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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 0;
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 list_for_each_entry(p, &nvmem_cells, node)
291 if (p && !strcmp(p->name, cell_id))
292 return p;
293
294 return NULL;
295}
296
297static void nvmem_cell_drop(struct nvmem_cell *cell)
298{
299 mutex_lock(&nvmem_cells_mutex);
300 list_del(&cell->node);
301 mutex_unlock(&nvmem_cells_mutex);
302 kfree(cell);
303}
304
305static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
306{
307 struct nvmem_cell *cell;
308 struct list_head *p, *n;
309
310 list_for_each_safe(p, n, &nvmem_cells) {
311 cell = list_entry(p, struct nvmem_cell, node);
312 if (cell->nvmem == nvmem)
313 nvmem_cell_drop(cell);
314 }
315}
316
317static void nvmem_cell_add(struct nvmem_cell *cell)
318{
319 mutex_lock(&nvmem_cells_mutex);
320 list_add_tail(&cell->node, &nvmem_cells);
321 mutex_unlock(&nvmem_cells_mutex);
322}
323
324static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
325 const struct nvmem_cell_info *info,
326 struct nvmem_cell *cell)
327{
328 cell->nvmem = nvmem;
329 cell->offset = info->offset;
330 cell->bytes = info->bytes;
331 cell->name = info->name;
332
333 cell->bit_offset = info->bit_offset;
334 cell->nbits = info->nbits;
335
336 if (cell->nbits)
337 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
338 BITS_PER_BYTE);
339
340 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
341 dev_err(&nvmem->dev,
342 "cell %s unaligned to nvmem stride %d\n",
343 cell->name, nvmem->stride);
344 return -EINVAL;
345 }
346
347 return 0;
348}
349
350static int nvmem_add_cells(struct nvmem_device *nvmem,
351 const struct nvmem_config *cfg)
352{
353 struct nvmem_cell **cells;
354 const struct nvmem_cell_info *info = cfg->cells;
355 int i, rval;
356
357 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
358 if (!cells)
359 return -ENOMEM;
360
361 for (i = 0; i < cfg->ncells; i++) {
362 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
363 if (!cells[i]) {
364 rval = -ENOMEM;
365 goto err;
366 }
367
368 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
369 if (rval) {
370 kfree(cells[i]);
371 goto err;
372 }
373
374 nvmem_cell_add(cells[i]);
375 }
376
377 nvmem->ncells = cfg->ncells;
378 /* remove tmp array */
379 kfree(cells);
380
381 return 0;
382err:
383 while (i--)
384 nvmem_cell_drop(cells[i]);
385
386 kfree(cells);
387
388 return rval;
389}
390
391/*
392 * nvmem_setup_compat() - Create an additional binary entry in
393 * drivers sys directory, to be backwards compatible with the older
394 * drivers/misc/eeprom drivers.
395 */
396static int nvmem_setup_compat(struct nvmem_device *nvmem,
397 const struct nvmem_config *config)
398{
399 int rval;
400
401 if (!config->base_dev)
402 return -EINVAL;
403
404 if (nvmem->read_only)
405 nvmem->eeprom = bin_attr_ro_root_nvmem;
406 else
407 nvmem->eeprom = bin_attr_rw_root_nvmem;
408 nvmem->eeprom.attr.name = "eeprom";
409 nvmem->eeprom.size = nvmem->size;
410#ifdef CONFIG_DEBUG_LOCK_ALLOC
411 nvmem->eeprom.attr.key = &eeprom_lock_key;
412#endif
413 nvmem->eeprom.private = &nvmem->dev;
414 nvmem->base_dev = config->base_dev;
415
416 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
417 if (rval) {
418 dev_err(&nvmem->dev,
419 "Failed to create eeprom binary file %d\n", rval);
420 return rval;
421 }
422
423 nvmem->flags |= FLAG_COMPAT;
424
425 return 0;
426}
427
428/**
429 * nvmem_register() - Register a nvmem device for given nvmem_config.
430 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
431 *
432 * @config: nvmem device configuration with which nvmem device is created.
433 *
434 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
435 * on success.
