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 #include <linux/proc_fs.h> 23 24 #include <linux/mtd/mtd.h> 25 26 /* These are exported solely for the purpose of mtd_blkdevs.c. You 27 should not use them for _anything_ else */ 28 DEFINE_MUTEX(mtd_table_mutex); 29 struct mtd_info *mtd_table[MAX_MTD_DEVICES]; 30 31 EXPORT_SYMBOL_GPL(mtd_table_mutex); 32 EXPORT_SYMBOL_GPL(mtd_table); 33 34 static LIST_HEAD(mtd_notifiers); 35 36 /** 37 * add_mtd_device - register an MTD device 38 * @mtd: pointer to new MTD device info structure 39 * 40 * Add a device to the list of MTD devices present in the system, and 41 * notify each currently active MTD 'user' of its arrival. Returns 42 * zero on success or 1 on failure, which currently will only happen 43 * if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16) 44 */ 45 46 int add_mtd_device(struct mtd_info *mtd) 47 { 48 int i; 49 50 BUG_ON(mtd->writesize == 0); 51 mutex_lock(&mtd_table_mutex); 52 53 for (i=0; i < MAX_MTD_DEVICES; i++) 54 if (!mtd_table[i]) { 55 struct list_head *this; 56 57 mtd_table[i] = mtd; 58 mtd->index = i; 59 mtd->usecount = 0; 60 61 DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name); 62 /* No need to get a refcount on the module containing 63 the notifier, since we hold the mtd_table_mutex */ 64 list_for_each(this, &mtd_notifiers) { 65 struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list); 66 not->add(mtd); 67 } 68 69 mutex_unlock(&mtd_table_mutex); 70 /* We _know_ we aren't being removed, because 71 our caller is still holding us here. So none 72 of this try_ nonsense, and no bitching about it 73 either. :) */ 74 __module_get(THIS_MODULE); 75 return 0; 76 } 77 78 mutex_unlock(&mtd_table_mutex); 79 return 1; 80 } 81 82 /** 83 * del_mtd_device - unregister an MTD device 84 * @mtd: pointer to MTD device info structure 85 * 86 * Remove a device from the list of MTD devices present in the system, 87 * and notify each currently active MTD 'user' of its departure. 88 * Returns zero on success or 1 on failure, which currently will happen 89 * if the requested device does not appear to be present in the list. 90 */ 91 92 int del_mtd_device (struct mtd_info *mtd) 93 { 94 int ret; 95 96 mutex_lock(&mtd_table_mutex); 97 98 if (mtd_table[mtd->index] != mtd) { 99 ret = -ENODEV; 100 } else if (mtd->usecount) { 101 printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n", 102 mtd->index, mtd->name, mtd->usecount); 103 ret = -EBUSY; 104 } else { 105 struct list_head *this; 106 107 /* No need to get a refcount on the module containing 108 the notifier, since we hold the mtd_table_mutex */ 109 list_for_each(this, &mtd_notifiers) { 110 struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list); 111 not->remove(mtd); 112 } 113 114 mtd_table[mtd->index] = NULL; 115 116 module_put(THIS_MODULE); 117 ret = 0; 118 } 119 120 mutex_unlock(&mtd_table_mutex); 121 return ret; 122 } 123 124 /** 125 * register_mtd_user - register a 'user' of MTD devices. 126 * @new: pointer to notifier info structure 127 * 128 * Registers a pair of callbacks function to be called upon addition 129 * or removal of MTD devices. Causes the 'add' callback to be immediately 130 * invoked for each MTD device currently present in the system. 131 */ 132 133 void register_mtd_user (struct mtd_notifier *new) 134 { 135 int i; 136 137 mutex_lock(&mtd_table_mutex); 138 139 list_add(&new->list, &mtd_notifiers); 140 141 __module_get(THIS_MODULE); 142 143 for (i=0; i< MAX_MTD_DEVICES; i++) 144 if (mtd_table[i]) 145 new->add(mtd_table[i]); 146 147 mutex_unlock(&mtd_table_mutex); 148 } 149 150 /** 151 * unregister_mtd_user - unregister a 'user' of MTD devices. 152 * @old: pointer to notifier info structure 153 * 154 * Removes a callback function pair from the list of 'users' to be 155 * notified upon addition or removal of MTD devices. Causes the 156 * 'remove' callback to be immediately invoked for each MTD device 157 * currently present in the system. 