ar7part.c

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/*
 * Copyright © 2007 Eugene Konev <[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
 *
 * TI AR7 flash partition table.
 * Based on ar7 map by Felix Fietkau <[email protected]>
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/bootmem.h>
#include <linux/magic.h>
#include <linux/module.h>

#define AR7_PARTS   4
#define ROOT_OFFSET 0xe0000

#define LOADER_MAGIC1   le32_to_cpu(0xfeedfa42)
#define LOADER_MAGIC2   le32_to_cpu(0xfeed1281)

#ifndef SQUASHFS_MAGIC
#define SQUASHFS_MAGIC  0x73717368
#endif

struct ar7_bin_rec {
    unsigned int checksum;
    unsigned int length;
    unsigned int address;
};

static int create_mtd_partitions(struct mtd_info *master,
                 struct mtd_partition **pparts,
                 struct mtd_part_parser_data *data)
{
    struct ar7_bin_rec header;
    unsigned int offset;
    size_t len;
    unsigned int pre_size = master->erasesize, post_size = 0;
    unsigned int root_offset = ROOT_OFFSET;

    int retries = 10;
    struct mtd_partition *ar7_parts;

    ar7_parts = kzalloc(sizeof(*ar7_parts) * AR7_PARTS, GFP_KERNEL);
    if (!ar7_parts)
        return -ENOMEM;
    ar7_parts[0].name = "loader";
    ar7_parts[0].offset = 0;
    ar7_parts[0].size = master->erasesize;
    ar7_parts[0].mask_flags = MTD_WRITEABLE;

    ar7_parts[1].name = "config";
    ar7_parts[1].offset = 0;
    ar7_parts[1].size = master->erasesize;
    ar7_parts[1].mask_flags = 0;

    do { /* Try 10 blocks starting from master->erasesize */
        offset = pre_size;
        mtd_read(master, offset, sizeof(header), &len,
             (uint8_t *)&header);
        if (!strncmp((char *)&header, "TIENV0.8", 8))
            ar7_parts[1].offset = pre_size;
        if (header.checksum == LOADER_MAGIC1)
            break;
        if (header.checksum == LOADER_MAGIC2)
            break;
        pre_size += master->erasesize;
    } while (retries--);

    pre_size = offset;

    if (!ar7_parts[1].offset) {
        ar7_parts[1].offset = master->size - master->erasesize;
        post_size = master->erasesize;
    }

    switch (header.checksum) {
    case LOADER_MAGIC1:
        while (header.length) {
            offset += sizeof(header) + header.length;
            mtd_read(master, offset, sizeof(header), &len,
                 (uint8_t *)&header);
        }
        root_offset = offset + sizeof(header) + 4;
        break;
    case LOADER_MAGIC2:
        while (header.length) {
            offset += sizeof(header) + header.length;
            mtd_read(master, offset, sizeof(header), &len,
                 (uint8_t *)&header);
        }
        root_offset = offset + sizeof(header) + 4 + 0xff;
        root_offset &= ~(uint32_t)0xff;
        break;
    default:
        printk(KERN_WARNING "Unknown magic: %08x\n", header.checksum);
        break;
    }

    mtd_read(master, root_offset, sizeof(header), &len, (u8 *)&header);
    if (header.checksum != SQUASHFS_MAGIC) {
        root_offset += master->erasesize - 1;
        root_offset &= ~(master->erasesize - 1);
    }

    ar7_parts[2].name = "linux";
    ar7_parts[2].offset = pre_size;
    ar7_parts[2].size = master->size - pre_size - post_size;
    ar7_parts[2].mask_flags = 0;

    ar7_parts[3].name = "rootfs";
    ar7_parts[3].offset = root_offset;
    ar7_parts[3].size = master->size - root_offset - post_size;
    ar7_parts[3].mask_flags = 0;

    *pparts = ar7_parts;
    return AR7_PARTS;
}

static struct mtd_part_parser ar7_parser = {
    .owner = THIS_MODULE,
    .parse_fn = create_mtd_partitions,
    .name = "ar7part",
};

static int __init ar7_parser_init(void)
{
    return register_mtd_parser(&ar7_parser);
}

module_init(ar7_parser_init);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(  "Felix Fietkau <[email protected]>, "
        "Eugene Konev <[email protected]>");
MODULE_DESCRIPTION("MTD partitioning for TI AR7");