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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Octeon Watchdog driver
4 *
5 * Copyright (C) 2007-2017 Cavium, Inc.
6 *
7 * Converted to use WATCHDOG_CORE by Aaro Koskinen <aaro.koskinen@iki.fi>.
8 *
9 * Some parts derived from wdt.c
10 *
11 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
12 * All Rights Reserved.
13 *
14 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
15 * warranty for any of this software. This material is provided
16 * "AS-IS" and at no charge.
17 *
18 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
19 *
20 * The OCTEON watchdog has a maximum timeout of 2^32 * io_clock.
21 * For most systems this is less than 10 seconds, so to allow for
22 * software to request longer watchdog heartbeats, we maintain software
23 * counters to count multiples of the base rate. If the system locks
24 * up in such a manner that we can not run the software counters, the
25 * only result is a watchdog reset sooner than was requested. But
26 * that is OK, because in this case userspace would likely not be able
27 * to do anything anyhow.
28 *
29 * The hardware watchdog interval we call the period. The OCTEON
30 * watchdog goes through several stages, after the first period an
31 * irq is asserted, then if it is not reset, after the next period NMI
32 * is asserted, then after an additional period a chip wide soft reset.
33 * So for the software counters, we reset watchdog after each period
34 * and decrement the counter. But for the last two periods we need to
35 * let the watchdog progress to the NMI stage so we disable the irq
36 * and let it proceed. Once in the NMI, we print the register state
37 * to the serial port and then wait for the reset.
38 *
39 * A watchdog is maintained for each CPU in the system, that way if
40 * one CPU suffers a lockup, we also get a register dump and reset.
41 * The userspace ping resets the watchdog on all CPUs.
42 *
43 * Before userspace opens the watchdog device, we still run the
44 * watchdogs to catch any lockups that may be kernel related.
45 *
46 */
47
48#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
49
50#include <linux/interrupt.h>
51#include <linux/watchdog.h>
52#include <linux/cpumask.h>
53#include <linux/module.h>
54#include <linux/delay.h>
55#include <linux/cpu.h>
56#include <linux/irq.h>
57
58#include <asm/mipsregs.h>
59#include <asm/uasm.h>
60
61#include <asm/octeon/octeon.h>
62#include <asm/octeon/cvmx-boot-vector.h>
63#include <asm/octeon/cvmx-ciu2-defs.h>
64#include <asm/octeon/cvmx-rst-defs.h>
65
66/* Watchdog interrupt major block number (8 MSBs of intsn) */
67#define WD_BLOCK_NUMBER 0x01
68
69static int divisor;
70
71/* The count needed to achieve timeout_sec. */
72static unsigned int timeout_cnt;
73
74/* The maximum period supported. */
75static unsigned int max_timeout_sec;
76
77/* The current period. */
78static unsigned int timeout_sec;
79
80/* Set to non-zero when userspace countdown mode active */
81static bool do_countdown;
82static unsigned int countdown_reset;
83static unsigned int per_cpu_countdown[NR_CPUS];
84
85static cpumask_t irq_enabled_cpus;
86
87#define WD_TIMO 60 /* Default heartbeat = 60 seconds */
88
89#define CVMX_GSERX_SCRATCH(offset) (CVMX_ADD_IO_SEG(0x0001180090000020ull) + ((offset) & 15) * 0x1000000ull)
90
91static int heartbeat = WD_TIMO;
92module_param(heartbeat, int, 0444);
93MODULE_PARM_DESC(heartbeat,
94 "Watchdog heartbeat in seconds. (0 < heartbeat, default="
95 __MODULE_STRING(WD_TIMO) ")");
96
97static bool nowayout = WATCHDOG_NOWAYOUT;
98module_param(nowayout, bool, 0444);
99MODULE_PARM_DESC(nowayout,
100 "Watchdog cannot be stopped once started (default="
101 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
102
103static int disable;
104module_param(disable, int, 0444);
105MODULE_PARM_DESC(disable,
106 "Disable the watchdog entirely (default=0)");
107
108static struct cvmx_boot_vector_element *octeon_wdt_bootvector;
109
110void octeon_wdt_nmi_stage2(void);
111
112static int cpu2core(int cpu)
113{
114#ifdef CONFIG_SMP
115 return cpu_logical_map(cpu) & 0x3f;
116#else
117 return cvmx_get_core_num();
118#endif
119}
120
121/**
122 * Poke the watchdog when an interrupt is received
123 *
124 * @cpl:
125 * @dev_id:
126 *
127 * Returns
128 */
129static irqreturn_t octeon_wdt_poke_irq(int cpl, void *dev_id)
130{
131 int cpu = raw_smp_processor_id();
132 unsigned int core = cpu2core(cpu);
133 int node = cpu_to_node(cpu);
134
135 if (do_countdown) {
136 if (per_cpu_countdown[cpu] > 0) {
137 /* We're alive, poke the watchdog */
138 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1);
139 per_cpu_countdown[cpu]--;
140 } else {
141 /* Bad news, you are about to reboot. */
142 disable_irq_nosync(cpl);
143 cpumask_clear_cpu(cpu, &irq_enabled_cpus);
144 }
145 } else {
146 /* Not open, just ping away... */
147 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1);
148 }
149 return IRQ_HANDLED;
150}
151
152/* From setup.c */
153extern int prom_putchar(char c);
154
155/**
156 * Write a string to the uart
157 *
158 * @str: String to write
159 */
160static void octeon_wdt_write_string(const char *str)
161{
162 /* Just loop writing one byte at a time */
163 while (*str)
164 prom_putchar(*str++);
165}
166
167/**
168 * Write a hex number out of the uart
169 *
170 * @value: Number to display
171 * @digits: Number of digits to print (1 to 16)
172 */
173static void octeon_wdt_write_hex(u64 value, int digits)
174{
175 int d;
176 int v;
177
178 for (d = 0; d < digits; d++) {
179 v = (value >> ((digits - d - 1) * 4)) & 0xf;
180 if (v >= 10)
181 prom_putchar('a' + v - 10);
182 else
183 prom_putchar('0' + v);
184 }
185}
186
187static const char reg_name[][3] = {
188 "$0", "at", "v0", "v1", "a0", "a1", "a2", "a3",
189 "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3",
190 "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7",
191 "t8", "t9", "k0", "k1", "gp", "sp", "s8", "ra"
192};
193
194/**
195 * NMI stage 3 handler. NMIs are handled in the following manner:
196 * 1) The first NMI handler enables CVMSEG and transfers from
197 * the bootbus region into normal memory. It is careful to not
198 * destroy any registers.
