core.c 24.3 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
/*
 * nvmem framework core.
 *
 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/device.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>

struct nvmem_device {
	const char		*name;
	struct regmap		*regmap;
	struct module		*owner;
	struct device		dev;
	int			stride;
	int			word_size;
	int			ncells;
	int			id;
	int			users;
	size_t			size;
	bool			read_only;
};

struct nvmem_cell {
	const char		*name;
	int			offset;
	int			bytes;
	int			bit_offset;
	int			nbits;
	struct nvmem_device	*nvmem;
	struct list_head	node;
};

static DEFINE_MUTEX(nvmem_mutex);
static DEFINE_IDA(nvmem_ida);

static LIST_HEAD(nvmem_cells);
static DEFINE_MUTEX(nvmem_cells_mutex);

#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)

static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
				    struct bin_attribute *attr,
				    char *buf, loff_t pos, size_t count)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct nvmem_device *nvmem = to_nvmem_device(dev);
	int rc;

	/* Stop the user from reading */
70
	if (pos >= nvmem->size)
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
		return 0;

	if (pos + count > nvmem->size)
		count = nvmem->size - pos;

	count = round_down(count, nvmem->word_size);

	rc = regmap_raw_read(nvmem->regmap, pos, buf, count);

	if (IS_ERR_VALUE(rc))
		return rc;

	return count;
}

static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
				     struct bin_attribute *attr,
				     char *buf, loff_t pos, size_t count)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct nvmem_device *nvmem = to_nvmem_device(dev);
	int rc;

	/* Stop the user from writing */
95
	if (pos >= nvmem->size)
96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379
		return 0;

	if (pos + count > nvmem->size)
		count = nvmem->size - pos;

	count = round_down(count, nvmem->word_size);

	rc = regmap_raw_write(nvmem->regmap, pos, buf, count);

	if (IS_ERR_VALUE(rc))
		return rc;

	return count;
}

/* default read/write permissions */
static struct bin_attribute bin_attr_rw_nvmem = {
	.attr	= {
		.name	= "nvmem",
		.mode	= S_IWUSR | S_IRUGO,
	},
	.read	= bin_attr_nvmem_read,
	.write	= bin_attr_nvmem_write,
};

static struct bin_attribute *nvmem_bin_rw_attributes[] = {
	&bin_attr_rw_nvmem,
	NULL,
};

static const struct attribute_group nvmem_bin_rw_group = {
	.bin_attrs	= nvmem_bin_rw_attributes,
};

static const struct attribute_group *nvmem_rw_dev_groups[] = {
	&nvmem_bin_rw_group,
	NULL,
};

/* read only permission */
static struct bin_attribute bin_attr_ro_nvmem = {
	.attr	= {
		.name	= "nvmem",
		.mode	= S_IRUGO,
	},
	.read	= bin_attr_nvmem_read,
};

static struct bin_attribute *nvmem_bin_ro_attributes[] = {
	&bin_attr_ro_nvmem,
	NULL,
};

static const struct attribute_group nvmem_bin_ro_group = {
	.bin_attrs	= nvmem_bin_ro_attributes,
};

static const struct attribute_group *nvmem_ro_dev_groups[] = {
	&nvmem_bin_ro_group,
	NULL,
};

static void nvmem_release(struct device *dev)
{
	struct nvmem_device *nvmem = to_nvmem_device(dev);

	ida_simple_remove(&nvmem_ida, nvmem->id);
	kfree(nvmem);
}

static const struct device_type nvmem_provider_type = {
	.release	= nvmem_release,
};

static struct bus_type nvmem_bus_type = {
	.name		= "nvmem",
};

static int of_nvmem_match(struct device *dev, void *nvmem_np)
{
	return dev->of_node == nvmem_np;
}

static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
{
	struct device *d;

	if (!nvmem_np)
		return NULL;

	d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);

	if (!d)
		return NULL;

	return to_nvmem_device(d);
}

static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
{
	struct nvmem_cell *p;

	list_for_each_entry(p, &nvmem_cells, node)
		if (p && !strcmp(p->name, cell_id))
			return p;

