drivers/mtd/redboot.c

   1 /*
   2  * $Id: redboot.c,v 1.6 2001/10/25 09:16:06 dwmw2 Exp $
   3  *
   4  * Parse RedBoot-style Flash Image System (FIS) tables and
   5  * produce a Linux partition array to match.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10
  11 #include <linux/mtd/mtd.h>
  12 #include <linux/mtd/partitions.h>
  13
  14 struct fis_image_desc {
  15     unsigned char name[16];      // Null terminated name
  16     unsigned long flash_base;    // Address within FLASH of image
  17     unsigned long mem_base;      // Address in memory where it executes
  18     unsigned long size;          // Length of image
  19     unsigned long entry_point;   // Execution entry point
  20     unsigned long data_length;   // Length of actual data
  21     unsigned char _pad[256-(16+7*sizeof(unsigned long))];
  22     unsigned long desc_cksum;    // Checksum over image descriptor
  23     unsigned long file_cksum;    // Checksum over image data
  24 };
  25
  26 struct fis_list {
  27         struct fis_image_desc *img;
  28         struct fis_list *next;
  29 };
  30
  31 static inline int redboot_checksum(struct fis_image_desc *img)
  32 {
  33         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  34         return 1;
  35 }
  36
  37 int parse_redboot_partitions(struct mtd_info *master, struct mtd_partition **pparts)
  38 {
  39         int nrparts = 0;
  40         struct fis_image_desc *buf;
  41         struct mtd_partition *parts;
  42         struct fis_list *fl = NULL, *tmp_fl;
  43         int ret, i;
  44         size_t retlen;
  45         char *names;
  46         int namelen = 0;
  47
  48         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  49
  50         if (!buf)
  51                 return -ENOMEM;
  52
  53         /* Read the start of the last erase block */
  54         ret = master->read(master, master->size - master->erasesize,
  55                            PAGE_SIZE, &retlen, (void *)buf);
  56
  57         if (ret)
  58                 goto out;
  59
  60         if (retlen != PAGE_SIZE) {
  61                 ret = -EIO;
  62                 goto out;
  63         }
  64
  65         /* RedBoot image could appear in any of the first three slots */
  66         for (i = 0; i < 3; i++) {
  67                 if (!memcmp(buf[i].name, "RedBoot", 8))
  68                         break;
  69         }
  70         if (i == 3) {
  71                 /* Didn't find it */
  72                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
  73                        master->name);
  74                 ret = 0;
  75                 goto out;
  76         }
  77
  78         for (i = 0; i < PAGE_SIZE / sizeof(struct fis_image_desc); i++) {
  79                 struct fis_list *new_fl, **prev;
  80
  81                 if (buf[i].name[0] == 0xff)
  82                         break;
  83                 if (!redboot_checksum(&buf[i]))
  84                         break;
  85
  86                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
  87                 namelen += strlen(buf[i].name)+1;
  88                 if (!new_fl) {
  89                         ret = -ENOMEM;
  90                         goto out;
  91                 }
  92                 new_fl->img = &buf[i];
  93                 buf[i].flash_base &= master->size-1;
  94
  95                 /* I'm sure the JFFS2 code has done me permanent damage.
  96                  * I now think the following is _normal_
  97                  */
  98                 prev = &fl;
  99                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 100                         prev = &(*prev)->next;
 101                 new_fl->next = *prev;
 102                 *prev = new_fl;
 103
 104                 nrparts++;
 105         }
 106         if (fl->img->flash_base)
 107                 nrparts++;
 108
 109         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 110                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize < tmp_fl->next->img->flash_base)
 111                         nrparts++;
 112         }
 113         parts = kmalloc(sizeof(*parts)*nrparts + namelen, GFP_KERNEL);
 114
 115         if (!parts) {
 116                 ret = -ENOMEM;
 117                 goto out;
 118         }
 119         names = (char *)&parts[nrparts];
 120         memset(parts, 0, sizeof(*parts)*nrparts + namelen);
 121         i=0;
 122
 123         if (fl->img->flash_base) {
 124                parts[0].name = "unallocated space";
 125                parts[0].size = fl->img->flash_base;
 126                parts[0].offset = 0;
 127         }
 128         for ( ; i<nrparts; i++) {
 129                 parts[i].size = fl->img->size;
 130                 parts[i].offset = fl->img->flash_base;
 131                 parts[i].name = names;
 132
 133                 strcpy(names, fl->img->name);
 134                 names += strlen(names)+1;
 135
 136                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize < fl->next->img->flash_base) {
 137                         i++;
 138                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 139                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 140                         parts[i].name = "unallocated space";
 141                 }
 142                 tmp_fl = fl;
 143                 fl = fl->next;
 144                 kfree(tmp_fl);
 145         }
 146         ret = nrparts;
 147         *pparts = parts;
 148  out:
 149         while (fl) {
 150                 struct fis_list *old = fl;
 151                 fl = fl->next;
 152                 kfree(old);
 153         }
 154         kfree(buf);
 155         return ret;
 156 }
 157
 158 EXPORT_SYMBOL(parse_redboot_partitions);
 159
 160 MODULE_LICENSE("GPL");
 161 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 162 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");