199 * 2) The second stage handler uses CVMSEG to save the registers
200 * and create a stack for C code. It then calls the third level
201 * handler with one argument, a pointer to the register values.
202 * 3) The third, and final, level handler is the following C
203 * function that prints out some useful infomration.
204 *
205 * @reg: Pointer to register state before the NMI
206 */
207void octeon_wdt_nmi_stage3(u64 reg[32])
208{
209 u64 i;
210
211 unsigned int coreid = cvmx_get_core_num();
212 /*
213 * Save status and cause early to get them before any changes
214 * might happen.
215 */
216 u64 cp0_cause = read_c0_cause();
217 u64 cp0_status = read_c0_status();
218 u64 cp0_error_epc = read_c0_errorepc();
219 u64 cp0_epc = read_c0_epc();
220
221 /* Delay so output from all cores output is not jumbled together. */
222 udelay(85000 * coreid);
223
224 octeon_wdt_write_string("\r\n*** NMI Watchdog interrupt on Core 0x");
225 octeon_wdt_write_hex(coreid, 2);
226 octeon_wdt_write_string(" ***\r\n");
227 for (i = 0; i < 32; i++) {
228 octeon_wdt_write_string("\t");
229 octeon_wdt_write_string(reg_name[i]);
230 octeon_wdt_write_string("\t0x");
231 octeon_wdt_write_hex(reg[i], 16);
232 if (i & 1)
233 octeon_wdt_write_string("\r\n");
234 }
235 octeon_wdt_write_string("\terr_epc\t0x");
236 octeon_wdt_write_hex(cp0_error_epc, 16);
237
238 octeon_wdt_write_string("\tepc\t0x");
239 octeon_wdt_write_hex(cp0_epc, 16);
240 octeon_wdt_write_string("\r\n");
241
242 octeon_wdt_write_string("\tstatus\t0x");
243 octeon_wdt_write_hex(cp0_status, 16);
244 octeon_wdt_write_string("\tcause\t0x");
245 octeon_wdt_write_hex(cp0_cause, 16);
246 octeon_wdt_write_string("\r\n");
247
248 /* The CIU register is different for each Octeon model. */
249 if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
250 octeon_wdt_write_string("\tsrc_wd\t0x");
251 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SRC_PPX_IP2_WDOG(coreid)), 16);
252 octeon_wdt_write_string("\ten_wd\t0x");
253 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_EN_PPX_IP2_WDOG(coreid)), 16);
254 octeon_wdt_write_string("\r\n");
255 octeon_wdt_write_string("\tsrc_rml\t0x");
256 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SRC_PPX_IP2_RML(coreid)), 16);
257 octeon_wdt_write_string("\ten_rml\t0x");
258 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_EN_PPX_IP2_RML(coreid)), 16);
259 octeon_wdt_write_string("\r\n");
260 octeon_wdt_write_string("\tsum\t0x");
261 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SUM_PPX_IP2(coreid)), 16);
262 octeon_wdt_write_string("\r\n");
263 } else if (!octeon_has_feature(OCTEON_FEATURE_CIU3)) {
264 octeon_wdt_write_string("\tsum0\t0x");
265 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_SUM0(coreid * 2)), 16);
266 octeon_wdt_write_string("\ten0\t0x");
267 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_EN0(coreid * 2)), 16);
268 octeon_wdt_write_string("\r\n");
269 }
270
271 octeon_wdt_write_string("*** Chip soft reset soon ***\r\n");
272
273 /*
274 * G-30204: We must trigger a soft reset before watchdog
275 * does an incomplete job of doing it.
276 */
277 if (OCTEON_IS_OCTEON3() && !OCTEON_IS_MODEL(OCTEON_CN70XX)) {
278 u64 scr;
279 unsigned int node = cvmx_get_node_num();
280 unsigned int lcore = cvmx_get_local_core_num();
281 union cvmx_ciu_wdogx ciu_wdog;
282
283 /*
284 * Wait for other cores to print out information, but
285 * not too long. Do the soft reset before watchdog
286 * can trigger it.
