drivers/mtd/devices/phram.c

   1 /**
   2  *
   3  * $Id: phram.c,v 1.2 2004/08/09 13:19:44 dwmw2 Exp $
   4  *
   5  * Copyright (c) Jochen Schaeuble <psionic@psionic.de>
   6  * 07/2003      rewritten by Joern Engel <joern@wh.fh-wedel.de>
   7  *
   8  * DISCLAIMER:  This driver makes use of Rusty's excellent module code,
   9  * so it will not work for 2.4 without changes and it wont work for 2.4
  10  * as a module without major changes.  Oh well!
  11  *
  12  * Usage:
  13  *
  14  * one commend line parameter per device, each in the form:
  15  *   phram=<name>,<start>,<len>
  16  * <name> may be up to 63 characters.
  17  * <start> and <len> can be octal, decimal or hexadecimal.  If followed
  18  * by "k", "M" or "G", the numbers will be interpreted as kilo, mega or
  19  * gigabytes.
  20  *
  21  */
  22
  23 #include <asm/io.h>
  24 #include <linux/init.h>
  25 #include <linux/kernel.h>
  26 #include <linux/list.h>
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/mtd/mtd.h>
  30
  31 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args)
  32
  33 struct phram_mtd_list {
  34         struct list_head list;
  35         struct mtd_info *mtdinfo;
  36 };
  37
  38 static LIST_HEAD(phram_list);
  39
  40
  41
  42 int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
  43 {
  44         u_char *start = (u_char *)mtd->priv;
  45
  46         if (instr->addr + instr->len > mtd->size)
  47                 return -EINVAL;
  48
  49         memset(start + instr->addr, 0xff, instr->len);
  50
  51         /* This'll catch a few races. Free the thing before returning :)
  52          * I don't feel at all ashamed. This kind of thing is possible anyway
  53          * with flash, but unlikely.
  54          */
  55
  56         instr->state = MTD_ERASE_DONE;
  57
  58         mtd_erase_callback(instr);
  59
  60         return 0;
  61 }
  62
  63 int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  64                 size_t *retlen, u_char **mtdbuf)
  65 {
  66         u_char *start = (u_char *)mtd->priv;
  67
  68         if (from + len > mtd->size)
  69                 return -EINVAL;
  70
  71         *mtdbuf = start + from;
  72         *retlen = len;
  73         return 0;
  74 }
  75
  76 void phram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len)
  77 {
  78 }
  79
  80 int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  81                 size_t *retlen, u_char *buf)
  82 {
  83         u_char *start = (u_char *)mtd->priv;
  84
  85         if (from + len > mtd->size)
  86                 return -EINVAL;
  87
  88         memcpy(buf, start + from, len);
  89
  90         *retlen = len;
  91         return 0;
  92 }
  93
  94 int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
  95                 size_t *retlen, const u_char *buf)
  96 {
  97         u_char *start = (u_char *)mtd->priv;
  98
  99         if (to + len > mtd->size)
 100                 return -EINVAL;
 101
 102         memcpy(start + to, buf, len);
 103
 104         *retlen = len;
 105         return 0;
 106 }
 107
 108
 109
 110 static void unregister_devices(void)
 111 {
 112         struct phram_mtd_list *this;
 113
 114         list_for_each_entry(this, &phram_list, list) {
 115                 del_mtd_device(this->mtdinfo);
 116                 iounmap(this->mtdinfo->priv);
 117                 kfree(this->mtdinfo);
 118                 kfree(this);
 119         }
 120 }
 121
 122 static int register_device(char *name, unsigned long start, unsigned long len)
 123 {
 124         struct phram_mtd_list *new;
 125         int ret = -ENOMEM;
 126
 127         new = kmalloc(sizeof(*new), GFP_KERNEL);
 128         if (!new)
 129                 goto out0;
 130
 131         new->mtdinfo = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 132         if (!new->mtdinfo)
 133                 goto out1;
 134
 135         memset(new->mtdinfo, 0, sizeof(struct mtd_info));
 136
 137         ret = -EIO;
 138         new->mtdinfo->priv = ioremap(start, len);
 139         if (!new->mtdinfo->priv) {
 140                 ERROR("ioremap failed\n");
 141                 goto out2;
 142         }
 143
 144
 145         new->mtdinfo->name = name;
 146         new->mtdinfo->size = len;
 147         new->mtdinfo->flags = MTD_CAP_RAM | MTD_ERASEABLE | MTD_VOLATILE;
 148         new->mtdinfo->erase = phram_erase;
 149         new->mtdinfo->point = phram_point;
 150         new->mtdinfo->unpoint = phram_unpoint;
 151         new->mtdinfo->read = phram_read;
 152         new->mtdinfo->write = phram_write;
 153         new->mtdinfo->owner = THIS_MODULE;
 154         new->mtdinfo->type = MTD_RAM;
 155         new->mtdinfo->erasesize = 0x0;
 156
 157         ret = -EAGAIN;
 158         if (add_mtd_device(new->mtdinfo)) {
 159                 ERROR("Failed to register new device\n");
 160                 goto out3;
 161         }
 162
 163         list_add_tail(&new->list, &phram_list);
 164         return 0;
 165
 166 out3:
 167         iounmap(new->mtdinfo->priv);
 168 out2:
 169         kfree(new->mtdinfo);
 170 out1:
 171         kfree(new);
 172 out0:
 173         return ret;
 174 }
 175
 176 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 177 {
 178         unsigned long result = simple_strtoul(cp, endp, base);
 179
 180         switch (**endp) {
 181         case 'G':
 182                 result *= 1024;
