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authorNicolas Pitre <nico@cam.org>2005-09-01 07:48:47 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-09-01 07:48:47 -0400
commit20e912680842504ab4633deaa644c2b855ad3d44 (patch)
treeb92a5c0c287c9a115a43b85f55a818996df5e319
parent5c53ff088cb76dca52bdf2ef36ea63147763f9ea (diff)
[ARM] 2863/1: clarify comment in PXA2xx and SA1x00 timer code
Patch from Nicolas Pitre Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/mach-pxa/time.c7
-rw-r--r--arch/arm/mach-sa1100/time.c17
2 files changed, 12 insertions, 12 deletions
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index 72b15e9a373a..7dad3f1465e0 100644
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -91,9 +91,10 @@ pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
91 91
92 /* Loop until we get ahead of the free running timer. 92 /* Loop until we get ahead of the free running timer.
93 * This ensures an exact clock tick count and time accuracy. 93 * This ensures an exact clock tick count and time accuracy.
94 * IRQs are disabled inside the loop to ensure coherence between 94 * Since IRQs are disabled at this point, coherence between
95 * lost_ticks (updated in do_timer()) and the match reg value, so we 95 * lost_ticks(updated in do_timer()) and the match reg value is
96 * can use do_gettimeofday() from interrupt handlers. 96 * ensured, hence we can use do_gettimeofday() from interrupt
97 * handlers.
97 * 98 *
98 * HACK ALERT: it seems that the PXA timer regs aren't updated right 99 * HACK ALERT: it seems that the PXA timer regs aren't updated right
99 * away in all cases when a write occurs. We therefore compare with 100 * away in all cases when a write occurs. We therefore compare with
diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c
index 0eeb3616ffea..a084b38698cf 100644
--- a/arch/arm/mach-sa1100/time.c
+++ b/arch/arm/mach-sa1100/time.c
@@ -70,15 +70,6 @@ static unsigned long sa1100_gettimeoffset (void)
70 return usec; 70 return usec;
71} 71}
72 72
73/*
74 * We will be entered with IRQs enabled.
75 *
76 * Loop until we get ahead of the free running timer.
77 * This ensures an exact clock tick count and time accuracy.
78 * IRQs are disabled inside the loop to ensure coherence between
79 * lost_ticks (updated in do_timer()) and the match reg value, so we
80 * can use do_gettimeofday() from interrupt handlers.
81 */
82static irqreturn_t 73static irqreturn_t
83sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) 74sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
84{ 75{
@@ -86,6 +77,14 @@ sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
86 77
87 write_seqlock(&xtime_lock); 78 write_seqlock(&xtime_lock);
88 79
80 /*
81 * Loop until we get ahead of the free running timer.
82 * This ensures an exact clock tick count and time accuracy.
83 * Since IRQs are disabled at this point, coherence between
84 * lost_ticks(updated in do_timer()) and the match reg value is
85 * ensured, hence we can use do_gettimeofday() from interrupt
86 * handlers.
87 */
89 do { 88 do {
90 timer_tick(regs); 89 timer_tick(regs);
91 OSSR = OSSR_M0; /* Clear match on timer 0 */ 90 OSSR = OSSR_M0; /* Clear match on timer 0 */