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