aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/plat-omap/mailbox.c
blob: 7a1f5c25fd17cff568e9c158dc2b96065d777b22 (plain) (blame)
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
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
/*
 * OMAP mailbox driver
 *
 * Copyright (C) 2006-2009 Nokia Corporation. All rights reserved.
 *
 * Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/delay.h>

#include <mach/mailbox.h>

static int enable_seq_bit;
module_param(enable_seq_bit, bool, 0);
MODULE_PARM_DESC(enable_seq_bit, "Enable sequence bit checking.");

static struct omap_mbox *mboxes;
static DEFINE_RWLOCK(mboxes_lock);

/*
 * Mailbox sequence bit API
 */

/* seq_rcv should be initialized with any value other than
 * 0 and 1 << 31, to allow either value for the first
 * message.  */
static inline void mbox_seq_init(struct omap_mbox *mbox)
{
	if (!enable_seq_bit)
		return;

	/* any value other than 0 and 1 << 31 */
	mbox->seq_rcv = 0xffffffff;
}

static inline void mbox_seq_toggle(struct omap_mbox *mbox, mbox_msg_t * msg)
{
	if (!enable_seq_bit)
		return;

	/* add seq_snd to msg */
	*msg = (*msg & 0x7fffffff) | mbox->seq_snd;
	/* flip seq_snd */
	mbox->seq_snd ^= 1 << 31;
}

static inline int mbox_seq_test(struct omap_mbox *mbox, mbox_msg_t msg)
{
	mbox_msg_t seq;

	if (!enable_seq_bit)
		return 0;

	seq = msg & (1 << 31);
	if (seq == mbox->seq_rcv)
		return -1;
	mbox->seq_rcv = seq;
	return 0;
}

/* Mailbox FIFO handle functions */
static inline mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
{
	return mbox->ops->fifo_read(mbox);
}
static inline void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
{
	mbox->ops->fifo_write(mbox, msg);
}
static inline int mbox_fifo_empty(struct omap_mbox *mbox)
{
	return mbox->ops->fifo_empty(mbox);
}
static inline int mbox_fifo_full(struct omap_mbox *mbox)
{
	return mbox->ops->fifo_full(mbox);
}

/* Mailbox IRQ handle functions */
static inline void enable_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
{
	mbox->ops->enable_irq(mbox, irq);
}
static inline void disable_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
{
	mbox->ops->disable_irq(mbox, irq);
}
static inline void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
{
	if (mbox->ops->ack_irq)
		mbox->ops->ack_irq(mbox, irq);
}
static inline int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
{
	return mbox->ops->is_irq(mbox, irq);
}

/* Mailbox Sequence Bit function */
void omap_mbox_init_seq(struct omap_mbox *mbox)
{
	mbox_seq_init(mbox);
}
EXPORT_SYMBOL(omap_mbox_init_seq);

/*
 * message sender
 */
static int __mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void *arg)
{
	int ret = 0, i = 1000;

	while (mbox_fifo_full(mbox)) {
		if (mbox->ops->type == OMAP_MBOX_TYPE2)
			return -1;
		if (--i == 0)
			return -1;
		udelay(1);
	}

	if (arg && mbox->txq->callback) {
		ret = mbox->txq->callback(arg);
		if (ret)
			goto out;
	}

	mbox_seq_toggle(mbox, &msg);
	mbox_fifo_write(mbox, msg);
 out:
	return ret;
}

struct omap_msg_tx_data {
	mbox_msg_t	msg;
	void		*arg;
};

static void omap_msg_tx_end_io(struct request *rq, int error)
{
	kfree(rq->special);
	__blk_put_request(rq->q, rq);
}

int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void* arg)
{
	struct omap_msg_tx_data *tx_data;
	struct request *rq;
	struct request_queue *q = mbox->txq->queue;

	tx_data = kmalloc(sizeof(*tx_data), GFP_ATOMIC);
	if (unlikely(!tx_data))
		return -ENOMEM;

