lib/psci/psci_stat.c - filogic/atf - Gitiles

 /*
  * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * Redistributions of source code must retain the above copyright notice, this
  * list of conditions and the following disclaimer.
  *
  * Redistributions in binary form must reproduce the above copyright notice,
  * this list of conditions and the following disclaimer in the documentation
  * and/or other materials provided with the distribution.
  *
  * Neither the name of ARM nor the names of its contributors may be used
  * to endorse or promote products derived from this software without specific
  * prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */

 #include <assert.h>
 #include <debug.h>
 #include <platform.h>
 #include <platform_def.h>
 #include "psci_private.h"

 #ifndef PLAT_MAX_PWR_LVL_STATES
 #define PLAT_MAX_PWR_LVL_STATES 2
 #endif

 /* Ticks elapsed in one second by a signal of 1 MHz */
 #define MHZ_TICKS_PER_SEC 1000000

 /* Following structure is used for PSCI STAT */
 typedef struct psci_stat {
 	u_register_t residency;
 	u_register_t count;
 } psci_stat_t;

 /*
  * Following is used to keep track of the last cpu
  * that goes to power down in non cpu power domains.
  */
 static int last_cpu_in_non_cpu_pd[PSCI_NUM_NON_CPU_PWR_DOMAINS] = {-1};

 /*
  * Following are used to store PSCI STAT values for
  * CPU and non CPU power domains.
  */
 static psci_stat_t psci_cpu_stat[PLATFORM_CORE_COUNT]
 				[PLAT_MAX_PWR_LVL_STATES];
 static psci_stat_t psci_non_cpu_stat[PSCI_NUM_NON_CPU_PWR_DOMAINS]
 				[PLAT_MAX_PWR_LVL_STATES];

 /* Register PMF PSCI service */
 PMF_REGISTER_SERVICE(psci_svc, PMF_PSCI_STAT_SVC_ID,
 	 PSCI_STAT_TOTAL_IDS, PMF_STORE_ENABLE)

 /* The divisor to use to convert raw timestamp into microseconds */
 u_register_t residency_div;

 /*
  * This macro calculates the stats residency in microseconds,
  * taking in account the wrap around condition.
  */
 #define calc_stat_residency(_pwrupts, _pwrdnts, _res)		\
 	do {							\
 		if (_pwrupts < _pwrdnts)			\
 			_res = UINT64_MAX - _pwrdnts + _pwrupts;\
 		else						\
 			_res = _pwrupts - _pwrdnts;		\
 		/* Convert timestamp into microseconds */	\
 		_res = _res/residency_div;			\
 	} while (0)

 /*
  * This functions returns the index into the `psci_stat_t` array given the
  * local power state and power domain level. If the platform implements the
  * `get_pwr_lvl_state_idx` pm hook, then that will be used to return the index.
  */
 static int get_stat_idx(plat_local_state_t local_state, int pwr_lvl)
 {
 	int idx;

 	if (psci_plat_pm_ops->get_pwr_lvl_state_idx == NULL) {
 		assert(PLAT_MAX_PWR_LVL_STATES == 2);
 		if (is_local_state_retn(local_state))
 			return 0;

 		assert(is_local_state_off(local_state));
 		return 1;
 	}

 	idx = psci_plat_pm_ops->get_pwr_lvl_state_idx(local_state, pwr_lvl);
 	assert((idx >= 0) && (idx < PLAT_MAX_PWR_LVL_STATES));
 	return idx;
 }

 /*******************************************************************************
  * This function is passed the target local power states for each power
  * domain (state_info) between the current CPU domain and its ancestors until
  * the target power level (end_pwrlvl).
  *
  * Then, for each level (apart from the CPU level) until the 'end_pwrlvl', it
  * updates the `last_cpu_in_non_cpu_pd[]` with last power down cpu id.
  *
  * This function will only be invoked with data cache enabled and while
  * powering down a core.
  ******************************************************************************/
 void psci_stats_update_pwr_down(unsigned int end_pwrlvl,
 			const psci_power_state_t *state_info)
 {
 	int lvl, parent_idx, cpu_idx = plat_my_core_pos();

 	assert(end_pwrlvl <= PLAT_MAX_PWR_LVL);
 	assert(state_info);

 	parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;

 	for (lvl = PSCI_CPU_PWR_LVL + 1; lvl <= end_pwrlvl; lvl++) {

 		/* Break early if the target power state is RUN */
 		if (is_local_state_run(state_info->pwr_domain_state[lvl]))
 			break;

