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
  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
  34// We could store these in the mtd structure, but we only support 1 device..
  35static struct mtd_info *mtd_info;
  36
  37static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  38{
  39        int ret = 0;
  40
  41        /* Start address must align on block boundary */
  42        if (mtd_mod_by_eb(ofs, mtd)) {
  43                pr_debug("%s: unaligned address\n", __func__);
  44                ret = -EINVAL;
  45        }
  46
  47        /* Length must align on block boundary */
  48        if (mtd_mod_by_eb(len, mtd)) {
  49                pr_debug("%s: length not block aligned\n", __func__);
  50                ret = -EINVAL;
  51        }
  52
  53        return ret;
  54}
  55
  56static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  57{
  58        if (check_offs_len(mtd, instr->addr, instr->len))
  59                return -EINVAL;
  60        memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  61
  62        return 0;
  63}
  64
  65static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  66                size_t *retlen, void **virt, resource_size_t *phys)
  67{
  68        *virt = mtd->priv + from;
  69        *retlen = len;
  70
  71        if (phys) {
  72                /* limit retlen to the number of contiguous physical pages */
  73                unsigned long page_ofs = offset_in_page(*virt);
  74                void *addr = *virt - page_ofs;
  75                unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
  76
  77                *phys = __pfn_to_phys(pfn0) + page_ofs;
  78                len += page_ofs;
  79                while (len > PAGE_SIZE) {
  80                        len -= PAGE_SIZE;
  81                        addr += PAGE_SIZE;
  82                        pfn0++;
  83                        pfn1 = vmalloc_to_pfn(addr);
  84                        if (pfn1 != pfn0) {
  85                                *retlen = addr - *virt;
  86                                break;
  87                        }
  88                }
  89        }
  90
  91        return 0;
  92}
  93
  94static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  95{
  96        return 0;
  97}
  98
  99static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
 100                size_t *retlen, u_char *buf)
 101{
 102        memcpy(buf, mtd->priv + from, len);
 103        *retlen = len;
 104        return 0;
 105}
 106
 107static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
 108                size_t *retlen, const u_char *buf)
 109{
 110        memcpy((char *)mtd->priv + to, buf, len);
 111        *retlen = len;
 112        return 0;
 113}
 114
 115static void __exit cleanup_mtdram(void)
 116{
 117        if (mtd_info) {
 118                mtd_device_unregister(mtd_info);
 119                vfree(mtd_info->priv);
 120                kfree(mtd_info);
 121        }
 122}
 123
 124int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 125                unsigned long size, const char *name)
 126{
 127        memset(mtd, 0, sizeof(*mtd));
 128
 129        /* Setup the MTD structure */
 130        mtd->name = name;
 131        mtd->type = MTD_RAM;
 132        mtd->flags = MTD_CAP_RAM;
 133        mtd->size = size;
 134        mtd->writesize = 1;
 135        mtd->writebufsize = writebuf_size;
 136        mtd->erasesize = MTDRAM_ERASE_SIZE;
 137        mtd->priv = mapped_address;
 138
 139        mtd->owner = THIS_MODULE;
 140        mtd->_erase = ram_erase;
 141        mtd->_point = ram_point;
 142        mtd->_unpoint = ram_unpoint;
 143        mtd->_read = ram_read;
 144        mtd->_write = ram_write;
 145
 146        if (mtd_device_register(mtd, NULL, 0))
 147                return -EIO;
 148
 149        return 0;
 150}
 151
 152static int __init init_mtdram(void)
 153{
 154        void *addr;
 155        int err;
 156
 157        if (!total_size)
 158                return -EINVAL;
 159
 160        /* Allocate some memory */
 161        mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 162        if (!mtd_info)
 163                return -ENOMEM;
 164
 165        addr = vmalloc(MTDRAM_TOTAL_SIZE);
 166        if (!addr) {
 167                kfree(mtd_info);
 168                mtd_info = NULL;
 169                return -ENOMEM;
 170        }
 171        err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 172        if (err) {
 173                vfree(addr);
 174                kfree(mtd_info);
 175                mtd_info = NULL;
 176                return err;
 177        }
 178        memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 179        return err;
 180}
 181
 182module_init(init_mtdram);
 183module_exit(cleanup_mtdram);
 184
 185MODULE_LICENSE("GPL");
 186MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 187MODULE_DESCRIPTION("Simulated MTD driver for testing");
 188