	rq = blk_get_request(q, WRITE, GFP_ATOMIC);
	if (unlikely(!rq)) {
		kfree(tx_data);
		return -ENOMEM;
	}

	tx_data->msg = msg;
	tx_data->arg = arg;
	rq->end_io = omap_msg_tx_end_io;
	blk_insert_request(q, rq, 0, tx_data);

	schedule_work(&mbox->txq->work);
	return 0;
}
EXPORT_SYMBOL(omap_mbox_msg_send);

static void mbox_tx_work(struct work_struct *work)
{
	int ret;
	struct request *rq;
	struct omap_mbox_queue *mq = container_of(work,
				struct omap_mbox_queue, work);
	struct omap_mbox *mbox = mq->queue->queuedata;
	struct request_queue *q = mbox->txq->queue;

	while (1) {
		struct omap_msg_tx_data *tx_data;

		spin_lock(q->queue_lock);
		rq = elv_next_request(q);
		if (rq)
			blkdev_dequeue_request(rq);
		spin_unlock(q->queue_lock);

		if (!rq)
			break;

		tx_data = rq->special;

		ret = __mbox_msg_send(mbox, tx_data->msg, tx_data->arg);
		if (ret) {
			enable_mbox_irq(mbox, IRQ_TX);
			spin_lock(q->queue_lock);
			blk_requeue_request(q, rq);
			spin_unlock(q->queue_lock);
			return;
		}

		spin_lock(q->queue_lock);
		__blk_end_request_all(rq, 0);
		spin_unlock(q->queue_lock);
	}
}

/*
 * Message receiver(workqueue)
 */
static void mbox_rx_work(struct work_struct *work)
{
	struct omap_mbox_queue *mq =
			container_of(work, struct omap_mbox_queue, work);
	struct omap_mbox *mbox = mq->queue->queuedata;
	struct request_queue *q = mbox->rxq->queue;
	struct request *rq;
	mbox_msg_t msg;
	unsigned long flags;

	if (mbox->rxq->callback == NULL) {
		sysfs_notify(&mbox->dev->kobj, NULL, "mbox");
		return;
	}

	while (1) {
		spin_lock_irqsave(q->queue_lock, flags);
		rq = elv_next_request(q);
		if (rq)
			blkdev_dequeue_request(rq);
		spin_unlock_irqrestore(q->queue_lock, flags);
		if (!rq)
			break;

		msg = (mbox_msg_t)rq->special;
		blk_end_request_all(rq, 0);
		mbox->rxq->callback((void *)msg);
	}
}

/*
 * Mailbox interrupt handler
 */
static void mbox_txq_fn(struct request_queue * q)
{
}

static void mbox_rxq_fn(struct request_queue * q)
{
}

static void __mbox_tx_interrupt(struct omap_mbox *mbox)
{
	disable_mbox_irq(mbox, IRQ_TX);
	ack_mbox_irq(mbox, IRQ_TX);
	schedule_work(&mbox->txq->work);
}

static void __mbox_rx_interrupt(struct omap_mbox *mbox)
{
	struct request *rq;
	mbox_msg_t msg;
	struct request_queue *q = mbox->rxq->queue;

	disable_mbox_irq(mbox, IRQ_RX);

	while (!mbox_fifo_empty(mbox)) {
		rq = blk_get_request(q, WRITE, GFP_ATOMIC);
		if (unlikely(!rq))
			goto nomem;

		msg = mbox_fifo_read(mbox);

		if (unlikely(mbox_seq_test(mbox, msg))) {
			pr_info("mbox: Illegal seq bit!(%08x)\n", msg);
			if (mbox->err_notify)
				mbox->err_notify();
		}

		blk_insert_request(q, rq, 0, (void *)msg);
		if (mbox->ops->type == OMAP_MBOX_TYPE1)
			break;
	}

