drivers/mtd/mtdcore.c

   1 /*
   2  * $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
   3  *
   4  * Core registration and callback routines for MTD
   5  * drivers and users.
   6  *
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/ptrace.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/timer.h>
  15 #include <linux/major.h>
  16 #include <linux/fs.h>
  17 #include <linux/err.h>
  18 #include <linux/ioctl.h>
  19 #include <linux/init.h>
  20 #include <linux/mtd/compatmac.h>
  21 #include <linux/proc_fs.h>
  22
  23 #include <linux/mtd/mtd.h>
  24
  25 #include "mtdcore.h"
  26
  27 /* These are exported solely for the purpose of mtd_blkdevs.c. You
  28    should not use them for _anything_ else */
  29 DEFINE_MUTEX(mtd_table_mutex);
  30 struct mtd_info *mtd_table[MAX_MTD_DEVICES];
  31
  32 EXPORT_SYMBOL_GPL(mtd_table_mutex);
  33 EXPORT_SYMBOL_GPL(mtd_table);
  34
  35 static LIST_HEAD(mtd_notifiers);
  36
  37 /**
  38  *      add_mtd_device - register an MTD device
  39  *      @mtd: pointer to new MTD device info structure
  40  *
  41  *      Add a device to the list of MTD devices present in the system, and
  42  *      notify each currently active MTD 'user' of its arrival. Returns
  43  *      zero on success or 1 on failure, which currently will only happen
  44  *      if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
  45  */
  46
  47 int add_mtd_device(struct mtd_info *mtd)
  48 {
  49         int i;
  50
  51         BUG_ON(mtd->writesize == 0);
  52         mutex_lock(&mtd_table_mutex);
  53
  54         for (i=0; i < MAX_MTD_DEVICES; i++)
  55                 if (!mtd_table[i]) {
  56                         struct list_head *this;
  57
  58                         mtd_table[i] = mtd;
  59                         mtd->index = i;
  60                         mtd->usecount = 0;
  61
  62                         /* Some chips always power up locked. Unlock them now */
  63                         if ((mtd->flags & MTD_WRITEABLE)
  64                             && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
  65                                 if (mtd->unlock(mtd, 0, mtd->size))
  66                                         printk(KERN_WARNING
  67                                                "%s: unlock failed, "
  68                                                "writes may not work\n",
  69                                                mtd->name);
  70                         }
  71
  72                         DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
  73                         /* No need to get a refcount on the module containing
  74                            the notifier, since we hold the mtd_table_mutex */
  75                         list_for_each(this, &mtd_notifiers) {
  76                                 struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
  77                                 not->add(mtd);
  78                         }
  79
  80                         mutex_unlock(&mtd_table_mutex);
  81                         /* We _know_ we aren't being removed, because
  82                            our caller is still holding us here. So none
  83                            of this try_ nonsense, and no bitching about it
  84                            either. :) */
  85                         __module_get(THIS_MODULE);
  86                         return 0;
  87                 }
  88
  89         mutex_unlock(&mtd_table_mutex);
  90         return 1;
  91 }
  92
  93 /**
  94  *      del_mtd_device - unregister an MTD device
  95  *      @mtd: pointer to MTD device info structure
  96  *
  97  *      Remove a device from the list of MTD devices present in the system,
  98  *      and notify each currently active MTD 'user' of its departure.
  99  *      Returns zero on success or 1 on failure, which currently will happen
 100  *      if the requested device does not appear to be present in the list.
 101  */
 102
 103 int del_mtd_device (struct mtd_info *mtd)
 104 {
 105         int ret;
 106
 107         mutex_lock(&mtd_table_mutex);
 108
 109         if (mtd_table[mtd->index] != mtd) {
 110                 ret = -ENODEV;
 111         } else if (mtd->usecount) {
 112                 printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 113                        mtd->index, mtd->name, mtd->usecount);
 114                 ret = -EBUSY;
 115         } else {
 116                 struct list_head *this;
 117
 118                 /* No need to get a refcount on the module containing
 119                    the notifier, since we hold the mtd_table_mutex */
 120                 list_for_each(this, &mtd_notifiers) {
 121                         struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
 122                         not->remove(mtd);
 123                 }
 124
 125                 mtd_table[mtd->index] = NULL;
 126
 127                 module_put(THIS_MODULE);
 128                 ret = 0;
 129         }
 130
 131         mutex_unlock(&mtd_table_mutex);
 132         return ret;
 133 }
 134
 135 /**
 136  *      register_mtd_user - register a 'user' of MTD devices.
