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1/*
2 * nvmem framework core.
3 *
4 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
5 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 and
9 * only version 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/device.h>
18#include <linux/export.h>
19#include <linux/fs.h>
20#include <linux/idr.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/nvmem-consumer.h>
24#include <linux/nvmem-provider.h>
25#include <linux/of.h>
26#include <linux/slab.h>
27
28struct nvmem_device {
29 const char *name;
30 struct module *owner;
31 struct device dev;
32 int stride;
33 int word_size;
34 int ncells;
35 int id;
36 int users;
37 size_t size;
38 bool read_only;
39 int flags;
40 struct bin_attribute eeprom;
41 struct device *base_dev;
42 nvmem_reg_read_t reg_read;
43 nvmem_reg_write_t reg_write;
44 void *priv;
45};
46
47#define FLAG_COMPAT BIT(0)
48
49struct nvmem_cell {
50 const char *name;
51 int offset;
52 int bytes;
53 int bit_offset;
54 int nbits;
55 struct nvmem_device *nvmem;
56 struct list_head node;
57};
58
59static DEFINE_MUTEX(nvmem_mutex);
60static DEFINE_IDA(nvmem_ida);
61
62static LIST_HEAD(nvmem_cells);
63static DEFINE_MUTEX(nvmem_cells_mutex);
64
65#ifdef CONFIG_DEBUG_LOCK_ALLOC
66static struct lock_class_key eeprom_lock_key;
67#endif
68
69#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
70static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
71 void *val, size_t bytes)
72{
73 if (nvmem->reg_read)
74 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
75
76 return -EINVAL;
77}
78
79static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
80 void *val, size_t bytes)
81{
82 if (nvmem->reg_write)
83 return nvmem->reg_write(nvmem->priv, offset, val, bytes);
84
85 return -EINVAL;
86}
87
88static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
89 struct bin_attribute *attr,
90 char *buf, loff_t pos, size_t count)
91{
92 struct device *dev;
93 struct nvmem_device *nvmem;
94 int rc;
95
96 if (attr->private)
97 dev = attr->private;
98 else
99 dev = container_of(kobj, struct device, kobj);
100 nvmem = to_nvmem_device(dev);
101
102 /* Stop the user from reading */
103 if (pos >= nvmem->size)
104 return 0;
105
106 if (count < nvmem->word_size)
107 return -EINVAL;
108
109 if (pos + count > nvmem->size)
110 count = nvmem->size - pos;
111
112 count = round_down(count, nvmem->word_size);
113
114 rc = nvmem_reg_read(nvmem, pos, buf, count);
115
116 if (rc)
117 return rc;
118
119 return count;
120}
121
122static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
123 struct bin_attribute *attr,
124 char *buf, loff_t pos, size_t count)
125{
126 struct device *dev;
127 struct nvmem_device *nvmem;
128 int rc;
129
130 if (attr->private)
131 dev = attr->private;
132 else
133 dev = container_of(kobj, struct device, kobj);
134 nvmem = to_nvmem_device(dev);
135
136 /* Stop the user from writing */
137 if (pos >= nvmem->size)
138 return -EFBIG;
139
140 if (count < nvmem->word_size)
141 return -EINVAL;
142
143 if (pos + count > nvmem->size)
144 count = nvmem->size - pos;
145
146 count = round_down(count, nvmem->word_size);
147
148 rc = nvmem_reg_write(nvmem, pos, buf, count);
149
150 if (rc)
151 return rc;
152
153 return count;
154}
155
156/* default read/write permissions */
157static struct bin_attribute bin_attr_rw_nvmem = {
158 .attr = {
159 .name = "nvmem",
160 .mode = S_IWUSR | S_IRUGO,
161 },
162 .read = bin_attr_nvmem_read,
163 .write = bin_attr_nvmem_write,
164};
165
166static struct bin_attribute *nvmem_bin_rw_attributes[] = {
167 &bin_attr_rw_nvmem,
168 NULL,
169};
170
171static const struct attribute_group nvmem_bin_rw_group = {
172 .bin_attrs = nvmem_bin_rw_attributes,
173};
174
175static const struct attribute_group *nvmem_rw_dev_groups[] = {
176 &nvmem_bin_rw_group,
177 NULL,
178};
179
180/* read only permission */
181static struct bin_attribute bin_attr_ro_nvmem = {
182 .attr = {
183 .name = "nvmem",
184 .mode = S_IRUGO,
185 },
186 .read = bin_attr_nvmem_read,
187};
188
189static struct bin_attribute *nvmem_bin_ro_attributes[] = {
190 &bin_attr_ro_nvmem,
191 NULL,
192};
193
194static const struct attribute_group nvmem_bin_ro_group = {
195 .bin_attrs = nvmem_bin_ro_attributes,
196};
197
198static const struct attribute_group *nvmem_ro_dev_groups[] = {
199 &nvmem_bin_ro_group,
200 NULL,
201};
202
203/* default read/write permissions, root only */
204static struct bin_attribute bin_attr_rw_root_nvmem = {
205 .attr = {
