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1/*
2 * linux/arch/arm/kernel/etm.c
3 *
4 * Driver for ARM's Embedded Trace Macrocell and Embedded Trace Buffer.
5 *
6 * Copyright (C) 2009 Nokia Corporation.
7 * Alexander Shishkin
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/types.h>
17#include <linux/io.h>
18#include <linux/sysrq.h>
19#include <linux/device.h>
20#include <linux/clk.h>
21#include <linux/amba/bus.h>
22#include <linux/fs.h>
23#include <linux/uaccess.h>
24#include <linux/miscdevice.h>
25#include <linux/vmalloc.h>
26#include <linux/mutex.h>
27#include <asm/hardware/coresight.h>
28#include <asm/sections.h>
29
30MODULE_LICENSE("GPL");
31MODULE_AUTHOR("Alexander Shishkin");
32
33/*
34 * ETM tracer state
35 */
36struct tracectx {
37 unsigned int etb_bufsz;
38 void __iomem *etb_regs;
39 void __iomem *etm_regs;
40 unsigned long flags;
41 int ncmppairs;
42 int etm_portsz;
43 struct device *dev;
44 struct clk *emu_clk;
45 struct mutex mutex;
46};
47
48static struct tracectx tracer;
49
50static inline bool trace_isrunning(struct tracectx *t)
51{
52 return !!(t->flags & TRACER_RUNNING);
53}
54
55static int etm_setup_address_range(struct tracectx *t, int n,
56 unsigned long start, unsigned long end, int exclude, int data)
57{
58 u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
59 ETMAAT_NOVALCMP;
60
61 if (n < 1 || n > t->ncmppairs)
62 return -EINVAL;
63
64 /* comparators and ranges are numbered starting with 1 as opposed
65 * to bits in a word */
66 n--;
67
68 if (data)
69 flags |= ETMAAT_DLOADSTORE;
70 else
71 flags |= ETMAAT_IEXEC;
72
73 /* first comparator for the range */
74 etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2));
75 etm_writel(t, start, ETMR_COMP_VAL(n * 2));
76
77 /* second comparator is right next to it */
78 etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1));
79 etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1));
80
81 flags = exclude ? ETMTE_INCLEXCL : 0;
82 etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);
83
84 return 0;
85}
86
87static int trace_start(struct tracectx *t)
88{
89 u32 v;
90 unsigned long timeout = TRACER_TIMEOUT;
91
92 etb_unlock(t);
93
94 etb_writel(t, 0, ETBR_FORMATTERCTRL);
95 etb_writel(t, 1, ETBR_CTRL);
96
97 etb_lock(t);
98
99 /* configure etm */
100 v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);
101
102 if (t->flags & TRACER_CYCLE_ACC)
103 v |= ETMCTRL_CYCLEACCURATE;
104
105 etm_unlock(t);
106
107 etm_writel(t, v, ETMR_CTRL);
108
109 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
110 ;
111 if (!timeout) {
112 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
113 etm_lock(t);
114 return -EFAULT;
115 }
116
117 etm_setup_address_range(t, 1, (unsigned long)_stext,
118 (unsigned long)_etext, 0, 0);
119 etm_writel(t, 0, ETMR_TRACEENCTRL2);
120 etm_writel(t, 0, ETMR_TRACESSCTRL);
121 etm_writel(t, 0x6f, ETMR_TRACEENEVT);
122
123 v &= ~ETMCTRL_PROGRAM;
124 v |= ETMCTRL_PORTSEL;
125
126 etm_writel(t, v, ETMR_CTRL);
127
128 timeout = TRACER_TIMEOUT;
129 while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
130 ;
131 if (!timeout) {
132 dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
133 etm_lock(t);
134 return -EFAULT;
135 }
136
137 etm_lock(t);
138
139 t->flags |= TRACER_RUNNING;
140
141 return 0;
142}
143
144static int trace_stop(struct tracectx *t)
145{
146 unsigned long timeout = TRACER_TIMEOUT;
147
148 etm_unlock(t);
149
150 etm_writel(t, 0x440, ETMR_CTRL);
151 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
152 ;
153 if (!timeout) {
154 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
155 etm_lock(t);
156 return -EFAULT;
157 }
158
159 etm_lock(t);
160
161 etb_unlock(t);
162 etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);
163
164 timeout = TRACER_TIMEOUT;
