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"); 349