aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/etm.c
blob: 1bec8b5f22f05446df1c8fc60b6a9391df48b2dd (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
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
/*
 * linux/arch/arm/kernel/etm.c
 *
 * Driver for ARM's Embedded Trace Macrocell and Embedded Trace Buffer.
 *
 * Copyright (C) 2009 Nokia Corporation.
 * Alexander Shishkin
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/amba/bus.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <asm/hardware/coresight.h>
#include <asm/sections.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shishkin");

/*
 * ETM tracer state
 */
struct tracectx {
	unsigned int	etb_bufsz;
	void __iomem	*etb_regs;
	void __iomem	*etm_regs;
	unsigned long	flags;
	int		ncmppairs;
	int		etm_portsz;
	struct device	*dev;
	struct clk	*emu_clk;
	struct mutex	mutex;
};

static struct tracectx tracer;

static inline bool trace_isrunning(struct tracectx *t)
{
	return !!(t->flags & TRACER_RUNNING);
}

static int etm_setup_address_range(struct tracectx *t, int n,
		unsigned long start, unsigned long end, int exclude, int data)
{
	u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
		    ETMAAT_NOVALCMP;

	if (n < 1 || n > t->ncmppairs)
		return -EINVAL;

	/* comparators and ranges are numbered starting with 1 as opposed
	 * to bits in a word */
	n--;

	if (data)
		flags |= ETMAAT_DLOADSTORE;
	else
		flags |= ETMAAT_IEXEC;

	/* first comparator for the range */
	etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2));
	etm_writel(t, start, ETMR_COMP_VAL(n * 2));

	/* second comparator is right next to it */
	etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1));
	etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1));

	flags = exclude ? ETMTE_INCLEXCL : 0;
	etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);

	return 0;
}

static int trace_start(struct tracectx *t)
{
	u32 v;
	unsigned long timeout = TRACER_TIMEOUT;

	etb_unlock(t);

	etb_writel(t, 0, ETBR_FORMATTERCTRL);
	etb_writel(t, 1, ETBR_CTRL);

	etb_lock(t);

	/* configure etm */
	v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);

	if (t->flags & TRACER_CYCLE_ACC)
		v |= ETMCTRL_CYCLEACCURATE;

	etm_unlock(t);

	etm_writel(t, v, ETMR_CTRL);

	while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
		;
	if (!timeout) {
		dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
		etm_lock(t);
		return -EFAULT;
	}

	etm_setup_address_range(t, 1, (unsigned long)_stext,
			(unsigned long)_etext, 0, 0);
	etm_writel(t, 0, ETMR_TRACEENCTRL2);
	etm_writel(t, 0, ETMR_TRACESSCTRL);
	etm_writel(t, 0x6f, ETMR_TRACEENEVT);

	v &= ~ETMCTRL_PROGRAM;
	v |= ETMCTRL_PORTSEL;

	etm_writel(t, v, ETMR_CTRL);

	timeout = TRACER_TIMEOUT;
	while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
		;
	if (!timeout) {
		dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
		etm_lock(t);
		return -EFAULT;
	}

	etm_lock(t);

	t->flags |= TRACER_RUNNING;

	return 0;
}

static int trace_stop(struct tracectx *t)
{
	unsigned long timeout = TRACER_TIMEOUT;

	etm_unlock(t);

	etm_writel(t, 0x440, ETMR_CTRL);
	while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
		;
	if (!timeout) {
		dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
		etm_lock(t);
		return -EFAULT;
	}

	etm_lock(t);

	etb_unlock(t);
	etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);

	timeout = TRACER_TIMEOUT;
	while (etb_readl(t, ETBR_FORMATTERCTRL) &
			ETBFF_MANUAL_FLUSH && --timeout)
		;
	if (!timeout) {
		dev_dbg(t->dev, "Waiting for formatter flush to commence "
				"timed out\n");
		etb_lock(t);
		return -EFAULT;
	}

