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/*
* arch/arm/include/asm/mcpm.h
*
* Created by: Nicolas Pitre, April 2012
* Copyright: (C) 2012-2013 Linaro Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef MCPM_H
#define MCPM_H
/*
* Maximum number of possible clusters / CPUs per cluster.
*
* This should be sufficient for quite a while, while keeping the
* (assembly) code simpler. When this starts to grow then we'll have
* to consider dynamic allocation.
*/
#define MAX_CPUS_PER_CLUSTER 4
#define MAX_NR_CLUSTERS 2
#ifndef __ASSEMBLY__
/*
* Platform specific code should use this symbol to set up secondary
* entry location for processors to use when released from reset.
*/
extern void mcpm_entry_point(void);
/*
* This is used to indicate where the given CPU from given cluster should
* branch once it is ready to re-enter the kernel using ptr, or NULL if it
* should be gated. A gated CPU is held in a WFE loop until its vector
* becomes non NULL.
*/
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
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