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
31 MODULE_LICENSE("GPL");
32 MODULE_AUTHOR("Alexander Shishkin");
33
34 /*
35 * ETM tracer state
36 */
37 struct 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
49 static struct tracectx tracer;
50
trace_isrunning(struct tracectx * t)51 static inline bool trace_isrunning(struct tracectx *t)
52 {
53 return !!(t->flags & TRACER_RUNNING);
54 }
55
etm_setup_address_range(struct tracectx * t,int n,unsigned long start,unsigned long end,int exclude,int data)56 static 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
trace_start(struct tracectx * t)88 static 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
trace_stop(struct tracectx * t)145 static 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
etb_getdatalen(struct tracectx * t)185 static 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 */
etm_dump(void)209 static 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
sysrq_etm_dump(int key)249 static void sysrq_etm_dump(int key)
250 {
251 dev_dbg(tracer.dev, "Dumping ETB buffer\n");
252 etm_dump();
253 }
254
255 static struct sysrq_key_op sysrq_etm_op = {
256 .handler = sysrq_etm_dump,
257 .help_msg = "ETM buffer dump",
258 .action_msg = "etm",
259 };
260
etb_open(struct inode * inode,struct file * file)261 static 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
etb_read(struct file * file,char __user * data,size_t len,loff_t * ppos)271 static 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
316 out:
317 mutex_unlock(&t->mutex);
318
319 return length;
320 }
321
etb_release(struct inode * inode,struct file * file)322 static int etb_release(struct inode *inode, struct file *file)
323 {
324 /* there's nothing to do here, actually */
325 return 0;
326 }
327
328 static 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
336 static struct miscdevice etb_miscdev = {
337 .name = "tracebuf",
338 .minor = 0,
339 .fops = &etb_fops,
340 };
341
etb_probe(struct amba_device * dev,const struct amba_id * id)342 static int __devinit 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
384 out:
385 return ret;
386
387 out_unmap:
388 amba_set_drvdata(dev, NULL);
389 iounmap(t->etb_regs);
390
391 out_release:
392 amba_release_regions(dev);
393
394 return ret;
395 }
396
etb_remove(struct amba_device * dev)397 static int etb_remove(struct amba_device *dev)
398 {
399 struct tracectx *t = amba_get_drvdata(dev);
400
401 amba_set_drvdata(dev, NULL);
402
403 iounmap(t->etb_regs);
404 t->etb_regs = NULL;
405
406 clk_disable(t->emu_clk);
407 clk_put(t->emu_clk);
408
409 amba_release_regions(dev);
410
411 return 0;
412 }
413
414 static struct amba_id etb_ids[] = {
415 {
416 .id = 0x0003b907,
417 .mask = 0x0007ffff,
418 },
419 { 0, 0 },
420 };
421
422 static struct amba_driver etb_driver = {
423 .drv = {
424 .name = "etb",
425 .owner = THIS_MODULE,
426 },
427 .probe = etb_probe,
428 .remove = etb_remove,
429 .id_table = etb_ids,
430 };
431
432 /* use a sysfs file "trace_running" to start/stop tracing */
trace_running_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)433 static ssize_t trace_running_show(struct kobject *kobj,
434 struct kobj_attribute *attr,
435 char *buf)
436 {
437 return sprintf(buf, "%x\n", trace_isrunning(&tracer));
438 }
439
trace_running_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t n)440 static ssize_t trace_running_store(struct kobject *kobj,
441 struct kobj_attribute *attr,
442 const char *buf, size_t n)
443 {
444 unsigned int value;
445 int ret;
446
447 if (sscanf(buf, "%u", &value) != 1)
448 return -EINVAL;
449
450 mutex_lock(&tracer.mutex);
451 ret = value ? trace_start(&tracer) : trace_stop(&tracer);
452 mutex_unlock(&tracer.mutex);
453
454 return ret ? : n;
455 }
456
457 static struct kobj_attribute trace_running_attr =
458 __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
459
trace_info_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)460 static ssize_t trace_info_show(struct kobject *kobj,
461 struct kobj_attribute *attr,
462 char *buf)
463 {
464 u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
465 int datalen;
466
467 etb_unlock(&tracer);
468 datalen = etb_getdatalen(&tracer);
469 etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
470 etb_ra = etb_readl(&tracer, ETBR_READADDR);
471 etb_st = etb_readl(&tracer, ETBR_STATUS);
472 etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
473 etb_lock(&tracer);
474
475 etm_unlock(&tracer);
476 etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