206 .name = "nvmem",
207 .mode = S_IWUSR | S_IRUSR,
208 },
209 .read = bin_attr_nvmem_read,
210 .write = bin_attr_nvmem_write,
211};
212
213static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
214 &bin_attr_rw_root_nvmem,
215 NULL,
216};
217
218static const struct attribute_group nvmem_bin_rw_root_group = {
219 .bin_attrs = nvmem_bin_rw_root_attributes,
220};
221
222static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
223 &nvmem_bin_rw_root_group,
224 NULL,
225};
226
227/* read only permission, root only */
228static struct bin_attribute bin_attr_ro_root_nvmem = {
229 .attr = {
230 .name = "nvmem",
231 .mode = S_IRUSR,
232 },
233 .read = bin_attr_nvmem_read,
234};
235
236static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
237 &bin_attr_ro_root_nvmem,
238 NULL,
239};
240
241static const struct attribute_group nvmem_bin_ro_root_group = {
242 .bin_attrs = nvmem_bin_ro_root_attributes,
243};
244
245static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
246 &nvmem_bin_ro_root_group,
247 NULL,
248};
249
250static void nvmem_release(struct device *dev)
251{
252 struct nvmem_device *nvmem = to_nvmem_device(dev);
253
254 ida_simple_remove(&nvmem_ida, nvmem->id);
255 kfree(nvmem);
256}
257
258static const struct device_type nvmem_provider_type = {
259 .release = nvmem_release,
260};
261
262static struct bus_type nvmem_bus_type = {
263 .name = "nvmem",
264};
265
266static int of_nvmem_match(struct device *dev, void *nvmem_np)
267{
268 return dev->of_node == nvmem_np;
269}
270
271static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
272{
273 struct device *d;
274
275 if (!nvmem_np)
276 return NULL;
277
278 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
279
280 if (!d)
281 return NULL;
282
283 return to_nvmem_device(d);
284}
285
286static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
287{
288 struct nvmem_cell *p;
289
290 mutex_lock(&nvmem_cells_mutex);
291
292 list_for_each_entry(p, &nvmem_cells, node)
293 if (!strcmp(p->name, cell_id)) {
294 mutex_unlock(&nvmem_cells_mutex);
295 return p;
296 }
297
298 mutex_unlock(&nvmem_cells_mutex);
299
300 return NULL;
301}
302
303static void nvmem_cell_drop(struct nvmem_cell *cell)
304{
305 mutex_lock(&nvmem_cells_mutex);
306 list_del(&cell->node);
307 mutex_unlock(&nvmem_cells_mutex);
308 kfree(cell);
309}
310
311static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
312{
313 struct nvmem_cell *cell;
314 struct list_head *p, *n;
315
316 list_for_each_safe(p, n, &nvmem_cells) {
317 cell = list_entry(p, struct nvmem_cell, node);
318 if (cell->nvmem == nvmem)
319 nvmem_cell_drop(cell);
320 }
321}
322
323static void nvmem_cell_add(struct nvmem_cell *cell)
324{
325 mutex_lock(&nvmem_cells_mutex);
326 list_add_tail(&cell->node, &nvmem_cells);
327 mutex_unlock(&nvmem_cells_mutex);
328}
329
330static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
331 const struct nvmem_cell_info *info,
332 struct nvmem_cell *cell)
333{
334 cell->nvmem = nvmem;
335 cell->offset = info->offset;
336 cell->bytes = info->bytes;
337 cell->name = info->name;
338
339 cell->bit_offset = info->bit_offset;
340 cell->nbits = info->nbits;
341
342 if (cell->nbits)
343 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
344 BITS_PER_BYTE);
345
346 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
347 dev_err(&nvmem->dev,
348 "cell %s unaligned to nvmem stride %d\n",
349 cell->name, nvmem->stride);
350 return -EINVAL;
351 }
352
353 return 0;
354}
355
356static int nvmem_add_cells(struct nvmem_device *nvmem,
357 const struct nvmem_config *cfg)
358{
359 struct nvmem_cell **cells;
360 const struct nvmem_cell_info *info = cfg->cells;
361 int i, rval;
362
363 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
364 if (!cells)
365 return -ENOMEM;
366
367 for (i = 0; i < cfg->ncells; i++) {
368 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
369 if (!cells[i]) {
370 rval = -ENOMEM;
371 goto err;
372 }
373
374 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
375 if (rval) {
376 kfree(cells[i]);
377 goto err;
378 }
379
380 nvmem_cell_add(cells[i]);
381 }
382
383 nvmem->ncells = cfg->ncells;
384 /* remove tmp array */
385 kfree(cells);
386
387 return 0;
388err:
389 while (i--)
390 nvmem_cell_drop(cells[i]);
391
392 kfree(cells);
393
394 return rval;
395}
396
397/*
398 * nvmem_setup_compat() - Create an additional binary entry in
399 * drivers sys directory, to be backwards compatible with the older
400 * drivers/misc/eeprom drivers.
