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        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  38        instr->state = MTD_ERASE_DONE;
  39        mtd_erase_callback(instr);
  40        return 0;
  41}
  42
  43static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  44                size_t *retlen, void **virt, resource_size_t *phys)
  45{
  46        *virt = mtd->priv + from;
  47        *retlen = len;
  48        return 0;
  49}
  50
  51static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  52{
  53        return 0;
  54}
  55
  56/*
  57 * Allow NOMMU mmap() to directly map the device (if not NULL)
  58 * - return the address to which the offset maps
  59 * - return -ENOSYS to indicate refusal to do the mapping
  60 */
  61static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  62                                           unsigned long len,
  63                                           unsigned long offset,
  64                                           unsigned long flags)
  65{
  66        return (unsigned long) mtd->priv + offset;
  67}
  68
  69static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  70                size_t *retlen, u_char *buf)
  71{
  72        memcpy(buf, mtd->priv + from, len);
  73        *retlen = len;
  74        return 0;
  75}
  76
  77static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  78                size_t *retlen, const u_char *buf)
  79{
  80        memcpy((char *)mtd->priv + to, buf, len);
  81        *retlen = len;
  82        return 0;
  83}
  84
  85static void __exit cleanup_mtdram(void)
  86{
  87        if (mtd_info) {
  88                mtd_device_unregister(mtd_info);
  89                vfree(mtd_info->priv);
  90                kfree(mtd_info);
  91        }
  92}
  93
  94int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
  95                unsigned long size, char *name)
  96{
  97        memset(mtd, 0, sizeof(*mtd));
  98
  99        /* Setup the MTD structure */
 100        mtd->name = name;
 101        mtd->type = MTD_RAM;
 102        mtd->flags = MTD_CAP_RAM;
 103        mtd->size = size;
 104        mtd->writesize = 1;
 105        mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
 106        mtd->erasesize = MTDRAM_ERASE_SIZE;
 107        mtd->priv = mapped_address;
 108
 109        mtd->owner = THIS_MODULE;
 110        mtd->_erase = ram_erase;
 111        mtd->_point = ram_point;
 112        mtd->_unpoint = ram_unpoint;
 113        mtd->_get_unmapped_area = ram_get_unmapped_area;
 114        mtd->_read = ram_read;
 115        mtd->_write = ram_write;
 116
 117        if (mtd_device_register(mtd, NULL, 0))
 118                return -EIO;
 119
 120        return 0;
 121}
 122
 123static int __init init_mtdram(void)
 124{
 125        void *addr;
 126        int err;
 127
 128        if (!total_size)
 129                return -EINVAL;
 130
 131        /* Allocate some memory */
 132        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 133        if (!mtd_info)
 134                return -ENOMEM;
 135
 136        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 137        if (!addr) {
 138                kfree(mtd_info);
 139                mtd_info = NULL;
 140                return -ENOMEM;
 141        }
 142        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 143        if (err) {
 144                vfree(addr);
 145                kfree(mtd_info);
 146                mtd_info = NULL;
 147                return err;
 148        }
 149        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 150        return err;
 151}
 152
 153module_init(init_mtdram);
 154module_exit(cleanup_mtdram);
 155
 156MODULE_LICENSE("GPL");
 157MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 158MODULE_DESCRIPTION("Simulated MTD driver for testing");
 159