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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2017 Linaro Limited. All rights reserved.
4 *
5 * Author: Leo Yan <leo.yan@linaro.org>
6 */
7#include <linux/amba/bus.h>
8#include <linux/coresight.h>
9#include <linux/cpu.h>
10#include <linux/debugfs.h>
11#include <linux/delay.h>
12#include <linux/device.h>
13#include <linux/err.h>
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/iopoll.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/panic_notifier.h>
21#include <linux/pm_qos.h>
22#include <linux/slab.h>
23#include <linux/smp.h>
24#include <linux/types.h>
25#include <linux/uaccess.h>
26
27#include "coresight-priv.h"
28
29#define EDPCSR 0x0A0
30#define EDCIDSR 0x0A4
31#define EDVIDSR 0x0A8
32#define EDPCSR_HI 0x0AC
33#define EDOSLAR 0x300
34#define EDPRCR 0x310
35#define EDPRSR 0x314
36#define EDDEVID1 0xFC4
37#define EDDEVID 0xFC8
38
39#define EDPCSR_PROHIBITED 0xFFFFFFFF
40
41/* bits definition for EDPCSR */
42#define EDPCSR_THUMB BIT(0)
43#define EDPCSR_ARM_INST_MASK GENMASK(31, 2)
44#define EDPCSR_THUMB_INST_MASK GENMASK(31, 1)
45
46/* bits definition for EDPRCR */
47#define EDPRCR_COREPURQ BIT(3)
48#define EDPRCR_CORENPDRQ BIT(0)
49
50/* bits definition for EDPRSR */
51#define EDPRSR_DLK BIT(6)
52#define EDPRSR_PU BIT(0)
53
54/* bits definition for EDVIDSR */
55#define EDVIDSR_NS BIT(31)
56#define EDVIDSR_E2 BIT(30)
57#define EDVIDSR_E3 BIT(29)
58#define EDVIDSR_HV BIT(28)
59#define EDVIDSR_VMID GENMASK(7, 0)
60
61/*
62 * bits definition for EDDEVID1:PSCROffset
63 *
64 * NOTE: armv8 and armv7 have different definition for the register,
65 * so consolidate the bits definition as below:
66 *
67 * 0b0000 - Sample offset applies based on the instruction state, we
68 * rely on EDDEVID to check if EDPCSR is implemented or not
69 * 0b0001 - No offset applies.
70 * 0b0010 - No offset applies, but do not use in AArch32 mode
71 *
72 */
73#define EDDEVID1_PCSR_OFFSET_MASK GENMASK(3, 0)
74#define EDDEVID1_PCSR_OFFSET_INS_SET (0x0)
75#define EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32 (0x2)
76
77/* bits definition for EDDEVID */
78#define EDDEVID_PCSAMPLE_MODE GENMASK(3, 0)
79#define EDDEVID_IMPL_EDPCSR (0x1)
80#define EDDEVID_IMPL_EDPCSR_EDCIDSR (0x2)
81#define EDDEVID_IMPL_FULL (0x3)
82
83#define DEBUG_WAIT_SLEEP 1000
84#define DEBUG_WAIT_TIMEOUT 32000
85
86struct debug_drvdata {
87 void __iomem *base;
88 struct device *dev;
89 int cpu;
90
91 bool edpcsr_present;
92 bool edcidsr_present;
93 bool edvidsr_present;
94 bool pc_has_offset;
95
96 u32 edpcsr;
97 u32 edpcsr_hi;
98 u32 edprsr;
99 u32 edvidsr;
100 u32 edcidsr;
101};
102
103static DEFINE_MUTEX(debug_lock);
104static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata);
105static int debug_count;
106static struct dentry *debug_debugfs_dir;
107
108static bool debug_enable = IS_ENABLED(CONFIG_CORESIGHT_CPU_DEBUG_DEFAULT_ON);
109module_param_named(enable, debug_enable, bool, 0600);
110MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality");
111
112static void debug_os_unlock(struct debug_drvdata *drvdata)
113{
114 /* Unlocks the debug registers */
115 writel_relaxed(0x0, drvdata->base + EDOSLAR);
116
117 /* Make sure the registers are unlocked before accessing */
118 wmb();
119}
120
121/*
122 * According to ARM DDI 0487A.k, before access external debug
123 * registers should firstly check the access permission; if any
124 * below condition has been met then cannot access debug
125 * registers to avoid lockup issue:
126 *
127 * - CPU power domain is powered off;
128 * - The OS Double Lock is locked;
129 *
130 * By checking EDPRSR can get to know if meet these conditions.
131 */
132static bool debug_access_permitted(struct debug_drvdata *drvdata)
133{
134 /* CPU is powered off */
135 if (!(drvdata->edprsr & EDPRSR_PU))
136 return false;
137
138 /* The OS Double Lock is locked */
139 if (drvdata->edprsr & EDPRSR_DLK)
140 return false;
141
142 return true;
143}
144
145static void debug_force_cpu_powered_up(struct debug_drvdata *drvdata)
146{
147 u32 edprcr;
148
149try_again:
150
151 /*
152 * Send request to power management controller and assert
153 * DBGPWRUPREQ signal; if power management controller has
154 * sane implementation, it should enable CPU power domain
155 * in case CPU is in low power state.
156 */
157 edprcr = readl_relaxed(drvdata->base + EDPRCR);
158 edprcr |= EDPRCR_COREPURQ;
159 writel_relaxed(edprcr, drvdata->base + EDPRCR);
160
161 /* Wait for CPU to be powered up (timeout~=32ms) */
162 if (readx_poll_timeout_atomic(readl_relaxed, drvdata->base + EDPRSR,
163 drvdata->edprsr, (drvdata->edprsr & EDPRSR_PU),
164 DEBUG_WAIT_SLEEP, DEBUG_WAIT_TIMEOUT)) {
165 /*
166 * Unfortunately the CPU cannot be powered up, so return
167 * back and later has no permission to access other
168 * registers. For this case, should disable CPU low power
169 * states to ensure CPU power domain is enabled!