401 */
402static int nvmem_setup_compat(struct nvmem_device *nvmem,
403 const struct nvmem_config *config)
404{
405 int rval;
406
407 if (!config->base_dev)
408 return -EINVAL;
409
410 if (nvmem->read_only)
411 nvmem->eeprom = bin_attr_ro_root_nvmem;
412 else
413 nvmem->eeprom = bin_attr_rw_root_nvmem;
414 nvmem->eeprom.attr.name = "eeprom";
415 nvmem->eeprom.size = nvmem->size;
416#ifdef CONFIG_DEBUG_LOCK_ALLOC
417 nvmem->eeprom.attr.key = &eeprom_lock_key;
418#endif
419 nvmem->eeprom.private = &nvmem->dev;
420 nvmem->base_dev = config->base_dev;
421
422 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
423 if (rval) {
424 dev_err(&nvmem->dev,
425 "Failed to create eeprom binary file %d\n", rval);
426 return rval;
427 }
428
429 nvmem->flags |= FLAG_COMPAT;
430
431 return 0;
432}
433
434/**
435 * nvmem_register() - Register a nvmem device for given nvmem_config.
436 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
437 *
438 * @config: nvmem device configuration with which nvmem device is created.
439 *
440 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
441 * on success.
442 */
443
444struct nvmem_device *nvmem_register(const struct nvmem_config *config)
445{
446 struct nvmem_device *nvmem;
447 int rval;
448
449 if (!config->dev)
450 return ERR_PTR(-EINVAL);
451
452 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
453 if (!nvmem)
454 return ERR_PTR(-ENOMEM);
455
456 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
457 if (rval < 0) {
458 kfree(nvmem);
459 return ERR_PTR(rval);
460 }
461
462 nvmem->id = rval;
463 nvmem->owner = config->owner;
464 if (!nvmem->owner && config->dev->driver)
465 nvmem->owner = config->dev->driver->owner;
466 nvmem->stride = config->stride ?: 1;
467 nvmem->word_size = config->word_size ?: 1;
468 nvmem->size = config->size;
469 nvmem->dev.type = &nvmem_provider_type;
470 nvmem->dev.bus = &nvmem_bus_type;
471 nvmem->dev.parent = config->dev;
472 nvmem->priv = config->priv;
473 nvmem->reg_read = config->reg_read;
474 nvmem->reg_write = config->reg_write;
475 nvmem->dev.of_node = config->dev->of_node;
476
477 if (config->id == -1 && config->name) {
478 dev_set_name(&nvmem->dev, "%s", config->name);
479 } else {
480 dev_set_name(&nvmem->dev, "%s%d",
481 config->name ? : "nvmem",
482 config->name ? config->id : nvmem->id);
483 }
484
485 nvmem->read_only = device_property_present(config->dev, "read-only") |
486 config->read_only;
487
488 if (config->root_only)
489 nvmem->dev.groups = nvmem->read_only ?
490 nvmem_ro_root_dev_groups :
491 nvmem_rw_root_dev_groups;
492 else
493 nvmem->dev.groups = nvmem->read_only ?
494 nvmem_ro_dev_groups :
495 nvmem_rw_dev_groups;
496
497 device_initialize(&nvmem->dev);
498
499 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
500
501 rval = device_add(&nvmem->dev);
502 if (rval)
503 goto err_put_device;
504
505 if (config->compat) {
506 rval = nvmem_setup_compat(nvmem, config);
507 if (rval)
508 goto err_device_del;
509 }
510
511 if (config->cells)
512 nvmem_add_cells(nvmem, config);
513
514 return nvmem;
515
516err_device_del:
517 device_del(&nvmem->dev);
518err_put_device:
519 put_device(&nvmem->dev);
520
521 return ERR_PTR(rval);
522}
523EXPORT_SYMBOL_GPL(nvmem_register);
524
525/**
526 * nvmem_unregister() - Unregister previously registered nvmem device
527 *
528 * @nvmem: Pointer to previously registered nvmem device.