287 */
288 do {
289 ciu_wdog.u64 = cvmx_read_csr_node(node, CVMX_CIU_WDOGX(lcore));
290 } while (ciu_wdog.s.cnt > 0x10000);
291
292 scr = cvmx_read_csr_node(0, CVMX_GSERX_SCRATCH(0));
293 scr |= 1 << 11; /* Indicate watchdog in bit 11 */
294 cvmx_write_csr_node(0, CVMX_GSERX_SCRATCH(0), scr);
295 cvmx_write_csr_node(0, CVMX_RST_SOFT_RST, 1);
296 }
297}
298
299static int octeon_wdt_cpu_to_irq(int cpu)
300{
301 unsigned int coreid;
302 int node;
303 int irq;
304
305 coreid = cpu2core(cpu);
306 node = cpu_to_node(cpu);
307
308 if (octeon_has_feature(OCTEON_FEATURE_CIU3)) {
309 struct irq_domain *domain;
310 int hwirq;
311
312 domain = octeon_irq_get_block_domain(node,
313 WD_BLOCK_NUMBER);
314 hwirq = WD_BLOCK_NUMBER << 12 | 0x200 | coreid;
315 irq = irq_find_mapping(domain, hwirq);
316 } else {
317 irq = OCTEON_IRQ_WDOG0 + coreid;
318 }
319 return irq;
320}
321
322static int octeon_wdt_cpu_pre_down(unsigned int cpu)
323{
324 unsigned int core;
325 int node;
326 union cvmx_ciu_wdogx ciu_wdog;
327
328 core = cpu2core(cpu);
329
330 node = cpu_to_node(cpu);
331
332 /* Poke the watchdog to clear out its state */
333 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1);
334
335 /* Disable the hardware. */
336 ciu_wdog.u64 = 0;
337 cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64);
338
339 free_irq(octeon_wdt_cpu_to_irq(cpu), octeon_wdt_poke_irq);
340 return 0;
341}
342
343static int octeon_wdt_cpu_online(unsigned int cpu)
344{
345 unsigned int core;
346 unsigned int irq;
347 union cvmx_ciu_wdogx ciu_wdog;
348 int node;
349 struct irq_domain *domain;
350 int hwirq;
351
352 core = cpu2core(cpu);
353 node = cpu_to_node(cpu);
354
355 octeon_wdt_bootvector[core].target_ptr = (u64)octeon_wdt_nmi_stage2;
356
357 /* Disable it before doing anything with the interrupts. */
358 ciu_wdog.u64 = 0;
359 cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64);
360
361 per_cpu_countdown[cpu] = countdown_reset;
362
363 if (octeon_has_feature(OCTEON_FEATURE_CIU3)) {
364 /* Must get the domain for the watchdog block */
365 domain = octeon_irq_get_block_domain(node, WD_BLOCK_NUMBER);
366
367 /* Get a irq for the wd intsn (hardware interrupt) */
368 hwirq = WD_BLOCK_NUMBER << 12 | 0x200 | core;
369 irq = irq_create_mapping(domain, hwirq);
370 irqd_set_trigger_type(irq_get_irq_data(irq),
371 IRQ_TYPE_EDGE_RISING);
372 } else
373 irq = OCTEON_IRQ_WDOG0 + core;
374
375 if (request_irq(irq, octeon_wdt_poke_irq,
376 IRQF_NO_THREAD, "octeon_wdt", octeon_wdt_poke_irq))
377 panic("octeon_wdt: Couldn't obtain irq %d", irq);
378
379 /* Must set the irq affinity here */
380 if (octeon_has_feature(OCTEON_FEATURE_CIU3)) {
381 cpumask_t mask;
382
383 cpumask_clear(&mask);
384 cpumask_set_cpu(cpu, &mask);
385 irq_set_affinity(irq, &mask);
386 }
387
388 cpumask_set_cpu(cpu, &irq_enabled_cpus);
389
390 /* Poke the watchdog to clear out its state */
391 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1);
392
393 /* Finally enable the watchdog now that all handlers are installed */
394 ciu_wdog.u64 = 0;
395 ciu_wdog.s.len = timeout_cnt;
396 ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
397 cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64);
398
399 return 0;
400}
401
402static int octeon_wdt_ping(struct watchdog_device __always_unused *wdog)
403{
404 int cpu;
405 int coreid;
406 int node;
407
408 if (disable)
409 return 0;
410
411 for_each_online_cpu(cpu) {
412 coreid = cpu2core(cpu);
413 node = cpu_to_node(cpu);
414 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1);
415 per_cpu_countdown[cpu] = countdown_reset;
416 if ((countdown_reset || !do_countdown) &&
417 !cpumask_test_cpu(cpu, &irq_enabled_cpus)) {
418 /* We have to enable the irq */
419 enable_irq(octeon_wdt_cpu_to_irq(cpu));
420 cpumask_set_cpu(cpu, &irq_enabled_cpus);
421 }
422 }
423 return 0;
424}
425
426static void octeon_wdt_calc_parameters(int t)
427{
428 unsigned int periods;
429
430 timeout_sec = max_timeout_sec;
431
432
433 /*
434 * Find the largest interrupt period, that can evenly divide
435 * the requested heartbeat time.
436 */
437 while ((t % timeout_sec) != 0)
438 timeout_sec--;
439
440 periods = t / timeout_sec;
441
442 /*
443 * The last two periods are after the irq is disabled, and
444 * then to the nmi, so we subtract them off.
