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author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2012-09-20 16:05:37 -0400 |
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committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2013-04-24 10:36:59 -0400 |
commit | 7c2b860534d02d11923dd0504b961f21508173f1 (patch) | |
tree | 643030cebe48d267e67eb9b533284db881ef99a5 /arch/arm/include | |
parent | e8db288e05e588ad3f416b3a24354d60d02f35f2 (diff) | |
download | linux-7c2b860534d02d11923dd0504b961f21508173f1.tar.gz linux-7c2b860534d02d11923dd0504b961f21508173f1.tar.bz2 linux-7c2b860534d02d11923dd0504b961f21508173f1.zip |
ARM: mcpm: introduce the CPU/cluster power API
This is the basic API used to handle the powering up/down of individual
CPUs in a (multi-)cluster system. The platform specific backend
implementation has the responsibility to also handle the cluster level
power as well when the first/last CPU in a cluster is brought up/down.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm/include')
-rw-r--r-- | arch/arm/include/asm/mcpm.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h index 470a417d1351..627761fce780 100644 --- a/arch/arm/include/asm/mcpm.h +++ b/arch/arm/include/asm/mcpm.h @@ -38,5 +38,97 @@ extern void mcpm_entry_point(void); */ void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr); +/* + * CPU/cluster power operations API for higher subsystems to use. + */ + +/** + * mcpm_cpu_power_up - make given CPU in given cluster runable + * + * @cpu: CPU number within given cluster + * @cluster: cluster number for the CPU + * + * The identified CPU is brought out of reset. If the cluster was powered + * down then it is brought up as well, taking care not to let the other CPUs + * in the cluster run, and ensuring appropriate cluster setup. + * + * Caller must ensure the appropriate entry vector is initialized with + * mcpm_set_entry_vector() prior to calling this. + * + * This must be called in a sleepable context. However, the implementation + * is strongly encouraged to return early and let the operation happen + * asynchronously, especially when significant delays are expected. + * + * If the operation cannot be performed then an error code is returned. + */ +int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster); + +/** + * mcpm_cpu_power_down - power the calling CPU down + * + * The calling CPU is powered down. + * + * If this CPU is found to be the "last man standing" in the cluster + * then the cluster is prepared for power-down too. + * + * This must be called with interrupts disabled. + * + * This does not return. Re-entry in the kernel is expected via + * mcpm_entry_point. + */ +void mcpm_cpu_power_down(void); + +/** + * mcpm_cpu_suspend - bring the calling CPU in a suspended state + * + * @expected_residency: duration in microseconds the CPU is expected + * to remain suspended, or 0 if unknown/infinity. + * + * The calling CPU is suspended. The expected residency argument is used + * as a hint by the platform specific backend to implement the appropriate + * sleep state level according to the knowledge it has on wake-up latency + * for the given hardware. + * + * If this CPU is found to be the "last man standing" in the cluster + * then the cluster may be prepared for power-down too, if the expected + * residency makes it worthwhile. + * + * This must be called with interrupts disabled. + * + * This does not return. Re-entry in the kernel is expected via + * mcpm_entry_point. + */ +void mcpm_cpu_suspend(u64 expected_residency); + +/** + * mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up + * + * This lets the platform specific backend code perform needed housekeeping + * work. This must be called by the newly activated CPU as soon as it is + * fully operational in kernel space, before it enables interrupts. + * + * If the operation cannot be performed then an error code is returned. + */ +int mcpm_cpu_powered_up(void); + +/* + * Platform specific methods used in the implementation of the above API. + */ +struct mcpm_platform_ops { + int (*power_up)(unsigned int cpu, unsigned int cluster); + void (*power_down)(void); + void (*suspend)(u64); + void (*powered_up)(void); +}; + +/** + * mcpm_platform_register - register platform specific power methods + * + * @ops: mcpm_platform_ops structure to register + * + * An error is returned if the registration has been done previously. + */ +int __init mcpm_platform_register(const struct mcpm_platform_ops *ops); + #endif /* ! __ASSEMBLY__ */ #endif |