summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/mtdcore.c
blob: 9c3813486a1a2878b0f8096b9855652a0ad336ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
/*
 * $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
 *
 * Core registration and callback routines for MTD
 * drivers and users.
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/mtd/compatmac.h>
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#endif

#include <linux/mtd/mtd.h>

/* These are exported solely for the purpose of mtd_blkdevs.c. You
   should not use them for _anything_ else */
DEFINE_MUTEX(mtd_table_mutex);
struct mtd_info *mtd_table[MAX_MTD_DEVICES];

EXPORT_SYMBOL_GPL(mtd_table_mutex);
EXPORT_SYMBOL_GPL(mtd_table);

static LIST_HEAD(mtd_notifiers);

/**
 *	add_mtd_device - register an MTD device
 *	@mtd: pointer to new MTD device info structure
 *
 *	Add a device to the list of MTD devices present in the system, and
 *	notify each currently active MTD 'user' of its arrival. Returns
 *	zero on success or 1 on failure, which currently will only happen
 *	if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
 */

int add_mtd_device(struct mtd_info *mtd)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	for (i=0; i < MAX_MTD_DEVICES; i++)
		if (!mtd_table[i]) {
			struct list_head *this;

			mtd_table[i] = mtd;
			mtd->index = i;
			mtd->usecount = 0;

			DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
			/* No need to get a refcount on the module containing
			   the notifier, since we hold the mtd_table_mutex */
			list_for_each(this, &mtd_notifiers) {
				struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
				not->add(mtd);
			}

			mutex_unlock(&mtd_table_mutex);
			/* We _know_ we aren't being removed, because
			   our caller is still holding us here. So none
			   of this try_ nonsense, and no bitching about it
			   either. :) */
			__module_get(THIS_MODULE);
			return 0;
		}

	mutex_unlock(&mtd_table_mutex);
	return 1;
}

/**
 *	del_mtd_device - unregister an MTD device
 *	@mtd: pointer to MTD device info structure
 *
 *	Remove a device from the list of MTD devices present in the system,
 *	and notify each currently active MTD 'user' of its departure.
 *	Returns zero on success or 1 on failure, which currently will happen
 *	if the requested device does not appear to be present in the list.
 */

int del_mtd_device (struct mtd_info *mtd)
{
	int ret;

	mutex_lock(&mtd_table_mutex);

	if (mtd_table[mtd->index] != mtd) {
		ret = -ENODEV;
	} else if (mtd->usecount) {
		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
		       mtd->index, mtd->name, mtd->usecount);
		ret = -EBUSY;
	} else {
		struct list_head *this;

		/* No need to get a refcount on the module containing
		   the notifier, since we hold the mtd_table_mutex */
		list_for_each(this, &mtd_notifiers) {
			struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
			not->remove(mtd);
		}

		mtd_table[mtd->index] = NULL;

		module_put(THIS_MODULE);
		ret = 0;
	}

	mutex_unlock(&mtd_table_mutex);
	return ret;
}

/**
 *	register_mtd_user - register a 'user' of MTD devices.
 *	@new: pointer to notifier info structure
 *
 *	Registers a pair of callbacks function to be called upon addition
 *	or removal of MTD devices. Causes the 'add' callback to be immediately
 *	invoked for each MTD device currently present in the system.
 */

void register_mtd_user (struct mtd_notifier *new)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	list_add(&new->list, &mtd_notifiers);

 	__module_get(THIS_MODULE);

	for (i=0; i< MAX_MTD_DEVICES; i++)
		if (mtd_table[i])
			new->add(mtd_table[i]);

	mutex_unlock(&mtd_table_mutex);
}

/**
 *	unregister_mtd_user - unregister a 'user' of MTD devices.
 *	@old: pointer to notifier info structure
 *
 *	Removes a callback function pair from the list of 'users' to be
 *	notified upon addition or removal of MTD devices. Causes the
 *	'remove' callback to be immediately invoked for each MTD device
 *	currently present in the system.
 */

int unregister_mtd_user (struct mtd_notifier *old)
{
	int i;

	mutex_lock(&mtd_table_mutex);

	module_put(THIS_MODULE);

	for (i=0; i< MAX_MTD_DEVICES; i++)
		if (mtd_table[i])
			old->remove(mtd_table[i]);

