WATCHDOG: Add watchdog driver for OCTEON SOCs
The OCTEON is a MIPS64 based SOC family with an on chip watchdog unit.
The driver is split into two source files one for the C code and one
for assembly. Assembly is needed to handle the NMI and then print the
machine state before the reboot is triggered.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Marc Zyngier <maz@misterjones.org>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
To: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org,
Patchwork: https://patchwork.linux-mips.org/patch/1503/
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
create mode 100644 drivers/watchdog/octeon-wdt-main.c
create mode 100644 drivers/watchdog/octeon-wdt-nmi.S
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index afcfacc..b04b184 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -875,6 +875,24 @@
help
Hardware driver for the built-in watchdog timer on TXx9 MIPS SoCs.
+config OCTEON_WDT
+ tristate "Cavium OCTEON SOC family Watchdog Timer"
+ depends on CPU_CAVIUM_OCTEON
+ default y
+ select EXPORT_UASM if OCTEON_WDT = m
+ help
+ Hardware driver for OCTEON's on chip watchdog timer.
+ Enables the watchdog for all cores running Linux. It
+ installs a NMI handler and pokes the watchdog based on an
+ interrupt. On first expiration of the watchdog, the
+ interrupt handler pokes it. The second expiration causes an
+ NMI that prints a message. The third expiration causes a
+ global soft reset.
+
+ When userspace has /dev/watchdog open, no poking is done
+ from the first interrupt, it is then only poked when the
+ device is written.
+
# PARISC Architecture
# POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 72f3e20..e30289a 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -114,6 +114,8 @@
obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
+obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
+octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
# PARISC Architecture
diff --git a/drivers/watchdog/octeon-wdt-main.c b/drivers/watchdog/octeon-wdt-main.c
new file mode 100644
index 0000000..2a41017
--- /dev/null
+++ b/drivers/watchdog/octeon-wdt-main.c
@@ -0,0 +1,745 @@
+/*
+ * Octeon Watchdog driver
+ *
+ * Copyright (C) 2007, 2008, 2009, 2010 Cavium Networks
+ *
+ * Some parts derived from wdt.c
+ *
+ * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * 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>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ *
+ * 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.
+ *
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/interrupt.h>
+#include <linux/watchdog.h>
+#include <linux/cpumask.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/fs.h>
+
+#include <asm/mipsregs.h>
+#include <asm/uasm.h>
+
+#include <asm/octeon/octeon.h>
+
+/* 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 int do_coundown;
+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 */
+
+static int heartbeat = WD_TIMO;
+module_param(heartbeat, int, S_IRUGO);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat in seconds. (0 < heartbeat, default="
+ __MODULE_STRING(WD_TIMO) ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, S_IRUGO);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned long octeon_wdt_is_open;
+static char expect_close;
+
+static u32 __initdata nmi_stage1_insns[64];
+/* We need one branch and therefore one relocation per target label. */
+static struct uasm_label __initdata labels[5];
+static struct uasm_reloc __initdata relocs[5];
+
+enum lable_id {
+ label_enter_bootloader = 1
+};
+
+/* Some CP0 registers */
+#define K0 26
+#define C0_CVMMEMCTL 11, 7
+#define C0_STATUS 12, 0
+#define C0_EBASE 15, 1
+#define C0_DESAVE 31, 0
+
+void octeon_wdt_nmi_stage2(void);
+
+static void __init octeon_wdt_build_stage1(void)
+{
+ int i;
+ int len;
+ u32 *p = nmi_stage1_insns;
+#ifdef CONFIG_HOTPLUG_CPU
+ struct uasm_label *l = labels;
+ struct uasm_reloc *r = relocs;
+#endif
+
+ /*
+ * For the next few instructions running the debugger may
+ * cause corruption of k0 in the saved registers. Since we're
+ * about to crash, nobody probably cares.
