// SPDX-License-Identifier: GPL-2.0+ /* * Octeon Watchdog driver * * Copyright (C) 2007-2017 Cavium, Inc. * * Converted to use WATCHDOG_CORE by Aaro Koskinen <aaro.koskinen@iki.fi>. * * Some parts derived from wdt.c * * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, * All Rights Reserved. * * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide * warranty for any of this software. This material is provided * "AS-IS" and at no charge. * * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> * * The OCTEON watchdog has a maximum timeout of 2^32 * io_clock. * For most systems this is less than 10 seconds, so to allow for * software to request longer watchdog heartbeats, we maintain software * counters to count multiples of the base rate. If the system locks * up in such a manner that we can not run the software counters, the * only result is a watchdog reset sooner than was requested. But * that is OK, because in this case userspace would likely not be able * to do anything anyhow. * * The hardware watchdog interval we call the period. The OCTEON * watchdog goes through several stages, after the first period an * irq is asserted, then if it is not reset, after the next period NMI * is asserted, then after an additional period a chip wide soft reset. * So for the software counters, we reset watchdog after each period * and decrement the counter. But for the last two periods we need to * let the watchdog progress to the NMI stage so we disable the irq * and let it proceed. Once in the NMI, we print the register state * to the serial port and then wait for the reset. * * A watchdog is maintained for each CPU in the system, that way if * one CPU suffers a lockup, we also get a register dump and reset. * The userspace ping resets the watchdog on all CPUs. * * Before userspace opens the watchdog device, we still run the * watchdogs to catch any lockups that may be kernel related. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/interrupt.h> #include <linux/watchdog.h> #include <linux/cpumask.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/cpu.h> #include <linux/irq.h> #include <asm/mipsregs.h> #include <asm/uasm.h> #include <asm/octeon/octeon.h> #include <asm/octeon/cvmx-boot-vector.h> #include <asm/octeon/cvmx-ciu2-defs.h> #include <asm/octeon/cvmx-rst-defs.h> /* Watchdog interrupt major block number (8 MSBs of intsn) */ #define WD_BLOCK_NUMBER 0x01 static int divisor; /* The count needed to achieve timeout_sec. */ static unsigned int timeout_cnt; /* The maximum period supported. */ static unsigned int max_timeout_sec; /* The current period. */ static unsigned int timeout_sec; /* Set to non-zero when userspace countdown mode active */ static bool do_countdown; static unsigned int countdown_reset; static unsigned int per_cpu_countdown[NR_CPUS]; static cpumask_t irq_enabled_cpus; #define WD_TIMO 60 /* Default heartbeat = 60 seconds */ #define CVMX_GSERX_SCRATCH(offset) (CVMX_ADD_IO_SEG(0x0001180090000020ull) + ((offset) & 15) * 0x1000000ull) static int heartbeat = WD_TIMO; module_param(heartbeat, int, 0444); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (0 < heartbeat, default=" __MODULE_STRING(WD_TIMO) ")"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0444); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static int disable; module_param(disable, int, 0444); MODULE_PARM_DESC(disable, "Disable the watchdog entirely (default=0)"); static struct cvmx_boot_vector_element *octeon_wdt_bootvector; void octeon_wdt_nmi_stage2(void); static int cpu2core(int cpu) { #ifdef CONFIG_SMP return cpu_logical_map(cpu) & 0x3f; #else return cvmx_get_core_num(); #endif } /** * Poke the watchdog when an interrupt is received * * @cpl: * @dev_id: * * Returns */ static irqreturn_t octeon_wdt_poke_irq(int cpl, void *dev_id) { int cpu = raw_smp_processor_id(); unsigned int core = cpu2core(cpu); int node = cpu_to_node(cpu); if (do_countdown) { if (per_cpu_countdown[cpu] > 0) { /* We're alive, poke the watchdog */ cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1); per_cpu_countdown[cpu]--; } else { /* Bad news, you are about to reboot. */ disable_irq_nosync(cpl); cpumask_clear_cpu(cpu, &irq_enabled_cpus); } } else { /* Not open, just ping away... */ cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1); } return IRQ_HANDLED; } /* From setup.c */ extern int prom_putchar(char c); /** * Write a string to the uart * * @str: String to write */ static void octeon_wdt_write_string(const char *str) { /* Just loop writing one byte at a time */ while (*str) prom_putchar(*str++); } /** * Write a hex number out of the uart * * @value: Number to display * @digits: Number of digits to print (1 to 16) */ static void octeon_wdt_write_hex(u64 value, int digits) { int d; int v; for (d = 0; d < digits; d++) { v = (value >> ((digits - d - 1) * 4)) & 0xf; if (v >= 10) prom_putchar('a' + v - 10); else prom_putchar('0' + v); } } static const char reg_name[][3] = { "$0", "at", "v0", "v1", "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3", "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7", "t8", "t9", "k0", "k1", "gp", "sp", "s8", "ra" }; /** * NMI stage 3 handler. NMIs are handled in the following manner: * 1) The first NMI handler enables CVMSEG and transfers from * the bootbus region into normal memory. It is careful to not * destroy any registers. * 2) The second stage handler uses CVMSEG to save the registers * and create a stack for C code. It then calls the third level * handler with one argument, a pointer to the register values. * 3) The third, and final, level handler is the following C * function that prints out some useful infomration. * * @reg: Pointer to register state before the NMI */ void octeon_wdt_nmi_stage3(u64 reg[32]) { u64 i; unsigned int coreid = cvmx_get_core_num(); /* * Save status and cause early to get them before any changes * might happen. */ u64 cp0_cause = read_c0_cause(); u64 cp0_status = read_c0_status(); u64 cp0_error_epc = read_c0_errorepc(); u64 cp0_epc = read_c0_epc(); /* Delay so output from all cores output is not jumbled together. */ udelay(85000 * coreid); octeon_wdt_write_string("\r\n*** NMI Watchdog interrupt on Core 0x"); octeon_wdt_write_hex(coreid, 2); octeon_wdt_write_string(" ***\r\n"); for (i = 0; i < 32; i++) { octeon_wdt_write_string("\t"); octeon_wdt_write_string(reg_name[i]); octeon_wdt_write_string("\t0x"); octeon_wdt_write_hex(reg[i], 16); if (i & 1) octeon_wdt_write_string("\r\n"); } octeon_wdt_write_string("\terr_epc\t0x"); octeon_wdt_write_hex(cp0_error_epc, 16); octeon_wdt_write_string("\tepc\t0x"); octeon_wdt_write_hex(cp0_epc, 16); octeon_wdt_write_string("\r\n"); octeon_wdt_write_string("\tstatus\t0x"); octeon_wdt_write_hex(cp0_status, 16); octeon_wdt_write_string("\tcause\t0x"); octeon_wdt_write_hex(cp0_cause, 16); octeon_wdt_write_string("\r\n"); /* The CIU register is different for each Octeon model. */ if (OCTEON_IS_MODEL(OCTEON_CN68XX)) { octeon_wdt_write_string("\tsrc_wd\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SRC_PPX_IP2_WDOG(coreid)), 16); octeon_wdt_write_string("\ten_wd\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_EN_PPX_IP2_WDOG(coreid)), 16); octeon_wdt_write_string("\r\n"); octeon_wdt_write_string("\tsrc_rml\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SRC_PPX_IP2_RML(coreid)), 16); octeon_wdt_write_string("\ten_rml\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_EN_PPX_IP2_RML(coreid)), 16); octeon_wdt_write_string("\r\n"); octeon_wdt_write_string("\tsum\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU2_SUM_PPX_IP2(coreid)), 16); octeon_wdt_write_string("\r\n"); } else if (!octeon_has_feature(OCTEON_FEATURE_CIU3)) { octeon_wdt_write_string("\tsum0\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_SUM0(coreid * 2)), 