529 *
530 * Return: Will be an negative on error or a zero on success.
531 */
532int nvmem_unregister(struct nvmem_device *nvmem)
533{
534 mutex_lock(&nvmem_mutex);
535 if (nvmem->users) {
536 mutex_unlock(&nvmem_mutex);
537 return -EBUSY;
538 }
539 mutex_unlock(&nvmem_mutex);
540
541 if (nvmem->flags & FLAG_COMPAT)
542 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
543
544 nvmem_device_remove_all_cells(nvmem);
545 device_del(&nvmem->dev);
546 put_device(&nvmem->dev);
547
548 return 0;
549}
550EXPORT_SYMBOL_GPL(nvmem_unregister);
551
552static void devm_nvmem_release(struct device *dev, void *res)
553{
554 WARN_ON(nvmem_unregister(*(struct nvmem_device **)res));
555}
556
557/**
558 * devm_nvmem_register() - Register a managed nvmem device for given
559 * nvmem_config.
560 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
561 *
562 * @config: nvmem device configuration with which nvmem device is created.
563 *
564 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
565 * on success.
566 */
567struct nvmem_device *devm_nvmem_register(struct device *dev,
568 const struct nvmem_config *config)
569{
570 struct nvmem_device **ptr, *nvmem;
571
572 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
573 if (!ptr)
574 return ERR_PTR(-ENOMEM);
575
576 nvmem = nvmem_register(config);
577
578 if (!IS_ERR(nvmem)) {
579 *ptr = nvmem;
580 devres_add(dev, ptr);
581 } else {
582 devres_free(ptr);
583 }
584
585 return nvmem;
586}
587EXPORT_SYMBOL_GPL(devm_nvmem_register);
588
589static int devm_nvmem_match(struct device *dev, void *res, void *data)
590{
591 struct nvmem_device **r = res;
592
593 return *r == data;
594}
595
596/**
597 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
598 * device.
599 *
600 * @nvmem: Pointer to previously registered nvmem device.
601 *
602 * Return: Will be an negative on error or a zero on success.
603 */
604int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
605{
606 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
607}
608EXPORT_SYMBOL(devm_nvmem_unregister);
609
610
611static struct nvmem_device *__nvmem_device_get(struct device_node *np,
612 struct nvmem_cell **cellp,
613 const char *cell_id)
614{
615 struct nvmem_device *nvmem = NULL;
616
617 mutex_lock(&nvmem_mutex);
618
619 if (np) {
620 nvmem = of_nvmem_find(np);
621 if (!nvmem) {
622 mutex_unlock(&nvmem_mutex);
623 return ERR_PTR(-EPROBE_DEFER);
624 }
625 } else {
626 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
627
628 if (cell) {
629 nvmem = cell->nvmem;
630 *cellp = cell;
631 }
632
633 if (!nvmem) {
634 mutex_unlock(&nvmem_mutex);
635 return ERR_PTR(-ENOENT);
636 }
637 }
638
639 nvmem->users++;
640 mutex_unlock(&nvmem_mutex);
641
642 if (!try_module_get(nvmem->owner)) {
643 dev_err(&nvmem->dev,
644 "could not increase module refcount for cell %s\n",
645 nvmem->name);
646
647 mutex_lock(&nvmem_mutex);
648 nvmem->users--;
649 mutex_unlock(&nvmem_mutex);
650
651 return ERR_PTR(-EINVAL);
652 }
653
654 return nvmem;
655}
656
657static void __nvmem_device_put(struct nvmem_device *nvmem)
658{
659 module_put(nvmem->owner);
660 mutex_lock(&nvmem_mutex);
661 nvmem->users--;
662 mutex_unlock(&nvmem_mutex);
663}
664
665static struct nvmem_device *nvmem_find(const char *name)
666{
667 struct device *d;
668
669 d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
670
671 if (!d)
672 return NULL;
673
674 return to_nvmem_device(d);
675}
676
677#if IS_ENABLED(CONFIG_OF)
678/**
679 * of_nvmem_device_get() - Get nvmem device from a given id
680 *
681 * @np: Device tree node that uses the nvmem device.