158 */ 159 160 int unregister_mtd_user (struct mtd_notifier *old) 161 { 162 int i; 163 164 mutex_lock(&mtd_table_mutex); 165 166 module_put(THIS_MODULE); 167 168 for (i=0; i< MAX_MTD_DEVICES; i++) 169 if (mtd_table[i]) 170 old->remove(mtd_table[i]); 171 172 list_del(&old->list); 173 mutex_unlock(&mtd_table_mutex); 174 return 0; 175 } 176 177 178 /** 179 * get_mtd_device - obtain a validated handle for an MTD device 180 * @mtd: last known address of the required MTD device 181 * @num: internal device number of the required MTD device 182 * 183 * Given a number and NULL address, return the num'th entry in the device 184 * table, if any. Given an address and num == -1, search the device table 185 * for a device with that address and return if it's still present. Given 186 * both, return the num'th driver only if its address matches. Return NULL 187 * if not. 188 */ 189 190 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num) 191 { 192 struct mtd_info *ret = NULL; 193 int i; 194 195 mutex_lock(&mtd_table_mutex); 196 197 if (num == -1) { 198 for (i=0; i< MAX_MTD_DEVICES; i++) 199 if (mtd_table[i] == mtd) 200 ret = mtd_table[i]; 201 } else if (num < MAX_MTD_DEVICES) { 202 ret = mtd_table[num]; 203 if (mtd && mtd != ret) 204 ret = NULL; 205 } 206 207 if (ret && !try_module_get(ret->owner)) 208 ret = NULL; 209 210 if (ret) 211 ret->usecount++; 212 213 mutex_unlock(&mtd_table_mutex); 214 return ret; 215 } 216 217 void put_mtd_device(struct mtd_info *mtd) 218 { 219 int c; 220 221 mutex_lock(&mtd_table_mutex); 222 c = --mtd->usecount; 223 mutex_unlock(&mtd_table_mutex); 224 BUG_ON(c < 0); 225 226 module_put(mtd->owner); 227 } 228 229 /* default_mtd_writev - default mtd writev method for MTD devices that 230 * dont implement their own 231 */ 232 233 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs, 234 unsigned long count, loff_t to, size_t *retlen) 235 { 236 unsigned long i; 237 size_t totlen = 0, thislen; 238 int ret = 0; 239 240 if(!mtd->write) { 241 ret = -EROFS; 242 } else { 243 for (i=0; i<count; i++) { 244 if (!vecs[i].iov_len) 245 continue; 246 ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base); 247 totlen += thislen; 248 if (ret || thislen != vecs[i].iov_len) 249 break; 250 to += vecs[i].iov_len; 251 } 252 } 253 if (retlen) 254 *retlen = totlen; 255 return ret; 256 } 257 258 EXPORT_SYMBOL(add_mtd_device); 259 EXPORT_SYMBOL(del_mtd_device); 260 EXPORT_SYMBOL(get_mtd_device); 261 EXPORT_SYMBOL(put_mtd_device); 262 EXPORT_SYMBOL(register_mtd_user); 263 EXPORT_SYMBOL(unregister_mtd_user); 264 EXPORT_SYMBOL(default_mtd_writev); 265 266 #ifdef CONFIG_PROC_FS 267 268 /*====================================================================*/ 269 /* Support for /proc/mtd */ 270 271 static struct proc_dir_entry *proc_mtd; 272 273 static inline int mtd_proc_info (char *buf, int i) 274 { 275 struct mtd_info *this = mtd_table[i]; 276 277 if (!this) 278 return 0; 279 280 return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size, 281 this->erasesize, this->name); 282 } 283 284 static int mtd_read_proc (char *page, char **start, off_t off, int count, 285 int *eof, void *data_unused) 286 { 287 int len, l, i; 288 off_t begin = 0; 289 290 mutex_lock(&mtd_table_mutex); 291 292 len = sprintf(page, "dev: size erasesize name\n"); 293 for (i=0; i< MAX_MTD_DEVICES; i++) { 294 295 l = mtd_proc_info(page + len, i); 296 len += l; 297 if (len+begin > off+count) 298 goto done; 299 if (len+begin < off) { 300 begin += len; 301 len = 0; 302 } 303 } 304 305 *eof = 1; 306 307 done: 308 mutex_unlock(&mtd_table_mutex); 309 if (off >= len+begin) 310 return 0; 311 *start = page + (off-begin); 312 return ((count < begin+len-off) ? count : begin+len-off); 313 } 314 315 /*====================================================================*/ 316 /* Init code */ 317 318 static int __init init_mtd(void) 319 { 320 if ((proc_mtd = create_proc_entry( "mtd", 0, NULL ))) 321 proc_mtd->read_proc = mtd_read_proc; 322 return 0; 323 } 324 325 static void __exit cleanup_mtd(void) 326 { 327 if (proc_mtd) 328 remove_proc_entry( "mtd", NULL); 329 } 330 331 module_init(init_mtd); 332 module_exit(cleanup_mtd); 333 334 #endif /* CONFIG_PROC_FS */ 335 336 337 MODULE_LICENSE("GPL"); 338 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 339 MODULE_DESCRIPTION("Core MTD registration and access routines"); 340