	/* no more messages in the fifo. clear IRQ source. */
	ack_mbox_irq(mbox, IRQ_RX);
	enable_mbox_irq(mbox, IRQ_RX);
nomem:
	schedule_work(&mbox->rxq->work);
}

static irqreturn_t mbox_interrupt(int irq, void *p)
{
	struct omap_mbox *mbox = p;

	if (is_mbox_irq(mbox, IRQ_TX))
		__mbox_tx_interrupt(mbox);

	if (is_mbox_irq(mbox, IRQ_RX))
		__mbox_rx_interrupt(mbox);

	return IRQ_HANDLED;
}

/*
 * sysfs files
 */
static ssize_t
omap_mbox_write(struct device *dev, struct device_attribute *attr,
		const char * buf, size_t count)
{
	int ret;
	mbox_msg_t *p = (mbox_msg_t *)buf;
	struct omap_mbox *mbox = dev_get_drvdata(dev);

	for (; count >= sizeof(mbox_msg_t); count -= sizeof(mbox_msg_t)) {
		ret = omap_mbox_msg_send(mbox, be32_to_cpu(*p), NULL);
		if (ret)
			return -EAGAIN;
		p++;
	}

	return (size_t)((char *)p - buf);
}

static ssize_t
omap_mbox_read(struct device *dev, struct device_attribute *attr, char *buf)
{
	unsigned long flags;
	struct request *rq;
	mbox_msg_t *p = (mbox_msg_t *) buf;
	struct omap_mbox *mbox = dev_get_drvdata(dev);
	struct request_queue *q = mbox->rxq->queue;

	while (1) {
		spin_lock_irqsave(q->queue_lock, flags);
		rq = elv_next_request(q);
		if (rq)
			blkdev_dequeue_request(rq);
		spin_unlock_irqrestore(q->queue_lock, flags);

		if (!rq)
			break;

		*p = (mbox_msg_t)rq->special;

		blk_end_request_all(rq, 0);

		if (unlikely(mbox_seq_test(mbox, *p))) {
			pr_info("mbox: Illegal seq bit!(%08x) ignored\n", *p);
			continue;
		}
		p++;
	}

	pr_debug("%02x %02x %02x %02x\n", buf[0], buf[1], buf[2], buf[3]);

	return (size_t) ((char *)p - buf);
}

static DEVICE_ATTR(mbox, S_IRUGO | S_IWUSR, omap_mbox_read, omap_mbox_write);

static ssize_t mbox_show(struct class *class, char *buf)
{
	return sprintf(buf, "mbox");
}

static CLASS_ATTR(mbox, S_IRUGO, mbox_show, NULL);

static struct class omap_mbox_class = {
	.name = "omap-mailbox",
};

static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
					request_fn_proc * proc,
					void (*work) (struct work_struct *))
{
	struct request_queue *q;
	struct omap_mbox_queue *mq;

	mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
	if (!mq)
		return NULL;

	spin_lock_init(&mq->lock);

	q = blk_init_queue(proc, &mq->lock);
	if (!q)
		goto error;
	q->queuedata = mbox;
	mq->queue = q;

	INIT_WORK(&mq->work, work);

	return mq;
error:
	kfree(mq);
	return NULL;
}

static void mbox_queue_free(struct omap_mbox_queue *q)
{
	blk_cleanup_queue(q->queue);
	kfree(q);
}

static int omap_mbox_init(struct omap_mbox *mbox)
{
	int ret;
	struct omap_mbox_queue *mq;

	if (likely(mbox->ops->startup)) {
		ret = mbox->ops->startup(mbox);
		if (unlikely(ret))
			return ret;
	}

	ret = request_irq(mbox->irq, mbox_interrupt, IRQF_DISABLED,
				mbox->name, mbox);
	if (unlikely(ret)) {
		printk(KERN_ERR
			"failed to register mailbox interrupt:%d\n", ret);
		goto fail_request_irq;
	}

	mq = mbox_queue_alloc(mbox, mbox_txq_fn, mbox_tx_work);
	if (!mq) {
		ret = -ENOMEM;
		goto fail_alloc_txq;
	}
	mbox->txq = mq;

	mq = mbox_queue_alloc(mbox, mbox_rxq_fn, mbox_rx_work);
	if (!mq) {
		ret = -ENOMEM;
		goto fail_alloc_rxq;
	}
	mbox->rxq = mq;