	etb_writel(t, 0, ETBR_CTRL);

	etb_lock(t);

	t->flags &= ~TRACER_RUNNING;

	return 0;
}

static int etb_getdatalen(struct tracectx *t)
{
	u32 v;
	int rp, wp;

	v = etb_readl(t, ETBR_STATUS);

	if (v & 1)
		return t->etb_bufsz;

	rp = etb_readl(t, ETBR_READADDR);
	wp = etb_readl(t, ETBR_WRITEADDR);

	if (rp > wp) {
		etb_writel(t, 0, ETBR_READADDR);
		etb_writel(t, 0, ETBR_WRITEADDR);

		return 0;
	}

	return wp - rp;
}

/* sysrq+v will always stop the running trace and leave it at that */
static void etm_dump(void)
{
	struct tracectx *t = &tracer;
	u32 first = 0;
	int length;

	if (!t->etb_regs) {
		printk(KERN_INFO "No tracing hardware found\n");
		return;
	}

	if (trace_isrunning(t))
		trace_stop(t);

	etb_unlock(t);

	length = etb_getdatalen(t);

	if (length == t->etb_bufsz)
		first = etb_readl(t, ETBR_WRITEADDR);

	etb_writel(t, first, ETBR_READADDR);

	printk(KERN_INFO "Trace buffer contents length: %d\n", length);
	printk(KERN_INFO "--- ETB buffer begin ---\n");
	for (; length; length--)
		printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM)));
	printk(KERN_INFO "\n--- ETB buffer end ---\n");

	/* deassert the overflow bit */
	etb_writel(t, 1, ETBR_CTRL);
	etb_writel(t, 0, ETBR_CTRL);

	etb_writel(t, 0, ETBR_TRIGGERCOUNT);
	etb_writel(t, 0, ETBR_READADDR);
	etb_writel(t, 0, ETBR_WRITEADDR);

	etb_lock(t);
}

static void sysrq_etm_dump(int key)
{
	dev_dbg(tracer.dev, "Dumping ETB buffer\n");
	etm_dump();
}

static struct sysrq_key_op sysrq_etm_op = {
	.handler = sysrq_etm_dump,
	.help_msg = "ETM buffer dump",
	.action_msg = "etm",
};

static int etb_open(struct inode *inode, struct file *file)
{
	if (!tracer.etb_regs)
		return -ENODEV;

	file->private_data = &tracer;

	return nonseekable_open(inode, file);
}

static ssize_t etb_read(struct file *file, char __user *data,
		size_t len, loff_t *ppos)
{
	int total, i;
	long length;
	struct tracectx *t = file->private_data;
	u32 first = 0;
	u32 *buf;

	mutex_lock(&t->mutex);

	if (trace_isrunning(t)) {
		length = 0;
		goto out;
	}

	etb_unlock(t);

	total = etb_getdatalen(t);
	if (total == t->etb_bufsz)
		first = etb_readl(t, ETBR_WRITEADDR);

	etb_writel(t, first, ETBR_READADDR);

	length = min(total * 4, (int)len);
	buf = vmalloc(length);

	dev_dbg(t->dev, "ETB buffer length: %d\n", total);
	dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
	for (i = 0; i < length / 4; i++)
		buf[i] = etb_readl(t, ETBR_READMEM);

