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authorGreg Ungerer <gerg@uclinux.org>2011-11-16 15:09:02 +1000
committerGreg Ungerer <gerg@uclinux.org>2011-12-24 21:47:58 +1000
commit1f2aab01ba2f6c591dee93daf4b57fd9785f3b41 (patch)
tree78f44c9a87f8664fcdf1569be87a89efe0bfe9ea /arch/m68k/platform/coldfire
parentec84118795fa687192de04e0dcb63178e4bf63e5 (diff)
m68knommu: fix broken ColdFire slice timer read_clk() code
There is a race on reading the ColdFire slice timer current count and the total clock count so far. Interrupts are off, and we may have just missed getting a new timer wrap event interrupt. Check for this and adjust the cycle count and current read count accordingly. Also the slice timer counts down from the terminal count. So in read_clk() we need take the current clock count away from the terminal count. Reported-by: Alexander Stein <alexander.stein@systec-electronic.com> Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Diffstat (limited to 'arch/m68k/platform/coldfire')
-rw-r--r--arch/m68k/platform/coldfire/sltimers.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/m68k/platform/coldfire/sltimers.c b/arch/m68k/platform/coldfire/sltimers.c
index b7f822b552b..54e1452f853 100644
--- a/arch/m68k/platform/coldfire/sltimers.c
+++ b/arch/m68k/platform/coldfire/sltimers.c
@@ -98,16 +98,19 @@ static struct irqaction mcfslt_timer_irq = {
static cycle_t mcfslt_read_clk(struct clocksource *cs)
{
unsigned long flags;
- u32 cycles;
- u16 scnt;
+ u32 cycles, scnt;
local_irq_save(flags);
scnt = __raw_readl(TA(MCFSLT_SCNT));
cycles = mcfslt_cnt;
+ if (__raw_readl(TA(MCFSLT_SSR)) & MCFSLT_SSR_TE) {
+ cycles += mcfslt_cycles_per_jiffy;
+ scnt = __raw_readl(TA(MCFSLT_SCNT));
+ }
local_irq_restore(flags);
/* subtract because slice timers count down */
- return cycles - scnt;
+ return cycles + ((mcfslt_cycles_per_jiffy - 1) - scnt);
}
static struct clocksource mcfslt_clk = {