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 check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  36{
  37        int ret = 0;
  38
  39        /* Start address must align on block boundary */
  40        if (mtd_mod_by_eb(ofs, mtd)) {
  41                pr_debug("%s: unaligned address\n", __func__);
  42                ret = -EINVAL;
  43        }
  44
  45        /* Length must align on block boundary */
  46        if (mtd_mod_by_eb(len, mtd)) {
  47                pr_debug("%s: length not block aligned\n", __func__);
  48                ret = -EINVAL;
  49        }
  50
  51        return ret;
  52}
  53
  54static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  55{
  56        if (check_offs_len(mtd, instr->addr, instr->len))
  57                return -EINVAL;
  58        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  59        instr->state = MTD_ERASE_DONE;
  60        mtd_erase_callback(instr);
  61        return 0;
  62}
  63
  64static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  65                size_t *retlen, void **virt, resource_size_t *phys)
  66{
  67        *virt = mtd->priv + from;
  68        *retlen = len;
  69        return 0;
  70}
  71
  72static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  73{
  74        return 0;
  75}
  76
  77/*
  78 * Allow NOMMU mmap() to directly map the device (if not NULL)
  79 * - return the address to which the offset maps
  80 * - return -ENOSYS to indicate refusal to do the mapping
  81 */
  82static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  83                                           unsigned long len,
  84                                           unsigned long offset,
  85                                           unsigned long flags)
  86{
  87        return (unsigned long) mtd->priv + offset;
  88}
  89
  90static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  91                size_t *retlen, u_char *buf)
  92{
  93        memcpy(buf, mtd->priv + from, len);
  94        *retlen = len;
  95        return 0;
  96}
  97
  98static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  99                size_t *retlen, const u_char *buf)
 100{
 101        memcpy((char *)mtd->priv + to, buf, len);
 102        *retlen = len;
 103        return 0;
 104}
 105
 106static void __exit cleanup_mtdram(void)
 107{
 108        if (mtd_info) {
 109                mtd_device_unregister(mtd_info);
 110                vfree(mtd_info->priv);
 111                kfree(mtd_info);
 112        }
 113}
 114
 115int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 116                unsigned long size, const char *name)
 117{
 118        memset(mtd, 0, sizeof(*mtd));
 119
 120        /* Setup the MTD structure */
 121        mtd->name = name;
 122        mtd->type = MTD_RAM;
 123        mtd->flags = MTD_CAP_RAM;
 124        mtd->size = size;
 125        mtd->writesize = 1;
 126        mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
 127        mtd->erasesize = MTDRAM_ERASE_SIZE;
 128        mtd->priv = mapped_address;
 129
 130        mtd->owner = THIS_MODULE;
 131        mtd->_erase = ram_erase;
 132        mtd->_point = ram_point;
 133        mtd->_unpoint = ram_unpoint;
 134        mtd->_get_unmapped_area = ram_get_unmapped_area;
 135        mtd->_read = ram_read;
 136        mtd->_write = ram_write;
 137
 138        if (mtd_device_register(mtd, NULL, 0))
 139                return -EIO;
 140
 141        return 0;
 142}
 143
 144static int __init init_mtdram(void)
 145{
 146        void *addr;
 147        int err;
 148
 149        if (!total_size)
 150                return -EINVAL;
 151
 152        /* Allocate some memory */
 153        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 154        if (!mtd_info)
 155                return -ENOMEM;
 156
 157        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 158        if (!addr) {
 159                kfree(mtd_info);
 160                mtd_info = NULL;
 161                return -ENOMEM;
 162        }
 163        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 164        if (err) {
 165                vfree(addr);
 166                kfree(mtd_info);
 167                mtd_info = NULL;
 168                return err;
 169        }
 170        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 171        return err;
 172}
 173
 174module_init(init_mtdram);
 175module_exit(cleanup_mtdram);
 176
 177MODULE_LICENSE("GPL");
 178MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 179MODULE_DESCRIPTION("Simulated MTD driver for testing");
 180