	/* the only way to deassert overflow bit in ETB status is this */
	etb_writel(t, 1, ETBR_CTRL);
	etb_writel(t, 0, ETBR_CTRL);

	etb_writel(t, 0, ETBR_WRITEADDR);
	etb_writel(t, 0, ETBR_READADDR);
	etb_writel(t, 0, ETBR_TRIGGERCOUNT);

	etb_lock(t);

	length -= copy_to_user(data, buf, length);
	vfree(buf);

out:
	mutex_unlock(&t->mutex);

	return length;
}

static int etb_release(struct inode *inode, struct file *file)
{
	/* there's nothing to do here, actually */
	return 0;
}

static const struct file_operations etb_fops = {
	.owner = THIS_MODULE,
	.read = etb_read,
	.open = etb_open,
	.release = etb_release,
	.llseek = no_llseek,
};

static struct miscdevice etb_miscdev = {
	.name = "tracebuf",
	.minor = 0,
	.fops = &etb_fops,
};

static int __devinit etb_probe(struct amba_device *dev, const struct amba_id *id)
{
	struct tracectx *t = &tracer;
	int ret = 0;

	ret = amba_request_regions(dev, NULL);
	if (ret)
		goto out;

	t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
	if (!t->etb_regs) {
		ret = -ENOMEM;
		goto out_release;
	}

	amba_set_drvdata(dev, t);

	etb_miscdev.parent = &dev->dev;

	ret = misc_register(&etb_miscdev);
	if (ret)
		goto out_unmap;

	t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
	if (IS_ERR(t->emu_clk)) {
		dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
		return -EFAULT;
	}

	clk_enable(t->emu_clk);

	etb_unlock(t);
	t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
	dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);

	/* make sure trace capture is disabled */
	etb_writel(t, 0, ETBR_CTRL);
	etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
	etb_lock(t);

	dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");

out:
	return ret;

out_unmap:
	amba_set_drvdata(dev, NULL);
	iounmap(t->etb_regs);

out_release:
	amba_release_regions(dev);

	return ret;
}

static int etb_remove(struct amba_device *dev)
{
	struct tracectx *t = amba_get_drvdata(dev);

	amba_set_drvdata(dev, NULL);

	iounmap(t->etb_regs);
	t->etb_regs = NULL;

	clk_disable(t->emu_clk);
	clk_put(t->emu_clk);

	amba_release_regions(dev);

	return 0;
}

static struct amba_id etb_ids[] = {
	{
		.id	= 0x0003b907,
		.mask	= 0x0007ffff,
	},
	{ 0, 0 },
};

static struct amba_driver etb_driver = {
	.drv		= {
		.name	= "etb",
		.owner	= THIS_MODULE,
	},
	.probe		= etb_probe,
	.remove		= etb_remove,
	.id_table	= etb_ids,
};

/* use a sysfs file "trace_running" to start/stop tracing */
static ssize_t trace_running_show(struct kobject *kobj,
				  struct kobj_attribute *attr,
				  char *buf)
{
	return sprintf(buf, "%x\n", trace_isrunning(&tracer));
}

static ssize_t trace_running_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t n)
{
	unsigned int value;
	int ret;

	if (sscanf(buf, "%u", &value) != 1)
		return -EINVAL;

	mutex_lock(&tracer.mutex);
	ret = value ? trace_start(&tracer) : trace_stop(&tracer);
	mutex_unlock(&tracer.mutex);

	return ret ? : n;
}

static struct kobj_attribute trace_running_attr =
	__ATTR(trace_running, 0644, trace_running_show, trace_running_store);

static ssize_t trace_info_show(struct kobject *kobj,
				  struct kobj_attribute *attr,
				  char *buf)
{
	u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
	int datalen;

	etb_unlock(&tracer);
	datalen = etb_getdatalen(&tracer);
	etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
	etb_ra = etb_readl(&tracer, ETBR_READADDR);
	etb_st = etb_readl(&tracer, ETBR_STATUS);
	etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
	etb_lock(&tracer);

	etm_unlock(&tracer);
	etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
	etm_st = etm_readl(&tracer, ETMR_STATUS);
	etm_lock(&tracer);

	return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
			"ETBR_WRITEADDR:\t%08x\n"
			"ETBR_READADDR:\t%08x\n"
			"ETBR_STATUS:\t%08x\n"
			"ETBR_FORMATTERCTRL:\t%08x\n"
			"ETMR_CTRL:\t%08x\n"
			"ETMR_STATUS:\t%08x\n",
			datalen,
			tracer.ncmppairs,
			etb_wa,
			etb_ra,
			etb_st,
			etb_fc,
			etm_ctrl,
			etm_st
			);
}