	return NULL;
}

static void nvmem_cell_drop(struct nvmem_cell *cell)
{
	mutex_lock(&nvmem_cells_mutex);
	list_del(&cell->node);
	mutex_unlock(&nvmem_cells_mutex);
	kfree(cell);
}

static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
{
	struct nvmem_cell *cell;
	struct list_head *p, *n;

	list_for_each_safe(p, n, &nvmem_cells) {
		cell = list_entry(p, struct nvmem_cell, node);
		if (cell->nvmem == nvmem)
			nvmem_cell_drop(cell);
	}
}

static void nvmem_cell_add(struct nvmem_cell *cell)
{
	mutex_lock(&nvmem_cells_mutex);
	list_add_tail(&cell->node, &nvmem_cells);
	mutex_unlock(&nvmem_cells_mutex);
}

static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
				   const struct nvmem_cell_info *info,
				   struct nvmem_cell *cell)
{
	cell->nvmem = nvmem;
	cell->offset = info->offset;
	cell->bytes = info->bytes;
	cell->name = info->name;

	cell->bit_offset = info->bit_offset;
	cell->nbits = info->nbits;

	if (cell->nbits)
		cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
					   BITS_PER_BYTE);

	if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
		dev_err(&nvmem->dev,
			"cell %s unaligned to nvmem stride %d\n",
			cell->name, nvmem->stride);
		return -EINVAL;
	}

	return 0;
}

static int nvmem_add_cells(struct nvmem_device *nvmem,
			   const struct nvmem_config *cfg)
{
	struct nvmem_cell **cells;
	const struct nvmem_cell_info *info = cfg->cells;
	int i, rval;

	cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
	if (!cells)
		return -ENOMEM;

	for (i = 0; i < cfg->ncells; i++) {
		cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
		if (!cells[i]) {
			rval = -ENOMEM;
			goto err;
		}

		rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
		if (IS_ERR_VALUE(rval)) {
			kfree(cells[i]);
			goto err;
		}

		nvmem_cell_add(cells[i]);
	}

	nvmem->ncells = cfg->ncells;
	/* remove tmp array */
	kfree(cells);

	return 0;
err:
	while (--i)
		nvmem_cell_drop(cells[i]);

	return rval;
}

/**
 * nvmem_register() - Register a nvmem device for given nvmem_config.
 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 *
 * @config: nvmem device configuration with which nvmem device is created.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 * on success.
 */

struct nvmem_device *nvmem_register(const struct nvmem_config *config)
{
	struct nvmem_device *nvmem;
	struct device_node *np;
	struct regmap *rm;
	int rval;

	if (!config->dev)
		return ERR_PTR(-EINVAL);

	rm = dev_get_regmap(config->dev, NULL);
	if (!rm) {
		dev_err(config->dev, "Regmap not found\n");
		return ERR_PTR(-EINVAL);
	}

	nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
	if (!nvmem)
		return ERR_PTR(-ENOMEM);

	rval  = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
	if (rval < 0) {
		kfree(nvmem);
		return ERR_PTR(rval);
	}

	nvmem->id = rval;
	nvmem->regmap = rm;
	nvmem->owner = config->owner;
	nvmem->stride = regmap_get_reg_stride(rm);
	nvmem->word_size = regmap_get_val_bytes(rm);
	nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
	nvmem->dev.type = &nvmem_provider_type;
	nvmem->dev.bus = &nvmem_bus_type;
	nvmem->dev.parent = config->dev;
	np = config->dev->of_node;
	nvmem->dev.of_node = np;
	dev_set_name(&nvmem->dev, "%s%d",
		     config->name ? : "nvmem", config->id);

	nvmem->read_only = of_property_read_bool(np, "read-only") |
			   config->read_only;

	nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups :
					       nvmem_rw_dev_groups;

	device_initialize(&nvmem->dev);

	dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);

	rval = device_add(&nvmem->dev);
	if (rval) {
		ida_simple_remove(&nvmem_ida, nvmem->id);
		kfree(nvmem);
		return ERR_PTR(rval);
	}

	if (config->cells)
		nvmem_add_cells(nvmem, config);

	return nvmem;
}
EXPORT_SYMBOL_GPL(nvmem_register);

