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/sched.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/timer.h>
  16 #include <linux/major.h>
  17 #include <linux/fs.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 /* 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 list_head *this;
  55
  56                         mtd_table[i] = mtd;
  57                         mtd->index = i;
  58                         mtd->usecount = 0;
  59
  60                         /* Some chips always power up locked. Unlock them now */
  61                         if ((mtd->flags & MTD_WRITEABLE)
  62                             && (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {
  63                                 if (mtd->unlock(mtd, 0, mtd->size))
  64                                         printk(KERN_WARNING
  65                                                "%s: unlock failed, "
  66                                                "writes may not work\n",
  67                                                mtd->name);
  68                         }
  69
  70                         DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
  71                         /* No need to get a refcount on the module containing
  72                            the notifier, since we hold the mtd_table_mutex */
  73                         list_for_each(this, &mtd_notifiers) {
  74                                 struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
  75                                 not->add(mtd);
  76                         }
  77
  78                         mutex_unlock(&mtd_table_mutex);
  79                         /* We _know_ we aren't being removed, because
  80                            our caller is still holding us here. So none
  81                            of this try_ nonsense, and no bitching about it
  82                            either. :) */
  83                         __module_get(THIS_MODULE);
  84                         return 0;
  85                 }
  86
  87         mutex_unlock(&mtd_table_mutex);
  88         return 1;
  89 }
  90
  91 /**
  92  *      del_mtd_device - unregister an MTD device
  93  *      @mtd: pointer to MTD device info structure
  94  *
  95  *      Remove a device from the list of MTD devices present in the system,
  96  *      and notify each currently active MTD 'user' of its departure.
  97  *      Returns zero on success or 1 on failure, which currently will happen
  98  *      if the requested device does not appear to be present in the list.
  99  */
 100
 101 int del_mtd_device (struct mtd_info *mtd)
 102 {
 103         int ret;
 104
 105         mutex_lock(&mtd_table_mutex);
 106
 107         if (mtd_table[mtd->index] != mtd) {
 108                 ret = -ENODEV;
 109         } else if (mtd->usecount) {
 110                 printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 111                        mtd->index, mtd->name, mtd->usecount);
 112                 ret = -EBUSY;
 113         } else {
 114                 struct list_head *this;
 115
 116                 /* No need to get a refcount on the module containing
 117                    the notifier, since we hold the mtd_table_mutex */
 118                 list_for_each(this, &mtd_notifiers) {
 119                         struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
 120                         not->remove(mtd);
 121                 }
 122
 123                 mtd_table[mtd->index] = NULL;
 124
 125                 module_put(THIS_MODULE);
 126                 ret = 0;
 127         }
 128
 129         mutex_unlock(&mtd_table_mutex);
 130         return ret;
 131 }
 132
 133 /**
 134  *      register_mtd_user - register a 'user' of MTD devices.
 135  *      @new: pointer to notifier info structure
 136  *
 137  *      Registers a pair of callbacks function to be called upon addition
 138  *      or removal of MTD devices. Causes the 'add' callback to be immediately
 139  *      invoked for each MTD device currently present in the system.
 140  */
 141
 142 void register_mtd_user (struct mtd_notifier *new)
 143 {
 144         int i;
 145
 146         mutex_lock(&mtd_table_mutex);
 147
 148         list_add(&new->list, &mtd_notifiers);
 149
 150         __module_get(THIS_MODULE);
 151
 152         for (i=0; i< MAX_MTD_DEVICES; i++)
 153                 if (mtd_table[i])
 154                         new->add(mtd_table[i]);
 155
 156         mutex_unlock(&mtd_table_mutex);
 157 }
 158
 159 /**
 160  *      unregister_mtd_user - unregister a 'user' of MTD devices.
 161  *      @old: pointer to notifier info structure
 162  *
 163  *      Removes a callback function pair from the list of 'users' to be
 164  *      notified upon addition or removal of MTD devices. Causes the
 165  *      'remove' callback to be immediately invoked for each MTD device
 166  *      currently present in the system.
 167  */
 168
 169 int unregister_mtd_user (struct mtd_notifier *old)
 170 {
 171         int i;
 172
 173         mutex_lock(&mtd_table_mutex);
 174
 175         module_put(THIS_MODULE);
 176
 177         for (i=0; i< MAX_MTD_DEVICES; i++)
 178                 if (mtd_table[i])
 179                         old->remove(mtd_table[i]);
 180
 181         list_del(&old->list);
 182         mutex_unlock(&mtd_table_mutex);
 183         return 0;
 184 }
 185
 186
 187 /**
 188  *      get_mtd_device - obtain a validated handle for an MTD device
 189  *      @mtd: last known address of the required MTD device
 190  *      @num: internal device number of the required MTD device
 191  *
 192  *      Given a number and NULL address, return the num'th entry in the device
 193  *      table, if any.  Given an address and num == -1, search the device table
 194  *      for a device with that address and return if it's still present. Given
 195  *      both, return the num'th driver only if its address matches. Return NULL
 196  *      if not.
