2 * linux/arch/arm/kernel/etm.c
4 * Driver for ARM's Embedded Trace Macrocell and Embedded Trace Buffer.
6 * Copyright (C) 2009 Nokia Corporation.
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.
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/types.h>
18 #include <linux/sysrq.h>
19 #include <linux/device.h>
20 #include <linux/clk.h>
21 #include <linux/amba/bus.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>
31 MODULE_LICENSE("GPL");
32 MODULE_AUTHOR("Alexander Shishkin");
38 unsigned int etb_bufsz;
39 void __iomem *etb_regs;
40 void __iomem *etm_regs;
49 static struct tracectx tracer;
51 static inline bool trace_isrunning(struct tracectx *t)
53 return !!(t->flags & TRACER_RUNNING);
56 static int etm_setup_address_range(struct tracectx *t, int n,
57 unsigned long start, unsigned long end, int exclude, int data)
59 u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
62 if (n < 1 || n > t->ncmppairs)
65 /* comparators and ranges are numbered starting with 1 as opposed
66 * to bits in a word */
70 flags |= ETMAAT_DLOADSTORE;
72 flags |= ETMAAT_IEXEC;
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));
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));
82 flags = exclude ? ETMTE_INCLEXCL : 0;
83 etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);
88 static int trace_start(struct tracectx *t)
91 unsigned long timeout = TRACER_TIMEOUT;
95 etb_writel(t, 0, ETBR_FORMATTERCTRL);
96 etb_writel(t, 1, ETBR_CTRL);
101 v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);
103 if (t->flags & TRACER_CYCLE_ACC)
104 v |= ETMCTRL_CYCLEACCURATE;
108 etm_writel(t, v, ETMR_CTRL);
110 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
113 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
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);
124 v &= ~ETMCTRL_PROGRAM;
125 v |= ETMCTRL_PORTSEL;
127 etm_writel(t, v, ETMR_CTRL);
129 timeout = TRACER_TIMEOUT;
130 while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
133 dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
140 t->flags |= TRACER_RUNNING;
145 static int trace_stop(struct tracectx *t)
147 unsigned long timeout = TRACER_TIMEOUT;
151 etm_writel(t, 0x440, ETMR_CTRL);
152 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
155 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
163 etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);
165 timeout = TRACER_TIMEOUT;
166 while (etb_readl(t, ETBR_FORMATTERCTRL) &
167 ETBFF_MANUAL_FLUSH && --timeout)
170 dev_dbg(t->dev, "Waiting for formatter flush to commence "
176 etb_writel(t, 0, ETBR_CTRL);
180 t->flags &= ~TRACER_RUNNING;
185 static int etb_getdatalen(struct tracectx *t)
190 v = etb_readl(t, ETBR_STATUS);
195 rp = etb_readl(t, ETBR_READADDR);
196 wp = etb_readl(t, ETBR_WRITEADDR);
199 etb_writel(t, 0, ETBR_READADDR);
200 etb_writel(t, 0, ETBR_WRITEADDR);
208 /* sysrq+v will always stop the running trace and leave it at that */
209 static void etm_dump(void)
211 struct tracectx *t = &tracer;
216 printk(KERN_INFO "No tracing hardware found\n");
220 if (trace_isrunning(t))
225 length = etb_getdatalen(t);
227 if (length == t->etb_bufsz)
228 first = etb_readl(t, ETBR_WRITEADDR);
230 etb_writel(t, first, ETBR_READADDR);
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");
238 /* deassert the overflow bit */
239 etb_writel(t, 1, ETBR_CTRL);
240 etb_writel(t, 0, ETBR_CTRL);
242 etb_writel(t, 0, ETBR_TRIGGERCOUNT);
243 etb_writel(t, 0, ETBR_READADDR);
244 etb_writel(t, 0, ETBR_WRITEADDR);
249 static void sysrq_etm_dump(int key)
251 dev_dbg(tracer.dev, "Dumping ETB buffer\n");
255 static struct sysrq_key_op sysrq_etm_op = {
256 .handler = sysrq_etm_dump,
257 .help_msg = "etm-buffer-dump(v)",
261 static int etb_open(struct inode *inode, struct file *file)
263 if (!tracer.etb_regs)
266 file->private_data = &tracer;
268 return nonseekable_open(inode, file);
271 static ssize_t etb_read(struct file *file, char __user *data,
272 size_t len, loff_t *ppos)
276 struct tracectx *t = file->private_data;
280 mutex_lock(&t->mutex);
282 if (trace_isrunning(t)) {
289 total = etb_getdatalen(t);
290 if (total == t->etb_bufsz)
291 first = etb_readl(t, ETBR_WRITEADDR);
293 etb_writel(t, first, ETBR_READADDR);
295 length = min(total * 4, (int)len);
296 buf = vmalloc(length);
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);
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);
307 etb_writel(t, 0, ETBR_WRITEADDR);
308 etb_writel(t, 0, ETBR_READADDR);
309 etb_writel(t, 0, ETBR_TRIGGERCOUNT);
313 length -= copy_to_user(data, buf, length);
317 mutex_unlock(&t->mutex);
322 static int etb_release(struct inode *inode, struct file *file)
324 /* there's nothing to do here, actually */
328 static const struct file_operations etb_fops = {
329 .owner = THIS_MODULE,
