mtdcore.c revision 97894cda5773e59bd13e87b72077751099419a9f 
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#ifdef CONFIG_PROC_FS
23#include <linux/proc_fs.h>
24#endif
25
26#include <linux/mtd/mtd.h>
27
28/* These are exported solely for the purpose of mtd_blkdevs.c. You
29   should not use them for _anything_ else */
30DECLARE_MUTEX(mtd_table_mutex);
31struct mtd_info *mtd_table[MAX_MTD_DEVICES];
32
33EXPORT_SYMBOL_GPL(mtd_table_mutex);
34EXPORT_SYMBOL_GPL(mtd_table);
35
36static LIST_HEAD(mtd_notifiers);
37
38/**
39 *	add_mtd_device - register an MTD device
40 *	@mtd: pointer to new MTD device info structure
41 *
42 *	Add a device to the list of MTD devices present in the system, and
43 *	notify each currently active MTD 'user' of its arrival. Returns
44 *	zero on success or 1 on failure, which currently will only happen
45 *	if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
46 */
47
48int add_mtd_device(struct mtd_info *mtd)
49{
50	int i;
51
52	down(&mtd_table_mutex);
53
54	for (i=0; i < MAX_MTD_DEVICES; i++)
55		if (!mtd_table[i]) {
56			struct list_head *this;
57
58			mtd_table[i] = mtd;
59			mtd->index = i;
60			mtd->usecount = 0;
61
62			DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
63			/* No need to get a refcount on the module containing
64			   the notifier, since we hold the mtd_table_mutex */
65			list_for_each(this, &mtd_notifiers) {
66				struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
67				not->add(mtd);
68			}
69
70			up(&mtd_table_mutex);
71			/* We _know_ we aren't being removed, because
72			   our caller is still holding us here. So none
73			   of this try_ nonsense, and no bitching about it
74			   either. :) */
75			__module_get(THIS_MODULE);
76			return 0;
77		}
78
79	up(&mtd_table_mutex);
80	return 1;
81}
82
83/**
84 *	del_mtd_device - unregister an MTD device
85 *	@mtd: pointer to MTD device info structure
86 *
87 *	Remove a device from the list of MTD devices present in the system,
88 *	and notify each currently active MTD 'user' of its departure.
89 *	Returns zero on success or 1 on failure, which currently will happen
90 *	if the requested device does not appear to be present in the list.
91 */
92
93int del_mtd_device (struct mtd_info *mtd)
94{
95	int ret;
96
97	down(&mtd_table_mutex);
98
99	if (mtd_table[mtd->index] != mtd) {
100		ret = -ENODEV;
101	} else if (mtd->usecount) {
102		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
103		       mtd->index, mtd->name, mtd->usecount);
104		ret = -EBUSY;
105	} else {
106		struct list_head *this;
107
108		/* No need to get a refcount on the module containing
109		   the notifier, since we hold the mtd_table_mutex */
110		list_for_each(this, &mtd_notifiers) {
111			struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
112			not->remove(mtd);
113		}
114
115		mtd_table[mtd->index] = NULL;
116
117		module_put(THIS_MODULE);
118		ret = 0;
119	}
120
121	up(&mtd_table_mutex);
122	return ret;
123}
124
125/**
126 *	register_mtd_user - register a 'user' of MTD devices.
127 *	@new: pointer to notifier info structure
128 *
129 *	Registers a pair of callbacks function to be called upon addition
130 *	or removal of MTD devices. Causes the 'add' callback to be immediately
131 *	invoked for each MTD device currently present in the system.
132 */
133
134void register_mtd_user (struct mtd_notifier *new)
135{
136	int i;
137
138	down(&mtd_table_mutex);
139
140	list_add(&new->list, &mtd_notifiers);
141
142 	__module_get(THIS_MODULE);
143
144	for (i=0; i< MAX_MTD_DEVICES; i++)
145		if (mtd_table[i])
146			new->add(mtd_table[i]);
147
148	up(&mtd_table_mutex);
149}
150
151/**
152 *	unregister_mtd_user - unregister a 'user' of MTD devices.
153 *	@old: pointer to notifier info structure
154 *
155 *	Removes a callback function pair from the list of 'users' to be
156 *	notified upon addition or removal of MTD devices. Causes the
157 *	'remove' callback to be immediately invoked for each MTD device
158 *	currently present in the system.
159 */
160
161int unregister_mtd_user (struct mtd_notifier *old)
162{
163	int i;
164
165	down(&mtd_table_mutex);
166
167	module_put(THIS_MODULE);
168
169	for (i=0; i< MAX_MTD_DEVICES; i++)
170		if (mtd_table[i])
171			old->remove(mtd_table[i]);
172
173	list_del(&old->list);
174	up(&mtd_table_mutex);
175	return 0;
176}
177
178
179/**
180 *	get_mtd_device - obtain a validated handle for an MTD device
181 *	@mtd: last known address of the required MTD device
182 *	@num: internal device number of the required MTD device
183 *
184 *	Given a number and NULL address, return the num'th entry in the device
185 *	table, if any.	Given an address and num == -1, search the device table
186 *	for a device with that address and return if it's still present. Given
187 *	both, return the num'th driver only if its address matches. Return NULL
188 *	if not.
