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/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
  68/*
  69 * Allow NOMMU mmap() to directly map the device (if not NULL)
  70 * - return the address to which the offset maps
  71 * - return -ENOSYS to indicate refusal to do the mapping
  72 */
  73static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  74                                           unsigned long len,
  75                                           unsigned long offset,
  76                                           unsigned long flags)
  77{
  78        return (unsigned long) mtd->priv + offset;
  79}
  80
  81static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  82                size_t *retlen, u_char *buf)
  83{
  84        if (from + len > mtd->size)
  85                return -EINVAL;
  86
  87        memcpy(buf, mtd->priv + from, len);
  88
  89        *retlen = len;
  90        return 0;
  91}
  92
  93static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  94                size_t *retlen, const u_char *buf)
  95{
  96        if (to + len > mtd->size)
  97                return -EINVAL;
  98
  99        memcpy((char *)mtd->priv + to, buf, len);
 100
 101        *retlen = len;
 102        return 0;
 103}
 104
 105static void __exit cleanup_mtdram(void)
 106{
 107        if (mtd_info) {
 108                del_mtd_device(mtd_info);
 109                vfree(mtd_info->priv);
 110                kfree(mtd_info);
 111        }
 112}
 113
 114int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 115                unsigned long size, char *name)
 116{
 117        memset(mtd, 0, sizeof(*mtd));
 118
 119        /* Setup the MTD structure */
 120        mtd->name = name;
 121        mtd->type = MTD_RAM;
 122        mtd->flags = MTD_CAP_RAM;
 123        mtd->size = size;
 124        mtd->writesize = 1;
 125        mtd->erasesize = MTDRAM_ERASE_SIZE;
 126        mtd->priv = mapped_address;
 127
 128        mtd->owner = THIS_MODULE;
 129        mtd->erase = ram_erase;
 130        mtd->point = ram_point;
 131        mtd->unpoint = ram_unpoint;
 132        mtd->get_unmapped_area = ram_get_unmapped_area;
 133        mtd->read = ram_read;
 134        mtd->write = ram_write;
 135
 136        if (add_mtd_device(mtd)) {
 137                return -EIO;
 138        }
 139
 140        return 0;
 141}
 142
 143static int __init init_mtdram(void)
 144{
 145        void *addr;
 146        int err;
 147
 148        if (!total_size)
 149                return -EINVAL;
 150
 151        /* Allocate some memory */
 152        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 153        if (!mtd_info)
 154                return -ENOMEM;
 155
 156        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 157        if (!addr) {
 158                kfree(mtd_info);
 159                mtd_info = NULL;
 160                return -ENOMEM;
 161        }
 162        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 163        if (err) {
 164                vfree(addr);
 165                kfree(mtd_info);
 166                mtd_info = NULL;
 167                return err;
 168        }
 169        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 170        return err;
 171}
 172
 173module_init(init_mtdram);
 174module_exit(cleanup_mtdram);
 175
 176MODULE_LICENSE("GPL");
 177MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 178MODULE_DESCRIPTION("Simulated MTD driver for testing");
 179