	list_del(&old->list);
	mutex_unlock(&mtd_table_mutex);
	return 0;
}


/**
 *	get_mtd_device - obtain a validated handle for an MTD device
 *	@mtd: last known address of the required MTD device
 *	@num: internal device number of the required MTD device
 *
 *	Given a number and NULL address, return the num'th entry in the device
 *	table, if any.	Given an address and num == -1, search the device table
 *	for a device with that address and return if it's still present. Given
 *	both, return the num'th driver only if its address matches. Return NULL
 *	if not.
 */

struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
	struct mtd_info *ret = NULL;
	int i;

	mutex_lock(&mtd_table_mutex);

	if (num == -1) {
		for (i=0; i< MAX_MTD_DEVICES; i++)
			if (mtd_table[i] == mtd)
				ret = mtd_table[i];
	} else if (num < MAX_MTD_DEVICES) {
		ret = mtd_table[num];
		if (mtd && mtd != ret)
			ret = NULL;
	}

	if (ret && !try_module_get(ret->owner))
		ret = NULL;

	if (ret)
		ret->usecount++;

	mutex_unlock(&mtd_table_mutex);
	return ret;
}

void put_mtd_device(struct mtd_info *mtd)
{
	int c;

	mutex_lock(&mtd_table_mutex);
	c = --mtd->usecount;
	mutex_unlock(&mtd_table_mutex);
	BUG_ON(c < 0);

	module_put(mtd->owner);
}

/* default_mtd_writev - default mtd writev method for MTD devices that
 *			dont implement their own
 */

int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
		       unsigned long count, loff_t to, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	if(!mtd->write) {
		ret = -EROFS;
	} else {
		for (i=0; i<count; i++) {
			if (!vecs[i].iov_len)
				continue;
			ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
			totlen += thislen;
			if (ret || thislen != vecs[i].iov_len)
				break;
			to += vecs[i].iov_len;
		}
	}
	if (retlen)
		*retlen = totlen;
	return ret;
}


/* default_mtd_readv - default mtd readv method for MTD devices that dont
 *		       implement their own
 */

int default_mtd_readv(struct mtd_info *mtd, struct kvec *vecs,
		      unsigned long count, loff_t from, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	if(!mtd->read) {
		ret = -EIO;
	} else {
		for (i=0; i<count; i++) {
			if (!vecs[i].iov_len)
				continue;
			ret = mtd->read(mtd, from, vecs[i].iov_len, &thislen, vecs[i].iov_base);
			totlen += thislen;
			if (ret || thislen != vecs[i].iov_len)
				break;
			from += vecs[i].iov_len;
		}
	}
	if (retlen)
		*retlen = totlen;
	return ret;
}


EXPORT_SYMBOL(add_mtd_device);
EXPORT_SYMBOL(del_mtd_device);
EXPORT_SYMBOL(get_mtd_device);
EXPORT_SYMBOL(put_mtd_device);
EXPORT_SYMBOL(register_mtd_user);
EXPORT_SYMBOL(unregister_mtd_user);
EXPORT_SYMBOL(default_mtd_writev);
EXPORT_SYMBOL(default_mtd_readv);

/*====================================================================*/
/* Support for /proc/mtd */

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_mtd;

static inline int mtd_proc_info (char *buf, int i)
{
	struct mtd_info *this = mtd_table[i];

	if (!this)
		return 0;

	return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
		       this->erasesize, this->name);
}

static int mtd_read_proc (char *page, char **start, off_t off, int count,
			  int *eof, void *data_unused)
{
	int len, l, i;
        off_t   begin = 0;

	mutex_lock(&mtd_table_mutex);

	len = sprintf(page, "dev:    size   erasesize  name\n");
        for (i=0; i< MAX_MTD_DEVICES; i++) {

                l = mtd_proc_info(page + len, i);
                len += l;
                if (len+begin > off+count)
                        goto done;
                if (len+begin < off) {
                        begin += len;
                        len = 0;
                }
        }

        *eof = 1;

done:
	mutex_unlock(&mtd_table_mutex);
        if (off >= len+begin)
                return 0;
        *start = page + (off-begin);
        return ((count < begin+len-off) ? count : begin+len-off);
}

#endif /* CONFIG_PROC_FS */

/*====================================================================*/
/* Init code */

static int __init init_mtd(void)
{
#ifdef CONFIG_PROC_FS
	if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
		proc_mtd->read_proc = mtd_read_proc;
#endif
	return 0;
}

static void __exit cleanup_mtd(void)
{
#ifdef CONFIG_PROC_FS
        if (proc_mtd)
		remove_proc_entry( "mtd", NULL);
#endif
}

module_init(init_mtd);
module_exit(cleanup_mtd);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Core MTD registration and access routines");