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60ffdb36 GY |
1 | /* |
2 | * Blackfin nmi_watchdog Driver | |
3 | * | |
4 | * Originally based on bfin_wdt.c | |
5 | * Copyright 2010-2010 Analog Devices Inc. | |
6 | * Graff Yang <graf.yang@analog.com> | |
7 | * | |
8 | * Enter bugs at http://blackfin.uclinux.org/ | |
9 | * | |
10 | * Licensed under the GPL-2 or later. | |
11 | */ | |
12 | ||
13 | #include <linux/bitops.h> | |
14 | #include <linux/hardirq.h> | |
15 | #include <linux/sysdev.h> | |
16 | #include <linux/pm.h> | |
17 | #include <linux/nmi.h> | |
18 | #include <linux/smp.h> | |
19 | #include <linux/timer.h> | |
20 | #include <asm/blackfin.h> | |
21 | #include <asm/atomic.h> | |
22 | #include <asm/cacheflush.h> | |
64b33a00 | 23 | #include <asm/bfin_watchdog.h> |
60ffdb36 GY |
24 | |
25 | #define DRV_NAME "nmi-wdt" | |
26 | ||
27 | #define NMI_WDT_TIMEOUT 5 /* 5 seconds */ | |
28 | #define NMI_CHECK_TIMEOUT (4 * HZ) /* 4 seconds in jiffies */ | |
29 | static int nmi_wdt_cpu = 1; | |
30 | ||
31 | static unsigned int timeout = NMI_WDT_TIMEOUT; | |
32 | static int nmi_active; | |
33 | ||
34 | static unsigned short wdoga_ctl; | |
35 | static unsigned int wdoga_cnt; | |
36 | static struct corelock_slot saved_corelock; | |
37 | static atomic_t nmi_touched[NR_CPUS]; | |
38 | static struct timer_list ntimer; | |
39 | ||
40 | enum { | |
41 | COREA_ENTER_NMI = 0, | |
42 | COREA_EXIT_NMI, | |
43 | COREB_EXIT_NMI, | |
44 | ||
45 | NMI_EVENT_NR, | |
46 | }; | |
47 | static unsigned long nmi_event __attribute__ ((__section__(".l2.bss"))); | |
48 | ||
49 | /* we are in nmi, non-atomic bit ops is safe */ | |
50 | static inline void set_nmi_event(int event) | |
51 | { | |
52 | __set_bit(event, &nmi_event); | |
53 | } | |
54 | ||
55 | static inline void wait_nmi_event(int event) | |
56 | { | |
57 | while (!test_bit(event, &nmi_event)) | |
58 | barrier(); | |
59 | __clear_bit(event, &nmi_event); | |
60 | } | |
61 | ||
62 | static inline void send_corea_nmi(void) | |
63 | { | |
64 | wdoga_ctl = bfin_read_WDOGA_CTL(); | |
65 | wdoga_cnt = bfin_read_WDOGA_CNT(); | |
66 | ||
67 | bfin_write_WDOGA_CTL(WDEN_DISABLE); | |
68 | bfin_write_WDOGA_CNT(0); | |
69 | bfin_write_WDOGA_CTL(WDEN_ENABLE | ICTL_NMI); | |
70 | } | |
71 | ||
72 | static inline void restore_corea_nmi(void) | |
73 | { | |
74 | bfin_write_WDOGA_CTL(WDEN_DISABLE); | |
75 | bfin_write_WDOGA_CTL(WDOG_EXPIRED | WDEN_DISABLE | ICTL_NONE); | |
76 | ||
77 | bfin_write_WDOGA_CNT(wdoga_cnt); | |
78 | bfin_write_WDOGA_CTL(wdoga_ctl); | |
79 | } | |
80 | ||
81 | static inline void save_corelock(void) | |
82 | { | |
83 | saved_corelock = corelock; | |
84 | corelock.lock = 0; | |
85 | } | |
86 | ||
87 | static inline void restore_corelock(void) | |
88 | { | |
89 | corelock = saved_corelock; | |
90 | } | |
91 | ||
92 | ||
93 | static inline void nmi_wdt_keepalive(void) | |
94 | { | |
