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ARM: mach-shmobile: Flush caches in platform_cpu_die()

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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: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Magnus Damm
2011-12-28 16:53:16 +09:00
committed by Paul Mundt
parent 8b30679699
commit 1229835ccb
1 changed files with 30 additions and 1 deletions
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29
arch/arm/mach-shmobile/hotplug.c
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@@ -12,15 +12,43 @@
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/smp.h> #include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <mach/common.h> #include <mach/common.h>
#include <asm/cacheflush.h>
static cpumask_t dead_cpus;
int platform_cpu_kill(unsigned int cpu) 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); return shmobile_platform_cpu_kill(cpu);
mdelay(1);
}
return 0;
} }
void platform_cpu_die(unsigned int cpu) 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) { while (1) {
/* /*
* here's the WFI * here's the WFI
@@ -34,6 +62,7 @@ void platform_cpu_die(unsigned int cpu)
int platform_cpu_disable(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 * we don't allow CPU 0 to be shutdown (it is still too special
* e.g. clock tick interrupts) * e.g. clock tick interrupts)