445 */
446
447 countdown_reset = periods > 2 ? periods - 2 : 0;
448 heartbeat = t;
449 timeout_cnt = ((octeon_get_io_clock_rate() / divisor) * timeout_sec) >> 8;
450}
451
452static int octeon_wdt_set_timeout(struct watchdog_device *wdog,
453 unsigned int t)
454{
455 int cpu;
456 int coreid;
457 union cvmx_ciu_wdogx ciu_wdog;
458 int node;
459
460 if (t <= 0)
461 return -1;
462
463 octeon_wdt_calc_parameters(t);
464
465 if (disable)
466 return 0;
467
468 for_each_online_cpu(cpu) {
469 coreid = cpu2core(cpu);
470 node = cpu_to_node(cpu);
471 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1);
472 ciu_wdog.u64 = 0;
473 ciu_wdog.s.len = timeout_cnt;
474 ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
475 cvmx_write_csr_node(node, CVMX_CIU_WDOGX(coreid), ciu_wdog.u64);
476 cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1);
477 }
478 octeon_wdt_ping(wdog); /* Get the irqs back on. */
479 return 0;
480}
481
482static int octeon_wdt_start(struct watchdog_device *wdog)
483{
484 octeon_wdt_ping(wdog);
485 do_countdown = 1;
486 return 0;
487}
488
489static int octeon_wdt_stop(struct watchdog_device *wdog)
490{
491 do_countdown = 0;
492 octeon_wdt_ping(wdog);
493 return 0;
494}
495
496static const struct watchdog_info octeon_wdt_info = {
497 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
498 .identity = "OCTEON",
499};
500
501static const struct watchdog_ops octeon_wdt_ops = {
502 .owner = THIS_MODULE,
503 .start = octeon_wdt_start,
504 .stop = octeon_wdt_stop,
505 .ping = octeon_wdt_ping,
506 .set_timeout = octeon_wdt_set_timeout,
507};
508
509static struct watchdog_device octeon_wdt = {
510 .info = &octeon_wdt_info,
511 .ops = &octeon_wdt_ops,
512};
513
514static enum cpuhp_state octeon_wdt_online;
515/**
516 * Module/ driver initialization.
517 *
518 * Returns Zero on success
519 */
520static int __init octeon_wdt_init(void)
521{
522 int ret;
523
524 octeon_wdt_bootvector = cvmx_boot_vector_get();
525 if (!octeon_wdt_bootvector) {
526 pr_err("Error: Cannot allocate boot vector.\n");
527 return -ENOMEM;
528 }
529
530 if (OCTEON_IS_MODEL(OCTEON_CN68XX))
531 divisor = 0x200;
532 else if (OCTEON_IS_MODEL(OCTEON_CN78XX))
533 divisor = 0x400;
534 else
535 divisor = 0x100;
536
537 /*
538 * Watchdog time expiration length = The 16 bits of LEN
539 * represent the most significant bits of a 24 bit decrementer
540 * that decrements every divisor cycle.
541 *
542 * Try for a timeout of 5 sec, if that fails a smaller number
543 * of even seconds,
544 */
545 max_timeout_sec = 6;
546 do {
547 max_timeout_sec--;
548 timeout_cnt = ((octeon_get_io_clock_rate() / divisor) * max_timeout_sec) >> 8;
549 } while (timeout_cnt > 65535);
550
551 BUG_ON(timeout_cnt == 0);
552
553 octeon_wdt_calc_parameters(heartbeat);
554
555 pr_info("Initial granularity %d Sec\n", timeout_sec);
556
557 octeon_wdt.timeout = timeout_sec;
558 octeon_wdt.max_timeout = UINT_MAX;
559
560 watchdog_set_nowayout(&octeon_wdt, nowayout);
561
562 ret = watchdog_register_device(&octeon_wdt);
563 if (ret) {
564 pr_err("watchdog_register_device() failed: %d\n", ret);
565 return ret;
566 }
567
568 if (disable) {
569 pr_notice("disabled\n");
570 return 0;
571 }
572
573 cpumask_clear(&irq_enabled_cpus);
574
575 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "watchdog/octeon:online",
576 octeon_wdt_cpu_online, octeon_wdt_cpu_pre_down);
577 if (ret < 0)
578 goto err;
579 octeon_wdt_online = ret;
580 return 0;
581err:
582 cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0);
583 watchdog_unregister_device(&octeon_wdt);
584 return ret;
585}
586
587/**
588 * Module / driver shutdown
589 */
590static void __exit octeon_wdt_cleanup(void)
591{
592 watchdog_unregister_device(&octeon_wdt);
593
594 if (disable)
595 return;
596
597 cpuhp_remove_state(octeon_wdt_online);
598
599 /*
600 * Disable the boot-bus memory, the code it points to is soon
601 * to go missing.
602 */
603 cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0);
604}
605
606MODULE_LICENSE("GPL");
607MODULE_AUTHOR("Cavium Inc. <support@cavium.com>");
608MODULE_DESCRIPTION("Cavium Inc. OCTEON Watchdog driver.");
609module_init(octeon_wdt_init);
610module_exit(octeon_wdt_cleanup);
1/*
2 * Octeon Watchdog driver
3 *
4 * Copyright (C) 2007, 2008, 2009, 2010 Cavium Networks
5 *
6 * Converted to use WATCHDOG_CORE by Aaro Koskinen <aaro.koskinen@iki.fi>.
7 *
8 * Some parts derived from wdt.c
9 *
10 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11 * All Rights Reserved.
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 *
18 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
19 * warranty for any of this software. This material is provided
20 * "AS-IS" and at no charge.
21 *
22 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
23 *
24 * This file is subject to the terms and conditions of the GNU General Public
25 * License. See the file "COPYING" in the main directory of this archive
26 * for more details.
27 *
28 *
29 * The OCTEON watchdog has a maximum timeout of 2^32 * io_clock.
