zephyr/soc/arm/microchip_mec/mec1501/power.c

140 lines
3.4 KiB
C

/*
* Copyright (c) 2019 Microchip Technology Inc.
* Copyright (c) 2016 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr.h>
#include <sys/sys_io.h>
#include <sys/__assert.h>
#include <pm/pm.h>
#include <soc.h>
#include "device_power.h"
/*
* Deep Sleep
* Pros:
* Lower power dissipation, 48MHz PLL is off
* Cons:
* Longer wake latency. CPU start running on ring oscillator
* between 16 to 25 MHz. Minimum 3ms until PLL reaches lock
* frequency of 48MHz.
*
* Implementation Notes:
* We touch the Cortex-M's primary mask and base priority registers
* because we do not want to enter an ISR immediately upon wake.
* We must restore any hardware state that was modified upon sleep
* entry before allowing interrupts to be serviced. Zephyr arch level
* does not provide API's to manipulate both primary mask and base priority.
*
* DEBUG NOTES:
* If a JTAG/SWD debug probe is connected driving TRST# high and
* possibly polling the DUT then MEC1501 will not shut off its 48MHz
* PLL. Firmware should not disable JTAG/SWD in the EC subsystem
* while a probe is using the interface. This can leave the JTAG/SWD
* TAP controller in a state of requesting clocks preventing the PLL
* from being shut off.
*/
static void z_power_soc_deep_sleep(void)
{
/* Mask all exceptions and interrupts except NMI and HardFault */
__set_PRIMASK(1);
soc_deep_sleep_periph_save();
soc_deep_sleep_enable();
soc_deep_sleep_wait_clk_idle();
soc_deep_sleep_non_wake_en();
/*
* Unmask all interrupts in BASEPRI. PRIMASK is used above to
* prevent entering an ISR after unmasking in BASEPRI.
*/
__set_BASEPRI(0);
__DSB();
__WFI(); /* triggers sleep hardware */
__NOP();
__NOP();
soc_deep_sleep_disable();
soc_deep_sleep_non_wake_dis();
/* Wait for PLL to lock */
while ((PCR_REGS->OSC_ID & MCHP_PCR_OSC_ID_PLL_LOCK) == 0) {
}
soc_deep_sleep_periph_restore();
/*
* pm_power_state_exit_post_ops() is not being called
* after exiting deep sleep, so need to unmask exceptions
* and interrupts here.
*/
__set_PRIMASK(0);
}
/*
* Light Sleep
* Pros:
* Fast wake response:
* Cons:
* Higher power dissipation, 48MHz PLL remains on.
*/
static void z_power_soc_sleep(void)
{
__set_PRIMASK(1);
soc_lite_sleep_enable();
__set_BASEPRI(0); /* Make sure wake interrupts are not masked! */
__DSB();
__WFI(); /* triggers sleep hardware */
__NOP();
__NOP();
}
/*
* Called from pm_system_suspend(int32_t ticks) in subsys/power.c
* For deep sleep pm_system_suspend has executed all the driver
* power management call backs.
*/
void pm_power_state_set(struct pm_state_info info)
{
switch (info.state) {
case PM_STATE_SUSPEND_TO_IDLE:
z_power_soc_sleep();
break;
case PM_STATE_SUSPEND_TO_RAM:
z_power_soc_deep_sleep();
break;
default:
break;
}
}
/*
* Zephyr PM code expects us to enabled interrupts at post op exit. Zephyr used
* arch_irq_lock() which sets BASEPRI to a non-zero value masking all interrupts
* preventing wake. MCHP z_power_soc_(deep)_sleep sets PRIMASK=1 and BASEPRI=0
* allowing wake from any enabled interrupt and prevents the CPU from entering
* an ISR on wake except for faults. We re-enable interrupts by setting PRIMASK
* to 0.
*/
void pm_power_state_exit_post_ops(struct pm_state_info info)
{
switch (info.state) {
case PM_STATE_SUSPEND_TO_IDLE:
case PM_STATE_SUSPEND_TO_RAM:
__set_PRIMASK(0);
__ISB();
break;
default:
irq_unlock(0);
break;
}
}