[deliverable/linux.git] / arch / arm / include / asm / mcpm.h

/*
 * 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__

#include <linux/types.h>
#include <asm/cacheflush.h>

/*
 * 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.
 *
 * On success this does not return.  Re-entry in the kernel is expected
 * via mcpm_entry_point.
 *
 * This will return if mcpm_platform_register() has not been called
 * previously in which case the caller should take appropriate action.
 */
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.
 *
 * On success this does not return.  Re-entry in the kernel is expected
 * via mcpm_entry_point.
 *
 * This will return if mcpm_platform_register() has not been called
 * previously in which case the caller should take appropriate action.
 */
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);

/* Synchronisation structures for coordinating safe cluster setup/teardown: */

/*
 * When modifying this structure, make sure you update the MCPM_SYNC_ defines
 * to match.
 */
struct mcpm_sync_struct {
	/* individual CPU states */
	struct {
		s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE);
	} cpus[MAX_CPUS_PER_CLUSTER];

	/* cluster state */
	s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE);

	/* inbound-side state */
	s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE);
};

struct sync_struct {
	struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS];
};

extern unsigned long sync_phys;	/* physical address of *mcpm_sync */

void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster);
void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster);
void __mcpm_outbound_leave_critical(unsigned int cluster, int state);
bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster);
int __mcpm_cluster_state(unsigned int cluster);

int __init mcpm_sync_init(
	void (*power_up_setup)(unsigned int affinity_level));

void __init mcpm_smp_set_ops(void);

#else

/* 
 * asm-offsets.h causes trouble when included in .c files, and cacheflush.h
 * cannot be included in asm files.  Let's work around the conflict like this.
 */
#include <asm/asm-offsets.h>
#define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE

#endif /* ! __ASSEMBLY__ */

/* Definitions for mcpm_sync_struct */
#define CPU_DOWN		0x11
#define CPU_COMING_UP		0x12
#define CPU_UP			0x13
#define CPU_GOING_DOWN		0x14

#define CLUSTER_DOWN		0x21
#define CLUSTER_UP		0x22
#define CLUSTER_GOING_DOWN	0x23

#define INBOUND_NOT_COMING_UP	0x31
#define INBOUND_COMING_UP	0x32

/*
 * Offsets for the mcpm_sync_struct members, for use in asm.
 * We don't want to make them global to the kernel via asm-offsets.c.
 */
#define MCPM_SYNC_CLUSTER_CPUS	0
#define MCPM_SYNC_CPU_SIZE	__CACHE_WRITEBACK_GRANULE
#define MCPM_SYNC_CLUSTER_CLUSTER \
	(MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER)
#define MCPM_SYNC_CLUSTER_INBOUND \
	(MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE)
#define MCPM_SYNC_CLUSTER_SIZE \
	(MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE)