30 * For most systems this is less than 10 seconds, so to allow for
31 * software to request longer watchdog heartbeats, we maintain software
32 * counters to count multiples of the base rate. If the system locks
33 * up in such a manner that we can not run the software counters, the
34 * only result is a watchdog reset sooner than was requested. But
35 * that is OK, because in this case userspace would likely not be able
36 * to do anything anyhow.
37 *
38 * The hardware watchdog interval we call the period. The OCTEON
39 * watchdog goes through several stages, after the first period an
40 * irq is asserted, then if it is not reset, after the next period NMI
41 * is asserted, then after an additional period a chip wide soft reset.
42 * So for the software counters, we reset watchdog after each period
43 * and decrement the counter. But for the last two periods we need to
44 * let the watchdog progress to the NMI stage so we disable the irq
45 * and let it proceed. Once in the NMI, we print the register state
46 * to the serial port and then wait for the reset.
47 *
48 * A watchdog is maintained for each CPU in the system, that way if
49 * one CPU suffers a lockup, we also get a register dump and reset.
50 * The userspace ping resets the watchdog on all CPUs.
51 *
52 * Before userspace opens the watchdog device, we still run the
53 * watchdogs to catch any lockups that may be kernel related.
54 *
55 */
56
57#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
58
59#include <linux/miscdevice.h>
60#include <linux/interrupt.h>
61#include <linux/watchdog.h>
62#include <linux/cpumask.h>
63#include <linux/bitops.h>
64#include <linux/kernel.h>
65#include <linux/module.h>
66#include <linux/string.h>
67#include <linux/delay.h>
68#include <linux/cpu.h>
69#include <linux/smp.h>
70#include <linux/fs.h>
71#include <linux/irq.h>
72
73#include <asm/mipsregs.h>
74#include <asm/uasm.h>
75
76#include <asm/octeon/octeon.h>
77
78/* The count needed to achieve timeout_sec. */
79static unsigned int timeout_cnt;
80
81/* The maximum period supported. */
82static unsigned int max_timeout_sec;
83
84/* The current period. */
85static unsigned int timeout_sec;
86
87/* Set to non-zero when userspace countdown mode active */
88static int do_coundown;
89static unsigned int countdown_reset;
90static unsigned int per_cpu_countdown[NR_CPUS];
91
92static cpumask_t irq_enabled_cpus;
93
94#define WD_TIMO 60 /* Default heartbeat = 60 seconds */
95
96static int heartbeat = WD_TIMO;
97module_param(heartbeat, int, S_IRUGO);
98MODULE_PARM_DESC(heartbeat,
99 "Watchdog heartbeat in seconds. (0 < heartbeat, default="
100 __MODULE_STRING(WD_TIMO) ")");
101
102static bool nowayout = WATCHDOG_NOWAYOUT;
103module_param(nowayout, bool, S_IRUGO);
104MODULE_PARM_DESC(nowayout,
105 "Watchdog cannot be stopped once started (default="
106 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
107
108static u32 nmi_stage1_insns[64] __initdata;
109/* We need one branch and therefore one relocation per target label. */
110static struct uasm_label labels[5] __initdata;
111static struct uasm_reloc relocs[5] __initdata;
112
113enum lable_id {
114 label_enter_bootloader = 1
115};
116
117/* Some CP0 registers */
118#define K0 26
119#define C0_CVMMEMCTL 11, 7
120#define C0_STATUS 12, 0
121#define C0_EBASE 15, 1
122#define C0_DESAVE 31, 0
123
124void octeon_wdt_nmi_stage2(void);
125
126static void __init octeon_wdt_build_stage1(void)
127{
128 int i;
129 int len;
130 u32 *p = nmi_stage1_insns;
131#ifdef CONFIG_HOTPLUG_CPU
132 struct uasm_label *l = labels;
133 struct uasm_reloc *r = relocs;
134#endif
135
136 /*
137 * For the next few instructions running the debugger may
138 * cause corruption of k0 in the saved registers. Since we're
139 * about to crash, nobody probably cares.
140 *
141 * Save K0 into the debug scratch register
142 */
143 uasm_i_dmtc0(&p, K0, C0_DESAVE);
144
145 uasm_i_mfc0(&p, K0, C0_STATUS);
146#ifdef CONFIG_HOTPLUG_CPU
147 if (octeon_bootloader_entry_addr)
148 uasm_il_bbit0(&p, &r, K0, ilog2(ST0_NMI),
149 label_enter_bootloader);
150#endif
151 /* Force 64-bit addressing enabled */
152 uasm_i_ori(&p, K0, K0, ST0_UX | ST0_SX | ST0_KX);
153 uasm_i_mtc0(&p, K0, C0_STATUS);
154
155#ifdef CONFIG_HOTPLUG_CPU
156 if (octeon_bootloader_entry_addr) {
157 uasm_i_mfc0(&p, K0, C0_EBASE);
158 /* Coreid number in K0 */
159 uasm_i_andi(&p, K0, K0, 0xf);
160 /* 8 * coreid in bits 16-31 */
161 uasm_i_dsll_safe(&p, K0, K0, 3 + 16);
162 uasm_i_ori(&p, K0, K0, 0x8001);
163 uasm_i_dsll_safe(&p, K0, K0, 16);
164 uasm_i_ori(&p, K0, K0, 0x0700);
165 uasm_i_drotr_safe(&p, K0, K0, 32);
166 /*
167 * Should result in: 0x8001,0700,0000,8*coreid which is
168 * CVMX_CIU_WDOGX(coreid) - 0x0500
169 *
170 * Now ld K0, CVMX_CIU_WDOGX(coreid)
171 */
172 uasm_i_ld(&p, K0, 0x500, K0);
173 /*
174 * If bit one set handle the NMI as a watchdog event.