165 while (etb_readl(t, ETBR_FORMATTERCTRL) &
166 ETBFF_MANUAL_FLUSH && --timeout)
167 ;
168 if (!timeout) {
169 dev_dbg(t->dev, "Waiting for formatter flush to commence "
170 "timed out\n");
171 etb_lock(t);
172 return -EFAULT;
173 }
174
175 etb_writel(t, 0, ETBR_CTRL);
176
177 etb_lock(t);
178
179 t->flags &= ~TRACER_RUNNING;
180
181 return 0;
182}
183
184static int etb_getdatalen(struct tracectx *t)
185{
186 u32 v;
187 int rp, wp;
188
189 v = etb_readl(t, ETBR_STATUS);
190
191 if (v & 1)
192 return t->etb_bufsz;
193
194 rp = etb_readl(t, ETBR_READADDR);
195 wp = etb_readl(t, ETBR_WRITEADDR);
196
197 if (rp > wp) {
198 etb_writel(t, 0, ETBR_READADDR);
199 etb_writel(t, 0, ETBR_WRITEADDR);
200
201 return 0;
202 }
203
204 return wp - rp;
205}
206
207/* sysrq+v will always stop the running trace and leave it at that */
208static void etm_dump(void)
209{
210 struct tracectx *t = &tracer;
211 u32 first = 0;
212 int length;
213
214 if (!t->etb_regs) {
215 printk(KERN_INFO "No tracing hardware found\n");
216 return;
217 }
218
219 if (trace_isrunning(t))
220 trace_stop(t);
221
222 etb_unlock(t);
223
224 length = etb_getdatalen(t);
225
226 if (length == t->etb_bufsz)
227 first = etb_readl(t, ETBR_WRITEADDR);
228
229 etb_writel(t, first, ETBR_READADDR);
230
231 printk(KERN_INFO "Trace buffer contents length: %d\n", length);
232 printk(KERN_INFO "--- ETB buffer begin ---\n");
233 for (; length; length--)
234 printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM)));
235 printk(KERN_INFO "\n--- ETB buffer end ---\n");
236
237 /* deassert the overflow bit */
238 etb_writel(t, 1, ETBR_CTRL);
239 etb_writel(t, 0, ETBR_CTRL);
240
241 etb_writel(t, 0, ETBR_TRIGGERCOUNT);
242 etb_writel(t, 0, ETBR_READADDR);
243 etb_writel(t, 0, ETBR_WRITEADDR);
244
245 etb_lock(t);
246}
247
248static void sysrq_etm_dump(int key)
249{
250 dev_dbg(tracer.dev, "Dumping ETB buffer\n");
251 etm_dump();
252}
253
254static struct sysrq_key_op sysrq_etm_op = {
255 .handler = sysrq_etm_dump,
256 .help_msg = "ETM buffer dump",
257 .action_msg = "etm",
258};
259
260static int etb_open(struct inode *inode, struct file *file)
261{
262 if (!tracer.etb_regs)
263 return -ENODEV;
264
265 file->private_data = &tracer;
266
267 return nonseekable_open(inode, file);
268}
269
270static ssize_t etb_read(struct file *file, char __user *data,
271 size_t len, loff_t *ppos)
272{
273 int total, i;
274 long length;
275 struct tracectx *t = file->private_data;
276 u32 first = 0;
277 u32 *buf;
278
279 mutex_lock(&t->mutex);
280
281 if (trace_isrunning(t)) {
282 length = 0;
283 goto out;
284 }
285
286 etb_unlock(t);
287
288 total = etb_getdatalen(t);
289 if (total == t->etb_bufsz)
290 first = etb_readl(t, ETBR_WRITEADDR);
291
292 etb_writel(t, first, ETBR_READADDR);
293
294 length = min(total * 4, (int)len);
295 buf = vmalloc(length);
296
297 dev_dbg(t->dev, "ETB buffer length: %d\n", total);
298 dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
299 for (i = 0; i < length / 4; i++)
300 buf[i] = etb_readl(t, ETBR_READMEM);
301
302 /* the only way to deassert overflow bit in ETB status is this */
303 etb_writel(t, 1, ETBR_CTRL);
304 etb_writel(t, 0, ETBR_CTRL);
305
306 etb_writel(t, 0, ETBR_WRITEADDR);
307 etb_writel(t, 0, ETBR_READADDR);
308 etb_writel(t, 0, ETBR_TRIGGERCOUNT);
309
310 etb_lock(t);
311
312 length -= copy_to_user(data, buf, length);
313 vfree(buf);
314
315out:
316 mutex_unlock(&t->mutex);
317
318 return length;
319}
320
321static int etb_release(struct inode *inode, struct file *file)
322{
323 /* there's nothing to do here, actually */
324 return 0;
325}
326
327static const struct file_operations etb_fops = {
328 .owner = THIS_MODULE,
329 .read = etb_read,
330 .open = etb_open,
331 .release = etb_release,
332 .llseek = no_llseek,
333};
