On 05/27/2011 09:27 AM, Marc Zyngier wrote:

Use the normal interrupt scheme for the local timers by using
a remapped PPI interrupt.

MSM already had a very similar scheme, though still mixing both
GIC-specific and generic APIs.

Fixes and ideas courtesy of Stephen Boyd.

Cc: David Brown <redacted>
Cc: Daniel Walker <redacted>
Cc: Bryan Huntsman <redacted>

Reviewed-and-Tested-by: Stephen Boyd [off-list ref]

 
+static bool local_timer_inited;

Except this is unused if SMP=n. Here's a fix:

---8<----

diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
index 186abdf..a242b89 100644
--- a/arch/arm/mach-msm/timer.c
+++ b/arch/arm/mach-msm/timer.c

@@ -84,7 +84,6 @@ enum {
 
 
 static struct msm_clock msm_clocks[];
-static bool local_timer_inited;
 
 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
 {

@@ -259,6 +258,7 @@ int __cpuinit local_timer_setup(struct clock_event_device *evt)
 {
        struct msm_clock *clock = &msm_clocks[MSM_GLOBAL_TIMER];
        int res;
+       static bool local_timer_inited;
 
        /* Use existing clock_event for cpu 0 */
        if (!smp_processor_id())



---

But now I really want to know. Why can't we use system_state ==
SYSTEM_BOOTING? Perhaps I'm thinking ahead too much, but I'm concerned
that if we have more than two cores we're going to have to make a percpu
variable here just to avoid requesting the irq again. It would be
simpler to just accept the fact that we can't boot a secondary core for
the first time after kernel init due to the way the code is written.
If/when we decide to allow such a thing we can revisit this code and
make it into a percpu variable.

Or another idea is to pass a "first_boot" flag or something to
local_timer_setup() to indicate this is the first boot. Then we could
extend the percpu_clockevent variable in the localtimer core to have
this flag.

Either way it seems like something we should centralize.

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.