16); octeon_wdt_write_string("\ten0\t0x"); octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_EN0(coreid * 2)), 16); octeon_wdt_write_string("\r\n"); } octeon_wdt_write_string("*** Chip soft reset soon ***\r\n"); /* * G-30204: We must trigger a soft reset before watchdog * does an incomplete job of doing it. */ if (OCTEON_IS_OCTEON3() && !OCTEON_IS_MODEL(OCTEON_CN70XX)) { u64 scr; unsigned int node = cvmx_get_node_num(); unsigned int lcore = cvmx_get_local_core_num(); union cvmx_ciu_wdogx ciu_wdog; /* * Wait for other cores to print out information, but * not too long. Do the soft reset before watchdog * can trigger it. */ do { ciu_wdog.u64 = cvmx_read_csr_node(node, CVMX_CIU_WDOGX(lcore)); } while (ciu_wdog.s.cnt > 0x10000); scr = cvmx_read_csr_node(0, CVMX_GSERX_SCRATCH(0)); scr |= 1 << 11; /* Indicate watchdog in bit 11 */ cvmx_write_csr_node(0, CVMX_GSERX_SCRATCH(0), scr); cvmx_write_csr_node(0, CVMX_RST_SOFT_RST, 1); } } static int octeon_wdt_cpu_to_irq(int cpu) { unsigned int coreid; int node; int irq; coreid = cpu2core(cpu); node = cpu_to_node(cpu); if (octeon_has_feature(OCTEON_FEATURE_CIU3)) { struct irq_domain *domain; int hwirq; domain = octeon_irq_get_block_domain(node, WD_BLOCK_NUMBER); hwirq = WD_BLOCK_NUMBER << 12 | 0x200 | coreid; irq = irq_find_mapping(domain, hwirq); } else { irq = OCTEON_IRQ_WDOG0 + coreid; } return irq; } static int octeon_wdt_cpu_pre_down(unsigned int cpu) { unsigned int core; int node; union cvmx_ciu_wdogx ciu_wdog; core = cpu2core(cpu); node = cpu_to_node(cpu); /* Poke the watchdog to clear out its state */ cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1); /* Disable the hardware. */ ciu_wdog.u64 = 0; cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64); free_irq(octeon_wdt_cpu_to_irq(cpu), octeon_wdt_poke_irq); return 0; } static int octeon_wdt_cpu_online(unsigned int cpu) { unsigned int core; unsigned int irq; union cvmx_ciu_wdogx ciu_wdog; int node; struct irq_domain *domain; int hwirq; core = cpu2core(cpu); node = cpu_to_node(cpu); octeon_wdt_bootvector[core].target_ptr = (u64)octeon_wdt_nmi_stage2; /* Disable it before doing anything with the interrupts. */ ciu_wdog.u64 = 0; cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64); per_cpu_countdown[cpu] = countdown_reset; if (octeon_has_feature(OCTEON_FEATURE_CIU3)) { /* Must get the domain for the watchdog block */ domain = octeon_irq_get_block_domain(node, WD_BLOCK_NUMBER); /* Get a irq for the wd intsn (hardware interrupt) */ hwirq = WD_BLOCK_NUMBER << 12 | 0x200 | core; irq = irq_create_mapping(domain, hwirq); irqd_set_trigger_type(irq_get_irq_data(irq), IRQ_TYPE_EDGE_RISING); } else irq = OCTEON_IRQ_WDOG0 + core; if (request_irq(irq, octeon_wdt_poke_irq, IRQF_NO_THREAD, "octeon_wdt", octeon_wdt_poke_irq)) panic("octeon_wdt: Couldn't obtain irq %d", irq); /* Must set the irq affinity here */ if (octeon_has_feature(OCTEON_FEATURE_CIU3)) { cpumask_t mask; cpumask_clear(&mask); cpumask_set_cpu(cpu, &mask); irq_set_affinity(irq, &mask); } cpumask_set_cpu(cpu, &irq_enabled_cpus); /* Poke the watchdog to clear out its state */ cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(core), 1); /* Finally enable the watchdog now that all handlers are installed */ ciu_wdog.u64 = 0; ciu_wdog.s.len = timeout_cnt; ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */ cvmx_write_csr_node(node, CVMX_CIU_WDOGX(core), ciu_wdog.u64); return 0; } static int octeon_wdt_ping(struct watchdog_device __always_unused *wdog) { int cpu; int coreid; int node; if (disable) return 0; for_each_online_cpu(cpu) { coreid = cpu2core(cpu); node = cpu_to_node(cpu); cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1); per_cpu_countdown[cpu] = countdown_reset; if ((countdown_reset || !do_countdown) && !cpumask_test_cpu(cpu, &irq_enabled_cpus)) { /* We have to enable the irq */ enable_irq(octeon_wdt_cpu_to_irq(cpu)); cpumask_set_cpu(cpu, &irq_enabled_cpus); } } return 