequency: only the first call where @tx exceeds
1666  *			     or is equal to the requested word will be
1667  *			     timestamped.
1668  * @ctlr: Pointer to the spi_controller structure of the driver
1669  * @xfer: Pointer to the transfer being timestamped
1670  * @progress: How many words (not bytes) have been transferred so far
1671  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1672  */
1673 void spi_take_timestamp_post(struct spi_controller *ctlr,
1674 			     struct spi_transfer *xfer,
1675 			     size_t progress, bool irqs_off)
1676 {
1677 	if (!xfer->ptp_sts)
1678 		return;
1679 
1680 	if (xfer->timestamped)
1681 		return;
1682 
1683 	if (progress < xfer->ptp_sts_word_post)
1684 		return;
1685 
1686 	ptp_read_system_postts(xfer->ptp_sts);
1687 
1688 	if (irqs_off) {
1689 		local_irq_restore(ctlr->irq_flags);
1690 		preempt_enable();
1691 	}
1692 
1693 	/* Capture the resolution of the timestamp */
1694 	xfer->ptp_sts_word_post = progress;
1695 
1696 	xfer->timestamped = true;
1697 }
1698 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1699 
1700 /**
1701  * spi_set_thread_rt - set the controller to pump at realtime priority
1702  * @ctlr: controller to boost priority of
1703  *
1704  * This can be called because the controller requested realtime priority
1705  * (by setting the ->rt value before calling spi_register_controller()) or
1706  * because a device on the bus said that its transfers needed realtime
1707  * priority.
1708  *
1709  * NOTE: at the moment if any device on a bus says it needs realtime then
1710  * the thread will be at realtime priority for all transfers on that
1711  * controller.  If this eventually becomes a problem we may see if we can
1712  * find a way to boost the priority only temporarily during relevant
1713  * transfers.
1714  */
1715 static void spi_set_thread_rt(struct spi_controller *ctlr)
1716 {
1717 	dev_info(&ctlr->dev,
1718 		"will run message pump with realtime priority\n");
1719 	sched_set_fifo(ctlr->kworker->task);
1720 }
1721 
1722 static int spi_init_queue(struct spi_controller *ctlr)
1723 {
1724 	ctlr->running = false;
1725 	ctlr->busy = false;
1726 
1727 	ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1728 	if (IS_ERR(ctlr->kworker)) {
1729 		dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1730 		return PTR_ERR(ctlr->kworker);
1731 	}
1732 
1733 	kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1734 
1735 	/*
1736 	 * Controller config will indicate if this controller should run the
1737 	 * message pump with high (realtime) priority to reduce the transfer
1738 	 * latency on the bus by minimising the delay between a transfer
1739 	 * request and the scheduling of the message pump thread. Without this
1740 	 * setting the message pump thread will remain at default priority.
1741 	 */
1742 	if (ctlr->rt)
1743 		spi_set_thread_rt(ctlr);
1744 
1745 	return 0;
1746 }
1747 
1748 /**
1749  * spi_get_next_queued_message() - called by driver to check for queued
1750  * messages
1751  * @ctlr: the controller to check for queued messages
1752  *
1753  * If there are more messages in the queue, the next message is returned from
1754  * this call.
1755  *
1756  * Return: the next message in the queue, else NULL if the queue is empty.
1757  */
1758 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1759 {
1760 	struct spi_message *next;
1761 	unsigned long flags;
1762 
1763 	/* get a pointer to the next message, if any */
1764 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1765 	next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1766 					queue);
1767 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1768 
1769 	return next;
1770 }
1771 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1772 
1773 /**
1774  * spi_finalize_current_message() - the current message is complete
1775  * @ctlr: the controller to return the message to
1776  *
1777  * Called by the driver to notify the core that the message in the front of the
1778  * queue is complete and can be removed from the queue.
1779  */
1780 void spi_finalize_current_message(struct spi_controller *ctlr)
1781 {
1782 	struct spi_transfer *xfer;
1783 	struct spi_message *mesg;
1784 	unsigned long flags;
1785 	int ret;
1786 
1787 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1788 	mesg = ctlr->cur_msg;
1789 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1790 
1791 	if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1792 		list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1793 			ptp_read_system_postts(xfer->ptp_sts);
1794 			xfer->ptp_sts_word_post = xfer->len;
1795 		}
1796 	}
1797 
1798 	if (unlikely(ctlr->ptp_sts_supported))
1799 		list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1800 			WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1801 
1802 	spi_unmap_msg(ctlr, mesg);
1803 
1804 	/* In the prepare_messages callback the spi bus has the opportunity to
1805 	 * split a transfer to smaller chunks.
1806 	 * Release splited transfers here since spi_map_msg is done on the
1807 	 * splited transfers.
1808 	 */
1809 	spi_res_release(ctlr, mesg);
1810 
1811 	if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1812 		ret = ctlr->unprepare_message(ctlr, mesg);
1813 		if (ret) {
1814 			dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1815 				ret);
1816 		}
1817 	}
1818 
1819 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1820 	ctlr->cur_msg = NULL;
1821 	ctlr->cur_msg_prepared = false;
1822 	ctlr->fallback = false;
1823 	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1824 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1825 
1826 	trace_spi_message_done(mesg);
1827 
1828 	mesg->state = NULL;
1829 	if (mesg->complete)
1830 		mesg->complete(mesg->context);
1831 }
1832 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1833 
1834 static int spi_start_queue(struct spi_controller *ctlr)
1835 {
1836 	unsigned long flags;
1837 
1838 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1839 
1840 	if (ctlr->running || ctlr->busy) {
1841 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1842 		return -EBUSY;
1843 	}
1844 
1845 	ctlr->running = true;
1846 	ctlr->cur_msg = NULL;
1847 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1848 
1849 	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1850 
1851 	return 0;
1852 }
1853 
1854 static int spi_stop_queue(struct spi_controller *ctlr)
1855 {
1856 	unsigned long flags;
1857 	unsigned limit = 500;
1858 	int ret = 0;
1859 
1860 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1861 
1862 	/*
1863 	 * This is a bit lame, but is optimized for the common execution path.
1864 	 * A wait_queue on the ctlr->busy could be used, but then the common
1865 	 * execution path (pump_messages) would be required to call wake_up or
1866 	 * friends on every SPI message. Do this instead.
1867 	 */
1868 	while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1869 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1870 		usleep_range(10000, 11000);
1871 		spin_lock_irqsave(&ctlr->queue_lock, flags);
1872 	}
1873 
1874 	if (!list_empty(&ctlr->queue) || ctlr->busy)
1875 		ret = -EBUSY;
1876 	else
1877 		ctlr->running = false;
1878 
1879 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1880 
1881 	if (ret) {
1882 		dev_warn(&ctlr->dev, "could not stop message queue\n");
1883 		return ret;
1884 	}
1885 	return ret;
1886 }
1887 
1888 static int spi_destroy_queue(struct spi_controller *ctlr)
1889 {
1890 	int ret;
1891 
1892 	ret = spi_stop_queue(ctlr);
1893 
1894 	/*
1895 	 * kthread_flush_worker will block until all work is done.
1896 	 * If the reason that stop_queue timed out is that the work will never
1897 	 * finish, then it does no good to call flush/stop thread, so
1898 	 * return anyway.
1899 	 */
1900 	if (ret) {
1901 		dev_err(&ctlr->dev, "problem destroying queue\n");
1902 		return ret;
1903 	}
1904 
1905 	kthread_destroy_worker(ctlr->kworker);
1906 
1907 	return 0;
1908 }
1909 
1910 static int __spi_queued_transfer(struct spi_device *spi,
1911 				 struct spi_message *msg,
1912 				 bool need_pump)
1913 {
1914 	struct spi_controller *ctlr = spi->controller;
1915 	unsigned long flags;
1916 
1917 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1918 
1919 	if (!ctlr->running) {
1920 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1921 		return -ESHUTDOWN;
1922 	}
1923 	msg->actual_length = 0;
1924 	msg->status = -EINPROGRESS;
1925 
1926 	list_add_tail(&msg->queue, &ctlr->queue);
1927 	if (!ctlr->busy && need_pump)
1928 		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1929 
1930 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1931 	return 0;
1932 }
1933 
1934 /**
1935  * spi_queued_transfer - transfer function for queued transfers
1936  * @spi: spi device which is requesting transfer
1937  * @msg: spi message which is to handled is queued to driver queue
1938  *
1939  * Return: zero on success, else a negative error code.
1940  */
1941 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1942 {
1943 	return __spi_queued_transfer(spi, msg, true);
1944 }
1945 
1946 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1947 {
1948 	int ret;
1949 
1950 	ctlr->transfer = spi_queued_transfer;
1951 	if (!ctlr->transfer_one_message)
1952 		ctlr->transfer_one_message = spi_transfer_one_message;
1953 
1954 	/* Initialize and start queue */
1955 	ret = spi_init_queue(ctlr);
1956 	if (ret) {
1957 		dev_err(&ctlr->dev, "problem initializing queue\n");
1958 		goto err_init_queue;
1959 	}
1960 	ctlr->queued = true;
1961 	ret = spi_start_queue(ctlr);
1962 	if (ret) {
1963 		dev_err(&ctlr->dev, "problem starting queue\n");
1964 		goto err_start_queue;
1965 	}
1966 
1967 	return 0;
1968 
1969 err_start_queue:
1970 	spi_destroy_queue(ctlr);
1971 err_init_queue:
1972 	return ret;
1973 }
1974 
1975 /**
1976  * spi_flush_queue - Send all pending messages in the queue from the callers'
1977  *		     context
1978  * @ctlr: controller to process queue for
1979  *
1980  * This should be used when one wants to ensure all pending messages have been
1981  * sent before doing something. Is used by the spi-mem code to make sure SPI
1982  * memory operations do not preempt regular SPI transfers that have been queued
1983  * before the spi-mem operation.
