drivers/mtd/devices/phram.c

   1 /**
   2  * $Id: phram.c,v 1.11 2005/01/05 18:05:13 dwmw2 Exp $
   3  *
   4  * Copyright (c) ????           Jochen Schäuble <psionic@psionic.de>
   5  * Copyright (c) 2003-2004      Jörn Engel <joern@wh.fh-wedel.de>
   6  *
   7  * Usage:
   8  *
   9  * one commend line parameter per device, each in the form:
  10  *   phram=<name>,<start>,<len>
  11  * <name> may be up to 63 characters.
  12  * <start> and <len> can be octal, decimal or hexadecimal.  If followed
  13  * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
  14  * gigabytes.
  15  *
  16  * Example:
  17  *      phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
  18  *
  19  */
  20
  21 #include <asm/io.h>
  22 #include <linux/init.h>
  23 #include <linux/kernel.h>
  24 #include <linux/list.h>
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/mtd/mtd.h>
  28
  29 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args)
  30
  31 struct phram_mtd_list {
  32         struct mtd_info mtd;
  33         struct list_head list;
  34 };
  35
  36 static LIST_HEAD(phram_list);
  37
  38
  39
  40 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
  41 {
  42         u_char *start = mtd->priv;
  43
  44         if (instr->addr + instr->len > mtd->size)
  45                 return -EINVAL;
  46
  47         memset(start + instr->addr, 0xff, instr->len);
  48
  49         /* This'll catch a few races. Free the thing before returning :)
  50          * I don't feel at all ashamed. This kind of thing is possible anyway
  51          * with flash, but unlikely.
  52          */
  53
  54         instr->state = MTD_ERASE_DONE;
  55
  56         mtd_erase_callback(instr);
  57
  58         return 0;
  59 }
  60
  61 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  62                 size_t *retlen, u_char **mtdbuf)
  63 {
  64         u_char *start = mtd->priv;
  65
  66         if (from + len > mtd->size)
  67                 return -EINVAL;
  68
  69         *mtdbuf = start + from;
  70         *retlen = len;
  71         return 0;
  72 }
  73
  74 static void phram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len)
  75 {
  76 }
  77
  78 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  79                 size_t *retlen, u_char *buf)
  80 {
  81         u_char *start = mtd->priv;
  82
  83         if (from + len > mtd->size)
  84                 return -EINVAL;
  85
  86         memcpy(buf, start + from, len);
  87
  88         *retlen = len;
  89         return 0;
  90 }
  91
  92 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
  93                 size_t *retlen, const u_char *buf)
  94 {
  95         u_char *start = mtd->priv;
  96
  97         if (to + len > mtd->size)
  98                 return -EINVAL;
  99
 100         memcpy(start + to, buf, len);
 101
 102         *retlen = len;
 103         return 0;
 104 }
 105
 106
 107
 108 static void unregister_devices(void)
 109 {
 110         struct phram_mtd_list *this;
 111
 112         list_for_each_entry(this, &phram_list, list) {
 113                 del_mtd_device(&this->mtd);
 114                 iounmap(this->mtd.priv);
 115                 kfree(this);
 116         }
 117 }
 118
 119 static int register_device(char *name, unsigned long start, unsigned long len)
 120 {
 121         struct phram_mtd_list *new;
 122         int ret = -ENOMEM;
 123
 124         new = kmalloc(sizeof(*new), GFP_KERNEL);
 125         if (!new)
 126                 goto out0;
 127
 128         memset(new, 0, sizeof(*new));
 129
 130         ret = -EIO;
 131         new->mtd.priv = ioremap(start, len);
 132         if (!new->mtd.priv) {
 133                 ERROR("ioremap failed\n");
 134                 goto out1;
 135         }
 136
 137
 138         new->mtd.name = name;
 139         new->mtd.size = len;
 140         new->mtd.flags = MTD_CAP_RAM | MTD_ERASEABLE | MTD_VOLATILE;
 141         new->mtd.erase = phram_erase;
 142         new->mtd.point = phram_point;
