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// SPDX-License-Identifier: GPL-2.0-only
/*
* Low-level idle sequences
*/
#include <linux/cpu.h>
#include <linux/irqflags.h>
#include <asm/barrier.h>
#include <asm/cpuidle.h>
#include <asm/cpufeature.h>
#include <asm/sysreg.h>
enum {
ARM64_IDLE_WFI,
ARM64_IDLE_YIELD,
ARM64_IDLE_NOP,
} idle = ARM64_IDLE_WFI;
static int __init setup_idle(char *arg)
{
if (!arg)
return -1;
else if (!strcmp(arg, "wfi"))
idle = ARM64_IDLE_WFI;
else if (!strcmp(arg, "yield"))
idle = ARM64_IDLE_YIELD;
else if (!strcmp(arg, "nop"))
idle = ARM64_IDLE_NOP;
else
return -1;
return 0;
}
early_param("idle", setup_idle);
/*
* cpu_do_idle()
*
* Idle the processor (wait for interrupt).
*
* If the CPU supports priority masking we must do additional work to
* ensure that interrupts are not masked at the PMR (because the core will
* not wake up if we block the wake up signal in the interrupt controller).
*/
void __cpuidle cpu_do_idle(void)
{
struct arm_cpuidle_irq_context context;
arm_cpuidle_save_irq_context(&context);
if (likely(idle == ARM64_IDLE_WFI)) {
dsb(sy);
wfi();
} else if (idle == ARM64_IDLE_YIELD) {
dsb(sy);
asm volatile("yield" ::: "memory");
}
arm_cpuidle_restore_irq_context(&context);
}
/*
* This is our default idle handler.
*/
void __cpuidle arch_cpu_idle(void)
{
/*
* This should do all the clock switching and wait for interrupt
* tricks
*/
cpu_do_idle();
}
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