From 1f2aab01ba2f6c591dee93daf4b57fd9785f3b41 Mon Sep 17 00:00:00 2001 From: Greg Ungerer Date: Wed, 16 Nov 2011 15:09:02 +1000 Subject: [PATCH] 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 Signed-off-by: Greg Ungerer --- arch/m68k/platform/coldfire/sltimers.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/m68k/platform/coldfire/sltimers.c b/arch/m68k/platform/coldfire/sltimers.c index b7f822b552bb..54e1452f853a 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 = { -- 2.34.1