/**
 * nvmem_unregister() - Unregister previously registered nvmem device
 *
 * @nvmem: Pointer to previously registered nvmem device.
 *
 * Return: Will be an negative on error or a zero on success.
 */
int nvmem_unregister(struct nvmem_device *nvmem)
{
380 381 382
	mutex_lock(&nvmem_mutex);
	if (nvmem->users) {
		mutex_unlock(&nvmem_mutex);
383
		return -EBUSY;
384 385
	}
	mutex_unlock(&nvmem_mutex);
386 387 388 389 390 391 392 393

	nvmem_device_remove_all_cells(nvmem);
	device_del(&nvmem->dev);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmem_unregister);

394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447
static struct nvmem_device *__nvmem_device_get(struct device_node *np,
					       struct nvmem_cell **cellp,
					       const char *cell_id)
{
	struct nvmem_device *nvmem = NULL;

	mutex_lock(&nvmem_mutex);

	if (np) {
		nvmem = of_nvmem_find(np);
		if (!nvmem) {
			mutex_unlock(&nvmem_mutex);
			return ERR_PTR(-EPROBE_DEFER);
		}
	} else {
		struct nvmem_cell *cell = nvmem_find_cell(cell_id);

		if (cell) {
			nvmem = cell->nvmem;
			*cellp = cell;
		}

		if (!nvmem) {
			mutex_unlock(&nvmem_mutex);
			return ERR_PTR(-ENOENT);
		}
	}

	nvmem->users++;
	mutex_unlock(&nvmem_mutex);

	if (!try_module_get(nvmem->owner)) {
		dev_err(&nvmem->dev,
			"could not increase module refcount for cell %s\n",
			nvmem->name);

		mutex_lock(&nvmem_mutex);
		nvmem->users--;
		mutex_unlock(&nvmem_mutex);

		return ERR_PTR(-EINVAL);
	}

	return nvmem;
}

static void __nvmem_device_put(struct nvmem_device *nvmem)
{
	module_put(nvmem->owner);
	mutex_lock(&nvmem_mutex);
	nvmem->users--;
	mutex_unlock(&nvmem_mutex);
}

448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589
static int nvmem_match(struct device *dev, void *data)
{
	return !strcmp(dev_name(dev), data);
}

static struct nvmem_device *nvmem_find(const char *name)
{
	struct device *d;

	d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);

	if (!d)
		return NULL;

	return to_nvmem_device(d);
}

#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
/**
 * of_nvmem_device_get() - Get nvmem device from a given id
 *
 * @dev node: Device tree node that uses the nvmem device
 * @id: nvmem name from nvmem-names property.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 * on success.
 */
struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
{

	struct device_node *nvmem_np;
	int index;

	index = of_property_match_string(np, "nvmem-names", id);

	nvmem_np = of_parse_phandle(np, "nvmem", index);
	if (!nvmem_np)
		return ERR_PTR(-EINVAL);

	return __nvmem_device_get(nvmem_np, NULL, NULL);
}
EXPORT_SYMBOL_GPL(of_nvmem_device_get);
#endif

/**
 * nvmem_device_get() - Get nvmem device from a given id
 *
 * @dev : Device that uses the nvmem device
 * @id: nvmem name from nvmem-names property.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 * on success.
 */
struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
{
	if (dev->of_node) { /* try dt first */
		struct nvmem_device *nvmem;

		nvmem = of_nvmem_device_get(dev->of_node, dev_name);

		if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
			return nvmem;

	}

	return nvmem_find(dev_name);
}
EXPORT_SYMBOL_GPL(nvmem_device_get);

static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
{
	struct nvmem_device **nvmem = res;

	if (WARN_ON(!nvmem || !*nvmem))
		return 0;

	return *nvmem == data;
}

static void devm_nvmem_device_release(struct device *dev, void *res)
{
	nvmem_device_put(*(struct nvmem_device **)res);
}

/**
 * devm_nvmem_device_put() - put alredy got nvmem device
 *
 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
 * that needs to be released.
 */
void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
{
	int ret;

	ret = devres_release(dev, devm_nvmem_device_release,
			     devm_nvmem_device_match, nvmem);