 197  */
 198
 199 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 200 {
 201         struct mtd_info *ret = NULL;
 202         int i;
 203
 204         mutex_lock(&mtd_table_mutex);
 205
 206         if (num == -1) {
 207                 for (i=0; i< MAX_MTD_DEVICES; i++)
 208                         if (mtd_table[i] == mtd)
 209                                 ret = mtd_table[i];
 210         } else if (num < MAX_MTD_DEVICES) {
 211                 ret = mtd_table[num];
 212                 if (mtd && mtd != ret)
 213                         ret = NULL;
 214         }
 215
 216         if (ret && !try_module_get(ret->owner))
 217                 ret = NULL;
 218
 219         if (ret)
 220                 ret->usecount++;
 221
 222         mutex_unlock(&mtd_table_mutex);
 223         return ret;
 224 }
 225
 226 void put_mtd_device(struct mtd_info *mtd)
 227 {
 228         int c;
 229
 230         mutex_lock(&mtd_table_mutex);
 231         c = --mtd->usecount;
 232         mutex_unlock(&mtd_table_mutex);
 233         BUG_ON(c < 0);
 234
 235         module_put(mtd->owner);
 236 }
 237
 238 /* default_mtd_writev - default mtd writev method for MTD devices that
 239  *                      dont implement their own
 240  */
 241
 242 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
 243                        unsigned long count, loff_t to, size_t *retlen)
 244 {
 245         unsigned long i;
 246         size_t totlen = 0, thislen;
 247         int ret = 0;
 248
 249         if(!mtd->write) {
 250                 ret = -EROFS;
 251         } else {
 252                 for (i=0; i<count; i++) {
 253                         if (!vecs[i].iov_len)
 254                                 continue;
 255                         ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
 256                         totlen += thislen;
 257                         if (ret || thislen != vecs[i].iov_len)
 258                                 break;
 259                         to += vecs[i].iov_len;
 260                 }
 261         }
 262         if (retlen)
 263                 *retlen = totlen;
 264         return ret;
 265 }
 266
 267 EXPORT_SYMBOL(add_mtd_device);
 268 EXPORT_SYMBOL(del_mtd_device);
 269 EXPORT_SYMBOL(get_mtd_device);
 270 EXPORT_SYMBOL(put_mtd_device);
 271 EXPORT_SYMBOL(register_mtd_user);
 272 EXPORT_SYMBOL(unregister_mtd_user);
 273 EXPORT_SYMBOL(default_mtd_writev);
 274
 275 #ifdef CONFIG_PROC_FS
 276
 277 /*====================================================================*/
 278 /* Support for /proc/mtd */
 279
 280 static struct proc_dir_entry *proc_mtd;
 281
 282 static inline int mtd_proc_info (char *buf, int i)
 283 {
 284         struct mtd_info *this = mtd_table[i];
 285
 286         if (!this)
 287                 return 0;
 288
 289         return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
 290                        this->erasesize, this->name);
 291 }
 292
 293 static int mtd_read_proc (char *page, char **start, off_t off, int count,
 294                           int *eof, void *data_unused)
 295 {
 296         int len, l, i;
 297         off_t   begin = 0;
 298
 299         mutex_lock(&mtd_table_mutex);
 300
 301         len = sprintf(page, "dev:    size   erasesize  name\n");
 302         for (i=0; i< MAX_MTD_DEVICES; i++) {
 303
 304                 l = mtd_proc_info(page + len, i);
 305                 len += l;
 306                 if (len+begin > off+count)
 307                         goto done;
 308                 if (len+begin < off) {
 309                         begin += len;
 310                         len = 0;
 311                 }
 312         }
 313
 314         *eof = 1;
 315
 316 done:
 317         mutex_unlock(&mtd_table_mutex);
 318         if (off >= len+begin)
 319                 return 0;
 320         *start = page + (off-begin);
 321         return ((count < begin+len-off) ? count : begin+len-off);
 322 }
 323
 324 /*====================================================================*/
 325 /* Init code */
 326
 327 static int __init init_mtd(void)
 328 {
 329         if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
 330                 proc_mtd->read_proc = mtd_read_proc;
 331         return 0;
 332 }
 333
 334 static void __exit cleanup_mtd(void)
 335 {
 336         if (proc_mtd)
 337                 remove_proc_entry( "mtd", NULL);
 338 }
 339
 340 module_init(init_mtd);
 341 module_exit(cleanup_mtd);
 342
 343 #endif /* CONFIG_PROC_FS */
 344
 345
 346 MODULE_LICENSE("GPL");
 347 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 348 MODULE_DESCRIPTION("Core MTD registration and access routines");