static struct kobj_attribute trace_info_attr =
	__ATTR(trace_info, 0444, trace_info_show, NULL);

static ssize_t trace_mode_show(struct kobject *kobj,
				  struct kobj_attribute *attr,
				  char *buf)
{
	return sprintf(buf, "%d %d\n",
			!!(tracer.flags & TRACER_CYCLE_ACC),
			tracer.etm_portsz);
}

static ssize_t trace_mode_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t n)
{
	unsigned int cycacc, portsz;

	if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
		return -EINVAL;

	mutex_lock(&tracer.mutex);
	if (cycacc)
		tracer.flags |= TRACER_CYCLE_ACC;
	else
		tracer.flags &= ~TRACER_CYCLE_ACC;

	tracer.etm_portsz = portsz & 0x0f;
	mutex_unlock(&tracer.mutex);

	return n;
}

static struct kobj_attribute trace_mode_attr =
	__ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);

static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id)
{
	struct tracectx *t = &tracer;
	int ret = 0;

	if (t->etm_regs) {
		dev_dbg(&dev->dev, "ETM already initialized\n");
		ret = -EBUSY;
		goto out;
	}

	ret = amba_request_regions(dev, NULL);
	if (ret)
		goto out;

	t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
	if (!t->etm_regs) {
		ret = -ENOMEM;
		goto out_release;
	}

	amba_set_drvdata(dev, t);

	mutex_init(&t->mutex);
	t->dev = &dev->dev;
	t->flags = TRACER_CYCLE_ACC;
	t->etm_portsz = 1;

	etm_unlock(t);
	(void)etm_readl(t, ETMMR_PDSR);
	/* dummy first read */
	(void)etm_readl(&tracer, ETMMR_OSSRR);

	t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
	etm_writel(t, 0x440, ETMR_CTRL);
	etm_lock(t);

	ret = sysfs_create_file(&dev->dev.kobj,
			&trace_running_attr.attr);
	if (ret)
		goto out_unmap;

	/* failing to create any of these two is not fatal */
	ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
	if (ret)
		dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");

	ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
	if (ret)
		dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");

	dev_dbg(t->dev, "ETM AMBA driver initialized.\n");

out:
	return ret;

out_unmap:
	amba_set_drvdata(dev, NULL);
	iounmap(t->etm_regs);

out_release:
	amba_release_regions(dev);

	return ret;
}

static int etm_remove(struct amba_device *dev)
{
	struct tracectx *t = amba_get_drvdata(dev);

	amba_set_drvdata(dev, NULL);

	iounmap(t->etm_regs);
	t->etm_regs = NULL;

	amba_release_regions(dev);

	sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
	sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
	sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);

	return 0;
}

static struct amba_id etm_ids[] = {
	{
		.id	= 0x0003b921,
		.mask	= 0x0007ffff,
	},
	{ 0, 0 },
};

static struct amba_driver etm_driver = {
	.drv		= {
		.name   = "etm",
		.owner  = THIS_MODULE,
	},
	.probe		= etm_probe,
	.remove		= etm_remove,
	.id_table	= etm_ids,
};

static int __init etm_init(void)
{
	int retval;

	retval = amba_driver_register(&etb_driver);
	if (retval) {
		printk(KERN_ERR "Failed to register etb\n");
		return retval;
	}

	retval = amba_driver_register(&etm_driver);
	if (retval) {
		amba_driver_unregister(&etb_driver);
		printk(KERN_ERR "Failed to probe etm\n");
		return retval;
	}

	/* not being able to install this handler is not fatal */
	(void)register_sysrq_key('v', &sysrq_etm_op);

	return 0;
}

device_initcall(etm_init);