477 etm_st = etm_readl(&tracer, ETMR_STATUS);
478 etm_lock(&tracer);
479
480 return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
481 "ETBR_WRITEADDR:\t%08x\n"
482 "ETBR_READADDR:\t%08x\n"
483 "ETBR_STATUS:\t%08x\n"
484 "ETBR_FORMATTERCTRL:\t%08x\n"
485 "ETMR_CTRL:\t%08x\n"
486 "ETMR_STATUS:\t%08x\n",
487 datalen,
488 tracer.ncmppairs,
489 etb_wa,
490 etb_ra,
491 etb_st,
492 etb_fc,
493 etm_ctrl,
494 etm_st
495 );
496 }
497
498 static struct kobj_attribute trace_info_attr =
499 __ATTR(trace_info, 0444, trace_info_show, NULL);
500
trace_mode_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)501 static ssize_t trace_mode_show(struct kobject *kobj,
502 struct kobj_attribute *attr,
503 char *buf)
504 {
505 return sprintf(buf, "%d %d\n",
506 !!(tracer.flags & TRACER_CYCLE_ACC),
507 tracer.etm_portsz);
508 }
509
trace_mode_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t n)510 static ssize_t trace_mode_store(struct kobject *kobj,
511 struct kobj_attribute *attr,
512 const char *buf, size_t n)
513 {
514 unsigned int cycacc, portsz;
515
516 if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
517 return -EINVAL;
518
519 mutex_lock(&tracer.mutex);
520 if (cycacc)
521 tracer.flags |= TRACER_CYCLE_ACC;
522 else
523 tracer.flags &= ~TRACER_CYCLE_ACC;
524
525 tracer.etm_portsz = portsz & 0x0f;
526 mutex_unlock(&tracer.mutex);
527
528 return n;
529 }
530
531 static struct kobj_attribute trace_mode_attr =
532 __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
533
etm_probe(struct amba_device * dev,const struct amba_id * id)534 static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id)
535 {
536 struct tracectx *t = &tracer;
537 int ret = 0;
538
539 if (t->etm_regs) {
540 dev_dbg(&dev->dev, "ETM already initialized\n");
541 ret = -EBUSY;
542 goto out;
543 }
544
545 ret = amba_request_regions(dev, NULL);
546 if (ret)
547 goto out;
548
549 t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
550 if (!t->etm_regs) {
551 ret = -ENOMEM;
552 goto out_release;
553 }
554
555 amba_set_drvdata(dev, t);
556
557 mutex_init(&t->mutex);
558 t->dev = &dev->dev;
559 t->flags = TRACER_CYCLE_ACC;
560 t->etm_portsz = 1;
561
562 etm_unlock(t);
563 (void)etm_readl(t, ETMMR_PDSR);
564 /* dummy first read */
565 (void)etm_readl(&tracer, ETMMR_OSSRR);
566
567 t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
568 etm_writel(t, 0x440, ETMR_CTRL);
569 etm_lock(t);
570
571 ret = sysfs_create_file(&dev->dev.kobj,
572 &trace_running_attr.attr);
573 if (ret)
574 goto out_unmap;
575
576 /* failing to create any of these two is not fatal */
577 ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
578 if (ret)
579 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
580
581 ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
582 if (ret)
583 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
584
585 dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
586
587 out:
588 return ret;
589
590 out_unmap:
591 amba_set_drvdata(dev, NULL);
592 iounmap(t->etm_regs);
593
594 out_release:
595 amba_release_regions(dev);
596
597 return ret;
598 }
599
etm_remove(struct amba_device * dev)600 static int etm_remove(struct amba_device *dev)
601 {
602 struct tracectx *t = amba_get_drvdata(dev);
603
604 amba_set_drvdata(dev, NULL);
605
606 iounmap(t->etm_regs);
607 t->etm_regs = NULL;
608
609 amba_release_regions(dev);
610
611 sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
612 sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
613 sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
614
615 return 0;
616 }
617
618 static struct amba_id etm_ids[] = {
619 {
620 .id = 0x0003b921,
621 .mask = 0x0007ffff,
622 },
623 { 0, 0 },
624 };
625
626 static struct amba_driver etm_driver = {
627 .drv = {
628 .name = "etm",
629 .owner = THIS_MODULE,
630 },
631 .probe = etm_probe,
632 .remove = etm_remove,
633 .id_table = etm_ids,
634 };
635
etm_init(void)636 static int __init etm_init(void)
637 {
638 int retval;
639
640 retval = amba_driver_register(&etb_driver);
641 if (retval) {
642 printk(KERN_ERR "Failed to register etb\n");
643 return retval;
644 }
645
646 retval = amba_driver_register(&etm_driver);
647 if (retval) {
648 amba_driver_unregister(&etb_driver);
649 printk(KERN_ERR "Failed to probe etm\n");
650 return retval;
651 }
652
653 /* not being able to install this handler is not fatal */
654 (void)register_sysrq_key('v', &sysrq_etm_op);
655
656 return 0;
657 }
658
659 device_initcall(etm_init);
660
661