#endif
Commit	Line	Data
e8db288e NP	1	/*
	2	* arch/arm/include/asm/mcpm.h
	3	*
	4	* Created by: Nicolas Pitre, April 2012
	5	* Copyright: (C) 2012-2013 Linaro Limited
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	#ifndef MCPM_H
	13	#define MCPM_H
	14
	15	/*
	16	* Maximum number of possible clusters / CPUs per cluster.
	17	*
	18	* This should be sufficient for quite a while, while keeping the
	19	* (assembly) code simpler. When this starts to grow then we'll have
	20	* to consider dynamic allocation.
	21	*/
	22	#define MAX_CPUS_PER_CLUSTER 4
	23	#define MAX_NR_CLUSTERS 2
	24
	25	#ifndef __ASSEMBLY__
	26
7fe31d28 DM	27	#include <linux/types.h>
	28	#include <asm/cacheflush.h>
	29
e8db288e NP	30	/*
	31	* Platform specific code should use this symbol to set up secondary
	32	* entry location for processors to use when released from reset.
	33	*/
	34	extern void mcpm_entry_point(void);
	35
	36	/*
	37	* This is used to indicate where the given CPU from given cluster should
	38	* branch once it is ready to re-enter the kernel using ptr, or NULL if it
	39	* should be gated. A gated CPU is held in a WFE loop until its vector
	40	* becomes non NULL.
	41	*/
	42	void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr);
	43
7c2b8605 NP	44	/*
	45	* CPU/cluster power operations API for higher subsystems to use.
	46	*/
	47
	48	/**
	49	* mcpm_cpu_power_up - make given CPU in given cluster runable
	50	*
	51	* @cpu: CPU number within given cluster
	52	* @cluster: cluster number for the CPU
	53	*
	54	* The identified CPU is brought out of reset. If the cluster was powered
	55	* down then it is brought up as well, taking care not to let the other CPUs
	56	* in the cluster run, and ensuring appropriate cluster setup.
	57	*
	58	* Caller must ensure the appropriate entry vector is initialized with
	59	* mcpm_set_entry_vector() prior to calling this.
	60	*
	61	* This must be called in a sleepable context. However, the implementation
	62	* is strongly encouraged to return early and let the operation happen
	63	* asynchronously, especially when significant delays are expected.
	64	*
	65	* If the operation cannot be performed then an error code is returned.
	66	*/
	67	int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster);
	68
	69	/**
	70	* mcpm_cpu_power_down - power the calling CPU down
	71	*
	72	* The calling CPU is powered down.
	73	*
	74	* If this CPU is found to be the "last man standing" in the cluster
	75	* then the cluster is prepared for power-down too.
	76	*
	77	* This must be called with interrupts disabled.
	78	*
d0cdef6e NP	79	* On success this does not return. Re-entry in the kernel is expected
	80	* via mcpm_entry_point.
	81	*
	82	* This will return if mcpm_platform_register() has not been called
	83	* previously in which case the caller should take appropriate action.
7c2b8605 NP	84	*/
	85	void mcpm_cpu_power_down(void);
	86
	87	/**
	88	* mcpm_cpu_suspend - bring the calling CPU in a suspended state
	89	*
	90	* @expected_residency: duration in microseconds the CPU is expected
	91	* to remain suspended, or 0 if unknown/infinity.
	92	*
	93	* The calling CPU is suspended. The expected residency argument is used
	94	* as a hint by the platform specific backend to implement the appropriate
	95	* sleep state level according to the knowledge it has on wake-up latency
	96	* for the given hardware.
	97	*
	98	* If this CPU is found to be the "last man standing" in the cluster
	99	* then the cluster may be prepared for power-down too, if the expected
	100	* residency makes it worthwhile.
	101	*
	102	* This must be called with interrupts disabled.
	103	*
d0cdef6e NP	104	* On success this does not return. Re-entry in the kernel is expected
	105	* via mcpm_entry_point.
	106	*
	107	* This will return if mcpm_platform_register() has not been called