1984  */
1985 void spi_flush_queue(struct spi_controller *ctlr)
1986 {
1987 	if (ctlr->transfer == spi_queued_transfer)
1988 		__spi_pump_messages(ctlr, false);
1989 }
1990 
1991 /*-------------------------------------------------------------------------*/
1992 
1993 #if defined(CONFIG_OF)
1994 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1995 			   struct device_node *nc)
1996 {
1997 	u32 value;
1998 	int rc;
1999 
2000 	/* Mode (clock phase/polarity/etc.) */
2001 	if (of_property_read_bool(nc, "spi-cpha"))
2002 		spi->mode |= SPI_CPHA;
2003 	if (of_property_read_bool(nc, "spi-cpol"))
2004 		spi->mode |= SPI_CPOL;
2005 	if (of_property_read_bool(nc, "spi-3wire"))
2006 		spi->mode |= SPI_3WIRE;
2007 	if (of_property_read_bool(nc, "spi-lsb-first"))
2008 		spi->mode |= SPI_LSB_FIRST;
2009 	if (of_property_read_bool(nc, "spi-cs-high"))
2010 		spi->mode |= SPI_CS_HIGH;
2011 
2012 	/* Device DUAL/QUAD mode */
2013 	if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2014 		switch (value) {
2015 		case 0:
2016 			spi->mode |= SPI_NO_TX;
2017 			break;
2018 		case 1:
2019 			break;
2020 		case 2:
2021 			spi->mode |= SPI_TX_DUAL;
2022 			break;
2023 		case 4:
2024 			spi->mode |= SPI_TX_QUAD;
2025 			break;
2026 		case 8:
2027 			spi->mode |= SPI_TX_OCTAL;
2028 			break;
2029 		default:
2030 			dev_warn(&ctlr->dev,
2031 				"spi-tx-bus-width %d not supported\n",
2032 				value);
2033 			break;
2034 		}
2035 	}
2036 
2037 	if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2038 		switch (value) {
2039 		case 0:
2040 			spi->mode |= SPI_NO_RX;
2041 			break;
2042 		case 1:
2043 			break;
2044 		case 2:
2045 			spi->mode |= SPI_RX_DUAL;
2046 			break;
2047 		case 4:
2048 			spi->mode |= SPI_RX_QUAD;
2049 			break;
2050 		case 8:
2051 			spi->mode |= SPI_RX_OCTAL;
2052 			break;
2053 		default:
2054 			dev_warn(&ctlr->dev,
2055 				"spi-rx-bus-width %d not supported\n",
2056 				value);
2057 			break;
2058 		}
2059 	}
2060 
2061 	if (spi_controller_is_slave(ctlr)) {
2062 		if (!of_node_name_eq(nc, "slave")) {
2063 			dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2064 				nc);
2065 			return -EINVAL;
2066 		}
2067 		return 0;
2068 	}
2069 
2070 	/* Device address */
2071 	rc = of_property_read_u32(nc, "reg", &value);
2072 	if (rc) {
2073 		dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2074 			nc, rc);
2075 		return rc;
2076 	}
2077 	spi->chip_select = value;
2078 
2079 	/* Device speed */
2080 	if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2081 		spi->max_speed_hz = value;
2082 
2083 	return 0;
2084 }
2085 
2086 static struct spi_device *
2087 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2088 {
2089 	struct spi_device *spi;
2090 	int rc;
2091 
2092 	/* Alloc an spi_device */
2093 	spi = spi_alloc_device(ctlr);
2094 	if (!spi) {
2095 		dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2096 		rc = -ENOMEM;
2097 		goto err_out;
2098 	}
2099 
2100 	/* Select device driver */
2101 	rc = of_modalias_node(nc, spi->modalias,
2102 				sizeof(spi->modalias));
2103 	if (rc < 0) {
2104 		dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2105 		goto err_out;
2106 	}
2107 
2108 	rc = of_spi_parse_dt(ctlr, spi, nc);
2109 	if (rc)
2110 		goto err_out;
2111 
2112 	/* Store a pointer to the node in the device structure */
2113 	of_node_get(nc);
2114 	spi->dev.of_node = nc;
2115 	spi->dev.fwnode = of_fwnode_handle(nc);
2116 
2117 	/* Register the new device */
2118 	rc = spi_add_device(spi);
2119 	if (rc) {
2120 		dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2121 		goto err_of_node_put;
2122 	}
2123 
2124 	return spi;
2125 
2126 err_of_node_put:
2127 	of_node_put(nc);
2128 err_out:
2129 	spi_dev_put(spi);
2130 	return ERR_PTR(rc);
2131 }
2132 
2133 /**
2134  * of_register_spi_devices() - Register child devices onto the SPI bus
2135  * @ctlr:	Pointer to spi_controller device
2136  *
2137  * Registers an spi_device for each child node of controller node which
2138  * represents a valid SPI slave.
2139  */
2140 static void of_register_spi_devices(struct spi_controller *ctlr)
2141 {
2142 	struct spi_device *spi;
2143 	struct device_node *nc;
2144 
2145 	if (!ctlr->dev.of_node)
2146 		return;
2147 
2148 	for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2149 		if (of_node_test_and_set_flag(nc, OF_POPULATED))
2150 			continue;
2151 		spi = of_register_spi_device(ctlr, nc);
2152 		if (IS_ERR(spi)) {
2153 			dev_warn(&ctlr->dev,
2154 				 "Failed to create SPI device for %pOF\n", nc);
2155 			of_node_clear_flag(nc, OF_POPULATED);
2156 		}
2157 	}
2158 }
2159 #else
2160 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2161 #endif
2162 
2163 /**
2164  * spi_new_ancillary_device() - Register ancillary SPI device
2165  * @spi:         Pointer to the main SPI device registering the ancillary device
2166  * @chip_select: Chip Select of the ancillary device
2167  *
2168  * Register an ancillary SPI device; for example some chips have a chip-select
2169  * for normal device usage and another one for setup/firmware upload.
2170  *
2171  * This may only be called from main SPI device's probe routine.
2172  *
2173  * Return: 0 on success; negative errno on failure
2174  */
2175 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2176 					     u8 chip_select)
2177 {
2178 	struct spi_device *ancillary;
2179 	int rc = 0;
2180 
2181 	/* Alloc an spi_device */
2182 	ancillary = spi_alloc_device(spi->controller);
2183 	if (!ancillary) {
2184 		rc = -ENOMEM;
2185 		goto err_out;
2186 	}
2187 
2188 	strlcpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2189 
2190 	/* Use provided chip-select for ancillary device */
2191 	ancillary->chip_select = chip_select;
2192 
2193 	/* Take over SPI mode/speed from SPI main device */
2194 	ancillary->max_speed_hz = spi->max_speed_hz;
2195 	ancillary->mode = spi->mode;
2196 
2197 	/* Register the new device */
2198 	rc = spi_add_device_locked(ancillary);
2199 	if (rc) {
2200 		dev_err(&spi->dev, "failed to register ancillary device\n");
2201 		goto err_out;
2202 	}
2203 
2204 	return ancillary;
2205 
2206 err_out:
2207 	spi_dev_put(ancillary);
2208 	return ERR_PTR(rc);
2209 }
2210 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2211 
2212 #ifdef CONFIG_ACPI
2213 struct acpi_spi_lookup {
2214 	struct spi_controller 	*ctlr;
2215 	u32			max_speed_hz;
2216 	u32			mode;
2217 	int			irq;
2218 	u8			bits_per_word;
2219 	u8			chip_select;
2220 };
2221 
2222 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2223 					    struct acpi_spi_lookup *lookup)
2224 {
2225 	const union acpi_object *obj;
2226 
2227 	if (!x86_apple_machine)
2228 		return;
2229 
2230 	if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2231 	    && obj->buffer.length >= 4)
2232 		lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2233 
2234 	if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2235 	    && obj->buffer.length == 8)
2236 		lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2237 
2238 	if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2239 	    && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2240 		lookup->mode |= SPI_LSB_FIRST;
2241 
2242 	if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2243 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2244 		lookup->mode |= SPI_CPOL;
2245 
2246 	if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2247 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2248 		lookup->mode |= SPI_CPHA;
2249 }
2250 
2251 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2252 {
2253 	struct acpi_spi_lookup *lookup = data;
2254 	struct spi_controller *ctlr = lookup->ctlr;
2255 
2256 	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2257 		struct acpi_resource_spi_serialbus *sb;
2258 		acpi_handle parent_handle;
2259 		acpi_status status;
2260 
2261 		sb = &ares->data.spi_serial_bus;
2262 		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2263 
2264 			status = acpi_get_handle(NULL,
2265 						 sb->resource_source.string_ptr,
2266 						 &parent_handle);
2267 
2268 			if (ACPI_FAILURE(status) ||
2269 			    ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2270 				return -ENODEV;
2271 
2272 			/*
2273 			 * ACPI DeviceSelection numbering is handled by the
2274 			 * host controller driver in Windows and can vary
2275 			 * from driver to driver. In Linux we always expect
2276 			 * 0 .. max - 1 so we need to ask the driver to
2277 			 * translate between the two schemes.
