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;
  22static unsigned long writebuf_size = 64;
  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");
  31module_param(writebuf_size, ulong, 0);
  32MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)");
  33#endif
  34
  35// We could store these in the mtd structure, but we only support 1 device..
  36static struct mtd_info *mtd_info;
  37
  38static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  39{
  40        int ret = 0;
  41
  42        /* Start address must align on block boundary */
  43        if (mtd_mod_by_eb(ofs, mtd)) {
  44                pr_debug("%s: unaligned address\n", __func__);
  45                ret = -EINVAL;
  46        }
  47
  48        /* Length must align on block boundary */
  49        if (mtd_mod_by_eb(len, mtd)) {
  50                pr_debug("%s: length not block aligned\n", __func__);
  51                ret = -EINVAL;
  52        }
  53
  54        return ret;
  55}
  56
  57static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  58{
  59        if (check_offs_len(mtd, instr->addr, instr->len))
  60                return -EINVAL;
  61        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  62        instr->state = MTD_ERASE_DONE;
  63        mtd_erase_callback(instr);
  64        return 0;
  65}
  66
  67static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  68                size_t *retlen, void **virt, resource_size_t *phys)
  69{
  70        *virt = mtd->priv + from;
  71        *retlen = len;
  72        return 0;
  73}
  74
  75static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  76{
  77        return 0;
  78}
  79
  80/*
  81 * Allow NOMMU mmap() to directly map the device (if not NULL)
  82 * - return the address to which the offset maps
  83 * - return -ENOSYS to indicate refusal to do the mapping
  84 */
  85static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  86                                           unsigned long len,
  87                                           unsigned long offset,
  88                                           unsigned long flags)
  89{
  90        return (unsigned long) mtd->priv + offset;
  91}
  92
  93static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  94                size_t *retlen, u_char *buf)
  95{
  96        memcpy(buf, mtd->priv + from, len);
  97        *retlen = len;
  98        return 0;
  99}
 100
 101static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
 102                size_t *retlen, const u_char *buf)
 103{
 104        memcpy((char *)mtd->priv + to, buf, len);
 105        *retlen = len;
 106        return 0;
 107}
 108
 109static void __exit cleanup_mtdram(void)
 110{
 111        if (mtd_info) {
 112                mtd_device_unregister(mtd_info);
 113                vfree(mtd_info->priv);
 114                kfree(mtd_info);
 115        }
 116}
 117
 118int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 119                unsigned long size, const char *name)
 120{
 121        memset(mtd, 0, sizeof(*mtd));
 122
 123        /* Setup the MTD structure */
 124        mtd->name = name;
 125        mtd->type = MTD_RAM;
 126        mtd->flags = MTD_CAP_RAM;
 127        mtd->size = size;
 128        mtd->writesize = 1;
 129        mtd->writebufsize = writebuf_size;
 130        mtd->erasesize = MTDRAM_ERASE_SIZE;
 131        mtd->priv = mapped_address;
 132
 133        mtd->owner = THIS_MODULE;
 134        mtd->_erase = ram_erase;
 135        mtd->_point = ram_point;
 136        mtd->_unpoint = ram_unpoint;
 137        mtd->_get_unmapped_area = ram_get_unmapped_area;
 138        mtd->_read = ram_read;
 139        mtd->_write = ram_write;
 140
 141        if (mtd_device_register(mtd, NULL, 0))
 142                return -EIO;
 143
 144        return 0;
 145}
 146
 147static int __init init_mtdram(void)
 148{
 149        void *addr;
 150        int err;
 151
 152        if (!total_size)
 153                return -EINVAL;
 154
 155        /* Allocate some memory */
 156        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 157        if (!mtd_info)
 158                return -ENOMEM;
 159
 160        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 161        if (!addr) {
 162                kfree(mtd_info);
 163                mtd_info = NULL;
 164                return -ENOMEM;
 165        }
 166        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 167        if (err) {
 168                vfree(addr);
 169                kfree(mtd_info);
 170                mtd_info = NULL;
 171                return err;
 172        }
 173        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 174        return err;
 175}
 176
 177module_init(init_mtdram);
 178module_exit(cleanup_mtdram);
 179
 180MODULE_LICENSE("GPL");
 181MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 182MODULE_DESCRIPTION("Simulated MTD driver for testing");
 183