target/linux/generic/files/drivers/mtd/myloader.c

   1 /*
   2  *  Parse MyLoader-style flash partition tables and produce a Linux partition
   3  *  array to match.
   4  *
   5  *  Copyright (C) 2007-2009 Gabor Juhos <juhosg@openwrt.org>
   6  *
   7  *  This file was based on drivers/mtd/redboot.c
   8  *  Author: Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify it
  11  *  under the terms of the GNU General Public License version 2 as published
  12  *  by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/version.h>
  19 #include <linux/slab.h>
  20 #include <linux/init.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/mtd/mtd.h>
  23 #include <linux/mtd/partitions.h>
  24 #include <linux/byteorder/generic.h>
  25 #include <linux/myloader.h>
  26
  27 #define BLOCK_LEN_MIN           0x10000
  28 #define PART_NAME_LEN           32
  29
  30 struct part_data {
  31         struct mylo_partition_table     tab;
  32         char names[MYLO_MAX_PARTITIONS][PART_NAME_LEN];
  33 };
  34
  35 static int myloader_parse_partitions(struct mtd_info *master,
  36                                      struct mtd_partition **pparts,
  37                                      struct mtd_part_parser_data *data)
  38 {
  39         struct part_data *buf;
  40         struct mylo_partition_table *tab;
  41         struct mylo_partition *part;
  42         struct mtd_partition *mtd_parts;
  43         struct mtd_partition *mtd_part;
  44         int num_parts;
  45         int ret, i;
  46         size_t retlen;
  47         char *names;
  48         unsigned long offset;
  49         unsigned long blocklen;
  50
  51         buf = vmalloc(sizeof(*buf));
  52         if (!buf) {
  53                 return -ENOMEM;
  54                 goto out;
  55         }
  56         tab = &buf->tab;
  57
  58         blocklen = master->erasesize;
  59         if (blocklen < BLOCK_LEN_MIN)
  60                 blocklen = BLOCK_LEN_MIN;
  61
  62         offset = blocklen;
  63
  64         /* Find the partition table */
  65         for (i = 0; i < 4; i++, offset += blocklen) {
  66                 printk(KERN_DEBUG "%s: searching for MyLoader partition table"
  67                                 " at offset 0x%lx\n", master->name, offset);
  68
  69                 ret = mtd_read(master, offset, sizeof(*buf), &retlen,
  70                                (void *)buf);
  71                 if (ret)
  72                         goto out_free_buf;
  73
  74                 if (retlen != sizeof(*buf)) {
  75                         ret = -EIO;
  76                         goto out_free_buf;
  77                 }
  78
  79                 /* Check for Partition Table magic number */
  80                 if (tab->magic == le32_to_cpu(MYLO_MAGIC_PARTITIONS))
  81                         break;
  82
  83         }
  84
  85         if (tab->magic != le32_to_cpu(MYLO_MAGIC_PARTITIONS)) {
  86                 printk(KERN_DEBUG "%s: no MyLoader partition table found\n",
  87                         master->name);
  88                 ret = 0;
  89                 goto out_free_buf;
  90         }
  91
  92         /* The MyLoader and the Partition Table is always present */
  93         num_parts = 2;
  94
  95         /* Detect number of used partitions */
  96         for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
  97                 part = &tab->partitions[i];
  98
  99                 if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
 100                         continue;
 101
 102                 num_parts++;
 103         }
 104
 105         mtd_parts = kzalloc((num_parts * sizeof(*mtd_part) +
 106                                 num_parts * PART_NAME_LEN), GFP_KERNEL);
 107
 108         if (!mtd_parts) {
 109                 ret = -ENOMEM;
 110                 goto out_free_buf;
 111         }
 112
 113         mtd_part = mtd_parts;
 114         names = (char *)&mtd_parts[num_parts];
 115
 116         strncpy(names, "myloader", PART_NAME_LEN);
 117         mtd_part->name = names;
 118         mtd_part->offset = 0;
 119         mtd_part->size = offset;
 120         mtd_part->mask_flags = MTD_WRITEABLE;
 121         mtd_part++;
 122         names += PART_NAME_LEN;
 123
 124         strncpy(names, "partition_table", PART_NAME_LEN);
 125         mtd_part->name = names;
 126         mtd_part->offset = offset;
 127         mtd_part->size = blocklen;
 128         mtd_part->mask_flags = MTD_WRITEABLE;
 129         mtd_part++;
 130         names += PART_NAME_LEN;
 131
 132         for (i = 0; i < MYLO_MAX_PARTITIONS; i++) {
 133                 part = &tab->partitions[i];
 134
 135                 if (le16_to_cpu(part->type) == PARTITION_TYPE_FREE)
 136                         continue;
 137
 138                 if ((buf->names[i][0]) && (buf->names[i][0] != '\xff'))
 139                         strncpy(names, buf->names[i], PART_NAME_LEN);
 140                 else
 141                         snprintf(names, PART_NAME_LEN, "partition%d", i);
 142
 143                 mtd_part->offset = le32_to_cpu(part->addr);
 144                 mtd_part->size = le32_to_cpu(part->size);
 145                 mtd_part->name = names;
 146                 mtd_part++;
 147                 names += PART_NAME_LEN;
 148         }
 149
 150         *pparts = mtd_parts;
 151         ret = num_parts;
 152
 153  out_free_buf:
 154         vfree(buf);
 155  out:
 156         return ret;
 157 }
 158
 159 static struct mtd_part_parser myloader_mtd_parser = {
 160         .owner          = THIS_MODULE,
 161         .parse_fn       = myloader_parse_partitions,
 162         .name           = "MyLoader",
 163 };
 164
 165 static int __init myloader_mtd_parser_init(void)
 166 {
 167         return register_mtd_parser(&myloader_mtd_parser);
 168 }
 169
 170 static void __exit myloader_mtd_parser_exit(void)
 171 {
 172         deregister_mtd_parser(&myloader_mtd_parser);
 173 }
 174
 175 module_init(myloader_mtd_parser_init);
 176 module_exit(myloader_mtd_parser_exit);
 177
 178 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 179 MODULE_DESCRIPTION("Parsing code for MyLoader partition tables");
 180 MODULE_LICENSE("GPL v2");