189 */
190
191struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
192{
193	struct mtd_info *ret = NULL;
194	int i;
195
196	down(&mtd_table_mutex);
197
198	if (num == -1) {
199		for (i=0; i< MAX_MTD_DEVICES; i++)
200			if (mtd_table[i] == mtd)
201				ret = mtd_table[i];
202	} else if (num < MAX_MTD_DEVICES) {
203		ret = mtd_table[num];
204		if (mtd && mtd != ret)
205			ret = NULL;
206	}
207
208	if (ret && !try_module_get(ret->owner))
209		ret = NULL;
210
211	if (ret)
212		ret->usecount++;
213
214	up(&mtd_table_mutex);
215	return ret;
216}
217
218void put_mtd_device(struct mtd_info *mtd)
219{
220	int c;
221
222	down(&mtd_table_mutex);
223	c = --mtd->usecount;
224	up(&mtd_table_mutex);
225	BUG_ON(c < 0);
226
227	module_put(mtd->owner);
228}
229
230/* default_mtd_writev - default mtd writev method for MTD devices that
231 *			dont implement their own
232 */
233
234int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
235		       unsigned long count, loff_t to, size_t *retlen)
236{
237	unsigned long i;
238	size_t totlen = 0, thislen;
239	int ret = 0;
240
241	if(!mtd->write) {
242		ret = -EROFS;
243	} else {
244		for (i=0; i<count; i++) {
245			if (!vecs[i].iov_len)
246				continue;
247			ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
248			totlen += thislen;
249			if (ret || thislen != vecs[i].iov_len)
250				break;
251			to += vecs[i].iov_len;
252		}
253	}
254	if (retlen)
255		*retlen = totlen;
256	return ret;
257}
258
259
260/* default_mtd_readv - default mtd readv method for MTD devices that dont
261 *		       implement their own
262 */
263
264int default_mtd_readv(struct mtd_info *mtd, struct kvec *vecs,
265		      unsigned long count, loff_t from, size_t *retlen)
266{
267	unsigned long i;
268	size_t totlen = 0, thislen;
269	int ret = 0;
270
271	if(!mtd->read) {
272		ret = -EIO;
273	} else {
274		for (i=0; i<count; i++) {
275			if (!vecs[i].iov_len)
276				continue;
277			ret = mtd->read(mtd, from, vecs[i].iov_len, &thislen, vecs[i].iov_base);
278			totlen += thislen;
279			if (ret || thislen != vecs[i].iov_len)
280				break;
281			from += vecs[i].iov_len;
282		}
283	}
284	if (retlen)
285		*retlen = totlen;
286	return ret;
287}
288
289
290EXPORT_SYMBOL(add_mtd_device);
291EXPORT_SYMBOL(del_mtd_device);
292EXPORT_SYMBOL(get_mtd_device);
293EXPORT_SYMBOL(put_mtd_device);
294EXPORT_SYMBOL(register_mtd_user);
295EXPORT_SYMBOL(unregister_mtd_user);
296EXPORT_SYMBOL(default_mtd_writev);
297EXPORT_SYMBOL(default_mtd_readv);
298
299/*====================================================================*/
300/* Support for /proc/mtd */
301
302#ifdef CONFIG_PROC_FS
303static struct proc_dir_entry *proc_mtd;
304
305static inline int mtd_proc_info (char *buf, int i)
306{
307	struct mtd_info *this = mtd_table[i];
308
309	if (!this)
310		return 0;
311
312	return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
313		       this->erasesize, this->name);
314}
315
316static int mtd_read_proc (char *page, char **start, off_t off, int count,
317			  int *eof, void *data_unused)
318{
319	int len, l, i;
320        off_t   begin = 0;
321
322	down(&mtd_table_mutex);
323
324	len = sprintf(page, "dev:    size   erasesize  name\n");
325        for (i=0; i< MAX_MTD_DEVICES; i++) {
326
327                l = mtd_proc_info(page + len, i);
328                len += l;
329                if (len+begin > off+count)
330                        goto done;
331                if (len+begin < off) {
332                        begin += len;
333                        len = 0;
334                }
335        }
336
337        *eof = 1;
338
339done:
340	up(&mtd_table_mutex);
341        if (off >= len+begin)
342                return 0;
343        *start = page + (off-begin);
344        return ((count < begin+len-off) ? count : begin+len-off);
345}
346
347#endif /* CONFIG_PROC_FS */
348
349/*====================================================================*/
350/* Init code */
351
352static int __init init_mtd(void)
353{
354#ifdef CONFIG_PROC_FS
355	if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
356		proc_mtd->read_proc = mtd_read_proc;
357#endif
358	return 0;
359}
360
361static void __exit cleanup_mtd(void)
362{
363#ifdef CONFIG_PROC_FS
364        if (proc_mtd)
365		remove_proc_entry( "mtd", NULL);
366#endif
367}
368
369module_init(init_mtd);
370module_exit(cleanup_mtd);
371
372
373MODULE_LICENSE("GPL");
374MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
375MODULE_DESCRIPTION("Core MTD registration and access routines");
376