2278 			 */
2279 			if (ctlr->fw_translate_cs) {
2280 				int cs = ctlr->fw_translate_cs(ctlr,
2281 						sb->device_selection);
2282 				if (cs < 0)
2283 					return cs;
2284 				lookup->chip_select = cs;
2285 			} else {
2286 				lookup->chip_select = sb->device_selection;
2287 			}
2288 
2289 			lookup->max_speed_hz = sb->connection_speed;
2290 			lookup->bits_per_word = sb->data_bit_length;
2291 
2292 			if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2293 				lookup->mode |= SPI_CPHA;
2294 			if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2295 				lookup->mode |= SPI_CPOL;
2296 			if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2297 				lookup->mode |= SPI_CS_HIGH;
2298 		}
2299 	} else if (lookup->irq < 0) {
2300 		struct resource r;
2301 
2302 		if (acpi_dev_resource_interrupt(ares, 0, &r))
2303 			lookup->irq = r.start;
2304 	}
2305 
2306 	/* Always tell the ACPI core to skip this resource */
2307 	return 1;
2308 }
2309 
2310 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2311 					    struct acpi_device *adev)
2312 {
2313 	acpi_handle parent_handle = NULL;
2314 	struct list_head resource_list;
2315 	struct acpi_spi_lookup lookup = {};
2316 	struct spi_device *spi;
2317 	int ret;
2318 
2319 	if (acpi_bus_get_status(adev) || !adev->status.present ||
2320 	    acpi_device_enumerated(adev))
2321 		return AE_OK;
2322 
2323 	lookup.ctlr		= ctlr;
2324 	lookup.irq		= -1;
2325 
2326 	INIT_LIST_HEAD(&resource_list);
2327 	ret = acpi_dev_get_resources(adev, &resource_list,
2328 				     acpi_spi_add_resource, &lookup);
2329 	acpi_dev_free_resource_list(&resource_list);
2330 
2331 	if (ret < 0)
2332 		/* found SPI in _CRS but it points to another controller */
2333 		return AE_OK;
2334 
2335 	if (!lookup.max_speed_hz &&
2336 	    ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2337 	    ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2338 		/* Apple does not use _CRS but nested devices for SPI slaves */
2339 		acpi_spi_parse_apple_properties(adev, &lookup);
2340 	}
2341 
2342 	if (!lookup.max_speed_hz)
2343 		return AE_OK;
2344 
2345 	spi = spi_alloc_device(ctlr);
2346 	if (!spi) {
2347 		dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2348 			dev_name(&adev->dev));
2349 		return AE_NO_MEMORY;
2350 	}
2351 
2352 
2353 	ACPI_COMPANION_SET(&spi->dev, adev);
2354 	spi->max_speed_hz	= lookup.max_speed_hz;
2355 	spi->mode		|= lookup.mode;
2356 	spi->irq		= lookup.irq;
2357 	spi->bits_per_word	= lookup.bits_per_word;
2358 	spi->chip_select	= lookup.chip_select;
2359 
2360 	acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2361 			  sizeof(spi->modalias));
2362 
2363 	if (spi->irq < 0)
2364 		spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2365 
2366 	acpi_device_set_enumerated(adev);
2367 
2368 	adev->power.flags.ignore_parent = true;
2369 	if (spi_add_device(spi)) {
2370 		adev->power.flags.ignore_parent = false;
2371 		dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2372 			dev_name(&adev->dev));
2373 		spi_dev_put(spi);
2374 	}
2375 
2376 	return AE_OK;
2377 }
2378 
2379 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2380 				       void *data, void **return_value)
2381 {
2382 	struct spi_controller *ctlr = data;
2383 	struct acpi_device *adev;
2384 
2385 	if (acpi_bus_get_device(handle, &adev))
2386 		return AE_OK;
2387 
2388 	return acpi_register_spi_device(ctlr, adev);
2389 }
2390 
2391 #define SPI_ACPI_ENUMERATE_MAX_DEPTH		32
2392 
2393 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2394 {
2395 	acpi_status status;
2396 	acpi_handle handle;
2397 
2398 	handle = ACPI_HANDLE(ctlr->dev.parent);
2399 	if (!handle)
2400 		return;
2401 
2402 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2403 				     SPI_ACPI_ENUMERATE_MAX_DEPTH,
2404 				     acpi_spi_add_device, NULL, ctlr, NULL);
2405 	if (ACPI_FAILURE(status))
2406 		dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2407 }
2408 #else
2409 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2410 #endif /* CONFIG_ACPI */
2411 
2412 static void spi_controller_release(struct device *dev)
2413 {
2414 	struct spi_controller *ctlr;
2415 
2416 	ctlr = container_of(dev, struct spi_controller, dev);
2417 	kfree(ctlr);
2418 }
2419 
2420 static struct class spi_master_class = {
2421 	.name		= "spi_master",
2422 	.owner		= THIS_MODULE,
2423 	.dev_release	= spi_controller_release,
2424 	.dev_groups	= spi_master_groups,
2425 };
2426 
2427 #ifdef CONFIG_SPI_SLAVE
2428 /**
2429  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2430  *		     controller
2431  * @spi: device used for the current transfer
2432  */
2433 int spi_slave_abort(struct spi_device *spi)
2434 {
2435 	struct spi_controller *ctlr = spi->controller;
2436 
2437 	if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2438 		return ctlr->slave_abort(ctlr);
2439 
2440 	return -ENOTSUPP;
2441 }
2442 EXPORT_SYMBOL_GPL(spi_slave_abort);
2443 
2444 static int match_true(struct device *dev, void *data)
2445 {
2446 	return 1;
2447 }
2448 
2449 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2450 			  char *buf)
2451 {
2452 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2453 						   dev);
2454 	struct device *child;
2455 
2456 	child = device_find_child(&ctlr->dev, NULL, match_true);
2457 	return sprintf(buf, "%s\n",
2458 		       child ? to_spi_device(child)->modalias : NULL);
2459 }
2460 
2461 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2462 			   const char *buf, size_t count)
2463 {
2464 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2465 						   dev);
2466 	struct spi_device *spi;
2467 	struct device *child;
2468 	char name[32];
2469 	int rc;
2470 
2471 	rc = sscanf(buf, "%31s", name);
2472 	if (rc != 1 || !name[0])
2473 		return -EINVAL;
2474 
2475 	child = device_find_child(&ctlr->dev, NULL, match_true);
2476 	if (child) {
2477 		/* Remove registered slave */
2478 		device_unregister(child);
2479 		put_device(child);
2480 	}
2481 
2482 	if (strcmp(name, "(null)")) {
2483 		/* Register new slave */
2484 		spi = spi_alloc_device(ctlr);
2485 		if (!spi)
2486 			return -ENOMEM;
2487 
2488 		strlcpy(spi->modalias, name, sizeof(spi->modalias));
2489 
2490 		rc = spi_add_device(spi);
2491 		if (rc) {
2492 			spi_dev_put(spi);
2493 			return rc;
2494 		}
2495 	}
2496 
2497 	return count;
2498 }
2499 
2500 static DEVICE_ATTR_RW(slave);
2501 
2502 static struct attribute *spi_slave_attrs[] = {
2503 	&dev_attr_slave.attr,
2504 	NULL,
2505 };
2506 
2507 static const struct attribute_group spi_slave_group = {
2508 	.attrs = spi_slave_attrs,
2509 };
2510 
2511 static const struct attribute_group *spi_slave_groups[] = {
2512 	&spi_controller_statistics_group,
2513 	&spi_slave_group,
2514 	NULL,
2515 };
2516 
2517 static struct class spi_slave_class = {
2518 	.name		= "spi_slave",
2519 	.owner		= THIS_MODULE,
2520 	.dev_release	= spi_controller_release,
2521 	.dev_groups	= spi_slave_groups,
2522 };
2523 #else
2524 extern struct class spi_slave_class;	/* dummy */
2525 #endif
2526 
2527 /**
2528  * __spi_alloc_controller - allocate an SPI master or slave controller
2529  * @dev: the controller, possibly using the platform_bus
2530  * @size: how much zeroed driver-private data to allocate; the pointer to this
2531  *	memory is in the driver_data field of the returned device, accessible
2532  *	with spi_controller_get_devdata(); the memory is cacheline aligned;
2533  *	drivers granting DMA access to portions of their private data need to
2534  *	round up @size using ALIGN(size, dma_get_cache_alignment()).
2535  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2536  *	slave (true) controller
2537  * Context: can sleep
2538  *
2539  * This call is used only by SPI controller drivers, which are the
2540  * only ones directly touching chip registers.  It's how they allocate
2541  * an spi_controller structure, prior to calling spi_register_controller().
2542  *
2543  * This must be called from context that can sleep.
2544  *
2545  * The caller is responsible for assigning the bus number and initializing the
2546  * controller's methods before calling spi_register_controller(); and (after
2547  * errors adding the device) calling spi_controller_put() to prevent a memory
2548  * leak.
2549  *
2550  * Return: the SPI controller structure on success, else NULL.
2551  */
2552 struct spi_controller *__spi_alloc_controller(struct device *dev,
2553 					      unsigned int size, bool slave)
2554 {
2555 	struct spi_controller	*ctlr;
2556 	size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2557 
2558 	if (!dev)
2559 		return NULL;
2560 
2561 	ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2562 	if (!ctlr)
2563 		return NULL;
2564 
2565 	device_initialize(&ctlr->dev);
2566 	ctlr->bus_num = -1;
2567 	ctlr->num_chipselect = 1;
2568 	ctlr->slave = slave;
2569 	if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2570 		ctlr->dev.class = &spi_slave_class;
2571 	else
2572 		ctlr->dev.class = &spi_master_class;
2573 	ctlr->dev.parent = dev;
2574 	pm_suspend_ignore_children(&ctlr->dev, true);
2575 	spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2576 
2577 	return ctlr;
2578 }
2579 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2580 
2581 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2582 {
2583 	spi_controller_put(*(struct spi_controller **)ctlr);
2584 }
2585 
2586 /**
2587  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2588  * @dev: physical device of SPI controller
2589  * @size: how much zeroed driver-private data to allocate
2590  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2591  * Context: can sleep
2592  *
2593  * Allocate an SPI controller and automatically release a reference on it
2594  * when @dev is unbound from its driver.  Drivers are thus relieved from
2595  * having to call spi_controller_put().
2596  *
2597  * The arguments to this function are identical to __spi_alloc_controller().
2598  *
2599  * Return: the SPI controller structure on success, else NULL.
2600  */
2601 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2602 						   unsigned int size,
2603 						   bool slave)
2604 {
2605 	struct spi_controller **ptr, *ctlr;
2606 
2607 	ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2608 			   GFP_KERNEL);
2609 	if (!ptr)
2610 		return NULL;
2611 
2612 	ctlr = __spi_alloc_controller(dev, size, slave);
2613 	if (ctlr) {
2614 		ctlr->devm_allocated = true;
2615 		*ptr = ctlr;
2616 		devres_add(dev, ptr);
2617 	} else {
2618 		devres_free(ptr);
2619 	}
2620 
2621 	return ctlr;
2622 }
2623 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2624 
2625 #ifdef CONFIG_OF
2626 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2627 {
2628 	int nb, i, *cs;
2629 	struct device_node *np = ctlr->dev.of_node;
2630 
2631 	if (!np)
2632 		return 0;
2633 
2634 	nb = of_gpio_named_count(np, "cs-gpios");
2635 	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2636 
2637 	/* Return error only for an incorrectly formed cs-gpios property */
2638 	if (nb == 0 || nb == -ENOENT)
2639 		return 0;
2640 	else if (nb < 0)
2641 		return nb;
2642 
2643 	cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2644 			  GFP_KERNEL);
2645 	ctlr->cs_gpios = cs;
2646 
2647 	if (!ctlr->cs_gpios)
2648 		return -ENOMEM;
2649 
2650 	for (i = 0; i < ctlr->num_chipselect; i++)
2651 		cs[i] = -ENOENT;
2652 
2653 	for (i = 0; i < nb; i++)
2654 		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2655 
2656 	return 0;
2657 }
2658 #else
2659 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2660 {
2661 	return 0;
2662 }
2663 #endif
2664 
2665 /**
2666  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2667  * @ctlr: The SPI master to grab GPIO descriptors for
2668  */
2669 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2670 {
2671 	int nb, i;
2672 	struct gpio_desc **cs;
2673 	struct device *dev = &ctlr->dev;
2674 	unsigned long native_cs_mask = 0;
2675 	unsigned int num_cs_gpios = 0;
2676 
2677 	nb = gpiod_count(dev, "cs");
2678 	if (nb < 0) {
2679 		/* No GPIOs at all is fine, else return the error */
2680 		if (nb == -ENOENT)
2681 			return 0;
2682 		return nb;
2683 	}
2684 
2685 	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2686 
2687 	cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2688 			  GFP_KERNEL);
2689 	if (!cs)
2690 		return -ENOMEM;
2691 	ctlr->cs_gpiods = cs;
2692 
2693 	for (i = 0; i < nb; i++) {
2694 		/*
2695 		 * Most chipselects are active low, the inverted
2696 		 * semantics are handled by special quirks in gpiolib,
2697 		 * so initializing them GPIOD_OUT_LOW here means
2698 		 * "unasserted", in most cases this will drive the physical
2699 		 * line high.
2700 		 */
2701 		cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2702 						      GPIOD_OUT_LOW);
2703 		if (IS_ERR(cs[i]))
2704 			return PTR_ERR(cs[i]);
2705 
2706 		if (cs[i]) {
2707 			/*
2708 			 * If we find a CS GPIO, name it after the device and
2709 			 * chip select line.
