LXR linux/drivers/mtd/devices/mtdram.c

   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/mtd.h>
  18#include <linux/mtd/mtdram.h>
  19
  20static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
  21static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
  22#define MTDRAM_TOTAL_SIZE (total_size * 1024)
  23#define MTDRAM_ERASE_SIZE (erase_size * 1024)
  24
  25#ifdef MODULE
  26module_param(total_size, ulong, 0);
  27MODULE_PARM_DESC(total_size, "Total device size in KiB");
  28module_param(erase_size, ulong, 0);
  29MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  30#endif
  31
  32// We could store these in the mtd structure, but we only support 1 device..
  33static struct mtd_info *mtd_info;
  34
  35static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  36{
  37        if (instr->addr + instr->len > mtd->size)
  38                return -EINVAL;
  39
  40        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  41
  42        instr->state = MTD_ERASE_DONE;
  43        mtd_erase_callback(instr);
  44
  45        return 0;
  46}
  47
  48static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  49                size_t *retlen, void **virt, resource_size_t *phys)
  50{
  51        if (from + len > mtd->size)
  52                return -EINVAL;
  53
  54        /* can we return a physical address with this driver? */
  55        if (phys)
  56                return -EINVAL;
  57
  58        *virt = mtd->priv + from;
  59        *retlen = len;
  60        return 0;
  61}
  62
  63static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  64{
  65}
  66
  67/*
  68 * Allow NOMMU mmap() to directly map the device (if not NULL)
  69 * - return the address to which the offset maps
  70 * - return -ENOSYS to indicate refusal to do the mapping
  71 */
  72static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  73                                           unsigned long len,
  74                                           unsigned long offset,
  75                                           unsigned long flags)
  76{
  77        return (unsigned long) mtd->priv + offset;
  78}
  79
  80static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  81                size_t *retlen, u_char *buf)
  82{
  83        if (from + len > mtd->size)
  84                return -EINVAL;
  85
  86        memcpy(buf, mtd->priv + from, len);
  87
  88        *retlen = len;
  89        return 0;
  90}
  91
  92static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  93                size_t *retlen, const u_char *buf)
  94{
  95        if (to + len > mtd->size)
  96                return -EINVAL;
  97
  98        memcpy((char *)mtd->priv + to, buf, len);
  99
 100        *retlen = len;
 101        return 0;
 102}
 103
 104static void __exit cleanup_mtdram(void)
 105{
 106        if (mtd_info) {
 107                del_mtd_device(mtd_info);
 108                vfree(mtd_info->priv);
 109                kfree(mtd_info);
 110        }
 111}
 112
 113int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 114                unsigned long size, char *name)
 115{
 116        memset(mtd, 0, sizeof(*mtd));
 117
 118        /* Setup the MTD structure */
 119        mtd->name = name;
 120        mtd->type = MTD_RAM;
 121        mtd->flags = MTD_CAP_RAM;
 122        mtd->size = size;
 123        mtd->writesize = 1;
 124        mtd->erasesize = MTDRAM_ERASE_SIZE;
 125        mtd->priv = mapped_address;
 126
 127        mtd->owner = THIS_MODULE;
 128        mtd->erase = ram_erase;
 129        mtd->point = ram_point;
 130        mtd->unpoint = ram_unpoint;
 131        mtd->get_unmapped_area = ram_get_unmapped_area;
 132        mtd->read = ram_read;
 133        mtd->write = ram_write;
 134
 135        if (add_mtd_device(mtd)) {
 136                return -EIO;
 137        }
 138
 139        return 0;
 140}
 141
 142static int __init init_mtdram(void)
 143{
 144        void *addr;
 145        int err;
 146
 147        if (!total_size)
 148                return -EINVAL;
 149
 150        /* Allocate some memory */
 151        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 152        if (!mtd_info)
 153                return -ENOMEM;
 154
 155        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 156        if (!addr) {
 157                kfree(mtd_info);
 158                mtd_info = NULL;
 159                return -ENOMEM;
 160        }
 161        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 162        if (err) {
 163                vfree(addr);
 164                kfree(mtd_info);
 165                mtd_info = NULL;
 166                return err;
 167        }
 168        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 169        return err;
 170}
 171
 172module_init(init_mtdram);
 173module_exit(cleanup_mtdram);
 174
 175MODULE_LICENSE("GPL");
 176MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 177MODULE_DESCRIPTION("Simulated MTD driver for testing");
 178