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 #define MTDRAM_TOTAL_SIZE (total_size * 1024)
  23 #define MTDRAM_ERASE_SIZE (erase_size * 1024)
  24
  25 #ifdef MODULE
  26 module_param(total_size, ulong, 0);
  27 MODULE_PARM_DESC(total_size, "Total device size in KiB");
  28 module_param(erase_size, ulong, 0);
  29 MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
  30 #endif
  31
  32 // We could store these in the mtd structure, but we only support 1 device..
  33 static struct mtd_info *mtd_info;
  34
  35 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  36 {
  37         if (instr->addr + instr->len > mtd->size)
  38                 return -EINVAL;
  39
  40         memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  41
  42         instr->state = MTD_ERASE_DONE;
  43         mtd_erase_callback(instr);
  44
  45         return 0;
  46 }
  47
  48 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  49                 size_t *retlen, void **virt, resource_size_t *phys)
  50 {
  51         if (from + len > mtd->size)
  52                 return -EINVAL;
  53
  54         /* can we return a physical address with this driver? */
  55         if (phys)
  56                 return -EINVAL;
  57
  58         *virt = mtd->priv + from;
  59         *retlen = len;
  60         return 0;
  61 }
  62
  63 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  64 {
  65         return 0;
  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  */
  73 static 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
  81 static 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
  93 static 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
 105 static void __exit cleanup_mtdram(void)
 106 {
 107         if (mtd_info) {
 108                 mtd_device_unregister(mtd_info);
 109                 vfree(mtd_info->priv);
 110                 kfree(mtd_info);
 111         }
 112 }
 113
 114 int 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->writebufsize = 64; /* Mimic CFI NOR flashes */
 126         mtd->erasesize = MTDRAM_ERASE_SIZE;
 127         mtd->priv = mapped_address;
 128
 129         mtd->owner = THIS_MODULE;
 130         mtd->_erase = ram_erase;
 131         mtd->_point = ram_point;
 132         mtd->_unpoint = ram_unpoint;
 133         mtd->_get_unmapped_area = ram_get_unmapped_area;
 134         mtd->_read = ram_read;
 135         mtd->_write = ram_write;
 136
 137         if (mtd_device_register(mtd, NULL, 0))
 138                 return -EIO;
 139
 140         return 0;
 141 }
 142
 143 static 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
 173 module_init(init_mtdram);
 174 module_exit(cleanup_mtdram);
 175
 176 MODULE_LICENSE("GPL");
 177 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 178 MODULE_DESCRIPTION("Simulated MTD driver for testing");