682 * @id: nvmem name from nvmem-names property.
683 *
684 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
685 * on success.
686 */
687struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
688{
689
690 struct device_node *nvmem_np;
691 int index;
692
693 index = of_property_match_string(np, "nvmem-names", id);
694
695 nvmem_np = of_parse_phandle(np, "nvmem", index);
696 if (!nvmem_np)
697 return ERR_PTR(-EINVAL);
698
699 return __nvmem_device_get(nvmem_np, NULL, NULL);
700}
701EXPORT_SYMBOL_GPL(of_nvmem_device_get);
702#endif
703
704/**
705 * nvmem_device_get() - Get nvmem device from a given id
706 *
707 * @dev: Device that uses the nvmem device.
708 * @dev_name: name of the requested nvmem device.
709 *
710 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
711 * on success.
712 */
713struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
714{
715 if (dev->of_node) { /* try dt first */
716 struct nvmem_device *nvmem;
717
718 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
719
720 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
721 return nvmem;
722
723 }
724
725 return nvmem_find(dev_name);
726}
727EXPORT_SYMBOL_GPL(nvmem_device_get);
728
729static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
730{
731 struct nvmem_device **nvmem = res;
732
733 if (WARN_ON(!nvmem || !*nvmem))
734 return 0;
735
736 return *nvmem == data;
737}
738
739static void devm_nvmem_device_release(struct device *dev, void *res)
740{
741 nvmem_device_put(*(struct nvmem_device **)res);
742}
743
744/**
745 * devm_nvmem_device_put() - put alredy got nvmem device
746 *
747 * @dev: Device that uses the nvmem device.
748 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
749 * that needs to be released.
750 */
751void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
752{
753 int ret;
754
755 ret = devres_release(dev, devm_nvmem_device_release,
756 devm_nvmem_device_match, nvmem);
757
758 WARN_ON(ret);
759}
760EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
761
762/**
763 * nvmem_device_put() - put alredy got nvmem device
764 *
765 * @nvmem: pointer to nvmem device that needs to be released.
766 */
767void nvmem_device_put(struct nvmem_device *nvmem)
768{
769 __nvmem_device_put(nvmem);
770}
771EXPORT_SYMBOL_GPL(nvmem_device_put);
772
773/**
774 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
775 *
776 * @dev: Device that requests the nvmem device.
777 * @id: name id for the requested nvmem device.
778 *
779 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
780 * on success. The nvmem_cell will be freed by the automatically once the
781 * device is freed.
782 */
783struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
784{
785 struct nvmem_device **ptr, *nvmem;
786
787 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
788 if (!ptr)
789 return ERR_PTR(-ENOMEM);
790
791 nvmem = nvmem_device_get(dev, id);
792 if (!IS_ERR(nvmem)) {
793 *ptr = nvmem;
794 devres_add(dev, ptr);
795 } else {
796 devres_free(ptr);
797 }
798
799 return nvmem;
800}
801EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
802
803static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
804{
805 struct nvmem_cell *cell = NULL;
806 struct nvmem_device *nvmem;
807
808 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
809 if (IS_ERR(nvmem))
810 return ERR_CAST(nvmem);
811
812 return cell;
813}
814
815#if IS_ENABLED(CONFIG_OF)
816/**
817 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
818 *
819 * @np: Device tree node that uses the nvmem cell.
820 * @name: nvmem cell name from nvmem-cell-names property, or NULL
821 * for the cell at index 0 (the lone cell with no accompanying
822 * nvmem-cell-names property).
823 *
824 * Return: Will be an ERR_PTR() on error or a valid pointer
825 * to a struct nvmem_cell. The nvmem_cell will be freed by the
826 * nvmem_cell_put().
