[PATCH v2] ARM: imx: disable cpu in .cpu_kill hook
Shawn Guo
shawn.guo at linaro.org
Mon Jan 14 09:23:21 EST 2013
It's buggy to disable the cpu that is being hot-unplugged in .cpu_die
hook which runs on the cpu itself. Instead, it should be done in
.cpu_kill which runs on the thread (another cpu) that asks for shutting
down the cpu. Move imx_enable_cpu(cpu, false) call into .cpu_kill
hook, and leave the cpu to be hot-unplugged in WFI within .cpu_die,
so that we can get a more stable cpu hot-plug operation.
Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
---
arch/arm/mach-imx/common.h | 1 +
arch/arm/mach-imx/hotplug.c | 10 ++++++----
arch/arm/mach-imx/platsmp.c | 1 +
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index 7191ab4..fa36fb8 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -142,6 +142,7 @@ extern int imx6q_set_lpm(enum mxc_cpu_pwr_mode mode);
extern void imx6q_clock_map_io(void);
extern void imx_cpu_die(unsigned int cpu);
+extern int imx_cpu_kill(unsigned int cpu);
#ifdef CONFIG_PM
extern void imx6q_pm_init(void);
diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
index 3dec962..7bc5fe1 100644
--- a/arch/arm/mach-imx/hotplug.c
+++ b/arch/arm/mach-imx/hotplug.c
@@ -46,9 +46,11 @@ static inline void cpu_enter_lowpower(void)
void imx_cpu_die(unsigned int cpu)
{
cpu_enter_lowpower();
- imx_enable_cpu(cpu, false);
+ cpu_do_idle();
+}
- /* spin here until hardware takes it down */
- while (1)
- ;
+int imx_cpu_kill(unsigned int cpu)
+{
+ imx_enable_cpu(cpu, false);
+ return 1;
}
diff --git a/arch/arm/mach-imx/platsmp.c b/arch/arm/mach-imx/platsmp.c
index 3777b80..66fae88 100644
--- a/arch/arm/mach-imx/platsmp.c
+++ b/arch/arm/mach-imx/platsmp.c
@@ -92,5 +92,6 @@ struct smp_operations imx_smp_ops __initdata = {
.smp_boot_secondary = imx_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = imx_cpu_die,
+ .cpu_kill = imx_cpu_kill,
#endif
};
--
1.7.9.5
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