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
  20 static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
  21 static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
  22 static 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
  27 module_param(total_size, ulong, 0);
  28 MODULE_PARM_DESC(total_size, "Total device size in KiB");
  29 module_param(erase_size, ulong, 0);
  30 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  31 module_param(writebuf_size, ulong, 0);
  32 MODULE_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..
  36 static struct mtd_info *mtd_info;
  37
  38 static 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
  57 static 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
  67 static 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
  75 static 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  */
  85 static 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
  93 static 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
 101 static 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
 109 static 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
 118 int 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
 147 static 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
 177 module_init(init_mtdram);
 178 module_exit(cleanup_mtdram);
 179
 180 MODULE_LICENSE("GPL");
 181 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 182 MODULE_DESCRIPTION("Simulated MTD driver for testing");