 		/*
 		 * The power domain is entering a low power state, so this is
 		 * the last CPU for this power domain
 		 */
 		last_cpu_in_non_cpu_pd[parent_idx] = cpu_idx;

 		parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;
 	}

 }

 /*******************************************************************************
  * This function updates the PSCI STATS(residency time and count) for CPU
  * and NON-CPU power domains.
  * It is called with caches enabled and locks acquired(for NON-CPU domain)
  ******************************************************************************/
 void psci_stats_update_pwr_up(unsigned int end_pwrlvl,
 			const psci_power_state_t *state_info,
 			unsigned int flags)
 {
 	int parent_idx, cpu_idx = plat_my_core_pos();
 	int lvl, stat_idx;
 	plat_local_state_t local_state;
 	unsigned long long pwrup_ts = 0, pwrdn_ts = 0;
 	u_register_t residency;

 	assert(end_pwrlvl <= PLAT_MAX_PWR_LVL);
 	assert(state_info);

 	/* Initialize the residency divisor if not already initialized */
 	if (!residency_div) {
 		/* Pre-calculate divisor so that it can be directly used to
 		   convert time-stamp into microseconds */
 		residency_div = read_cntfrq_el0() / MHZ_TICKS_PER_SEC;
 		assert(residency_div);
 	}

 	/* Get power down time-stamp for current CPU */
 	PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_ENTER_LOW_PWR,
 			cpu_idx, flags, pwrdn_ts);

 	/* In the case of 1st power on just return */
 	if (!pwrdn_ts)
 		return;

 	/* Get power up time-stamp for current CPU */
 	PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_EXIT_LOW_PWR,
 			cpu_idx, flags, pwrup_ts);

 	/* Get the index into the stats array */
 	local_state = state_info->pwr_domain_state[PSCI_CPU_PWR_LVL];
 	stat_idx = get_stat_idx(local_state, PSCI_CPU_PWR_LVL);

 	/* Calculate stats residency */
 	calc_stat_residency(pwrup_ts, pwrdn_ts, residency);

 	/* Update CPU stats. */
 	psci_cpu_stat[cpu_idx][stat_idx].residency += residency;
 	psci_cpu_stat[cpu_idx][stat_idx].count++;

 	/*
 	 * Check what power domains above CPU were off
 	 * prior to this CPU powering on.
 	 */
 	parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;
 	for (lvl = PSCI_CPU_PWR_LVL + 1; lvl <= end_pwrlvl; lvl++) {
 		local_state = state_info->pwr_domain_state[lvl];
 		if (is_local_state_run(local_state)) {
 			/* Break early */
 			break;
 		}

 		assert(last_cpu_in_non_cpu_pd[parent_idx] != -1);

 		/* Get power down time-stamp for last CPU */
 		PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_ENTER_LOW_PWR,
 				last_cpu_in_non_cpu_pd[parent_idx],
 				flags, pwrdn_ts);

 		/* Initialize back to reset value */
 		last_cpu_in_non_cpu_pd[parent_idx] = -1;

 		/* Get the index into the stats array */
 		stat_idx = get_stat_idx(local_state, lvl);

 		/* Calculate stats residency */
 		calc_stat_residency(pwrup_ts, pwrdn_ts, residency);

 		/* Update non cpu stats */
 		psci_non_cpu_stat[parent_idx][stat_idx].residency += residency;
 		psci_non_cpu_stat[parent_idx][stat_idx].count++;

 		parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;
 	}

 }

 /*******************************************************************************
  * This function returns the appropriate count and residency time of the
  * local state for the highest power level expressed in the `power_state`
  * for the node represented by `target_cpu`.
  ******************************************************************************/
 int psci_get_stat(u_register_t target_cpu, unsigned int power_state,
 			 psci_stat_t *psci_stat)
 {
 	int rc, pwrlvl, lvl, parent_idx, stat_idx, target_idx;
 	psci_power_state_t state_info = { {PSCI_LOCAL_STATE_RUN} };
 	plat_local_state_t local_state;

 	/* Validate the target_cpu parameter and determine the cpu index */
 	target_idx = plat_core_pos_by_mpidr(target_cpu);
 	if (target_idx == -1)
 		return PSCI_E_INVALID_PARAMS;

