arch/powerpc/kernel/idle.c

Source file repositories/reference/linux-study-clean/arch/powerpc/kernel/idle.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/kernel/idle.c
Extension
.c
Size
2527 bytes
Lines
119
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Idle daemon for PowerPC.  Idle daemon will handle any action
 * that needs to be taken when the system becomes idle.
 *
 * Originally written by Cort Dougan (cort@cs.nmt.edu).
 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
 * Paul Mackerras and others.
 *
 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
 *
 * Additional shared processor, SMT, and firmware support
 *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
 *
 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/sysctl.h>
#include <linux/tick.h>

#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/runlatch.h>
#include <asm/smp.h>


unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
EXPORT_SYMBOL(cpuidle_disable);

static int __init powersave_off(char *arg)
{
	ppc_md.power_save = NULL;
	cpuidle_disable = IDLE_POWERSAVE_OFF;
	return 1;
}
__setup("powersave=off", powersave_off);

void arch_cpu_idle(void)
{
	ppc64_runlatch_off();

	if (ppc_md.power_save) {
		ppc_md.power_save();
		/*
		 * Some power_save functions return with
		 * interrupts enabled, some don't.
		 */
		if (!irqs_disabled())
			raw_local_irq_disable();
	} else {
		/*
		 * Go into low thread priority and possibly
		 * low power mode.
		 */
		HMT_low();
		HMT_very_low();
	}

	HMT_medium();
	ppc64_runlatch_on();
}

int powersave_nap;

#ifdef CONFIG_PPC_970_NAP
void power4_idle(void)
{
	if (!cpu_has_feature(CPU_FTR_CAN_NAP))
		return;

	if (!powersave_nap)
		return;

	if (!prep_irq_for_idle())
		return;

	if (cpu_has_feature(CPU_FTR_ALTIVEC))
		asm volatile(PPC_DSSALL " ; sync" ::: "memory");

	power4_idle_nap();

	/*
	 * power4_idle_nap returns with interrupts enabled (soft and hard).
	 * to our caller with interrupts enabled (soft and hard). Our caller

Annotation

Implementation Notes