+ *
+ * Save K0 into the debug scratch register
+ */
+ uasm_i_dmtc0(&p, K0, C0_DESAVE);
+
+ uasm_i_mfc0(&p, K0, C0_STATUS);
+#ifdef CONFIG_HOTPLUG_CPU
+ uasm_il_bbit0(&p, &r, K0, ilog2(ST0_NMI), label_enter_bootloader);
+#endif
+ /* Force 64-bit addressing enabled */
+ uasm_i_ori(&p, K0, K0, ST0_UX | ST0_SX | ST0_KX);
+ uasm_i_mtc0(&p, K0, C0_STATUS);
+
+#ifdef CONFIG_HOTPLUG_CPU
+ uasm_i_mfc0(&p, K0, C0_EBASE);
+ /* Coreid number in K0 */
+ uasm_i_andi(&p, K0, K0, 0xf);
+ /* 8 * coreid in bits 16-31 */
+ uasm_i_dsll_safe(&p, K0, K0, 3 + 16);
+ uasm_i_ori(&p, K0, K0, 0x8001);
+ uasm_i_dsll_safe(&p, K0, K0, 16);
+ uasm_i_ori(&p, K0, K0, 0x0700);
+ uasm_i_drotr_safe(&p, K0, K0, 32);
+ /*
+ * Should result in: 0x8001,0700,0000,8*coreid which is
+ * CVMX_CIU_WDOGX(coreid) - 0x0500
+ *
+ * Now ld K0, CVMX_CIU_WDOGX(coreid)
+ */
+ uasm_i_ld(&p, K0, 0x500, K0);
+ /*
+ * If bit one set handle the NMI as a watchdog event.
+ * otherwise transfer control to bootloader.
+ */
+ uasm_il_bbit0(&p, &r, K0, 1, label_enter_bootloader);
+ uasm_i_nop(&p);
+#endif
+
+ /* Clear Dcache so cvmseg works right. */
+ uasm_i_cache(&p, 1, 0, 0);
+
+ /* Use K0 to do a read/modify/write of CVMMEMCTL */
+ uasm_i_dmfc0(&p, K0, C0_CVMMEMCTL);
+ /* Clear out the size of CVMSEG */
+ uasm_i_dins(&p, K0, 0, 0, 6);
+ /* Set CVMSEG to its largest value */
+ uasm_i_ori(&p, K0, K0, 0x1c0 | 54);
+ /* Store the CVMMEMCTL value */
+ uasm_i_dmtc0(&p, K0, C0_CVMMEMCTL);
+
+ /* Load the address of the second stage handler */
+ UASM_i_LA(&p, K0, (long)octeon_wdt_nmi_stage2);
+ uasm_i_jr(&p, K0);
+ uasm_i_dmfc0(&p, K0, C0_DESAVE);
+
+#ifdef CONFIG_HOTPLUG_CPU
+ uasm_build_label(&l, p, label_enter_bootloader);
+ /* Jump to the bootloader and restore K0 */
+ UASM_i_LA(&p, K0, (long)octeon_bootloader_entry_addr);
+ uasm_i_jr(&p, K0);
+ uasm_i_dmfc0(&p, K0, C0_DESAVE);
+#endif
+ uasm_resolve_relocs(relocs, labels);
+
+ len = (int)(p - nmi_stage1_insns);
+ pr_debug("Synthesized NMI stage 1 handler (%d instructions).\n", len);
+
+ pr_debug("\t.set push\n");
+ pr_debug("\t.set noreorder\n");
+ for (i = 0; i < len; i++)
+ pr_debug("\t.word 0x%08x\n", nmi_stage1_insns[i]);
+ pr_debug("\t.set pop\n");
+
+ if (len > 32)
+ panic("NMI stage 1 handler exceeds 32 instructions, was %d\n", len);
+}
+
+static int cpu2core(int cpu)
+{
+#ifdef CONFIG_SMP
+ return cpu_logical_map(cpu);
+#else
+ return cvmx_get_core_num();
+#endif
+}
+
+static int core2cpu(int coreid)
+{
+#ifdef CONFIG_SMP
+ return cpu_number_map(coreid);
+#else
+ return 0;
+#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)
+{
+ unsigned int core = cvmx_get_core_num();
+ int cpu = core2cpu(core);
+
+ if (do_coundown) {
+ if (per_cpu_countdown[cpu] > 0) {
+ /* We're alive, poke the watchdog */
+ cvmx_write_csr(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(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);
+ }
+}
+
+const char *reg_name[] = {
+ "$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. */
+ __delay(100000000ull * coreid);
+
+ octeon_wdt_write_string("\r\n*** NMI Watchdog interrupt on Core 0x");