170 */
171 dev_err(drvdata->dev, "%s: power up request for CPU%d failed\n",
172 __func__, drvdata->cpu);
173 return;
174 }
175
176 /*
177 * At this point the CPU is powered up, so set the no powerdown
178 * request bit so we don't lose power and emulate power down.
179 */
180 edprcr = readl_relaxed(drvdata->base + EDPRCR);
181 edprcr |= EDPRCR_COREPURQ | EDPRCR_CORENPDRQ;
182 writel_relaxed(edprcr, drvdata->base + EDPRCR);
183
184 drvdata->edprsr = readl_relaxed(drvdata->base + EDPRSR);
185
186 /* The core power domain got switched off on use, try again */
187 if (unlikely(!(drvdata->edprsr & EDPRSR_PU)))
188 goto try_again;
189}
190
191static void debug_read_regs(struct debug_drvdata *drvdata)
192{
193 u32 save_edprcr;
194
195 CS_UNLOCK(drvdata->base);
196
197 /* Unlock os lock */
198 debug_os_unlock(drvdata);
199
200 /* Save EDPRCR register */
201 save_edprcr = readl_relaxed(drvdata->base + EDPRCR);
202
203 /*
204 * Ensure CPU power domain is enabled to let registers
205 * are accessiable.
206 */
207 debug_force_cpu_powered_up(drvdata);
208
209 if (!debug_access_permitted(drvdata))
210 goto out;
211
212 drvdata->edpcsr = readl_relaxed(drvdata->base + EDPCSR);
213
214 /*
215 * As described in ARM DDI 0487A.k, if the processing
216 * element (PE) is in debug state, or sample-based
217 * profiling is prohibited, EDPCSR reads as 0xFFFFFFFF;
218 * EDCIDSR, EDVIDSR and EDPCSR_HI registers also become
219 * UNKNOWN state. So directly bail out for this case.
220 */
221 if (drvdata->edpcsr == EDPCSR_PROHIBITED)
222 goto out;
223
224 /*
225 * A read of the EDPCSR normally has the side-effect of
226 * indirectly writing to EDCIDSR, EDVIDSR and EDPCSR_HI;
227 * at this point it's safe to read value from them.
228 */
229 if (IS_ENABLED(CONFIG_64BIT))
230 drvdata->edpcsr_hi = readl_relaxed(drvdata->base + EDPCSR_HI);
231
232 if (drvdata->edcidsr_present)
233 drvdata->edcidsr = readl_relaxed(drvdata->base + EDCIDSR);
234
235 if (drvdata->edvidsr_present)
236 drvdata->edvidsr = readl_relaxed(drvdata->base + EDVIDSR);
237
238out:
239 /* Restore EDPRCR register */
240 writel_relaxed(save_edprcr, drvdata->base + EDPRCR);
241
242 CS_LOCK(drvdata->base);
243}
244
245#ifdef CONFIG_64BIT
246static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata)
247{
248 return (unsigned long)drvdata->edpcsr_hi << 32 |
249 (unsigned long)drvdata->edpcsr;
250}
251#else
252static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata)
253{
254 unsigned long arm_inst_offset = 0, thumb_inst_offset = 0;
255 unsigned long pc;
256
257 pc = (unsigned long)drvdata->edpcsr;
258
259 if (drvdata->pc_has_offset) {
260 arm_inst_offset = 8;
261 thumb_inst_offset = 4;
262 }
263
264 /* Handle thumb instruction */
265 if (pc & EDPCSR_THUMB) {
266 pc = (pc & EDPCSR_THUMB_INST_MASK) - thumb_inst_offset;
267 return pc;
268 }
269
270 /*
271 * Handle arm instruction offset, if the arm instruction
272 * is not 4 byte alignment then it's possible the case
273 * for implementation defined; keep original value for this
274 * case and print info for notice.
275 */
276 if (pc & BIT(1))
277 dev_emerg(drvdata->dev,
278 "Instruction offset is implementation defined\n");
279 else
280 pc = (pc & EDPCSR_ARM_INST_MASK) - arm_inst_offset;
281
282 return pc;
283}
284#endif
285
286static void debug_dump_regs(struct debug_drvdata *drvdata)
287{
288 struct device *dev = drvdata->dev;
289 unsigned long pc;
290
291 dev_emerg(dev, " EDPRSR: %08x (Power:%s DLK:%s)\n",
292 drvdata->edprsr,
293 drvdata->edprsr & EDPRSR_PU ? "On" : "Off",
294 drvdata->edprsr & EDPRSR_DLK ? "Lock" : "Unlock");
295
296 if (!debug_access_permitted(drvdata)) {
297 dev_emerg(dev, "No permission to access debug registers!\n");
298 return;
299 }
300
301 if (drvdata->edpcsr == EDPCSR_PROHIBITED) {
302 dev_emerg(dev, "CPU is in Debug state or profiling is prohibited!\n");
303 return;
304 }
305
306 pc = debug_adjust_pc(drvdata);
307 dev_emerg(dev, " EDPCSR: %pS\n", (void *)pc);
308
309 if (drvdata->edcidsr_present)
310 dev_emerg(dev, " EDCIDSR: %08x\n", drvdata->edcidsr);
311
312 if (drvdata->edvidsr_present)
313 dev_emerg(dev, " EDVIDSR: %08x (State:%s Mode:%s Width:%dbits VMID:%x)\n",
314 drvdata->edvidsr,
315 drvdata->edvidsr & EDVIDSR_NS ?
