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 check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
  36 {
  37         int ret = 0;
  38
  39         /* Start address must align on block boundary */
  40         if (mtd_mod_by_eb(ofs, mtd)) {
  41                 pr_debug("%s: unaligned address\n", __func__);
  42                 ret = -EINVAL;
  43         }
  44
  45         /* Length must align on block boundary */
  46         if (mtd_mod_by_eb(len, mtd)) {
  47                 pr_debug("%s: length not block aligned\n", __func__);
  48                 ret = -EINVAL;
  49         }
  50
  51         return ret;
  52 }
  53
  54 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
  55 {
  56         if (check_offs_len(mtd, instr->addr, instr->len))
  57                 return -EINVAL;
  58         memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  59         instr->state = MTD_ERASE_DONE;
  60         mtd_erase_callback(instr);
  61         return 0;
  62 }
  63
  64 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
  65                 size_t *retlen, void **virt, resource_size_t *phys)
  66 {
  67         *virt = mtd->priv + from;
  68         *retlen = len;
  69         return 0;
  70 }
  71
  72 static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  73 {
  74         return 0;
  75 }
  76
  77 /*
  78  * Allow NOMMU mmap() to directly map the device (if not NULL)
  79  * - return the address to which the offset maps
  80  * - return -ENOSYS to indicate refusal to do the mapping
  81  */
  82 static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
  83                                            unsigned long len,
  84                                            unsigned long offset,
  85                                            unsigned long flags)
  86 {
  87         return (unsigned long) mtd->priv + offset;
  88 }
  89
  90 static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
  91                 size_t *retlen, u_char *buf)
  92 {
  93         memcpy(buf, mtd->priv + from, len);
  94         *retlen = len;
  95         return 0;
  96 }
  97
  98 static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
  99                 size_t *retlen, const u_char *buf)
 100 {
 101         memcpy((char *)mtd->priv + to, buf, len);
 102         *retlen = len;
 103         return 0;
 104 }
 105
 106 static void __exit cleanup_mtdram(void)
 107 {
 108         if (mtd_info) {
 109                 mtd_device_unregister(mtd_info);
 110                 vfree(mtd_info->priv);
 111                 kfree(mtd_info);
 112         }
 113 }
 114
 115 int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
 116                 unsigned long size, const char *name)
 117 {
 118         memset(mtd, 0, sizeof(*mtd));
 119
 120         /* Setup the MTD structure */
 121         mtd->name = name;
 122         mtd->type = MTD_RAM;
 123         mtd->flags = MTD_CAP_RAM;
 124         mtd->size = size;
 125         mtd->writesize = 1;
 126         mtd->writebufsize = 64; /* Mimic CFI NOR flashes */
 127         mtd->erasesize = MTDRAM_ERASE_SIZE;
 128         mtd->priv = mapped_address;
 129
 130         mtd->owner = THIS_MODULE;
 131         mtd->_erase = ram_erase;
 132         mtd->_point = ram_point;
 133         mtd->_unpoint = ram_unpoint;
 134         mtd->_get_unmapped_area = ram_get_unmapped_area;
 135         mtd->_read = ram_read;
 136         mtd->_write = ram_write;
 137
 138         if (mtd_device_register(mtd, NULL, 0))
 139                 return -EIO;
 140
 141         return 0;
 142 }
 143
 144 static int __init init_mtdram(void)
 145 {
 146         void *addr;
 147         int err;
 148
 149         if (!total_size)
 150                 return -EINVAL;
 151
 152         /* Allocate some memory */
 153         mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 154         if (!mtd_info)
 155                 return -ENOMEM;
 156
 157         addr = vmalloc(MTDRAM_TOTAL_SIZE);
 158         if (!addr) {
 159                 kfree(mtd_info);
 160                 mtd_info = NULL;
 161                 return -ENOMEM;
 162         }
 163         err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
 164         if (err) {
 165                 vfree(addr);
 166                 kfree(mtd_info);
 167                 mtd_info = NULL;
 168                 return err;
 169         }
 170         memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
 171         return err;
 172 }
 173
 174 module_init(init_mtdram);
 175 module_exit(cleanup_mtdram);
 176
 177 MODULE_LICENSE("GPL");
 178 MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
 179 MODULE_DESCRIPTION("Simulated MTD driver for testing");