+ octeon_wdt_write_hex(coreid, 1);
+ 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");
+
+ 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");
+}
+
+static void octeon_wdt_disable_interrupt(int cpu)
+{
+ unsigned int core;
+ unsigned int irq;
+ union cvmx_ciu_wdogx ciu_wdog;
+
+ core = cpu2core(cpu);
+
+ irq = OCTEON_IRQ_WDOG0 + core;
+
+ /* Poke the watchdog to clear out its state */
+ cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
+
+ /* Disable the hardware. */
+ ciu_wdog.u64 = 0;
+ cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
+
+ free_irq(irq, octeon_wdt_poke_irq);
+}
+
+static void octeon_wdt_setup_interrupt(int cpu)
+{
+ unsigned int core;
+ unsigned int irq;
+ union cvmx_ciu_wdogx ciu_wdog;
+
+ core = cpu2core(cpu);
+
+ /* Disable it before doing anything with the interrupts. */
+ ciu_wdog.u64 = 0;
+ cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
+
+ per_cpu_countdown[cpu] = countdown_reset;
+
+ irq = OCTEON_IRQ_WDOG0 + core;
+
+ if (request_irq(irq, octeon_wdt_poke_irq,
+ IRQF_DISABLED, "octeon_wdt", octeon_wdt_poke_irq))
+ panic("octeon_wdt: Couldn't obtain irq %d", irq);
+
+ cpumask_set_cpu(cpu, &irq_enabled_cpus);
+
+ /* Poke the watchdog to clear out its state */
+ cvmx_write_csr(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(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
+}
+
+static int octeon_wdt_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+
+ switch (action) {
+ case CPU_DOWN_PREPARE:
+ octeon_wdt_disable_interrupt(cpu);
+ break;
+ case CPU_ONLINE:
+ case CPU_DOWN_FAILED:
+ octeon_wdt_setup_interrupt(cpu);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static void octeon_wdt_ping(void)
+{
+ int cpu;
+ int coreid;
+
+ for_each_online_cpu(cpu) {
+ coreid = cpu2core(cpu);
+ cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
+ per_cpu_countdown[cpu] = countdown_reset;
+ if ((countdown_reset || !do_coundown) &&
+ !cpumask_test_cpu(cpu, &irq_enabled_cpus)) {
+ /* We have to enable the irq */
+ int irq = OCTEON_IRQ_WDOG0 + coreid;
+ enable_irq(irq);
+ cpumask_set_cpu(cpu, &irq_enabled_cpus);
+ }
+ }
+}
+
+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_clock_rate() >> 8) * timeout_sec) >> 8;
+}
+
+static int octeon_wdt_set_heartbeat(int t)
+{
+ int cpu;
+ int coreid;
+ union cvmx_ciu_wdogx ciu_wdog;
+
+ if (t <= 0)
+ return -1;
+
+ octeon_wdt_calc_parameters(t);
+
+ for_each_online_cpu(cpu) {
+ coreid = cpu2core(cpu);
+ cvmx_write_csr(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(CVMX_CIU_WDOGX(coreid), ciu_wdog.u64);
+ cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
+ }
+ octeon_wdt_ping(); /* Get the irqs back on. */
+ return 0;
+}
+
+/**
+ * octeon_wdt_write:
+ * @file: file handle to the watchdog
+ * @buf: buffer to write (unused as data does not matter here
+ * @count: count of bytes
+ * @ppos: pointer to the position to write. No seeks allowed
+ *
+ * A write to a watchdog device is defined as a keepalive signal. Any
+ * write of data will do, as we we don't define content meaning.