2710 			 */
2711 			char *gpioname;
2712 
2713 			gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2714 						  dev_name(dev), i);
2715 			if (!gpioname)
2716 				return -ENOMEM;
2717 			gpiod_set_consumer_name(cs[i], gpioname);
2718 			num_cs_gpios++;
2719 			continue;
2720 		}
2721 
2722 		if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2723 			dev_err(dev, "Invalid native chip select %d\n", i);
2724 			return -EINVAL;
2725 		}
2726 		native_cs_mask |= BIT(i);
2727 	}
2728 
2729 	ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
2730 
2731 	if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
2732 	    ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
2733 		dev_err(dev, "No unused native chip select available\n");
2734 		return -EINVAL;
2735 	}
2736 
2737 	return 0;
2738 }
2739 
2740 static int spi_controller_check_ops(struct spi_controller *ctlr)
2741 {
2742 	/*
2743 	 * The controller may implement only the high-level SPI-memory like
2744 	 * operations if it does not support regular SPI transfers, and this is
2745 	 * valid use case.
2746 	 * If ->mem_ops is NULL, we request that at least one of the
2747 	 * ->transfer_xxx() method be implemented.
2748 	 */
2749 	if (ctlr->mem_ops) {
2750 		if (!ctlr->mem_ops->exec_op)
2751 			return -EINVAL;
2752 	} else if (!ctlr->transfer && !ctlr->transfer_one &&
2753 		   !ctlr->transfer_one_message) {
2754 		return -EINVAL;
2755 	}
2756 
2757 	return 0;
2758 }
2759 
2760 /**
2761  * spi_register_controller - register SPI master or slave controller
2762  * @ctlr: initialized master, originally from spi_alloc_master() or
2763  *	spi_alloc_slave()
2764  * Context: can sleep
2765  *
2766  * SPI controllers connect to their drivers using some non-SPI bus,
2767  * such as the platform bus.  The final stage of probe() in that code
2768  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2769  *
2770  * SPI controllers use board specific (often SOC specific) bus numbers,
2771  * and board-specific addressing for SPI devices combines those numbers
2772  * with chip select numbers.  Since SPI does not directly support dynamic
2773  * device identification, boards need configuration tables telling which
2774  * chip is at which address.
2775  *
2776  * This must be called from context that can sleep.  It returns zero on
2777  * success, else a negative error code (dropping the controller's refcount).
2778  * After a successful return, the caller is responsible for calling
2779  * spi_unregister_controller().
2780  *
2781  * Return: zero on success, else a negative error code.
2782  */
2783 int spi_register_controller(struct spi_controller *ctlr)
2784 {
2785 	struct device		*dev = ctlr->dev.parent;
2786 	struct boardinfo	*bi;
2787 	int			status;
2788 	int			id, first_dynamic;
2789 
2790 	if (!dev)
2791 		return -ENODEV;
2792 
2793 	/*
2794 	 * Make sure all necessary hooks are implemented before registering
2795 	 * the SPI controller.
2796 	 */
2797 	status = spi_controller_check_ops(ctlr);
2798 	if (status)
2799 		return status;
2800 
2801 	if (ctlr->bus_num >= 0) {
2802 		/* devices with a fixed bus num must check-in with the num */
2803 		mutex_lock(&board_lock);
2804 		id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2805 			ctlr->bus_num + 1, GFP_KERNEL);
2806 		mutex_unlock(&board_lock);
2807 		if (WARN(id < 0, "couldn't get idr"))
2808 			return id == -ENOSPC ? -EBUSY : id;
2809 		ctlr->bus_num = id;
2810 	} else if (ctlr->dev.of_node) {
2811 		/* allocate dynamic bus number using Linux idr */
2812 		id = of_alias_get_id(ctlr->dev.of_node, "spi");
2813 		if (id >= 0) {
2814 			ctlr->bus_num = id;
2815 			mutex_lock(&board_lock);
2816 			id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2817 				       ctlr->bus_num + 1, GFP_KERNEL);
2818 			mutex_unlock(&board_lock);
2819 			if (WARN(id < 0, "couldn't get idr"))
2820 				return id == -ENOSPC ? -EBUSY : id;
2821 		}
2822 	}
2823 	if (ctlr->bus_num < 0) {
2824 		first_dynamic = of_alias_get_highest_id("spi");
2825 		if (first_dynamic < 0)
2826 			first_dynamic = 0;
2827 		else
2828 			first_dynamic++;
2829 
2830 		mutex_lock(&board_lock);
2831 		id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2832 			       0, GFP_KERNEL);
2833 		mutex_unlock(&board_lock);
2834 		if (WARN(id < 0, "couldn't get idr"))
2835 			return id;
2836 		ctlr->bus_num = id;
2837 	}
2838 	INIT_LIST_HEAD(&ctlr->queue);
2839 	spin_lock_init(&ctlr->queue_lock);
2840 	spin_lock_init(&ctlr->bus_lock_spinlock);
2841 	mutex_init(&ctlr->bus_lock_mutex);
2842 	mutex_init(&ctlr->io_mutex);
2843 	ctlr->bus_lock_flag = 0;
2844 	init_completion(&ctlr->xfer_completion);
2845 	if (!ctlr->max_dma_len)
2846 		ctlr->max_dma_len = INT_MAX;
2847 
2848 	/* register the device, then userspace will see it.
2849 	 * registration fails if the bus ID is in use.
2850 	 */
2851 	dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2852 
2853 	if (!spi_controller_is_slave(ctlr)) {
2854 		if (ctlr->use_gpio_descriptors) {
2855 			status = spi_get_gpio_descs(ctlr);
2856 			if (status)
2857 				goto free_bus_id;
2858 			/*
2859 			 * A controller using GPIO descriptors always
2860 			 * supports SPI_CS_HIGH if need be.
2861 			 */
2862 			ctlr->mode_bits |= SPI_CS_HIGH;
2863 		} else {
2864 			/* Legacy code path for GPIOs from DT */
2865 			status = of_spi_get_gpio_numbers(ctlr);
2866 			if (status)
2867 				goto free_bus_id;
2868 		}
2869 	}
2870 
2871 	/*
2872 	 * Even if it's just one always-selected device, there must
2873 	 * be at least one chipselect.
2874 	 */
2875 	if (!ctlr->num_chipselect) {
2876 		status = -EINVAL;
2877 		goto free_bus_id;
2878 	}
2879 
2880 	status = device_add(&ctlr->dev);
2881 	if (status < 0)
2882 		goto free_bus_id;
2883 	dev_dbg(dev, "registered %s %s\n",
2884 			spi_controller_is_slave(ctlr) ? "slave" : "master",
2885 			dev_name(&ctlr->dev));
2886 
2887 	/*
2888 	 * If we're using a queued driver, start the queue. Note that we don't
2889 	 * need the queueing logic if the driver is only supporting high-level
2890 	 * memory operations.
2891 	 */
2892 	if (ctlr->transfer) {
2893 		dev_info(dev, "controller is unqueued, this is deprecated\n");
2894 	} else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2895 		status = spi_controller_initialize_queue(ctlr);
2896 		if (status) {
2897 			device_del(&ctlr->dev);
2898 			goto free_bus_id;
2899 		}
2900 	}
2901 	/* add statistics */
2902 	spin_lock_init(&ctlr->statistics.lock);
2903 
2904 	mutex_lock(&board_lock);
2905 	list_add_tail(&ctlr->list, &spi_controller_list);
2906 	list_for_each_entry(bi, &board_list, list)
2907 		spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2908 	mutex_unlock(&board_lock);
2909 
2910 	/* Register devices from the device tree and ACPI */
2911 	of_register_spi_devices(ctlr);
2912 	acpi_register_spi_devices(ctlr);
2913 	return status;
2914 
2915 free_bus_id:
2916 	mutex_lock(&board_lock);
2917 	idr_remove(&spi_master_idr, ctlr->bus_num);
2918 	mutex_unlock(&board_lock);
2919 	return status;
2920 }
2921 EXPORT_SYMBOL_GPL(spi_register_controller);
2922 
2923 static void devm_spi_unregister(void *ctlr)
2924 {
2925 	spi_unregister_controller(ctlr);
2926 }
2927 
2928 /**
2929  * devm_spi_register_controller - register managed SPI master or slave
2930  *	controller
2931  * @dev:    device managing SPI controller
2932  * @ctlr: initialized controller, originally from spi_alloc_master() or
2933  *	spi_alloc_slave()
2934  * Context: can sleep
2935  *
2936  * Register a SPI device as with spi_register_controller() which will
2937  * automatically be unregistered and freed.
2938  *
2939  * Return: zero on success, else a negative error code.
2940  */
2941 int devm_spi_register_controller(struct device *dev,
2942 				 struct spi_controller *ctlr)
2943 {
2944 	int ret;
2945 
2946 	ret = spi_register_controller(ctlr);
2947 	if (ret)
2948 		return ret;
2949 
2950 	return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
2951 }
2952 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2953 
2954 static int __unregister(struct device *dev, void *null)
2955 {
2956 	spi_unregister_device(to_spi_device(dev));
2957 	return 0;
2958 }
2959 
2960 /**
2961  * spi_unregister_controller - unregister SPI master or slave controller
2962  * @ctlr: the controller being unregistered
2963  * Context: can sleep
2964  *
2965  * This call is used only by SPI controller drivers, which are the
2966  * only ones directly touching chip registers.
2967  *
2968  * This must be called from context that can sleep.
2969  *
2970  * Note that this function also drops a reference to the controller.
2971  */
2972 void spi_unregister_controller(struct spi_controller *ctlr)
2973 {
2974 	struct spi_controller *found;
2975 	int id = ctlr->bus_num;
2976 
2977 	/* Prevent addition of new devices, unregister existing ones */
2978 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2979 		mutex_lock(&spi_add_lock);
2980 
2981 	device_for_each_child(&ctlr->dev, NULL, __unregister);
2982 
2983 	/* First make sure that this controller was ever added */
2984 	mutex_lock(&board_lock);
2985 	found = idr_find(&spi_master_idr, id);
2986 	mutex_unlock(&board_lock);
2987 	if (ctlr->queued) {
2988 		if (spi_destroy_queue(ctlr))
2989 			dev_err(&ctlr->dev, "queue remove failed\n");
2990 	}
2991 	mutex_lock(&board_lock);
2992 	list_del(&ctlr->list);
2993 	mutex_unlock(&board_lock);
2994 
2995 	device_del(&ctlr->dev);
2996 
2997 	/* Release the last reference on the controller if its driver
2998 	 * has not yet been converted to devm_spi_alloc_master/slave().
