drivers/mtd/mtdcore.c

   1 /*
   2  * Core registration and callback routines for MTD
   3  * drivers and users.
   4  *
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/kernel.h>
   9 #include <linux/ptrace.h>
  10 #include <linux/slab.h>
  11 #include <linux/string.h>
  12 #include <linux/timer.h>
  13 #include <linux/major.h>
  14 #include <linux/fs.h>
  15 #include <linux/err.h>
  16 #include <linux/ioctl.h>
  17 #include <linux/init.h>
  18 #include <linux/mtd/compatmac.h>
  19 #include <linux/proc_fs.h>
  20
  21 #include <linux/mtd/mtd.h>
  22
  23 #include "mtdcore.h"
  24
  25 /* These are exported solely for the purpose of mtd_blkdevs.c. You
  26    should not use them for _anything_ else */
  27 DEFINE_MUTEX(mtd_table_mutex);
  28 struct mtd_info *mtd_table[MAX_MTD_DEVICES];
  29
  30 EXPORT_SYMBOL_GPL(mtd_table_mutex);
  31 EXPORT_SYMBOL_GPL(mtd_table);
  32
  33 static LIST_HEAD(mtd_notifiers);
  34
  35 /**
  36  *      add_mtd_device - register an MTD device
  37  *      @mtd: pointer to new MTD device info structure
  38  *
  39  *      Add a device to the list of MTD devices present in the system, and
  40  *      notify each currently active MTD 'user' of its arrival. Returns
  41  *      zero on success or 1 on failure, which currently will only happen
  42  *      if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
  43  */
  44
  45 int add_mtd_device(struct mtd_info *mtd)
  46 {
  47         int i;
  48
  49         BUG_ON(mtd->writesize == 0);
  50         mutex_lock(&mtd_table_mutex);
  51
  52         for (i=0; i < MAX_MTD_DEVICES; i++)
  53                 if (!mtd_table[i]) {
  54                         struct mtd_notifier *not;
  55
  56                         mtd_table[i] = mtd;
  57                         mtd->index = i;
  58                         mtd->usecount = 0;
  59
  60                         if (is_power_of_2(mtd->erasesize))
  61                                 mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
  62                         else
  63                                 mtd->erasesize_shift = 0;
  64
  65                         if (is_power_of_2(mtd->writesize))
  66                                 mtd->writesize_shift = ffs(mtd->writesize) - 1;
  67                         else
  68                                 mtd->writesize_shift = 0;
  69
  70                         mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
  71                         mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
  72
  73                         /* Some chips always power up locked. Unlock them now */
  74                         if ((mtd->flags & MTD_WRITEABLE)
  75                             && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
  76                                 if (mtd->unlock(mtd, 0, mtd->size))
  77                                         printk(KERN_WARNING
  78                                                "%s: unlock failed, "
  79                                                "writes may not work\n",
  80                                                mtd->name);
  81                         }
  82
  83                         DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
  84                         /* No need to get a refcount on the module containing
  85                            the notifier, since we hold the mtd_table_mutex */
  86                         list_for_each_entry(not, &mtd_notifiers, list)
  87                                 not->add(mtd);
  88
  89                         mutex_unlock(&mtd_table_mutex);
  90                         /* We _know_ we aren't being removed, because
  91                            our caller is still holding us here. So none
  92                            of this try_ nonsense, and no bitching about it
  93                            either. :) */
  94                         __module_get(THIS_MODULE);
  95                         return 0;
  96                 }
  97
  98         mutex_unlock(&mtd_table_mutex);
  99         return 1;
 100 }
 101
 102 /**
 103  *      del_mtd_device - unregister an MTD device
 104  *      @mtd: pointer to MTD device info structure
 105  *
 106  *      Remove a device from the list of MTD devices present in the system,
 107  *      and notify each currently active MTD 'user' of its departure.
 108  *      Returns zero on success or 1 on failure, which currently will happen
 109  *      if the requested device does not appear to be present in the list.
 110  */
 111
 112 int del_mtd_device (struct mtd_info *mtd)
 113 {
 114         int ret;
 115
 116         mutex_lock(&mtd_table_mutex);
 117
 118         if (mtd_table[mtd->index] != mtd) {
 119                 ret = -ENODEV;
 120         } else if (mtd->usecount) {
 121                 printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 122                        mtd->index, mtd->name, mtd->usecount);
 123                 ret = -EBUSY;
 124         } else {
 125                 struct mtd_notifier *not;
 126
 127                 /* No need to get a refcount on the module containing
 128                    the notifier, since we hold the mtd_table_mutex */
 129                 list_for_each_entry(not, &mtd_notifiers, list)
 130                         not->remove(mtd);
 131
 132                 mtd_table[mtd->index] = NULL;
 133
 134                 module_put(THIS_MODULE);
 135                 ret = 0;
 136         }
 137
 138         mutex_unlock(&mtd_table_mutex);
 139         return ret;
 140 }
 141
 142 /**
 143  *      register_mtd_user - register a 'user' of MTD devices.