334
335static struct miscdevice etb_miscdev = {
336 .name = "tracebuf",
337 .minor = 0,
338 .fops = &etb_fops,
339};
340
341static int __devinit etb_probe(struct amba_device *dev, const struct amba_id *id)
342{
343 struct tracectx *t = &tracer;
344 int ret = 0;
345
346 ret = amba_request_regions(dev, NULL);
347 if (ret)
348 goto out;
349
350 t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
351 if (!t->etb_regs) {
352 ret = -ENOMEM;
353 goto out_release;
354 }
355
356 amba_set_drvdata(dev, t);
357
358 etb_miscdev.parent = &dev->dev;
359
360 ret = misc_register(&etb_miscdev);
361 if (ret)
362 goto out_unmap;
363
364 t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
365 if (IS_ERR(t->emu_clk)) {
366 dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
367 return -EFAULT;
368 }
369
370 clk_enable(t->emu_clk);
371
372 etb_unlock(t);
373 t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
374 dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);
375
376 /* make sure trace capture is disabled */
377 etb_writel(t, 0, ETBR_CTRL);
378 etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
379 etb_lock(t);
380
381 dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");
382
383out:
384 return ret;
385
386out_unmap:
387 amba_set_drvdata(dev, NULL);
388 iounmap(t->etb_regs);
389
390out_release:
391 amba_release_regions(dev);
392
393 return ret;
394}
395
396static int etb_remove(struct amba_device *dev)
397{
398 struct tracectx *t = amba_get_drvdata(dev);
399
400 amba_set_drvdata(dev, NULL);
401
402 iounmap(t->etb_regs);
403 t->etb_regs = NULL;
404
405 clk_disable(t->emu_clk);
406 clk_put(t->emu_clk);
407
408 amba_release_regions(dev);
409
410 return 0;
411}
412
413static struct amba_id etb_ids[] = {
414 {
415 .id = 0x0003b907,
416 .mask = 0x0007ffff,
417 },
418 { 0, 0 },
419};
420
421static struct amba_driver etb_driver = {
422 .drv = {
423 .name = "etb",
424 .owner = THIS_MODULE,
425 },
426 .probe = etb_probe,
427 .remove = etb_remove,
428 .id_table = etb_ids,
429};
430
431/* use a sysfs file "trace_running" to start/stop tracing */
432static ssize_t trace_running_show(struct kobject *kobj,
433 struct kobj_attribute *attr,
434 char *buf)
435{
436 return sprintf(buf, "%x\n", trace_isrunning(&tracer));
437}
438
439static ssize_t trace_running_store(struct kobject *kobj,
440 struct kobj_attribute *attr,
441 const char *buf, size_t n)
442{
443 unsigned int value;
444 int ret;
445
446 if (sscanf(buf, "%u", &value) != 1)
447 return -EINVAL;
448
449 mutex_lock(&tracer.mutex);
450 ret = value ? trace_start(&tracer) : trace_stop(&tracer);
451 mutex_unlock(&tracer.mutex);
452
453 return ret ? : n;
454}
455
456static struct kobj_attribute trace_running_attr =
457 __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
458
459static ssize_t trace_info_show(struct kobject *kobj,
460 struct kobj_attribute *attr,
461 char *buf)
462{
463 u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
464 int datalen;
465
466 etb_unlock(&tracer);
467 datalen = etb_getdatalen(&tracer);
468 etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
469 etb_ra = etb_readl(&tracer, ETBR_READADDR);
470 etb_st = etb_readl(&tracer, ETBR_STATUS);
471 etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
472 etb_lock(&tracer);
473
474 etm_unlock(&tracer);
475 etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
476 etm_st = etm_readl(&tracer, ETMR_STATUS);
477 etm_lock(&tracer);
478
479 return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
480 "ETBR_WRITEADDR:\t%08x\n"
481 "ETBR_READADDR:\t%08x\n"
482 "ETBR_STATUS:\t%08x\n"
483 "ETBR_FORMATTERCTRL:\t%08x\n"
484 "ETMR_CTRL:\t%08x\n"
485 "ETMR_STATUS:\t%08x\n",
486 datalen,
487 tracer.ncmppairs,
488 etb_wa,
489 etb_ra,
490 etb_st,
491 etb_fc,
492 etm_ctrl,
493 etm_st
494 );