2999 	 */
3000 	if (!ctlr->devm_allocated)
3001 		put_device(&ctlr->dev);
3002 
3003 	/* free bus id */
3004 	mutex_lock(&board_lock);
3005 	if (found == ctlr)
3006 		idr_remove(&spi_master_idr, id);
3007 	mutex_unlock(&board_lock);
3008 
3009 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3010 		mutex_unlock(&spi_add_lock);
3011 }
3012 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3013 
3014 int spi_controller_suspend(struct spi_controller *ctlr)
3015 {
3016 	int ret;
3017 
3018 	/* Basically no-ops for non-queued controllers */
3019 	if (!ctlr->queued)
3020 		return 0;
3021 
3022 	ret = spi_stop_queue(ctlr);
3023 	if (ret)
3024 		dev_err(&ctlr->dev, "queue stop failed\n");
3025 
3026 	return ret;
3027 }
3028 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3029 
3030 int spi_controller_resume(struct spi_controller *ctlr)
3031 {
3032 	int ret;
3033 
3034 	if (!ctlr->queued)
3035 		return 0;
3036 
3037 	ret = spi_start_queue(ctlr);
3038 	if (ret)
3039 		dev_err(&ctlr->dev, "queue restart failed\n");
3040 
3041 	return ret;
3042 }
3043 EXPORT_SYMBOL_GPL(spi_controller_resume);
3044 
3045 static int __spi_controller_match(struct device *dev, const void *data)
3046 {
3047 	struct spi_controller *ctlr;
3048 	const u16 *bus_num = data;
3049 
3050 	ctlr = container_of(dev, struct spi_controller, dev);
3051 	return ctlr->bus_num == *bus_num;
3052 }
3053 
3054 /**
3055  * spi_busnum_to_master - look up master associated with bus_num
3056  * @bus_num: the master's bus number
3057  * Context: can sleep
3058  *
3059  * This call may be used with devices that are registered after
3060  * arch init time.  It returns a refcounted pointer to the relevant
3061  * spi_controller (which the caller must release), or NULL if there is
3062  * no such master registered.
3063  *
3064  * Return: the SPI master structure on success, else NULL.
3065  */
3066 struct spi_controller *spi_busnum_to_master(u16 bus_num)
3067 {
3068 	struct device		*dev;
3069 	struct spi_controller	*ctlr = NULL;
3070 
3071 	dev = class_find_device(&spi_master_class, NULL, &bus_num,
3072 				__spi_controller_match);
3073 	if (dev)
3074 		ctlr = container_of(dev, struct spi_controller, dev);
3075 	/* reference got in class_find_device */
3076 	return ctlr;
3077 }
3078 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
3079 
3080 /*-------------------------------------------------------------------------*/
3081 
3082 /* Core methods for SPI resource management */
3083 
3084 /**
3085  * spi_res_alloc - allocate a spi resource that is life-cycle managed
3086  *                 during the processing of a spi_message while using
3087  *                 spi_transfer_one
3088  * @spi:     the spi device for which we allocate memory
3089  * @release: the release code to execute for this resource
3090  * @size:    size to alloc and return
3091  * @gfp:     GFP allocation flags
3092  *
3093  * Return: the pointer to the allocated data
3094  *
3095  * This may get enhanced in the future to allocate from a memory pool
3096  * of the @spi_device or @spi_controller to avoid repeated allocations.
3097  */
3098 void *spi_res_alloc(struct spi_device *spi,
3099 		    spi_res_release_t release,
3100 		    size_t size, gfp_t gfp)
3101 {
3102 	struct spi_res *sres;
3103 
3104 	sres = kzalloc(sizeof(*sres) + size, gfp);
3105 	if (!sres)
3106 		return NULL;
3107 
3108 	INIT_LIST_HEAD(&sres->entry);
3109 	sres->release = release;
3110 
3111 	return sres->data;
3112 }
3113 EXPORT_SYMBOL_GPL(spi_res_alloc);
3114 
3115 /**
3116  * spi_res_free - free an spi resource
3117  * @res: pointer to the custom data of a resource
3118  *
3119  */
3120 void spi_res_free(void *res)
3121 {
3122 	struct spi_res *sres = container_of(res, struct spi_res, data);
3123 
3124 	if (!res)
3125 		return;
3126 
3127 	WARN_ON(!list_empty(&sres->entry));
3128 	kfree(sres);
3129 }
3130 EXPORT_SYMBOL_GPL(spi_res_free);
3131 
3132 /**
3133  * spi_res_add - add a spi_res to the spi_message
3134  * @message: the spi message
3135  * @res:     the spi_resource
3136  */
3137 void spi_res_add(struct spi_message *message, void *res)
3138 {
3139 	struct spi_res *sres = container_of(res, struct spi_res, data);
3140 
3141 	WARN_ON(!list_empty(&sres->entry));
3142 	list_add_tail(&sres->entry, &message->resources);
3143 }
3144 EXPORT_SYMBOL_GPL(spi_res_add);
3145 
3146 /**
3147  * spi_res_release - release all spi resources for this message
3148  * @ctlr:  the @spi_controller
3149  * @message: the @spi_message
3150  */
3151 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
3152 {
3153 	struct spi_res *res, *tmp;
3154 
3155 	list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
3156 		if (res->release)
3157 			res->release(ctlr, message, res->data);
3158 
3159 		list_del(&res->entry);
3160 
3161 		kfree(res);
3162 	}
3163 }
3164 EXPORT_SYMBOL_GPL(spi_res_release);
3165 
3166 /*-------------------------------------------------------------------------*/
3167 
3168 /* Core methods for spi_message alterations */
3169 
3170 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3171 					    struct spi_message *msg,
3172 					    void *res)
3173 {
3174 	struct spi_replaced_transfers *rxfer = res;
3175 	size_t i;
3176 
3177 	/* call extra callback if requested */
3178 	if (rxfer->release)
3179 		rxfer->release(ctlr, msg, res);
3180 
3181 	/* insert replaced transfers back into the message */
3182 	list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3183 
3184 	/* remove the formerly inserted entries */
3185 	for (i = 0; i < rxfer->inserted; i++)
3186 		list_del(&rxfer->inserted_transfers[i].transfer_list);
3187 }
3188 
3189 /**
3190  * spi_replace_transfers - replace transfers with several transfers
3191  *                         and register change with spi_message.resources
3192  * @msg:           the spi_message we work upon
3193  * @xfer_first:    the first spi_transfer we want to replace
3194  * @remove:        number of transfers to remove
3195  * @insert:        the number of transfers we want to insert instead
3196  * @release:       extra release code necessary in some circumstances
3197  * @extradatasize: extra data to allocate (with alignment guarantees
3198  *                 of struct @spi_transfer)
3199  * @gfp:           gfp flags
3200  *
3201  * Returns: pointer to @spi_replaced_transfers,
3202  *          PTR_ERR(...) in case of errors.
3203  */
3204 struct spi_replaced_transfers *spi_replace_transfers(
3205 	struct spi_message *msg,
3206 	struct spi_transfer *xfer_first,
3207 	size_t remove,
3208 	size_t insert,
3209 	spi_replaced_release_t release,
3210 	size_t extradatasize,
3211 	gfp_t gfp)
3212 {
3213 	struct spi_replaced_transfers *rxfer;
3214 	struct spi_transfer *xfer;
3215 	size_t i;
3216 
3217 	/* allocate the structure using spi_res */
3218 	rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3219 			      struct_size(rxfer, inserted_transfers, insert)
3220 			      + extradatasize,
3221 			      gfp);
3222 	if (!rxfer)
3223 		return ERR_PTR(-ENOMEM);
3224 
3225 	/* the release code to invoke before running the generic release */
3226 	rxfer->release = release;
3227 
3228 	/* assign extradata */
3229 	if (extradatasize)
3230 		rxfer->extradata =
3231 			&rxfer->inserted_transfers[insert];
3232 
3233 	/* init the replaced_transfers list */
3234 	INIT_LIST_HEAD(&rxfer->replaced_transfers);
3235 
3236 	/* assign the list_entry after which we should reinsert
3237 	 * the @replaced_transfers - it may be spi_message.messages!
3238 	 */
3239 	rxfer->replaced_after = xfer_first->transfer_list.prev;
3240 
3241 	/* remove the requested number of transfers */
3242 	for (i = 0; i < remove; i++) {
3243 		/* if the entry after replaced_after it is msg->transfers
3244 		 * then we have been requested to remove more transfers
3245 		 * than are in the list
3246 		 */
3247 		if (rxfer->replaced_after->next == &msg->transfers) {
3248 			dev_err(&msg->spi->dev,
3249 				"requested to remove more spi_transfers than are available\n");
3250 			/* insert replaced transfers back into the message */
3251 			list_splice(&rxfer->replaced_transfers,
3252 				    rxfer->replaced_after);
3253 
3254 			/* free the spi_replace_transfer structure */
3255 			spi_res_free(rxfer);
3256 
3257 			/* and return with an error */
3258 			return ERR_PTR(-EINVAL);
3259 		}
3260 
3261 		/* remove the entry after replaced_after from list of
3262 		 * transfers and add it to list of replaced_transfers
3263 		 */
3264 		list_move_tail(rxfer->replaced_after->next,
3265 			       &rxfer->replaced_transfers);
3266 	}
3267 
3268 	/* create copy of the given xfer with identical settings
3269 	 * based on the first transfer to get removed
3270 	 */
3271 	for (i = 0; i < insert; i++) {
3272 		/* we need to run in reverse order */
3273 		xfer = &rxfer->inserted_transfers[insert - 1 - i];
3274 
3275 		/* copy all spi_transfer data */
3276 		memcpy(xfer, xfer_first, sizeof(*xfer));
3277 
3278 		/* add to list */
3279 		list_add(&xfer->transfer_list, rxfer->replaced_after);
3280 
3281 		/* clear cs_change and delay for all but the last */
3282 		if (i) {
3283 			xfer->cs_change = false;
3284 			xfer->delay.value = 0;
3285 		}
3286 	}
3287 
3288 	/* set up inserted */
3289 	rxfer->inserted = insert;
3290 
3291 	/* and register it with spi_res/spi_message */
3292 	spi_res_add(msg, rxfer);
3293 
3294 	return rxfer;
3295 }
3296 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3297 
3298 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3299 					struct spi_message *msg,
3300 					struct spi_transfer **xferp,
3301 					size_t maxsize,
3302 					gfp_t gfp)
3303 {
3304 	struct spi_transfer *xfer = *xferp, *xfers;
3305 	struct spi_replaced_transfers *srt;
3306 	size_t offset;
3307 	size_t count, i;
3308 
3309 	/* calculate how many we have to replace */
3310 	count = DIV_ROUND_UP(xfer->len, maxsize);
3311 
3312 	/* create replacement */
3313 	srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3314 	if (IS_ERR(srt))
3315 		return PTR_ERR(srt);
3316 	xfers = srt->inserted_transfers;
3317 
3318 	/* now handle each of those newly inserted spi_transfers
3319 	 * note that the replacements spi_transfers all are preset
3320 	 * to the same values as *xferp, so tx_buf, rx_buf and len
3321 	 * are all identical (as well as most others)
3322 	 * so we just have to fix up len and the pointers.
