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 <linux/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 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
  37 {
  38         u_char *start = mtd->priv;
  39
  40         memset(start + instr->addr, 0xff, instr->len);
  41
  42         return 0;
  43 }
  44
  45 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  46                 size_t *retlen, void **virt, resource_size_t *phys)
  47 {
  48         *virt = mtd->priv + from;
  49         *retlen = len;
  50         return 0;
  51 }
  52
  53 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  54 {
  55         return 0;
  56 }
  57
  58 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  59                 size_t *retlen, u_char *buf)
  60 {
  61         u_char *start = mtd->priv;
  62
  63         memcpy(buf, start + from, len);
  64         *retlen = len;
  65         return 0;
  66 }
  67
  68 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
  69                 size_t *retlen, const u_char *buf)
  70 {
  71         u_char *start = mtd->priv;
  72
  73         memcpy(start + to, buf, len);
  74         *retlen = len;
  75         return 0;
  76 }
  77
  78 static void unregister_devices(void)
  79 {
  80         struct phram_mtd_list *this, *safe;
  81
  82         list_for_each_entry_safe(this, safe, &phram_list, list) {
  83                 mtd_device_unregister(&this->mtd);
  84                 iounmap(this->mtd.priv);
  85                 kfree(this->mtd.name);
  86                 kfree(this);
  87         }
  88 }
  89
  90 static int register_device(char *name, phys_addr_t start, size_t len)
  91 {
  92         struct phram_mtd_list *new;
  93         int ret = -ENOMEM;
  94
  95         new = kzalloc(sizeof(*new), GFP_KERNEL);
  96         if (!new)
  97                 goto out0;
  98
  99         ret = -EIO;
 100         new->mtd.priv = ioremap(start, len);
 101         if (!new->mtd.priv) {
 102                 pr_err("ioremap failed\n");
 103                 goto out1;
 104         }
 105
 106
 107         new->mtd.name = name;
 108         new->mtd.size = len;
 109         new->mtd.flags = MTD_CAP_RAM;
 110         new->mtd._erase = phram_erase;
 111         new->mtd._point = phram_point;
 112         new->mtd._unpoint = phram_unpoint;
 113         new->mtd._read = phram_read;
 114         new->mtd._write = phram_write;
 115         new->mtd.owner = THIS_MODULE;
 116         new->mtd.type = MTD_RAM;
 117         new->mtd.erasesize = PAGE_SIZE;
 118         new->mtd.writesize = 1;
 119
 120         ret = -EAGAIN;
 121         if (mtd_device_register(&new->mtd, NULL, 0)) {
 122                 pr_err("Failed to register new device\n");
 123                 goto out2;
 124         }
 125
 126         list_add_tail(&new->list, &phram_list);
 127         return 0;
 128
 129 out2:
 130         iounmap(new->mtd.priv);
 131 out1:
 132         kfree(new);
 133 out0:
 134         return ret;
 135 }
 136
 137 static int parse_num64(uint64_t *num64, char *token)
 138 {
 139         size_t len;
 140         int shift = 0;
 141         int ret;
 142
 143         len = strlen(token);
 144         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 145         if (len > 2) {
 146                 if (token[len - 1] == 'i') {
 147                         switch (token[len - 2]) {
 148                         case 'G':
 149                                 shift += 10;
 150                                 /* fall through */
 151                         case 'M':
 152                                 shift += 10;
 153                                 /* fall through */
 154                         case 'k':
 155                                 shift += 10;
 156                                 token[len - 2] = 0;
 157                                 break;
 158                         default:
 159                                 return -EINVAL;
 160                         }
 161                 }
 162         }
 163
 164         ret = kstrtou64(token, 0, num64);
 165         *num64 <<= shift;
 166
 167         return ret;
 168 }
 169
 170 static int parse_name(char **pname, const char *token)
 171 {
 172         size_t len;
 173         char *name;
 174
 175         len = strlen(token) + 1;
 176         if (len > 64)
 177                 return -ENOSPC;
 178
 179         name = kstrdup(token, GFP_KERNEL);
 180         if (!name)
 181                 return -ENOMEM;
 182
 183         *pname = name;
 184         return 0;
 185 }
 186
 187
 188 static inline void kill_final_newline(char *str)
 189 {
 190         char *newline = strrchr(str, '\n');
 191
 192         if (newline && !newline[1])
 193                 *newline = 0;
 194 }
 195
 196
 197 #define parse_err(fmt, args...) do {    \
 198         pr_err(fmt , ## args);  \
 199         return 1;               \
 200 } while (0)
 201
 202 #ifndef MODULE
 203 static int phram_init_called;
 204 /*
 205  * This shall contain the module parameter if any. It is of the form:
 206  * - phram=<device>,<address>,<size> for module case
 207  * - phram.phram=<device>,<address>,<size> for built-in case
 208  * We leave 64 bytes for the device name, 20 for the address and 20 for the
 209  * size.