 137  *      @new: pointer to notifier info structure
 138  *
 139  *      Registers a pair of callbacks function to be called upon addition
 140  *      or removal of MTD devices. Causes the 'add' callback to be immediately
 141  *      invoked for each MTD device currently present in the system.
 142  */
 143
 144 void register_mtd_user (struct mtd_notifier *new)
 145 {
 146         int i;
 147
 148         mutex_lock(&mtd_table_mutex);
 149
 150         list_add(&new->list, &mtd_notifiers);
 151
 152         __module_get(THIS_MODULE);
 153
 154         for (i=0; i< MAX_MTD_DEVICES; i++)
 155                 if (mtd_table[i])
 156                         new->add(mtd_table[i]);
 157
 158         mutex_unlock(&mtd_table_mutex);
 159 }
 160
 161 /**
 162  *      unregister_mtd_user - unregister a 'user' of MTD devices.
 163  *      @old: pointer to notifier info structure
 164  *
 165  *      Removes a callback function pair from the list of 'users' to be
 166  *      notified upon addition or removal of MTD devices. Causes the
 167  *      'remove' callback to be immediately invoked for each MTD device
 168  *      currently present in the system.
 169  */
 170
 171 int unregister_mtd_user (struct mtd_notifier *old)
 172 {
 173         int i;
 174
 175         mutex_lock(&mtd_table_mutex);
 176
 177         module_put(THIS_MODULE);
 178
 179         for (i=0; i< MAX_MTD_DEVICES; i++)
 180                 if (mtd_table[i])
 181                         old->remove(mtd_table[i]);
 182
 183         list_del(&old->list);
 184         mutex_unlock(&mtd_table_mutex);
 185         return 0;
 186 }
 187
 188
 189 /**
 190  *      get_mtd_device - obtain a validated handle for an MTD device
 191  *      @mtd: last known address of the required MTD device
 192  *      @num: internal device number of the required MTD device
 193  *
 194  *      Given a number and NULL address, return the num'th entry in the device
 195  *      table, if any.  Given an address and num == -1, search the device table
 196  *      for a device with that address and return if it's still present. Given
 197  *      both, return the num'th driver only if its address matches. Return
 198  *      error code if not.
 199  */
 200
 201 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 202 {
 203         struct mtd_info *ret = NULL;
 204         int i, err = -ENODEV;
 205
 206         mutex_lock(&mtd_table_mutex);
 207
 208         if (num == -1) {
 209                 for (i=0; i< MAX_MTD_DEVICES; i++)
 210                         if (mtd_table[i] == mtd)
 211                                 ret = mtd_table[i];
 212         } else if (num < MAX_MTD_DEVICES) {
 213                 ret = mtd_table[num];
 214                 if (mtd && mtd != ret)
 215                         ret = NULL;
 216         }
 217
 218         if (!ret)
 219                 goto out_unlock;
 220
 221         if (!try_module_get(ret->owner))
 222                 goto out_unlock;
 223
 224         if (ret->get_device) {
 225                 err = ret->get_device(ret);
 226                 if (err)
 227                         goto out_put;
 228         }
 229
 230         ret->usecount++;
 231         mutex_unlock(&mtd_table_mutex);
 232         return ret;
 233
 234 out_put:
 235         module_put(ret->owner);
 236 out_unlock:
 237         mutex_unlock(&mtd_table_mutex);
 238         return ERR_PTR(err);
 239 }
 240
 241 /**
 242  *      get_mtd_device_nm - obtain a validated handle for an MTD device by
 243  *      device name
 244  *      @name: MTD device name to open
 245  *
 246  *      This function returns MTD device description structure in case of
 247  *      success and an error code in case of failure.
