target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c

   1 /*
   2  * MTD split for Broadcom Whole Flash Image
   3  *
   4  * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  *
  10  */
  11
  12 #define je16_to_cpu(x) ((x).v16)
  13 #define je32_to_cpu(x) ((x).v32)
  14
  15 #include <linux/crc32.h>
  16 #include <linux/init.h>
  17 #include <linux/jffs2.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/byteorder/generic.h>
  22 #include <linux/mtd/mtd.h>
  23 #include <linux/mtd/partitions.h>
  24
  25 #include "mtdsplit.h"
  26
  27 #define BCM_WFI_PARTS           4
  28
  29 #define CFERAM_NAME             "cferam"
  30 #define CFERAM_NAME_LEN         (sizeof(CFERAM_NAME) - 1)
  31 #define KERNEL_NAME             "vmlinux.lz"
  32 #define KERNEL_NAME_LEN         (sizeof(KERNEL_NAME) - 1)
  33 #define OPENWRT_NAME            "1-openwrt"
  34 #define OPENWRT_NAME_LEN        (sizeof(OPENWRT_NAME) - 1)
  35
  36 #define UBI_MAGIC               0x55424923
  37
  38 static u32 jffs2_dirent_crc(struct jffs2_raw_dirent *node)
  39 {
  40         return crc32(0, node, sizeof(struct jffs2_raw_dirent) - 8);
  41 }
  42
  43 static bool jffs2_dirent_valid(struct jffs2_raw_dirent *node)
  44 {
  45         return ((je16_to_cpu(node->magic) == JFFS2_MAGIC_BITMASK) &&
  46                 (je16_to_cpu(node->nodetype) == JFFS2_NODETYPE_DIRENT) &&
  47                 je32_to_cpu(node->ino) &&
  48                 je32_to_cpu(node->node_crc) == jffs2_dirent_crc(node));
  49 }
  50
  51 static int jffs2_find_file(struct mtd_info *master, uint8_t *buf,
  52                            const char *name, size_t name_len,
  53                            loff_t *offs)
  54 {
  55         struct jffs2_raw_dirent *node;
  56         bool valid = false;
  57         size_t retlen;
  58         uint16_t magic;
  59         int rc;
  60
  61         for (; *offs < master->size; *offs += master->erasesize) {
  62                 unsigned int block_offs = 0;
  63
  64                 /* Skip CFE erased blocks */
  65                 rc = mtd_read(master, *offs, sizeof(magic), &retlen,
  66                               (void *) &magic);
  67                 if (rc || retlen != sizeof(magic)) {
  68                         continue;
  69                 }
  70
  71                 /* Skip blocks not starting with JFFS2 magic */
  72                 if (magic != JFFS2_MAGIC_BITMASK)
  73                         continue;
  74
  75                 /* Read full block */
  76                 rc = mtd_read(master, *offs, master->erasesize, &retlen,
  77                               (void *) buf);
  78                 if (rc)
  79                         return rc;
  80                 if (retlen != master->erasesize)
  81                         return -EINVAL;
  82
  83                 while (block_offs < master->erasesize) {
  84                         node = (struct jffs2_raw_dirent *) &buf[block_offs];
  85
  86                         if (!jffs2_dirent_valid(node)) {
  87                                 block_offs += 4;
  88                                 continue;
  89                         }
  90
  91                         if (!memcmp(node->name, OPENWRT_NAME,
  92                                     OPENWRT_NAME_LEN))
  93                                 valid = true;
  94                         else if (!memcmp(node->name, name, name_len))
  95                                 return valid ? 0 : -EINVAL;
  96
  97                         block_offs += je32_to_cpu(node->totlen);
  98                         block_offs = (block_offs + 0x3) & ~0x3;
  99                 }
 100         }
 101
 102         return -ENOENT;
 103 }
 104
 105 static int ubifs_find(struct mtd_info *master, loff_t *offs)
 106 {
 107         uint32_t magic;
 108         size_t retlen;
 109         int rc;
 110
 111         for (; *offs < master->size; *offs += master->erasesize) {
 112                 rc = mtd_read(master, *offs, sizeof(magic), &retlen,
 113                               (unsigned char *) &magic);
 114                 if (rc || retlen != sizeof(magic))
 115                         continue;
 116
 117                 if (be32_to_cpu(magic) == UBI_MAGIC)
 118                         return 0;
 119         }
 120
 121         return -ENOENT;
 122 }
 123
 124 static int mtdsplit_parse_bcm_wfi(struct mtd_info *master,
 125                                   const struct mtd_partition **pparts,
 126                                   struct mtd_part_parser_data *data)
 127 {
 128         struct mtd_partition *parts;
 129         loff_t cfe_off, kernel_off, rootfs_off;
 130         uint8_t *buf;
 131         int ret;
 132
 133         buf = kzalloc(master->erasesize, GFP_KERNEL);
 134         if (!buf)
 135                 return -ENOMEM;
 136
 137         cfe_off = 0;
 138         ret = jffs2_find_file(master, buf, CFERAM_NAME, CFERAM_NAME_LEN,
 139                               &cfe_off);
 140         if (ret) {
 141                 kfree(buf);
 142                 return ret;
 143         }
 144
 145         kernel_off = cfe_off + master->erasesize;
 146         ret = jffs2_find_file(master, buf, KERNEL_NAME, KERNEL_NAME_LEN,
 147                               &kernel_off);
 148         kfree(buf);
 149         if (ret)
 150                 return ret;
 151
 152         rootfs_off = kernel_off + master->erasesize;
 153         ret = ubifs_find(master, &rootfs_off);
 154         if (ret)
 155                 return ret;
 156
 157         parts = kzalloc(BCM_WFI_PARTS * sizeof(*parts), GFP_KERNEL);
 158         if (!parts)
 159                 return -ENOMEM;
 160
 161         parts[0].name = "cferam";
 162         parts[0].mask_flags = MTD_WRITEABLE;
 163         parts[0].offset = 0;
 164         parts[0].size = kernel_off;
 165
 166         parts[1].name = "firmware";
 167         parts[1].offset = kernel_off;
 168         parts[1].size = master->size - kernel_off;
 169
 170         parts[2].name = KERNEL_PART_NAME;
 171         parts[2].offset = kernel_off;
 172         parts[2].size = rootfs_off - kernel_off;
 173
 174         parts[3].name = UBI_PART_NAME;
 175         parts[3].offset = rootfs_off;
 176         parts[3].size = master->size - rootfs_off;
 177
 178         *pparts = parts;
 179
 180         return BCM_WFI_PARTS;
 181 }
 182
 183 static const struct of_device_id mtdsplit_fit_of_match_table[] = {
 184         { .compatible = "brcm,wfi" },
 185         { },
 186 };
 187
 188 static struct mtd_part_parser mtdsplit_bcm_wfi_parser = {
 189         .owner = THIS_MODULE,
 190         .name = "bcm-wfi-fw",
 191         .of_match_table = mtdsplit_fit_of_match_table,
 192         .parse_fn = mtdsplit_parse_bcm_wfi,
 193         .type = MTD_PARSER_TYPE_FIRMWARE,
 194 };
 195
 196 static int __init mtdsplit_bcm_wfi_init(void)
 197 {
 198         register_mtd_parser(&mtdsplit_bcm_wfi_parser);
 199
 200         return 0;
 201 }
 202
 203 module_init(mtdsplit_bcm_wfi_init);