target/linux/adm5120/files-3.18/drivers/mtd/trxsplit.c

   1 /*
   2  *  Copyright (C) Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  *  This program is free software; you can redistribute it and/or modify it
   5  *  under the terms of the GNU General Public License version 2 as published
   6  *  by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/list.h>
  15 #include <linux/kmod.h>
  16 #include <linux/root_dev.h>
  17
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/partitions.h>
  20
  21 #include <linux/byteorder/generic.h>
  22
  23 #define PFX     "trxsplit: "
  24
  25 #define TRX_MAGIC       0x30524448      /* "HDR0" */
  26 #define TRX_VERSION     1
  27 #define TRX_MAX_LEN     0x3A0000
  28 #define TRX_NO_HEADER   0x1     /* do not write TRX header */
  29 #define TRX_GZ_FILES    0x2     /* contains individual gzip files */
  30 #define TRX_MAX_OFFSET  3
  31 #define TRX_MIN_KERNEL_SIZE     (256 * 1024)
  32
  33 struct trx_header {
  34         u32 magic;      /* "HDR0" */
  35         u32 len;        /* Length of file including header */
  36         u32 crc32;      /* 32-bit CRC from flag_version to end of file */
  37         u32 flag_version; /* 0:15 flags, 16:31 version */
  38         u32 offsets[TRX_MAX_OFFSET]; /* Offsets of partitions */
  39 };
  40
  41 #define TRX_ALIGN       0x1000
  42
  43 static int trx_nr_parts;
  44 static unsigned long trx_offset;
  45 static struct mtd_info *trx_mtd;
  46 static struct mtd_partition trx_parts[TRX_MAX_OFFSET];
  47 static struct trx_header trx_hdr;
  48
  49 static int trxsplit_refresh_partitions(struct mtd_info *mtd);
  50
  51 static int trxsplit_checktrx(struct mtd_info *mtd, unsigned long offset)
  52 {
  53         size_t retlen;
  54         int err;
  55
  56         err = mtd_read(mtd, offset, sizeof(trx_hdr), &retlen, (void *)&trx_hdr);
  57         if (err) {
  58                 printk(KERN_ALERT PFX "unable to read from '%s'\n", mtd->name);
  59                 goto err_out;
  60         }
  61
  62         if (retlen != sizeof(trx_hdr)) {
  63                 printk(KERN_ALERT PFX "reading failed on '%s'\n", mtd->name);
  64                 goto err_out;
  65         }
  66
  67         trx_hdr.magic = le32_to_cpu(trx_hdr.magic);
  68         trx_hdr.len = le32_to_cpu(trx_hdr.len);
  69         trx_hdr.crc32 = le32_to_cpu(trx_hdr.crc32);
  70         trx_hdr.flag_version = le32_to_cpu(trx_hdr.flag_version);
  71         trx_hdr.offsets[0] = le32_to_cpu(trx_hdr.offsets[0]);
  72         trx_hdr.offsets[1] = le32_to_cpu(trx_hdr.offsets[1]);
  73         trx_hdr.offsets[2] = le32_to_cpu(trx_hdr.offsets[2]);
  74
  75         /* sanity checks */
  76         if (trx_hdr.magic != TRX_MAGIC)
  77                 goto err_out;
  78
  79         if (trx_hdr.len > mtd->size - offset)
  80                 goto err_out;
  81
  82         /* TODO: add crc32 checking too? */
  83
  84         return 0;
  85
  86 err_out:
  87         return -1;
  88 }
  89
  90 static void trxsplit_findtrx(struct mtd_info *mtd)
  91 {
  92         unsigned long offset;
  93         int err;
  94
  95         printk(KERN_INFO PFX "searching TRX header in '%s'\n", mtd->name);
  96
  97         err = 0;
  98         for (offset = 0; offset < mtd->size; offset += TRX_ALIGN) {
  99                 err = trxsplit_checktrx(mtd, offset);
 100                 if (err == 0)
 101                         break;
