Commit | Line | Data |
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b920de1b DH |
1 | /* MN10300 Watchdog timer |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * - Derived from arch/i386/kernel/nmi.c | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public Licence | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the Licence, or (at your option) any later version. | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/kernel_stat.h> | |
19 | #include <linux/nmi.h> | |
20 | #include <asm/processor.h> | |
60063497 | 21 | #include <linux/atomic.h> |
b920de1b DH |
22 | #include <asm/intctl-regs.h> |
23 | #include <asm/rtc-regs.h> | |
24 | #include <asm/div64.h> | |
25 | #include <asm/smp.h> | |
26 | #include <asm/gdb-stub.h> | |
2f2a2132 | 27 | #include <proc/clock.h> |
b920de1b DH |
28 | |
29 | static DEFINE_SPINLOCK(watchdog_print_lock); | |
30 | static unsigned int watchdog; | |
31 | static unsigned int watchdog_hz = 1; | |
368dd5ac | 32 | unsigned int watchdog_alert_counter[NR_CPUS]; |
b920de1b DH |
33 | |
34 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
35 | ||
36 | /* | |
37 | * the best way to detect whether a CPU has a 'hard lockup' problem | |
38 | * is to check its timer makes IRQ counts. If they are not | |
39 | * changing then that CPU has some problem. | |
40 | * | |
b920de1b DH |
41 | * since NMIs dont listen to _any_ locks, we have to be extremely |
42 | * careful not to rely on unsafe variables. The printk might lock | |
43 | * up though, so we have to break up any console locks first ... | |
44 | * [when there will be more tty-related locks, break them up | |
45 | * here too!] | |
46 | */ | |
47 | static unsigned int last_irq_sums[NR_CPUS]; | |
48 | ||
49 | int __init check_watchdog(void) | |
50 | { | |
51 | irq_cpustat_t tmp[1]; | |
52 | ||
53 | printk(KERN_INFO "Testing Watchdog... "); | |
54 | ||
55 | memcpy(tmp, irq_stat, sizeof(tmp)); | |
56 | local_irq_enable(); | |
57 | mdelay((10 * 1000) / watchdog_hz); /* wait 10 ticks */ | |
58 | local_irq_disable(); | |
59 | ||
60 | if (nmi_count(0) - tmp[0].__nmi_count <= 5) { | |
61 | printk(KERN_WARNING "CPU#%d: Watchdog appears to be stuck!\n", | |
62 | 0); | |
63 | return -1; | |
64 | } | |
65 | ||
66 | printk(KERN_INFO "OK.\n"); | |
67 | ||
368dd5ac AT |
68 | /* now that we know it works we can reduce NMI frequency to something |
69 | * more reasonable; makes a difference in some configs | |
b920de1b DH |
70 | */ |
71 | watchdog_hz = 1; | |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
76 | static int __init setup_watchdog(char *str) | |
77 | { | |
78 | unsigned tmp; | |
79 | int opt; | |
80 | u8 ctr; | |
81 | ||
82 | get_option(&str, &opt); | |
83 | if (opt != 1) | |
84 | return 0; | |
85 | ||
86 | watchdog = opt; | |
87 | if (watchdog) { | |
88 | set_intr_stub(EXCEP_WDT, watchdog_handler); | |
89 | ctr = WDCTR_WDCK_65536th; | |
90 | WDCTR = WDCTR_WDRST | ctr; | |
91 | WDCTR = ctr; | |
92 | tmp = WDCTR; | |
93 | ||
94 | tmp = __muldiv64u(1 << (16 + ctr * 2), 1000000, MN10300_WDCLK); | |
95 | tmp = 1000000000 / tmp; | |
96 | watchdog_hz = (tmp + 500) / 1000; | |
97 | } | |
98 | ||
99 | return 1; | |
100 | } | |
101 | ||
102 | __setup("watchdog=", setup_watchdog); | |
103 | ||
104 | void __init watchdog_go(void) | |
