2 * BCM947xx nvram variable access
4 * Copyright (C) 2005 Broadcom Corporation
5 * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
6 * Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
14 #include <linux/types.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/mtd/mtd.h>
19 #include <linux/bcm47xx_nvram.h>
21 #define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */
22 #define NVRAM_SPACE 0x8000
23 #define NVRAM_MAX_GPIO_ENTRIES 32
24 #define NVRAM_MAX_GPIO_VALUE_LEN 30
26 #define FLASH_MIN 0x00020000 /* Minimum flash size */
31 u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
32 u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
33 u32 config_ncdl; /* ncdl values for memc */
36 static char nvram_buf[NVRAM_SPACE];
37 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
39 static u32 find_nvram_size(void __iomem *end)
41 struct nvram_header __iomem *header;
44 for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
45 header = (struct nvram_header *)(end - nvram_sizes[i]);
46 if (header->magic == NVRAM_MAGIC)
47 return nvram_sizes[i];
53 /* Probe for NVRAM header */
54 static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
56 struct nvram_header __iomem *header;
63 pr_warn("nvram already initialized\n");
67 /* TODO: when nvram is on nand flash check for bad blocks first. */
70 /* Windowed flash access */
71 size = find_nvram_size(iobase + off);
73 header = (struct nvram_header *)(iobase + off - size);
79 /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
80 header = (struct nvram_header *)(iobase + 4096);
81 if (header->magic == NVRAM_MAGIC) {
86 header = (struct nvram_header *)(iobase + 1024);
87 if (header->magic == NVRAM_MAGIC) {
92 pr_err("no nvram found\n");
96 if (header->len > size)
97 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
98 if (header->len > NVRAM_SPACE)
99 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
100 header->len, NVRAM_SPACE);
103 dst = (u32 *)nvram_buf;
104 for (i = 0; i < sizeof(struct nvram_header); i += 4)
105 *dst++ = __raw_readl(src++);
106 for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
107 *dst++ = readl(src++);
113 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
114 * subsystem to access flash. We can't even use platform device / driver to
115 * store memory offset.
116 * To handle this we provide following symbol. It's supposed to be called as
117 * soon as we get info about flash device, before any NVRAM entry is needed.
119 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
121 void __iomem *iobase;
124 iobase = ioremap_nocache(base, lim);
128 err = nvram_find_and_copy(iobase, lim);
135 static int nvram_init(void)
138 struct mtd_info *mtd;
139 struct nvram_header header;
143 mtd = get_mtd_device_nm("nvram");
147 for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
148 loff_t from = mtd->size - nvram_sizes[i];
153 err = mtd_read(mtd, from, sizeof(header), &bytes_read,
155 if (!err && header.magic == NVRAM_MAGIC) {
156 u8 *dst = (uint8_t *)nvram_buf;
157 size_t len = header.len;
159 if (header.len > NVRAM_SPACE) {
160 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
161 header.len, NVRAM_SPACE);
165 err = mtd_read(mtd, from, len, &bytes_read, dst);
177 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
179 char *var, *value, *end, *eq;
191 /* Look for name=value and return value */
192 var = &nvram_buf[sizeof(struct nvram_header)];
193 end = nvram_buf + sizeof(nvram_buf) - 2;
196 for (; *var; var = value + strlen(value) + 1) {
197 data_left = end - var;
199 eq = strnchr(var, data_left, '=');
203 if (eq - var == strlen(name) &&
204 strncmp(var, name, eq - var) == 0)
205 return snprintf(val, val_len, "%s", value);
209 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
211 int bcm47xx_nvram_gpio_pin(const char *name)
214 char nvram_var[] = "gpioXX";
215 char buf[NVRAM_MAX_GPIO_VALUE_LEN];
217 /* TODO: Optimize it to don't call getenv so many times */
218 for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
219 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
222 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
225 if (!strcmp(name, buf))
230 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
232 MODULE_LICENSE("GPLv2");