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         memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  38         instr->state = MTD_ERASE_DONE;
  39         mtd_erase_callback(instr);
  40         return 0;
  41 }
  42
  43 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  44                 size_t *retlen, void **virt, resource_size_t *phys)
  45 {
  46         *virt = mtd->priv + from;
  47         *retlen = len;
  48         return 0;
  49 }
  50
  51 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  52 {
  53         return 0;
  54 }
  55
  56 /*
  57  * Allow NOMMU mmap() to directly map the device (if not NULL)
  58  * - return the address to which the offset maps
  59  * - return -ENOSYS to indicate refusal to do the mapping
  60  */
  61 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  62                                            unsigned long len,
  63                                            unsigned long offset,
  64                                            unsigned long flags)
  65 {
  66         return (unsigned long) mtd->priv + offset;
  67 }
  68
  69 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  70                 size_t *retlen, u_char *buf)
  71 {
  72         memcpy(buf, mtd->priv + from, len);
  73         *retlen = len;
  74         return 0;
  75 }
  76
  77 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  78                 size_t *retlen, const u_char *buf)
  79 {
  80         memcpy((char *)mtd->priv + to, buf, len);
  81         *retlen = len;
  82         return 0;
  83 }
  84
  85 static void __exit cleanup_mtdram(void)
  86 {
  87         if (mtd_info) {
  88                 mtd_device_unregister(mtd_info);
  89                 vfree(mtd_info->priv);
  90                 kfree(mtd_info);
  91         }
  92 }
  93
  94 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
  95                 unsigned long size, const char *name)
  96 {
  97         memset(mtd, 0, sizeof(*mtd));
  98
  99         /* Setup the MTD structure */
 100         mtd->name = name;
 101         mtd->type = MTD_RAM;
 102         mtd->flags = MTD_CAP_RAM;
 103         mtd->size = size;
 104         mtd->writesize = 1;
 105         mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
 106         mtd->erasesize = MTDRAM_ERASE_SIZE;
 107         mtd->priv = mapped_address;
 108
 109         mtd->owner = THIS_MODULE;
 110         mtd->_erase = ram_erase;
 111         mtd->_point = ram_point;
 112         mtd->_unpoint = ram_unpoint;
 113         mtd->_get_unmapped_area = ram_get_unmapped_area;
 114         mtd->_read = ram_read;
 115         mtd->_write = ram_write;
 116
 117         if (mtd_device_register(mtd, NULL, 0))
 118                 return -EIO;
 119
 120         return 0;
 121 }
 122
 123 static int __init init_mtdram(void)
 124 {
 125         void *addr;
 126         int err;
 127
 128         if (!total_size)
 129                 return -EINVAL;
 130
 131         /* Allocate some memory */
 132         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 133         if (!mtd_info)
 134                 return -ENOMEM;
 135
 136         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 137         if (!addr) {
 138                 kfree(mtd_info);
 139                 mtd_info = NULL;
 140                 return -ENOMEM;
 141         }
 142         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 143         if (err) {
 144                 vfree(addr);
 145                 kfree(mtd_info);
 146                 mtd_info = NULL;
 147                 return err;
 148         }
 149         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 150         return err;
 151 }
 152
 153 module_init(init_mtdram);
 154 module_exit(cleanup_mtdram);
 155
 156 MODULE_LICENSE("GPL");
 157 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 158 MODULE_DESCRIPTION("Simulated MTD driver for testing");