316 "Non-secure" : "Secure",
317 drvdata->edvidsr & EDVIDSR_E3 ? "EL3" :
318 (drvdata->edvidsr & EDVIDSR_E2 ?
319 "EL2" : "EL1/0"),
320 drvdata->edvidsr & EDVIDSR_HV ? 64 : 32,
321 drvdata->edvidsr & (u32)EDVIDSR_VMID);
322}
323
324static void debug_init_arch_data(void *info)
325{
326 struct debug_drvdata *drvdata = info;
327 u32 mode, pcsr_offset;
328 u32 eddevid, eddevid1;
329
330 CS_UNLOCK(drvdata->base);
331
332 /* Read device info */
333 eddevid = readl_relaxed(drvdata->base + EDDEVID);
334 eddevid1 = readl_relaxed(drvdata->base + EDDEVID1);
335
336 CS_LOCK(drvdata->base);
337
338 /* Parse implementation feature */
339 mode = eddevid & EDDEVID_PCSAMPLE_MODE;
340 pcsr_offset = eddevid1 & EDDEVID1_PCSR_OFFSET_MASK;
341
342 drvdata->edpcsr_present = false;
343 drvdata->edcidsr_present = false;
344 drvdata->edvidsr_present = false;
345 drvdata->pc_has_offset = false;
346
347 switch (mode) {
348 case EDDEVID_IMPL_FULL:
349 drvdata->edvidsr_present = true;
350 fallthrough;
351 case EDDEVID_IMPL_EDPCSR_EDCIDSR:
352 drvdata->edcidsr_present = true;
353 fallthrough;
354 case EDDEVID_IMPL_EDPCSR:
355 /*
356 * In ARM DDI 0487A.k, the EDDEVID1.PCSROffset is used to
357 * define if has the offset for PC sampling value; if read
358 * back EDDEVID1.PCSROffset == 0x2, then this means the debug
359 * module does not sample the instruction set state when
360 * armv8 CPU in AArch32 state.
361 */
362 drvdata->edpcsr_present =
363 ((IS_ENABLED(CONFIG_64BIT) && pcsr_offset != 0) ||
364 (pcsr_offset != EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32));
365
366 drvdata->pc_has_offset =
367 (pcsr_offset == EDDEVID1_PCSR_OFFSET_INS_SET);
368 break;
369 default:
370 break;
371 }
372}
373
374/*
375 * Dump out information on panic.
376 */
377static int debug_notifier_call(struct notifier_block *self,
378 unsigned long v, void *p)
379{
380 int cpu;
381 struct debug_drvdata *drvdata;
382
383 /* Bail out if we can't acquire the mutex or the functionality is off */
384 if (!mutex_trylock(&debug_lock))
385 return NOTIFY_DONE;
386
387 if (!debug_enable)
388 goto skip_dump;
389
390 pr_emerg("ARM external debug module:\n");
391
392 for_each_possible_cpu(cpu) {
393 drvdata = per_cpu(debug_drvdata, cpu);
394 if (!drvdata)
395 continue;
396
397 dev_emerg(drvdata->dev, "CPU[%d]:\n", drvdata->cpu);
398
399 debug_read_regs(drvdata);
400 debug_dump_regs(drvdata);
401 }
402
403skip_dump:
404 mutex_unlock(&debug_lock);
405 return NOTIFY_DONE;
406}
407
408static struct notifier_block debug_notifier = {
409 .notifier_call = debug_notifier_call,
410};
411
412static int debug_enable_func(void)
413{
414 struct debug_drvdata *drvdata;
415 int cpu, ret = 0;
416 cpumask_t mask;
417
418 /*
419 * Use cpumask to track which debug power domains have
420 * been powered on and use it to handle failure case.
421 */
422 cpumask_clear(&mask);
423
424 for_each_possible_cpu(cpu) {
425 drvdata = per_cpu(debug_drvdata, cpu);
426 if (!drvdata)
427 continue;
428
429 ret = pm_runtime_get_sync(drvdata->dev);
430 if (ret < 0)
431 goto err;
432 else
433 cpumask_set_cpu(cpu, &mask);
434 }
435
436 return 0;
437
438err:
439 /*
440 * If pm_runtime_get_sync() has failed, need rollback on
441 * all the other CPUs that have been enabled before that.
442 */
443 for_each_cpu(cpu, &mask) {
444 drvdata = per_cpu(debug_drvdata, cpu);
445 pm_runtime_put_noidle(drvdata->dev);
446 }
447
448 return ret;
449}
450
451static int debug_disable_func(void)
452{
453 struct debug_drvdata *drvdata;
454 int cpu, ret, err = 0;
455
456 /*
457 * Disable debug power domains, records the error and keep
458 * circling through all other CPUs when an error has been
459 * encountered.
