drivers/mtd/devices/phram.c

   1 /**
   2  * Copyright (c) ????           Jochen Schäuble <psionic@psionic.de>
   3  * Copyright (c) 2003-2004      Joern Engel <joern@wh.fh-wedel.de>
   4  *
   5  * Usage:
   6  *
   7  * one commend line parameter per device, each in the form:
   8  *   phram=<name>,<start>,<len>
   9  * <name> may be up to 63 characters.
  10  * <start> and <len> can be octal, decimal or hexadecimal.  If followed
  11  * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
  12  * gigabytes.
  13  *
  14  * Example:
  15  *      phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <asm/io.h>
  21 #include <linux/init.h>
  22 #include <linux/kernel.h>
  23 #include <linux/list.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/slab.h>
  27 #include <linux/mtd/mtd.h>
  28
  29 struct phram_mtd_list {
  30         struct mtd_info mtd;
  31         struct list_head list;
  32 };
  33
  34 static LIST_HEAD(phram_list);
  35
  36
  37 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
  38 {
  39         u_char *start = mtd->priv;
  40
  41         if (instr->addr + instr->len > mtd->size)
  42                 return -EINVAL;
  43
  44         memset(start + instr->addr, 0xff, instr->len);
  45
  46         /* This'll catch a few races. Free the thing before returning :)
  47          * I don't feel at all ashamed. This kind of thing is possible anyway
  48          * with flash, but unlikely.
  49          */
  50
  51         instr->state = MTD_ERASE_DONE;
  52
  53         mtd_erase_callback(instr);
  54
  55         return 0;
  56 }
  57
  58 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  59                 size_t *retlen, void **virt, resource_size_t *phys)
  60 {
  61         if (from + len > mtd->size)
  62                 return -EINVAL;
  63
  64         /* can we return a physical address with this driver? */
  65         if (phys)
  66                 return -EINVAL;
  67
  68         *virt = mtd->priv + from;
  69         *retlen = len;
  70         return 0;
  71 }
  72
  73 static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  74 {
  75 }
  76
  77 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  78                 size_t *retlen, u_char *buf)
  79 {
  80         u_char *start = mtd->priv;
  81
  82         if (from >= mtd->size)
  83                 return -EINVAL;
  84
  85         if (len > mtd->size - from)
  86                 len = mtd->size - from;
  87
  88         memcpy(buf, start + from, len);
  89
  90         *retlen = len;
  91         return 0;
  92 }
  93
  94 static 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 = mtd->priv;
  98
  99         if (to >= mtd->size)
 100                 return -EINVAL;
 101
 102         if (len > mtd->size - to)
 103                 len = mtd->size - to;
 104
 105         memcpy(start + to, buf, len);
 106
 107         *retlen = len;
 108         return 0;
 109 }
 110
 111
 112
 113 static void unregister_devices(void)
 114 {
 115         struct phram_mtd_list *this, *safe;
 116
 117         list_for_each_entry_safe(this, safe, &phram_list, list) {
 118                 mtd_device_unregister(&this->mtd);
 119                 iounmap(this->mtd.priv);
 120                 kfree(this->mtd.name);
 121                 kfree(this);
 122         }
 123 }
 124
 125 static int register_device(char *name, unsigned long start, unsigned long len)
 126 {
 127         struct phram_mtd_list *new;
 128         int ret = -ENOMEM;
 129
 130         new = kzalloc(sizeof(*new), GFP_KERNEL);
 131         if (!new)
 132                 goto out0;
 133
 134         ret = -EIO;
 135         new->mtd.priv = ioremap(start, len);
 136         if (!new->mtd.priv) {
 137                 pr_err("ioremap failed\n");
 138                 goto out1;
 139         }
 140
 141
 142         new->mtd.name = name;
 143         new->mtd.size = len;
 144         new->mtd.flags = MTD_CAP_RAM;
 145         new->mtd.erase = phram_erase;
 146         new->mtd.point = phram_point;
 147         new->mtd.unpoint = phram_unpoint;
 148         new->mtd.read = phram_read;
 149         new->mtd.write = phram_write;
 150         new->mtd.owner = THIS_MODULE;