 143         new->mtd.unpoint = phram_unpoint;
 144         new->mtd.read = phram_read;
 145         new->mtd.write = phram_write;
 146         new->mtd.owner = THIS_MODULE;
 147         new->mtd.type = MTD_RAM;
 148         new->mtd.erasesize = 0;
 149
 150         ret = -EAGAIN;
 151         if (add_mtd_device(&new->mtd)) {
 152                 ERROR("Failed to register new device\n");
 153                 goto out2;
 154         }
 155
 156         list_add_tail(&new->list, &phram_list);
 157         return 0;
 158
 159 out2:
 160         iounmap(new->mtd.priv);
 161 out1:
 162         kfree(new);
 163 out0:
 164         return ret;
 165 }
 166
 167 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 168 {
 169         unsigned long result = simple_strtoul(cp, endp, base);
 170
 171         switch (**endp) {
 172         case 'G':
 173                 result *= 1024;
 174         case 'M':
 175                 result *= 1024;
 176         case 'k':
 177                 result *= 1024;
 178         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 179                 if ((*endp)[1] == 'i')
 180                         (*endp) += 2;
 181         }
 182         return result;
 183 }
 184
 185 static int parse_num32(uint32_t *num32, const char *token)
 186 {
 187         char *endp;
 188         unsigned long n;
 189
 190         n = ustrtoul(token, &endp, 0);
 191         if (*endp)
 192                 return -EINVAL;
 193
 194         *num32 = n;
 195         return 0;
 196 }
 197
 198 static int parse_name(char **pname, const char *token)
 199 {
 200         size_t len;
 201         char *name;
 202
 203         len = strlen(token) + 1;
 204         if (len > 64)
 205                 return -ENOSPC;
 206
 207         name = kmalloc(len, GFP_KERNEL);
 208         if (!name)
 209                 return -ENOMEM;
 210
 211         strcpy(name, token);
 212
 213         *pname = name;
 214         return 0;
 215 }
 216
 217 #define parse_err(fmt, args...) do {    \
 218         ERROR(fmt , ## args);   \
 219         return 0;               \
 220 } while (0)
 221
 222 static int phram_setup(const char *val, struct kernel_param *kp)
 223 {
 224         char buf[64+12+12], *str = buf;
 225         char *token[3];
 226         char *name;
 227         uint32_t start;
 228         uint32_t len;
 229         int i, ret;
 230
 231         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 232                 parse_err("parameter too long\n");
 233
 234         strcpy(str, val);
 235
 236         for (i=0; i<3; i++)
 237                 token[i] = strsep(&str, ",");
 238
 239         if (str)
 240                 parse_err("too many arguments\n");
 241
 242         if (!token[2])
 243                 parse_err("not enough arguments\n");
 244
 245         ret = parse_name(&name, token[0]);
 246         if (ret == -ENOMEM)
 247                 parse_err("out of memory\n");
 248         if (ret == -ENOSPC)
 249                 parse_err("name too long\n");
 250         if (ret)
 251                 return 0;
 252
 253         ret = parse_num32(&start, token[1]);
 254         if (ret)
 255                 parse_err("illegal start address\n");
 256
 257         ret = parse_num32(&len, token[2]);
 258         if (ret)
 259                 parse_err("illegal device length\n");
 260
 261         register_device(name, start, len);
 262
 263         return 0;
 264 }
 265
 266 module_param_call(phram, phram_setup, NULL, NULL, 000);
 267 MODULE_PARM_DESC(phram,"Memory region to map. \"map=<name>,<start>,<length>\"");
 268
 269
 270 static int __init init_phram(void)
 271 {
 272         return 0;
 273 }
 274
 275 static void __exit cleanup_phram(void)
 276 {
 277         unregister_devices();
 278 }
 279
 280 module_init(init_phram);
 281 module_exit(cleanup_phram);
 282
 283 MODULE_LICENSE("GPL");
 284 MODULE_AUTHOR("Jörn Engel <joern@wh.fh-wedel.de>");
 285 MODULE_DESCRIPTION("MTD driver for physical RAM");