460 */
461 for_each_possible_cpu(cpu) {
462 drvdata = per_cpu(debug_drvdata, cpu);
463 if (!drvdata)
464 continue;
465
466 ret = pm_runtime_put(drvdata->dev);
467 if (ret < 0)
468 err = ret;
469 }
470
471 return err;
472}
473
474static ssize_t debug_func_knob_write(struct file *f,
475 const char __user *buf, size_t count, loff_t *ppos)
476{
477 u8 val;
478 int ret;
479
480 ret = kstrtou8_from_user(buf, count, 2, &val);
481 if (ret)
482 return ret;
483
484 mutex_lock(&debug_lock);
485
486 if (val == debug_enable)
487 goto out;
488
489 if (val)
490 ret = debug_enable_func();
491 else
492 ret = debug_disable_func();
493
494 if (ret) {
495 pr_err("%s: unable to %s debug function: %d\n",
496 __func__, val ? "enable" : "disable", ret);
497 goto err;
498 }
499
500 debug_enable = val;
501out:
502 ret = count;
503err:
504 mutex_unlock(&debug_lock);
505 return ret;
506}
507
508static ssize_t debug_func_knob_read(struct file *f,
509 char __user *ubuf, size_t count, loff_t *ppos)
510{
511 ssize_t ret;
512 char buf[3];
513
514 mutex_lock(&debug_lock);
515 snprintf(buf, sizeof(buf), "%d\n", debug_enable);
516 mutex_unlock(&debug_lock);
517
518 ret = simple_read_from_buffer(ubuf, count, ppos, buf, sizeof(buf));
519 return ret;
520}
521
522static const struct file_operations debug_func_knob_fops = {
523 .open = simple_open,
524 .read = debug_func_knob_read,
525 .write = debug_func_knob_write,
526};
527
528static int debug_func_init(void)
529{
530 int ret;
531
532 /* Create debugfs node */
533 debug_debugfs_dir = debugfs_create_dir("coresight_cpu_debug", NULL);
534 debugfs_create_file("enable", 0644, debug_debugfs_dir, NULL,
535 &debug_func_knob_fops);
536
537 /* Register function to be called for panic */
538 ret = atomic_notifier_chain_register(&panic_notifier_list,
539 &debug_notifier);
540 if (ret) {
541 pr_err("%s: unable to register notifier: %d\n",
542 __func__, ret);
543 goto err;
544 }
545
546 return 0;
547
548err:
549 debugfs_remove_recursive(debug_debugfs_dir);
550 return ret;
551}
552
553static void debug_func_exit(void)
554{
555 atomic_notifier_chain_unregister(&panic_notifier_list,
556 &debug_notifier);
557 debugfs_remove_recursive(debug_debugfs_dir);
558}
559
560static int debug_probe(struct amba_device *adev, const struct amba_id *id)
561{
562 void __iomem *base;
563 struct device *dev = &adev->dev;
564 struct debug_drvdata *drvdata;
565 struct resource *res = &adev->res;
566 int ret;
567
568 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
569 if (!drvdata)
570 return -ENOMEM;
571
572 drvdata->cpu = coresight_get_cpu(dev);
573 if (drvdata->cpu < 0)
574 return drvdata->cpu;
575
576 if (per_cpu(debug_drvdata, drvdata->cpu)) {
577 dev_err(dev, "CPU%d drvdata has already been initialized\n",
578 drvdata->cpu);
579 return -EBUSY;
580 }
581
582 drvdata->dev = &adev->dev;
583 amba_set_drvdata(adev, drvdata);
584
585 /* Validity for the resource is already checked by the AMBA core */
586 base = devm_ioremap_resource(dev, res);
587 if (IS_ERR(base))
588 return PTR_ERR(base);
589
590 drvdata->base = base;
591
592 cpus_read_lock();
593 per_cpu(debug_drvdata, drvdata->cpu) = drvdata;
594 ret = smp_call_function_single(drvdata->cpu, debug_init_arch_data,
595 drvdata, 1);
596 cpus_read_unlock();
597
598 if (ret) {
599 dev_err(dev, "CPU%d debug arch init failed\n", drvdata->cpu);
600 goto err;
601 }
602
603 if (!drvdata->edpcsr_present) {
604 dev_err(dev, "CPU%d sample-based profiling isn't implemented\n",
605 drvdata->cpu);
606 ret = -ENXIO;
607 goto err;
608 }
609
610 if (!debug_count++) {
611 ret = debug_func_init();
612 if (ret)
613 goto err_func_init;
614 }
615
616 mutex_lock(&debug_lock);
617 /* Turn off debug power domain if debugging is disabled */
618 if (!debug_enable)
619 pm_runtime_put(dev);
620 mutex_unlock(&debug_lock);
621
622 dev_info(dev, "Coresight debug-CPU%d initialized\n", drvdata->cpu);
623 return 0;
624
625err_func_init:
626 debug_count--;
627err:
628 per_cpu(debug_drvdata, drvdata->cpu) = NULL;
629 return ret;
630}
631
632static void debug_remove(struct amba_device *adev)
633{
634 struct device *dev = &adev->dev;
635 struct debug_drvdata *drvdata = amba_get_drvdata(adev);
636
637 per_cpu(debug_drvdata, drvdata->cpu) = NULL;
638
639 mutex_lock(&debug_lock);
640 /* Turn off debug power domain before rmmod the module */
641 if (debug_enable)
642 pm_runtime_put(dev);
643 mutex_unlock(&debug_lock);
644
645 if (!--debug_count)
646 debug_func_exit();
647}
648
649static const struct amba_cs_uci_id uci_id_debug[] = {
650 {
651 /* CPU Debug UCI data */
652 .devarch = 0x47706a15,
653 .devarch_mask = 0xfff0ffff,
654 .devtype = 0x00000015,
655 }
656};
657
658static const struct amba_id debug_ids[] = {
659 CS_AMBA_ID(0x000bbd03), /* Cortex-A53 */
660 CS_AMBA_ID(0x000bbd07), /* Cortex-A57 */
661 CS_AMBA_ID(0x000bbd08), /* Cortex-A72 */
662 CS_AMBA_ID(0x000bbd09), /* Cortex-A73 */
663 CS_AMBA_UCI_ID(0x000f0205, uci_id_debug), /* Qualcomm Kryo */
664 CS_AMBA_UCI_ID(0x000f0211, uci_id_debug), /* Qualcomm Kryo */
665 {},
666};
667
668MODULE_DEVICE_TABLE(amba, debug_ids);
669
670static struct amba_driver debug_driver = {
671 .drv = {
672 .name = "coresight-cpu-debug",
673 .suppress_bind_attrs = true,
674 },
675 .probe = debug_probe,
676 .remove = debug_remove,
677 .id_table = debug_ids,
678};
679
680module_amba_driver(debug_driver);
681
682MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
683MODULE_DESCRIPTION("ARM Coresight CPU Debug Driver");
684MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2017 Linaro Limited. All rights reserved.
