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 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         /*
  43          * This'll catch a few races. Free the thing before returning :)
  44          * I don't feel at all ashamed. This kind of thing is possible anyway
  45          * with flash, but unlikely.
  46          */
  47         instr->state = MTD_ERASE_DONE;
  48         mtd_erase_callback(instr);
  49         return 0;
  50 }
  51
  52 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  53                 size_t *retlen, void **virt, resource_size_t *phys)
  54 {
  55         *virt = mtd->priv + from;
  56         *retlen = len;
  57         return 0;
  58 }
  59
  60 static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  61 {
  62         return 0;
  63 }
  64
  65 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  66                 size_t *retlen, u_char *buf)
  67 {
  68         u_char *start = mtd->priv;
  69
  70         memcpy(buf, start + from, len);
  71         *retlen = len;
  72         return 0;
  73 }
  74
  75 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
  76                 size_t *retlen, const u_char *buf)
  77 {
  78         u_char *start = mtd->priv;
  79
  80         memcpy(start + to, buf, len);
  81         *retlen = len;
  82         return 0;
  83 }
  84
  85 static void unregister_devices(void)
  86 {
  87         struct phram_mtd_list *this, *safe;
  88
  89         list_for_each_entry_safe(this, safe, &phram_list, list) {
  90                 mtd_device_unregister(&this->mtd);
  91                 iounmap(this->mtd.priv);
  92                 kfree(this->mtd.name);
  93                 kfree(this);
  94         }
  95 }
  96
  97 static int register_device(char *name, unsigned long start, unsigned long len)
  98 {
  99         struct phram_mtd_list *new;
 100         int ret = -ENOMEM;
 101
 102         new = kzalloc(sizeof(*new), GFP_KERNEL);
 103         if (!new)
 104                 goto out0;
 105
 106         ret = -EIO;
 107         new->mtd.priv = ioremap(start, len);
 108         if (!new->mtd.priv) {
 109                 pr_err("ioremap failed\n");
 110                 goto out1;
 111         }
 112
 113
 114         new->mtd.name = name;
 115         new->mtd.size = len;
 116         new->mtd.flags = MTD_CAP_RAM;
 117         new->mtd._erase = phram_erase;
 118         new->mtd._point = phram_point;
 119         new->mtd._unpoint = phram_unpoint;
 120         new->mtd._read = phram_read;
 121         new->mtd._write = phram_write;
 122         new->mtd.owner = THIS_MODULE;
 123         new->mtd.type = MTD_RAM;
 124         new->mtd.erasesize = PAGE_SIZE;
 125         new->mtd.writesize = 1;
 126
 127         ret = -EAGAIN;
 128         if (mtd_device_register(&new->mtd, NULL, 0)) {
 129                 pr_err("Failed to register new device\n");
 130                 goto out2;
 131         }
 132
 133         list_add_tail(&new->list, &phram_list);
 134         return 0;
 135
 136 out2:
 137         iounmap(new->mtd.priv);
 138 out1:
 139         kfree(new);
 140 out0:
 141         return ret;
 142 }
 143
 144 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 145 {
 146         unsigned long result = simple_strtoul(cp, endp, base);
 147
 148         switch (**endp) {
 149         case 'G':
 150                 result *= 1024;
 151         case 'M':
 152                 result *= 1024;
 153         case 'k':
 154                 result *= 1024;
 155         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 156                 if ((*endp)[1] == 'i')
 157                         (*endp) += 2;
 158         }
 159         return result;
 160 }
 161
 162 static int parse_num32(uint32_t *num32, const char *token)
 163 {
 164         char *endp;
 165         unsigned long n;
 166
 167         n = ustrtoul(token, &endp, 0);
 168         if (*endp)
 169                 return -EINVAL;
 170
 171         *num32 = n;
 172         return 0;
 173 }
 174
 175 static int parse_name(char **pname, const char *token)
 176 {
 177         size_t len;
 178         char *name;
 179
 180         len = strlen(token) + 1;
 181         if (len > 64)
 182                 return -ENOSPC;
 183
 184         name = kmalloc(len, GFP_KERNEL);
 185         if (!name)
 186                 return -ENOMEM;
 187
 188         strcpy(name, token);
 189
 190         *pname = name;
 191         return 0;
 192 }
 193
 194
 195 static inline void kill_final_newline(char *str)
 196 {
 197         char *newline = strrchr(str, '\n');
 198         if (newline && !newline[1])
 199                 *newline = 0;
 200 }
 201
 202
 203 #define parse_err(fmt, args...) do {    \
 204         pr_err(fmt , ## args);  \
 205         return 1;               \
 206 } while (0)
 207
 208 /*
 209  * This shall contain the module parameter if any. It is of the form:
 210  * - phram=<device>,<address>,<size> for module case
 211  * - phram.phram=<device>,<address>,<size> for built-in case
 212  * We leave 64 bytes for the device name, 12 for the address and 12 for the
 213  * size.
 214  * Example: phram.phram=rootfs,0xa0000000,512Mi
 215  */
 216 static __initdata char phram_paramline[64+12+12];
 217
 218 static int __init phram_setup(const char *val)
 219 {
 220         char buf[64+12+12], *str = buf;
 221         char *token[3];
 222         char *name;
 223         uint32_t start;
 224         uint32_t len;
 225         int i, ret;
 226
 227         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 228                 parse_err("parameter too long\n");
 229
 230         strcpy(str, val);
 231         kill_final_newline(str);
 232
 233         for (i=0; i<3; i++)
 234                 token[i] = strsep(&str, ",");
 235
 236         if (str)
 237                 parse_err("too many arguments\n");
 238
 239         if (!token[2])
 240                 parse_err("not enough arguments\n");
 241
 242         ret = parse_name(&name, token[0]);
 243         if (ret)
 244                 return ret;
 245
 246         ret = parse_num32(&start, token[1]);
 247         if (ret) {
 248                 kfree(name);
 249                 parse_err("illegal start address\n");
 250         }
 251
 252         ret = parse_num32(&len, token[2]);
 253         if (ret) {
 254                 kfree(name);
 255                 parse_err("illegal device length\n");
 256         }
 257
 258         ret = register_device(name, start, len);
 259         if (!ret)
 260                 pr_info("%s device: %#x at %#x\n", name, len, start);
 261         else
 262                 kfree(name);
 263
 264         return ret;
 265 }
 266
 267 static int __init phram_param_call(const char *val, struct kernel_param *kp)
 268 {
 269         /*
 270          * This function is always called before 'init_phram()', whether
 271          * built-in or module.
 272          */
 273         if (strlen(val) >= sizeof(phram_paramline))
 274                 return -ENOSPC;
 275         strcpy(phram_paramline, val);
 276
 277         return 0;
 278 }
 279
 280 module_param_call(phram, phram_param_call, NULL, NULL, 000);
 281 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 282
 283
 284 static int __init init_phram(void)
 285 {
 286         if (phram_paramline[0])
 287                 return phram_setup(phram_paramline);
 288
 289         return 0;
 290 }
 291
 292 static void __exit cleanup_phram(void)
 293 {
 294         unregister_devices();
 295 }
 296
 297 module_init(init_phram);
 298 module_exit(cleanup_phram);
 299
 300 MODULE_LICENSE("GPL");
 301 MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
 302 MODULE_DESCRIPTION("MTD driver for physical RAM");