 	/* Validate the power_state parameter */
 	if (!psci_plat_pm_ops->translate_power_state_by_mpidr)
 		rc = psci_validate_power_state(power_state, &state_info);
 	else
 		rc = psci_plat_pm_ops->translate_power_state_by_mpidr(
 				target_cpu, power_state, &state_info);

 	if (rc != PSCI_E_SUCCESS)
 		return PSCI_E_INVALID_PARAMS;

 	/* Find the highest power level */
 	pwrlvl = psci_find_target_suspend_lvl(&state_info);
 	if (pwrlvl == PSCI_INVALID_PWR_LVL) {
 		ERROR("Invalid target power level for PSCI statistics operation\n");
 		panic();
 	}

 	/* Get the index into the stats array */
 	local_state = state_info.pwr_domain_state[pwrlvl];
 	stat_idx = get_stat_idx(local_state, pwrlvl);

 	if (pwrlvl > PSCI_CPU_PWR_LVL) {
 		/* Get the power domain index */
 		parent_idx = psci_cpu_pd_nodes[target_idx].parent_node;
 		for (lvl = PSCI_CPU_PWR_LVL + 1; lvl < pwrlvl; lvl++)
 			parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;

 		/* Get the non cpu power domain stats */
 		*psci_stat = psci_non_cpu_stat[parent_idx][stat_idx];
 	} else {
 		/* Get the cpu power domain stats */
 		*psci_stat = psci_cpu_stat[target_idx][stat_idx];
 	}

 	return PSCI_E_SUCCESS;
 }

 /* This is the top level function for PSCI_STAT_RESIDENCY SMC. */
 u_register_t psci_stat_residency(u_register_t target_cpu,
 		unsigned int power_state)
 {
 	psci_stat_t psci_stat;

 	int rc = psci_get_stat(target_cpu, power_state, &psci_stat);
 	if (rc == PSCI_E_SUCCESS)
 		return psci_stat.residency;
 	else
 		return 0;
 }

 /* This is the top level function for PSCI_STAT_COUNT SMC. */
 u_register_t psci_stat_count(u_register_t target_cpu,
 	unsigned int power_state)
 {
 	psci_stat_t psci_stat;

 	int rc = psci_get_stat(target_cpu, power_state, &psci_stat);
 	if (rc == PSCI_E_SUCCESS)
 		return psci_stat.count;
 	else
 		return 0;
 }
	/*
	* Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* Redistributions of source code must retain the above copyright notice, this
	* list of conditions and the following disclaimer.
	*
	* Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	*
	* Neither the name of ARM nor the names of its contributors may be used
	* to endorse or promote products derived from this software without specific
	* prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	* POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <assert.h>
	#include <debug.h>
	#include <platform.h>
	#include <platform_def.h>
	#include "psci_private.h"

	#ifndef PLAT_MAX_PWR_LVL_STATES
	#define PLAT_MAX_PWR_LVL_STATES 2
	#endif

	/* Ticks elapsed in one second by a signal of 1 MHz */
	#define MHZ_TICKS_PER_SEC 1000000

	/* Following structure is used for PSCI STAT */
	typedef struct psci_stat {
	u_register_t residency;
	u_register_t count;
	} psci_stat_t;

	/*
	* Following is used to keep track of the last cpu
	* that goes to power down in non cpu power domains.
	*/
	static int last_cpu_in_non_cpu_pd[PSCI_NUM_NON_CPU_PWR_DOMAINS] = {-1};

	/*
	* Following are used to store PSCI STAT values for
	* CPU and non CPU power domains.
	*/
	static psci_stat_t psci_cpu_stat[PLATFORM_CORE_COUNT]
	[PLAT_MAX_PWR_LVL_STATES];
	static psci_stat_t psci_non_cpu_stat[PSCI_NUM_NON_CPU_PWR_DOMAINS]
	[PLAT_MAX_PWR_LVL_STATES];

	/* Register PMF PSCI service */
	PMF_REGISTER_SERVICE(psci_svc, PMF_PSCI_STAT_SVC_ID,
	PSCI_STAT_TOTAL_IDS, PMF_STORE_ENABLE)

	/* The divisor to use to convert raw timestamp into microseconds */
	u_register_t residency_div;

