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                         case 'M':
 151                                 shift += 10;
 152                         case 'k':
 153                                 shift += 10;
 154                                 token[len - 2] = 0;
 155                                 break;
 156                         default:
 157                                 return -EINVAL;
 158                         }
 159                 }
 160         }
 161
 162         ret = kstrtou64(token, 0, num64);
 163         *num64 <<= shift;
 164
 165         return ret;
 166 }
 167
 168 static int parse_name(char **pname, const char *token)
 169 {
 170         size_t len;
 171         char *name;
 172
 173         len = strlen(token) + 1;
 174         if (len > 64)
 175                 return -ENOSPC;
 176
 177         name = kstrdup(token, GFP_KERNEL);
 178         if (!name)
 179                 return -ENOMEM;
 180
 181         *pname = name;
 182         return 0;
 183 }
 184
 185
 186 static inline void kill_final_newline(char *str)
 187 {
 188         char *newline = strrchr(str, '\n');
 189
 190         if (newline && !newline[1])
 191                 *newline = 0;
 192 }
 193
 194
 195 #define parse_err(fmt, args...) do {    \
 196         pr_err(fmt , ## args);  \
 197         return 1;               \
 198 } while (0)
 199
 200 #ifndef MODULE
 201 static int phram_init_called;
 202 /*
 203  * This shall contain the module parameter if any. It is of the form:
 204  * - phram=<device>,<address>,<size> for module case
 205  * - phram.phram=<device>,<address>,<size> for built-in case
 206  * We leave 64 bytes for the device name, 20 for the address and 20 for the
 207  * size.
 208  * Example: phram.phram=rootfs,0xa0000000,512Mi
 209  */
 210 static char phram_paramline[64 + 20 + 20];
 211 #endif
 212
 213 static int phram_setup(const char *val)
 214 {
 215         char buf[64 + 20 + 20], *str = buf;
 216         char *token[3];
 217         char *name;
 218         uint64_t start;
 219         uint64_t len;
 220         int i, ret;
 221
 222         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 223                 parse_err("parameter too long\n");
 224
 225         strcpy(str, val);
 226         kill_final_newline(str);
 227
 228         for (i = 0; i < 3; i++)
 229                 token[i] = strsep(&str, ",");
 230
 231         if (str)
 232                 parse_err("too many arguments\n");
 233
 234         if (!token[2])
 235                 parse_err("not enough arguments\n");
 236
 237         ret = parse_name(&name, token[0]);
 238         if (ret)
 239                 return ret;
 240
 241         ret = parse_num64(&start, token[1]);
 242         if (ret) {
 243                 kfree(name);
 244                 parse_err("illegal start address\n");
 245         }
 246
 247         ret = parse_num64(&len, token[2]);
 248         if (ret) {
 249                 kfree(name);
 250                 parse_err("illegal device length\n");
 251         }
 252
 253         ret = register_device(name, start, len);
 254         if (!ret)
 255                 pr_info("%s device: %#llx at %#llx\n", name, len, start);
 256         else
 257                 kfree(name);
 258
 259         return ret;
 260 }
 261
 262 static int phram_param_call(const char *val, const struct kernel_param *kp)
 263 {
 264 #ifdef MODULE
 265         return phram_setup(val);
 266 #else
 267         /*
 268          * If more parameters are later passed in via
 269          * /sys/module/phram/parameters/phram
 270          * and init_phram() has already been called,
 271          * we can parse the argument now.
 272          */
 273
 274         if (phram_init_called)
 275                 return phram_setup(val);
 276
 277         /*
 278          * During early boot stage, we only save the parameters
 279          * here. We must parse them later: if the param passed
 280          * from kernel boot command line, phram_param_call() is
 281          * called so early that it is not possible to resolve
 282          * the device (even kmalloc() fails). Defer that work to
 283          * phram_setup().
 284          */
 285
 286         if (strlen(val) >= sizeof(phram_paramline))
 287                 return -ENOSPC;
 288         strcpy(phram_paramline, val);
 289
 290         return 0;
 291 #endif
 292 }
 293
 294 module_param_call(phram, phram_param_call, NULL, NULL, 000);
 295 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 296
 297
 298 static int __init init_phram(void)
 299 {
 300         int ret = 0;
 301
 302 #ifndef MODULE
 303         if (phram_paramline[0])
 304                 ret = phram_setup(phram_paramline);
 305         phram_init_called = 1;
 306 #endif
 307
 308         return ret;
 309 }
 310
 311 static void __exit cleanup_phram(void)
 312 {
 313         unregister_devices();
 314 }
 315
 316 module_init(init_phram);
 317 module_exit(cleanup_phram);
 318
 319 MODULE_LICENSE("GPL");
 320 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
 321 MODULE_DESCRIPTION("MTD driver for physical RAM");