0; } static void octeon_wdt_calc_parameters(int t) { unsigned int periods; timeout_sec = max_timeout_sec; /* * Find the largest interrupt period, that can evenly divide * the requested heartbeat time. */ while ((t % timeout_sec) != 0) timeout_sec--; periods = t / timeout_sec; /* * The last two periods are after the irq is disabled, and * then to the nmi, so we subtract them off. */ countdown_reset = periods > 2 ? periods - 2 : 0; heartbeat = t; timeout_cnt = ((octeon_get_io_clock_rate() / divisor) * timeout_sec) >> 8; } static int octeon_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) { int cpu; int coreid; union cvmx_ciu_wdogx ciu_wdog; int node; if (t <= 0) return -1; octeon_wdt_calc_parameters(t); if (disable) return 0; for_each_online_cpu(cpu) { coreid = cpu2core(cpu); node = cpu_to_node(cpu); cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1); ciu_wdog.u64 = 0; ciu_wdog.s.len = timeout_cnt; ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */ cvmx_write_csr_node(node, CVMX_CIU_WDOGX(coreid), ciu_wdog.u64); cvmx_write_csr_node(node, CVMX_CIU_PP_POKEX(coreid), 1); } octeon_wdt_ping(wdog); /* Get the irqs back on. */ return 0; } static int octeon_wdt_start(struct watchdog_device *wdog) { octeon_wdt_ping(wdog); do_countdown = 1; return 0; } static int octeon_wdt_stop(struct watchdog_device *wdog) { do_countdown = 0; octeon_wdt_ping(wdog); return 0; } static const struct watchdog_info octeon_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "OCTEON", }; static const struct watchdog_ops octeon_wdt_ops = { .owner = THIS_MODULE, .start = octeon_wdt_start, .stop = octeon_wdt_stop, .ping = octeon_wdt_ping, .set_timeout = octeon_wdt_set_timeout, }; static struct watchdog_device octeon_wdt = { .info = &octeon_wdt_info, .ops = &octeon_wdt_ops, }; static enum cpuhp_state octeon_wdt_online; /** * Module/ driver initialization. * * Returns Zero on success */ static int __init octeon_wdt_init(void) { int ret; octeon_wdt_bootvector = cvmx_boot_vector_get(); if (!octeon_wdt_bootvector) { pr_err("Error: Cannot allocate boot vector.\n"); return -ENOMEM; } if (OCTEON_IS_MODEL(OCTEON_CN68XX)) divisor = 0x200; else if (OCTEON_IS_MODEL(OCTEON_CN78XX)) divisor = 0x400; else divisor = 0x100; /* * Watchdog time expiration length = The 16 bits of LEN * represent the most significant bits of a 24 bit decrementer * that decrements every divisor cycle. * * Try for a timeout of 5 sec, if that fails a smaller number * of even seconds, */ max_timeout_sec = 6; do { max_timeout_sec--; timeout_cnt = ((octeon_get_io_clock_rate() / divisor) * max_timeout_sec) >> 8; } while (timeout_cnt > 65535); BUG_ON(timeout_cnt == 0); octeon_wdt_calc_parameters(heartbeat); pr_info("Initial granularity %d Sec\n", timeout_sec); octeon_wdt.timeout = timeout_sec; octeon_wdt.max_timeout = UINT_MAX; watchdog_set_nowayout(&octeon_wdt, nowayout); ret = watchdog_register_device(&octeon_wdt); if (ret) { pr_err("watchdog_register_device() failed: %d\n", ret); return ret; } if (disable) { pr_notice("disabled\n"); return 0; } cpumask_clear(&irq_enabled_cpus); ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "watchdog/octeon:online", octeon_wdt_cpu_online, octeon_wdt_cpu_pre_down); if (ret < 0) goto err; octeon_wdt_online = ret; return 0; err: cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0); watchdog_unregister_device(&octeon_wdt); return ret; } /** * Module / driver shutdown */ static void __exit octeon_wdt_cleanup(void) { watchdog_unregister_device(&octeon_wdt); if (disable) return; cpuhp_remove_state(octeon_wdt_online); /* * Disable the boot-bus memory, the code it points to is soon * to go missing. */ cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0); } MODULE_LICENSE("GPL"); MODULE_AUTHOR("Cavium Inc. <support@cavium.com>"); MODULE_DESCRIPTION("Cavium Inc. OCTEON Watchdog driver."); module_init(octeon_wdt_init); module_exit(octeon_wdt_cleanup);