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) "phram: " 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                 del_mtd_device(&this->mtd);
 119                 iounmap(this->mtd.priv);
 120                 kfree(this);
 121         }
 122 }
 123
 124 static int register_device(char *name, unsigned long start, unsigned long len)
 125 {
 126         struct phram_mtd_list *new;
 127         int ret = -ENOMEM;
 128
 129         new = kzalloc(sizeof(*new), GFP_KERNEL);
 130         if (!new)
 131                 goto out0;
 132
 133         ret = -EIO;
 134         new->mtd.priv = ioremap(start, len);
 135         if (!new->mtd.priv) {
 136                 pr_err("ioremap failed\n");
 137                 goto out1;
 138         }
 139
 140
 141         new->mtd.name = name;
 142         new->mtd.size = len;
 143         new->mtd.flags = MTD_CAP_RAM;
 144         new->mtd.erase = phram_erase;
 145         new->mtd.point = phram_point;
 146         new->mtd.unpoint = phram_unpoint;
 147         new->mtd.read = phram_read;
 148         new->mtd.write = phram_write;
 149         new->mtd.owner = THIS_MODULE;
 150         new->mtd.type = MTD_RAM;
 151         new->mtd.erasesize = PAGE_SIZE;
 152         new->mtd.writesize = 1;
 153
 154         ret = -EAGAIN;
 155         if (add_mtd_device(&new->mtd)) {
 156                 pr_err("Failed to register new device\n");
 157                 goto out2;
 158         }
 159
 160         list_add_tail(&new->list, &phram_list);
 161         return 0;
 162
 163 out2:
 164         iounmap(new->mtd.priv);
 165 out1:
 166         kfree(new);
 167 out0:
 168         return ret;
 169 }
 170
 171 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 172 {
 173         unsigned long result = simple_strtoul(cp, endp, base);
 174
 175         switch (**endp) {
 176         case 'G':
 177                 result *= 1024;
 178         case 'M':
 179                 result *= 1024;
 180         case 'k':
 181                 result *= 1024;
 182         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 183                 if ((*endp)[1] == 'i')
 184                         (*endp) += 2;
 185         }
 186         return result;
 187 }
 188
 189 static int parse_num32(uint32_t *num32, const char *token)
 190 {
 191         char *endp;
 192         unsigned long n;
 193
 194         n = ustrtoul(token, &endp, 0);
 195         if (*endp)
 196                 return -EINVAL;
 197
 198         *num32 = n;
 199         return 0;
 200 }
 201
 202 static int parse_name(char **pname, const char *token)
 203 {
 204         size_t len;
 205         char *name;
 206
 207         len = strlen(token) + 1;
 208         if (len > 64)
 209                 return -ENOSPC;
 210
 211         name = kmalloc(len, GFP_KERNEL);
 212         if (!name)
 213                 return -ENOMEM;
 214
 215         strcpy(name, token);
 216
 217         *pname = name;
 218         return 0;
 219 }
 220
 221
 222 static inline void kill_final_newline(char *str)
 223 {
 224         char *newline = strrchr(str, '\n');
 225         if (newline && !newline[1])
 226                 *newline = 0;
 227 }
 228
 229
 230 #define parse_err(fmt, args...) do {    \
 231         pr_err(fmt , ## args);  \
 232         return 1;               \
 233 } while (0)
 234
 235 static int phram_setup(const char *val, struct kernel_param *kp)
 236 {
 237         char buf[64+12+12], *str = buf;
 238         char *token[3];
 239         char *name;
 240         uint32_t start;
 241         uint32_t len;
 242         int i, ret;
 243
 244         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 245                 parse_err("parameter too long\n");
 246
 247         strcpy(str, val);
 248         kill_final_newline(str);
 249
 250         for (i=0; i<3; i++)
 251                 token[i] = strsep(&str, ",");
 252
 253         if (str)
 254                 parse_err("too many arguments\n");
 255
 256         if (!token[2])
 257                 parse_err("not enough arguments\n");
 258
 259         ret = parse_name(&name, token[0]);
 260         if (ret)
 261                 return ret;
 262
 263         ret = parse_num32(&start, token[1]);
 264         if (ret) {
 265                 kfree(name);
 266                 parse_err("illegal start address\n");
 267         }
 268
 269         ret = parse_num32(&len, token[2]);
 270         if (ret) {
 271                 kfree(name);
 272                 parse_err("illegal device length\n");
 273         }
 274
 275         ret = register_device(name, start, len);
 276         if (!ret)
 277                 pr_info("%s device: %#x at %#x\n", name, len, start);
 278
 279         return ret;
 280 }
 281
 282 module_param_call(phram, phram_setup, NULL, NULL, 000);
 283 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 284
 285
 286 static int __init init_phram(void)
 287 {
 288         return 0;
 289 }
 290
 291 static void __exit cleanup_phram(void)
 292 {
 293         unregister_devices();
 294 }
 295
 296 module_init(init_phram);
 297 module_exit(cleanup_phram);
 298
 299 MODULE_LICENSE("GPL");
 300 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
 301 MODULE_DESCRIPTION("MTD driver for physical RAM");