3323 	 *
3324 	 * this also includes support for the depreciated
3325 	 * spi_message.is_dma_mapped interface
3326 	 */
3327 
3328 	/* the first transfer just needs the length modified, so we
3329 	 * run it outside the loop
3330 	 */
3331 	xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3332 
3333 	/* all the others need rx_buf/tx_buf also set */
3334 	for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3335 		/* update rx_buf, tx_buf and dma */
3336 		if (xfers[i].rx_buf)
3337 			xfers[i].rx_buf += offset;
3338 		if (xfers[i].rx_dma)
3339 			xfers[i].rx_dma += offset;
3340 		if (xfers[i].tx_buf)
3341 			xfers[i].tx_buf += offset;
3342 		if (xfers[i].tx_dma)
3343 			xfers[i].tx_dma += offset;
3344 
3345 		/* update length */
3346 		xfers[i].len = min(maxsize, xfers[i].len - offset);
3347 	}
3348 
3349 	/* we set up xferp to the last entry we have inserted,
3350 	 * so that we skip those already split transfers
3351 	 */
3352 	*xferp = &xfers[count - 1];
3353 
3354 	/* increment statistics counters */
3355 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3356 				       transfers_split_maxsize);
3357 	SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3358 				       transfers_split_maxsize);
3359 
3360 	return 0;
3361 }
3362 
3363 /**
3364  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3365  *                               when an individual transfer exceeds a
3366  *                               certain size
3367  * @ctlr:    the @spi_controller for this transfer
3368  * @msg:   the @spi_message to transform
3369  * @maxsize:  the maximum when to apply this
3370  * @gfp: GFP allocation flags
3371  *
3372  * Return: status of transformation
3373  */
3374 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3375 				struct spi_message *msg,
3376 				size_t maxsize,
3377 				gfp_t gfp)
3378 {
3379 	struct spi_transfer *xfer;
3380 	int ret;
3381 
3382 	/* iterate over the transfer_list,
3383 	 * but note that xfer is advanced to the last transfer inserted
3384 	 * to avoid checking sizes again unnecessarily (also xfer does
3385 	 * potentiall belong to a different list by the time the
3386 	 * replacement has happened
3387 	 */
3388 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3389 		if (xfer->len > maxsize) {
3390 			ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3391 							   maxsize, gfp);
3392 			if (ret)
3393 				return ret;
3394 		}
3395 	}
3396 
3397 	return 0;
3398 }
3399 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3400 
3401 /*-------------------------------------------------------------------------*/
3402 
3403 /* Core methods for SPI controller protocol drivers.  Some of the
3404  * other core methods are currently defined as inline functions.
3405  */
3406 
3407 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3408 					u8 bits_per_word)
3409 {
3410 	if (ctlr->bits_per_word_mask) {
3411 		/* Only 32 bits fit in the mask */
3412 		if (bits_per_word > 32)
3413 			return -EINVAL;
3414 		if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3415 			return -EINVAL;
3416 	}
3417 
3418 	return 0;
3419 }
3420 
3421 /**
3422  * spi_setup - setup SPI mode and clock rate
3423  * @spi: the device whose settings are being modified
3424  * Context: can sleep, and no requests are queued to the device
3425  *
3426  * SPI protocol drivers may need to update the transfer mode if the
3427  * device doesn't work with its default.  They may likewise need
3428  * to update clock rates or word sizes from initial values.  This function
3429  * changes those settings, and must be called from a context that can sleep.
3430  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3431  * effect the next time the device is selected and data is transferred to
3432  * or from it.  When this function returns, the spi device is deselected.
3433  *
3434  * Note that this call will fail if the protocol driver specifies an option
3435  * that the underlying controller or its driver does not support.  For
3436  * example, not all hardware supports wire transfers using nine bit words,
3437  * LSB-first wire encoding, or active-high chipselects.
3438  *
3439  * Return: zero on success, else a negative error code.
3440  */
3441 int spi_setup(struct spi_device *spi)
3442 {
3443 	unsigned	bad_bits, ugly_bits;
3444 	int		status;
3445 
3446 	/*
3447 	 * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3448 	 * are set at the same time
3449 	 */
3450 	if ((hweight_long(spi->mode &
3451 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3452 	    (hweight_long(spi->mode &
3453 		(SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3454 		dev_err(&spi->dev,
3455 		"setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3456 		return -EINVAL;
3457 	}
3458 	/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3459 	 */
3460 	if ((spi->mode & SPI_3WIRE) && (spi->mode &
3461 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3462 		 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3463 		return -EINVAL;
3464 	/* help drivers fail *cleanly* when they need options
3465 	 * that aren't supported with their current controller
3466 	 * SPI_CS_WORD has a fallback software implementation,
3467 	 * so it is ignored here.
3468 	 */
3469 	bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3470 				 SPI_NO_TX | SPI_NO_RX);
3471 	/* nothing prevents from working with active-high CS in case if it
3472 	 * is driven by GPIO.
3473 	 */
3474 	if (gpio_is_valid(spi->cs_gpio))
3475 		bad_bits &= ~SPI_CS_HIGH;
3476 	ugly_bits = bad_bits &
3477 		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3478 		     SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3479 	if (ugly_bits) {
3480 		dev_warn(&spi->dev,
3481 			 "setup: ignoring unsupported mode bits %x\n",
3482 			 ugly_bits);
3483 		spi->mode &= ~ugly_bits;
3484 		bad_bits &= ~ugly_bits;
3485 	}
3486 	if (bad_bits) {
3487 		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3488 			bad_bits);
3489 		return -EINVAL;
3490 	}
3491 
3492 	if (!spi->bits_per_word)
3493 		spi->bits_per_word = 8;
3494 
3495 	status = __spi_validate_bits_per_word(spi->controller,
3496 					      spi->bits_per_word);
3497 	if (status)
3498 		return status;
3499 
3500 	if (spi->controller->max_speed_hz &&
3501 	    (!spi->max_speed_hz ||
3502 	     spi->max_speed_hz > spi->controller->max_speed_hz))
3503 		spi->max_speed_hz = spi->controller->max_speed_hz;
3504 
3505 	mutex_lock(&spi->controller->io_mutex);
3506 
3507 	if (spi->controller->setup) {
3508 		status = spi->controller->setup(spi);
3509 		if (status) {
3510 			mutex_unlock(&spi->controller->io_mutex);
3511 			dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3512 				status);
3513 			return status;
3514 		}
3515 	}
3516 
3517 	if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3518 		status = pm_runtime_get_sync(spi->controller->dev.parent);
3519 		if (status < 0) {
3520 			mutex_unlock(&spi->controller->io_mutex);
3521 			pm_runtime_put_noidle(spi->controller->dev.parent);
3522 			dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3523 				status);
3524 			return status;
3525 		}
3526 
3527 		/*
3528 		 * We do not want to return positive value from pm_runtime_get,
3529 		 * there are many instances of devices calling spi_setup() and
3530 		 * checking for a non-zero return value instead of a negative
3531 		 * return value.
3532 		 */
3533 		status = 0;
3534 
3535 		spi_set_cs(spi, false, true);
3536 		pm_runtime_mark_last_busy(spi->controller->dev.parent);
3537 		pm_runtime_put_autosuspend(spi->controller->dev.parent);
3538 	} else {
3539 		spi_set_cs(spi, false, true);
3540 	}
3541 
3542 	mutex_unlock(&spi->controller->io_mutex);
3543 
3544 	if (spi->rt && !spi->controller->rt) {
3545 		spi->controller->rt = true;
3546 		spi_set_thread_rt(spi->controller);
3547 	}
3548 
3549 	trace_spi_setup(spi, status);
3550 
3551 	dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3552 			spi->mode & SPI_MODE_X_MASK,
3553 			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3554 			(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3555 			(spi->mode & SPI_3WIRE) ? "3wire, " : "",
3556 			(spi->mode & SPI_LOOP) ? "loopback, " : "",
3557 			spi->bits_per_word, spi->max_speed_hz,
3558 			status);
3559 
3560 	return status;
3561 }
3562 EXPORT_SYMBOL_GPL(spi_setup);
3563 
3564 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3565 				       struct spi_device *spi)
3566 {
3567 	int delay1, delay2;
3568 
3569 	delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3570 	if (delay1 < 0)
3571 		return delay1;
3572 
3573 	delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3574 	if (delay2 < 0)
3575 		return delay2;
3576 
3577 	if (delay1 < delay2)
3578 		memcpy(&xfer->word_delay, &spi->word_delay,
3579 		       sizeof(xfer->word_delay));
3580 
3581 	return 0;
3582 }
3583 
3584 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3585 {
3586 	struct spi_controller *ctlr = spi->controller;
3587 	struct spi_transfer *xfer;
3588 	int w_size;
3589 
3590 	if (list_empty(&message->transfers))
3591 		return -EINVAL;
3592 
3593 	/* If an SPI controller does not support toggling the CS line on each
3594 	 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3595 	 * for the CS line, we can emulate the CS-per-word hardware function by
3596 	 * splitting transfers into one-word transfers and ensuring that
3597 	 * cs_change is set for each transfer.
3598 	 */
3599 	if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3600 					  spi->cs_gpiod ||
3601 					  gpio_is_valid(spi->cs_gpio))) {
3602 		size_t maxsize;
3603 		int ret;
3604 
3605 		maxsize = (spi->bits_per_word + 7) / 8;
3606 
3607 		/* spi_split_transfers_maxsize() requires message->spi */
3608 		message->spi = spi;
3609 
3610 		ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3611 						  GFP_KERNEL);
3612 		if (ret)
3613 			return ret;
3614 
3615 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3616 			/* don't change cs_change on the last entry in the list */
3617 			if (list_is_last(&xfer->transfer_list, &message->transfers))
3618 				break;
3619 			xfer->cs_change = 1;
3620 		}
3621 	}
3622 
3623 	/* Half-duplex links include original MicroWire, and ones with
3624 	 * only one data pin like SPI_3WIRE (switches direction) or where
3625 	 * either MOSI or MISO is missing.  They can also be caused by
3626 	 * software limitations.
3627 	 */
3628 	if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3629 	    (spi->mode & SPI_3WIRE)) {
3630 		unsigned flags = ctlr->flags;
3631 
3632 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3633 			if (xfer->rx_buf && xfer->tx_buf)
3634 				return -EINVAL;
3635 			if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3636 				return -EINVAL;
3637 			if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3638 				return -EINVAL;
3639 		}
3640 	}
3641 
3642 	/**
3643 	 * Set transfer bits_per_word and max speed as spi device default if
3644 	 * it is not set for this transfer.
3645 	 * Set transfer tx_nbits and rx_nbits as single transfer default
3646 	 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3647 	 * Ensure transfer word_delay is at least as long as that required by
3648 	 * device itself.