95 | bfin_write_WDOGB_STAT(0); | |
96 | } | |
97 | ||
98 | static inline void nmi_wdt_stop(void) | |
99 | { | |
100 | bfin_write_WDOGB_CTL(WDEN_DISABLE); | |
101 | } | |
102 | ||
103 | /* before calling this function, you must stop the WDT */ | |
104 | static inline void nmi_wdt_clear(void) | |
105 | { | |
106 | /* clear TRO bit, disable event generation */ | |
107 | bfin_write_WDOGB_CTL(WDOG_EXPIRED | WDEN_DISABLE | ICTL_NONE); | |
108 | } | |
109 | ||
110 | static inline void nmi_wdt_start(void) | |
111 | { | |
112 | bfin_write_WDOGB_CTL(WDEN_ENABLE | ICTL_NMI); | |
113 | } | |
114 | ||
115 | static inline int nmi_wdt_running(void) | |
116 | { | |
117 | return ((bfin_read_WDOGB_CTL() & WDEN_MASK) != WDEN_DISABLE); | |
118 | } | |
119 | ||
120 | static inline int nmi_wdt_set_timeout(unsigned long t) | |
121 | { | |
122 | u32 cnt, max_t, sclk; | |
123 | int run; | |
124 | ||
125 | sclk = get_sclk(); | |
126 | max_t = -1 / sclk; | |
127 | cnt = t * sclk; | |
128 | if (t > max_t) { | |
129 | pr_warning("NMI: timeout value is too large\n"); | |
130 | return -EINVAL; | |
131 | } | |
132 | ||
133 | run = nmi_wdt_running(); | |
134 | nmi_wdt_stop(); | |
135 | bfin_write_WDOGB_CNT(cnt); | |
136 | if (run) | |
137 | nmi_wdt_start(); | |
138 | ||
139 | timeout = t; | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | int check_nmi_wdt_touched(void) | |
145 | { | |
146 | unsigned int this_cpu = smp_processor_id(); | |
147 | unsigned int cpu; | |
148 | ||
149 | cpumask_t mask = cpu_online_map; | |
150 | ||
151 | if (!atomic_read(&nmi_touched[this_cpu])) | |
152 | return 0; | |
153 | ||
154 | atomic_set(&nmi_touched[this_cpu], 0); | |
155 | ||
156 | cpu_clear(this_cpu, mask); | |
157 | for_each_cpu_mask(cpu, mask) { | |
158 | invalidate_dcache_range((unsigned long)(&nmi_touched[cpu]), | |
159 | (unsigned long)(&nmi_touched[cpu])); | |
160 | if (!atomic_read(&nmi_touched[cpu])) | |
161 | return 0; | |
162 | atomic_set(&nmi_touched[cpu], 0); | |
163 | } | |
164 | ||
165 | return 1; | |
166 | } | |
167 | ||
168 | static void nmi_wdt_timer(unsigned long data) | |
169 | { | |
170 | if (check_nmi_wdt_touched()) | |
171 | nmi_wdt_keepalive(); | |
172 | ||
173 | mod_timer(&ntimer, jiffies + NMI_CHECK_TIMEOUT); | |
174 | } | |
175 | ||
176 | static int __init init_nmi_wdt(void) | |
177 | { | |
178 | nmi_wdt_set_timeout(timeout); | |
179 | nmi_wdt_start(); | |
180 | nmi_active = true; | |
181 | ||
182 | init_timer(&ntimer); | |
183 | ntimer.function = nmi_wdt_timer; | |
184 | ntimer.expires = jiffies + NMI_CHECK_TIMEOUT; | |
185 | add_timer(&ntimer); | |
186 | ||
187 | pr_info("nmi_wdt: initialized: timeout=%d sec\n", timeout); | |
188 | return 0; | |
189 | } | |
190 | device_initcall(init_nmi_wdt); | |
191 | ||
192 | void touch_nmi_watchdog(void) | |
193 | { | |
194 | atomic_set(&nmi_touched[smp_processor_id()], 1); | |
195 | } | |
196 | ||
197 | /* Suspend/resume support */ | |
