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