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ARM: msm: Wait for timer clear to complete

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Without looping on the status bit, there is no way to guarantee
that a clear of the timer has actually completed. This can cause
us to enable the timer before the count has cleared and miss a
timer interrupt. To simplify this patch, remove the timer
register setup done during timer init, since it's duplicate work
that is eventually done in the set_next_event() callback.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
This commit is contained in:
Stephen Boyd 2013-03-14 20:31:39 -07:00 committed by David Brown
parent eebdb0c1e1
commit e25e3d1fef
1 changed files with 23 additions and 18 deletions
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41
arch/arm/mach-msm/timer.c
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@ -30,20 +30,22 @@
#include "common.h"
#define TIMER_MATCH_VAL 0x0000
#define TIMER_COUNT_VAL 0x0004
#define TIMER_ENABLE 0x0008
#define TIMER_ENABLE_CLR_ON_MATCH_EN BIT(1)
#define TIMER_ENABLE_EN BIT(0)
#define TIMER_CLEAR 0x000C
#define DGT_CLK_CTL 0x10
#define DGT_CLK_CTL_DIV_4 0x3
#define TIMER_MATCH_VAL 0x0000
#define TIMER_COUNT_VAL 0x0004
#define TIMER_ENABLE 0x0008
#define TIMER_ENABLE_CLR_ON_MATCH_EN BIT(1)
#define TIMER_ENABLE_EN BIT(0)
#define TIMER_CLEAR 0x000C
#define DGT_CLK_CTL 0x10
#define DGT_CLK_CTL_DIV_4 0x3
#define TIMER_STS_GPT0_CLR_PEND BIT(10)
#define GPT_HZ 32768
#define MSM_DGT_SHIFT 5
static void __iomem *event_base;
static void __iomem *sts_base;
static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
{
@ -65,6 +67,11 @@ static int msm_timer_set_next_event(unsigned long cycles,
writel_relaxed(0, event_base + TIMER_CLEAR);
writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);
if (sts_base)
while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND)
cpu_relax();
writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
return 0;
}
@ -135,9 +142,6 @@ static int __cpuinit msm_local_timer_setup(struct clock_event_device *evt)
if (!smp_processor_id())
return 0;
writel_relaxed(0, event_base + TIMER_ENABLE);
writel_relaxed(0, event_base + TIMER_CLEAR);
writel_relaxed(~0, event_base + TIMER_MATCH_VAL);
evt->irq = msm_clockevent.irq;
evt->name = "local_timer";
evt->features = msm_clockevent.features;
@ -175,9 +179,6 @@ static void __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
struct clocksource *cs = &msm_clocksource;
int res;
writel_relaxed(0, event_base + TIMER_ENABLE);
writel_relaxed(0, event_base + TIMER_CLEAR);
writel_relaxed(~0, event_base + TIMER_MATCH_VAL);
ce->cpumask = cpumask_of(0);
ce->irq = irq;
@ -272,6 +273,7 @@ void __init msm_dt_timer_init(void)
of_node_put(np);
event_base = base + 0x4;
sts_base = base + 0x88;
source_base = cpu0_base + 0x24;
freq /= 4;
writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL);
@ -280,7 +282,8 @@ void __init msm_dt_timer_init(void)
}
#endif
static int __init msm_timer_map(phys_addr_t addr, u32 event, u32 source)
static int __init msm_timer_map(phys_addr_t addr, u32 event, u32 source,
u32 sts)
{
void __iomem *base;
@ -291,6 +294,8 @@ static int __init msm_timer_map(phys_addr_t addr, u32 event, u32 source)
}
event_base = base + event;
source_base = base + source;
if (sts)
sts_base = base + sts;
return 0;
}
@ -299,7 +304,7 @@ void __init msm7x01_timer_init(void)
{
struct clocksource *cs = &msm_clocksource;
if (msm_timer_map(0xc0100000, 0x0, 0x10))
if (msm_timer_map(0xc0100000, 0x0, 0x10, 0x0))
return;
cs->read = msm_read_timer_count_shift;
cs->mask = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT));
@ -310,14 +315,14 @@ void __init msm7x01_timer_init(void)
void __init msm7x30_timer_init(void)
{
if (msm_timer_map(0xc0100000, 0x4, 0x24))
if (msm_timer_map(0xc0100000, 0x4, 0x24, 0x80))
return;
msm_timer_init(24576000 / 4, 32, 1, false);
}
void __init qsd8x50_timer_init(void)
{
if (msm_timer_map(0xAC100000, 0x0, 0x10))
if (msm_timer_map(0xAC100000, 0x0, 0x10, 0x34))
return;
msm_timer_init(19200000 / 4, 32, 7, false);
}