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Commit 1229835c authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
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ARM: mach-shmobile: Flush caches in platform_cpu_die() 



Add cache flushing code to the SH-Mobile specific CPU hotplug
implementation. While at it, add a cpu mask to make sure the
cache flushing code is finished in platform_cpu_die() before
letting the SoC-specific code in shmobile_platform_cpu_kill()
proceed with turning off power.

Without this code CPU hotplug offline fails when cache is
enabled on Cortex-A9 based SoCs.

Signed-off-by: default avatarMagnus Damm <damm@opensource.se>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 8b306796

arch/arm/mach-shmobile/hotplug.c

+30 −1
Original line number Diff line number Diff line
@@ -12,15 +12,43 @@ 
#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/smp.h>

#include <linux/cpumask.h>

#include <linux/delay.h>

#include <mach/common.h>

#include <asm/cacheflush.h>



static cpumask_t dead_cpus;



int platform_cpu_kill(unsigned int cpu)

{

	int k;



	/* this function is running on another CPU than the offline target,

	 * here we need wait for shutdown code in platform_cpu_die() to

	 * finish before asking SoC-specific code to power off the CPU core.

	 */

	for (k = 0; k < 1000; k++) {

		if (cpumask_test_cpu(cpu, &dead_cpus))

			return shmobile_platform_cpu_kill(cpu);



		mdelay(1);

	}



	return 0;

}



void platform_cpu_die(unsigned int cpu)

{

	/* hardware shutdown code running on the CPU that is being offlined */

	flush_cache_all();

	dsb();



	/* notify platform_cpu_kill() that hardware shutdown is finished */

	cpumask_set_cpu(cpu, &dead_cpus);



	/* wait for SoC code in platform_cpu_kill() to shut off CPU core

	 * power. CPU bring up starts from the reset vector.

	 */

	while (1) {

		/*

		 * here's the WFI
@@ -34,6 +62,7 @@ void platform_cpu_die(unsigned int cpu) 


int platform_cpu_disable(unsigned int cpu)

{

	cpumask_clear_cpu(cpu, &dead_cpus);

	/*

	 * we don't allow CPU 0 to be shutdown (it is still too special

	 * e.g. clock tick interrupts)