source: rtems/c/src/lib/libbsp/arm/atsam/startup/power.c @ 5d0f0de4

/*
 * Copyright (c) 2016 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Dornierstr. 4
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#include <bsp.h>
#include <bsp/power.h>
#include <bsp/irq.h>

#include <libchip/chip.h>

/* SCR Sleep deep bit */
#define SCR_SLEEPDEEP (1u << 2)

void atsam_power_change_state(
    const atsam_power_control *controls,
    size_t n,
    atsam_power_state state
)
{
        size_t i;

        switch (state) {
                case ATSAM_POWER_ON:
                        for (i = n; i > 0; --i) {
                                const atsam_power_control *c;

                                c = &controls[i - 1];
                                (*c->handler)(c, state);
                        }

                        break;
                case ATSAM_POWER_INIT:
                case ATSAM_POWER_OFF:
                        for (i = 0; i < n; ++i) {
                                const atsam_power_control *c;

                                c = &controls[i];
                                (*c->handler)(c, state);
                        }

                        break;
                default:
                        break;
        }
}

void atsam_power_handler_peripheral(
    const atsam_power_control *control,
    atsam_power_state state
)
{
        uint32_t id;
        uint32_t end;

        id = control->data.peripherals.first;
        end = control->data.peripherals.last + 1;

        switch (state) {
                case ATSAM_POWER_ON:
                        while (id != end) {
                                PMC_EnablePeripheral(id);
                                ++id;
                        }
                        break;
                case ATSAM_POWER_OFF:
                        while (id != end) {
                                PMC_DisablePeripheral(id);
                                ++id;
                        }
                        break;
                default:
                        break;
        }
}

void atsam_power_handler_sleep_mode(const atsam_power_control *control, atsam_power_state state)
{
        (void) control;

        switch (state) {
                case ATSAM_POWER_OFF:
                        /* Enable Low Power Mode in the Fast Startup Mode Register */
                        PMC->PMC_FSMR &= (uint32_t)~PMC_FSMR_LPM;
                        /* Do not set deep sleep, but "normal" sleep */
                        SCB->SCR &= (uint32_t)~SCR_SLEEPDEEP;

                        __asm__ volatile ("wfi");
                        break;
                default:
                        break;
        }
}