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"); 421