nvram.c

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/*
 * BCM947xx nvram variable access
 *
 * Copyright (C) 2005 Broadcom Corporation
 * Copyright (C) 2006 Felix Fietkau <[email protected]>
 * Copyright (C) 2010-2011 Hauke Mehrtens <[email protected]>
 *
 * 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/init.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/ssb/ssb.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <asm/addrspace.h>
#include <asm/mach-bcm47xx/nvram.h>
#include <asm/mach-bcm47xx/bcm47xx.h>

static char nvram_buf[NVRAM_SPACE];

/* Probe for NVRAM header */
static void early_nvram_init(void)
{
#ifdef CONFIG_BCM47XX_SSB
    struct ssb_mipscore *mcore_ssb;
#endif
#ifdef CONFIG_BCM47XX_BCMA
    struct bcma_drv_cc *bcma_cc;
#endif
    struct nvram_header *header;
    int i;
    u32 base = 0;
    u32 lim = 0;
    u32 off;
    u32 *src, *dst;

    switch (bcm47xx_bus_type) {
#ifdef CONFIG_BCM47XX_SSB
    case BCM47XX_BUS_TYPE_SSB:
        mcore_ssb = &bcm47xx_bus.ssb.mipscore;
        base = mcore_ssb->flash_window;
        lim = mcore_ssb->flash_window_size;
        break;
#endif
#ifdef CONFIG_BCM47XX_BCMA
    case BCM47XX_BUS_TYPE_BCMA:
        bcma_cc = &bcm47xx_bus.bcma.bus.drv_cc;
        base = bcma_cc->pflash.window;
        lim = bcma_cc->pflash.window_size;
        break;
#endif
    }

    off = FLASH_MIN;
    while (off <= lim) {
        /* Windowed flash access */
        header = (struct nvram_header *)
            KSEG1ADDR(base + off - NVRAM_SPACE);
        if (header->magic == NVRAM_HEADER)
            goto found;
        off <<= 1;
    }

    /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
    header = (struct nvram_header *) KSEG1ADDR(base + 4096);
    if (header->magic == NVRAM_HEADER)
        goto found;

    header = (struct nvram_header *) KSEG1ADDR(base + 1024);
    if (header->magic == NVRAM_HEADER)
        goto found;

    return;

found:
    src = (u32 *) header;
    dst = (u32 *) nvram_buf;
    for (i = 0; i < sizeof(struct nvram_header); i += 4)
        *dst++ = *src++;
    for (; i < header->len && i < NVRAM_SPACE; i += 4)
        *dst++ = le32_to_cpu(*src++);
}

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

    if (!name)
        return NVRAM_ERR_INV_PARAM;

    if (!nvram_buf[0])
        early_nvram_init();

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