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
  21 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
  22 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
  23 static 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
  28 module_param(total_size, ulong, 0);
  29 MODULE_PARM_DESC(total_size, "Total device size in KiB");
  30 module_param(erase_size, ulong, 0);
  31 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  32 module_param(writebuf_size, ulong, 0);
  33 MODULE_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..
  37 static struct mtd_info *mtd_info;
  38
  39 static 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
  58 static 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         instr->state = MTD_ERASE_DONE;
  64         mtd_erase_callback(instr);
  65         return 0;
  66 }
  67
  68 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  69                 size_t *retlen, void **virt, resource_size_t *phys)
  70 {
  71         *virt = mtd->priv + from;
  72         *retlen = len;
  73
  74         if (phys) {
  75                 /* limit retlen to the number of contiguous physical pages */
  76                 unsigned long page_ofs = offset_in_page(*virt);
  77                 void *addr = *virt - page_ofs;
  78                 unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
  79
  80                 *phys = __pfn_to_phys(pfn0) + page_ofs;
  81                 len += page_ofs;
  82                 while (len > PAGE_SIZE) {
  83                         len -= PAGE_SIZE;
  84                         addr += PAGE_SIZE;
  85                         pfn0++;
  86                         pfn1 = vmalloc_to_pfn(addr);
  87                         if (pfn1 != pfn0) {
  88                                 *retlen = addr - *virt;
  89                                 break;
  90                         }
  91                 }
  92         }
  93
  94         return 0;
  95 }
  96
  97 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  98 {
  99         return 0;
 100 }
 101
 102 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
 103                 size_t *retlen, u_char *buf)
 104 {
 105         memcpy(buf, mtd->priv + from, len);
 106         *retlen = len;
 107         return 0;
 108 }
 109
 110 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
 111                 size_t *retlen, const u_char *buf)
 112 {
 113         memcpy((char *)mtd->priv + to, buf, len);
 114         *retlen = len;
 115         return 0;
 116 }
 117
 118 static void __exit cleanup_mtdram(void)
 119 {
 120         if (mtd_info) {
 121                 mtd_device_unregister(mtd_info);
 122                 vfree(mtd_info->priv);
 123                 kfree(mtd_info);
 124         }
 125 }
 126
 127 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 128                 unsigned long size, const char *name)
 129 {
 130         memset(mtd, 0, sizeof(*mtd));
 131
 132         /* Setup the MTD structure */
 133         mtd->name = name;
 134         mtd->type = MTD_RAM;
 135         mtd->flags = MTD_CAP_RAM;
 136         mtd->size = size;
 137         mtd->writesize = 1;
 138         mtd->writebufsize = writebuf_size;
 139         mtd->erasesize = MTDRAM_ERASE_SIZE;
 140         mtd->priv = mapped_address;
 141
 142         mtd->owner = THIS_MODULE;
 143         mtd->_erase = ram_erase;
 144         mtd->_point = ram_point;
 145         mtd->_unpoint = ram_unpoint;
 146         mtd->_read = ram_read;
 147         mtd->_write = ram_write;
 148
 149         if (mtd_device_register(mtd, NULL, 0))
 150                 return -EIO;
 151
 152         return 0;
 153 }
 154
 155 static int __init init_mtdram(void)
 156 {
 157         void *addr;
 158         int err;
 159
 160         if (!total_size)
 161                 return -EINVAL;
 162
 163         /* Allocate some memory */
 164         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 165         if (!mtd_info)
 166                 return -ENOMEM;
 167
 168         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 169         if (!addr) {
 170                 kfree(mtd_info);
 171                 mtd_info = NULL;
 172                 return -ENOMEM;
 173         }
 174         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 175         if (err) {
 176                 vfree(addr);
 177                 kfree(mtd_info);
 178                 mtd_info = NULL;
 179                 return err;
 180         }
 181         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 182         return err;
 183 }
 184
 185 module_init(init_mtdram);
 186 module_exit(cleanup_mtdram);
 187
 188 MODULE_LICENSE("GPL");
 189 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 190 MODULE_DESCRIPTION("Simulated MTD driver for testing");