aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-ux500/mbox-db5500.c
blob: 2b2d51caf9d8b9f4db2e62c1eaa7a596b3313546 (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
/*
 * Copyright (C) ST-Ericsson SA 2010
 * Author: Stefan Nilsson <stefan.xk.nilsson@stericsson.com> for ST-Ericsson.
 * Author: Martin Persson <martin.persson@stericsson.com> for ST-Ericsson.
 * License terms: GNU General Public License (GPL), version 2.
 */

/*
 * Mailbox nomenclature:
 *
 *       APE           MODEM
 *           mbox pairX
 *   ..........................
 *   .                       .
 *   .           peer        .
 *   .     send  ----        .
 *   .      -->  |  |        .
 *   .           |  |        .
 *   .           ----        .
 *   .                       .
 *   .           local       .
 *   .     rec   ----        .
 *   .           |  | <--    .
 *   .           |  |        .
 *   .           ----        .
 *   .........................
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/platform_device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/completion.h>
#include <mach/mbox-db5500.h>

#define MBOX_NAME "mbox"

#define MBOX_FIFO_DATA        0x000
#define MBOX_FIFO_ADD         0x004
#define MBOX_FIFO_REMOVE      0x008
#define MBOX_FIFO_THRES_FREE  0x00C
#define MBOX_FIFO_THRES_OCCUP 0x010
#define MBOX_FIFO_STATUS      0x014

#define MBOX_DISABLE_IRQ 0x4
#define MBOX_ENABLE_IRQ  0x0
#define MBOX_LATCH 1

/* Global list of all mailboxes */
static struct list_head mboxs = LIST_HEAD_INIT(mboxs);

static struct mbox *get_mbox_with_id(u8 id)
{
	u8 i;
	struct list_head *pos = &mboxs;
	for (i = 0; i <= id; i++)
		pos = pos->next;

	return (struct mbox *) list_entry(pos, struct mbox, list);
}

int mbox_send(struct mbox *mbox, u32 mbox_msg, bool block)
{
	int res = 0;

	spin_lock(&mbox->lock);

	dev_dbg(&(mbox->pdev->dev),
		"About to buffer 0x%X to mailbox 0x%X."
		" ri = %d, wi = %d\n",
		mbox_msg, (u32)mbox, mbox->read_index,
		mbox->write_index);

	/* Check if write buffer is full */
	while (((mbox->write_index + 1) % MBOX_BUF_SIZE) == mbox->read_index) {
		if (!block) {
			dev_dbg(&(mbox->pdev->dev),
			"Buffer full in non-blocking call! "
			"Returning -ENOMEM!\n");
			res = -ENOMEM;
			goto exit;
		}
		spin_unlock(&mbox->lock);
		dev_dbg(&(mbox->pdev->dev),
			"Buffer full in blocking call! Sleeping...\n");
		mbox->client_blocked = 1;
		wait_for_completion(&mbox->buffer_available);
		dev_dbg(&(mbox->pdev->dev),
			"Blocking send was woken up! Trying again...\n");
		spin_lock(&mbox->lock);
	}

	mbox->buffer[mbox->write_index] = mbox_msg;
	mbox->write_index = (mbox->write_index + 1) % MBOX_BUF_SIZE;

	/*
	 * Indicate that we want an IRQ as soon as there is a slot
	 * in the FIFO
	 */
	writel(MBOX_ENABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);

exit:
	spin_unlock(&mbox->lock);
	return res;
}
EXPORT_SYMBOL(mbox_send);

#if defined(CONFIG_DEBUG_FS)
/*
 * Expected input: <value> <nbr sends>
 * Example: "echo 0xdeadbeef 4 > mbox-node" sends 0xdeadbeef 4 times
 */
static ssize_t mbox_write_fifo(struct device *dev,
			       struct device_attribute *attr,
			       const char *buf,
			       size_t count)
{
	unsigned long mbox_mess;
	unsigned long nbr_sends;
	unsigned long i;
	char int_buf[16];
	char *token;
	char *val;

	struct mbox *mbox = (struct mbox *) dev->platform_data;

	strncpy((char *) &int_buf, buf, sizeof(int_buf));
	token = (char *) &int_buf;

