1/*
2 * $Id: mtdcore.c,v 1.1.1.1 2007/08/03 18:52:43 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/ptrace.h>
12#include <linux/slab.h>
13#include <linux/string.h>
14#include <linux/timer.h>
15#include <linux/major.h>
16#include <linux/fs.h>
17#include <linux/err.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 */
27DEFINE_MUTEX(mtd_table_mutex);
28struct mtd_info *mtd_table[MAX_MTD_DEVICES];
29
30EXPORT_SYMBOL_GPL(mtd_table_mutex);
31EXPORT_SYMBOL_GPL(mtd_table);
32
33static 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
45int 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			/* Some chips always power up locked. Unlock them now */
61			if ((mtd->flags & MTD_WRITEABLE)
62			    && (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {
63				if (mtd->unlock(mtd, 0, mtd->size))
64					printk(KERN_WARNING
65					       "%s: unlock failed, "
66					       "writes may not work\n",
67					       mtd->name);
68			}
69
70			DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
71			/* No need to get a refcount on the module containing
72			   the notifier, since we hold the mtd_table_mutex */
73			list_for_each(this, &mtd_notifiers) {
74				struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
75				not->add(mtd);
76			}
77
78			mutex_unlock(&mtd_table_mutex);
79			/* We _know_ we aren't being removed, because
80			   our caller is still holding us here. So none
81			   of this try_ nonsense, and no bitching about it
82			   either. :) */
83			__module_get(THIS_MODULE);
84			return 0;
85		}
86
87	mutex_unlock(&mtd_table_mutex);
88	return 1;
89}
90
91/**
92 *	del_mtd_device - unregister an MTD device
93 *	@mtd: pointer to MTD device info structure
94 *
95 *	Remove a device from the list of MTD devices present in the system,
96 *	and notify each currently active MTD 'user' of its departure.
97 *	Returns zero on success or 1 on failure, which currently will happen
98 *	if the requested device does not appear to be present in the list.
99 */
100
101int del_mtd_device (struct mtd_info *mtd)
102{
103	int ret;
104
105	mutex_lock(&mtd_table_mutex);
106
107	if (mtd_table[mtd->index] != mtd) {
108		ret = -ENODEV;
109	} else if (mtd->usecount) {
110		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
111		       mtd->index, mtd->name, mtd->usecount);
112		ret = -EBUSY;
113	} else {
114		struct list_head *this;
115
116		/* No need to get a refcount on the module containing
117		   the notifier, since we hold the mtd_table_mutex */
118		list_for_each(this, &mtd_notifiers) {
119			struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
120			not->remove(mtd);
121		}
122
123		mtd_table[mtd->index] = NULL;
124
125		module_put(THIS_MODULE);
126		ret = 0;
127	}
128
129	mutex_unlock(&mtd_table_mutex);
130	return ret;
131}
132
133/**
134 *	register_mtd_user - register a 'user' of MTD devices.
135 *	@new: pointer to notifier info structure
136 *
137 *	Registers a pair of callbacks function to be called upon addition
138 *	or removal of MTD devices. Causes the 'add' callback to be immediately
139 *	invoked for each MTD device currently present in the system.
140 */
141
142void register_mtd_user (struct mtd_notifier *new)
143{
144	int i;
145
146	mutex_lock(&mtd_table_mutex);
147
148	list_add(&new->list, &mtd_notifiers);
149
150 	__module_get(THIS_MODULE);
151
152	for (i=0; i< MAX_MTD_DEVICES; i++)
153		if (mtd_table[i])
154			new->add(mtd_table[i]);
155
156	mutex_unlock(&mtd_table_mutex);
157}
158
159/**
160 *	unregister_mtd_user - unregister a 'user' of MTD devices.
161 *	@old: pointer to notifier info structure
162 *
163 *	Removes a callback function pair from the list of 'users' to be
164 *	notified upon addition or removal of MTD devices. Causes the
165 *	'remove' callback to be immediately invoked for each MTD device
166 *	currently present in the system.
167 */
168
169int unregister_mtd_user (struct mtd_notifier *old)
170{
171	int i;
172
173	mutex_lock(&mtd_table_mutex);
174
175	module_put(THIS_MODULE);
176
177	for (i=0; i< MAX_MTD_DEVICES; i++)
178		if (mtd_table[i])
179			old->remove(mtd_table[i]);
180
181	list_del(&old->list);
182	mutex_unlock(&mtd_table_mutex);
183	return 0;
184}
185
186
187/**
188 *	get_mtd_device - obtain a validated handle for an MTD device
189 *	@mtd: last known address of the required MTD device
190 *	@num: internal device number of the required MTD device
191 *
192 *	Given a number and NULL address, return the num'th entry in the device
193 *	table, if any.	Given an address and num == -1, search the device table
194 *	for a device with that address and return if it's still present. Given
195 *	both, return the num'th driver only if its address matches. Return
196 *	error code if not.