4 *
5 * Author: Leo Yan <leo.yan@linaro.org>
6 */
7#include <linux/amba/bus.h>
8#include <linux/coresight.h>
9#include <linux/cpu.h>
10#include <linux/debugfs.h>
11#include <linux/delay.h>
12#include <linux/device.h>
13#include <linux/err.h>
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/iopoll.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/pm_qos.h>
21#include <linux/slab.h>
22#include <linux/smp.h>
23#include <linux/types.h>
24#include <linux/uaccess.h>
25
26#include "coresight-priv.h"
27
28#define EDPCSR 0x0A0
29#define EDCIDSR 0x0A4
30#define EDVIDSR 0x0A8
31#define EDPCSR_HI 0x0AC
32#define EDOSLAR 0x300
33#define EDPRCR 0x310
34#define EDPRSR 0x314
35#define EDDEVID1 0xFC4
36#define EDDEVID 0xFC8
37
38#define EDPCSR_PROHIBITED 0xFFFFFFFF
39
40/* bits definition for EDPCSR */
41#define EDPCSR_THUMB BIT(0)
42#define EDPCSR_ARM_INST_MASK GENMASK(31, 2)
43#define EDPCSR_THUMB_INST_MASK GENMASK(31, 1)
44
45/* bits definition for EDPRCR */
46#define EDPRCR_COREPURQ BIT(3)
47#define EDPRCR_CORENPDRQ BIT(0)
48
49/* bits definition for EDPRSR */
50#define EDPRSR_DLK BIT(6)
51#define EDPRSR_PU BIT(0)
52
53/* bits definition for EDVIDSR */
54#define EDVIDSR_NS BIT(31)
55#define EDVIDSR_E2 BIT(30)
56#define EDVIDSR_E3 BIT(29)
57#define EDVIDSR_HV BIT(28)
58#define EDVIDSR_VMID GENMASK(7, 0)
59
60/*
61 * bits definition for EDDEVID1:PSCROffset
62 *
63 * NOTE: armv8 and armv7 have different definition for the register,
64 * so consolidate the bits definition as below:
65 *
66 * 0b0000 - Sample offset applies based on the instruction state, we
67 * rely on EDDEVID to check if EDPCSR is implemented or not
68 * 0b0001 - No offset applies.
69 * 0b0010 - No offset applies, but do not use in AArch32 mode
70 *
71 */
72#define EDDEVID1_PCSR_OFFSET_MASK GENMASK(3, 0)
73#define EDDEVID1_PCSR_OFFSET_INS_SET (0x0)
74#define EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32 (0x2)
75
76/* bits definition for EDDEVID */
77#define EDDEVID_PCSAMPLE_MODE GENMASK(3, 0)
78#define EDDEVID_IMPL_EDPCSR (0x1)
79#define EDDEVID_IMPL_EDPCSR_EDCIDSR (0x2)
80#define EDDEVID_IMPL_FULL (0x3)
81
82#define DEBUG_WAIT_SLEEP 1000
83#define DEBUG_WAIT_TIMEOUT 32000
84
85struct debug_drvdata {
86 void __iomem *base;
87 struct device *dev;
88 int cpu;
89
90 bool edpcsr_present;
91 bool edcidsr_present;
92 bool edvidsr_present;
93 bool pc_has_offset;
94
95 u32 edpcsr;
96 u32 edpcsr_hi;
97 u32 edprsr;
98 u32 edvidsr;
99 u32 edcidsr;
100};
101
102static DEFINE_MUTEX(debug_lock);
103static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata);
104static int debug_count;
105static struct dentry *debug_debugfs_dir;
106
107static bool debug_enable;
108module_param_named(enable, debug_enable, bool, 0600);
109MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality");
110
111static void debug_os_unlock(struct debug_drvdata *drvdata)
112{
113 /* Unlocks the debug registers */
114 writel_relaxed(0x0, drvdata->base + EDOSLAR);
115
116 /* Make sure the registers are unlocked before accessing */
117 wmb();
118}
119
120/*
121 * According to ARM DDI 0487A.k, before access external debug
122 * registers should firstly check the access permission; if any
123 * below condition has been met then cannot access debug
124 * registers to avoid lockup issue:
125 *
126 * - CPU power domain is powered off;
127 * - The OS Double Lock is locked;
128 *
129 * By checking EDPRSR can get to know if meet these conditions.
130 */
131static bool debug_access_permitted(struct debug_drvdata *drvdata)
132{
133 /* CPU is powered off */
134 if (!(drvdata->edprsr & EDPRSR_PU))
135 return false;
136
137 /* The OS Double Lock is locked */
138 if (drvdata->edprsr & EDPRSR_DLK)
139 return false;
140
141 return true;
142}
143
144static void debug_force_cpu_powered_up(struct debug_drvdata *drvdata)
145{
146 u32 edprcr;
147
148try_again:
149
150 /*
151 * Send request to power management controller and assert
152 * DBGPWRUPREQ signal; if power management controller has
153 * sane implementation, it should enable CPU power domain
154 * in case CPU is in low power state.
155 */
156 edprcr = readl_relaxed(drvdata->base + EDPRCR);
157 edprcr |= EDPRCR_COREPURQ;
158 writel_relaxed(edprcr, drvdata->base + EDPRCR);
159
160 /* Wait for CPU to be powered up (timeout~=32ms) */
161 if (readx_poll_timeout_atomic(readl_relaxed, drvdata->base + EDPRSR,
162 drvdata->edprsr, (drvdata->edprsr & EDPRSR_PU),
163 DEBUG_WAIT_SLEEP, DEBUG_WAIT_TIMEOUT)) {
164 /*
165 * Unfortunately the CPU cannot be powered up, so return
166 * back and later has no permission to access other
167 * registers. For this case, should disable CPU low power
168 * states to ensure CPU power domain is enabled!