	108	* previously in which case the caller should take appropriate action.
7c2b8605 NP	109	*/
	110	void mcpm_cpu_suspend(u64 expected_residency);
	111
	112	/**
	113	* mcpm_cpu_powered_up - housekeeping workafter a CPU has been powered up
	114	*
	115	* This lets the platform specific backend code perform needed housekeeping
	116	* work. This must be called by the newly activated CPU as soon as it is
	117	* fully operational in kernel space, before it enables interrupts.
	118	*
	119	* If the operation cannot be performed then an error code is returned.
	120	*/
	121	int mcpm_cpu_powered_up(void);
	122
	123	/*
	124	* Platform specific methods used in the implementation of the above API.
	125	*/
	126	struct mcpm_platform_ops {
	127	int (*power_up)(unsigned int cpu, unsigned int cluster);
	128	void (*power_down)(void);
	129	void (*suspend)(u64);
	130	void (*powered_up)(void);
	131	};
	132
	133	/**
	134	* mcpm_platform_register - register platform specific power methods
	135	*
	136	* @ops: mcpm_platform_ops structure to register
	137	*
	138	* An error is returned if the registration has been done previously.
	139	*/
	140	int __init mcpm_platform_register(const struct mcpm_platform_ops *ops);
	141
7fe31d28 DM	142	/* Synchronisation structures for coordinating safe cluster setup/teardown: */
	143
	144	/*
	145	* When modifying this structure, make sure you update the MCPM_SYNC_ defines
	146	* to match.
	147	*/
	148	struct mcpm_sync_struct {
	149	/* individual CPU states */
	150	struct {
	151	s8 cpu __aligned(__CACHE_WRITEBACK_GRANULE);
	152	} cpus[MAX_CPUS_PER_CLUSTER];
	153
	154	/* cluster state */
	155	s8 cluster __aligned(__CACHE_WRITEBACK_GRANULE);
	156
	157	/* inbound-side state */
	158	s8 inbound __aligned(__CACHE_WRITEBACK_GRANULE);
	159	};
	160
	161	struct sync_struct {
	162	struct mcpm_sync_struct clusters[MAX_NR_CLUSTERS];
	163	};
	164
	165	extern unsigned long sync_phys; /* physical address of mcpm_sync /
	166
	167	void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster);
	168	void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster);
	169	void __mcpm_outbound_leave_critical(unsigned int cluster, int state);
	170	bool __mcpm_outbound_enter_critical(unsigned int this_cpu, unsigned int cluster);
	171	int __mcpm_cluster_state(unsigned int cluster);
	172
	173	int __init mcpm_sync_init(
	174	void (*power_up_setup)(unsigned int affinity_level));
	175
a7eb7c6f NP	176	void __init mcpm_smp_set_ops(void);
a7eb7c6f NP	177
7fe31d28 DM	178	#else
	179
	180	/*
	181	* asm-offsets.h causes trouble when included in .c files, and cacheflush.h
	182	* cannot be included in asm files. Let's work around the conflict like this.
	183	*/
	184	#include <asm/asm-offsets.h>
	185	#define __CACHE_WRITEBACK_GRANULE CACHE_WRITEBACK_GRANULE
	186
e8db288e	187	#endif /* ! __ASSEMBLY__ */
7fe31d28 DM	188
	189	/* Definitions for mcpm_sync_struct */
	190	#define CPU_DOWN 0x11
	191	#define CPU_COMING_UP 0x12
	192	#define CPU_UP 0x13
	193	#define CPU_GOING_DOWN 0x14
	194
	195	#define CLUSTER_DOWN 0x21
	196	#define CLUSTER_UP 0x22
	197	#define CLUSTER_GOING_DOWN 0x23
	198
	199	#define INBOUND_NOT_COMING_UP 0x31
	200	#define INBOUND_COMING_UP 0x32
	201
	202	/*
	203	* Offsets for the mcpm_sync_struct members, for use in asm.
	204	* We don't want to make them global to the kernel via asm-offsets.c.
	205	*/
	206	#define MCPM_SYNC_CLUSTER_CPUS 0
	207	#define MCPM_SYNC_CPU_SIZE __CACHE_WRITEBACK_GRANULE
	208	#define MCPM_SYNC_CLUSTER_CLUSTER \
	209	(MCPM_SYNC_CLUSTER_CPUS + MCPM_SYNC_CPU_SIZE * MAX_CPUS_PER_CLUSTER)
	210	#define MCPM_SYNC_CLUSTER_INBOUND \
	211	(MCPM_SYNC_CLUSTER_CLUSTER + __CACHE_WRITEBACK_GRANULE)
	212	#define MCPM_SYNC_CLUSTER_SIZE \
	213	(MCPM_SYNC_CLUSTER_INBOUND + __CACHE_WRITEBACK_GRANULE)
	214
e8db288e	215	#endif