436 */
437
438struct nvmem_device *nvmem_register(const struct nvmem_config *config)
439{
440 struct nvmem_device *nvmem;
441 struct device_node *np;
442 int rval;
443
444 if (!config->dev)
445 return ERR_PTR(-EINVAL);
446
447 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
448 if (!nvmem)
449 return ERR_PTR(-ENOMEM);
450
451 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
452 if (rval < 0) {
453 kfree(nvmem);
454 return ERR_PTR(rval);
455 }
456
457 nvmem->id = rval;
458 nvmem->owner = config->owner;
459 nvmem->stride = config->stride;
460 nvmem->word_size = config->word_size;
461 nvmem->size = config->size;
462 nvmem->dev.type = &nvmem_provider_type;
463 nvmem->dev.bus = &nvmem_bus_type;
464 nvmem->dev.parent = config->dev;
465 nvmem->priv = config->priv;
466 nvmem->reg_read = config->reg_read;
467 nvmem->reg_write = config->reg_write;
468 np = config->dev->of_node;
469 nvmem->dev.of_node = np;
470 dev_set_name(&nvmem->dev, "%s%d",
471 config->name ? : "nvmem", config->id);
472
473 nvmem->read_only = of_property_read_bool(np, "read-only") |
474 config->read_only;
475
476 if (config->root_only)
477 nvmem->dev.groups = nvmem->read_only ?
478 nvmem_ro_root_dev_groups :
479 nvmem_rw_root_dev_groups;
480 else
481 nvmem->dev.groups = nvmem->read_only ?
482 nvmem_ro_dev_groups :
483 nvmem_rw_dev_groups;
484
485 device_initialize(&nvmem->dev);
486
487 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
488
489 rval = device_add(&nvmem->dev);
490 if (rval)
491 goto out;
492
493 if (config->compat) {
494 rval = nvmem_setup_compat(nvmem, config);
495 if (rval)
496 goto out;
497 }
498
499 if (config->cells)
500 nvmem_add_cells(nvmem, config);
501
502 return nvmem;
503out:
504 ida_simple_remove(&nvmem_ida, nvmem->id);
505 kfree(nvmem);
506 return ERR_PTR(rval);
507}
508EXPORT_SYMBOL_GPL(nvmem_register);
509
510/**
511 * nvmem_unregister() - Unregister previously registered nvmem device
512 *
513 * @nvmem: Pointer to previously registered nvmem device.
514 *
515 * Return: Will be an negative on error or a zero on success.
516 */
517int nvmem_unregister(struct nvmem_device *nvmem)
518{
519 mutex_lock(&nvmem_mutex);
520 if (nvmem->users) {
521 mutex_unlock(&nvmem_mutex);
522 return -EBUSY;
523 }
524 mutex_unlock(&nvmem_mutex);
525
526 if (nvmem->flags & FLAG_COMPAT)
527 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
528
529 nvmem_device_remove_all_cells(nvmem);
530 device_del(&nvmem->dev);
531
532 return 0;
533}
534EXPORT_SYMBOL_GPL(nvmem_unregister);
535
536static struct nvmem_device *__nvmem_device_get(struct device_node *np,
537 struct nvmem_cell **cellp,
538 const char *cell_id)
539{
540 struct nvmem_device *nvmem = NULL;
541
542 mutex_lock(&nvmem_mutex);
543
544 if (np) {
545 nvmem = of_nvmem_find(np);
546 if (!nvmem) {
547 mutex_unlock(&nvmem_mutex);
548 return ERR_PTR(-EPROBE_DEFER);
549 }
550 } else {
551 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
552
553 if (cell) {
554 nvmem = cell->nvmem;
555 *cellp = cell;
556 }
557
558 if (!nvmem) {
559 mutex_unlock(&nvmem_mutex);
560 return ERR_PTR(-ENOENT);
561 }
562 }
563
564 nvmem->users++;
565 mutex_unlock(&nvmem_mutex);
566
567 if (!try_module_get(nvmem->owner)) {
568 dev_err(&nvmem->dev,
569 "could not increase module refcount for cell %s\n",
570 nvmem->name);
571
572 mutex_lock(&nvmem_mutex);
573 nvmem->users--;
574 mutex_unlock(&nvmem_mutex);
575
576 return ERR_PTR(-EINVAL);
577 }
578
579 return nvmem;
580}
581
582static void __nvmem_device_put(struct nvmem_device *nvmem)
583{
584 module_put(nvmem->owner);
585 mutex_lock(&nvmem_mutex);
586 nvmem->users--;
587 mutex_unlock(&nvmem_mutex);
588}
589
590static int nvmem_match(struct device *dev, void *data)
591{
592 return !strcmp(dev_name(dev), data);
593}
594
595static struct nvmem_device *nvmem_find(const char *name)
596{
597 struct device *d;
598
599 d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
600
601 if (!d)
602 return NULL;
603
604 return to_nvmem_device(d);
605}
606
607#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
608/**
609 * of_nvmem_device_get() - Get nvmem device from a given id
610 *
611 * @dev node: Device tree node that uses the nvmem device
612 * @id: nvmem name from nvmem-names property.
