linux/drivers/mtd/devices/mtdram.c
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   1/*
   2 * mtdram - a test mtd device
   3 * Author: Alexander Larsson <alex@cendio.se>
   4 *
   5 * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
   6 * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de>
   7 *
   8 * This code is GPL
   9 *
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/ioport.h>
  15#include <linux/vmalloc.h>
  16#include <linux/init.h>
  17#include <linux/mtd/compatmac.h>
  18#include <linux/mtd/mtd.h>
  19#include <linux/mtd/mtdram.h>
  20
  21static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
  22static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
  23#define MTDRAM_TOTAL_SIZE (total_size * 1024)
  24#define MTDRAM_ERASE_SIZE (erase_size * 1024)
  25
  26#ifdef MODULE
  27module_param(total_size, ulong, 0);
  28MODULE_PARM_DESC(total_size, "Total device size in KiB");
  29module_param(erase_size, ulong, 0);
  30MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  31#endif
  32
  33// We could store these in the mtd structure, but we only support 1 device..
  34static struct mtd_info *mtd_info;
  35
  36static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  37{
  38        if (instr->addr + instr->len > mtd->size)
  39                return -EINVAL;
  40
  41        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  42
  43        instr->state = MTD_ERASE_DONE;
  44        mtd_erase_callback(instr);
  45
  46        return 0;
  47}
  48
  49static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  50                size_t *retlen, void **virt, resource_size_t *phys)
  51{
  52        if (from + len > mtd->size)
  53                return -EINVAL;
  54
  55        /* can we return a physical address with this driver? */
  56        if (phys)
  57                return -EINVAL;
  58
  59        *virt = mtd->priv + from;
  60        *retlen = len;
  61        return 0;
  62}
  63
  64static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  65{
  66}
  67
  68static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  69                size_t *retlen, u_char *buf)
  70{
  71        if (from + len > mtd->size)
  72                return -EINVAL;
  73
  74        memcpy(buf, mtd->priv + from, len);
  75
  76        *retlen = len;
  77        return 0;
  78}
  79
  80static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  81                size_t *retlen, const u_char *buf)
  82{
  83        if (to + len > mtd->size)
  84                return -EINVAL;
  85
  86        memcpy((char *)mtd->priv + to, buf, len);
  87
  88        *retlen = len;
  89        return 0;
  90}
  91
  92static void __exit cleanup_mtdram(void)
  93{
  94        if (mtd_info) {
  95                del_mtd_device(mtd_info);
  96                vfree(mtd_info->priv);
  97                kfree(mtd_info);
  98        }
  99}
 100
 101int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 102                unsigned long size, char *name)
 103{
 104        memset(mtd, 0, sizeof(*mtd));
 105
 106        /* Setup the MTD structure */
 107        mtd->name = name;
 108        mtd->type = MTD_RAM;
 109        mtd->flags = MTD_CAP_RAM;
 110        mtd->size = size;
 111        mtd->writesize = 1;
 112        mtd->erasesize = MTDRAM_ERASE_SIZE;
 113        mtd->priv = mapped_address;
 114
 115        mtd->owner = THIS_MODULE;
 116        mtd->erase = ram_erase;
 117        mtd->point = ram_point;
 118        mtd->unpoint = ram_unpoint;
 119        mtd->read = ram_read;
 120        mtd->write = ram_write;
 121
 122        if (add_mtd_device(mtd)) {
 123                return -EIO;
 124        }
 125
 126        return 0;
 127}
 128
 129static int __init init_mtdram(void)
 130{
 131        void *addr;
 132        int err;
 133
 134        if (!total_size)
 135                return -EINVAL;
 136
 137        /* Allocate some memory */
 138        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 139        if (!mtd_info)
 140                return -ENOMEM;
 141
 142        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 143        if (!addr) {
 144                kfree(mtd_info);
 145                mtd_info = NULL;
 146                return -ENOMEM;
 147        }
 148        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 149        if (err) {
 150                vfree(addr);
 151                kfree(mtd_info);
 152                mtd_info = NULL;
 153                return err;
 154        }
 155        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 156        return err;
 157}
 158
 159module_init(init_mtdram);
 160module_exit(cleanup_mtdram);
 161
 162MODULE_LICENSE("GPL");
 163MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 164MODULE_DESCRIPTION("Simulated MTD driver for testing");
 165
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