	/* Parse message */
	val = strsep(&token, " ");
	if ((val == NULL) || (strict_strtoul(val, 16, &mbox_mess) != 0))
		mbox_mess = 0xDEADBEEF;

	val = strsep(&token, " ");
	if ((val == NULL) || (strict_strtoul(val, 10, &nbr_sends) != 0))
		nbr_sends = 1;

	dev_dbg(dev, "Will write 0x%lX %ld times using data struct at 0x%X\n",
		mbox_mess, nbr_sends, (u32) mbox);

	for (i = 0; i < nbr_sends; i++)
		mbox_send(mbox, mbox_mess, true);

	return count;
}

static ssize_t mbox_read_fifo(struct device *dev,
			      struct device_attribute *attr,
			      char *buf)
{
	int mbox_value;
	struct mbox *mbox = (struct mbox *) dev->platform_data;

	if ((readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7) <= 0)
		return sprintf(buf, "Mailbox is empty\n");

	mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
	writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));

	return sprintf(buf, "0x%X\n", mbox_value);
}

static DEVICE_ATTR(fifo, S_IWUGO | S_IRUGO, mbox_read_fifo, mbox_write_fifo);

static int mbox_show(struct seq_file *s, void *data)
{
	struct list_head *pos;
	u8 mbox_index = 0;

	list_for_each(pos, &mboxs) {
		struct mbox *m =
			(struct mbox *) list_entry(pos, struct mbox, list);
		if (m == NULL) {
			seq_printf(s,
				   "Unable to retrieve mailbox %d\n",
				   mbox_index);
			continue;
		}

		spin_lock(&m->lock);
		if ((m->virtbase_peer == NULL) || (m->virtbase_local == NULL)) {
			seq_printf(s, "MAILBOX %d not setup or corrupt\n",
				   mbox_index);
			spin_unlock(&m->lock);
			continue;
		}

		seq_printf(s,
		"===========================\n"
		" MAILBOX %d\n"
		" PEER MAILBOX DUMP\n"
		"---------------------------\n"
		"FIFO:                 0x%X (%d)\n"
		"Free     Threshold:   0x%.2X (%d)\n"
		"Occupied Threshold:   0x%.2X (%d)\n"
		"Status:               0x%.2X (%d)\n"
		"   Free spaces  (ot):    %d (%d)\n"
		"   Occup spaces (ot):    %d (%d)\n"
		"===========================\n"
		" LOCAL MAILBOX DUMP\n"
		"---------------------------\n"
		"FIFO:                 0x%.X (%d)\n"
		"Free     Threshold:   0x%.2X (%d)\n"
		"Occupied Threshold:   0x%.2X (%d)\n"
		"Status:               0x%.2X (%d)\n"
		"   Free spaces  (ot):    %d (%d)\n"
		"   Occup spaces (ot):    %d (%d)\n"
		"===========================\n"
		"write_index: %d\n"
		"read_index : %d\n"
		"===========================\n"
		"\n",
		mbox_index,
		readl(m->virtbase_peer + MBOX_FIFO_DATA),
		readl(m->virtbase_peer + MBOX_FIFO_DATA),
		readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
		readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
		readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
		readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
		readl(m->virtbase_peer + MBOX_FIFO_STATUS),
		readl(m->virtbase_peer + MBOX_FIFO_STATUS),
		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 4) & 0x7,
		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 7) & 0x1,
		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 0) & 0x7,
		(readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 3) & 0x1,
		readl(m->virtbase_local + MBOX_FIFO_DATA),
		readl(m->virtbase_local + MBOX_FIFO_DATA),
		readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
		readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
		readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
		readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
		readl(m->virtbase_local + MBOX_FIFO_STATUS),
		readl(m->virtbase_local + MBOX_FIFO_STATUS),
		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 4) & 0x7,
		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 7) & 0x1,
		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 0) & 0x7,
		(readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 3) & 0x1,
		m->write_index, m->read_index);
		mbox_index++;
		spin_unlock(&m->lock);
	}

	return 0;
}

static int mbox_open(struct inode *inode, struct file *file)
{
	return single_open(file, mbox_show, NULL);
}

static const struct file_operations mbox_operations = {
	.owner = THIS_MODULE,
	.open = mbox_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};
#endif

static irqreturn_t mbox_irq(int irq, void *arg)
{
	u32 mbox_value;
	int nbr_occup;
	int nbr_free;
	struct mbox *mbox = (struct mbox *) arg;

	spin_lock(&mbox->lock);

	dev_dbg(&(mbox->pdev->dev),
		"mbox IRQ [%d] received. ri = %d, wi = %d\n",
		irq, mbox->read_index, mbox->write_index);