197 */
198
199struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
200{
201	struct mtd_info *ret = NULL;
202	int i, err = -ENODEV;
203
204	mutex_lock(&mtd_table_mutex);
205
206	if (num == -1) {
207		for (i=0; i< MAX_MTD_DEVICES; i++)
208			if (mtd_table[i] == mtd)
209				ret = mtd_table[i];
210	} else if (num < MAX_MTD_DEVICES) {
211		ret = mtd_table[num];
212		if (mtd && mtd != ret)
213			ret = NULL;
214	}
215
216	if (!ret)
217		goto out_unlock;
218
219	if (!try_module_get(ret->owner))
220		goto out_unlock;
221
222	if (ret->get_device) {
223		err = ret->get_device(ret);
224		if (err)
225			goto out_put;
226	}
227
228	ret->usecount++;
229	mutex_unlock(&mtd_table_mutex);
230	return ret;
231
232out_put:
233	module_put(ret->owner);
234out_unlock:
235	mutex_unlock(&mtd_table_mutex);
236	return ERR_PTR(err);
237}
238
239/**
240 *	get_mtd_device_nm - obtain a validated handle for an MTD device by
241 *	device name
242 *	@name: MTD device name to open
243 *
244 * 	This function returns MTD device description structure in case of
245 * 	success and an error code in case of failure.
246 */
247
248struct mtd_info *get_mtd_device_nm(const char *name)
249{
250	int i, err = -ENODEV;
251	struct mtd_info *mtd = NULL;
252
253	mutex_lock(&mtd_table_mutex);
254
255	for (i = 0; i < MAX_MTD_DEVICES; i++) {
256		if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
257			mtd = mtd_table[i];
258			break;
259		}
260	}
261
262	if (!mtd)
263		goto out_unlock;
264
265	if (!try_module_get(mtd->owner))
266		goto out_unlock;
267
268	if (mtd->get_device) {
269		err = mtd->get_device(mtd);
270		if (err)
271			goto out_put;
272	}
273
274	mtd->usecount++;
275	mutex_unlock(&mtd_table_mutex);
276	return mtd;
277
278out_put:
279	module_put(mtd->owner);
280out_unlock:
281	mutex_unlock(&mtd_table_mutex);
282	return ERR_PTR(err);
283}
284
285void put_mtd_device(struct mtd_info *mtd)
286{
287	int c;
288
289	mutex_lock(&mtd_table_mutex);
290	c = --mtd->usecount;
291	if (mtd->put_device)
292		mtd->put_device(mtd);
293	mutex_unlock(&mtd_table_mutex);
294	BUG_ON(c < 0);
295
296	module_put(mtd->owner);
297}
298
299/* default_mtd_writev - default mtd writev method for MTD devices that
300 *			don't implement their own
301 */
302
303int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
304		       unsigned long count, loff_t to, size_t *retlen)
305{
306	unsigned long i;
307	size_t totlen = 0, thislen;
308	int ret = 0;
309
310	if(!mtd->write) {
311		ret = -EROFS;
312	} else {
313		for (i=0; i<count; i++) {
314			if (!vecs[i].iov_len)
315				continue;
316			ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
317			totlen += thislen;
318			if (ret || thislen != vecs[i].iov_len)
319				break;
320			to += vecs[i].iov_len;
321		}
322	}
323	if (retlen)
324		*retlen = totlen;
325	return ret;
326}
327
328EXPORT_SYMBOL_GPL(add_mtd_device);
329EXPORT_SYMBOL_GPL(del_mtd_device);
330EXPORT_SYMBOL_GPL(get_mtd_device);
331EXPORT_SYMBOL_GPL(get_mtd_device_nm);
332EXPORT_SYMBOL_GPL(put_mtd_device);
333EXPORT_SYMBOL_GPL(register_mtd_user);
334EXPORT_SYMBOL_GPL(unregister_mtd_user);
335EXPORT_SYMBOL_GPL(default_mtd_writev);
336
337#ifdef CONFIG_PROC_FS
338
339/*====================================================================*/
340/* Support for /proc/mtd */
341
342static struct proc_dir_entry *proc_mtd;
343
344static inline int mtd_proc_info (char *buf, int i)
345{
346	struct mtd_info *this = mtd_table[i];
347
348	if (!this)
349		return 0;
350
351	return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
352		       this->erasesize, this->name);
353}
354
355static int mtd_read_proc (char *page, char **start, off_t off, int count,
356			  int *eof, void *data_unused)
357{
358	int len, l, i;
359        off_t   begin = 0;
360
361	mutex_lock(&mtd_table_mutex);
362
363	len = sprintf(page, "dev:    size   erasesize  name\n");
364        for (i=0; i< MAX_MTD_DEVICES; i++) {
365
366                l = mtd_proc_info(page + len, i);
367                len += l;
368                if (len+begin > off+count)
369                        goto done;
370                if (len+begin < off) {
371                        begin += len;
372                        len = 0;
373                }
374        }
375
376        *eof = 1;
377
378done:
379	mutex_unlock(&mtd_table_mutex);
380        if (off >= len+begin)
381                return 0;
382        *start = page + (off-begin);
383        return ((count < begin+len-off) ? count : begin+len-off);
384}
385
386/*====================================================================*/
387/* Init code */
388
389static int __init init_mtd(void)
390{
391	if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
392		proc_mtd->read_proc = mtd_read_proc;
393	return 0;
394}
395
396static void __exit cleanup_mtd(void)
397{
398        if (proc_mtd)
399		remove_proc_entry( "mtd", NULL);
400}
401
402module_init(init_mtd);
403module_exit(cleanup_mtd);
404
405#endif /* CONFIG_PROC_FS */
406
407
408MODULE_LICENSE("GPL");
409MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
410MODULE_DESCRIPTION("Core MTD registration and access routines");
411