169 */
170 dev_err(drvdata->dev, "%s: power up request for CPU%d failed\n",
171 __func__, drvdata->cpu);
172 return;
173 }
174
175 /*
176 * At this point the CPU is powered up, so set the no powerdown
177 * request bit so we don't lose power and emulate power down.
178 */
179 edprcr = readl_relaxed(drvdata->base + EDPRCR);
180 edprcr |= EDPRCR_COREPURQ | EDPRCR_CORENPDRQ;
181 writel_relaxed(edprcr, drvdata->base + EDPRCR);
182
183 drvdata->edprsr = readl_relaxed(drvdata->base + EDPRSR);
184
185 /* The core power domain got switched off on use, try again */
186 if (unlikely(!(drvdata->edprsr & EDPRSR_PU)))
187 goto try_again;
188}
189
190static void debug_read_regs(struct debug_drvdata *drvdata)
191{
192 u32 save_edprcr;
193
194 CS_UNLOCK(drvdata->base);
195
196 /* Unlock os lock */
197 debug_os_unlock(drvdata);
198
199 /* Save EDPRCR register */
200 save_edprcr = readl_relaxed(drvdata->base + EDPRCR);
201
202 /*
203 * Ensure CPU power domain is enabled to let registers
204 * are accessiable.
205 */
206 debug_force_cpu_powered_up(drvdata);
207
208 if (!debug_access_permitted(drvdata))
209 goto out;
210
211 drvdata->edpcsr = readl_relaxed(drvdata->base + EDPCSR);
212
213 /*
214 * As described in ARM DDI 0487A.k, if the processing
215 * element (PE) is in debug state, or sample-based
216 * profiling is prohibited, EDPCSR reads as 0xFFFFFFFF;
217 * EDCIDSR, EDVIDSR and EDPCSR_HI registers also become
218 * UNKNOWN state. So directly bail out for this case.
219 */
220 if (drvdata->edpcsr == EDPCSR_PROHIBITED)
221 goto out;
222
223 /*
224 * A read of the EDPCSR normally has the side-effect of
225 * indirectly writing to EDCIDSR, EDVIDSR and EDPCSR_HI;
226 * at this point it's safe to read value from them.
227 */
228 if (IS_ENABLED(CONFIG_64BIT))
229 drvdata->edpcsr_hi = readl_relaxed(drvdata->base + EDPCSR_HI);
230
231 if (drvdata->edcidsr_present)
232 drvdata->edcidsr = readl_relaxed(drvdata->base + EDCIDSR);
233
234 if (drvdata->edvidsr_present)
235 drvdata->edvidsr = readl_relaxed(drvdata->base + EDVIDSR);
236
237out:
238 /* Restore EDPRCR register */
239 writel_relaxed(save_edprcr, drvdata->base + EDPRCR);
240
241 CS_LOCK(drvdata->base);
242}
243
244#ifdef CONFIG_64BIT
245static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata)
246{
247 return (unsigned long)drvdata->edpcsr_hi << 32 |
248 (unsigned long)drvdata->edpcsr;
249}
250#else
251static unsigned long debug_adjust_pc(struct debug_drvdata *drvdata)
252{
253 unsigned long arm_inst_offset = 0, thumb_inst_offset = 0;
254 unsigned long pc;
255
256 pc = (unsigned long)drvdata->edpcsr;
257
258 if (drvdata->pc_has_offset) {
259 arm_inst_offset = 8;
260 thumb_inst_offset = 4;
261 }
262
263 /* Handle thumb instruction */
264 if (pc & EDPCSR_THUMB) {
265 pc = (pc & EDPCSR_THUMB_INST_MASK) - thumb_inst_offset;
266 return pc;
267 }
268
269 /*
270 * Handle arm instruction offset, if the arm instruction
271 * is not 4 byte alignment then it's possible the case
272 * for implementation defined; keep original value for this
273 * case and print info for notice.
274 */
275 if (pc & BIT(1))
276 dev_emerg(drvdata->dev,
277 "Instruction offset is implementation defined\n");
278 else
279 pc = (pc & EDPCSR_ARM_INST_MASK) - arm_inst_offset;
280
281 return pc;
282}
283#endif
284
285static void debug_dump_regs(struct debug_drvdata *drvdata)
286{
287 struct device *dev = drvdata->dev;
288 unsigned long pc;
289
290 dev_emerg(dev, " EDPRSR: %08x (Power:%s DLK:%s)\n",
291 drvdata->edprsr,
292 drvdata->edprsr & EDPRSR_PU ? "On" : "Off",
293 drvdata->edprsr & EDPRSR_DLK ? "Lock" : "Unlock");
294
295 if (!debug_access_permitted(drvdata)) {
296 dev_emerg(dev, "No permission to access debug registers!\n");
297 return;
298 }
299
300 if (drvdata->edpcsr == EDPCSR_PROHIBITED) {
301 dev_emerg(dev, "CPU is in Debug state or profiling is prohibited!\n");
302 return;
303 }
304
305 pc = debug_adjust_pc(drvdata);
306 dev_emerg(dev, " EDPCSR: %pS\n", (void *)pc);
307
308 if (drvdata->edcidsr_present)
309 dev_emerg(dev, " EDCIDSR: %08x\n", drvdata->edcidsr);
310
311 if (drvdata->edvidsr_present)
312 dev_emerg(dev, " EDVIDSR: %08x (State:%s Mode:%s Width:%dbits VMID:%x)\n",
313 drvdata->edvidsr,
314 drvdata->edvidsr & EDVIDSR_NS ?