827 */
828struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
829 const char *name)
830{
831 struct device_node *cell_np, *nvmem_np;
832 struct nvmem_cell *cell;
833 struct nvmem_device *nvmem;
834 const __be32 *addr;
835 int rval, len;
836 int index = 0;
837
838 /* if cell name exists, find index to the name */
839 if (name)
840 index = of_property_match_string(np, "nvmem-cell-names", name);
841
842 cell_np = of_parse_phandle(np, "nvmem-cells", index);
843 if (!cell_np)
844 return ERR_PTR(-EINVAL);
845
846 nvmem_np = of_get_next_parent(cell_np);
847 if (!nvmem_np)
848 return ERR_PTR(-EINVAL);
849
850 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
851 of_node_put(nvmem_np);
852 if (IS_ERR(nvmem))
853 return ERR_CAST(nvmem);
854
855 addr = of_get_property(cell_np, "reg", &len);
856 if (!addr || (len < 2 * sizeof(u32))) {
857 dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n",
858 cell_np);
859 rval = -EINVAL;
860 goto err_mem;
861 }
862
863 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
864 if (!cell) {
865 rval = -ENOMEM;
866 goto err_mem;
867 }
868
869 cell->nvmem = nvmem;
870 cell->offset = be32_to_cpup(addr++);
871 cell->bytes = be32_to_cpup(addr);
872 cell->name = cell_np->name;
873
874 addr = of_get_property(cell_np, "bits", &len);
875 if (addr && len == (2 * sizeof(u32))) {
876 cell->bit_offset = be32_to_cpup(addr++);
877 cell->nbits = be32_to_cpup(addr);
878 }
879
880 if (cell->nbits)
881 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
882 BITS_PER_BYTE);
883
884 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
885 dev_err(&nvmem->dev,
886 "cell %s unaligned to nvmem stride %d\n",
887 cell->name, nvmem->stride);
888 rval = -EINVAL;
889 goto err_sanity;
890 }
891
892 nvmem_cell_add(cell);
893
894 return cell;
895
896err_sanity:
897 kfree(cell);
898
899err_mem:
900 __nvmem_device_put(nvmem);
901
902 return ERR_PTR(rval);
903}
904EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
905#endif
906
907/**
908 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
909 *
910 * @dev: Device that requests the nvmem cell.
911 * @cell_id: nvmem cell name to get.
912 *
913 * Return: Will be an ERR_PTR() on error or a valid pointer
914 * to a struct nvmem_cell. The nvmem_cell will be freed by the
915 * nvmem_cell_put().
916 */
917struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
918{
919 struct nvmem_cell *cell;
920
921 if (dev->of_node) { /* try dt first */
922 cell = of_nvmem_cell_get(dev->of_node, cell_id);
923 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
924 return cell;
925 }
926
927 return nvmem_cell_get_from_list(cell_id);
928}
929EXPORT_SYMBOL_GPL(nvmem_cell_get);
930
931static void devm_nvmem_cell_release(struct device *dev, void *res)
932{
933 nvmem_cell_put(*(struct nvmem_cell **)res);
934}
935
936/**
937 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
938 *
939 * @dev: Device that requests the nvmem cell.
940 * @id: nvmem cell name id to get.
941 *
942 * Return: Will be an ERR_PTR() on error or a valid pointer
943 * to a struct nvmem_cell. The nvmem_cell will be freed by the
944 * automatically once the device is freed.
945 */
946struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
947{
948 struct nvmem_cell **ptr, *cell;
949
950 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
951 if (!ptr)
952 return ERR_PTR(-ENOMEM);
953
954 cell = nvmem_cell_get(dev, id);
955 if (!IS_ERR(cell)) {
956 *ptr = cell;
957 devres_add(dev, ptr);
958 } else {
959 devres_free(ptr);
960 }
961
962 return cell;
963}
964EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
965
966static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
967{
968 struct nvmem_cell **c = res;
969
970 if (WARN_ON(!c || !*c))
971 return 0;
972
973 return *c == data;
974}
975
976/**
977 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
978 * from devm_nvmem_cell_get.
979 *
980 * @dev: Device that requests the nvmem cell.
981 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
982 */
983void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
984{
985 int ret;
986
987 ret = devres_release(dev, devm_nvmem_cell_release,
988 devm_nvmem_cell_match, cell);
989
990 WARN_ON(ret);
991}
992EXPORT_SYMBOL(devm_nvmem_cell_put);
993
994/**
995 * nvmem_cell_put() - Release previously allocated nvmem cell.
