diff options
| -rw-r--r-- | arch/arm/common/mcpm_entry.c | 15 | ||||
| -rw-r--r-- | arch/arm/common/mcpm_platsmp.c | 10 | ||||
| -rw-r--r-- | arch/arm/include/asm/mcpm.h | 31 |
3 files changed, 56 insertions, 0 deletions
diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c index 990250965f2c..6c03d0152e7f 100644 --- a/arch/arm/common/mcpm_entry.c +++ b/arch/arm/common/mcpm_entry.c @@ -90,6 +90,21 @@ void mcpm_cpu_power_down(void) BUG(); } +int mcpm_cpu_power_down_finish(unsigned int cpu, unsigned int cluster) +{ + int ret; + + if (WARN_ON_ONCE(!platform_ops || !platform_ops->power_down_finish)) + return -EUNATCH; + + ret = platform_ops->power_down_finish(cpu, cluster); + if (ret) + pr_warn("%s: cpu %u, cluster %u failed to power down (%d)\n", + __func__, cpu, cluster, ret); + + return ret; +} + void mcpm_cpu_suspend(u64 expected_residency) { phys_reset_t phys_reset; diff --git a/arch/arm/common/mcpm_platsmp.c b/arch/arm/common/mcpm_platsmp.c index c0c3cd799ccc..177251a4dd9a 100644 --- a/arch/arm/common/mcpm_platsmp.c +++ b/arch/arm/common/mcpm_platsmp.c @@ -56,6 +56,15 @@ static void mcpm_secondary_init(unsigned int cpu) #ifdef CONFIG_HOTPLUG_CPU +static int mcpm_cpu_kill(unsigned int cpu) +{ + unsigned int pcpu, pcluster; + + cpu_to_pcpu(cpu, &pcpu, &pcluster); + + return !mcpm_cpu_power_down_finish(pcpu, pcluster); +} + static int mcpm_cpu_disable(unsigned int cpu) { /* @@ -82,6 +91,7 @@ static struct smp_operations __initdata mcpm_smp_ops = { .smp_boot_secondary = mcpm_boot_secondary, .smp_secondary_init = mcpm_secondary_init, #ifdef CONFIG_HOTPLUG_CPU + .cpu_kill = mcpm_cpu_kill, .cpu_disable = mcpm_cpu_disable, .cpu_die = mcpm_cpu_die, #endif diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h index fc82a88f5b69..1cf26010a6f3 100644 --- a/arch/arm/include/asm/mcpm.h +++ b/arch/arm/include/asm/mcpm.h @@ -81,10 +81,40 @@ int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster); * * This will return if mcpm_platform_register() has not been called * previously in which case the caller should take appropriate action. + * + * On success, the CPU is not guaranteed to be truly halted until + * mcpm_cpu_power_down_finish() subsequently returns non-zero for the + * specified cpu. Until then, other CPUs should make sure they do not + * trash memory the target CPU might be executing/accessing. */ void mcpm_cpu_power_down(void); /** + * mcpm_cpu_power_down_finish - wait for a specified CPU to halt, and + * make sure it is powered off + * + * @cpu: CPU number within given cluster + * @cluster: cluster number for the CPU + * + * Call this function to ensure that a pending powerdown has taken + * effect and the CPU is safely parked before performing non-mcpm + * operations that may affect the CPU (such as kexec trashing the + * kernel text). + * + * It is *not* necessary to call this function if you only need to + * serialise a pending powerdown with mcpm_cpu_power_up() or a wakeup + * event. + * + * Do not call this function unless the specified CPU has already + * called mcpm_cpu_power_down() or has committed to doing so. + * + * @return: + * - zero if the CPU is in a safely parked state + * - nonzero otherwise (e.g., timeout) + */ +int mcpm_cpu_power_down_finish(unsigned int cpu, unsigned int cluster); + +/** * mcpm_cpu_suspend - bring the calling CPU in a suspended state * * @expected_residency: duration in microseconds the CPU is expected @@ -126,6 +156,7 @@ int mcpm_cpu_powered_up(void); struct mcpm_platform_ops { int (*power_up)(unsigned int cpu, unsigned int cluster); void (*power_down)(void); + int (*power_down_finish)(unsigned int cpu, unsigned int cluster); void (*suspend)(u64); void (*powered_up)(void); }; |