198 | #ifdef CONFIG_PM | |
199 | static int nmi_wdt_suspend(struct sys_device *dev, pm_message_t state) | |
200 | { | |
201 | nmi_wdt_stop(); | |
202 | return 0; | |
203 | } | |
204 | ||
205 | static int nmi_wdt_resume(struct sys_device *dev) | |
206 | { | |
207 | if (nmi_active) | |
208 | nmi_wdt_start(); | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static struct sysdev_class nmi_sysclass = { | |
213 | .name = DRV_NAME, | |
214 | .resume = nmi_wdt_resume, | |
215 | .suspend = nmi_wdt_suspend, | |
216 | }; | |
217 | ||
218 | static struct sys_device device_nmi_wdt = { | |
219 | .id = 0, | |
220 | .cls = &nmi_sysclass, | |
221 | }; | |
222 | ||
223 | static int __init init_nmi_wdt_sysfs(void) | |
224 | { | |
225 | int error; | |
226 | ||
227 | if (!nmi_active) | |
228 | return 0; | |
229 | ||
230 | error = sysdev_class_register(&nmi_sysclass); | |
231 | if (!error) | |
232 | error = sysdev_register(&device_nmi_wdt); | |
233 | return error; | |
234 | } | |
235 | late_initcall(init_nmi_wdt_sysfs); | |
236 | ||
237 | #endif /* CONFIG_PM */ | |
238 | ||
239 | ||
240 | asmlinkage notrace void do_nmi(struct pt_regs *fp) | |
241 | { | |
242 | unsigned int cpu = smp_processor_id(); | |
243 | nmi_enter(); | |
244 | ||
245 | cpu_pda[cpu].__nmi_count += 1; | |
246 | ||
247 | if (cpu == nmi_wdt_cpu) { | |
248 | /* CoreB goes here first */ | |
249 | ||
250 | /* reload the WDOG_STAT */ | |
251 | nmi_wdt_keepalive(); | |
252 | ||
253 | /* clear nmi interrupt for CoreB */ | |
254 | nmi_wdt_stop(); | |
255 | nmi_wdt_clear(); | |
256 | ||
257 | /* trigger NMI interrupt of CoreA */ | |
258 | send_corea_nmi(); | |
259 | ||
260 | /* waiting CoreB to enter NMI */ | |
261 | wait_nmi_event(COREA_ENTER_NMI); | |
262 | ||
263 | /* recover WDOGA's settings */ | |
264 | restore_corea_nmi(); | |
265 | ||
266 | save_corelock(); | |
267 | ||
268 | /* corelock is save/cleared, CoreA is dummping messages */ | |
269 | ||
270 | wait_nmi_event(COREA_EXIT_NMI); | |
271 | } else { | |
272 | /* OK, CoreA entered NMI */ | |
273 | set_nmi_event(COREA_ENTER_NMI); | |
274 | } | |
275 | ||
276 | pr_emerg("\nNMI Watchdog detected LOCKUP, dump for CPU %d\n", cpu); | |
277 | dump_bfin_process(fp); | |
278 | dump_bfin_mem(fp); | |
279 | show_regs(fp); | |
280 | dump_bfin_trace_buffer(); | |
281 | show_stack(current, (unsigned long *)fp); | |
282 | ||
283 | if (cpu == nmi_wdt_cpu) { | |
284 | pr_emerg("This fault is not recoverable, sorry!\n"); | |
285 | ||
286 | /* CoreA dump finished, restore the corelock */ | |
287 | restore_corelock(); | |
288 | ||
289 | set_nmi_event(COREB_EXIT_NMI); | |
290 | } else { | |
291 | /* CoreB dump finished, notice the CoreA we are done */ | |
292 | set_nmi_event(COREA_EXIT_NMI); | |
293 | ||
294 | /* synchronize with CoreA */ | |
295 | wait_nmi_event(COREB_EXIT_NMI); | |
296 | } | |
297 | ||
298 | nmi_exit(); | |
299 | } |