	WARN_ON(ret);
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_put);

/**
 * nvmem_device_put() - put alredy got nvmem device
 *
 * @nvmem: pointer to nvmem device that needs to be released.
 */
void nvmem_device_put(struct nvmem_device *nvmem)
{
	__nvmem_device_put(nvmem);
}
EXPORT_SYMBOL_GPL(nvmem_device_put);

/**
 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
 *
 * @dev node: Device tree node that uses the nvmem cell
 * @id: nvmem name in nvmems property.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
 * on success.  The nvmem_cell will be freed by the automatically once the
 * device is freed.
 */
struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
{
	struct nvmem_device **ptr, *nvmem;

	ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	nvmem = nvmem_device_get(dev, id);
	if (!IS_ERR(nvmem)) {
		*ptr = nvmem;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return nvmem;
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_get);

590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950
static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
{
	struct nvmem_cell *cell = NULL;
	struct nvmem_device *nvmem;

	nvmem = __nvmem_device_get(NULL, &cell, cell_id);
	if (IS_ERR(nvmem))
		return ERR_CAST(nvmem);

	return cell;
}

#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
/**
 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
 *
 * @dev node: Device tree node that uses the nvmem cell
 * @id: nvmem cell name from nvmem-cell-names property.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * nvmem_cell_put().
 */
struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
					    const char *name)
{
	struct device_node *cell_np, *nvmem_np;
	struct nvmem_cell *cell;
	struct nvmem_device *nvmem;
	const __be32 *addr;
	int rval, len, index;

	index = of_property_match_string(np, "nvmem-cell-names", name);

	cell_np = of_parse_phandle(np, "nvmem-cells", index);
	if (!cell_np)
		return ERR_PTR(-EINVAL);

	nvmem_np = of_get_next_parent(cell_np);
	if (!nvmem_np)
		return ERR_PTR(-EINVAL);

	nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
	if (IS_ERR(nvmem))
		return ERR_CAST(nvmem);

	addr = of_get_property(cell_np, "reg", &len);
	if (!addr || (len < 2 * sizeof(u32))) {
		dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
			cell_np->full_name);
		rval  = -EINVAL;
		goto err_mem;
	}

	cell = kzalloc(sizeof(*cell), GFP_KERNEL);
	if (!cell) {
		rval = -ENOMEM;
		goto err_mem;
	}

	cell->nvmem = nvmem;
	cell->offset = be32_to_cpup(addr++);
	cell->bytes = be32_to_cpup(addr);
	cell->name = cell_np->name;

	addr = of_get_property(cell_np, "bits", &len);
	if (addr && len == (2 * sizeof(u32))) {
		cell->bit_offset = be32_to_cpup(addr++);
		cell->nbits = be32_to_cpup(addr);
	}

	if (cell->nbits)
		cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
					   BITS_PER_BYTE);

	if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
			dev_err(&nvmem->dev,
				"cell %s unaligned to nvmem stride %d\n",
				cell->name, nvmem->stride);
		rval  = -EINVAL;
		goto err_sanity;
	}

	nvmem_cell_add(cell);

	return cell;

err_sanity:
	kfree(cell);

err_mem:
	__nvmem_device_put(nvmem);

	return ERR_PTR(rval);
}
EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
#endif

/**
 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
 *
 * @dev node: Device tree node that uses the nvmem cell
 * @id: nvmem cell name to get.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * nvmem_cell_put().
 */
struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
{
	struct nvmem_cell *cell;

	if (dev->of_node) { /* try dt first */
		cell = of_nvmem_cell_get(dev->of_node, cell_id);
		if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
			return cell;
	}

	return nvmem_cell_get_from_list(cell_id);
}
EXPORT_SYMBOL_GPL(nvmem_cell_get);

static void devm_nvmem_cell_release(struct device *dev, void *res)
{
	nvmem_cell_put(*(struct nvmem_cell **)res);
}

