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/compatmac.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 #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 #endif
  32
  33 // We could store these in the mtd structure, but we only support 1 device..
  34 static struct mtd_info *mtd_info;
  35
  36 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  37 {
  38         if (instr->addr + instr->len > mtd->size)
  39                 return -EINVAL;
  40
  41         memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  42
  43         instr->state = MTD_ERASE_DONE;
  44         mtd_erase_callback(instr);
  45
  46         return 0;
  47 }
  48
  49 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  50                 size_t *retlen, void **virt, resource_size_t *phys)
  51 {
  52         if (from + len > mtd->size)
  53                 return -EINVAL;
  54
  55         /* can we return a physical address with this driver? */
  56         if (phys)
  57                 return -EINVAL;
  58
  59         *virt = mtd->priv + from;
  60         *retlen = len;
  61         return 0;
  62 }
  63
  64 static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  65 {
  66 }
  67
  68 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  69                 size_t *retlen, u_char *buf)
  70 {
  71         if (from + len > mtd->size)
  72                 return -EINVAL;
  73
  74         memcpy(buf, mtd->priv + from, len);
  75
  76         *retlen = len;
  77         return 0;
  78 }
  79
  80 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  81                 size_t *retlen, const u_char *buf)
  82 {
  83         if (to + len > mtd->size)
  84                 return -EINVAL;
  85
  86         memcpy((char *)mtd->priv + to, buf, len);
  87
  88         *retlen = len;
  89         return 0;
  90 }
  91
  92 static void __exit cleanup_mtdram(void)
  93 {
  94         if (mtd_info) {
  95                 del_mtd_device(mtd_info);
  96                 vfree(mtd_info->priv);
  97                 kfree(mtd_info);
  98         }
  99 }
 100
 101 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 102                 unsigned long size, char *name)
 103 {
 104         memset(mtd, 0, sizeof(*mtd));
 105
 106         /* Setup the MTD structure */
 107         mtd->name = name;
 108         mtd->type = MTD_RAM;
 109         mtd->flags = MTD_CAP_RAM;
 110         mtd->size = size;
 111         mtd->writesize = 1;
 112         mtd->erasesize = MTDRAM_ERASE_SIZE;
 113         mtd->priv = mapped_address;
 114
 115         mtd->owner = THIS_MODULE;
 116         mtd->erase = ram_erase;
 117         mtd->point = ram_point;
 118         mtd->unpoint = ram_unpoint;
 119         mtd->read = ram_read;
 120         mtd->write = ram_write;
 121
 122         if (add_mtd_device(mtd)) {
 123                 return -EIO;
 124         }
 125
 126         return 0;
 127 }
 128
 129 static int __init init_mtdram(void)
 130 {
 131         void *addr;
 132         int err;
 133
 134         if (!total_size)
 135                 return -EINVAL;
 136
 137         /* Allocate some memory */
 138         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 139         if (!mtd_info)
 140                 return -ENOMEM;
 141
 142         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 143         if (!addr) {
 144                 kfree(mtd_info);
 145                 mtd_info = NULL;
 146                 return -ENOMEM;
 147         }
 148         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 149         if (err) {
 150                 vfree(addr);
 151                 kfree(mtd_info);
 152                 mtd_info = NULL;
 153                 return err;
 154         }
 155         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 156         return err;
 157 }
 158
 159 module_init(init_mtdram);
 160 module_exit(cleanup_mtdram);
 161
 162 MODULE_LICENSE("GPL");
 163 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 164 MODULE_DESCRIPTION("Simulated MTD driver for testing");