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> | |
21 | #include <asm/system.h> | |
60063497 | 22 | #include <linux/atomic.h> |
b920de1b DH |
23 | #include <asm/intctl-regs.h> |
24 | #include <asm/rtc-regs.h> | |
25 | #include <asm/div64.h> | |
26 | #include <asm/smp.h> | |
27 | #include <asm/gdb-stub.h> | |
2f2a2132 | 28 | #include <proc/clock.h> |
b920de1b DH |
29 | |
30 | static DEFINE_SPINLOCK(watchdog_print_lock); | |
31 | static unsigned int watchdog; | |
32 | static unsigned int watchdog_hz = 1; | |
368dd5ac | 33 | unsigned int watchdog_alert_counter[NR_CPUS]; |
b920de1b DH |
34 | |
35 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
36 | ||
37 | /* | |
38 | * the best way to detect whether a CPU has a 'hard lockup' problem | |
39 | * is to check its timer makes IRQ counts. If they are not | |
40 | * changing then that CPU has some problem. | |
41 | * | |
b920de1b DH |
42 | * since NMIs dont listen to _any_ locks, we have to be extremely |
43 | * careful not to rely on unsafe variables. The printk might lock | |
44 | * up though, so we have to break up any console locks first ... | |
45 | * [when there will be more tty-related locks, break them up | |
46 | * here too!] | |
47 | */ | |
48 | static unsigned int last_irq_sums[NR_CPUS]; | |
49 | ||
50 | int __init check_watchdog(void) | |
51 | { | |
52 | irq_cpustat_t tmp[1]; | |
53 | ||
54 | printk(KERN_INFO "Testing Watchdog... "); | |
55 | ||
56 | memcpy(tmp, irq_stat, sizeof(tmp)); | |
57 | local_irq_enable(); | |
58 | mdelay((10 * 1000) / watchdog_hz); /* wait 10 ticks */ | |
59 | local_irq_disable(); | |
60 | ||
61 | if (nmi_count(0) - tmp[0].__nmi_count <= 5) { | |
62 | printk(KERN_WARNING "CPU#%d: Watchdog appears to be stuck!\n", | |
63 | 0); | |
64 | return -1; | |
65 | } | |
66 | ||
67 | printk(KERN_INFO "OK.\n"); | |
68 | ||
368dd5ac AT |
69 | /* now that we know it works we can reduce NMI frequency to something |
70 | * more reasonable; makes a difference in some configs | |
b920de1b DH |
71 | */ |
72 | watchdog_hz = 1; | |
73 | ||
74 | return 0; | |
75 | } | |
76 | ||
77 | static int __init setup_watchdog(char *str) | |
78 | { | |
79 | unsigned tmp; | |
80 | int opt; | |
81 | u8 ctr; | |
82 | ||
83 | get_option(&str, &opt); | |
84 | if (opt != 1) | |
85 | return 0; | |
86 | ||
87 | watchdog = opt; | |
88 | if (watchdog) { | |
89 | set_intr_stub(EXCEP_WDT, watchdog_handler); | |
90 | ctr = WDCTR_WDCK_65536th; | |
91 | WDCTR = WDCTR_WDRST | ctr; | |
92 | WDCTR = ctr; | |
93 | tmp = WDCTR; | |
94 | ||
95 | tmp = __muldiv64u(1 << (16 + ctr * 2), 1000000, MN10300_WDCLK); | |
96 | tmp = 1000000000 / tmp; | |
97 | watchdog_hz = (tmp + 500) / 1000; | |
98 | } | |
99 | ||
100 | return 1; | |
101 | } | |
102 | ||
103 | __setup("watchdog=", setup_watchdog); | |
104 | ||
105 | void __init watchdog_go(void) | |
106 | { | |
107 | u8 wdt; | |
108 | ||
109 | if (watchdog) { | |
110 | printk(KERN_INFO "Watchdog: running at %uHz\n", watchdog_hz); | |
111 | wdt = WDCTR & ~WDCTR_WDCNE; | |
112 | WDCTR = wdt | WDCTR_WDRST; | |
113 | wdt = WDCTR; | |
