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/mm.h>
  17#include <linux/init.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;
  23static unsigned long writebuf_size = 64;
  24#define MTDRAM_TOTAL_SIZE (total_size * 1024)
  25#define MTDRAM_ERASE_SIZE (erase_size * 1024)
  26
  27#ifdef MODULE
  28module_param(total_size, ulong, 0);
  29MODULE_PARM_DESC(total_size, "Total device size in KiB");
  30module_param(erase_size, ulong, 0);
  31MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  32module_param(writebuf_size, ulong, 0);
  33MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)");
  34#endif
  35
  36// We could store these in the mtd structure, but we only support 1 device..
  37static struct mtd_info *mtd_info;
  38
  39static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  40{
  41        int ret = 0;
  42
  43        /* Start address must align on block boundary */
  44        if (mtd_mod_by_eb(ofs, mtd)) {
  45                pr_debug("%s: unaligned address\n", __func__);
  46                ret = -EINVAL;
  47        }
  48
  49        /* Length must align on block boundary */
  50        if (mtd_mod_by_eb(len, mtd)) {
  51                pr_debug("%s: length not block aligned\n", __func__);
  52                ret = -EINVAL;
  53        }
  54
  55        return ret;
  56}
  57
  58static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  59{
  60        if (check_offs_len(mtd, instr->addr, instr->len))
  61                return -EINVAL;
  62        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  63
  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
  73        if (phys) {
  74                /* limit retlen to the number of contiguous physical pages */
  75                unsigned long page_ofs = offset_in_page(*virt);
  76                void *addr = *virt - page_ofs;
  77                unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
  78
  79                *phys = __pfn_to_phys(pfn0) + page_ofs;
  80                len += page_ofs;
  81                while (len > PAGE_SIZE) {
  82                        len -= PAGE_SIZE;
  83                        addr += PAGE_SIZE;
  84                        pfn0++;
  85                        pfn1 = vmalloc_to_pfn(addr);
  86                        if (pfn1 != pfn0) {
  87                                *retlen = addr - *virt;
  88                                break;
  89                        }
  90                }
  91        }
  92
  93        return 0;
  94}
  95
  96static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  97{
  98        return 0;
  99}
 100
 101static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
 102                size_t *retlen, u_char *buf)
 103{
 104        memcpy(buf, mtd->priv + from, len);
 105        *retlen = len;
 106        return 0;
 107}
 108
 109static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
 110                size_t *retlen, const u_char *buf)
 111{
 112        memcpy((char *)mtd->priv + to, buf, len);
 113        *retlen = len;
 114        return 0;
 115}
 116
 117static void __exit cleanup_mtdram(void)
 118{
 119        if (mtd_info) {
 120                mtd_device_unregister(mtd_info);
 121                vfree(mtd_info->priv);
 122                kfree(mtd_info);
 123        }
 124}
 125
 126int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 127                unsigned long size, const char *name)
 128{
 129        memset(mtd, 0, sizeof(*mtd));
 130
 131        /* Setup the MTD structure */
 132        mtd->name = name;
 133        mtd->type = MTD_RAM;
 134        mtd->flags = MTD_CAP_RAM;
 135        mtd->size = size;
 136        mtd->writesize = 1;
 137        mtd->writebufsize = writebuf_size;
 138        mtd->erasesize = MTDRAM_ERASE_SIZE;
 139        mtd->priv = mapped_address;
 140
 141        mtd->owner = THIS_MODULE;
 142        mtd->_erase = ram_erase;
 143        mtd->_point = ram_point;
 144        mtd->_unpoint = ram_unpoint;
 145        mtd->_read = ram_read;
 146        mtd->_write = ram_write;
 147
 148        if (mtd_device_register(mtd, NULL, 0))
 149                return -EIO;
 150
 151        return 0;
 152}
 153
 154static int __init init_mtdram(void)
 155{
 156        void *addr;
 157        int err;
 158
 159        if (!total_size)
 160                return -EINVAL;
 161
 162        /* Allocate some memory */
 163        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 164        if (!mtd_info)
 165                return -ENOMEM;
 166
 167        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 168        if (!addr) {
 169                kfree(mtd_info);
 170                mtd_info = NULL;
 171                return -ENOMEM;
 172        }
 173        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 174        if (err) {
 175                vfree(addr);
 176                kfree(mtd_info);
 177                mtd_info = NULL;
 178                return err;
 179        }
 180        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 181        return err;
 182}
 183
 184module_init(init_mtdram);
 185module_exit(cleanup_mtdram);
 186
 187MODULE_LICENSE("GPL");
 188MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 189MODULE_DESCRIPTION("Simulated MTD driver for testing");
 190