zephyr/soc/riscv32/pulpino/pulpino_idle.c

63 lines
1.4 KiB
C

/*
* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <toolchain.h>
#include <irq.h>
#include <soc.h>
#include <tracing.h>
static ALWAYS_INLINE void pulpino_idle(unsigned int key)
{
z_sys_trace_idle();
/* unlock interrupts */
irq_unlock(key);
/* Put CPU core to sleep via SCR register */
PULP_SCR = 0x01;
/* Wait for interrupt */
SOC_WFI;
}
/**
*
* @brief Power save idle routine
*
* This function will be called by the kernel idle loop or possibly within
* an implementation of _sys_power_save_idle in the kernel when the
* '_sys_power_save_flag' variable is non-zero.
*
* @return N/A
*/
void k_cpu_idle(void)
{
pulpino_idle(SOC_MSTATUS_IEN);
}
/**
*
* @brief Atomically re-enable interrupts and enter low power mode
*
* INTERNAL
* The requirements for k_cpu_atomic_idle() are as follows:
* 1) The enablement of interrupts and entering a low-power mode needs to be
* atomic, i.e. there should be no period of time where interrupts are
* enabled before the processor enters a low-power mode. See the comments
* in k_lifo_get(), for example, of the race condition that
* occurs if this requirement is not met.
*
* 2) After waking up from the low-power mode, the interrupt lockout state
* must be restored as indicated in the 'imask' input parameter.
*
* @return N/A
*/
void k_cpu_atomic_idle(unsigned int key)
{
pulpino_idle(key);
}