315 "Non-secure" : "Secure",
316 drvdata->edvidsr & EDVIDSR_E3 ? "EL3" :
317 (drvdata->edvidsr & EDVIDSR_E2 ?
318 "EL2" : "EL1/0"),
319 drvdata->edvidsr & EDVIDSR_HV ? 64 : 32,
320 drvdata->edvidsr & (u32)EDVIDSR_VMID);
321}
322
323static void debug_init_arch_data(void *info)
324{
325 struct debug_drvdata *drvdata = info;
326 u32 mode, pcsr_offset;
327 u32 eddevid, eddevid1;
328
329 CS_UNLOCK(drvdata->base);
330
331 /* Read device info */
332 eddevid = readl_relaxed(drvdata->base + EDDEVID);
333 eddevid1 = readl_relaxed(drvdata->base + EDDEVID1);
334
335 CS_LOCK(drvdata->base);
336
337 /* Parse implementation feature */
338 mode = eddevid & EDDEVID_PCSAMPLE_MODE;
339 pcsr_offset = eddevid1 & EDDEVID1_PCSR_OFFSET_MASK;
340
341 drvdata->edpcsr_present = false;
342 drvdata->edcidsr_present = false;
343 drvdata->edvidsr_present = false;
344 drvdata->pc_has_offset = false;
345
346 switch (mode) {
347 case EDDEVID_IMPL_FULL:
348 drvdata->edvidsr_present = true;
349 fallthrough;
350 case EDDEVID_IMPL_EDPCSR_EDCIDSR:
351 drvdata->edcidsr_present = true;
352 fallthrough;
353 case EDDEVID_IMPL_EDPCSR:
354 /*
355 * In ARM DDI 0487A.k, the EDDEVID1.PCSROffset is used to
356 * define if has the offset for PC sampling value; if read
357 * back EDDEVID1.PCSROffset == 0x2, then this means the debug
358 * module does not sample the instruction set state when
359 * armv8 CPU in AArch32 state.
360 */
361 drvdata->edpcsr_present =
362 ((IS_ENABLED(CONFIG_64BIT) && pcsr_offset != 0) ||
363 (pcsr_offset != EDDEVID1_PCSR_NO_OFFSET_DIS_AARCH32));
364
365 drvdata->pc_has_offset =
366 (pcsr_offset == EDDEVID1_PCSR_OFFSET_INS_SET);
367 break;
368 default:
369 break;
370 }
371}
372
373/*
374 * Dump out information on panic.
375 */
376static int debug_notifier_call(struct notifier_block *self,
377 unsigned long v, void *p)
378{
379 int cpu;
380 struct debug_drvdata *drvdata;
381
382 mutex_lock(&debug_lock);
383
384 /* Bail out if the functionality is disabled */
385 if (!debug_enable)
386 goto skip_dump;
387
388 pr_emerg("ARM external debug module:\n");
389
390 for_each_possible_cpu(cpu) {
391 drvdata = per_cpu(debug_drvdata, cpu);
392 if (!drvdata)
393 continue;
394
395 dev_emerg(drvdata->dev, "CPU[%d]:\n", drvdata->cpu);
396
397 debug_read_regs(drvdata);
398 debug_dump_regs(drvdata);
399 }
400
401skip_dump:
402 mutex_unlock(&debug_lock);
403 return 0;
404}
405
406static struct notifier_block debug_notifier = {
407 .notifier_call = debug_notifier_call,
408};
409
410static int debug_enable_func(void)
411{
412 struct debug_drvdata *drvdata;
413 int cpu, ret = 0;
414 cpumask_t mask;
415
416 /*
417 * Use cpumask to track which debug power domains have
418 * been powered on and use it to handle failure case.
419 */
420 cpumask_clear(&mask);
421
422 for_each_possible_cpu(cpu) {
423 drvdata = per_cpu(debug_drvdata, cpu);
424 if (!drvdata)
425 continue;
426
427 ret = pm_runtime_get_sync(drvdata->dev);
428 if (ret < 0)
429 goto err;
430 else
431 cpumask_set_cpu(cpu, &mask);
432 }
433
434 return 0;
435
436err:
437 /*
438 * If pm_runtime_get_sync() has failed, need rollback on
439 * all the other CPUs that have been enabled before that.
440 */
441 for_each_cpu(cpu, &mask) {
442 drvdata = per_cpu(debug_drvdata, cpu);
443 pm_runtime_put_noidle(drvdata->dev);
444 }
445
446 return ret;
447}
448
449static int debug_disable_func(void)
450{
451 struct debug_drvdata *drvdata;
452 int cpu, ret, err = 0;
453
454 /*
455 * Disable debug power domains, records the error and keep
456 * circling through all other CPUs when an error has been
457 * encountered.