613 *
614 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
615 * on success.
616 */
617struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
618{
619
620 struct device_node *nvmem_np;
621 int index;
622
623 index = of_property_match_string(np, "nvmem-names", id);
624
625 nvmem_np = of_parse_phandle(np, "nvmem", index);
626 if (!nvmem_np)
627 return ERR_PTR(-EINVAL);
628
629 return __nvmem_device_get(nvmem_np, NULL, NULL);
630}
631EXPORT_SYMBOL_GPL(of_nvmem_device_get);
632#endif
633
634/**
635 * nvmem_device_get() - Get nvmem device from a given id
636 *
637 * @dev : Device that uses the nvmem device
638 * @id: nvmem name from nvmem-names property.
639 *
640 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
641 * on success.
642 */
643struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
644{
645 if (dev->of_node) { /* try dt first */
646 struct nvmem_device *nvmem;
647
648 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
649
650 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
651 return nvmem;
652
653 }
654
655 return nvmem_find(dev_name);
656}
657EXPORT_SYMBOL_GPL(nvmem_device_get);
658
659static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
660{
661 struct nvmem_device **nvmem = res;
662
663 if (WARN_ON(!nvmem || !*nvmem))
664 return 0;
665
666 return *nvmem == data;
667}
668
669static void devm_nvmem_device_release(struct device *dev, void *res)
670{
671 nvmem_device_put(*(struct nvmem_device **)res);
672}
673
674/**
675 * devm_nvmem_device_put() - put alredy got nvmem device
676 *
677 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
678 * that needs to be released.
679 */
680void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
681{
682 int ret;
683
684 ret = devres_release(dev, devm_nvmem_device_release,
685 devm_nvmem_device_match, nvmem);
686
687 WARN_ON(ret);
688}
689EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
690
691/**
692 * nvmem_device_put() - put alredy got nvmem device
693 *
694 * @nvmem: pointer to nvmem device that needs to be released.
695 */
696void nvmem_device_put(struct nvmem_device *nvmem)
697{
698 __nvmem_device_put(nvmem);
699}
700EXPORT_SYMBOL_GPL(nvmem_device_put);
701
702/**
703 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
704 *
705 * @dev node: Device tree node that uses the nvmem cell
706 * @id: nvmem name in nvmems property.
707 *
708 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
709 * on success. The nvmem_cell will be freed by the automatically once the
710 * device is freed.
711 */
712struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
713{
714 struct nvmem_device **ptr, *nvmem;
715
716 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
717 if (!ptr)
718 return ERR_PTR(-ENOMEM);
719
720 nvmem = nvmem_device_get(dev, id);
721 if (!IS_ERR(nvmem)) {
722 *ptr = nvmem;
723 devres_add(dev, ptr);
724 } else {
725 devres_free(ptr);
726 }
727
728 return nvmem;
729}
730EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
731
732static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
733{
734 struct nvmem_cell *cell = NULL;
735 struct nvmem_device *nvmem;
736
737 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
738 if (IS_ERR(nvmem))
739 return ERR_CAST(nvmem);
740
741 return cell;
742}
743
744#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
745/**
746 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
747 *
748 * @dev node: Device tree node that uses the nvmem cell
749 * @id: nvmem cell name from nvmem-cell-names property.
750 *
751 * Return: Will be an ERR_PTR() on error or a valid pointer
752 * to a struct nvmem_cell. The nvmem_cell will be freed by the
753 * nvmem_cell_put().
