drivers/mtd/devices/mtdram.c

   1 /*
   2  * mtdram - a test mtd device
   3  * $Id: mtdram.c,v 1.37 2005/04/21 03:42:11 joern Exp $
   4  * Author: Alexander Larsson <alex@cendio.se>
   5  *
   6  * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
   7  * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de>
   8  *
   9  * This code is GPL
  10  *
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/ioport.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/init.h>
  19 #include <linux/mtd/compatmac.h>
  20 #include <linux/mtd/mtd.h>
  21
  22 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
  23 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
  24 #define MTDRAM_TOTAL_SIZE (total_size * 1024)
  25 #define MTDRAM_ERASE_SIZE (erase_size * 1024)
  26
  27 #ifdef MODULE
  28 module_param(total_size, ulong, 0);
  29 MODULE_PARM_DESC(total_size, "Total device size in KiB");
  30 module_param(erase_size, ulong, 0);
  31 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  32 #endif
  33
  34 // We could store these in the mtd structure, but we only support 1 device..
  35 static struct mtd_info *mtd_info;
  36
  37 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  38 {
  39         if (instr->addr + instr->len > mtd->size)
  40                 return -EINVAL;
  41
  42         memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  43
  44         instr->state = MTD_ERASE_DONE;
  45         mtd_erase_callback(instr);
  46
  47         return 0;
  48 }
  49
  50 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  51                 size_t *retlen, u_char **mtdbuf)
  52 {
  53         if (from + len > mtd->size)
  54                 return -EINVAL;
  55
  56         *mtdbuf = mtd->priv + from;
  57         *retlen = len;
  58         return 0;
  59 }
  60
  61 static void ram_unpoint(struct mtd_info *mtd, u_char * addr, loff_t from,
  62                 size_t len)
  63 {
  64 }
  65
  66 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  67                 size_t *retlen, u_char *buf)
  68 {
  69         if (from + len > mtd->size)
  70                 return -EINVAL;
  71
  72         memcpy(buf, mtd->priv + from, len);
  73
  74         *retlen = len;
  75         return 0;
  76 }
  77
  78 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  79                 size_t *retlen, const u_char *buf)
  80 {
  81         if (to + len > mtd->size)
  82                 return -EINVAL;
  83
  84         memcpy((char *)mtd->priv + to, buf, len);
  85
  86         *retlen = len;
  87         return 0;
  88 }
  89
  90 static void __exit cleanup_mtdram(void)
  91 {
  92         if (mtd_info) {
  93                 del_mtd_device(mtd_info);
  94                 if (mtd_info->priv)
  95                         vfree(mtd_info->priv);
  96                 kfree(mtd_info);
  97         }
  98 }
  99
 100 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 101                 unsigned long size, char *name)
 102 {
 103         memset(mtd, 0, sizeof(*mtd));
 104
 105         /* Setup the MTD structure */
 106         mtd->name = name;
 107         mtd->type = MTD_RAM;
 108         mtd->flags = MTD_CAP_RAM;
 109         mtd->size = size;
 110         mtd->erasesize = MTDRAM_ERASE_SIZE;
 111         mtd->priv = mapped_address;
 112
 113         mtd->owner = THIS_MODULE;
 114         mtd->erase = ram_erase;
 115         mtd->point = ram_point;
 116         mtd->unpoint = ram_unpoint;
 117         mtd->read = ram_read;
 118         mtd->write = ram_write;
 119
 120         if (add_mtd_device(mtd)) {
 121                 return -EIO;
 122         }
 123
 124         return 0;
 125 }
 126
 127 static int __init init_mtdram(void)
 128 {
 129         void *addr;
 130         int err;
 131
 132         if (!total_size)
 133                 return -EINVAL;
 134
 135         /* Allocate some memory */
 136         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 137         if (!mtd_info)
 138                 return -ENOMEM;
 139
 140         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 141         if (!addr) {
 142                 kfree(mtd_info);
 143                 mtd_info = NULL;
 144                 return -ENOMEM;
 145         }
 146         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 147         if (err) {
 148                 vfree(addr);
 149                 kfree(mtd_info);
 150                 mtd_info = NULL;
 151                 return err;
 152         }
 153         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 154         return err;
 155 }
 156
 157 module_init(init_mtdram);
 158 module_exit(cleanup_mtdram);
 159
 160 MODULE_LICENSE("GPL");
 161 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 162 MODULE_DESCRIPTION("Simulated MTD driver for testing");