996 *
997 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
998 */
999void nvmem_cell_put(struct nvmem_cell *cell)
1000{
1001 struct nvmem_device *nvmem = cell->nvmem;
1002
1003 __nvmem_device_put(nvmem);
1004 nvmem_cell_drop(cell);
1005}
1006EXPORT_SYMBOL_GPL(nvmem_cell_put);
1007
1008static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
1009{
1010 u8 *p, *b;
1011 int i, bit_offset = cell->bit_offset;
1012
1013 p = b = buf;
1014 if (bit_offset) {
1015 /* First shift */
1016 *b++ >>= bit_offset;
1017
1018 /* setup rest of the bytes if any */
1019 for (i = 1; i < cell->bytes; i++) {
1020 /* Get bits from next byte and shift them towards msb */
1021 *p |= *b << (BITS_PER_BYTE - bit_offset);
1022
1023 p = b;
1024 *b++ >>= bit_offset;
1025 }
1026
1027 /* result fits in less bytes */
1028 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
1029 *p-- = 0;
1030 }
1031 /* clear msb bits if any leftover in the last byte */
1032 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
1033}
1034
1035static int __nvmem_cell_read(struct nvmem_device *nvmem,
1036 struct nvmem_cell *cell,
1037 void *buf, size_t *len)
1038{
1039 int rc;
1040
1041 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1042
1043 if (rc)
1044 return rc;
1045
1046 /* shift bits in-place */
1047 if (cell->bit_offset || cell->nbits)
1048 nvmem_shift_read_buffer_in_place(cell, buf);
1049
1050 if (len)
1051 *len = cell->bytes;
1052
1053 return 0;
1054}
1055
1056/**
1057 * nvmem_cell_read() - Read a given nvmem cell
1058 *
1059 * @cell: nvmem cell to be read.
1060 * @len: pointer to length of cell which will be populated on successful read;
1061 * can be NULL.
1062 *
1063 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1064 * buffer should be freed by the consumer with a kfree().
1065 */
1066void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1067{
1068 struct nvmem_device *nvmem = cell->nvmem;
1069 u8 *buf;
1070 int rc;
1071
1072 if (!nvmem)
1073 return ERR_PTR(-EINVAL);
1074
1075 buf = kzalloc(cell->bytes, GFP_KERNEL);
1076 if (!buf)
1077 return ERR_PTR(-ENOMEM);
1078
1079 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1080 if (rc) {
1081 kfree(buf);
1082 return ERR_PTR(rc);
1083 }
1084
1085 return buf;
1086}
1087EXPORT_SYMBOL_GPL(nvmem_cell_read);
1088
1089static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1090 u8 *_buf, int len)
1091{
1092 struct nvmem_device *nvmem = cell->nvmem;
1093 int i, rc, nbits, bit_offset = cell->bit_offset;
1094 u8 v, *p, *buf, *b, pbyte, pbits;
1095
1096 nbits = cell->nbits;
1097 buf = kzalloc(cell->bytes, GFP_KERNEL);
1098 if (!buf)
1099 return ERR_PTR(-ENOMEM);
1100
1101 memcpy(buf, _buf, len);
1102 p = b = buf;
1103
1104 if (bit_offset) {
1105 pbyte = *b;
1106 *b <<= bit_offset;
1107
1108 /* setup the first byte with lsb bits from nvmem */
1109 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1110 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1111
1112 /* setup rest of the byte if any */
1113 for (i = 1; i < cell->bytes; i++) {
1114 /* Get last byte bits and shift them towards lsb */
1115 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1116 pbyte = *b;
1117 p = b;
1118 *b <<= bit_offset;
1119 *b++ |= pbits;
1120 }
1121 }
1122
1123 /* if it's not end on byte boundary */
1124 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1125 /* setup the last byte with msb bits from nvmem */
1126 rc = nvmem_reg_read(nvmem,
1127 cell->offset + cell->bytes - 1, &v, 1);
1128 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1129
1130 }
1131
1132 return buf;
1133}
1134
1135/**
1136 * nvmem_cell_write() - Write to a given nvmem cell
1137 *
1138 * @cell: nvmem cell to be written.
1139 * @buf: Buffer to be written.
1140 * @len: length of buffer to be written to nvmem cell.
1141 *
1142 * Return: length of bytes written or negative on failure.
1143 */
1144int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1145{
1146 struct nvmem_device *nvmem = cell->nvmem;
1147 int rc;
1148
1149 if (!nvmem || nvmem->read_only ||
1150 (cell->bit_offset == 0 && len != cell->bytes))
1151 return -EINVAL;
1152
1153 if (cell->bit_offset || cell->nbits) {
1154 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1155 if (IS_ERR(buf))
1156 return PTR_ERR(buf);
1157 }
1158
1159 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1160
1161 /* free the tmp buffer */
1162 if (cell->bit_offset || cell->nbits)
1163 kfree(buf);
1164
1165 if (rc)
1166 return rc;
1167
1168 return len;
1169}
1170EXPORT_SYMBOL_GPL(nvmem_cell_write);
1171
1172/**
1173 * nvmem_cell_read_u32() - Read a cell value as an u32
1174 *
1175 * @dev: Device that requests the nvmem cell.
1176 * @cell_id: Name of nvmem cell to read.
1177 * @val: pointer to output value.
