[mirror_ubuntu-zesty-kernel.git] / arch / mips / bcm47xx / nvram.c

/*
 * BCM947xx nvram variable access
 *
 * Copyright (C) 2005 Broadcom Corporation
 * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
 * Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
 *
 * This program is free software; you can redistribute	it and/or modify it
 * under  the terms of	the GNU General	 Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */

#include <linux/io.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mtd/mtd.h>
#include <linux/bcm47xx_nvram.h>

#define NVRAM_MAGIC			0x48534C46	/* 'FLSH' */
#define NVRAM_SPACE			0x8000
#define NVRAM_MAX_GPIO_ENTRIES		32
#define NVRAM_MAX_GPIO_VALUE_LEN	30

#define FLASH_MIN		0x00020000	/* Minimum flash size */

struct nvram_header {
	u32 magic;
	u32 len;
	u32 crc_ver_init;	/* 0:7 crc, 8:15 ver, 16:31 sdram_init */
	u32 config_refresh;	/* 0:15 sdram_config, 16:31 sdram_refresh */
	u32 config_ncdl;	/* ncdl values for memc */
};

static char nvram_buf[NVRAM_SPACE];
static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};

static u32 find_nvram_size(void __iomem *end)
{
	struct nvram_header __iomem *header;
	int i;

	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
		header = (struct nvram_header *)(end - nvram_sizes[i]);
		if (header->magic == NVRAM_MAGIC)
			return nvram_sizes[i];
	}

	return 0;
}

/* Probe for NVRAM header */
static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
{
	struct nvram_header __iomem *header;
	int i;
	u32 off;
	u32 *src, *dst;
	u32 size;

	if (nvram_buf[0]) {
		pr_warn("nvram already initialized\n");
		return -EEXIST;
	}

	/* TODO: when nvram is on nand flash check for bad blocks first. */
	off = FLASH_MIN;
	while (off <= lim) {
		/* Windowed flash access */
		size = find_nvram_size(iobase + off);
		if (size) {
			header = (struct nvram_header *)(iobase + off - size);
			goto found;
		}
		off <<= 1;
	}

	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
	header = (struct nvram_header *)(iobase + 4096);
	if (header->magic == NVRAM_MAGIC) {
		size = NVRAM_SPACE;
		goto found;
	}

	header = (struct nvram_header *)(iobase + 1024);
	if (header->magic == NVRAM_MAGIC) {
		size = NVRAM_SPACE;
		goto found;
	}

	pr_err("no nvram found\n");
	return -ENXIO;

found:
	if (header->len > size)
		pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
	if (header->len > NVRAM_SPACE)
		pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
		       header->len, NVRAM_SPACE);

	src = (u32 *)header;
	dst = (u32 *)nvram_buf;
	for (i = 0; i < sizeof(struct nvram_header); i += 4)
		*dst++ = __raw_readl(src++);
	for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
		*dst++ = readl(src++);

	return 0;
}

/*
 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
 * subsystem to access flash. We can't even use platform device / driver to
 * store memory offset.
 * To handle this we provide following symbol. It's supposed to be called as
 * soon as we get info about flash device, before any NVRAM entry is needed.
 */
int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
{
	void __iomem *iobase;
	int err;

	iobase = ioremap_nocache(base, lim);
	if (!iobase)
		return -ENOMEM;

	err = nvram_find_and_copy(iobase, lim);

	iounmap(iobase);

	return err;
}

static int nvram_init(void)
{
#ifdef CONFIG_MTD
	struct mtd_info *mtd;
	struct nvram_header header;
	size_t bytes_read;
	int err, i;

	mtd = get_mtd_device_nm("nvram");
	if (IS_ERR(mtd))
		return -ENODEV;

	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
		loff_t from = mtd->size - nvram_sizes[i];

		if (from < 0)
			continue;

		err = mtd_read(mtd, from, sizeof(header), &bytes_read,
			       (uint8_t *)&header);
		if (!err && header.magic == NVRAM_MAGIC) {
			u8 *dst = (uint8_t *)nvram_buf;
			size_t len = header.len;

			if (header.len > NVRAM_SPACE) {
				pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
				       header.len, NVRAM_SPACE);
				len = NVRAM_SPACE;
			}

			err = mtd_read(mtd, from, len, &bytes_read, dst);
			if (err)
				return err;

			return 0;
		}
	}
#endif

	return -ENXIO;
}

int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
{
	char *var, *value, *end, *eq;
	int data_left, err;

	if (!name)
		return -EINVAL;

	if (!nvram_buf[0]) {
		err = nvram_init();
		if (err)
			return err;
	}

	/* Look for name=value and return value */
	var = &nvram_buf[sizeof(struct nvram_header)];
	end = nvram_buf + sizeof(nvram_buf) - 2;
	end[0] = '\0';
	end[1] = '\0';
	for (; *var; var = value + strlen(value) + 1) {
		data_left = end - var;

		eq = strnchr(var, data_left, '=');
		if (!eq)
			break;
		value = eq + 1;
		if (eq - var == strlen(name) &&
		    strncmp(var, name, eq - var) == 0)
			return snprintf(val, val_len, "%s", value);
	}
	return -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_getenv);

int bcm47xx_nvram_gpio_pin(const char *name)
{
	int i, err;
	char nvram_var[] = "gpioXX";
	char buf[NVRAM_MAX_GPIO_VALUE_LEN];

