[PATCH v2 RESEND 1/2] ARM: arch timer: Set the TVAL before timer is enabled

From: Rohit Vaswani
Date: Sat Sep 15 2012 - 03:42:34 EST


On some hardware, the timer deasserts the interrupt when a
new TVAL is written only when the enable bit is cleared.
Hence explicitly disable the timer and then program the
TVAL followed by enabling the timer.
If this order is not followed, there are chances that
you would not receive any timer interrupts.

Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
---
arch/arm/kernel/arch_timer.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index c04c2a6..8672a75 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -206,9 +206,10 @@ static inline void set_next_event(const int access, unsigned long evt)
{
unsigned long ctrl;
ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
- ctrl |= ARCH_TIMER_CTRL_ENABLE;
- ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
+ ctrl &= ~(ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_MASK);
+ arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt);
+ ctrl |= ARCH_TIMER_CTRL_ENABLE;
arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
}

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/