+ */
+
+static ssize_t octeon_wdt_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (count) {
+ if (!nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ expect_close = 0;
+
+ for (i = 0; i != count; i++) {
+ char c;
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 1;
+ }
+ }
+ octeon_wdt_ping();
+ }
+ return count;
+}
+
+/**
+ * octeon_wdt_ioctl:
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all
+ * watchdogs according to their available features. We only
+ * actually usefully support querying capabilities and setting
+ * the timeout.
+ */
+
+static long octeon_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_heartbeat;
+
+ static struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT|
+ WDIOF_MAGICCLOSE|
+ WDIOF_KEEPALIVEPING,
+ .firmware_version = 1,
+ .identity = "OCTEON",
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_KEEPALIVE:
+ octeon_wdt_ping();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_heartbeat, p))
+ return -EFAULT;
+ if (octeon_wdt_set_heartbeat(new_heartbeat))
+ return -EINVAL;
+ /* Fall through. */
+ case WDIOC_GETTIMEOUT:
+ return put_user(heartbeat, p);
+ default:
+ return -ENOTTY;
+ }
+}
+
+/**
+ * octeon_wdt_open:
+ * @inode: inode of device
+ * @file: file handle to device
+ *
+ * The watchdog device has been opened. The watchdog device is single
+ * open and on opening we do a ping to reset the counters.
+ */
+
+static int octeon_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &octeon_wdt_is_open))
+ return -EBUSY;
+ /*
+ * Activate
+ */
+ octeon_wdt_ping();
+ do_coundown = 1;
+ return nonseekable_open(inode, file);
+}
+
+/**
+ * octeon_wdt_release:
+ * @inode: inode to board
+ * @file: file handle to board
+ *
+ * The watchdog has a configurable API. There is a religious dispute
+ * between people who want their watchdog to be able to shut down and
+ * those who want to be sure if the watchdog manager dies the machine
+ * reboots. In the former case we disable the counters, in the latter
+ * case you have to open it again very soon.
+ */
+
+static int octeon_wdt_release(struct inode *inode, struct file *file)
+{
+ if (expect_close) {
+ do_coundown = 0;
+ octeon_wdt_ping();
+ } else {
+ pr_crit("octeon_wdt: WDT device closed unexpectedly. WDT will not stop!\n");
+ }
+ clear_bit(0, &octeon_wdt_is_open);
+ expect_close = 0;
+ return 0;
+}
+
+static const struct file_operations octeon_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = octeon_wdt_write,
+ .unlocked_ioctl = octeon_wdt_ioctl,
+ .open = octeon_wdt_open,
+ .release = octeon_wdt_release,
+};
+
+static struct miscdevice octeon_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &octeon_wdt_fops,
+};
+
+static struct notifier_block octeon_wdt_cpu_notifier = {
+ .notifier_call = octeon_wdt_cpu_callback,
+};
+
+
+/**
+ * Module/ driver initialization.
+ *
+ * Returns Zero on success
+ */
+static int __init octeon_wdt_init(void)
+{
+ int i;
+ int ret;
+ int cpu;
+ u64 *ptr;
+
+ /*
+ * Watchdog time expiration length = The 16 bits of LEN
+ * represent the most significant bits of a 24 bit decrementer
+ * that decrements every 256 cycles.