1178 *
1179 * Return: 0 on success or negative errno.
1180 */
1181int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1182{
1183 struct nvmem_cell *cell;
1184 void *buf;
1185 size_t len;
1186
1187 cell = nvmem_cell_get(dev, cell_id);
1188 if (IS_ERR(cell))
1189 return PTR_ERR(cell);
1190
1191 buf = nvmem_cell_read(cell, &len);
1192 if (IS_ERR(buf)) {
1193 nvmem_cell_put(cell);
1194 return PTR_ERR(buf);
1195 }
1196 if (len != sizeof(*val)) {
1197 kfree(buf);
1198 nvmem_cell_put(cell);
1199 return -EINVAL;
1200 }
1201 memcpy(val, buf, sizeof(*val));
1202
1203 kfree(buf);
1204 nvmem_cell_put(cell);
1205 return 0;
1206}
1207EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1208
1209/**
1210 * nvmem_device_cell_read() - Read a given nvmem device and cell
1211 *
1212 * @nvmem: nvmem device to read from.
1213 * @info: nvmem cell info to be read.
1214 * @buf: buffer pointer which will be populated on successful read.
1215 *
1216 * Return: length of successful bytes read on success and negative
1217 * error code on error.
1218 */
1219ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1220 struct nvmem_cell_info *info, void *buf)
1221{
1222 struct nvmem_cell cell;
1223 int rc;
1224 ssize_t len;
1225
1226 if (!nvmem)
1227 return -EINVAL;
1228
1229 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1230 if (rc)
1231 return rc;
1232
1233 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1234 if (rc)
1235 return rc;
1236
1237 return len;
1238}
1239EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1240
1241/**
1242 * nvmem_device_cell_write() - Write cell to a given nvmem device
1243 *
1244 * @nvmem: nvmem device to be written to.
1245 * @info: nvmem cell info to be written.
1246 * @buf: buffer to be written to cell.
1247 *
1248 * Return: length of bytes written or negative error code on failure.
1249 * */
1250int nvmem_device_cell_write(struct nvmem_device *nvmem,
1251 struct nvmem_cell_info *info, void *buf)
1252{
1253 struct nvmem_cell cell;
1254 int rc;
1255
1256 if (!nvmem)
1257 return -EINVAL;
1258
1259 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1260 if (rc)
1261 return rc;
1262
1263 return nvmem_cell_write(&cell, buf, cell.bytes);
1264}
1265EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1266
1267/**
1268 * nvmem_device_read() - Read from a given nvmem device
1269 *
1270 * @nvmem: nvmem device to read from.
1271 * @offset: offset in nvmem device.
1272 * @bytes: number of bytes to read.
1273 * @buf: buffer pointer which will be populated on successful read.
1274 *
1275 * Return: length of successful bytes read on success and negative
1276 * error code on error.
1277 */
1278int nvmem_device_read(struct nvmem_device *nvmem,
1279 unsigned int offset,
1280 size_t bytes, void *buf)
1281{
1282 int rc;
1283
1284 if (!nvmem)
1285 return -EINVAL;
1286
1287 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1288
1289 if (rc)
1290 return rc;
1291
1292 return bytes;
1293}
1294EXPORT_SYMBOL_GPL(nvmem_device_read);
1295
1296/**
1297 * nvmem_device_write() - Write cell to a given nvmem device
1298 *
1299 * @nvmem: nvmem device to be written to.
1300 * @offset: offset in nvmem device.
1301 * @bytes: number of bytes to write.
1302 * @buf: buffer to be written.
1303 *
1304 * Return: length of bytes written or negative error code on failure.
1305 * */
1306int nvmem_device_write(struct nvmem_device *nvmem,
1307 unsigned int offset,
1308 size_t bytes, void *buf)
1309{
1310 int rc;
1311
1312 if (!nvmem)
1313 return -EINVAL;
1314
1315 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1316
1317 if (rc)
1318 return rc;
1319
1320
1321 return bytes;
1322}
1323EXPORT_SYMBOL_GPL(nvmem_device_write);
1324
1325static int __init nvmem_init(void)
1326{
1327 return bus_register(&nvmem_bus_type);
1328}
1329
1330static void __exit nvmem_exit(void)
1331{
1332 bus_unregister(&nvmem_bus_type);
1333}
1334
1335subsys_initcall(nvmem_init);
1336module_exit(nvmem_exit);
1337
1338MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1339MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1340MODULE_DESCRIPTION("nvmem Driver Core");
1341MODULE_LICENSE("GPL v2");