	/* TODO: Optimize it to don't call getenv so many times */
	for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
		err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
		if (err <= 0)
			continue;
		err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
		if (err <= 0)
			continue;
		if (!strcmp(name, buf))
			return i;
	}
	return -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
Commit	Line	Data
121915c4 WB	1	/*
	2	* BCM947xx nvram variable access
	3	*
	4	* Copyright (C) 2005 Broadcom Corporation
	5	* Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
f36738dd	6	* Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
121915c4	7	*
70342287 RB	8	* This program is free software; you can redistribute it and/or modify it
70342287 RB	9	* under the terms of the GNU General Public License as published by the
121915c4 WB	10	* Free Software Foundation; either version 2 of the License, or (at your
	11	* option) any later version.
	12	*/
	13
50c97910	14	#include <linux/io.h>
121915c4 WB	15	#include <linux/types.h>
121915c4 WB	16	#include <linux/module.h>
121915c4 WB	17	#include <linux/kernel.h>
121915c4 WB	18	#include <linux/string.h>
9d1d0864	19	#include <linux/mtd/mtd.h>
138173d4	20	#include <linux/bcm47xx_nvram.h>
121915c4	21
d548ca6b RM	22	#define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */
	23	#define NVRAM_SPACE 0x8000
	24	#define NVRAM_MAX_GPIO_ENTRIES 32
	25	#define NVRAM_MAX_GPIO_VALUE_LEN 30
341097f1 RM	26
	27	#define FLASH_MIN 0x00020000 /* Minimum flash size */
	28
	29	struct nvram_header {
	30	u32 magic;
	31	u32 len;
	32	u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
	33	u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
	34	u32 config_ncdl; /* ncdl values for memc */
	35	};
	36
121915c4	37	static char nvram_buf[NVRAM_SPACE];
f4c4d589	38	static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
121915c4	39
8d602dd0	40	static u32 find_nvram_size(void __iomem *end)
f36738dd	41	{
8d602dd0	42	struct nvram_header __iomem *header;
f36738dd HM	43	int i;
	44
	45	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
8d602dd0	46	header = (struct nvram_header *)(end - nvram_sizes[i]);
341097f1	47	if (header->magic == NVRAM_MAGIC)
f36738dd HM	48	return nvram_sizes[i];
	49	}
	50
	51	return 0;
	52	}
	53
121915c4	54	/* Probe for NVRAM header */
8d602dd0	55	static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
121915c4	56	{
8d602dd0	57	struct nvram_header __iomem *header;
121915c4	58	int i;
08ccf572	59	u32 off;
121915c4	60	u32 src, dst;
f36738dd	61	u32 size;
121915c4	62
8d602dd0 RM	63	if (nvram_buf[0]) {
	64	pr_warn("nvram already initialized\n");
	65	return -EEXIST;
	66	}
	67
c4485671	68	/* TODO: when nvram is on nand flash check for bad blocks first. */
121915c4 WB	69	off = FLASH_MIN;
	70	while (off <= lim) {
	71	/* Windowed flash access */
8d602dd0	72	size = find_nvram_size(iobase + off);
f36738dd	73	if (size) {
8d602dd0	74	header = (struct nvram_header *)(iobase + off - size);
121915c4	75	goto found;
f36738dd	76	}
121915c4 WB	77	off <<= 1;
	78	}
	79
	80	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
8d602dd0	81	header = (struct nvram_header *)(iobase + 4096);
341097f1	82	if (header->magic == NVRAM_MAGIC) {
f36738dd	83	size = NVRAM_SPACE;
121915c4	84	goto found;
f36738dd	85	}
121915c4	86
8d602dd0	87	header = (struct nvram_header *)(iobase + 1024);
341097f1	88	if (header->magic == NVRAM_MAGIC) {
f36738dd	89	size = NVRAM_SPACE;
121915c4	90	goto found;
f36738dd	91	}
121915c4	92
f36738dd	93	pr_err("no nvram found\n");
cc4403e0	94	return -ENXIO;
121915c4 WB	95
121915c4 WB	96	found:
f36738dd HM	97	if (header->len > size)
	98	pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
	99	if (header->len > NVRAM_SPACE)
	100	pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
	101	header->len, NVRAM_SPACE);
	102
d548ca6b RM	103	src = (u32 *)header;