175 * otherwise transfer control to bootloader.
176 */
177 uasm_il_bbit0(&p, &r, K0, 1, label_enter_bootloader);
178 uasm_i_nop(&p);
179 }
180#endif
181
182 /* Clear Dcache so cvmseg works right. */
183 uasm_i_cache(&p, 1, 0, 0);
184
185 /* Use K0 to do a read/modify/write of CVMMEMCTL */
186 uasm_i_dmfc0(&p, K0, C0_CVMMEMCTL);
187 /* Clear out the size of CVMSEG */
188 uasm_i_dins(&p, K0, 0, 0, 6);
189 /* Set CVMSEG to its largest value */
190 uasm_i_ori(&p, K0, K0, 0x1c0 | 54);
191 /* Store the CVMMEMCTL value */
192 uasm_i_dmtc0(&p, K0, C0_CVMMEMCTL);
193
194 /* Load the address of the second stage handler */
195 UASM_i_LA(&p, K0, (long)octeon_wdt_nmi_stage2);
196 uasm_i_jr(&p, K0);
197 uasm_i_dmfc0(&p, K0, C0_DESAVE);
198
199#ifdef CONFIG_HOTPLUG_CPU
200 if (octeon_bootloader_entry_addr) {
201 uasm_build_label(&l, p, label_enter_bootloader);
202 /* Jump to the bootloader and restore K0 */
203 UASM_i_LA(&p, K0, (long)octeon_bootloader_entry_addr);
204 uasm_i_jr(&p, K0);
205 uasm_i_dmfc0(&p, K0, C0_DESAVE);
206 }
207#endif
208 uasm_resolve_relocs(relocs, labels);
209
210 len = (int)(p - nmi_stage1_insns);
211 pr_debug("Synthesized NMI stage 1 handler (%d instructions)\n", len);
212
213 pr_debug("\t.set push\n");
214 pr_debug("\t.set noreorder\n");
215 for (i = 0; i < len; i++)
216 pr_debug("\t.word 0x%08x\n", nmi_stage1_insns[i]);
217 pr_debug("\t.set pop\n");
218
219 if (len > 32)
220 panic("NMI stage 1 handler exceeds 32 instructions, was %d\n",
221 len);
222}
223
224static int cpu2core(int cpu)
225{
226#ifdef CONFIG_SMP
227 return cpu_logical_map(cpu);
228#else
229 return cvmx_get_core_num();
230#endif
231}
232
233static int core2cpu(int coreid)
234{
235#ifdef CONFIG_SMP
236 return cpu_number_map(coreid);
237#else
238 return 0;
239#endif
240}
241
242/**
243 * Poke the watchdog when an interrupt is received
244 *
245 * @cpl:
246 * @dev_id:
247 *
248 * Returns
249 */
250static irqreturn_t octeon_wdt_poke_irq(int cpl, void *dev_id)
251{
252 unsigned int core = cvmx_get_core_num();
253 int cpu = core2cpu(core);
254
255 if (do_coundown) {
256 if (per_cpu_countdown[cpu] > 0) {
257 /* We're alive, poke the watchdog */
258 cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
259 per_cpu_countdown[cpu]--;
260 } else {
261 /* Bad news, you are about to reboot. */
262 disable_irq_nosync(cpl);
263 cpumask_clear_cpu(cpu, &irq_enabled_cpus);
264 }
265 } else {
266 /* Not open, just ping away... */
267 cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
268 }
269 return IRQ_HANDLED;
270}
271
272/* From setup.c */
273extern int prom_putchar(char c);
274
275/**
276 * Write a string to the uart
277 *
278 * @str: String to write
279 */
280static void octeon_wdt_write_string(const char *str)
281{
282 /* Just loop writing one byte at a time */
283 while (*str)
284 prom_putchar(*str++);
285}
286
287/**
288 * Write a hex number out of the uart
289 *
290 * @value: Number to display
291 * @digits: Number of digits to print (1 to 16)
292 */
293static void octeon_wdt_write_hex(u64 value, int digits)
294{
295 int d;
296 int v;
297
298 for (d = 0; d < digits; d++) {
299 v = (value >> ((digits - d - 1) * 4)) & 0xf;
300 if (v >= 10)
301 prom_putchar('a' + v - 10);
302 else
303 prom_putchar('0' + v);
304 }
305}
306
307static const char reg_name[][3] = {
308 "$0", "at", "v0", "v1", "a0", "a1", "a2", "a3",
309 "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3",
310 "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7",
311 "t8", "t9", "k0", "k1", "gp", "sp", "s8", "ra"
312};
313
314/**
315 * NMI stage 3 handler. NMIs are handled in the following manner:
316 * 1) The first NMI handler enables CVMSEG and transfers from
317 * the bootbus region into normal memory. It is careful to not
318 * destroy any registers.
319 * 2) The second stage handler uses CVMSEG to save the registers
320 * and create a stack for C code. It then calls the third level
321 * handler with one argument, a pointer to the register values.
322 * 3) The third, and final, level handler is the following C
323 * function that prints out some useful infomration.