3649 	 */
3650 	message->frame_length = 0;
3651 	list_for_each_entry(xfer, &message->transfers, transfer_list) {
3652 		xfer->effective_speed_hz = 0;
3653 		message->frame_length += xfer->len;
3654 		if (!xfer->bits_per_word)
3655 			xfer->bits_per_word = spi->bits_per_word;
3656 
3657 		if (!xfer->speed_hz)
3658 			xfer->speed_hz = spi->max_speed_hz;
3659 
3660 		if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3661 			xfer->speed_hz = ctlr->max_speed_hz;
3662 
3663 		if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3664 			return -EINVAL;
3665 
3666 		/*
3667 		 * SPI transfer length should be multiple of SPI word size
3668 		 * where SPI word size should be power-of-two multiple
3669 		 */
3670 		if (xfer->bits_per_word <= 8)
3671 			w_size = 1;
3672 		else if (xfer->bits_per_word <= 16)
3673 			w_size = 2;
3674 		else
3675 			w_size = 4;
3676 
3677 		/* No partial transfers accepted */
3678 		if (xfer->len % w_size)
3679 			return -EINVAL;
3680 
3681 		if (xfer->speed_hz && ctlr->min_speed_hz &&
3682 		    xfer->speed_hz < ctlr->min_speed_hz)
3683 			return -EINVAL;
3684 
3685 		if (xfer->tx_buf && !xfer->tx_nbits)
3686 			xfer->tx_nbits = SPI_NBITS_SINGLE;
3687 		if (xfer->rx_buf && !xfer->rx_nbits)
3688 			xfer->rx_nbits = SPI_NBITS_SINGLE;
3689 		/* check transfer tx/rx_nbits:
3690 		 * 1. check the value matches one of single, dual and quad
3691 		 * 2. check tx/rx_nbits match the mode in spi_device
3692 		 */
3693 		if (xfer->tx_buf) {
3694 			if (spi->mode & SPI_NO_TX)
3695 				return -EINVAL;
3696 			if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3697 				xfer->tx_nbits != SPI_NBITS_DUAL &&
3698 				xfer->tx_nbits != SPI_NBITS_QUAD)
3699 				return -EINVAL;
3700 			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3701 				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3702 				return -EINVAL;
3703 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3704 				!(spi->mode & SPI_TX_QUAD))
3705 				return -EINVAL;
3706 		}
3707 		/* check transfer rx_nbits */
3708 		if (xfer->rx_buf) {
3709 			if (spi->mode & SPI_NO_RX)
3710 				return -EINVAL;
3711 			if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3712 				xfer->rx_nbits != SPI_NBITS_DUAL &&
3713 				xfer->rx_nbits != SPI_NBITS_QUAD)
3714 				return -EINVAL;
3715 			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3716 				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3717 				return -EINVAL;
3718 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3719 				!(spi->mode & SPI_RX_QUAD))
3720 				return -EINVAL;
3721 		}
3722 
3723 		if (_spi_xfer_word_delay_update(xfer, spi))
3724 			return -EINVAL;
3725 	}
3726 
3727 	message->status = -EINPROGRESS;
3728 
3729 	return 0;
3730 }
3731 
3732 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3733 {
3734 	struct spi_controller *ctlr = spi->controller;
3735 	struct spi_transfer *xfer;
3736 
3737 	/*
3738 	 * Some controllers do not support doing regular SPI transfers. Return
3739 	 * ENOTSUPP when this is the case.
3740 	 */
3741 	if (!ctlr->transfer)
3742 		return -ENOTSUPP;
3743 
3744 	message->spi = spi;
3745 
3746 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3747 	SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3748 
3749 	trace_spi_message_submit(message);
3750 
3751 	if (!ctlr->ptp_sts_supported) {
3752 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3753 			xfer->ptp_sts_word_pre = 0;
3754 			ptp_read_system_prets(xfer->ptp_sts);
3755 		}
3756 	}
3757 
3758 	return ctlr->transfer(spi, message);
3759 }
3760 
3761 /**
3762  * spi_async - asynchronous SPI transfer
3763  * @spi: device with which data will be exchanged
3764  * @message: describes the data transfers, including completion callback
3765  * Context: any (irqs may be blocked, etc)
3766  *
3767  * This call may be used in_irq and other contexts which can't sleep,
3768  * as well as from task contexts which can sleep.
3769  *
3770  * The completion callback is invoked in a context which can't sleep.
3771  * Before that invocation, the value of message->status is undefined.
3772  * When the callback is issued, message->status holds either zero (to
3773  * indicate complete success) or a negative error code.  After that
3774  * callback returns, the driver which issued the transfer request may
3775  * deallocate the associated memory; it's no longer in use by any SPI
3776  * core or controller driver code.
3777  *
3778  * Note that although all messages to a spi_device are handled in
3779  * FIFO order, messages may go to different devices in other orders.
3780  * Some device might be higher priority, or have various "hard" access
3781  * time requirements, for example.
3782  *
3783  * On detection of any fault during the transfer, processing of
3784  * the entire message is aborted, and the device is deselected.
3785  * Until returning from the associated message completion callback,
3786  * no other spi_message queued to that device will be processed.
3787  * (This rule applies equally to all the synchronous transfer calls,
3788  * which are wrappers around this core asynchronous primitive.)
3789  *
3790  * Return: zero on success, else a negative error code.
3791  */
3792 int spi_async(struct spi_device *spi, struct spi_message *message)
3793 {
3794 	struct spi_controller *ctlr = spi->controller;
3795 	int ret;
3796 	unsigned long flags;
3797 
3798 	ret = __spi_validate(spi, message);
3799 	if (ret != 0)
3800 		return ret;
3801 
3802 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3803 
3804 	if (ctlr->bus_lock_flag)
3805 		ret = -EBUSY;
3806 	else
3807 		ret = __spi_async(spi, message);
3808 
3809 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3810 
3811 	return ret;
3812 }
3813 EXPORT_SYMBOL_GPL(spi_async);
3814 
3815 /**
3816  * spi_async_locked - version of spi_async with exclusive bus usage
3817  * @spi: device with which data will be exchanged
3818  * @message: describes the data transfers, including completion callback
3819  * Context: any (irqs may be blocked, etc)
3820  *
3821  * This call may be used in_irq and other contexts which can't sleep,
3822  * as well as from task contexts which can sleep.
3823  *
3824  * The completion callback is invoked in a context which can't sleep.
3825  * Before that invocation, the value of message->status is undefined.
3826  * When the callback is issued, message->status holds either zero (to
3827  * indicate complete success) or a negative error code.  After that
3828  * callback returns, the driver which issued the transfer request may
3829  * deallocate the associated memory; it's no longer in use by any SPI
3830  * core or controller driver code.
3831  *
3832  * Note that although all messages to a spi_device are handled in
3833  * FIFO order, messages may go to different devices in other orders.
3834  * Some device might be higher priority, or have various "hard" access
3835  * time requirements, for example.
3836  *
3837  * On detection of any fault during the transfer, processing of
3838  * the entire message is aborted, and the device is deselected.
3839  * Until returning from the associated message completion callback,
3840  * no other spi_message queued to that device will be processed.
3841  * (This rule applies equally to all the synchronous transfer calls,
3842  * which are wrappers around this core asynchronous primitive.)
3843  *
3844  * Return: zero on success, else a negative error code.
3845  */
3846 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3847 {
3848 	struct spi_controller *ctlr = spi->controller;
3849 	int ret;
3850 	unsigned long flags;
3851 
3852 	ret = __spi_validate(spi, message);
3853 	if (ret != 0)
3854 		return ret;
3855 
3856 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3857 
3858 	ret = __spi_async(spi, message);
3859 
3860 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3861 
3862 	return ret;
3863 
3864 }
3865 EXPORT_SYMBOL_GPL(spi_async_locked);
3866 
3867 /*-------------------------------------------------------------------------*/
3868 
3869 /* Utility methods for SPI protocol drivers, layered on
3870  * top of the core.  Some other utility methods are defined as
3871  * inline functions.
3872  */
3873 
3874 static void spi_complete(void *arg)
3875 {
3876 	complete(arg);
3877 }
3878 
3879 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3880 {
3881 	DECLARE_COMPLETION_ONSTACK(done);
3882 	int status;
3883 	struct spi_controller *ctlr = spi->controller;
3884 	unsigned long flags;
3885 
3886 	status = __spi_validate(spi, message);
3887 	if (status != 0)
3888 		return status;
3889 
3890 	message->complete = spi_complete;
3891 	message->context = &done;
3892 	message->spi = spi;
3893 
3894 	SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3895 	SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3896 
3897 	/* If we're not using the legacy transfer method then we will
3898 	 * try to transfer in the calling context so special case.
3899 	 * This code would be less tricky if we could remove the
3900 	 * support for driver implemented message queues.
3901 	 */
3902 	if (ctlr->transfer == spi_queued_transfer) {
3903 		spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3904 
3905 		trace_spi_message_submit(message);
3906 
3907 		status = __spi_queued_transfer(spi, message, false);
3908 
3909 		spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3910 	} else {
3911 		status = spi_async_locked(spi, message);
3912 	}
3913 
3914 	if (status == 0) {
3915 		/* Push out the messages in the calling context if we
3916 		 * can.
3917 		 */
3918 		if (ctlr->transfer == spi_queued_transfer) {
3919 			SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3920 						       spi_sync_immediate);
3921 			SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3922 						       spi_sync_immediate);
3923 			__spi_pump_messages(ctlr, false);
3924 		}
3925 
3926 		wait_for_completion(&done);
3927 		status = message->status;
3928 	}
3929 	message->context = NULL;
3930 	return status;
3931 }
3932 
3933 /**
3934  * spi_sync - blocking/synchronous SPI data transfers
3935  * @spi: device with which data will be exchanged
3936  * @message: describes the data transfers
3937  * Context: can sleep
3938  *
3939  * This call may only be used from a context that may sleep.  The sleep
3940  * is non-interruptible, and has no timeout.  Low-overhead controller
3941  * drivers may DMA directly into and out of the message buffers.
3942  *
3943  * Note that the SPI device's chip select is active during the message,
3944  * and then is normally disabled between messages.  Drivers for some
3945  * frequently-used devices may want to minimize costs of selecting a chip,
3946  * by leaving it selected in anticipation that the next message will go
3947  * to the same chip.  (That may increase power usage.)
3948  *
3949  * Also, the caller is guaranteeing that the memory associated with the
3950  * message will not be freed before this call returns.
3951  *
3952  * Return: zero on success, else a negative error code.
3953  */
3954 int spi_sync(struct spi_device *spi, struct spi_message *message)
3955 {
3956 	int ret;
3957 
3958 	mutex_lock(&spi->controller->bus_lock_mutex);
3959 	ret = __spi_sync(spi, message);
3960 	mutex_unlock(&spi->controller->bus_lock_mutex);
3961 
3962 	return ret;
3963 }
3964 EXPORT_SYMBOL_GPL(spi_sync);
3965 
3966 /**
3967  * spi_sync_locked - version of spi_sync with exclusive bus usage
3968  * @spi: device with which data will be exchanged
3969  * @message: describes the data transfers
3970  * Context: can sleep
3971  *
3972  * This call may only be used from a context that may sleep.  The sleep
3973  * is non-interruptible, and has no timeout.  Low-overhead controller
3974  * drivers may DMA directly into and out of the message buffers.
3975  *
3976  * This call should be used by drivers that require exclusive access to the
3977  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3978  * be released by a spi_bus_unlock call when the exclusive access is over.
3979  *
3980  * Return: zero on success, else a negative error code.