	/*
	* This macro calculates the stats residency in microseconds,
	* taking in account the wrap around condition.
	*/
	#define calc_stat_residency(_pwrupts, _pwrdnts, _res) \
	do { \
	if (_pwrupts < _pwrdnts) \
	_res = UINT64_MAX - _pwrdnts + _pwrupts;\
	else \
	_res = _pwrupts - _pwrdnts; \
	/* Convert timestamp into microseconds */ \
	_res = _res/residency_div; \
	} while (0)

	/*
	* This functions returns the index into the `psci_stat_t` array given the
	* local power state and power domain level. If the platform implements the
	* `get_pwr_lvl_state_idx` pm hook, then that will be used to return the index.
	*/
	static int get_stat_idx(plat_local_state_t local_state, int pwr_lvl)
	{
	int idx;

	if (psci_plat_pm_ops->get_pwr_lvl_state_idx == NULL) {
	assert(PLAT_MAX_PWR_LVL_STATES == 2);
	if (is_local_state_retn(local_state))
	return 0;

	assert(is_local_state_off(local_state));
	return 1;
	}

	idx = psci_plat_pm_ops->get_pwr_lvl_state_idx(local_state, pwr_lvl);
	assert((idx >= 0) && (idx < PLAT_MAX_PWR_LVL_STATES));
	return idx;
	}

	/*******************************************************************************
	* This function is passed the target local power states for each power
	* domain (state_info) between the current CPU domain and its ancestors until
	* the target power level (end_pwrlvl).
	*
	* Then, for each level (apart from the CPU level) until the 'end_pwrlvl', it
	* updates the `last_cpu_in_non_cpu_pd[]` with last power down cpu id.
	*
	* This function will only be invoked with data cache enabled and while
	* powering down a core.
	******************************************************************************/
	void psci_stats_update_pwr_down(unsigned int end_pwrlvl,
	const psci_power_state_t *state_info)
	{
	int lvl, parent_idx, cpu_idx = plat_my_core_pos();

	assert(end_pwrlvl <= PLAT_MAX_PWR_LVL);
	assert(state_info);

	parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;

	for (lvl = PSCI_CPU_PWR_LVL + 1; lvl <= end_pwrlvl; lvl++) {

	/* Break early if the target power state is RUN */
	if (is_local_state_run(state_info->pwr_domain_state[lvl]))
	break;

	/*
	* The power domain is entering a low power state, so this is
	* the last CPU for this power domain
	*/
	last_cpu_in_non_cpu_pd[parent_idx] = cpu_idx;

	parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;
	}

	}

	/*******************************************************************************
	* This function updates the PSCI STATS(residency time and count) for CPU
	* and NON-CPU power domains.
	* It is called with caches enabled and locks acquired(for NON-CPU domain)
	******************************************************************************/
	void psci_stats_update_pwr_up(unsigned int end_pwrlvl,
	const psci_power_state_t *state_info,
	unsigned int flags)
	{
	int parent_idx, cpu_idx = plat_my_core_pos();
	int lvl, stat_idx;
	plat_local_state_t local_state;
	unsigned long long pwrup_ts = 0, pwrdn_ts = 0;
	u_register_t residency;

	assert(end_pwrlvl <= PLAT_MAX_PWR_LVL);
	assert(state_info);

	/* Initialize the residency divisor if not already initialized */
	if (!residency_div) {
	/* Pre-calculate divisor so that it can be directly used to
	convert time-stamp into microseconds */
	residency_div = read_cntfrq_el0() / MHZ_TICKS_PER_SEC;
	assert(residency_div);
	}

	/* Get power down time-stamp for current CPU */
	PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_ENTER_LOW_PWR,
	cpu_idx, flags, pwrdn_ts);

	/* In the case of 1st power on just return */
	if (!pwrdn_ts)
	return;

	/* Get power up time-stamp for current CPU */
	PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_EXIT_LOW_PWR,
	cpu_idx, flags, pwrup_ts);

	/* Get the index into the stats array */
	local_state = state_info->pwr_domain_state[PSCI_CPU_PWR_LVL];
	stat_idx = get_stat_idx(local_state, PSCI_CPU_PWR_LVL);

	/* Calculate stats residency */
	calc_stat_residency(pwrup_ts, pwrdn_ts, residency);

	/* Update CPU stats. */
	psci_cpu_stat[cpu_idx][stat_idx].residency += residency;
	psci_cpu_stat[cpu_idx][stat_idx].count++;