332 .release = etb_release,
336 static struct miscdevice etb_miscdev = {
342 static int etb_probe(struct amba_device *dev, const struct amba_id *id)
344 struct tracectx *t = &tracer;
347 ret = amba_request_regions(dev, NULL);
351 t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
357 amba_set_drvdata(dev, t);
359 etb_miscdev.parent = &dev->dev;
361 ret = misc_register(&etb_miscdev);
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");
371 clk_enable(t->emu_clk);
374 t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
375 dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);
377 /* make sure trace capture is disabled */
378 etb_writel(t, 0, ETBR_CTRL);
379 etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
382 dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");
388 iounmap(t->etb_regs);
391 amba_release_regions(dev);
396 static int etb_remove(struct amba_device *dev)
398 struct tracectx *t = amba_get_drvdata(dev);
400 iounmap(t->etb_regs);
403 clk_disable(t->emu_clk);
406 amba_release_regions(dev);
411 static struct amba_id etb_ids[] = {
419 static struct amba_driver etb_driver = {
422 .owner = THIS_MODULE,
425 .remove = etb_remove,
429 /* use a sysfs file "trace_running" to start/stop tracing */
430 static ssize_t trace_running_show(struct kobject *kobj,
431 struct kobj_attribute *attr,
434 return sprintf(buf, "%x\n", trace_isrunning(&tracer));
437 static ssize_t trace_running_store(struct kobject *kobj,
438 struct kobj_attribute *attr,
439 const char *buf, size_t n)
444 if (sscanf(buf, "%u", &value) != 1)
447 mutex_lock(&tracer.mutex);
448 ret = value ? trace_start(&tracer) : trace_stop(&tracer);
449 mutex_unlock(&tracer.mutex);
454 static struct kobj_attribute trace_running_attr =
455 __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
457 static ssize_t trace_info_show(struct kobject *kobj,
458 struct kobj_attribute *attr,
461 u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
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);
473 etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
474 etm_st = etm_readl(&tracer, ETMR_STATUS);
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"
483 "ETMR_STATUS:\t%08x\n",
495 static struct kobj_attribute trace_info_attr =
496 __ATTR(trace_info, 0444, trace_info_show, NULL);
498 static ssize_t trace_mode_show(struct kobject *kobj,
499 struct kobj_attribute *attr,
502 return sprintf(buf, "%d %d\n",
503 !!(tracer.flags & TRACER_CYCLE_ACC),
507 static ssize_t trace_mode_store(struct kobject *kobj,
508 struct kobj_attribute *attr,
509 const char *buf, size_t n)
511 unsigned int cycacc, portsz;
513 if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
516 mutex_lock(&tracer.mutex);
518 tracer.flags |= TRACER_CYCLE_ACC;
520 tracer.flags &= ~TRACER_CYCLE_ACC;
522 tracer.etm_portsz = portsz & 0x0f;
523 mutex_unlock(&tracer.mutex);
528 static struct kobj_attribute trace_mode_attr =
529 __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
531 static int etm_probe(struct amba_device *dev, const struct amba_id *id)
533 struct tracectx *t = &tracer;
537 dev_dbg(&dev->dev, "ETM already initialized\n");
542 ret = amba_request_regions(dev, NULL);
546 t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
552 amba_set_drvdata(dev, t);
554 mutex_init(&t->mutex);
556 t->flags = TRACER_CYCLE_ACC;
560 (void)etm_readl(t, ETMMR_PDSR);
561 /* dummy first read */
562 (void)etm_readl(&tracer, ETMMR_OSSRR);
564 t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
565 etm_writel(t, 0x440, ETMR_CTRL);
568 ret = sysfs_create_file(&dev->dev.kobj,
569 &trace_running_attr.attr);
573 /* failing to create any of these two is not fatal */
574 ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
576 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
578 ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
580 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
582 dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
588 iounmap(t->etm_regs);
591 amba_release_regions(dev);
596 static int etm_remove(struct amba_device *dev)
598 struct tracectx *t = amba_get_drvdata(dev);
600 iounmap(t->etm_regs);
603 amba_release_regions(dev);
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);
612 static struct amba_id etm_ids[] = {
620 static struct amba_driver etm_driver = {
623 .owner = THIS_MODULE,
626 .remove = etm_remove,
630 static int __init etm_init(void)
634 retval = amba_driver_register(&etb_driver);
636 printk(KERN_ERR "Failed to register etb\n");
640 retval = amba_driver_register(&etm_driver);
642 amba_driver_unregister(&etb_driver);
643 printk(KERN_ERR "Failed to probe etm\n");
647 /* not being able to install this handler is not fatal */
648 (void)register_sysrq_key('v', &sysrq_etm_op);
653 device_initcall(etm_init);