 151         new->mtd.type = MTD_RAM;
 152         new->mtd.erasesize = PAGE_SIZE;
 153         new->mtd.writesize = 1;
 154
 155         ret = -EAGAIN;
 156         if (mtd_device_register(&new->mtd, NULL, 0)) {
 157                 pr_err("Failed to register new device\n");
 158                 goto out2;
 159         }
 160
 161         list_add_tail(&new->list, &phram_list);
 162         return 0;
 163
 164 out2:
 165         iounmap(new->mtd.priv);
 166 out1:
 167         kfree(new);
 168 out0:
 169         return ret;
 170 }
 171
 172 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 173 {
 174         unsigned long result = simple_strtoul(cp, endp, base);
 175
 176         switch (**endp) {
 177         case 'G':
 178                 result *= 1024;
 179         case 'M':
 180                 result *= 1024;
 181         case 'k':
 182                 result *= 1024;
 183         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 184                 if ((*endp)[1] == 'i')
 185                         (*endp) += 2;
 186         }
 187         return result;
 188 }
 189
 190 static int parse_num32(uint32_t *num32, const char *token)
 191 {
 192         char *endp;
 193         unsigned long n;
 194
 195         n = ustrtoul(token, &endp, 0);
 196         if (*endp)
 197                 return -EINVAL;
 198
 199         *num32 = n;
 200         return 0;
 201 }
 202
 203 static int parse_name(char **pname, const char *token)
 204 {
 205         size_t len;
 206         char *name;
 207
 208         len = strlen(token) + 1;
 209         if (len > 64)
 210                 return -ENOSPC;
 211
 212         name = kmalloc(len, GFP_KERNEL);
 213         if (!name)
 214                 return -ENOMEM;
 215
 216         strcpy(name, token);
 217
 218         *pname = name;
 219         return 0;
 220 }
 221
 222
 223 static inline void kill_final_newline(char *str)
 224 {
 225         char *newline = strrchr(str, '\n');
 226         if (newline && !newline[1])
 227                 *newline = 0;
 228 }
 229
 230
 231 #define parse_err(fmt, args...) do {    \
 232         pr_err(fmt , ## args);  \
 233         return 1;               \
 234 } while (0)
 235
 236 static int phram_setup(const char *val, struct kernel_param *kp)
 237 {
 238         char buf[64+12+12], *str = buf;
 239         char *token[3];
 240         char *name;
 241         uint32_t start;
 242         uint32_t len;
 243         int i, ret;
 244
 245         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 246                 parse_err("parameter too long\n");
 247
 248         strcpy(str, val);
 249         kill_final_newline(str);
 250
 251         for (i=0; i<3; i++)
 252                 token[i] = strsep(&str, ",");
 253
 254         if (str)
 255                 parse_err("too many arguments\n");
 256
 257         if (!token[2])
 258                 parse_err("not enough arguments\n");
 259
 260         ret = parse_name(&name, token[0]);
 261         if (ret)
 262                 return ret;
 263
 264         ret = parse_num32(&start, token[1]);
 265         if (ret) {
 266                 kfree(name);
 267                 parse_err("illegal start address\n");
 268         }
 269
 270         ret = parse_num32(&len, token[2]);
 271         if (ret) {
 272                 kfree(name);
 273                 parse_err("illegal device length\n");
 274         }
 275
 276         ret = register_device(name, start, len);
 277         if (!ret)
 278                 pr_info("%s device: %#x at %#x\n", name, len, start);
 279         else
 280                 kfree(name);
 281
 282         return ret;
 283 }
 284
 285 module_param_call(phram, phram_setup, NULL, NULL, 000);
 286 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 287
 288
 289 static int __init init_phram(void)
 290 {
 291         return 0;
 292 }
 293
 294 static void __exit cleanup_phram(void)
 295 {
 296         unregister_devices();
 297 }
 298
 299 module_init(init_phram);
 300 module_exit(cleanup_phram);
 301
 302 MODULE_LICENSE("GPL");
 303 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
 304 MODULE_DESCRIPTION("MTD driver for physical RAM");