+ *
+ * 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_clock_rate() >> 8) * max_timeout_sec) >> 8;
+ } while (timeout_cnt > 65535);
+
+ BUG_ON(timeout_cnt == 0);
+
+ octeon_wdt_calc_parameters(heartbeat);
+
+ pr_info("octeon_wdt: Initial granularity %d Sec.\n", timeout_sec);
+
+ ret = misc_register(&octeon_wdt_miscdev);
+ if (ret) {
+ pr_err("octeon_wdt: cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto out;
+ }
+
+ /* Build the NMI handler ... */
+ octeon_wdt_build_stage1();
+
+ /* ... and install it. */
+ ptr = (u64 *) nmi_stage1_insns;
+ for (i = 0; i < 16; i++) {
+ cvmx_write_csr(CVMX_MIO_BOOT_LOC_ADR, i * 8);
+ cvmx_write_csr(CVMX_MIO_BOOT_LOC_DAT, ptr[i]);
+ }
+ cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0x81fc0000);
+
+ cpumask_clear(&irq_enabled_cpus);
+
+ for_each_online_cpu(cpu)
+ octeon_wdt_setup_interrupt(cpu);
+
+ register_hotcpu_notifier(&octeon_wdt_cpu_notifier);
+out:
+ return ret;
+}
+
+/**
+ * Module / driver shutdown
+ */
+static void __exit octeon_wdt_cleanup(void)
+{
+ int cpu;
+
+ misc_deregister(&octeon_wdt_miscdev);
+
+ unregister_hotcpu_notifier(&octeon_wdt_cpu_notifier);
+
+ for_each_online_cpu(cpu) {
+ int core = cpu2core(cpu);
+ /* Disable the watchdog */
+ cvmx_write_csr(CVMX_CIU_WDOGX(core), 0);
+ /* Free the interrupt handler */
+ free_irq(OCTEON_IRQ_WDOG0 + core, octeon_wdt_poke_irq);
+ }
+ /*
+ * 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 Networks <support@caviumnetworks.com>");
+MODULE_DESCRIPTION("Cavium Networks Octeon Watchdog driver.");
+module_init(octeon_wdt_init);
+module_exit(octeon_wdt_cleanup);
diff --git a/drivers/watchdog/octeon-wdt-nmi.S b/drivers/watchdog/octeon-wdt-nmi.S
new file mode 100644
index 0000000..8a900a5
--- /dev/null
+++ b/drivers/watchdog/octeon-wdt-nmi.S
@@ -0,0 +1,64 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2007 Cavium Networks
+ */
+#include <asm/asm.h>
+#include <asm/regdef.h>
+
+#define SAVE_REG(r) sd $r, -32768+6912-(32-r)*8($0)
+
+ NESTED(octeon_wdt_nmi_stage2, 0, sp)
+ .set push
+ .set noreorder
+ .set noat
+ /* Save all registers to the top CVMSEG. This shouldn't
+ * corrupt any state used by the kernel. Also all registers
+ * should have the value right before the NMI. */
+ SAVE_REG(0)
+ SAVE_REG(1)
+ SAVE_REG(2)
+ SAVE_REG(3)
+ SAVE_REG(4)
+ SAVE_REG(5)
+ SAVE_REG(6)
+ SAVE_REG(7)
+ SAVE_REG(8)
+ SAVE_REG(9)
+ SAVE_REG(10)
+ SAVE_REG(11)
+ SAVE_REG(12)
+ SAVE_REG(13)
+ SAVE_REG(14)
+ SAVE_REG(15)
+ SAVE_REG(16)
+ SAVE_REG(17)
+ SAVE_REG(18)
+ SAVE_REG(19)
+ SAVE_REG(20)
+ SAVE_REG(21)
+ SAVE_REG(22)
+ SAVE_REG(23)
+ SAVE_REG(24)
+ SAVE_REG(25)
+ SAVE_REG(26)
+ SAVE_REG(27)
+ SAVE_REG(28)
+ SAVE_REG(29)
+ SAVE_REG(30)
+ SAVE_REG(31)
+ /* Set the stack to begin right below the registers */
+ li sp, -32768+6912-32*8
+ /* Load the address of the third stage handler */
+ dla a0, octeon_wdt_nmi_stage3
+ /* Call the third stage handler */
+ jal a0
+ /* a0 is the address of the saved registers */
+ move a0, sp
+ /* Loop forvever if we get here. */
+1: b 1b
+ nop
+ .set pop
+ END(octeon_wdt_nmi_stage2)