3981  */
3982 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3983 {
3984 	return __spi_sync(spi, message);
3985 }
3986 EXPORT_SYMBOL_GPL(spi_sync_locked);
3987 
3988 /**
3989  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3990  * @ctlr: SPI bus master that should be locked for exclusive bus access
3991  * Context: can sleep
3992  *
3993  * This call may only be used from a context that may sleep.  The sleep
3994  * is non-interruptible, and has no timeout.
3995  *
3996  * This call should be used by drivers that require exclusive access to the
3997  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3998  * exclusive access is over. Data transfer must be done by spi_sync_locked
3999  * and spi_async_locked calls when the SPI bus lock is held.
4000  *
4001  * Return: always zero.
4002  */
4003 int spi_bus_lock(struct spi_controller *ctlr)
4004 {
4005 	unsigned long flags;
4006 
4007 	mutex_lock(&ctlr->bus_lock_mutex);
4008 
4009 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4010 	ctlr->bus_lock_flag = 1;
4011 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4012 
4013 	/* mutex remains locked until spi_bus_unlock is called */
4014 
4015 	return 0;
4016 }
4017 EXPORT_SYMBOL_GPL(spi_bus_lock);
4018 
4019 /**
4020  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4021  * @ctlr: SPI bus master that was locked for exclusive bus access
4022  * Context: can sleep
4023  *
4024  * This call may only be used from a context that may sleep.  The sleep
4025  * is non-interruptible, and has no timeout.
4026  *
4027  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4028  * call.
4029  *
4030  * Return: always zero.
4031  */
4032 int spi_bus_unlock(struct spi_controller *ctlr)
4033 {
4034 	ctlr->bus_lock_flag = 0;
4035 
4036 	mutex_unlock(&ctlr->bus_lock_mutex);
4037 
4038 	return 0;
4039 }
4040 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4041 
4042 /* portable code must never pass more than 32 bytes */
4043 #define	SPI_BUFSIZ	max(32, SMP_CACHE_BYTES)
4044 
4045 static u8	*buf;
4046 
4047 /**
4048  * spi_write_then_read - SPI synchronous write followed by read
4049  * @spi: device with which data will be exchanged
4050  * @txbuf: data to be written (need not be dma-safe)
4051  * @n_tx: size of txbuf, in bytes
4052  * @rxbuf: buffer into which data will be read (need not be dma-safe)
4053  * @n_rx: size of rxbuf, in bytes
4054  * Context: can sleep
4055  *
4056  * This performs a half duplex MicroWire style transaction with the
4057  * device, sending txbuf and then reading rxbuf.  The return value
4058  * is zero for success, else a negative errno status code.
4059  * This call may only be used from a context that may sleep.
4060  *
4061  * Parameters to this routine are always copied using a small buffer.
4062  * Performance-sensitive or bulk transfer code should instead use
4063  * spi_{async,sync}() calls with dma-safe buffers.
4064  *
4065  * Return: zero on success, else a negative error code.
4066  */
4067 int spi_write_then_read(struct spi_device *spi,
4068 		const void *txbuf, unsigned n_tx,
4069 		void *rxbuf, unsigned n_rx)
4070 {
4071 	static DEFINE_MUTEX(lock);
4072 
4073 	int			status;
4074 	struct spi_message	message;
4075 	struct spi_transfer	x[2];
4076 	u8			*local_buf;
4077 
4078 	/* Use preallocated DMA-safe buffer if we can.  We can't avoid
4079 	 * copying here, (as a pure convenience thing), but we can
4080 	 * keep heap costs out of the hot path unless someone else is
4081 	 * using the pre-allocated buffer or the transfer is too large.
4082 	 */
4083 	if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4084 		local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4085 				    GFP_KERNEL | GFP_DMA);
4086 		if (!local_buf)
4087 			return -ENOMEM;
4088 	} else {
4089 		local_buf = buf;
4090 	}
4091 
4092 	spi_message_init(&message);
4093 	memset(x, 0, sizeof(x));
4094 	if (n_tx) {
4095 		x[0].len = n_tx;
4096 		spi_message_add_tail(&x[0], &message);
4097 	}
4098 	if (n_rx) {
4099 		x[1].len = n_rx;
4100 		spi_message_add_tail(&x[1], &message);
4101 	}
4102 
4103 	memcpy(local_buf, txbuf, n_tx);
4104 	x[0].tx_buf = local_buf;
4105 	x[1].rx_buf = local_buf + n_tx;
4106 
4107 	/* do the i/o */
4108 	status = spi_sync(spi, &message);
4109 	if (status == 0)
4110 		memcpy(rxbuf, x[1].rx_buf, n_rx);
4111 
4112 	if (x[0].tx_buf == buf)
4113 		mutex_unlock(&lock);
4114 	else
4115 		kfree(local_buf);
4116 
4117 	return status;
4118 }
4119 EXPORT_SYMBOL_GPL(spi_write_then_read);
4120 
4121 /*-------------------------------------------------------------------------*/
4122 
4123 #if IS_ENABLED(CONFIG_OF)
4124 /* must call put_device() when done with returned spi_device device */
4125 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4126 {
4127 	struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4128 
4129 	return dev ? to_spi_device(dev) : NULL;
4130 }
4131 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
4132 #endif /* IS_ENABLED(CONFIG_OF) */
4133 
4134 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4135 /* the spi controllers are not using spi_bus, so we find it with another way */
4136 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4137 {
4138 	struct device *dev;
4139 
4140 	dev = class_find_device_by_of_node(&spi_master_class, node);
4141 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4142 		dev = class_find_device_by_of_node(&spi_slave_class, node);
4143 	if (!dev)
4144 		return NULL;
4145 
4146 	/* reference got in class_find_device */
4147 	return container_of(dev, struct spi_controller, dev);
4148 }
4149 
4150 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4151 			 void *arg)
4152 {
4153 	struct of_reconfig_data *rd = arg;
4154 	struct spi_controller *ctlr;
4155 	struct spi_device *spi;
4156 
4157 	switch (of_reconfig_get_state_change(action, arg)) {
4158 	case OF_RECONFIG_CHANGE_ADD:
4159 		ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4160 		if (ctlr == NULL)
4161 			return NOTIFY_OK;	/* not for us */
4162 
4163 		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4164 			put_device(&ctlr->dev);
4165 			return NOTIFY_OK;
4166 		}
4167 
4168 		spi = of_register_spi_device(ctlr, rd->dn);
4169 		put_device(&ctlr->dev);
4170 
4171 		if (IS_ERR(spi)) {
4172 			pr_err("%s: failed to create for '%pOF'\n",
4173 					__func__, rd->dn);
4174 			of_node_clear_flag(rd->dn, OF_POPULATED);
4175 			return notifier_from_errno(PTR_ERR(spi));
4176 		}
4177 		break;
4178 
4179 	case OF_RECONFIG_CHANGE_REMOVE:
4180 		/* already depopulated? */
4181 		if (!of_node_check_flag(rd->dn, OF_POPULATED))
4182 			return NOTIFY_OK;
4183 
4184 		/* find our device by node */
4185 		spi = of_find_spi_device_by_node(rd->dn);
4186 		if (spi == NULL)
4187 			return NOTIFY_OK;	/* no? not meant for us */
4188 
4189 		/* unregister takes one ref away */
4190 		spi_unregister_device(spi);
4191 
4192 		/* and put the reference of the find */
4193 		put_device(&spi->dev);
4194 		break;
4195 	}
4196 
4197 	return NOTIFY_OK;
4198 }
4199 
4200 static struct notifier_block spi_of_notifier = {
4201 	.notifier_call = of_spi_notify,
4202 };
4203 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4204 extern struct notifier_block spi_of_notifier;
4205 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4206 
4207 #if IS_ENABLED(CONFIG_ACPI)
4208 static int spi_acpi_controller_match(struct device *dev, const void *data)
4209 {
4210 	return ACPI_COMPANION(dev->parent) == data;
4211 }
4212 
4213 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4214 {
4215 	struct device *dev;
4216 
4217 	dev = class_find_device(&spi_master_class, NULL, adev,
4218 				spi_acpi_controller_match);
4219 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4220 		dev = class_find_device(&spi_slave_class, NULL, adev,
4221 					spi_acpi_controller_match);
4222 	if (!dev)
4223 		return NULL;
4224 
4225 	return container_of(dev, struct spi_controller, dev);
4226 }
4227 
4228 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4229 {
4230 	struct device *dev;
4231 
4232 	dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4233 	return to_spi_device(dev);
4234 }
4235 
4236 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4237 			   void *arg)
4238 {
4239 	struct acpi_device *adev = arg;
4240 	struct spi_controller *ctlr;
4241 	struct spi_device *spi;
4242 
4243 	switch (value) {
4244 	case ACPI_RECONFIG_DEVICE_ADD:
4245 		ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4246 		if (!ctlr)
4247 			break;
4248 
4249 		acpi_register_spi_device(ctlr, adev);
4250 		put_device(&ctlr->dev);
4251 		break;
4252 	case ACPI_RECONFIG_DEVICE_REMOVE:
4253 		if (!acpi_device_enumerated(adev))
4254 			break;
4255 
4256 		spi = acpi_spi_find_device_by_adev(adev);
4257 		if (!spi)
4258 			break;
4259 
4260 		spi_unregister_device(spi);
4261 		put_device(&spi->dev);
4262 		break;
4263 	}
4264 
4265 	return NOTIFY_OK;
4266 }
4267 
4268 static struct notifier_block spi_acpi_notifier = {
4269 	.notifier_call = acpi_spi_notify,
4270 };
4271 #else
4272 extern struct notifier_block spi_acpi_notifier;
4273 #endif
4274 
4275 static int __init spi_init(void)
4276 {
4277 	int	status;
4278 
4279 	buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4280 	if (!buf) {
4281 		status = -ENOMEM;
4282 		goto err0;
4283 	}
4284 
4285 	status = bus_register(&spi_bus_type);
4286 	if (status < 0)
4287 		goto err1;
4288 
4289 	status = class_register(&spi_master_class);
4290 	if (status < 0)
4291 		goto err2;
4292 
4293 	if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4294 		status = class_register(&spi_slave_class);
4295 		if (status < 0)
4296 			goto err3;
4297 	}
4298 
4299 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4300 		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4301 	if (IS_ENABLED(CONFIG_ACPI))
4302 		WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4303 
4304 	return 0;
4305 
4306 err3:
4307 	class_unregister(&spi_master_class);
4308 err2:
4309 	bus_unregister(&spi_bus_type);
4310 err1:
4311 	kfree(buf);
4312 	buf = NULL;
4313 err0:
4314 	return status;
4315 }
4316 
4317 /* board_info is normally registered in arch_initcall(),
4318  * but even essential drivers wait till later
4319  *
4320  * REVISIT only boardinfo really needs static linking. the rest (device and
4321  * driver registration) _could_ be dynamically linked (modular) ... costs
4322  * include needing to have boardinfo data structures be much more public.
4323  */
4324 postcore_initcall(spi_init);
4325