/**
 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
 *
 * @dev node: Device tree node that uses the nvmem cell
 * @id: nvmem id in nvmem-names property.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * automatically once the device is freed.
 */
struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
{
	struct nvmem_cell **ptr, *cell;

	ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	cell = nvmem_cell_get(dev, id);
	if (!IS_ERR(cell)) {
		*ptr = cell;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return cell;
}
EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);

static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
{
	struct nvmem_cell **c = res;

	if (WARN_ON(!c || !*c))
		return 0;

	return *c == data;
}

/**
 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
 * from devm_nvmem_cell_get.
 *
 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
 */
void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
{
	int ret;

	ret = devres_release(dev, devm_nvmem_cell_release,
				devm_nvmem_cell_match, cell);

	WARN_ON(ret);
}
EXPORT_SYMBOL(devm_nvmem_cell_put);

/**
 * nvmem_cell_put() - Release previously allocated nvmem cell.
 *
 * @cell: Previously allocated nvmem cell by nvmem_cell_get()
 */
void nvmem_cell_put(struct nvmem_cell *cell)
{
	struct nvmem_device *nvmem = cell->nvmem;

	__nvmem_device_put(nvmem);
	nvmem_cell_drop(cell);
}
EXPORT_SYMBOL_GPL(nvmem_cell_put);

static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
						    void *buf)
{
	u8 *p, *b;
	int i, bit_offset = cell->bit_offset;

	p = b = buf;
	if (bit_offset) {
		/* First shift */
		*b++ >>= bit_offset;

		/* setup rest of the bytes if any */
		for (i = 1; i < cell->bytes; i++) {
			/* Get bits from next byte and shift them towards msb */
			*p |= *b << (BITS_PER_BYTE - bit_offset);

			p = b;
			*b++ >>= bit_offset;
		}

		/* result fits in less bytes */
		if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
			*p-- = 0;
	}
	/* clear msb bits if any leftover in the last byte */
	*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
}

static int __nvmem_cell_read(struct nvmem_device *nvmem,
		      struct nvmem_cell *cell,
		      void *buf, size_t *len)
{
	int rc;

	rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);

	if (IS_ERR_VALUE(rc))
		return rc;

	/* shift bits in-place */
	if (cell->bit_offset || cell->bit_offset)
		nvmem_shift_read_buffer_in_place(cell, buf);

	*len = cell->bytes;

	return 0;
}

/**
 * nvmem_cell_read() - Read a given nvmem cell
 *
 * @cell: nvmem cell to be read.
 * @len: pointer to length of cell which will be populated on successful read.
 *
 * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
 * The buffer should be freed by the consumer with a kfree().
 */
void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
{
	struct nvmem_device *nvmem = cell->nvmem;
	u8 *buf;
	int rc;

	if (!nvmem || !nvmem->regmap)
		return ERR_PTR(-EINVAL);

	buf = kzalloc(cell->bytes, GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	rc = __nvmem_cell_read(nvmem, cell, buf, len);
	if (IS_ERR_VALUE(rc)) {
		kfree(buf);
		return ERR_PTR(rc);
	}

	return buf;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read);

static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
						    u8 *_buf, int len)
{
	struct nvmem_device *nvmem = cell->nvmem;
	int i, rc, nbits, bit_offset = cell->bit_offset;
	u8 v, *p, *buf, *b, pbyte, pbits;

	nbits = cell->nbits;
	buf = kzalloc(cell->bytes, GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	memcpy(buf, _buf, len);
	p = b = buf;

	if (bit_offset) {
		pbyte = *b;
		*b <<= bit_offset;

		/* setup the first byte with lsb bits from nvmem */
		rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
		*b++ |= GENMASK(bit_offset - 1, 0) & v;

		/* setup rest of the byte if any */
		for (i = 1; i < cell->bytes; i++) {
			/* Get last byte bits and shift them towards lsb */
			pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
			pbyte = *b;
			p = b;
			*b <<= bit_offset;
			*b++ |= pbits;
		}
	}

	/* if it's not end on byte boundary */
	if ((nbits + bit_offset) % BITS_PER_BYTE) {
		/* setup the last byte with msb bits from nvmem */
		rc = regmap_raw_read(nvmem->regmap,
				    cell->offset + cell->bytes - 1, &v, 1);
		*p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;