105 | { | |
106 | u8 wdt; | |
107 | ||
108 | if (watchdog) { | |
109 | printk(KERN_INFO "Watchdog: running at %uHz\n", watchdog_hz); | |
110 | wdt = WDCTR & ~WDCTR_WDCNE; | |
111 | WDCTR = wdt | WDCTR_WDRST; | |
112 | wdt = WDCTR; | |
113 | WDCTR = wdt | WDCTR_WDCNE; | |
114 | wdt = WDCTR; | |
115 | ||
116 | check_watchdog(); | |
117 | } | |
118 | } | |
119 | ||
368dd5ac AT |
120 | #ifdef CONFIG_SMP |
121 | static void watchdog_dump_register(void *dummy) | |
122 | { | |
123 | printk(KERN_ERR "--- Register Dump (CPU%d) ---\n", CPUID); | |
7c7fcf76 | 124 | show_registers(current_frame()); |
368dd5ac AT |
125 | } |
126 | #endif | |
127 | ||
b920de1b DH |
128 | asmlinkage |
129 | void watchdog_interrupt(struct pt_regs *regs, enum exception_code excep) | |
130 | { | |
b920de1b DH |
131 | /* |
132 | * Since current-> is always on the stack, and we always switch | |
133 | * the stack NMI-atomically, it's safe to use smp_processor_id(). | |
134 | */ | |
368dd5ac | 135 | int sum, cpu; |
d2287f5e | 136 | int irq = NMIIRQ; |
b920de1b DH |
137 | u8 wdt, tmp; |
138 | ||
139 | wdt = WDCTR & ~WDCTR_WDCNE; | |
140 | WDCTR = wdt; | |
141 | tmp = WDCTR; | |
142 | NMICR = NMICR_WDIF; | |
143 | ||
368dd5ac | 144 | nmi_count(smp_processor_id())++; |
d2287f5e | 145 | kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); |
368dd5ac AT |
146 | |
147 | for_each_online_cpu(cpu) { | |
148 | ||
149 | sum = irq_stat[cpu].__irq_count; | |
150 | ||
151 | if ((last_irq_sums[cpu] == sum) | |
152 | #if defined(CONFIG_GDBSTUB) && defined(CONFIG_SMP) | |
153 | && !(CHK_GDBSTUB_BUSY() | |
154 | || atomic_read(&cpu_doing_single_step)) | |
155 | #endif | |
156 | ) { | |
b920de1b | 157 | /* |
368dd5ac AT |
158 | * Ayiee, looks like this CPU is stuck ... |
159 | * wait a few IRQs (5 seconds) before doing the oops ... | |
b920de1b | 160 | */ |
368dd5ac AT |
161 | watchdog_alert_counter[cpu]++; |
162 | if (watchdog_alert_counter[cpu] == 5 * watchdog_hz) { | |
163 | spin_lock(&watchdog_print_lock); | |
164 | /* | |
165 | * We are in trouble anyway, lets at least try | |
166 | * to get a message out. | |
167 | */ | |
168 | bust_spinlocks(1); | |
169 | printk(KERN_ERR | |
170 | "NMI Watchdog detected LOCKUP on CPU%d," | |
171 | " pc %08lx, registers:\n", | |
172 | cpu, regs->pc); | |
173 | #ifdef CONFIG_SMP | |
174 | printk(KERN_ERR | |
175 | "--- Register Dump (CPU%d) ---\n", | |
176 | CPUID); | |
177 | #endif | |
178 | show_registers(regs); | |
179 | #ifdef CONFIG_SMP | |
180 | smp_nmi_call_function(watchdog_dump_register, | |
181 | NULL, 1); | |
182 | #endif | |
183 | printk(KERN_NOTICE "console shuts up ...\n"); | |
184 | console_silent(); | |
185 | spin_unlock(&watchdog_print_lock); | |
186 | bust_spinlocks(0); | |
b920de1b | 187 | #ifdef CONFIG_GDBSTUB |
368dd5ac AT |
188 | if (CHK_GDBSTUB_BUSY_AND_ACTIVE()) |
189 | gdbstub_exception(regs, excep); | |
190 | else | |
191 | gdbstub_intercept(regs, excep); | |
b920de1b | 192 | #endif |
368dd5ac AT |
193 | do_exit(SIGSEGV); |
194 | } | |
195 | } else { | |
196 | last_irq_sums[cpu] = sum; | |
197 | watchdog_alert_counter[cpu] = 0; | |
b920de1b | 198 | } |
b920de1b DH |
199 | } |
200 | ||
201 | WDCTR = wdt | WDCTR_WDRST; | |
202 | tmp = WDCTR; | |
203 | WDCTR = wdt | WDCTR_WDCNE; | |
204 | tmp = WDCTR; | |
205 | } |