target/linux/adm8668/files/drivers/mtd/maps/adm8668.c

   1 /*
   2  * Copyright (C) 2010 Scott Nicholas <neutronscott@scottn.us>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/types.h>
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/mtd/mtd.h>
  24 #include <linux/mtd/map.h>
  25 #include <linux/mtd/partitions.h>
  26 #include <linux/magic.h>
  27 #include <asm/io.h>
  28
  29 #define FLASH_SIZE      0x800000
  30 #define FLASH_PHYS_ADDR 0x10000000
  31
  32 /* just interested in part of the full struct */
  33 struct squashfs_super_block {
  34         __le32  s_magic;
  35         __le32  pad0[9];        /* it's not really padding */
  36         __le64  bytes_used;
  37 };
  38
  39 static struct mtd_info *mymtd;
  40
  41 static struct map_info nor_map = {
  42         name:           "adm8668-nor",
  43         size:           FLASH_SIZE,
  44         phys:           FLASH_PHYS_ADDR,
  45         bankwidth:      2,
  46 };
  47
  48 static struct mtd_partition nor_parts[] = {
  49         { name: "linux",  offset: 0x40000,  size: FLASH_SIZE - 0x40000, },
  50         { name: "rootfs", offset: 0x200000, size: 0x400000, },
  51         { name: NULL, },
  52 };
  53
  54 int __init init_mtd_partitions(struct mtd_info *mtd, size_t size)
  55 {
  56         int blocksize, off;
  57         size_t len;
  58         struct squashfs_super_block hdr;
  59
  60         blocksize = mtd->erasesize;
  61         if (blocksize < 0x10000)
  62                 blocksize = 0x10000;
  63
  64         memset(&hdr, 0xe5, sizeof(hdr));
  65         /* find and size squashfs */
  66         for (off = (128*1024); off < size; off += blocksize) {
  67                 if (mtd->read(mtd, off, sizeof(hdr), &len, (char *)&hdr) ||
  68                     len != sizeof(hdr))
  69                         continue;
  70
  71                 if (hdr.s_magic == SQUASHFS_MAGIC) {
  72                         printk(KERN_INFO "%s: Filesystem type: squashfs, off=%#x size=%#x\n",
  73                                 mtd->name, off, (unsigned int)hdr.bytes_used);
  74                         /* Update the squashfs start address only! */
  75                         nor_parts[1].offset = off;
  76                         nor_parts[1].size = FLASH_SIZE - off;
  77                         return 2;
  78                 }
  79         }
  80         return 2;
  81 }
  82
  83 int __init init_nor(void)
  84 {
  85         int nr_parts;
  86
  87         printk(KERN_NOTICE "ADM8668 NOR flash device: %#x at %#x\n",
  88                         FLASH_SIZE, FLASH_PHYS_ADDR);
  89
  90         nor_map.virt = ioremap(FLASH_PHYS_ADDR, FLASH_SIZE);
  91         if (!nor_map.virt) {
  92                 printk("Failed to ioremap\n");
  93                 return -EIO;
  94         }
  95
  96         simple_map_init(&nor_map);
  97         mymtd = do_map_probe("cfi_probe", &nor_map);
  98         if (!mymtd) {
  99                 iounmap((void *)nor_map.virt);
 100                 return -ENXIO;
 101         }
 102         mymtd->owner = THIS_MODULE;
 103         nr_parts = init_mtd_partitions(mymtd, mymtd->size);
 104         add_mtd_partitions(mymtd, nor_parts, nr_parts);
 105
 106         return 0;
 107 }
 108
 109 static void __exit cleanup_nor(void)
 110 {
 111         if (mymtd) {
 112                 del_mtd_partitions(mymtd);
 113                 map_destroy(mymtd);
 114         }
 115         if (nor_map.virt) {
 116                 iounmap((void *)nor_map.virt);
 117                 nor_map.virt = 0;
 118         }
 119 }
 120
 121 module_init(init_nor);
 122 module_exit(cleanup_nor);
 123
 124 MODULE_LICENSE("GPL");
 125 MODULE_AUTHOR("Scott Nicholas <neutronscott@scottn.us>");
 126 MODULE_DESCRIPTION("MTD map driver for ADM8668 NOR Flash");