495}
496
497static struct kobj_attribute trace_info_attr =
498 __ATTR(trace_info, 0444, trace_info_show, NULL);
499
500static ssize_t trace_mode_show(struct kobject *kobj,
501 struct kobj_attribute *attr,
502 char *buf)
503{
504 return sprintf(buf, "%d %d\n",
505 !!(tracer.flags & TRACER_CYCLE_ACC),
506 tracer.etm_portsz);
507}
508
509static ssize_t trace_mode_store(struct kobject *kobj,
510 struct kobj_attribute *attr,
511 const char *buf, size_t n)
512{
513 unsigned int cycacc, portsz;
514
515 if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
516 return -EINVAL;
517
518 mutex_lock(&tracer.mutex);
519 if (cycacc)
520 tracer.flags |= TRACER_CYCLE_ACC;
521 else
522 tracer.flags &= ~TRACER_CYCLE_ACC;
523
524 tracer.etm_portsz = portsz & 0x0f;
525 mutex_unlock(&tracer.mutex);
526
527 return n;
528}
529
530static struct kobj_attribute trace_mode_attr =
531 __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
532
533static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id)
534{
535 struct tracectx *t = &tracer;
536 int ret = 0;
537
538 if (t->etm_regs) {
539 dev_dbg(&dev->dev, "ETM already initialized\n");
540 ret = -EBUSY;
541 goto out;
542 }
543
544 ret = amba_request_regions(dev, NULL);
545 if (ret)
546 goto out;
547
548 t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
549 if (!t->etm_regs) {
550 ret = -ENOMEM;
551 goto out_release;
552 }
553
554 amba_set_drvdata(dev, t);
555
556 mutex_init(&t->mutex);
557 t->dev = &dev->dev;
558 t->flags = TRACER_CYCLE_ACC;
559 t->etm_portsz = 1;
560
561 etm_unlock(t);
562 (void)etm_readl(t, ETMMR_PDSR);
563 /* dummy first read */
564 (void)etm_readl(&tracer, ETMMR_OSSRR);
565
566 t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
567 etm_writel(t, 0x440, ETMR_CTRL);
568 etm_lock(t);
569
570 ret = sysfs_create_file(&dev->dev.kobj,
571 &trace_running_attr.attr);
572 if (ret)
573 goto out_unmap;
574
575 /* failing to create any of these two is not fatal */
576 ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
577 if (ret)
578 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
579
580 ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
581 if (ret)
582 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
583
584 dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
585
586out:
587 return ret;
588
589out_unmap:
590 amba_set_drvdata(dev, NULL);
591 iounmap(t->etm_regs);
592
593out_release:
594 amba_release_regions(dev);
595
596 return ret;
597}
598
599static int etm_remove(struct amba_device *dev)
600{
601 struct tracectx *t = amba_get_drvdata(dev);
602
603 amba_set_drvdata(dev, NULL);
604
605 iounmap(t->etm_regs);
606 t->etm_regs = NULL;
607
608 amba_release_regions(dev);
609
610 sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
611 sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
612 sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
613
614 return 0;
615}
616
617static struct amba_id etm_ids[] = {
618 {
619 .id = 0x0003b921,
620 .mask = 0x0007ffff,
621 },
622 { 0, 0 },
623};
624
625static struct amba_driver etm_driver = {
626 .drv = {
627 .name = "etm",
628 .owner = THIS_MODULE,
629 },
630 .probe = etm_probe,
631 .remove = etm_remove,
632 .id_table = etm_ids,
633};
634
635static int __init etm_init(void)
636{
637 int retval;
638
639 retval = amba_driver_register(&etb_driver);
640 if (retval) {
641 printk(KERN_ERR "Failed to register etb\n");
642 return retval;
643 }
644
645 retval = amba_driver_register(&etm_driver);
646 if (retval) {
647 amba_driver_unregister(&etb_driver);
648 printk(KERN_ERR "Failed to probe etm\n");
649 return retval;
650 }
651
652 /* not being able to install this handler is not fatal */
653 (void)register_sysrq_key('v', &sysrq_etm_op);
654
655 return 0;
656}
657
658device_initcall(etm_init);
659