+++ /dev/null
-/*
- * Blackfin nmi_watchdog Driver
- *
- * Originally based on bfin_wdt.c
- * Copyright 2010-2010 Analog Devices Inc.
- * Graff Yang <graf.yang@analog.com>
- *
- * Enter bugs at http://blackfin.uclinux.org/
- *
- * Licensed under the GPL-2 or later.
- */
-
-#include <linux/bitops.h>
-#include <linux/hardirq.h>
-#include <linux/syscore_ops.h>
-#include <linux/pm.h>
-#include <linux/nmi.h>
-#include <linux/smp.h>
-#include <linux/timer.h>
-#include <linux/sched/debug.h>
-#include <asm/blackfin.h>
-#include <linux/atomic.h>
-#include <asm/cacheflush.h>
-#include <asm/bfin_watchdog.h>
-
-#define DRV_NAME "nmi-wdt"
-
-#define NMI_WDT_TIMEOUT 5 /* 5 seconds */
-#define NMI_CHECK_TIMEOUT (4 * HZ) /* 4 seconds in jiffies */
-static int nmi_wdt_cpu = 1;
-
-static unsigned int timeout = NMI_WDT_TIMEOUT;
-static int nmi_active;
-
-static unsigned short wdoga_ctl;
-static unsigned int wdoga_cnt;
-static struct corelock_slot saved_corelock;
-static atomic_t nmi_touched[NR_CPUS];
-static struct timer_list ntimer;
-
-enum {
- COREA_ENTER_NMI = 0,
- COREA_EXIT_NMI,
- COREB_EXIT_NMI,
-
- NMI_EVENT_NR,
-};
-static unsigned long nmi_event __attribute__ ((__section__(".l2.bss")));
-
-/* we are in nmi, non-atomic bit ops is safe */
-static inline void set_nmi_event(int event)
-{
- __set_bit(event, &nmi_event);
-}
-
-static inline void wait_nmi_event(int event)
-{
- while (!test_bit(event, &nmi_event))
- barrier();
- __clear_bit(event, &nmi_event);
-}
-
-static inline void send_corea_nmi(void)
-{
- wdoga_ctl = bfin_read_WDOGA_CTL();
- wdoga_cnt = bfin_read_WDOGA_CNT();
-
- bfin_write_WDOGA_CTL(WDEN_DISABLE);
- bfin_write_WDOGA_CNT(0);
- bfin_write_WDOGA_CTL(WDEN_ENABLE | ICTL_NMI);
-}
-
-static inline void restore_corea_nmi(void)
-{
- bfin_write_WDOGA_CTL(WDEN_DISABLE);
- bfin_write_WDOGA_CTL(WDOG_EXPIRED | WDEN_DISABLE | ICTL_NONE);
-
- bfin_write_WDOGA_CNT(wdoga_cnt);
- bfin_write_WDOGA_CTL(wdoga_ctl);
-}
-
-static inline void save_corelock(void)
-{
- saved_corelock = corelock;
- corelock.lock = 0;
-}
-
-static inline void restore_corelock(void)
-{
- corelock = saved_corelock;
-}
-
-
-static inline void nmi_wdt_keepalive(void)
-{
- bfin_write_WDOGB_STAT(0);
-}
-
-static inline void nmi_wdt_stop(void)
-{
- bfin_write_WDOGB_CTL(WDEN_DISABLE);
-}
-
-/* before calling this function, you must stop the WDT */
-static inline void nmi_wdt_clear(void)
-{
- /* clear TRO bit, disable event generation */
- bfin_write_WDOGB_CTL(WDOG_EXPIRED | WDEN_DISABLE | ICTL_NONE);
-}
-
-static inline void nmi_wdt_start(void)
-{
- bfin_write_WDOGB_CTL(WDEN_ENABLE | ICTL_NMI);
-}
-
-static inline int nmi_wdt_running(void)
-{
- return ((bfin_read_WDOGB_CTL() & WDEN_MASK) != WDEN_DISABLE);
-}
-
-static inline int nmi_wdt_set_timeout(unsigned long t)
-{
- u32 cnt, max_t, sclk;
- int run;
-
- sclk = get_sclk();
- max_t = -1 / sclk;
- cnt = t * sclk;
- if (t > max_t) {
- pr_warning("NMI: timeout value is too large\n");
- return -EINVAL;
- }
-
- run = nmi_wdt_running();
- nmi_wdt_stop();
- bfin_write_WDOGB_CNT(cnt);
- if (run)
- nmi_wdt_start();
