diff options
| author | Magnus Damm <damm@opensource.se> | 2011-12-28 16:53:16 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2012-01-09 10:37:29 +0900 |
| commit | 1229835ccb6d7ea2b36230121205be95c88eca88 (patch) | |
| tree | 7b8c0e49cc88b6a554552e8dd70ae52d1baefd76 /arch/arm | |
| parent | 8b306796995609c281f6d32b3cbaa814551ad5ac (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.c | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/arch/arm/mach-shmobile/hotplug.c b/arch/arm/mach-shmobile/hotplug.c index aee3a1088a5a..828d22f3af57 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) |