 144  *      @new: pointer to notifier info structure
 145  *
 146  *      Registers a pair of callbacks function to be called upon addition
 147  *      or removal of MTD devices. Causes the 'add' callback to be immediately
 148  *      invoked for each MTD device currently present in the system.
 149  */
 150
 151 void register_mtd_user (struct mtd_notifier *new)
 152 {
 153         int i;
 154
 155         mutex_lock(&mtd_table_mutex);
 156
 157         list_add(&new->list, &mtd_notifiers);
 158
 159         __module_get(THIS_MODULE);
 160
 161         for (i=0; i< MAX_MTD_DEVICES; i++)
 162                 if (mtd_table[i])
 163                         new->add(mtd_table[i]);
 164
 165         mutex_unlock(&mtd_table_mutex);
 166 }
 167
 168 /**
 169  *      unregister_mtd_user - unregister a 'user' of MTD devices.
 170  *      @old: pointer to notifier info structure
 171  *
 172  *      Removes a callback function pair from the list of 'users' to be
 173  *      notified upon addition or removal of MTD devices. Causes the
 174  *      'remove' callback to be immediately invoked for each MTD device
 175  *      currently present in the system.
 176  */
 177
 178 int unregister_mtd_user (struct mtd_notifier *old)
 179 {
 180         int i;
 181
 182         mutex_lock(&mtd_table_mutex);
 183
 184         module_put(THIS_MODULE);
 185
 186         for (i=0; i< MAX_MTD_DEVICES; i++)
 187                 if (mtd_table[i])
 188                         old->remove(mtd_table[i]);
 189
 190         list_del(&old->list);
 191         mutex_unlock(&mtd_table_mutex);
 192         return 0;
 193 }
 194
 195
 196 /**
 197  *      get_mtd_device - obtain a validated handle for an MTD device
 198  *      @mtd: last known address of the required MTD device
 199  *      @num: internal device number of the required MTD device
 200  *
 201  *      Given a number and NULL address, return the num'th entry in the device
 202  *      table, if any.  Given an address and num == -1, search the device table
 203  *      for a device with that address and return if it's still present. Given
 204  *      both, return the num'th driver only if its address matches. Return
 205  *      error code if not.
 206  */
 207
 208 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 209 {
 210         struct mtd_info *ret = NULL;
 211         int i, err = -ENODEV;
 212
 213         mutex_lock(&mtd_table_mutex);
 214
 215         if (num == -1) {
 216                 for (i=0; i< MAX_MTD_DEVICES; i++)
 217                         if (mtd_table[i] == mtd)
 218                                 ret = mtd_table[i];
 219         } else if (num < MAX_MTD_DEVICES) {
 220                 ret = mtd_table[num];
 221                 if (mtd && mtd != ret)
 222                         ret = NULL;
 223         }
 224
 225         if (!ret)
 226                 goto out_unlock;
 227
 228         if (!try_module_get(ret->owner))
 229                 goto out_unlock;
 230
 231         if (ret->get_device) {
 232                 err = ret->get_device(ret);
 233                 if (err)
 234                         goto out_put;
 235         }
 236
 237         ret->usecount++;
 238         mutex_unlock(&mtd_table_mutex);
 239         return ret;
 240
 241 out_put:
 242         module_put(ret->owner);
 243 out_unlock:
 244         mutex_unlock(&mtd_table_mutex);
 245         return ERR_PTR(err);
 246 }
 247
 248 /**
 249  *      get_mtd_device_nm - obtain a validated handle for an MTD device by
 250  *      device name
 251  *      @name: MTD device name to open
 252  *
 253  *      This function returns MTD device description structure in case of
 254  *      success and an error code in case of failure.
