arm_pm.c

/*
 * Copyright (c) 2015, 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 <arch_helpers.h>
#include <assert.h>
#include <errno.h>
#include <psci.h>


/*******************************************************************************
 * ARM standard platform utility function which is used to determine if any
 * platform actions should be performed for the specified affinity instance
 * given its state. Nothing needs to be done if the 'state' is not off or if
 * this is not the highest affinity level which will enter the 'state'.
 ******************************************************************************/
int32_t arm_do_affinst_actions(unsigned int afflvl, unsigned int state)
{
	unsigned int max_phys_off_afflvl;

	assert(afflvl <= MPIDR_AFFLVL1);

	if (state != PSCI_STATE_OFF)
		return -EAGAIN;

	/*
	 * Find the highest affinity level which will be suspended and postpone
	 * all the platform specific actions until that level is hit.
	 */
	max_phys_off_afflvl = psci_get_max_phys_off_afflvl();
	assert(max_phys_off_afflvl != PSCI_INVALID_DATA);
	if (afflvl != max_phys_off_afflvl)
		return -EAGAIN;

	return 0;
}

/*******************************************************************************
 * ARM standard platform handler called to check the validity of the power state
 * parameter.
 ******************************************************************************/
int arm_validate_power_state(unsigned int power_state)
{
	/* Sanity check the requested state */
	if (psci_get_pstate_type(power_state) == PSTATE_TYPE_STANDBY) {
		/*
		 * It's possible to enter standby only on affinity level 0
		 * (i.e. a CPU on ARM standard platforms).
		 * Ignore any other affinity level.
		 */
		if (psci_get_pstate_afflvl(power_state) != MPIDR_AFFLVL0)
			return PSCI_E_INVALID_PARAMS;
	}

	/*
	 * We expect the 'state id' to be zero.
	 */
	if (psci_get_pstate_id(power_state))
		return PSCI_E_INVALID_PARAMS;

	return PSCI_E_SUCCESS;
}