d548ca6b RM	104	dst = (u32 *)nvram_buf;
121915c4	105	for (i = 0; i < sizeof(struct nvram_header); i += 4)
23d2bc42	106	*dst++ = __raw_readl(src++);
f36738dd	107	for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
23d2bc42	108	*dst++ = readl(src++);
cc4403e0 HM	109
cc4403e0 HM	110	return 0;
121915c4 WB	111	}
121915c4 WB	112
21400f25 RM	113	/*
	114	* On bcm47xx we need access to the NVRAM very early, so we can't use mtd
	115	* subsystem to access flash. We can't even use platform device / driver to
	116	* store memory offset.
	117	* To handle this we provide following symbol. It's supposed to be called as
	118	* soon as we get info about flash device, before any NVRAM entry is needed.
	119	*/
	120	int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
8d602dd0 RM	121	{
	122	void __iomem *iobase;
	123	int err;
	124
	125	iobase = ioremap_nocache(base, lim);
	126	if (!iobase)
	127	return -ENOMEM;
	128
	129	err = nvram_find_and_copy(iobase, lim);
	130
	131	iounmap(iobase);
	132
	133	return err;
	134	}
	135
e58da16f	136	static int nvram_init(void)
bb765632	137	{
9d1d0864 RM	138	#ifdef CONFIG_MTD
	139	struct mtd_info *mtd;
	140	struct nvram_header header;
	141	size_t bytes_read;
	142	int err, i;
	143
	144	mtd = get_mtd_device_nm("nvram");
	145	if (IS_ERR(mtd))
	146	return -ENODEV;
	147
	148	for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
	149	loff_t from = mtd->size - nvram_sizes[i];
	150
	151	if (from < 0)
	152	continue;
	153
	154	err = mtd_read(mtd, from, sizeof(header), &bytes_read,
	155	(uint8_t *)&header);
341097f1	156	if (!err && header.magic == NVRAM_MAGIC) {
9d1d0864 RM	157	u8 dst = (uint8_t )nvram_buf;
	158	size_t len = header.len;
	159
	160	if (header.len > NVRAM_SPACE) {
	161	pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
	162	header.len, NVRAM_SPACE);
	163	len = NVRAM_SPACE;
	164	}
	165
	166	err = mtd_read(mtd, from, len, &bytes_read, dst);
	167	if (err)
	168	return err;
9d1d0864 RM	169
	170	return 0;
	171	}
	172	}
	173	#endif
7177efc5	174
cc4403e0	175	return -ENXIO;
bb765632 RM	176	}
bb765632 RM	177
341097f1	178	int bcm47xx_nvram_getenv(const char name, char val, size_t val_len)
121915c4 WB	179	{
121915c4 WB	180	char var, value, end, eq;
80aaaa8b	181	int data_left, err;
121915c4 WB	182
121915c4 WB	183	if (!name)
ee7e2f3c	184	return -EINVAL;
121915c4	185
cc4403e0	186	if (!nvram_buf[0]) {
e58da16f	187	err = nvram_init();
cc4403e0 HM	188	if (err)
	189	return err;
	190	}
121915c4 WB	191
	192	/* Look for name=value and return value */
	193	var = &nvram_buf[sizeof(struct nvram_header)];
	194	end = nvram_buf + sizeof(nvram_buf) - 2;
d548ca6b RM	195	end[0] = '\0';
d548ca6b RM	196	end[1] = '\0';
121915c4	197	for (; *var; var = value + strlen(value) + 1) {
80aaaa8b RM	198	data_left = end - var;
	199
	200	eq = strnchr(var, data_left, '=');
121915c4 WB	201	if (!eq)
	202	break;
	203	value = eq + 1;
d548ca6b RM	204	if (eq - var == strlen(name) &&
d548ca6b RM	205	strncmp(var, name, eq - var) == 0)
44d4b2ae	206	return snprintf(val, val_len, "%s", value);
50c97910	207	}
ee7e2f3c	208	return -ENOENT;
121915c4	209	}
111bd981	210	EXPORT_SYMBOL(bcm47xx_nvram_getenv);
62cf3bc0 HM	211
	212	int bcm47xx_nvram_gpio_pin(const char *name)
	213	{
	214	int i, err;
d548ca6b RM	215	char nvram_var[] = "gpioXX";
d548ca6b RM	216	char buf[NVRAM_MAX_GPIO_VALUE_LEN];
62cf3bc0	217
d548ca6b RM	218	/* TODO: Optimize it to don't call getenv so many times */
d548ca6b RM	219	for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
62cf3bc0 HM	220	err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
	221	if (err <= 0)
	222	continue;
	223	err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
	224	if (err <= 0)
	225	continue;
	226	if (!strcmp(name, buf))
	227	return i;
	228	}
	229	return -ENOENT;
	230	}
	231	EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);