summaryrefslogtreecommitdiff
path: root/drivers/firmware/broadcom/bcm47xx_nvram.c
blob: bd235833b687563930bec8ceb3cf3af1495b84ea (plain)
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
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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>
 */

#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			0x10000
#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 size_t nvram_len;
static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};

/**
 * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
 */
static bool bcm47xx_nvram_is_valid(void __iomem *nvram)
{
	return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
}

/**
 * bcm47xx_nvram_copy - copy NVRAM to internal buffer
 */
static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size)
{
	struct nvram_header __iomem *header = nvram_start;
	size_t copy_size;

	copy_size = header->len;
	if (copy_size > res_size) {
		pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
		copy_size = res_size;
	}
	if (copy_size >= NVRAM_SPACE) {
		pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
		       copy_size, NVRAM_SPACE - 1);
		copy_size = NVRAM_SPACE - 1;
	}

	__ioread32_copy(nvram_buf, nvram_start, DIV_ROUND_UP(copy_size, 4));
	nvram_buf[NVRAM_SPACE - 1] = '\0';
	nvram_len = copy_size;
}

/**
 * bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it
 */
static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size)
{
	size_t flash_size;
	size_t offset;
	int i;

	if (nvram_len) {
		pr_warn("nvram already initialized\n");
		return -EEXIST;
	}

	/* TODO: when nvram is on nand flash check for bad blocks first. */

	/* Try every possible flash size and check for NVRAM at its end */
	for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) {
		for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
			offset = flash_size - nvram_sizes[i];
			if (bcm47xx_nvram_is_valid(flash_start + offset))
				goto found;
		}
	}

	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */

	offset = 4096;
	if (bcm47xx_nvram_is_valid(flash_start + offset))
		goto found;

	offset = 1024;
	if (bcm47xx_nvram_is_valid(flash_start + offset))
		goto found;

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

found:
	bcm47xx_nvram_copy(flash_start + offset, res_size - offset);

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

	err = bcm47xx_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;

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

	err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
	if (!err && header.magic == NVRAM_MAGIC &&
	    header.len > sizeof(header)) {
		nvram_len = header.len;
		if (nvram_len >= NVRAM_SPACE) {
			pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
				nvram_len, NVRAM_SPACE);
			nvram_len = NVRAM_SPACE - 1;
		}

		err = mtd_read(mtd, 0, nvram_len, &nvram_len,
			       (u8 *)nvram_buf);
		return err;
	}
#endif

	return -ENXIO;
}

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

	if (!name)
		return -EINVAL;

	if (!nvram_len) {
		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);
	while (var < end && *var) {
		eq = strchr(var, '=');
		if (!eq)
			break;
		value = eq + 1;
		if (eq - var == strlen(name) &&
		    strncmp(var, name, eq - var) == 0)
			return snprintf(val, val_len, "%s", value);
		var = value + strlen(value) + 1;
	}
	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);

char *bcm47xx_nvram_get_contents(size_t *nvram_size)
{
	int err;
	char *nvram;

	if (!nvram_len) {
		err = nvram_init();
		if (err)
			return NULL;
	}

	*nvram_size = nvram_len - sizeof(struct nvram_header);
	nvram = vmalloc(*nvram_size);
	if (!nvram)
		return NULL;
	memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size);

	return nvram;
}
EXPORT_SYMBOL(bcm47xx_nvram_get_contents);

MODULE_LICENSE("GPL v2");