/*
 * 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/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 <bcm47xx_nvram.h>
#include <asm/mach-bcm47xx/bcm47xx.h>

static char nvram_buf[NVRAM_SPACE];

static u32 find_nvram_size(u32 end)
{
        struct nvram_header *header;
        u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
        int i;

        for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
                header = (struct nvram_header *)KSEG1ADDR(end - nvram_sizes[i]);
                if (header->magic == NVRAM_HEADER)
                        return nvram_sizes[i];
        }

        return 0;
}

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

        /* 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(base + off);
                if (size) {
                        header = (struct nvram_header *)KSEG1ADDR(base + off -
                                                                  size);
                        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) {
                size = NVRAM_SPACE;
                goto found;
        }

        header = (struct nvram_header *) KSEG1ADDR(base + 1024);
        if (header->magic == NVRAM_HEADER) {
                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++ = *src++;
        for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
                *dst++ = le32_to_cpu(*src++);
        memset(dst, 0x0, NVRAM_SPACE - i);

        return 0;
}

#ifdef CONFIG_BCM47XX_SSB
static int nvram_init_ssb(void)
{
        struct ssb_mipscore *mcore = &bcm47xx_bus.ssb.mipscore;
        u32 base;
        u32 lim;

        if (mcore->pflash.present) {
                base = mcore->pflash.window;
                lim = mcore->pflash.window_size;
        } else {
                pr_err("Couldn't find supported flash memory\n");
                return -ENXIO;
        }

        return nvram_find_and_copy(base, lim);
}
#endif

#ifdef CONFIG_BCM47XX_BCMA
static int nvram_init_bcma(void)
{
        struct bcma_drv_cc *cc = &bcm47xx_bus.bcma.bus.drv_cc;
        u32 base;
        u32 lim;

#ifdef CONFIG_BCMA_NFLASH
        if (cc->nflash.boot) {
                base = BCMA_SOC_FLASH1;
                lim = BCMA_SOC_FLASH1_SZ;
        } else
#endif
        if (cc->pflash.present) {
                base = cc->pflash.window;
                lim = cc->pflash.window_size;
#ifdef CONFIG_BCMA_SFLASH
        } else if (cc->sflash.present) {
                base = cc->sflash.window;
                lim = cc->sflash.size;
#endif
        } else {
                pr_err("Couldn't find supported flash memory\n");
                return -ENXIO;
        }

        return nvram_find_and_copy(base, lim);
}
#endif

static int nvram_init(void)
{
        switch (bcm47xx_bus_type) {
#ifdef CONFIG_BCM47XX_SSB
        case BCM47XX_BUS_TYPE_SSB:
                return nvram_init_ssb();
#endif
#ifdef CONFIG_BCM47XX_BCMA
        case BCM47XX_BUS_TYPE_BCMA:
                return nvram_init_bcma();
#endif
        }
        return -ENXIO;
}

int bcm47xx_nvram_getenv(char *name, char *val, size_t val_len)
{
        char *var, *value, *end, *eq;
        int 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] = 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 -ENOENT;
}
EXPORT_SYMBOL(bcm47xx_nvram_getenv);