 210  * Example: phram.phram=rootfs,0xa0000000,512Mi
 211  */
 212 static char phram_paramline[64 + 20 + 20];
 213 #endif
 214
 215 static int phram_setup(const char *val)
 216 {
 217         char buf[64 + 20 + 20], *str = buf;
 218         char *token[3];
 219         char *name;
 220         uint64_t start;
 221         uint64_t len;
 222         int i, ret;
 223
 224         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 225                 parse_err("parameter too long\n");
 226
 227         strcpy(str, val);
 228         kill_final_newline(str);
 229
 230         for (i = 0; i < 3; i++)
 231                 token[i] = strsep(&str, ",");
 232
 233         if (str)
 234                 parse_err("too many arguments\n");
 235
 236         if (!token[2])
 237                 parse_err("not enough arguments\n");
 238
 239         ret = parse_name(&name, token[0]);
 240         if (ret)
 241                 return ret;
 242
 243         ret = parse_num64(&start, token[1]);
 244         if (ret) {
 245                 kfree(name);
 246                 parse_err("illegal start address\n");
 247         }
 248
 249         ret = parse_num64(&len, token[2]);
 250         if (ret) {
 251                 kfree(name);
 252                 parse_err("illegal device length\n");
 253         }
 254
 255         ret = register_device(name, start, len);
 256         if (!ret)
 257                 pr_info("%s device: %#llx at %#llx\n", name, len, start);
 258         else
 259                 kfree(name);
 260
 261         return ret;
 262 }
 263
 264 static int phram_param_call(const char *val, const struct kernel_param *kp)
 265 {
 266 #ifdef MODULE
 267         return phram_setup(val);
 268 #else
 269         /*
 270          * If more parameters are later passed in via
 271          * /sys/module/phram/parameters/phram
 272          * and init_phram() has already been called,
 273          * we can parse the argument now.
 274          */
 275
 276         if (phram_init_called)
 277                 return phram_setup(val);
 278
 279         /*
 280          * During early boot stage, we only save the parameters
 281          * here. We must parse them later: if the param passed
 282          * from kernel boot command line, phram_param_call() is
 283          * called so early that it is not possible to resolve
 284          * the device (even kmalloc() fails). Defer that work to
 285          * phram_setup().
 286          */
 287
 288         if (strlen(val) >= sizeof(phram_paramline))
 289                 return -ENOSPC;
 290         strcpy(phram_paramline, val);
 291
 292         return 0;
 293 #endif
 294 }
 295
 296 module_param_call(phram, phram_param_call, NULL, NULL, 000);
 297 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 298
 299
 300 static int __init init_phram(void)
 301 {
 302         int ret = 0;
 303
 304 #ifndef MODULE
 305         if (phram_paramline[0])
 306                 ret = phram_setup(phram_paramline);
 307         phram_init_called = 1;
 308 #endif
 309
 310         return ret;
 311 }
 312
 313 static void __exit cleanup_phram(void)
 314 {
 315         unregister_devices();
 316 }
 317
 318 module_init(init_phram);
 319 module_exit(cleanup_phram);
 320
 321 MODULE_LICENSE("GPL");
 322 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
 323 MODULE_DESCRIPTION("MTD driver for physical RAM");