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authorjohn stultz <johnstul@us.ibm.com>2009-09-21 20:04:04 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:17:43 -0400
commit95ad759c6b0f30ad9aa5efbdbcecb9597238c00f (patch)
tree596e961f86340694d205b652de02c90a16546b90 /arch/m32r
parentd5a6d1739526ed8c383db3dabc232bc15603439a (diff)
m32r: convert to use arch_gettimeoffset()
Convert m32r to use GENERIC_TIME via the arch_getoffset() infrastructure, reducing the amount of arch specific code we need to maintain. I also noted that m32r doesn't seem to be taking the xtime write lock before calling do_timer()! That looks like a pretty bad bug to me. If folks agree, let me know and I can move the lock grab to the correct spot. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/m32r')
-rw-r--r--arch/m32r/Kconfig6
-rw-r--r--arch/m32r/kernel/time.c74
2 files changed, 9 insertions, 71 deletions
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index cabba332cc48..c41234f1b825 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -41,6 +41,12 @@ config HZ
41 int 41 int
42 default 100 42 default 100
43 43
44config GENERIC_TIME
45 def_bool y
46
47config ARCH_USES_GETTIMEOFFSET
48 def_bool y
49
44source "init/Kconfig" 50source "init/Kconfig"
45 51
46source "kernel/Kconfig.freezer" 52source "kernel/Kconfig.freezer"
diff --git a/arch/m32r/kernel/time.c b/arch/m32r/kernel/time.c
index cada3ba4b990..ba61c4c73202 100644
--- a/arch/m32r/kernel/time.c
+++ b/arch/m32r/kernel/time.c
@@ -48,7 +48,7 @@ extern void smp_local_timer_interrupt(void);
48 48
49static unsigned long latch; 49static unsigned long latch;
50 50
51static unsigned long do_gettimeoffset(void) 51u32 arch_gettimeoffset(void)
52{ 52{
53 unsigned long elapsed_time = 0; /* [us] */ 53 unsigned long elapsed_time = 0; /* [us] */
54 54
@@ -93,79 +93,10 @@ static unsigned long do_gettimeoffset(void)
93#error no chip configuration 93#error no chip configuration
94#endif 94#endif
95 95
96 return elapsed_time; 96 return elapsed_time * 1000;
97} 97}
98 98
99/* 99/*
100 * This version of gettimeofday has near microsecond resolution.
101 */
102void do_gettimeofday(struct timeval *tv)
103{
104 unsigned long seq;
105 unsigned long usec, sec;
106 unsigned long max_ntp_tick = tick_usec - tickadj;
107
108 do {
109 seq = read_seqbegin(&xtime_lock);
110
111 usec = do_gettimeoffset();
112
113 /*
114 * If time_adjust is negative then NTP is slowing the clock
115 * so make sure not to go into next possible interval.
116 * Better to lose some accuracy than have time go backwards..
117 */
118 if (unlikely(time_adjust < 0))
119 usec = min(usec, max_ntp_tick);
120
121 sec = xtime.tv_sec;
122 usec += (xtime.tv_nsec / 1000);
123 } while (read_seqretry(&xtime_lock, seq));
124
125 while (usec >= 1000000) {
126 usec -= 1000000;
127 sec++;
128 }
129
130 tv->tv_sec = sec;
131 tv->tv_usec = usec;
132}
133
134EXPORT_SYMBOL(do_gettimeofday);
135
136int do_settimeofday(struct timespec *tv)
137{
138 time_t wtm_sec, sec = tv->tv_sec;
139 long wtm_nsec, nsec = tv->tv_nsec;
140
141 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
142 return -EINVAL;
143
144 write_seqlock_irq(&xtime_lock);
145 /*
146 * This is revolting. We need to set "xtime" correctly. However, the
147 * value in this location is the value at the most recent update of
148 * wall time. Discover what correction gettimeofday() would have
149 * made, and then undo it!
150 */
151 nsec -= do_gettimeoffset() * NSEC_PER_USEC;
152
153 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
154 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
155
156 set_normalized_timespec(&xtime, sec, nsec);
157 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
158
159 ntp_clear();
160 write_sequnlock_irq(&xtime_lock);
161 clock_was_set();
162
163 return 0;
164}
165
166EXPORT_SYMBOL(do_settimeofday);
167
168/*
169 * In order to set the CMOS clock precisely, set_rtc_mmss has to be 100 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
170 * called 500 ms after the second nowtime has started, because when 101 * called 500 ms after the second nowtime has started, because when
171 * nowtime is written into the registers of the CMOS clock, it will 102 * nowtime is written into the registers of the CMOS clock, it will
@@ -192,6 +123,7 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
192#ifndef CONFIG_SMP 123#ifndef CONFIG_SMP
193 profile_tick(CPU_PROFILING); 124 profile_tick(CPU_PROFILING);
194#endif 125#endif
126 /* XXX FIXME. Uh, the xtime_lock should be held here, no? */
195 do_timer(1); 127 do_timer(1);
196 128
197#ifndef CONFIG_SMP 129#ifndef CONFIG_SMP