 248  */
 249
 250 struct mtd_info *get_mtd_device_nm(const char *name)
 251 {
 252         int i, err = -ENODEV;
 253         struct mtd_info *mtd = NULL;
 254
 255         mutex_lock(&mtd_table_mutex);
 256
 257         for (i = 0; i < MAX_MTD_DEVICES; i++) {
 258                 if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
 259                         mtd = mtd_table[i];
 260                         break;
 261                 }
 262         }
 263
 264         if (!mtd)
 265                 goto out_unlock;
 266
 267         if (!try_module_get(mtd->owner))
 268                 goto out_unlock;
 269
 270         if (mtd->get_device) {
 271                 err = mtd->get_device(mtd);
 272                 if (err)
 273                         goto out_put;
 274         }
 275
 276         mtd->usecount++;
 277         mutex_unlock(&mtd_table_mutex);
 278         return mtd;
 279
 280 out_put:
 281         module_put(mtd->owner);
 282 out_unlock:
 283         mutex_unlock(&mtd_table_mutex);
 284         return ERR_PTR(err);
 285 }
 286
 287 void put_mtd_device(struct mtd_info *mtd)
 288 {
 289         int c;
 290
 291         mutex_lock(&mtd_table_mutex);
 292         c = --mtd->usecount;
 293         if (mtd->put_device)
 294                 mtd->put_device(mtd);
 295         mutex_unlock(&mtd_table_mutex);
 296         BUG_ON(c < 0);
 297
 298         module_put(mtd->owner);
 299 }
 300
 301 /* default_mtd_writev - default mtd writev method for MTD devices that
 302  *                      don't implement their own
 303  */
 304
 305 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
 306                        unsigned long count, loff_t to, size_t *retlen)
 307 {
 308         unsigned long i;
 309         size_t totlen = 0, thislen;
 310         int ret = 0;
 311
 312         if(!mtd->write) {
 313                 ret = -EROFS;
 314         } else {
 315                 for (i=0; i<count; i++) {
 316                         if (!vecs[i].iov_len)
 317                                 continue;
 318                         ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
 319                         totlen += thislen;
 320                         if (ret || thislen != vecs[i].iov_len)
 321                                 break;
 322                         to += vecs[i].iov_len;
 323                 }
 324         }
 325         if (retlen)
 326                 *retlen = totlen;
 327         return ret;
 328 }
 329
 330 EXPORT_SYMBOL_GPL(add_mtd_device);
 331 EXPORT_SYMBOL_GPL(del_mtd_device);
 332 EXPORT_SYMBOL_GPL(get_mtd_device);
 333 EXPORT_SYMBOL_GPL(get_mtd_device_nm);
 334 EXPORT_SYMBOL_GPL(put_mtd_device);
 335 EXPORT_SYMBOL_GPL(register_mtd_user);
 336 EXPORT_SYMBOL_GPL(unregister_mtd_user);
 337 EXPORT_SYMBOL_GPL(default_mtd_writev);
 338
 339 #ifdef CONFIG_PROC_FS
 340
 341 /*====================================================================*/
 342 /* Support for /proc/mtd */
 343
 344 static struct proc_dir_entry *proc_mtd;
 345
 346 static inline int mtd_proc_info (char *buf, int i)
 347 {
 348         struct mtd_info *this = mtd_table[i];
 349
 350         if (!this)
 351                 return 0;
 352
 353         return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
 354                        this->erasesize, this->name);
 355 }
 356
 357 static int mtd_read_proc (char *page, char **start, off_t off, int count,
 358                           int *eof, void *data_unused)
 359 {
 360         int len, l, i;
 361         off_t   begin = 0;
 362
 363         mutex_lock(&mtd_table_mutex);
 364
 365         len = sprintf(page, "dev:    size   erasesize  name\n");
 366         for (i=0; i< MAX_MTD_DEVICES; i++) {
 367
 368                 l = mtd_proc_info(page + len, i);
 369                 len += l;
 370                 if (len+begin > off+count)
 371                         goto done;
 372                 if (len+begin < off) {
 373                         begin += len;
 374                         len = 0;
 375                 }
 376         }
 377
 378         *eof = 1;
 379
 380 done:
 381         mutex_unlock(&mtd_table_mutex);
 382         if (off >= len+begin)
 383                 return 0;
 384         *start = page + (off-begin);
 385         return ((count < begin+len-off) ? count : begin+len-off);
 386 }
 387
 388 /*====================================================================*/
 389 /* Init code */
 390
 391 static int __init init_mtd(void)
 392 {
 393         if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
 394                 proc_mtd->read_proc = mtd_read_proc;
 395         return 0;
 396 }
 397
 398 static void __exit cleanup_mtd(void)
 399 {
 400         if (proc_mtd)
 401                 remove_proc_entry( "mtd", NULL);
 402 }
 403
 404 module_init(init_mtd);
 405 module_exit(cleanup_mtd);
 406
 407 #endif /* CONFIG_PROC_FS */
 408
 409
 410 MODULE_LICENSE("GPL");
 411 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 412 MODULE_DESCRIPTION("Core MTD registration and access routines");