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
add_mtd_device(struct mtd_info * mtd)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
del_mtd_device(struct mtd_info * mtd)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
register_mtd_user(struct mtd_notifier * new)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
unregister_mtd_user(struct mtd_notifier * old)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
get_mtd_device(struct mtd_info * mtd,int num)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
get_mtd_device_nm(const char * name)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
put_mtd_device(struct mtd_info * mtd)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
default_mtd_writev(struct mtd_info * mtd,const struct kvec * vecs,unsigned long count,loff_t to,size_t * retlen)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
mtd_proc_info(char * buf,int i)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
mtd_read_proc(char * page,char ** start,off_t off,int count,int * eof,void * data_unused)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
init_mtd(void)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
cleanup_mtd(void)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