	/*
	 * Check if we have any outgoing messages, and if there is space for
	 * them in the FIFO.
	 */
	if (mbox->read_index != mbox->write_index) {
		/*
		 * Check by reading FREE for LOCAL since that indicates
		 * OCCUP for PEER
		 */
		nbr_free = (readl(mbox->virtbase_local + MBOX_FIFO_STATUS)
			    >> 4) & 0x7;
		dev_dbg(&(mbox->pdev->dev),
			"Status indicates %d empty spaces in the FIFO!\n",
			nbr_free);

		while ((nbr_free > 0) &&
		       (mbox->read_index != mbox->write_index)) {
			/* Write the message and latch it into the FIFO */
			writel(mbox->buffer[mbox->read_index],
			       (mbox->virtbase_peer + MBOX_FIFO_DATA));
			writel(MBOX_LATCH,
			       (mbox->virtbase_peer + MBOX_FIFO_ADD));
			dev_dbg(&(mbox->pdev->dev),
				"Wrote message 0x%X to addr 0x%X\n",
				mbox->buffer[mbox->read_index],
				(u32) (mbox->virtbase_peer + MBOX_FIFO_DATA));

			nbr_free--;
			mbox->read_index =
				(mbox->read_index + 1) % MBOX_BUF_SIZE;
		}

		/*
		 * Check if we still want IRQ:s when there is free
		 * space to send
		 */
		if (mbox->read_index != mbox->write_index) {
			dev_dbg(&(mbox->pdev->dev),
				"Still have messages to send, but FIFO full. "
				"Request IRQ again!\n");
			writel(MBOX_ENABLE_IRQ,
			       mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
		} else {
			dev_dbg(&(mbox->pdev->dev),
				"No more messages to send. "
				"Do not request IRQ again!\n");
			writel(MBOX_DISABLE_IRQ,
			       mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
		}

		/*
		 * Check if we can signal any blocked clients that it is OK to
		 * start buffering again
		 */
		if (mbox->client_blocked &&
		    (((mbox->write_index + 1) % MBOX_BUF_SIZE)
		     != mbox->read_index)) {
			dev_dbg(&(mbox->pdev->dev),
				"Waking up blocked client\n");
			complete(&mbox->buffer_available);
			mbox->client_blocked = 0;
		}
	}

	/* Check if we have any incoming messages */
	nbr_occup = readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7;
	if (nbr_occup == 0)
		goto exit;

	if (mbox->cb == NULL) {
		dev_dbg(&(mbox->pdev->dev), "No receive callback registered, "
			"leaving %d incoming messages in fifo!\n", nbr_occup);
		goto exit;
	}

	/* Read and acknowledge the message */
	mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
	writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));

	/* Notify consumer of new mailbox message */
	dev_dbg(&(mbox->pdev->dev), "Calling callback for message 0x%X!\n",
		mbox_value);
	mbox->cb(mbox_value, mbox->client_data);

exit:
	dev_dbg(&(mbox->pdev->dev), "Exit mbox IRQ. ri = %d, wi = %d\n",
		mbox->read_index, mbox->write_index);
	spin_unlock(&mbox->lock);

	return IRQ_HANDLED;
}

/* Setup is executed once for each mbox pair */
struct mbox *mbox_setup(u8 mbox_id, mbox_recv_cb_t *mbox_cb, void *priv)
{
	struct resource *resource;
	int irq;
	int res;
	struct mbox *mbox;

	mbox = get_mbox_with_id(mbox_id);
	if (mbox == NULL) {
		dev_err(&(mbox->pdev->dev), "Incorrect mailbox id: %d!\n",
			mbox_id);
		goto exit;
	}

	/*
	 * Check if mailbox has been allocated to someone else,
	 * otherwise allocate it
	 */
	if (mbox->allocated) {
		dev_err(&(mbox->pdev->dev), "Mailbox number %d is busy!\n",
			mbox_id);
		mbox = NULL;
		goto exit;
	}
	mbox->allocated = true;

	dev_dbg(&(mbox->pdev->dev), "Initiating mailbox number %d: 0x%X...\n",
		mbox_id, (u32)mbox);

	mbox->client_data = priv;
	mbox->cb = mbox_cb;

	/* Get addr for peer mailbox and ioremap it */
	resource = platform_get_resource_byname(mbox->pdev,
						IORESOURCE_MEM,
						"mbox_peer");
	if (resource == NULL) {
		dev_err(&(mbox->pdev->dev),
			"Unable to retrieve mbox peer resource\n");
		mbox = NULL;
		goto exit;
	}
	dev_dbg(&(mbox->pdev->dev),
		"Resource name: %s start: 0x%X, end: 0x%X\n",
		resource->name, resource->start, resource->end);
	mbox->virtbase_peer = ioremap(resource->start, resource_size(resource));
	if (!mbox->virtbase_peer) {
		dev_err(&(mbox->pdev->dev), "Unable to ioremap peer mbox\n");
		mbox = NULL;
		goto exit;
	}
	dev_dbg(&(mbox->pdev->dev),
		"ioremapped peer physical: (0x%X-0x%X) to virtual: 0x%X\n",
		resource->start, resource->end, (u32) mbox->virtbase_peer);

