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Subject[RFC PATCH RESEND] ARM: spear: send SGI to trigger secondary CPU start
Date
The ARM spear machine uses the "holding pen" mechanism for starting
secondary CPUs. Most implementations indicate it's a secondary
core's time to start by writing its CPU id into a location and
then signaling the core with a software-generated interrupt.

The spear code does not send the signal. Comments elsewhere
in the code seem to indicate it should:
The BootMonitor waits until it receives a soft interrupt, and
then the secondary CPU branches to this address.

I suspect this is an oversight, and this patch proposes a remedy.

*** I need the attention of a maintainer to verify this
*** because I am unable to test this proposed change.

Signed-off-by: Alex Elder <elder@linaro.org>
---
arch/arm/mach-spear/platsmp.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm/mach-spear/platsmp.c b/arch/arm/mach-spear/platsmp.c
index 5c4a198..c9064fe 100644
--- a/arch/arm/mach-spear/platsmp.c
+++ b/arch/arm/mach-spear/platsmp.c
@@ -62,6 +62,8 @@ static int spear13xx_boot_secondary(unsigned int cpu, struct task_struct *idle)
flush_cache_all();
outer_flush_all();

+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
smp_rmb();
--
1.7.9.5


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