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authorMagnus Damm <damm@opensource.se>2011-12-28 16:53:16 +0900
committerPaul Mundt <lethal@linux-sh.org>2012-01-09 10:37:29 +0900
commit1229835ccb6d7ea2b36230121205be95c88eca88 (patch)
tree7b8c0e49cc88b6a554552e8dd70ae52d1baefd76 /arch/arm
parent8b306796995609c281f6d32b3cbaa814551ad5ac (diff)
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: Magnus Damm <damm@opensource.se> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mach-shmobile/hotplug.c31
1 files changed, 30 insertions, 1 deletions
diff --git a/arch/arm/mach-shmobile/hotplug.c b/arch/arm/mach-shmobile/hotplug.c
index aee3a1088a5..828d22f3af5 100644
--- a/arch/arm/mach-shmobile/hotplug.c
+++ b/arch/arm/mach-shmobile/hotplug.c
@@ -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)
{
- return shmobile_platform_cpu_kill(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)