	/* Get addr for local mailbox and ioremap it */
	resource = platform_get_resource_byname(mbox->pdev,
						IORESOURCE_MEM,
						"mbox_local");
	if (resource == NULL) {
		dev_err(&(mbox->pdev->dev),
			"Unable to retrieve mbox local resource\n");
		mbox = NULL;
		goto exit;
	}
	dev_dbg(&(mbox->pdev->dev),
		"Resource name: %s start: 0x%X, end: 0x%X\n",
		resource->name, resource->start, resource->end);
	mbox->virtbase_local = ioremap(resource->start, resource_size(resource));
	if (!mbox->virtbase_local) {
		dev_err(&(mbox->pdev->dev), "Unable to ioremap local mbox\n");
		mbox = NULL;
		goto exit;
	}
	dev_dbg(&(mbox->pdev->dev),
		"ioremapped local physical: (0x%X-0x%X) to virtual: 0x%X\n",
		resource->start, resource->end, (u32) mbox->virtbase_peer);

	init_completion(&mbox->buffer_available);
	mbox->client_blocked = 0;

	/* Get IRQ for mailbox and allocate it */
	irq = platform_get_irq_byname(mbox->pdev, "mbox_irq");
	if (irq < 0) {
		dev_err(&(mbox->pdev->dev),
			"Unable to retrieve mbox irq resource\n");
		mbox = NULL;
		goto exit;
	}

	dev_dbg(&(mbox->pdev->dev), "Allocating irq %d...\n", irq);
	res = request_irq(irq, mbox_irq, 0, mbox->name, (void *) mbox);
	if (res < 0) {
		dev_err(&(mbox->pdev->dev),
			"Unable to allocate mbox irq %d\n", irq);
		mbox = NULL;
		goto exit;
	}

	/* Set up mailbox to not launch IRQ on free space in mailbox */
	writel(MBOX_DISABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);

	/*
	 * Set up mailbox to launch IRQ on new message if we have
	 * a callback set. If not, do not raise IRQ, but keep message
	 * in FIFO for manual retrieval
	 */
	if (mbox_cb != NULL)
		writel(MBOX_ENABLE_IRQ,
		       mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);
	else
		writel(MBOX_DISABLE_IRQ,
		       mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);

#if defined(CONFIG_DEBUG_FS)
	res = device_create_file(&(mbox->pdev->dev), &dev_attr_fifo);
	if (res != 0)
		dev_warn(&(mbox->pdev->dev),
			 "Unable to create mbox sysfs entry");

	(void) debugfs_create_file("mbox", S_IFREG | S_IRUGO, NULL,
				   NULL, &mbox_operations);
#endif

	dev_info(&(mbox->pdev->dev),
		 "Mailbox driver with index %d initiated!\n", mbox_id);

exit:
	return mbox;
}
EXPORT_SYMBOL(mbox_setup);


int __init mbox_probe(struct platform_device *pdev)
{
	struct mbox local_mbox;
	struct mbox *mbox;
	int res = 0;
	dev_dbg(&(pdev->dev), "Probing mailbox (pdev = 0x%X)...\n", (u32) pdev);

	memset(&local_mbox, 0x0, sizeof(struct mbox));

	/* Associate our mbox data with the platform device */
	res = platform_device_add_data(pdev,
				       (void *) &local_mbox,
				       sizeof(struct mbox));
	if (res != 0) {
		dev_err(&(pdev->dev),
			"Unable to allocate driver platform data!\n");
		goto exit;
	}

	mbox = (struct mbox *) pdev->dev.platform_data;
	mbox->pdev = pdev;
	mbox->write_index = 0;
	mbox->read_index = 0;

	INIT_LIST_HEAD(&(mbox->list));
	list_add_tail(&(mbox->list), &mboxs);

	sprintf(mbox->name, "%s", MBOX_NAME);
	spin_lock_init(&mbox->lock);

	dev_info(&(pdev->dev), "Mailbox driver loaded\n");

exit:
	return res;
}

static struct platform_driver mbox_driver = {
	.driver = {
		.name = MBOX_NAME,
		.owner = THIS_MODULE,
	},
};

static int __init mbox_init(void)
{
	return platform_driver_probe(&mbox_driver, mbox_probe);
}

module_init(mbox_init);

void __exit mbox_exit(void)
{
	platform_driver_unregister(&mbox_driver);
}

module_exit(mbox_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MBOX driver");