754 */
755struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
756 const char *name)
757{
758 struct device_node *cell_np, *nvmem_np;
759 struct nvmem_cell *cell;
760 struct nvmem_device *nvmem;
761 const __be32 *addr;
762 int rval, len, index;
763
764 index = of_property_match_string(np, "nvmem-cell-names", name);
765
766 cell_np = of_parse_phandle(np, "nvmem-cells", index);
767 if (!cell_np)
768 return ERR_PTR(-EINVAL);
769
770 nvmem_np = of_get_next_parent(cell_np);
771 if (!nvmem_np)
772 return ERR_PTR(-EINVAL);
773
774 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
775 if (IS_ERR(nvmem))
776 return ERR_CAST(nvmem);
777
778 addr = of_get_property(cell_np, "reg", &len);
779 if (!addr || (len < 2 * sizeof(u32))) {
780 dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
781 cell_np->full_name);
782 rval = -EINVAL;
783 goto err_mem;
784 }
785
786 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
787 if (!cell) {
788 rval = -ENOMEM;
789 goto err_mem;
790 }
791
792 cell->nvmem = nvmem;
793 cell->offset = be32_to_cpup(addr++);
794 cell->bytes = be32_to_cpup(addr);
795 cell->name = cell_np->name;
796
797 addr = of_get_property(cell_np, "bits", &len);
798 if (addr && len == (2 * sizeof(u32))) {
799 cell->bit_offset = be32_to_cpup(addr++);
800 cell->nbits = be32_to_cpup(addr);
801 }
802
803 if (cell->nbits)
804 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
805 BITS_PER_BYTE);
806
807 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
808 dev_err(&nvmem->dev,
809 "cell %s unaligned to nvmem stride %d\n",
810 cell->name, nvmem->stride);
811 rval = -EINVAL;
812 goto err_sanity;
813 }
814
815 nvmem_cell_add(cell);
816
817 return cell;
818
819err_sanity:
820 kfree(cell);
821
822err_mem:
823 __nvmem_device_put(nvmem);
824
825 return ERR_PTR(rval);
826}
827EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
828#endif
829
830/**
831 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
832 *
833 * @dev node: Device tree node that uses the nvmem cell
834 * @id: nvmem cell name to get.
835 *
836 * Return: Will be an ERR_PTR() on error or a valid pointer
837 * to a struct nvmem_cell. The nvmem_cell will be freed by the
838 * nvmem_cell_put().
839 */
840struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
841{
842 struct nvmem_cell *cell;
843
844 if (dev->of_node) { /* try dt first */
845 cell = of_nvmem_cell_get(dev->of_node, cell_id);
846 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
847 return cell;
848 }
849
850 return nvmem_cell_get_from_list(cell_id);
851}
852EXPORT_SYMBOL_GPL(nvmem_cell_get);
853
854static void devm_nvmem_cell_release(struct device *dev, void *res)
855{
856 nvmem_cell_put(*(struct nvmem_cell **)res);
857}
858
859/**
860 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
861 *
862 * @dev node: Device tree node that uses the nvmem cell
863 * @id: nvmem id in nvmem-names property.
864 *
865 * Return: Will be an ERR_PTR() on error or a valid pointer
866 * to a struct nvmem_cell. The nvmem_cell will be freed by the
867 * automatically once the device is freed.
868 */
869struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
870{
871 struct nvmem_cell **ptr, *cell;
872
873 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
874 if (!ptr)
875 return ERR_PTR(-ENOMEM);
876
877 cell = nvmem_cell_get(dev, id);
878 if (!IS_ERR(cell)) {
879 *ptr = cell;
880 devres_add(dev, ptr);
881 } else {
882 devres_free(ptr);
883 }
884
885 return cell;
886}
887EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
888
889static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
890{
891 struct nvmem_cell **c = res;
892
893 if (WARN_ON(!c || !*c))
894 return 0;
895
896 return *c == data;
897}
898
899/**
900 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
901 * from devm_nvmem_cell_get.
902 *
903 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
904 */
905void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
906{
907 int ret;
908
909 ret = devres_release(dev, devm_nvmem_cell_release,
910 devm_nvmem_cell_match, cell);
911
912 WARN_ON(ret);
913}
914EXPORT_SYMBOL(devm_nvmem_cell_put);
915
916/**
917 * nvmem_cell_put() - Release previously allocated nvmem cell.