	}

	return buf;
}

/**
 * nvmem_cell_write() - Write to a given nvmem cell
 *
 * @cell: nvmem cell to be written.
 * @buf: Buffer to be written.
 * @len: length of buffer to be written to nvmem cell.
 *
 * Return: length of bytes written or negative on failure.
 */
int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
{
	struct nvmem_device *nvmem = cell->nvmem;
	int rc;

	if (!nvmem || !nvmem->regmap || nvmem->read_only ||
	    (cell->bit_offset == 0 && len != cell->bytes))
		return -EINVAL;

	if (cell->bit_offset || cell->nbits) {
		buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
		if (IS_ERR(buf))
			return PTR_ERR(buf);
	}

	rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);

	/* free the tmp buffer */
	if (cell->bit_offset)
		kfree(buf);

	if (IS_ERR_VALUE(rc))
		return rc;

	return len;
}
EXPORT_SYMBOL_GPL(nvmem_cell_write);

951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066
/**
 * nvmem_device_cell_read() - Read a given nvmem device and cell
 *
 * @nvmem: nvmem device to read from.
 * @info: nvmem cell info to be read.
 * @buf: buffer pointer which will be populated on successful read.
 *
 * Return: length of successful bytes read on success and negative
 * error code on error.
 */
ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
			   struct nvmem_cell_info *info, void *buf)
{
	struct nvmem_cell cell;
	int rc;
	ssize_t len;

	if (!nvmem || !nvmem->regmap)
		return -EINVAL;

	rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
	if (IS_ERR_VALUE(rc))
		return rc;

	rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
	if (IS_ERR_VALUE(rc))
		return rc;

	return len;
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_read);

/**
 * nvmem_device_cell_write() - Write cell to a given nvmem device
 *
 * @nvmem: nvmem device to be written to.
 * @info: nvmem cell info to be written
 * @buf: buffer to be written to cell.
 *
 * Return: length of bytes written or negative error code on failure.
 * */
int nvmem_device_cell_write(struct nvmem_device *nvmem,
			    struct nvmem_cell_info *info, void *buf)
{
	struct nvmem_cell cell;
	int rc;

	if (!nvmem || !nvmem->regmap)
		return -EINVAL;

	rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
	if (IS_ERR_VALUE(rc))
		return rc;

	return nvmem_cell_write(&cell, buf, cell.bytes);
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_write);

/**
 * nvmem_device_read() - Read from a given nvmem device
 *
 * @nvmem: nvmem device to read from.
 * @offset: offset in nvmem device.
 * @bytes: number of bytes to read.
 * @buf: buffer pointer which will be populated on successful read.
 *
 * Return: length of successful bytes read on success and negative
 * error code on error.
 */
int nvmem_device_read(struct nvmem_device *nvmem,
		      unsigned int offset,
		      size_t bytes, void *buf)
{
	int rc;

	if (!nvmem || !nvmem->regmap)
		return -EINVAL;

	rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);

	if (IS_ERR_VALUE(rc))
		return rc;

	return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_read);

/**
 * nvmem_device_write() - Write cell to a given nvmem device
 *
 * @nvmem: nvmem device to be written to.
 * @offset: offset in nvmem device.
 * @bytes: number of bytes to write.
 * @buf: buffer to be written.
 *
 * Return: length of bytes written or negative error code on failure.
 * */
int nvmem_device_write(struct nvmem_device *nvmem,
		       unsigned int offset,
		       size_t bytes, void *buf)
{
	int rc;

	if (!nvmem || !nvmem->regmap)
		return -EINVAL;

	rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);

	if (IS_ERR_VALUE(rc))
		return rc;


	return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_write);

1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
static int __init nvmem_init(void)
{
	return bus_register(&nvmem_bus_type);
}

static void __exit nvmem_exit(void)
{
	bus_unregister(&nvmem_bus_type);
}

subsys_initcall(nvmem_init);
module_exit(nvmem_exit);

MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
MODULE_DESCRIPTION("nvmem Driver Core");
MODULE_LICENSE("GPL v2");