drivers/mtd/mtdram.c

   1 /*
   2  * mtdram - a test mtd device
   3  * $Id: mtdram.c,v 1.13 2000/07/03 10:01:38 dwmw2 Exp $
   4  * Author: Alexander Larsson <alex@cendio.se>
   5  *
   6  * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
   7  *
   8  * This code is GPL
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13
  14 #include <linux/malloc.h>
  15 #include <linux/ioport.h>
  16 #include <linux/mtd/compatmac.h>
  17 #include <linux/mtd/mtd.h>
  18
  19
  20 #define MTDRAM_TOTAL_SIZE 1024*1024*8
  21 #define MTDRAM_ERASE_SIZE 4*1024
  22
  23
  24 // We could store these in the mtd structure, but we only support 1 device..
  25 static struct mtd_info *mtd_info;
  26
  27
  28 static int
  29 ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  30 {
  31   if (instr->addr + instr->len > mtd->size)
  32     return -EINVAL;
  33
  34   memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  35
  36   instr->state = MTD_ERASE_DONE;
  37
  38   if (instr->callback)
  39     (*(instr->callback))(instr);
  40   return 0;
  41 }
  42
  43 static int ram_point (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf)
  44 {
  45   if (from + len > mtd->size)
  46     return -EINVAL;
  47
  48   *mtdbuf = mtd->priv + from;
  49   *retlen = len;
  50   return 0;
  51 }
  52
  53 static void ram_unpoint (struct mtd_info *mtd, u_char *addr)
  54 {
  55 }
  56
  57 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  58              size_t *retlen, u_char *buf)
  59 {
  60   if (from + len > mtd->size)
  61     return -EINVAL;
  62
  63   memcpy(buf, mtd->priv + from, len);
  64
  65   *retlen=len;
  66   return 0;
  67 }
  68
  69 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  70               size_t *retlen, const u_char *buf)
  71 {
  72   if (to + len > mtd->size)
  73     return -EINVAL;
  74
  75   memcpy ((char *)mtd->priv + to, buf, len);
  76
  77   *retlen=len;
  78   return 0;
  79 }
  80
  81 #if LINUX_VERSION_CODE < 0x20300
  82 #ifdef MODULE
  83 #define init_mtdram init_module
  84 #define cleanup_mtdram cleanup_module
  85 #endif
  86 #endif
  87
  88 //static void __exit cleanup_mtdram(void)
  89 mod_exit_t cleanup_mtdram(void)
  90 {
  91   if (mtd_info) {
  92     del_mtd_device(mtd_info);
  93     if (mtd_info->priv)
  94       vfree(mtd_info->priv);
  95     kfree(mtd_info);
  96   }
  97 }
  98
  99 extern struct module __this_module;
 100
 101 mod_init_t init_mtdram(void)
 102 {
 103    // Allocate some memory
 104    mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 105    if (mtd_info == 0)
 106       return 0;
 107
 108    memset(mtd_info, 0, sizeof(*mtd_info));
 109
 110    // Setup the MTD structure
 111    mtd_info->name = "mtdram test device";
 112    mtd_info->type = MTD_RAM;
 113    mtd_info->flags = MTD_CAP_RAM;
 114    mtd_info->size = MTDRAM_TOTAL_SIZE;
 115    mtd_info->erasesize = MTDRAM_ERASE_SIZE;
 116    mtd_info->priv = vmalloc(MTDRAM_TOTAL_SIZE);
 117    memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 118
 119 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
 120    mtd_info->module = THIS_MODULE;
 121 #endif
 122
 123    if (!mtd_info->priv) {
 124      kfree(mtd_info);
 125      mtd_info = NULL;
 126      return -ENOMEM;
 127    }
 128    mtd_info->erase = ram_erase;
 129    mtd_info->point = ram_point;
 130    mtd_info->unpoint = ram_unpoint;
 131    mtd_info->read = ram_read;
 132    mtd_info->write = ram_write;
 133
 134    if (add_mtd_device(mtd_info)) {
 135      vfree(mtd_info->priv);
 136      kfree(mtd_info);
 137      mtd_info = NULL;
 138      return -EIO;
 139    }
 140
 141    return 0;
 142 }
 143
 144 #if LINUX_VERSION_CODE > 0x20300
 145 module_init(init_mtdram);
 146 module_exit(cleanup_mtdram);
 147 #endif