drivers/mtd/maps/uclinux.c

   1 /****************************************************************************/
   2
   3 /*
   4  *      uclinux.c -- generic memory mapped MTD driver for uclinux
   5  *
   6  *      (C) Copyright 2002, Greg Ungerer (gerg@snapgear.com)
   7  */
   8
   9 /****************************************************************************/
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/fs.h>
  16 #include <linux/mm.h>
  17 #include <linux/major.h>
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/map.h>
  20 #include <linux/mtd/partitions.h>
  21 #include <asm/io.h>
  22 #include <asm/sections.h>
  23
  24 /****************************************************************************/
  25
  26 #ifdef CONFIG_MTD_ROM
  27 #define MAP_NAME "rom"
  28 #else
  29 #define MAP_NAME "ram"
  30 #endif
  31
  32 /*
  33  * Blackfin uses uclinux_ram_map during startup, so it must not be static.
  34  * Provide a dummy declaration to make sparse happy.
  35  */
  36 extern struct map_info uclinux_ram_map;
  37
  38 struct map_info uclinux_ram_map = {
  39         .name = MAP_NAME,
  40         .size = 0,
  41 };
  42
  43 static unsigned long physaddr = -1;
  44 module_param(physaddr, ulong, S_IRUGO);
  45
  46 static struct mtd_info *uclinux_ram_mtdinfo;
  47
  48 /****************************************************************************/
  49
  50 static struct mtd_partition uclinux_romfs[] = {
  51         { .name = "ROMfs" }
  52 };
  53
  54 #define NUM_PARTITIONS  ARRAY_SIZE(uclinux_romfs)
  55
  56 /****************************************************************************/
  57
  58 static int uclinux_point(struct mtd_info *mtd, loff_t from, size_t len,
  59         size_t *retlen, void **virt, resource_size_t *phys)
  60 {
  61         struct map_info *map = mtd->priv;
  62         *virt = map->virt + from;
  63         if (phys)
  64                 *phys = map->phys + from;
  65         *retlen = len;
  66         return(0);
  67 }
  68
  69 /****************************************************************************/
  70
  71 static int __init uclinux_mtd_init(void)
  72 {
  73         struct mtd_info *mtd;
  74         struct map_info *mapp;
  75
  76         mapp = &uclinux_ram_map;
  77
  78         if (physaddr == -1)
  79                 mapp->phys = (resource_size_t)__bss_stop;
  80         else
  81                 mapp->phys = physaddr;
  82
  83         if (!mapp->size)
  84                 mapp->size = PAGE_ALIGN(ntohl(*((unsigned long *)(mapp->phys + 8))));
  85         mapp->bankwidth = 4;
  86
  87         printk("uclinux[mtd]: probe address=0x%x size=0x%x\n",
  88                 (int) mapp->phys, (int) mapp->size);
  89
  90         /*
  91          * The filesystem is guaranteed to be in direct mapped memory. It is
  92          * directly following the kernels own bss region. Following the same
  93          * mechanism used by architectures setting up traditional initrds we
  94          * use phys_to_virt to get the virtual address of its start.
  95          */
  96         mapp->virt = phys_to_virt(mapp->phys);
  97
  98         if (mapp->virt == 0) {
  99                 printk("uclinux[mtd]: no virtual mapping?\n");
 100                 return(-EIO);
 101         }
 102
 103         simple_map_init(mapp);
 104
 105         mtd = do_map_probe("map_" MAP_NAME, mapp);
 106         if (!mtd) {
 107                 printk("uclinux[mtd]: failed to find a mapping?\n");
 108                 return(-ENXIO);
 109         }
 110
 111         mtd->owner = THIS_MODULE;
 112         mtd->_point = uclinux_point;
 113         mtd->priv = mapp;
 114
 115         uclinux_ram_mtdinfo = mtd;
 116         mtd_device_register(mtd, uclinux_romfs, NUM_PARTITIONS);
 117
 118         return(0);
 119 }
 120
 121 /****************************************************************************/
 122
 123 static void __exit uclinux_mtd_cleanup(void)
 124 {
 125         if (uclinux_ram_mtdinfo) {
 126                 mtd_device_unregister(uclinux_ram_mtdinfo);
 127                 map_destroy(uclinux_ram_mtdinfo);
 128                 uclinux_ram_mtdinfo = NULL;
 129         }
 130         if (uclinux_ram_map.virt)
 131                 uclinux_ram_map.virt = 0;
 132 }
 133
 134 /****************************************************************************/
 135
 136 module_init(uclinux_mtd_init);
 137 module_exit(uclinux_mtd_cleanup);
 138
 139 MODULE_LICENSE("GPL");
 140 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>");
 141 MODULE_DESCRIPTION("Generic MTD for uClinux");
 142
 143 /****************************************************************************/