bcm63xxpart.c

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/*
 * BCM63XX CFE image tag parser
 *
 * Copyright © 2006-2008  Florian Fainelli <[email protected]>
 *            Mike Albon <[email protected]>
 * Copyright © 2009-2010  Daniel Dickinson <[email protected]>
 * Copyright © 2011-2012  Jonas Gorski <[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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/crc32.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>

#include <asm/mach-bcm63xx/bcm963xx_tag.h>
#include <asm/mach-bcm63xx/board_bcm963xx.h>

#define BCM63XX_EXTENDED_SIZE   0xBFC00000  /* Extended flash address */

#define BCM63XX_MIN_CFE_SIZE    0x10000     /* always at least 64KiB */
#define BCM63XX_MIN_NVRAM_SIZE  0x10000     /* always at least 64KiB */

#define BCM63XX_CFE_MAGIC_OFFSET 0x4e0

static int bcm63xx_detect_cfe(struct mtd_info *master)
{
    char buf[9];
    int ret;
    size_t retlen;

    ret = mtd_read(master, BCM963XX_CFE_VERSION_OFFSET, 5, &retlen,
               (void *)buf);
    buf[retlen] = 0;

    if (ret)
        return ret;

    if (strncmp("cfe-v", buf, 5) == 0)
        return 0;

    /* very old CFE's do not have the cfe-v string, so check for magic */
    ret = mtd_read(master, BCM63XX_CFE_MAGIC_OFFSET, 8, &retlen,
               (void *)buf);
    buf[retlen] = 0;

    return strncmp("CFE1CFE1", buf, 8);
}

static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
                    struct mtd_partition **pparts,
                    struct mtd_part_parser_data *data)
{
    /* CFE, NVRAM and global Linux are always present */
    int nrparts = 3, curpart = 0;
    struct bcm_tag *buf;
    struct mtd_partition *parts;
    int ret;
    size_t retlen;
    unsigned int rootfsaddr, kerneladdr, spareaddr;
    unsigned int rootfslen, kernellen, sparelen, totallen;
    unsigned int cfelen, nvramlen;
    int namelen = 0;
    int i;
    u32 computed_crc;
    bool rootfs_first = false;

    if (bcm63xx_detect_cfe(master))
        return -EINVAL;

    cfelen = max_t(uint32_t, master->erasesize, BCM63XX_MIN_CFE_SIZE);
    nvramlen = max_t(uint32_t, master->erasesize, BCM63XX_MIN_NVRAM_SIZE);

    /* Allocate memory for buffer */
    buf = vmalloc(sizeof(struct bcm_tag));
    if (!buf)
        return -ENOMEM;

    /* Get the tag */
    ret = mtd_read(master, cfelen, sizeof(struct bcm_tag), &retlen,
               (void *)buf);

    if (retlen != sizeof(struct bcm_tag)) {
        vfree(buf);
        return -EIO;
    }

    computed_crc = crc32_le(IMAGETAG_CRC_START, (u8 *)buf,
                offsetof(struct bcm_tag, header_crc));
    if (computed_crc == buf->header_crc) {
        char *boardid = &(buf->board_id[0]);
        char *tagversion = &(buf->tag_version[0]);

        sscanf(buf->flash_image_start, "%u", &rootfsaddr);
        sscanf(buf->kernel_address, "%u", &kerneladdr);
        sscanf(buf->kernel_length, "%u", &kernellen);
        sscanf(buf->total_length, "%u", &totallen);

        pr_info("CFE boot tag found with version %s and board type %s\n",
            tagversion, boardid);

        kerneladdr = kerneladdr - BCM63XX_EXTENDED_SIZE;
        rootfsaddr = rootfsaddr - BCM63XX_EXTENDED_SIZE;
        spareaddr = roundup(totallen, master->erasesize) + cfelen;
        sparelen = master->size - spareaddr - nvramlen;

        if (rootfsaddr < kerneladdr) {
            /* default Broadcom layout */
            rootfslen = kerneladdr - rootfsaddr;
            rootfs_first = true;
        } else {
            /* OpenWrt layout */
            rootfsaddr = kerneladdr + kernellen;
            rootfslen = spareaddr - rootfsaddr;
        }
    } else {
        pr_warn("CFE boot tag CRC invalid (expected %08x, actual %08x)\n",
            buf->header_crc, computed_crc);
        kernellen = 0;
        rootfslen = 0;
        rootfsaddr = 0;
        spareaddr = cfelen;
        sparelen = master->size - cfelen - nvramlen;
    }

    /* Determine number of partitions */
    namelen = 8;
    if (rootfslen > 0) {
        nrparts++;
        namelen += 6;
    }
    if (kernellen > 0) {
        nrparts++;
        namelen += 6;
    }

    /* Ask kernel for more memory */
    parts = kzalloc(sizeof(*parts) * nrparts + 10 * nrparts, GFP_KERNEL);
    if (!parts) {
        vfree(buf);
        return -ENOMEM;
    }

    /* Start building partition list */
    parts[curpart].name = "CFE";
    parts[curpart].offset = 0;
    parts[curpart].size = cfelen;
    curpart++;

    if (kernellen > 0) {
        int kernelpart = curpart;

        if (rootfslen > 0 && rootfs_first)
            kernelpart++;
        parts[kernelpart].name = "kernel";
        parts[kernelpart].offset = kerneladdr;
        parts[kernelpart].size = kernellen;
        curpart++;
    }

    if (rootfslen > 0) {
        int rootfspart = curpart;

        if (kernellen > 0 && rootfs_first)
            rootfspart--;
        parts[rootfspart].name = "rootfs";
        parts[rootfspart].offset = rootfsaddr;
        parts[rootfspart].size = rootfslen;
        if (sparelen > 0  && !rootfs_first)
            parts[rootfspart].size += sparelen;
        curpart++;
    }

    parts[curpart].name = "nvram";
    parts[curpart].offset = master->size - nvramlen;
    parts[curpart].size = nvramlen;

    /* Global partition "linux" to make easy firmware upgrade */
    curpart++;
    parts[curpart].name = "linux";
    parts[curpart].offset = cfelen;
    parts[curpart].size = master->size - cfelen - nvramlen;

    for (i = 0; i < nrparts; i++)
        pr_info("Partition %d is %s offset %lx and length %lx\n", i,
            parts[i].name, (long unsigned int)(parts[i].offset),
            (long unsigned int)(parts[i].size));

    pr_info("Spare partition is offset %x and length %x\n", spareaddr,
        sparelen);

    *pparts = parts;
    vfree(buf);

    return nrparts;
};

static struct mtd_part_parser bcm63xx_cfe_parser = {
    .owner = THIS_MODULE,
    .parse_fn = bcm63xx_parse_cfe_partitions,
    .name = "bcm63xxpart",
};

static int __init bcm63xx_cfe_parser_init(void)
{
    return register_mtd_parser(&bcm63xx_cfe_parser);
}

static void __exit bcm63xx_cfe_parser_exit(void)
{
    deregister_mtd_parser(&bcm63xx_cfe_parser);
}

module_init(bcm63xx_cfe_parser_init);
module_exit(bcm63xx_cfe_parser_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Dickinson <[email protected]>");
MODULE_AUTHOR("Florian Fainelli <[email protected]>");
MODULE_AUTHOR("Mike Albon <[email protected]>");
MODULE_AUTHOR("Jonas Gorski <[email protected]");
MODULE_DESCRIPTION("MTD partitioning for BCM63XX CFE bootloaders");