bcm47xx: prepare to support different buses
[deliverable/linux.git] / arch / mips / bcm47xx / nvram.c
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1/*
2 * BCM947xx nvram variable access
3 *
4 * Copyright (C) 2005 Broadcom Corporation
5 * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
fe6f3642 6 * Copyright (C) 2010-2011 Hauke Mehrtens <hauke@hauke-m.de>
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7 *
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.
12 */
13
14#include <linux/init.h>
15#include <linux/types.h>
16#include <linux/module.h>
17#include <linux/ssb/ssb.h>
18#include <linux/kernel.h>
19#include <linux/string.h>
20#include <asm/addrspace.h>
21#include <asm/mach-bcm47xx/nvram.h>
22#include <asm/mach-bcm47xx/bcm47xx.h>
23
24static char nvram_buf[NVRAM_SPACE];
25
26/* Probe for NVRAM header */
fe6f3642 27static void early_nvram_init(void)
121915c4 28{
08ccf572 29 struct ssb_mipscore *mcore_ssb;
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30 struct nvram_header *header;
31 int i;
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32 u32 base = 0;
33 u32 lim = 0;
34 u32 off;
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35 u32 *src, *dst;
36
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37 switch (bcm47xx_bus_type) {
38 case BCM47XX_BUS_TYPE_SSB:
39 mcore_ssb = &bcm47xx_bus.ssb.mipscore;
40 base = mcore_ssb->flash_window;
41 lim = mcore_ssb->flash_window_size;
42 break;
43 }
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44
45 off = FLASH_MIN;
46 while (off <= lim) {
47 /* Windowed flash access */
48 header = (struct nvram_header *)
49 KSEG1ADDR(base + off - NVRAM_SPACE);
50 if (header->magic == NVRAM_HEADER)
51 goto found;
52 off <<= 1;
53 }
54
55 /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
56 header = (struct nvram_header *) KSEG1ADDR(base + 4096);
57 if (header->magic == NVRAM_HEADER)
58 goto found;
59
60 header = (struct nvram_header *) KSEG1ADDR(base + 1024);
61 if (header->magic == NVRAM_HEADER)
62 goto found;
63
64 return;
65
66found:
67 src = (u32 *) header;
68 dst = (u32 *) nvram_buf;
69 for (i = 0; i < sizeof(struct nvram_header); i += 4)
70 *dst++ = *src++;
71 for (; i < header->len && i < NVRAM_SPACE; i += 4)
72 *dst++ = le32_to_cpu(*src++);
73}
74
75int nvram_getenv(char *name, char *val, size_t val_len)
76{
77 char *var, *value, *end, *eq;
78
79 if (!name)
47a34861 80 return NVRAM_ERR_INV_PARAM;
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81
82 if (!nvram_buf[0])
83 early_nvram_init();
84
85 /* Look for name=value and return value */
86 var = &nvram_buf[sizeof(struct nvram_header)];
87 end = nvram_buf + sizeof(nvram_buf) - 2;
88 end[0] = end[1] = '\0';
89 for (; *var; var = value + strlen(value) + 1) {
90 eq = strchr(var, '=');
91 if (!eq)
92 break;
93 value = eq + 1;
94 if ((eq - var) == strlen(name) &&
95 strncmp(var, name, (eq - var)) == 0) {
96 snprintf(val, val_len, "%s", value);
97 return 0;
98 }
99 }
47a34861 100 return NVRAM_ERR_ENVNOTFOUND;
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101}
102EXPORT_SYMBOL(nvram_getenv);
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