2 * $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
4 * Core registration and callback routines for MTD
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>
19 #include <linux/ioctl.h>
20 #include <linux/init.h>
21 #include <linux/mtd/compatmac.h>
22 #include <linux/proc_fs.h>
24 #include <linux/mtd/mtd.h>
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];
31 EXPORT_SYMBOL_GPL(mtd_table_mutex);
32 EXPORT_SYMBOL_GPL(mtd_table);
34 static LIST_HEAD(mtd_notifiers);
37 * add_mtd_device - register an MTD device
38 * @mtd: pointer to new MTD device info structure
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)
46 int add_mtd_device(struct mtd_info *mtd)
50 BUG_ON(mtd->writesize == 0);
51 mutex_lock(&mtd_table_mutex);
53 for (i=0; i < MAX_MTD_DEVICES; i++)
55 struct list_head *this;
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);
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
74 __module_get(THIS_MODULE);
78 mutex_unlock(&mtd_table_mutex);
83 * del_mtd_device - unregister an MTD device
84 * @mtd: pointer to MTD device info structure
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.
92 int del_mtd_device (struct mtd_info *mtd)
96 mutex_lock(&mtd_table_mutex);
98 if (mtd_table[mtd->index] != mtd) {
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);
105 struct list_head *this;
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);
114 mtd_table[mtd->index] = NULL;
116 module_put(THIS_MODULE);
120 mutex_unlock(&mtd_table_mutex);
125 * register_mtd_user - register a 'user' of MTD devices.
126 * @new: pointer to notifier info structure
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.
133 void register_mtd_user (struct mtd_notifier *new)
137 mutex_lock(&mtd_table_mutex);
139 list_add(&new->list, &mtd_notifiers);
141 __module_get(THIS_MODULE);
143 for (i=0; i< MAX_MTD_DEVICES; i++)
145 new->add(mtd_table[i]);
147 mutex_unlock(&mtd_table_mutex);
151 * unregister_mtd_user - unregister a 'user' of MTD devices.
152 * @old: pointer to notifier info structure
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.
160 int unregister_mtd_user (struct mtd_notifier *old)
164 mutex_lock(&mtd_table_mutex);
166 module_put(THIS_MODULE);
168 for (i=0; i< MAX_MTD_DEVICES; i++)
170 old->remove(mtd_table[i]);
172 list_del(&old->list);
173 mutex_unlock(&mtd_table_mutex);
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
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
190 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
192 struct mtd_info *ret = NULL;
195 mutex_lock(&mtd_table_mutex);
198 for (i=0; i< MAX_MTD_DEVICES; i++)
199 if (mtd_table[i] == mtd)
201 } else if (num < MAX_MTD_DEVICES) {
202 ret = mtd_table[num];
203 if (mtd && mtd != ret)
207 if (ret && !try_module_get(ret->owner))
213 mutex_unlock(&mtd_table_mutex);
217 void put_mtd_device(struct mtd_info *mtd)
221 mutex_lock(&mtd_table_mutex);
223 mutex_unlock(&mtd_table_mutex);
226 module_put(mtd->owner);
229 /* default_mtd_writev - default mtd writev method for MTD devices that
230 * dont implement their own
233 int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
234 unsigned long count, loff_t to, size_t *retlen)
237 size_t totlen = 0, thislen;
243 for (i=0; i<count; i++) {
244 if (!vecs[i].iov_len)
246 ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
248 if (ret || thislen != vecs[i].iov_len)
250 to += vecs[i].iov_len;
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);
266 #ifdef CONFIG_PROC_FS
268 /*====================================================================*/
269 /* Support for /proc/mtd */
271 static struct proc_dir_entry *proc_mtd;
273 static inline int mtd_proc_info (char *buf, int i)
275 struct mtd_info *this = mtd_table[i];
280 return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
281 this->erasesize, this->name);
284 static int mtd_read_proc (char *page, char **start, off_t off, int count,
285 int *eof, void *data_unused)
290 mutex_lock(&mtd_table_mutex);
292 len = sprintf(page, "dev: size erasesize name\n");
293 for (i=0; i< MAX_MTD_DEVICES; i++) {
295 l = mtd_proc_info(page + len, i);
297 if (len+begin > off+count)
299 if (len+begin < off) {
308 mutex_unlock(&mtd_table_mutex);
309 if (off >= len+begin)
311 *start = page + (off-begin);
312 return ((count < begin+len-off) ? count : begin+len-off);
315 /*====================================================================*/
318 static int __init init_mtd(void)
320 if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
321 proc_mtd->read_proc = mtd_read_proc;
325 static void __exit cleanup_mtd(void)
328 remove_proc_entry( "mtd", NULL);
331 module_init(init_mtd);
332 module_exit(cleanup_mtd);
334 #endif /* CONFIG_PROC_FS */
337 MODULE_LICENSE("GPL");
338 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
339 MODULE_DESCRIPTION("Core MTD registration and access routines");