 183         case 'M':
 184                 result *= 1024;
 185         case 'k':
 186                 result *= 1024;
 187                 endp++;
 188         }
 189         return result;
 190 }
 191
 192 static int parse_num32(uint32_t *num32, const char *token)
 193 {
 194         char *endp;
 195         unsigned long n;
 196
 197         n = ustrtoul(token, &endp, 0);
 198         if (*endp)
 199                 return -EINVAL;
 200
 201         *num32 = n;
 202         return 0;
 203 }
 204
 205 static int parse_name(char **pname, const char *token)
 206 {
 207         size_t len;
 208         char *name;
 209
 210         len = strlen(token) + 1;
 211         if (len > 64)
 212                 return -ENOSPC;
 213
 214         name = kmalloc(len, GFP_KERNEL);
 215         if (!name)
 216                 return -ENOMEM;
 217
 218         strcpy(name, token);
 219
 220         *pname = name;
 221         return 0;
 222 }
 223
 224 #define parse_err(fmt, args...) do {    \
 225         ERROR(fmt , ## args);   \
 226         return 0;               \
 227 } while (0)
 228
 229 static int phram_setup(const char *val, struct kernel_param *kp)
 230 {
 231         char buf[64+12+12], *str = buf;
 232         char *token[3];
 233         char *name;
 234         uint32_t start;
 235         uint32_t len;
 236         int i, ret;
 237
 238         if (strnlen(val, sizeof(str)) >= sizeof(str))
 239                 parse_err("parameter too long\n");
 240
 241         strcpy(str, val);
 242
 243         for (i=0; i<3; i++)
 244                 token[i] = strsep(&str, ",");
 245
 246         if (str)
 247                 parse_err("too many arguments\n");
 248
 249         if (!token[2])
 250                 parse_err("not enough arguments\n");
 251
 252         ret = parse_name(&name, token[0]);
 253         if (ret == -ENOMEM)
 254                 parse_err("out of memory\n");
 255         if (ret == -ENOSPC)
 256                 parse_err("name too long\n");
 257         if (ret)
 258                 return 0;
 259
 260         ret = parse_num32(&start, token[1]);
 261         if (ret)
 262                 parse_err("illegal start address\n");
 263
 264         ret = parse_num32(&len, token[2]);
 265         if (ret)
 266                 parse_err("illegal device length\n");
 267
 268         register_device(name, start, len);
 269
 270         return 0;
 271 }
 272
 273 module_param_call(phram, phram_setup, NULL, NULL, 000);
 274 MODULE_PARM_DESC(phram, "Memory region to map. \"map=<name>,<start><length>\"");
 275
 276 /*
 277  * Just for compatibility with slram, this is horrible and should go someday.
 278  */
 279 static int __init slram_setup(const char *val, struct kernel_param *kp)
 280 {
 281         char buf[256], *str = buf;
 282
 283         if (!val || !val[0])
 284                 parse_err("no arguments to \"slram=\"\n");
 285
 286         if (strnlen(val, sizeof(str)) >= sizeof(str))
 287                 parse_err("parameter too long\n");
 288
 289         strcpy(str, val);
 290
 291         while (str) {
 292                 char *token[3];
 293                 char *name;
 294                 uint32_t start;
 295                 uint32_t len;
 296                 int i, ret;
 297
 298                 for (i=0; i<3; i++) {
 299                         token[i] = strsep(&str, ",");
 300                         if (token[i])
 301                                 continue;
 302                         parse_err("wrong number of arguments to \"slram=\"\n");
 303                 }
 304
 305                 /* name */
 306                 ret = parse_name(&name, token[0]);
 307                 if (ret == -ENOMEM)
 308                         parse_err("of memory\n");
 309                 if (ret == -ENOSPC)
 310                         parse_err("too long\n");
 311                 if (ret)
 312                         return 1;
 313
 314                 /* start */
 315                 ret = parse_num32(&start, token[1]);
 316                 if (ret)
 317                         parse_err("illegal start address\n");
 318
 319                 /* len */
 320                 if (token[2][0] == '+')
 321                         ret = parse_num32(&len, token[2] + 1);
 322                 else
 323                         ret = parse_num32(&len, token[2]);
 324
 325                 if (ret)
 326                         parse_err("illegal device length\n");
 327
 328                 if (token[2][0] != '+') {
 329                         if (len < start)
 330                                 parse_err("end < start\n");
 331                         len -= start;
 332                 }
 333
 334                 register_device(name, start, len);
 335         }
 336         return 1;
 337 }
 338
 339 module_param_call(slram, slram_setup, NULL, NULL, 000);
 340 MODULE_PARM_DESC(slram, "List of memory regions to map. \"map=<name>,<start><length/end>\"");
 341
 342
 343 int __init init_phram(void)
 344 {
 345         printk(KERN_ERR "phram loaded\n");
 346         return 0;
 347 }
 348
 349 static void __exit cleanup_phram(void)
 350 {
 351         unregister_devices();
 352 }
 353
 354 module_init(init_phram);
 355 module_exit(cleanup_phram);
 356
 357 MODULE_LICENSE("GPL");
 358 MODULE_AUTHOR("Jörn Engel <joern@wh.fh-wedel.de>");
 359 MODULE_DESCRIPTION("MTD driver for physical RAM");