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 #include <asm/io.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/list.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/slab.h>
  24 #include <linux/mtd/mtd.h>
  25
  26 #define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args)
  27
  28 struct phram_mtd_list {
  29         struct mtd_info mtd;
  30         struct list_head list;
  31 };
  32
  33 static LIST_HEAD(phram_list);
  34
  35
  36 static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
  37 {
  38         u_char *start = mtd->priv;
  39
  40         if (instr->addr + instr->len > mtd->size)
  41                 return -EINVAL;
  42
  43         memset(start + instr->addr, 0xff, instr->len);
  44
  45         /* This'll catch a few races. Free the thing before returning :)
  46          * I don't feel at all ashamed. This kind of thing is possible anyway
  47          * with flash, but unlikely.
  48          */
  49
  50         instr->state = MTD_ERASE_DONE;
  51
  52         mtd_erase_callback(instr);
  53
  54         return 0;
  55 }
  56
  57 static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
  58                 size_t *retlen, void **virt, resource_size_t *phys)
  59 {
  60         if (from + len > mtd->size)
  61                 return -EINVAL;
  62
  63         /* can we return a physical address with this driver? */
  64         if (phys)
  65                 return -EINVAL;
  66
  67         *virt = mtd->priv + from;
  68         *retlen = len;
  69         return 0;
  70 }
  71
  72 static void phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  73 {
  74 }
  75
  76 static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
  77                 size_t *retlen, u_char *buf)
  78 {
  79         u_char *start = mtd->priv;
  80
  81         if (from >= mtd->size)
  82                 return -EINVAL;
  83
  84         if (len > mtd->size - from)
  85                 len = mtd->size - from;
  86
  87         memcpy(buf, start + from, len);
  88
  89         *retlen = len;
  90         return 0;
  91 }
  92
  93 static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
  94                 size_t *retlen, const u_char *buf)
  95 {
  96         u_char *start = mtd->priv;
  97
  98         if (to >= mtd->size)
  99                 return -EINVAL;
 100
 101         if (len > mtd->size - to)
 102                 len = mtd->size - to;
 103
 104         memcpy(start + to, buf, len);
 105
 106         *retlen = len;
 107         return 0;
 108 }
 109
 110
 111
 112 static void unregister_devices(void)
 113 {
 114         struct phram_mtd_list *this, *safe;
 115
 116         list_for_each_entry_safe(this, safe, &phram_list, list) {
 117                 del_mtd_device(&this->mtd);
 118                 iounmap(this->mtd.priv);
 119                 kfree(this);
 120         }
 121 }
 122
 123 static int register_device(char *name, unsigned long start, unsigned long len)
 124 {
 125         struct phram_mtd_list *new;
 126         int ret = -ENOMEM;
 127
 128         new = kzalloc(sizeof(*new), GFP_KERNEL);
 129         if (!new)
 130                 goto out0;
 131
 132         ret = -EIO;
 133         new->mtd.priv = ioremap(start, len);
 134         if (!new->mtd.priv) {
 135                 ERROR("ioremap failed\n");
 136                 goto out1;
 137         }
 138
 139
 140         new->mtd.name = name;
 141         new->mtd.size = len;
 142         new->mtd.flags = MTD_CAP_RAM;
 143         new->mtd.erase = phram_erase;
 144         new->mtd.point = phram_point;
 145         new->mtd.unpoint = phram_unpoint;
 146         new->mtd.read = phram_read;
 147         new->mtd.write = phram_write;
 148         new->mtd.owner = THIS_MODULE;
 149         new->mtd.type = MTD_RAM;
 150         new->mtd.erasesize = PAGE_SIZE;
 151         new->mtd.writesize = 1;
 152
 153         ret = -EAGAIN;
 154         if (add_mtd_device(&new->mtd)) {
 155                 ERROR("Failed to register new device\n");
 156                 goto out2;
 157         }
 158
 159         list_add_tail(&new->list, &phram_list);
 160         return 0;
 161
 162 out2:
 163         iounmap(new->mtd.priv);
 164 out1:
 165         kfree(new);
 166 out0:
 167         return ret;
 168 }
 169
 170 static int ustrtoul(const char *cp, char **endp, unsigned int base)
 171 {
 172         unsigned long result = simple_strtoul(cp, endp, base);
 173
 174         switch (**endp) {
 175         case 'G':
 176                 result *= 1024;
 177         case 'M':
 178                 result *= 1024;
 179         case 'k':
 180                 result *= 1024;
 181         /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
 182                 if ((*endp)[1] == 'i')
 183                         (*endp) += 2;
 184         }
 185         return result;
 186 }
 187
 188 static int parse_num32(uint32_t *num32, const char *token)
 189 {
 190         char *endp;
 191         unsigned long n;
 192
 193         n = ustrtoul(token, &endp, 0);
 194         if (*endp)
 195                 return -EINVAL;
 196
 197         *num32 = n;
 198         return 0;
 199 }
 200
 201 static int parse_name(char **pname, const char *token)
 202 {
 203         size_t len;
 204         char *name;
 205
 206         len = strlen(token) + 1;
 207         if (len > 64)
 208                 return -ENOSPC;
 209
 210         name = kmalloc(len, GFP_KERNEL);
 211         if (!name)
 212                 return -ENOMEM;
 213
 214         strcpy(name, token);
 215
 216         *pname = name;
 217         return 0;
 218 }
 219
 220
 221 static inline void kill_final_newline(char *str)
 222 {
 223         char *newline = strrchr(str, '\n');
 224         if (newline && !newline[1])
 225                 *newline = 0;
 226 }
 227
 228
 229 #define parse_err(fmt, args...) do {    \
 230         ERROR(fmt , ## args);   \
 231         return 0;               \
 232 } while (0)
 233
 234 static int phram_setup(const char *val, struct kernel_param *kp)
 235 {
 236         char buf[64+12+12], *str = buf;
 237         char *token[3];
 238         char *name;
 239         uint32_t start;
 240         uint32_t len;
 241         int i, ret;
 242
 243         if (strnlen(val, sizeof(buf)) >= sizeof(buf))
 244                 parse_err("parameter too long\n");
 245
 246         strcpy(str, val);
 247         kill_final_newline(str);
 248
 249         for (i=0; i<3; i++)
 250                 token[i] = strsep(&str, ",");
 251
 252         if (str)
 253                 parse_err("too many arguments\n");
 254
 255         if (!token[2])
 256                 parse_err("not enough arguments\n");
 257
 258         ret = parse_name(&name, token[0]);
 259         if (ret == -ENOMEM)
 260                 parse_err("out of memory\n");
 261         if (ret == -ENOSPC)
 262                 parse_err("name too long\n");
 263         if (ret)
 264                 return 0;
 265
 266         ret = parse_num32(&start, token[1]);
 267         if (ret) {
 268                 kfree(name);
 269                 parse_err("illegal start address\n");
 270         }
 271
 272         ret = parse_num32(&len, token[2]);
 273         if (ret) {
 274                 kfree(name);
 275                 parse_err("illegal device length\n");
 276         }
 277
 278         register_device(name, start, len);
 279
 280         return 0;
 281 }
 282
 283 module_param_call(phram, phram_setup, NULL, NULL, 000);
 284 MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 285
 286
 287 static int __init init_phram(void)
 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");