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 void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  64 {
  65 }
  66
  67 /*
  68  * Allow NOMMU mmap() to directly map the device (if not NULL)
  69  * - return the address to which the offset maps
  70  * - return -ENOSYS to indicate refusal to do the mapping
  71  */
  72 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  73                                            unsigned long len,
  74                                            unsigned long offset,
  75                                            unsigned long flags)
  76 {
  77         return (unsigned long) mtd->priv + offset;
  78 }
  79
  80 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  81                 size_t *retlen, u_char *buf)
  82 {
  83         if (from + len > mtd->size)
  84                 return -EINVAL;
  85
  86         memcpy(buf, mtd->priv + from, len);
  87
  88         *retlen = len;
  89         return 0;
  90 }
  91
  92 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  93                 size_t *retlen, const u_char *buf)
  94 {
  95         if (to + len > mtd->size)
  96                 return -EINVAL;
  97
  98         memcpy((char *)mtd->priv + to, buf, len);
  99
 100         *retlen = len;
 101         return 0;
 102 }
 103
 104 static void __exit cleanup_mtdram(void)
 105 {
 106         if (mtd_info) {
 107                 mtd_device_unregister(mtd_info);
 108                 vfree(mtd_info->priv);
 109                 kfree(mtd_info);
 110         }
 111 }
 112
 113 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 114                 unsigned long size, char *name)
 115 {
 116         memset(mtd, 0, sizeof(*mtd));
 117
 118         /* Setup the MTD structure */
 119         mtd->name = name;
 120         mtd->type = MTD_RAM;
 121         mtd->flags = MTD_CAP_RAM;
 122         mtd->size = size;
 123         mtd->writesize = 1;
 124         mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
 125         mtd->erasesize = MTDRAM_ERASE_SIZE;
 126         mtd->priv = mapped_address;
 127
 128         mtd->owner = THIS_MODULE;
 129         mtd->erase = ram_erase;
 130         mtd->point = ram_point;
 131         mtd->unpoint = ram_unpoint;
 132         mtd->get_unmapped_area = ram_get_unmapped_area;
 133         mtd->read = ram_read;
 134         mtd->write = ram_write;
 135
 136         if (mtd_device_register(mtd, NULL, 0))
 137                 return -EIO;
 138
 139         return 0;
 140 }
 141
 142 static int __init init_mtdram(void)
 143 {
 144         void *addr;
 145         int err;
 146
 147         if (!total_size)
 148                 return -EINVAL;
 149
 150         /* Allocate some memory */
 151         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 152         if (!mtd_info)
 153                 return -ENOMEM;
 154
 155         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 156         if (!addr) {
 157                 kfree(mtd_info);
 158                 mtd_info = NULL;
 159                 return -ENOMEM;
 160         }
 161         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 162         if (err) {
 163                 vfree(addr);
 164                 kfree(mtd_info);
 165                 mtd_info = NULL;
 166                 return err;
 167         }
 168         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 169         return err;
 170 }
 171
 172 module_init(init_mtdram);
 173 module_exit(cleanup_mtdram);
 174
 175 MODULE_LICENSE("GPL");
 176 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 177 MODULE_DESCRIPTION("Simulated MTD driver for testing");