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