114 | WDCTR = wdt | WDCTR_WDCNE; | |
115 | wdt = WDCTR; | |
116 | ||
117 | check_watchdog(); | |
118 | } | |
119 | } | |
120 | ||
368dd5ac AT |
121 | #ifdef CONFIG_SMP |
122 | static void watchdog_dump_register(void *dummy) | |
123 | { | |
124 | printk(KERN_ERR "--- Register Dump (CPU%d) ---\n", CPUID); | |
7c7fcf76 | 125 | show_registers(current_frame()); |
368dd5ac AT |
126 | } |
127 | #endif | |
128 | ||
b920de1b DH |
129 | asmlinkage |
130 | void watchdog_interrupt(struct pt_regs *regs, enum exception_code excep) | |
131 | { | |
b920de1b DH |
132 | /* |
133 | * Since current-> is always on the stack, and we always switch | |
134 | * the stack NMI-atomically, it's safe to use smp_processor_id(). | |
135 | */ | |
368dd5ac | 136 | int sum, cpu; |
d2287f5e | 137 | int irq = NMIIRQ; |
b920de1b DH |
138 | u8 wdt, tmp; |
139 | ||
140 | wdt = WDCTR & ~WDCTR_WDCNE; | |
141 | WDCTR = wdt; | |
142 | tmp = WDCTR; | |
143 | NMICR = NMICR_WDIF; | |
144 | ||
368dd5ac | 145 | nmi_count(smp_processor_id())++; |
d2287f5e | 146 | kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); |
368dd5ac AT |
147 | |
148 | for_each_online_cpu(cpu) { | |
149 | ||
150 | sum = irq_stat[cpu].__irq_count; | |
151 | ||
152 | if ((last_irq_sums[cpu] == sum) | |
153 | #if defined(CONFIG_GDBSTUB) && defined(CONFIG_SMP) | |
154 | && !(CHK_GDBSTUB_BUSY() | |
155 | || atomic_read(&cpu_doing_single_step)) | |
156 | #endif | |
157 | ) { | |
b920de1b | 158 | /* |
368dd5ac AT |
159 | * Ayiee, looks like this CPU is stuck ... |
160 | * wait a few IRQs (5 seconds) before doing the oops ... | |
b920de1b | 161 | */ |
368dd5ac AT |
162 | watchdog_alert_counter[cpu]++; |
163 | if (watchdog_alert_counter[cpu] == 5 * watchdog_hz) { | |
164 | spin_lock(&watchdog_print_lock); | |
165 | /* | |
166 | * We are in trouble anyway, lets at least try | |
167 | * to get a message out. | |
168 | */ | |
169 | bust_spinlocks(1); | |
170 | printk(KERN_ERR | |
171 | "NMI Watchdog detected LOCKUP on CPU%d," | |
172 | " pc %08lx, registers:\n", | |
173 | cpu, regs->pc); | |
174 | #ifdef CONFIG_SMP | |
175 | printk(KERN_ERR | |
176 | "--- Register Dump (CPU%d) ---\n", | |
177 | CPUID); | |
178 | #endif | |
179 | show_registers(regs); | |
180 | #ifdef CONFIG_SMP | |
181 | smp_nmi_call_function(watchdog_dump_register, | |
182 | NULL, 1); | |
183 | #endif | |
184 | printk(KERN_NOTICE "console shuts up ...\n"); | |
185 | console_silent(); | |
186 | spin_unlock(&watchdog_print_lock); | |
187 | bust_spinlocks(0); | |
b920de1b | 188 | #ifdef CONFIG_GDBSTUB |
368dd5ac AT |
189 | if (CHK_GDBSTUB_BUSY_AND_ACTIVE()) |
190 | gdbstub_exception(regs, excep); | |
191 | else | |
192 | gdbstub_intercept(regs, excep); | |
b920de1b | 193 | #endif |
368dd5ac AT |
194 | do_exit(SIGSEGV); |
195 | } | |
196 | } else { | |
197 | last_irq_sums[cpu] = sum; | |
198 | watchdog_alert_counter[cpu] = 0; | |
b920de1b | 199 | } |
b920de1b DH |
200 | } |
201 | ||
202 | WDCTR = wdt | WDCTR_WDRST; | |
203 | tmp = WDCTR; | |
204 | WDCTR = wdt | WDCTR_WDCNE; | |
205 | tmp = WDCTR; | |
206 | } |