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 /* 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 196 * error code 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, err = -ENODEV; 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) 217 goto out_unlock; 218 219 if (!try_module_get(ret->owner)) 220 goto out_unlock; 221 222 if (ret->get_device) { 223 err = ret->get_device(ret); 224 if (err) 225 goto out_put; 226 } 227 228 ret->usecount++; 229 mutex_unlock(&mtd_table_mutex); 230 return ret; 231 232 out_put: 233 module_put(ret->owner); 234 out_unlock: 235 mutex_unlock(&mtd_table_mutex); 236 return ERR_PTR(err); 237 } 238 239 /** 240 * get_mtd_device_nm - obtain a validated handle for an MTD device by 241 * device name 242 * @name: MTD device name to open 243 * 244 * This function returns MTD device description structure in case of 245 * success and an error code in case of failure. 246 */ 247 248 struct mtd_info *get_mtd_device_nm(const char *name) 249 { 250 int i, err = -ENODEV; 251 struct mtd_info *mtd = NULL; 252 253 mutex_lock(&mtd_table_mutex); 254 255 for (i = 0; i < MAX_MTD_DEVICES; i++) { 256 if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) { 257 mtd = mtd_table[i]; 258 break; 259 } 260 } 261 262 if (!mtd) 263 goto out_unlock; 264 265 if (!try_module_get(mtd->owner)) 266 goto out_unlock; 267 268 if (mtd->get_device) { 269 err = mtd->get_device(mtd); 270 if (err) 271 goto out_put; 272 } 273 274 mtd->usecount++; 275 mutex_unlock(&mtd_table_mutex); 276 return mtd; 277 278 out_put: 279 module_put(mtd->owner); 280 out_unlock: 281 mutex_unlock(&mtd_table_mutex); 282 return ERR_PTR(err); 283 } 284 285 void put_mtd_device(struct mtd_info *mtd) 286 { 287 int c; 288 289 mutex_lock(&mtd_table_mutex); 290 c = --mtd->usecount; 291 if (mtd->put_device) 292 mtd->put_device(mtd); 293 mutex_unlock(&mtd_table_mutex); 294 BUG_ON(c < 0); 295 296 module_put(mtd->owner); 297 } 298 299 /* default_mtd_writev - default mtd writev method for MTD devices that 300 * don't implement their own 301 */ 302 303 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs, 304 unsigned long count, loff_t to, size_t *retlen) 305 { 306 unsigned long i; 307 size_t totlen = 0, thislen; 308 int ret = 0; 309 310 if(!mtd->write) { 311 ret = -EROFS; 312 } else { 313 for (i=0; i<count; i++) { 314 if (!vecs[i].iov_len) 315 continue; 316 ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base); 317 totlen += thislen; 318 if (ret || thislen != vecs[i].iov_len) 319 break; 320 to += vecs[i].iov_len; 321 } 322 } 323 if (retlen) 324 *retlen = totlen; 325 return ret; 326 } 327 328 EXPORT_SYMBOL_GPL(add_mtd_device); 329 EXPORT_SYMBOL_GPL(del_mtd_device); 330 EXPORT_SYMBOL_GPL(get_mtd_device); 331 EXPORT_SYMBOL_GPL(get_mtd_device_nm); 332 EXPORT_SYMBOL_GPL(put_mtd_device); 333 EXPORT_SYMBOL_GPL(register_mtd_user); 334 EXPORT_SYMBOL_GPL(unregister_mtd_user); 335 EXPORT_SYMBOL_GPL(default_mtd_writev); 336 337 #ifdef CONFIG_PROC_FS 338 339 /*====================================================================*/ 340 /* Support for /proc/mtd */ 341 342 static struct proc_dir_entry *proc_mtd; 343 344 static inline int mtd_proc_info (char *buf, int i) 345 { 346 struct mtd_info *this = mtd_table[i]; 347 348 if (!this) 349 return 0; 350 351 return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size, 352 this->erasesize, this->name); 353 } 354 355 static int mtd_read_proc (char *page, char **start, off_t off, int count, 356 int *eof, void *data_unused) 357 { 358 int len, l, i; 359 off_t begin = 0; 360 361 mutex_lock(&mtd_table_mutex); 362 363 len = sprintf(page, "dev: size erasesize name\n"); 364 for (i=0; i< MAX_MTD_DEVICES; i++) { 365 366 l = mtd_proc_info(page + len, i); 367 len += l; 368 if (len+begin > off+count) 369 goto done; 370 if (len+begin < off) { 371 begin += len; 372 len = 0; 373 } 374 } 375 376 *eof = 1; 377 378 done: 379 mutex_unlock(&mtd_table_mutex); 380 if (off >= len+begin) 381 return 0; 382 *start = page + (off-begin); 383 return ((count < begin+len-off) ? count : begin+len-off); 384 } 385 386 /*====================================================================*/ 387 /* Init code */ 388 389 static int __init init_mtd(void) 390 { 391 if ((proc_mtd = create_proc_entry( "mtd", 0, NULL ))) 392 proc_mtd->read_proc = mtd_read_proc; 393 return 0; 394 } 395 396 static void __exit cleanup_mtd(void) 397 { 398 if (proc_mtd) 399 remove_proc_entry( "mtd", NULL); 400 } 401 402 module_init(init_mtd); 403 module_exit(cleanup_mtd); 404 405 #endif /* CONFIG_PROC_FS */ 406 407 408 MODULE_LICENSE("GPL"); 409 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 410 MODULE_DESCRIPTION("Core MTD registration and access routines"); 411