-
- timeout = t;
-
- return 0;
-}
-
-int check_nmi_wdt_touched(void)
-{
- unsigned int this_cpu = smp_processor_id();
- unsigned int cpu;
- cpumask_t mask;
-
- cpumask_copy(&mask, cpu_online_mask);
- if (!atomic_read(&nmi_touched[this_cpu]))
- return 0;
-
- atomic_set(&nmi_touched[this_cpu], 0);
-
- cpumask_clear_cpu(this_cpu, &mask);
- for_each_cpu(cpu, &mask) {
- invalidate_dcache_range((unsigned long)(&nmi_touched[cpu]),
- (unsigned long)(&nmi_touched[cpu]));
- if (!atomic_read(&nmi_touched[cpu]))
- return 0;
- atomic_set(&nmi_touched[cpu], 0);
- }
-
- return 1;
-}
-
-static void nmi_wdt_timer(struct timer_list *unused)
-{
- if (check_nmi_wdt_touched())
- nmi_wdt_keepalive();
-
- mod_timer(&ntimer, jiffies + NMI_CHECK_TIMEOUT);
-}
-
-static int __init init_nmi_wdt(void)
-{
- nmi_wdt_set_timeout(timeout);
- nmi_wdt_start();
- nmi_active = true;
-
- timer_setup(&ntimer, nmi_wdt_timer, 0);
- ntimer.expires = jiffies + NMI_CHECK_TIMEOUT;
- add_timer(&ntimer);
-
- pr_info("nmi_wdt: initialized: timeout=%d sec\n", timeout);
- return 0;
-}
-device_initcall(init_nmi_wdt);
-
-void arch_touch_nmi_watchdog(void)
-{
- atomic_set(&nmi_touched[smp_processor_id()], 1);
-}
-
-/* Suspend/resume support */
-#ifdef CONFIG_PM
-static int nmi_wdt_suspend(void)
-{
- nmi_wdt_stop();
- return 0;
-}
-
-static void nmi_wdt_resume(void)
-{
- if (nmi_active)
- nmi_wdt_start();
-}
-
-static struct syscore_ops nmi_syscore_ops = {
- .resume = nmi_wdt_resume,
- .suspend = nmi_wdt_suspend,
-};
-
-static int __init init_nmi_wdt_syscore(void)
-{
- if (nmi_active)
- register_syscore_ops(&nmi_syscore_ops);
-
- return 0;
-}
-late_initcall(init_nmi_wdt_syscore);
-
-#endif /* CONFIG_PM */
-
-
-asmlinkage notrace void do_nmi(struct pt_regs *fp)
-{
- unsigned int cpu = smp_processor_id();
- nmi_enter();
-
- cpu_pda[cpu].__nmi_count += 1;
-
- if (cpu == nmi_wdt_cpu) {
- /* CoreB goes here first */
-
- /* reload the WDOG_STAT */
- nmi_wdt_keepalive();
-
- /* clear nmi interrupt for CoreB */
- nmi_wdt_stop();
- nmi_wdt_clear();
-
- /* trigger NMI interrupt of CoreA */
- send_corea_nmi();
-
- /* waiting CoreB to enter NMI */
- wait_nmi_event(COREA_ENTER_NMI);
-
- /* recover WDOGA's settings */
- restore_corea_nmi();
-
- save_corelock();
-
- /* corelock is save/cleared, CoreA is dummping messages */
-
- wait_nmi_event(COREA_EXIT_NMI);
- } else {
- /* OK, CoreA entered NMI */
- set_nmi_event(COREA_ENTER_NMI);
- }
-
- pr_emerg("\nNMI Watchdog detected LOCKUP, dump for CPU %d\n", cpu);
- dump_bfin_process(fp);
- dump_bfin_mem(fp);
- show_regs(fp);
- dump_bfin_trace_buffer();
- show_stack(current, (unsigned long *)fp);
-
- if (cpu == nmi_wdt_cpu) {
- pr_emerg("This fault is not recoverable, sorry!\n");
-
- /* CoreA dump finished, restore the corelock */
- restore_corelock();
-
- set_nmi_event(COREB_EXIT_NMI);
- } else {
- /* CoreB dump finished, notice the CoreA we are done */
- set_nmi_event(COREA_EXIT_NMI);
-
- /* synchronize with CoreA */
- wait_nmi_event(COREB_EXIT_NMI);
- }
-
- nmi_exit();
-}
git.samba.org / sfrench / cifs-2.6.git / blobdiff