	return 0;

 fail_alloc_rxq:
	mbox_queue_free(mbox->txq);
 fail_alloc_txq:
	free_irq(mbox->irq, mbox);
 fail_request_irq:
	if (unlikely(mbox->ops->shutdown))
		mbox->ops->shutdown(mbox);

	return ret;
}

static void omap_mbox_fini(struct omap_mbox *mbox)
{
	mbox_queue_free(mbox->txq);
	mbox_queue_free(mbox->rxq);

	free_irq(mbox->irq, mbox);

	if (unlikely(mbox->ops->shutdown))
		mbox->ops->shutdown(mbox);
}

static struct omap_mbox **find_mboxes(const char *name)
{
	struct omap_mbox **p;

	for (p = &mboxes; *p; p = &(*p)->next) {
		if (strcmp((*p)->name, name) == 0)
			break;
	}

	return p;
}

struct omap_mbox *omap_mbox_get(const char *name)
{
	struct omap_mbox *mbox;
	int ret;

	read_lock(&mboxes_lock);
	mbox = *(find_mboxes(name));
	if (mbox == NULL) {
		read_unlock(&mboxes_lock);
		return ERR_PTR(-ENOENT);
	}

	read_unlock(&mboxes_lock);

	ret = omap_mbox_init(mbox);
	if (ret)
		return ERR_PTR(-ENODEV);

	return mbox;
}
EXPORT_SYMBOL(omap_mbox_get);

void omap_mbox_put(struct omap_mbox *mbox)
{
	omap_mbox_fini(mbox);
}
EXPORT_SYMBOL(omap_mbox_put);

int omap_mbox_register(struct device *parent, struct omap_mbox *mbox)
{
	int ret = 0;
	struct omap_mbox **tmp;

	if (!mbox)
		return -EINVAL;
	if (mbox->next)
		return -EBUSY;

	mbox->dev = device_create(&omap_mbox_class,
				  parent, 0, mbox, "%s", mbox->name);
	if (IS_ERR(mbox->dev))
		return PTR_ERR(mbox->dev);

	ret = device_create_file(mbox->dev, &dev_attr_mbox);
	if (ret)
		goto err_sysfs;

	write_lock(&mboxes_lock);
	tmp = find_mboxes(mbox->name);
	if (*tmp) {
		ret = -EBUSY;
		write_unlock(&mboxes_lock);
		goto err_find;
	}
	*tmp = mbox;
	write_unlock(&mboxes_lock);

	return 0;

err_find:
	device_remove_file(mbox->dev, &dev_attr_mbox);
err_sysfs:
	device_unregister(mbox->dev);
	return ret;
}
EXPORT_SYMBOL(omap_mbox_register);

int omap_mbox_unregister(struct omap_mbox *mbox)
{
	struct omap_mbox **tmp;

	write_lock(&mboxes_lock);
	tmp = &mboxes;
	while (*tmp) {
		if (mbox == *tmp) {
			*tmp = mbox->next;
			mbox->next = NULL;
			write_unlock(&mboxes_lock);
			device_remove_file(mbox->dev, &dev_attr_mbox);
			device_unregister(mbox->dev);
			return 0;
		}
		tmp = &(*tmp)->next;
	}
	write_unlock(&mboxes_lock);

	return -EINVAL;
}
EXPORT_SYMBOL(omap_mbox_unregister);

static int __init omap_mbox_class_init(void)
{
	int ret = class_register(&omap_mbox_class);
	if (!ret)
		ret = class_create_file(&omap_mbox_class, &class_attr_mbox);

	return ret;
}

static void __exit omap_mbox_class_exit(void)
{
	class_remove_file(&omap_mbox_class, &class_attr_mbox);
	class_unregister(&omap_mbox_class);
}

subsys_initcall(omap_mbox_class_init);
module_exit(omap_mbox_class_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
MODULE_AUTHOR("Toshihiro Kobayashi and Hiroshi DOYU");