	/*
	* Check what power domains above CPU were off
	* prior to this CPU powering on.
	*/
	parent_idx = psci_cpu_pd_nodes[cpu_idx].parent_node;
	for (lvl = PSCI_CPU_PWR_LVL + 1; lvl <= end_pwrlvl; lvl++) {
	local_state = state_info->pwr_domain_state[lvl];
	if (is_local_state_run(local_state)) {
	/* Break early */
	break;
	}

	assert(last_cpu_in_non_cpu_pd[parent_idx] != -1);

	/* Get power down time-stamp for last CPU */
	PMF_GET_TIMESTAMP_BY_INDEX(psci_svc, PSCI_STAT_ID_ENTER_LOW_PWR,
	last_cpu_in_non_cpu_pd[parent_idx],
	flags, pwrdn_ts);

	/* Initialize back to reset value */
	last_cpu_in_non_cpu_pd[parent_idx] = -1;

	/* Get the index into the stats array */
	stat_idx = get_stat_idx(local_state, lvl);

	/* Calculate stats residency */
	calc_stat_residency(pwrup_ts, pwrdn_ts, residency);

	/* Update non cpu stats */
	psci_non_cpu_stat[parent_idx][stat_idx].residency += residency;
	psci_non_cpu_stat[parent_idx][stat_idx].count++;

	parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;
	}

	}

	/*******************************************************************************
	* This function returns the appropriate count and residency time of the
	* local state for the highest power level expressed in the `power_state`
	* for the node represented by `target_cpu`.
	******************************************************************************/
	int psci_get_stat(u_register_t target_cpu, unsigned int power_state,
	psci_stat_t *psci_stat)
	{
	int rc, pwrlvl, lvl, parent_idx, stat_idx, target_idx;
	psci_power_state_t state_info = { {PSCI_LOCAL_STATE_RUN} };
	plat_local_state_t local_state;

	/* Validate the target_cpu parameter and determine the cpu index */
	target_idx = plat_core_pos_by_mpidr(target_cpu);
	if (target_idx == -1)
	return PSCI_E_INVALID_PARAMS;

	/* Validate the power_state parameter */
	if (!psci_plat_pm_ops->translate_power_state_by_mpidr)
	rc = psci_validate_power_state(power_state, &state_info);
	else
	rc = psci_plat_pm_ops->translate_power_state_by_mpidr(
	target_cpu, power_state, &state_info);

	if (rc != PSCI_E_SUCCESS)
	return PSCI_E_INVALID_PARAMS;

	/* Find the highest power level */
	pwrlvl = psci_find_target_suspend_lvl(&state_info);
	if (pwrlvl == PSCI_INVALID_PWR_LVL) {
	ERROR("Invalid target power level for PSCI statistics operation\n");
	panic();
	}

	/* Get the index into the stats array */
	local_state = state_info.pwr_domain_state[pwrlvl];
	stat_idx = get_stat_idx(local_state, pwrlvl);

	if (pwrlvl > PSCI_CPU_PWR_LVL) {
	/* Get the power domain index */
	parent_idx = psci_cpu_pd_nodes[target_idx].parent_node;
	for (lvl = PSCI_CPU_PWR_LVL + 1; lvl < pwrlvl; lvl++)
	parent_idx = psci_non_cpu_pd_nodes[parent_idx].parent_node;

	/* Get the non cpu power domain stats */
	*psci_stat = psci_non_cpu_stat[parent_idx][stat_idx];
	} else {
	/* Get the cpu power domain stats */
	*psci_stat = psci_cpu_stat[target_idx][stat_idx];
	}

	return PSCI_E_SUCCESS;
	}

	/* This is the top level function for PSCI_STAT_RESIDENCY SMC. */
	u_register_t psci_stat_residency(u_register_t target_cpu,
	unsigned int power_state)
	{
	psci_stat_t psci_stat;

	int rc = psci_get_stat(target_cpu, power_state, &psci_stat);
	if (rc == PSCI_E_SUCCESS)
	return psci_stat.residency;
	else
	return 0;
	}

	/* This is the top level function for PSCI_STAT_COUNT SMC. */
	u_register_t psci_stat_count(u_register_t target_cpu,
	unsigned int power_state)
	{
	psci_stat_t psci_stat;

	int rc = psci_get_stat(target_cpu, power_state, &psci_stat);
	if (rc == PSCI_E_SUCCESS)
	return psci_stat.count;
	else
	return 0;
	}