324 *
325 * @reg: Pointer to register state before the NMI
326 */
327void octeon_wdt_nmi_stage3(u64 reg[32])
328{
329 u64 i;
330
331 unsigned int coreid = cvmx_get_core_num();
332 /*
333 * Save status and cause early to get them before any changes
334 * might happen.
335 */
336 u64 cp0_cause = read_c0_cause();
337 u64 cp0_status = read_c0_status();
338 u64 cp0_error_epc = read_c0_errorepc();
339 u64 cp0_epc = read_c0_epc();
340
341 /* Delay so output from all cores output is not jumbled together. */
342 __delay(100000000ull * coreid);
343
344 octeon_wdt_write_string("\r\n*** NMI Watchdog interrupt on Core 0x");
345 octeon_wdt_write_hex(coreid, 1);
346 octeon_wdt_write_string(" ***\r\n");
347 for (i = 0; i < 32; i++) {
348 octeon_wdt_write_string("\t");
349 octeon_wdt_write_string(reg_name[i]);
350 octeon_wdt_write_string("\t0x");
351 octeon_wdt_write_hex(reg[i], 16);
352 if (i & 1)
353 octeon_wdt_write_string("\r\n");
354 }
355 octeon_wdt_write_string("\terr_epc\t0x");
356 octeon_wdt_write_hex(cp0_error_epc, 16);
357
358 octeon_wdt_write_string("\tepc\t0x");
359 octeon_wdt_write_hex(cp0_epc, 16);
360 octeon_wdt_write_string("\r\n");
361
362 octeon_wdt_write_string("\tstatus\t0x");
363 octeon_wdt_write_hex(cp0_status, 16);
364 octeon_wdt_write_string("\tcause\t0x");
365 octeon_wdt_write_hex(cp0_cause, 16);
366 octeon_wdt_write_string("\r\n");
367
368 octeon_wdt_write_string("\tsum0\t0x");
369 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_SUM0(coreid * 2)), 16);
370 octeon_wdt_write_string("\ten0\t0x");
371 octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_EN0(coreid * 2)), 16);
372 octeon_wdt_write_string("\r\n");
373
374 octeon_wdt_write_string("*** Chip soft reset soon ***\r\n");
375}
376
377static void octeon_wdt_disable_interrupt(int cpu)
378{
379 unsigned int core;
380 unsigned int irq;
381 union cvmx_ciu_wdogx ciu_wdog;
382
383 core = cpu2core(cpu);
384
385 irq = OCTEON_IRQ_WDOG0 + core;
386
387 /* Poke the watchdog to clear out its state */
388 cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
389
390 /* Disable the hardware. */
391 ciu_wdog.u64 = 0;
392 cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
393
394 free_irq(irq, octeon_wdt_poke_irq);
395}
396
397static void octeon_wdt_setup_interrupt(int cpu)
398{
399 unsigned int core;
400 unsigned int irq;
401 union cvmx_ciu_wdogx ciu_wdog;
402
403 core = cpu2core(cpu);
404
405 /* Disable it before doing anything with the interrupts. */
406 ciu_wdog.u64 = 0;
407 cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
408
409 per_cpu_countdown[cpu] = countdown_reset;
410
411 irq = OCTEON_IRQ_WDOG0 + core;
412
413 if (request_irq(irq, octeon_wdt_poke_irq,
414 IRQF_NO_THREAD, "octeon_wdt", octeon_wdt_poke_irq))
415 panic("octeon_wdt: Couldn't obtain irq %d", irq);
416
417 cpumask_set_cpu(cpu, &irq_enabled_cpus);
418
419 /* Poke the watchdog to clear out its state */
420 cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
421
422 /* Finally enable the watchdog now that all handlers are installed */
423 ciu_wdog.u64 = 0;
424 ciu_wdog.s.len = timeout_cnt;
425 ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
426 cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
427}
428
429static int octeon_wdt_cpu_callback(struct notifier_block *nfb,
430 unsigned long action, void *hcpu)
431{
432 unsigned int cpu = (unsigned long)hcpu;
433
434 switch (action) {
435 case CPU_DOWN_PREPARE:
436 octeon_wdt_disable_interrupt(cpu);
437 break;
438 case CPU_ONLINE:
439 case CPU_DOWN_FAILED:
440 octeon_wdt_setup_interrupt(cpu);
441 break;
442 default:
443 break;
444 }
445 return NOTIFY_OK;
446}
447
448static int octeon_wdt_ping(struct watchdog_device __always_unused *wdog)
449{
450 int cpu;
451 int coreid;
452
453 for_each_online_cpu(cpu) {
454 coreid = cpu2core(cpu);
455 cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
456 per_cpu_countdown[cpu] = countdown_reset;
457 if ((countdown_reset || !do_coundown) &&
458 !cpumask_test_cpu(cpu, &irq_enabled_cpus)) {
459 /* We have to enable the irq */
460 int irq = OCTEON_IRQ_WDOG0 + coreid;
461
462 enable_irq(irq);
463 cpumask_set_cpu(cpu, &irq_enabled_cpus);
464 }
465 }
466 return 0;
467}
468
469static void octeon_wdt_calc_parameters(int t)
470{
471 unsigned int periods;
472
473 timeout_sec = max_timeout_sec;
474
475
476 /*
477 * Find the largest interrupt period, that can evenly divide
478 * the requested heartbeat time.
479 */
480 while ((t % timeout_sec) != 0)
481 timeout_sec--;
482
483 periods = t / timeout_sec;
484
485 /*
486 * The last two periods are after the irq is disabled, and
487 * then to the nmi, so we subtract them off.