918 *
919 * @cell: Previously allocated nvmem cell by nvmem_cell_get()
920 */
921void nvmem_cell_put(struct nvmem_cell *cell)
922{
923 struct nvmem_device *nvmem = cell->nvmem;
924
925 __nvmem_device_put(nvmem);
926 nvmem_cell_drop(cell);
927}
928EXPORT_SYMBOL_GPL(nvmem_cell_put);
929
930static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
931 void *buf)
932{
933 u8 *p, *b;
934 int i, bit_offset = cell->bit_offset;
935
936 p = b = buf;
937 if (bit_offset) {
938 /* First shift */
939 *b++ >>= bit_offset;
940
941 /* setup rest of the bytes if any */
942 for (i = 1; i < cell->bytes; i++) {
943 /* Get bits from next byte and shift them towards msb */
944 *p |= *b << (BITS_PER_BYTE - bit_offset);
945
946 p = b;
947 *b++ >>= bit_offset;
948 }
949
950 /* result fits in less bytes */
951 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
952 *p-- = 0;
953 }
954 /* clear msb bits if any leftover in the last byte */
955 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
956}
957
958static int __nvmem_cell_read(struct nvmem_device *nvmem,
959 struct nvmem_cell *cell,
960 void *buf, size_t *len)
961{
962 int rc;
963
964 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
965
966 if (rc)
967 return rc;
968
969 /* shift bits in-place */
970 if (cell->bit_offset || cell->nbits)
971 nvmem_shift_read_buffer_in_place(cell, buf);
972
973 *len = cell->bytes;
974
975 return 0;
976}
977
978/**
979 * nvmem_cell_read() - Read a given nvmem cell
980 *
981 * @cell: nvmem cell to be read.
982 * @len: pointer to length of cell which will be populated on successful read.
983 *
984 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
985 * buffer should be freed by the consumer with a kfree().
986 */
987void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
988{
989 struct nvmem_device *nvmem = cell->nvmem;
990 u8 *buf;
991 int rc;
992
993 if (!nvmem)
994 return ERR_PTR(-EINVAL);
995
996 buf = kzalloc(cell->bytes, GFP_KERNEL);
997 if (!buf)
998 return ERR_PTR(-ENOMEM);
999
1000 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1001 if (rc) {
1002 kfree(buf);
1003 return ERR_PTR(rc);
1004 }
1005
1006 return buf;
1007}
1008EXPORT_SYMBOL_GPL(nvmem_cell_read);
1009
1010static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1011 u8 *_buf, int len)
1012{
1013 struct nvmem_device *nvmem = cell->nvmem;
1014 int i, rc, nbits, bit_offset = cell->bit_offset;
1015 u8 v, *p, *buf, *b, pbyte, pbits;
1016
1017 nbits = cell->nbits;
1018 buf = kzalloc(cell->bytes, GFP_KERNEL);
1019 if (!buf)
1020 return ERR_PTR(-ENOMEM);
1021
1022 memcpy(buf, _buf, len);
1023 p = b = buf;
1024
1025 if (bit_offset) {
1026 pbyte = *b;
1027 *b <<= bit_offset;
1028
1029 /* setup the first byte with lsb bits from nvmem */
1030 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1031 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1032
1033 /* setup rest of the byte if any */
1034 for (i = 1; i < cell->bytes; i++) {
1035 /* Get last byte bits and shift them towards lsb */
1036 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1037 pbyte = *b;
1038 p = b;
1039 *b <<= bit_offset;
1040 *b++ |= pbits;
1041 }
1042 }
1043
1044 /* if it's not end on byte boundary */
1045 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1046 /* setup the last byte with msb bits from nvmem */
1047 rc = nvmem_reg_read(nvmem,
1048 cell->offset + cell->bytes - 1, &v, 1);
1049 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1050
1051 }
1052
1053 return buf;
1054}
1055
1056/**
1057 * nvmem_cell_write() - Write to a given nvmem cell
1058 *
1059 * @cell: nvmem cell to be written.
1060 * @buf: Buffer to be written.
1061 * @len: length of buffer to be written to nvmem cell.
1062 *
1063 * Return: length of bytes written or negative on failure.