458 */
459 for_each_possible_cpu(cpu) {
460 drvdata = per_cpu(debug_drvdata, cpu);
461 if (!drvdata)
462 continue;
463
464 ret = pm_runtime_put(drvdata->dev);
465 if (ret < 0)
466 err = ret;
467 }
468
469 return err;
470}
471
472static ssize_t debug_func_knob_write(struct file *f,
473 const char __user *buf, size_t count, loff_t *ppos)
474{
475 u8 val;
476 int ret;
477
478 ret = kstrtou8_from_user(buf, count, 2, &val);
479 if (ret)
480 return ret;
481
482 mutex_lock(&debug_lock);
483
484 if (val == debug_enable)
485 goto out;
486
487 if (val)
488 ret = debug_enable_func();
489 else
490 ret = debug_disable_func();
491
492 if (ret) {
493 pr_err("%s: unable to %s debug function: %d\n",
494 __func__, val ? "enable" : "disable", ret);
495 goto err;
496 }
497
498 debug_enable = val;
499out:
500 ret = count;
501err:
502 mutex_unlock(&debug_lock);
503 return ret;
504}
505
506static ssize_t debug_func_knob_read(struct file *f,
507 char __user *ubuf, size_t count, loff_t *ppos)
508{
509 ssize_t ret;
510 char buf[3];
511
512 mutex_lock(&debug_lock);
513 snprintf(buf, sizeof(buf), "%d\n", debug_enable);
514 mutex_unlock(&debug_lock);
515
516 ret = simple_read_from_buffer(ubuf, count, ppos, buf, sizeof(buf));
517 return ret;
518}
519
520static const struct file_operations debug_func_knob_fops = {
521 .open = simple_open,
522 .read = debug_func_knob_read,
523 .write = debug_func_knob_write,
524};
525
526static int debug_func_init(void)
527{
528 int ret;
529
530 /* Create debugfs node */
531 debug_debugfs_dir = debugfs_create_dir("coresight_cpu_debug", NULL);
532 debugfs_create_file("enable", 0644, debug_debugfs_dir, NULL,
533 &debug_func_knob_fops);
534
535 /* Register function to be called for panic */
536 ret = atomic_notifier_chain_register(&panic_notifier_list,
537 &debug_notifier);
538 if (ret) {
539 pr_err("%s: unable to register notifier: %d\n",
540 __func__, ret);
541 goto err;
542 }
543
544 return 0;
545
546err:
547 debugfs_remove_recursive(debug_debugfs_dir);
548 return ret;
549}
550
551static void debug_func_exit(void)
552{
553 atomic_notifier_chain_unregister(&panic_notifier_list,
554 &debug_notifier);
555 debugfs_remove_recursive(debug_debugfs_dir);
556}
557
558static int debug_probe(struct amba_device *adev, const struct amba_id *id)
559{
560 void __iomem *base;
561 struct device *dev = &adev->dev;
562 struct debug_drvdata *drvdata;
563 struct resource *res = &adev->res;
564 int ret;
565
566 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
567 if (!drvdata)
568 return -ENOMEM;
569
570 drvdata->cpu = coresight_get_cpu(dev);
571 if (drvdata->cpu < 0)
572 return drvdata->cpu;
573
574 if (per_cpu(debug_drvdata, drvdata->cpu)) {
575 dev_err(dev, "CPU%d drvdata has already been initialized\n",
576 drvdata->cpu);
577 return -EBUSY;
578 }
579
580 drvdata->dev = &adev->dev;
581 amba_set_drvdata(adev, drvdata);
582
583 /* Validity for the resource is already checked by the AMBA core */
584 base = devm_ioremap_resource(dev, res);
585 if (IS_ERR(base))
586 return PTR_ERR(base);
587
588 drvdata->base = base;
589
590 get_online_cpus();
591 per_cpu(debug_drvdata, drvdata->cpu) = drvdata;
592 ret = smp_call_function_single(drvdata->cpu, debug_init_arch_data,
593 drvdata, 1);
594 put_online_cpus();
595
596 if (ret) {
597 dev_err(dev, "CPU%d debug arch init failed\n", drvdata->cpu);
598 goto err;
599 }
600
601 if (!drvdata->edpcsr_present) {
602 dev_err(dev, "CPU%d sample-based profiling isn't implemented\n",
603 drvdata->cpu);
604 ret = -ENXIO;
605 goto err;
606 }
607
608 if (!debug_count++) {
609 ret = debug_func_init();
610 if (ret)
611 goto err_func_init;
612 }
613
614 mutex_lock(&debug_lock);
615 /* Turn off debug power domain if debugging is disabled */
616 if (!debug_enable)
617 pm_runtime_put(dev);
618 mutex_unlock(&debug_lock);
619
620 dev_info(dev, "Coresight debug-CPU%d initialized\n", drvdata->cpu);
621 return 0;
622
623err_func_init:
624 debug_count--;
625err:
626 per_cpu(debug_drvdata, drvdata->cpu) = NULL;
627 return ret;
628}
629
630static int debug_remove(struct amba_device *adev)
631{
632 struct device *dev = &adev->dev;
633 struct debug_drvdata *drvdata = amba_get_drvdata(adev);
634
635 per_cpu(debug_drvdata, drvdata->cpu) = NULL;
636
637 mutex_lock(&debug_lock);
638 /* Turn off debug power domain before rmmod the module */
639 if (debug_enable)
640 pm_runtime_put(dev);
641 mutex_unlock(&debug_lock);
642
643 if (!--debug_count)
644 debug_func_exit();
645
646 return 0;
647}
648
649static const struct amba_cs_uci_id uci_id_debug[] = {
650 {
651 /* CPU Debug UCI data */
652 .devarch = 0x47706a15,
653 .devarch_mask = 0xfff0ffff,
654 .devtype = 0x00000015,
655 }
656};
657
658static const struct amba_id debug_ids[] = {
659 CS_AMBA_ID(0x000bbd03), /* Cortex-A53 */
660 CS_AMBA_ID(0x000bbd07), /* Cortex-A57 */
661 CS_AMBA_ID(0x000bbd08), /* Cortex-A72 */
662 CS_AMBA_ID(0x000bbd09), /* Cortex-A73 */
663 CS_AMBA_UCI_ID(0x000f0205, uci_id_debug), /* Qualcomm Kryo */
664 CS_AMBA_UCI_ID(0x000f0211, uci_id_debug), /* Qualcomm Kryo */
665 {},
666};
667
668static struct amba_driver debug_driver = {
669 .drv = {
670 .name = "coresight-cpu-debug",
671 .suppress_bind_attrs = true,
672 },
673 .probe = debug_probe,
674 .remove = debug_remove,
675 .id_table = debug_ids,
676};
677
678module_amba_driver(debug_driver);
679
680MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
681MODULE_DESCRIPTION("ARM Coresight CPU Debug Driver");
682MODULE_LICENSE("GPL");