488 */
489
490 countdown_reset = periods > 2 ? periods - 2 : 0;
491 heartbeat = t;
492 timeout_cnt = ((octeon_get_io_clock_rate() >> 8) * timeout_sec) >> 8;
493}
494
495static int octeon_wdt_set_timeout(struct watchdog_device *wdog,
496 unsigned int t)
497{
498 int cpu;
499 int coreid;
500 union cvmx_ciu_wdogx ciu_wdog;
501
502 if (t <= 0)
503 return -1;
504
505 octeon_wdt_calc_parameters(t);
506
507 for_each_online_cpu(cpu) {
508 coreid = cpu2core(cpu);
509 cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
510 ciu_wdog.u64 = 0;
511 ciu_wdog.s.len = timeout_cnt;
512 ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
513 cvmx_write_csr(CVMX_CIU_WDOGX(coreid), ciu_wdog.u64);
514 cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
515 }
516 octeon_wdt_ping(wdog); /* Get the irqs back on. */
517 return 0;
518}
519
520static int octeon_wdt_start(struct watchdog_device *wdog)
521{
522 octeon_wdt_ping(wdog);
523 do_coundown = 1;
524 return 0;
525}
526
527static int octeon_wdt_stop(struct watchdog_device *wdog)
528{
529 do_coundown = 0;
530 octeon_wdt_ping(wdog);
531 return 0;
532}
533
534static struct notifier_block octeon_wdt_cpu_notifier = {
535 .notifier_call = octeon_wdt_cpu_callback,
536};
537
538static const struct watchdog_info octeon_wdt_info = {
539 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
540 .identity = "OCTEON",
541};
542
543static const struct watchdog_ops octeon_wdt_ops = {
544 .owner = THIS_MODULE,
545 .start = octeon_wdt_start,
546 .stop = octeon_wdt_stop,
547 .ping = octeon_wdt_ping,
548 .set_timeout = octeon_wdt_set_timeout,
549};
550
551static struct watchdog_device octeon_wdt = {
552 .info = &octeon_wdt_info,
553 .ops = &octeon_wdt_ops,
554};
555
556/**
557 * Module/ driver initialization.
558 *
559 * Returns Zero on success
560 */
561static int __init octeon_wdt_init(void)
562{
563 int i;
564 int ret;
565 int cpu;
566 u64 *ptr;
567
568 /*
569 * Watchdog time expiration length = The 16 bits of LEN
570 * represent the most significant bits of a 24 bit decrementer
571 * that decrements every 256 cycles.
572 *
573 * Try for a timeout of 5 sec, if that fails a smaller number
574 * of even seconds,
575 */
576 max_timeout_sec = 6;
577 do {
578 max_timeout_sec--;
579 timeout_cnt = ((octeon_get_io_clock_rate() >> 8) *
580 max_timeout_sec) >> 8;
581 } while (timeout_cnt > 65535);
582
583 BUG_ON(timeout_cnt == 0);
584
585 octeon_wdt_calc_parameters(heartbeat);
586
587 pr_info("Initial granularity %d Sec\n", timeout_sec);
588
589 octeon_wdt.timeout = timeout_sec;
590 octeon_wdt.max_timeout = UINT_MAX;
591
592 watchdog_set_nowayout(&octeon_wdt, nowayout);
593
594 ret = watchdog_register_device(&octeon_wdt);
595 if (ret) {
596 pr_err("watchdog_register_device() failed: %d\n", ret);
597 return ret;
598 }
599
600 /* Build the NMI handler ... */
601 octeon_wdt_build_stage1();
602
603 /* ... and install it. */
604 ptr = (u64 *) nmi_stage1_insns;
605 for (i = 0; i < 16; i++) {
606 cvmx_write_csr(CVMX_MIO_BOOT_LOC_ADR, i * 8);
607 cvmx_write_csr(CVMX_MIO_BOOT_LOC_DAT, ptr[i]);
608 }
609 cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0x81fc0000);
610
611 cpumask_clear(&irq_enabled_cpus);
612
613 cpu_notifier_register_begin();
614 for_each_online_cpu(cpu)
615 octeon_wdt_setup_interrupt(cpu);
616
617 __register_hotcpu_notifier(&octeon_wdt_cpu_notifier);
618 cpu_notifier_register_done();
619
620 return 0;
621}
622
623/**
624 * Module / driver shutdown
625 */
626static void __exit octeon_wdt_cleanup(void)
627{
628 int cpu;
629
630 watchdog_unregister_device(&octeon_wdt);
631
632 cpu_notifier_register_begin();
633 __unregister_hotcpu_notifier(&octeon_wdt_cpu_notifier);
634
635 for_each_online_cpu(cpu) {
636 int core = cpu2core(cpu);
637 /* Disable the watchdog */
638 cvmx_write_csr(CVMX_CIU_WDOGX(core), 0);
639 /* Free the interrupt handler */
640 free_irq(OCTEON_IRQ_WDOG0 + core, octeon_wdt_poke_irq);
641 }
642
643 cpu_notifier_register_done();
644
645 /*
646 * Disable the boot-bus memory, the code it points to is soon
647 * to go missing.
648 */
649 cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0);
650}
651
652MODULE_LICENSE("GPL");
653MODULE_AUTHOR("Cavium Networks <support@caviumnetworks.com>");
654MODULE_DESCRIPTION("Cavium Networks Octeon Watchdog driver.");
655module_init(octeon_wdt_init);
656module_exit(octeon_wdt_cleanup);