[PATCH] clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

2013-08-26 Thread Tomasz Figa
Some variants of Exynos MCT, namely exynos4210-mct at the moment, use
normal, shared interrupts for local timers. This means that each
interrupt must have correct affinity set to fire only on CPU
corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the
local timer API for local timer initialization any more, the point of
time when local timers get initialized changed and irq_set_affinity()
fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to
CPU_ONLINE notification, so the affinity is being set when the CPU goes
online.

This fixes a problem with Exynos4210 failing to boot, present since commit
ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
due to failing irq_set_affinity().

Signed-off-by: Tomasz Figa t.f...@samsung.com
Signed-off-by: Kyungmin Park kyungmin.p...@samsung.com
---
 drivers/clocksource/exynos_mct.c | 10 +-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 5b34768..62b0de6 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -428,7 +428,6 @@ static int exynos4_local_timer_setup(struct 
clock_event_device *evt)
evt-irq);
return -EIO;
}
-   irq_set_affinity(evt-irq, cpumask_of(cpu));
} else {
enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
}
@@ -449,6 +448,7 @@ static int exynos4_mct_cpu_notify(struct notifier_block 
*self,
   unsigned long action, void *hcpu)
 {
struct mct_clock_event_device *mevt;
+   unsigned int cpu;
 
/*
 * Grab cpu pointer in each case to avoid spurious
@@ -459,6 +459,12 @@ static int exynos4_mct_cpu_notify(struct notifier_block 
*self,
mevt = this_cpu_ptr(percpu_mct_tick);
exynos4_local_timer_setup(mevt-evt);
break;
+   case CPU_ONLINE:
+   cpu = (unsigned long)hcpu;
+   if (mct_int_type == MCT_INT_SPI)
+   irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu],
+   cpumask_of(cpu));
+   break;
case CPU_DYING:
mevt = this_cpu_ptr(percpu_mct_tick);
exynos4_local_timer_stop(mevt-evt);
@@ -500,6 +506,8 @@ static void __init exynos4_timer_resources(struct 
device_node *np, void __iomem
 percpu_mct_tick);
WARN(err, MCT: can't request IRQ %d (%d)\n,
 mct_irqs[MCT_L0_IRQ], err);
+   } else {
+   irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
}
 
err = register_cpu_notifier(exynos4_mct_cpu_nb);
-- 
1.8.3.2

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Re: [PATCH] clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

2013-08-26 Thread Stephen Boyd
On 08/26, Tomasz Figa wrote:
 Some variants of Exynos MCT, namely exynos4210-mct at the moment, use
 normal, shared interrupts for local timers. This means that each
 interrupt must have correct affinity set to fire only on CPU
 corresponding to given local timer.
 
 However after recent conversion of clocksource drivers to not use the
 local timer API for local timer initialization any more, the point of
 time when local timers get initialized changed and irq_set_affinity()
 fails because the CPU is not marked as online yet.
 
 This patch fixes this by moving the call to irq_set_affinity() to
 CPU_ONLINE notification, so the affinity is being set when the CPU goes
 online.
 
 This fixes a problem with Exynos4210 failing to boot, present since commit
   ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
 due to failing irq_set_affinity().
 
 Signed-off-by: Tomasz Figa t.f...@samsung.com
 Signed-off-by: Kyungmin Park kyungmin.p...@samsung.com
 ---

Looks good to me if you want to go this route.

Acked-by: Stephen Boyd sb...@codeaurora.org

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Re: [PATCH] clocksource: exynos_mct: Set IRQ affinity when the CPU goes online

2013-08-26 Thread Tomasz Figa
On Monday 26 of August 2013 16:09:41 Stephen Boyd wrote:
 On 08/26, Tomasz Figa wrote:
  Some variants of Exynos MCT, namely exynos4210-mct at the moment, use
  normal, shared interrupts for local timers. This means that each
  interrupt must have correct affinity set to fire only on CPU
  corresponding to given local timer.
  
  However after recent conversion of clocksource drivers to not use the
  local timer API for local timer initialization any more, the point of
  time when local timers get initialized changed and irq_set_affinity()
  fails because the CPU is not marked as online yet.
  
  This patch fixes this by moving the call to irq_set_affinity() to
  CPU_ONLINE notification, so the affinity is being set when the CPU
  goes
  online.
  
  This fixes a problem with Exynos4210 failing to boot, present since
  commit 
  ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
  
  due to failing irq_set_affinity().
  
  Signed-off-by: Tomasz Figa t.f...@samsung.com
  Signed-off-by: Kyungmin Park kyungmin.p...@samsung.com
  ---
 
 Looks good to me if you want to go this route.
 
 Acked-by: Stephen Boyd sb...@codeaurora.org

Thanks. After some testing this seems to work fine and I don't see any 
reason how the timer could be programmed to fire an interrupt before the 
CPU goes online, so it should be fine.

Anyway, we want this to be fixed for 3.12 for sure and since I don't 
really see any better solution we should take this one.

Best regards,
Tomasz

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