 102         }
 103
 104         if (err)
 105                 return;
 106
 107         printk(KERN_INFO PFX "TRX header found at 0x%lX\n", offset);
 108
 109         trx_mtd = mtd;
 110         trx_offset = offset;
 111 }
 112
 113 static void trxsplit_create_partitions(struct mtd_info *mtd)
 114 {
 115         struct mtd_partition *part = trx_parts;
 116         int err;
 117         int i;
 118
 119         for (i = 0; i < TRX_MAX_OFFSET; i++) {
 120                 part = &trx_parts[i];
 121                 if (trx_hdr.offsets[i] == 0)
 122                         continue;
 123                 part->offset = trx_offset + trx_hdr.offsets[i];
 124                 trx_nr_parts++;
 125         }
 126
 127         for (i = 0; i < trx_nr_parts-1; i++)
 128                 trx_parts[i].size = trx_parts[i+1].offset - trx_parts[i].offset;
 129
 130         trx_parts[i].size = mtd->size - trx_parts[i].offset;
 131
 132         i = 0;
 133         part = &trx_parts[i];
 134         if (part->size < TRX_MIN_KERNEL_SIZE) {
 135                 part->name = "loader";
 136                 i++;
 137         }
 138
 139         part = &trx_parts[i];
 140         part->name = "kernel";
 141         i++;
 142
 143         part = &trx_parts[i];
 144         part->name = "rootfs";
 145
 146         err = mtd_device_register(mtd, trx_parts, trx_nr_parts);
 147         if (err) {
 148                 printk(KERN_ALERT PFX "adding TRX partitions failed\n");
 149                 return;
 150         }
 151
 152         mtd->refresh_device = trxsplit_refresh_partitions;
 153 }
 154
 155 static int trxsplit_refresh_partitions(struct mtd_info *mtd)
 156 {
 157         printk(KERN_INFO PFX "refreshing TRX partitions in '%s' (%d,%d)\n",
 158                 mtd->name, MTD_BLOCK_MAJOR, mtd->index);
 159
 160         /* remove old partitions */
 161         mtd_device_unregister(mtd);
 162
 163         trxsplit_findtrx(mtd);
 164         if (!trx_mtd)
 165                 goto err;
 166
 167         trxsplit_create_partitions(trx_mtd);
 168         return 1;
 169
 170 err:
 171         return 0;
 172 }
 173
 174 static void __init trxsplit_add_mtd(struct mtd_info *mtd)
 175 {
 176         if (mtd->type != MTD_NORFLASH) {
 177                 printk(KERN_INFO PFX "'%s' is not a NOR flash, skipped\n",
 178                                 mtd->name);
 179                 return;
 180         }
 181
 182         if (!trx_mtd)
 183                 trxsplit_findtrx(mtd);
 184 }
 185
 186 static void __init trxsplit_remove_mtd(struct mtd_info *mtd)
 187 {
 188         /* nothing to do */
 189 }
 190
 191 static struct mtd_notifier trxsplit_notifier __initdata = {
 192         .add    = trxsplit_add_mtd,
 193         .remove = trxsplit_remove_mtd,
 194 };
 195
 196 static void __init trxsplit_scan(void)
 197 {
 198         register_mtd_user(&trxsplit_notifier);
 199         unregister_mtd_user(&trxsplit_notifier);
 200 }
 201
 202 static int __init trxsplit_init(void)
 203 {
 204         trxsplit_scan();
 205
 206         if (trx_mtd) {
 207                 printk(KERN_INFO PFX "creating TRX partitions in '%s' "
 208                         "(%d,%d)\n", trx_mtd->name, MTD_BLOCK_MAJOR,
 209                         trx_mtd->index);
 210                 trxsplit_create_partitions(trx_mtd);
 211         }
 212
 213         return 0;
 214 }
 215
 216 late_initcall(trxsplit_init);