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