1064 */
1065int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1066{
1067 struct nvmem_device *nvmem = cell->nvmem;
1068 int rc;
1069
1070 if (!nvmem || nvmem->read_only ||
1071 (cell->bit_offset == 0 && len != cell->bytes))
1072 return -EINVAL;
1073
1074 if (cell->bit_offset || cell->nbits) {
1075 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1076 if (IS_ERR(buf))
1077 return PTR_ERR(buf);
1078 }
1079
1080 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1081
1082 /* free the tmp buffer */
1083 if (cell->bit_offset || cell->nbits)
1084 kfree(buf);
1085
1086 if (rc)
1087 return rc;
1088
1089 return len;
1090}
1091EXPORT_SYMBOL_GPL(nvmem_cell_write);
1092
1093/**
1094 * nvmem_device_cell_read() - Read a given nvmem device and cell
1095 *
1096 * @nvmem: nvmem device to read from.
1097 * @info: nvmem cell info to be read.
1098 * @buf: buffer pointer which will be populated on successful read.
1099 *
1100 * Return: length of successful bytes read on success and negative
1101 * error code on error.
1102 */
1103ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1104 struct nvmem_cell_info *info, void *buf)
1105{
1106 struct nvmem_cell cell;
1107 int rc;
1108 ssize_t len;
1109
1110 if (!nvmem)
1111 return -EINVAL;
1112
1113 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1114 if (rc)
1115 return rc;
1116
1117 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1118 if (rc)
1119 return rc;
1120
1121 return len;
1122}
1123EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1124
1125/**
1126 * nvmem_device_cell_write() - Write cell to a given nvmem device
1127 *
1128 * @nvmem: nvmem device to be written to.
1129 * @info: nvmem cell info to be written
1130 * @buf: buffer to be written to cell.
1131 *
1132 * Return: length of bytes written or negative error code on failure.
1133 * */
1134int nvmem_device_cell_write(struct nvmem_device *nvmem,
1135 struct nvmem_cell_info *info, void *buf)
1136{
1137 struct nvmem_cell cell;
1138 int rc;
1139
1140 if (!nvmem)
1141 return -EINVAL;
1142
1143 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1144 if (rc)
1145 return rc;
1146
1147 return nvmem_cell_write(&cell, buf, cell.bytes);
1148}
1149EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1150
1151/**
1152 * nvmem_device_read() - Read from a given nvmem device
1153 *
1154 * @nvmem: nvmem device to read from.
1155 * @offset: offset in nvmem device.
1156 * @bytes: number of bytes to read.
1157 * @buf: buffer pointer which will be populated on successful read.
1158 *
1159 * Return: length of successful bytes read on success and negative
1160 * error code on error.
1161 */
1162int nvmem_device_read(struct nvmem_device *nvmem,
1163 unsigned int offset,
1164 size_t bytes, void *buf)
1165{
1166 int rc;
1167
1168 if (!nvmem)
1169 return -EINVAL;
1170
1171 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1172
1173 if (rc)
1174 return rc;
1175
1176 return bytes;
1177}
1178EXPORT_SYMBOL_GPL(nvmem_device_read);
1179
1180/**
1181 * nvmem_device_write() - Write cell to a given nvmem device
1182 *
1183 * @nvmem: nvmem device to be written to.
1184 * @offset: offset in nvmem device.
1185 * @bytes: number of bytes to write.
1186 * @buf: buffer to be written.
1187 *
1188 * Return: length of bytes written or negative error code on failure.
1189 * */
1190int nvmem_device_write(struct nvmem_device *nvmem,
1191 unsigned int offset,
1192 size_t bytes, void *buf)
1193{
1194 int rc;
1195
1196 if (!nvmem)
1197 return -EINVAL;
1198
1199 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1200
1201 if (rc)
1202 return rc;
1203
1204
1205 return bytes;
1206}
1207EXPORT_SYMBOL_GPL(nvmem_device_write);
1208
1209static int __init nvmem_init(void)
1210{
1211 return bus_register(&nvmem_bus_type);
1212}
1213
1214static void __exit nvmem_exit(void)
1215{
1216 bus_unregister(&nvmem_bus_type);
1217}
1218
1219subsys_initcall(nvmem_init);
1220module_exit(nvmem_exit);
1221
1222MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1223MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1224MODULE_DESCRIPTION("nvmem Driver Core");
1225MODULE_LICENSE("GPL v2");