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authorThomas Gleixner <tglx@linutronix.de>2007-05-09 05:35:15 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 15:30:56 -0400
commitb52f52a093bb1e841e014c2087b5bee7162da413 (patch)
tree7b7135897195fc9d14473d3ab824d59a4b65e5ad /kernel/time/clocksource.c
parent4037d452202e34214e8a939fa5621b2b3bbb45b7 (diff)
clocksource: fix resume logic
We need to make sure that the clocksources are resumed, when timekeeping is resumed. The current resume logic does not guarantee this. Add a resume function pointer to the clocksource struct, so clocksource drivers which need to reinitialize the clocksource can provide a resume function. Add a resume function, which calls the maybe available clocksource resume functions and resets the watchdog function, so a stable TSC can be used accross suspend/resume. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/time/clocksource.c')
-rw-r--r--kernel/time/clocksource.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index db0c725de5ea..3db5c3c460d7 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -74,6 +74,8 @@ static struct clocksource *watchdog;
74static struct timer_list watchdog_timer; 74static struct timer_list watchdog_timer;
75static DEFINE_SPINLOCK(watchdog_lock); 75static DEFINE_SPINLOCK(watchdog_lock);
76static cycle_t watchdog_last; 76static cycle_t watchdog_last;
77static int watchdog_resumed;
78
77/* 79/*
78 * Interval: 0.5sec Threshold: 0.0625s 80 * Interval: 0.5sec Threshold: 0.0625s
79 */ 81 */
@@ -98,15 +100,26 @@ static void clocksource_watchdog(unsigned long data)
98 struct clocksource *cs, *tmp; 100 struct clocksource *cs, *tmp;
99 cycle_t csnow, wdnow; 101 cycle_t csnow, wdnow;
100 int64_t wd_nsec, cs_nsec; 102 int64_t wd_nsec, cs_nsec;
103 int resumed;
101 104
102 spin_lock(&watchdog_lock); 105 spin_lock(&watchdog_lock);
103 106
107 resumed = watchdog_resumed;
108 if (unlikely(resumed))
109 watchdog_resumed = 0;
110
104 wdnow = watchdog->read(); 111 wdnow = watchdog->read();
105 wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask); 112 wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
106 watchdog_last = wdnow; 113 watchdog_last = wdnow;
107 114
108 list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) { 115 list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
109 csnow = cs->read(); 116 csnow = cs->read();
117
118 if (unlikely(resumed)) {
119 cs->wd_last = csnow;
120 continue;
121 }
122
110 /* Initialized ? */ 123 /* Initialized ? */
111 if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) { 124 if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
112 if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && 125 if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
@@ -136,6 +149,13 @@ static void clocksource_watchdog(unsigned long data)
136 } 149 }
137 spin_unlock(&watchdog_lock); 150 spin_unlock(&watchdog_lock);
138} 151}
152static void clocksource_resume_watchdog(void)
153{
154 spin_lock(&watchdog_lock);
155 watchdog_resumed = 1;
156 spin_unlock(&watchdog_lock);
157}
158
139static void clocksource_check_watchdog(struct clocksource *cs) 159static void clocksource_check_watchdog(struct clocksource *cs)
140{ 160{
141 struct clocksource *cse; 161 struct clocksource *cse;
@@ -182,9 +202,34 @@ static void clocksource_check_watchdog(struct clocksource *cs)
182 if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) 202 if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
183 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; 203 cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
184} 204}
205
206static inline void clocksource_resume_watchdog(void) { }
185#endif 207#endif
186 208
187/** 209/**
210 * clocksource_resume - resume the clocksource(s)
211 */
212void clocksource_resume(void)
213{
214 struct list_head *tmp;
215 unsigned long flags;
216
217 spin_lock_irqsave(&clocksource_lock, flags);
218
219 list_for_each(tmp, &clocksource_list) {
220 struct clocksource *cs;
221
222 cs = list_entry(tmp, struct clocksource, list);
223 if (cs->resume)
224 cs->resume();
225 }
226
227 clocksource_resume_watchdog();
228
229 spin_unlock_irqrestore(&clocksource_lock, flags);
230}
231
232/**
188 * clocksource_get_next - Returns the selected clocksource 233 * clocksource_get_next - Returns the selected clocksource
189 * 234 *
190 */ 235 */