 255  */
 256
 257 struct mtd_info *get_mtd_device_nm(const char *name)
 258 {
 259         int i, err = -ENODEV;
 260         struct mtd_info *mtd = NULL;
 261
 262         mutex_lock(&mtd_table_mutex);
 263
 264         for (i = 0; i < MAX_MTD_DEVICES; i++) {
 265                 if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
 266                         mtd = mtd_table[i];
 267                         break;
 268                 }
 269         }
 270
 271         if (!mtd)
 272                 goto out_unlock;
 273
 274         if (!try_module_get(mtd->owner))
 275                 goto out_unlock;
 276
 277         if (mtd->get_device) {
 278                 err = mtd->get_device(mtd);
 279                 if (err)
 280                         goto out_put;
 281         }
 282
 283         mtd->usecount++;
 284         mutex_unlock(&mtd_table_mutex);
 285         return mtd;
 286
 287 out_put:
 288         module_put(mtd->owner);
 289 out_unlock:
 290         mutex_unlock(&mtd_table_mutex);
 291         return ERR_PTR(err);
 292 }
 293
 294 void put_mtd_device(struct mtd_info *mtd)
 295 {
 296         int c;
 297
 298         mutex_lock(&mtd_table_mutex);
 299         c = --mtd->usecount;
 300         if (mtd->put_device)
 301                 mtd->put_device(mtd);
 302         mutex_unlock(&mtd_table_mutex);
 303         BUG_ON(c < 0);
 304
 305         module_put(mtd->owner);
 306 }
 307
 308 /* default_mtd_writev - default mtd writev method for MTD devices that
 309  *                      don't implement their own
 310  */
 311
 312 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
 313                        unsigned long count, loff_t to, size_t *retlen)
 314 {
 315         unsigned long i;
 316         size_t totlen = 0, thislen;
 317         int ret = 0;
 318
 319         if(!mtd->write) {
 320                 ret = -EROFS;
 321         } else {
 322                 for (i=0; i<count; i++) {
 323                         if (!vecs[i].iov_len)
 324                                 continue;
 325                         ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
 326                         totlen += thislen;
 327                         if (ret || thislen != vecs[i].iov_len)
 328                                 break;
 329                         to += vecs[i].iov_len;
 330                 }
 331         }
 332         if (retlen)
 333                 *retlen = totlen;
 334         return ret;
 335 }
 336
 337 EXPORT_SYMBOL_GPL(add_mtd_device);
 338 EXPORT_SYMBOL_GPL(del_mtd_device);
 339 EXPORT_SYMBOL_GPL(get_mtd_device);
 340 EXPORT_SYMBOL_GPL(get_mtd_device_nm);
 341 EXPORT_SYMBOL_GPL(put_mtd_device);
 342 EXPORT_SYMBOL_GPL(register_mtd_user);
 343 EXPORT_SYMBOL_GPL(unregister_mtd_user);
 344 EXPORT_SYMBOL_GPL(default_mtd_writev);
 345
 346 #ifdef CONFIG_PROC_FS
 347
 348 /*====================================================================*/
 349 /* Support for /proc/mtd */
 350
 351 static struct proc_dir_entry *proc_mtd;
 352
 353 static inline int mtd_proc_info (char *buf, int i)
 354 {
 355         struct mtd_info *this = mtd_table[i];
 356
 357         if (!this)
 358                 return 0;
 359
 360         return sprintf(buf, "mtd%d: %8.8llx %8.8x \"%s\"\n", i,
 361                        (unsigned long long)this->size,
 362                        this->erasesize, this->name);
 363 }
 364
 365 static int mtd_read_proc (char *page, char **start, off_t off, int count,
 366                           int *eof, void *data_unused)
 367 {
 368         int len, l, i;
 369         off_t   begin = 0;
 370
 371         mutex_lock(&mtd_table_mutex);
 372
 373         len = sprintf(page, "dev:    size   erasesize  name\n");
 374         for (i=0; i< MAX_MTD_DEVICES; i++) {
 375
 376                 l = mtd_proc_info(page + len, i);
 377                 len += l;
 378                 if (len+begin > off+count)
 379                         goto done;
 380                 if (len+begin < off) {
 381                         begin += len;
 382                         len = 0;
 383                 }
 384         }
 385
 386         *eof = 1;
 387
 388 done:
 389         mutex_unlock(&mtd_table_mutex);
 390         if (off >= len+begin)
 391                 return 0;
 392         *start = page + (off-begin);
 393         return ((count < begin+len-off) ? count : begin+len-off);
 394 }
 395
 396 /*====================================================================*/
 397 /* Init code */
 398
 399 static int __init init_mtd(void)
 400 {
 401         if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
 402                 proc_mtd->read_proc = mtd_read_proc;
 403         return 0;
 404 }
 405
 406 static void __exit cleanup_mtd(void)
 407 {
 408         if (proc_mtd)
 409                 remove_proc_entry( "mtd", NULL);
 410 }
 411
 412 module_init(init_mtd);
 413 module_exit(cleanup_mtd);
 414
 415 #endif /* CONFIG_PROC_FS */
 416
 417
 418 MODULE_LICENSE("GPL");
 419 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 420 MODULE_DESCRIPTION("Core MTD registration and access routines");