idle.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright 2008 IBM Corp. 
 4 *
 5 * Based on arch/powerpc/platforms/pasemi/idle.c: 
 6 * Copyright (C) 2006-2007 PA Semi, Inc
 7 *
 8 * Added by: Jerone Young <jyoung5@us.ibm.com>
 9 */
10
11#include <linux/of.h>
12#include <linux/kernel.h>
13#include <asm/machdep.h>
14
15static int mode_spin;
16
17static void ppc44x_idle(void)
18{
19	unsigned long msr_save;
20
21	msr_save = mfmsr();
22	/* set wait state MSR */
23	mtmsr(msr_save|MSR_WE|MSR_EE|MSR_CE|MSR_DE);
24	isync();
25	/* return to initial state */
26	mtmsr(msr_save);
27	isync();
28}
29
30static int __init ppc44x_idle_init(void)
31{
32	if (!mode_spin) {
33		/* If we are not setting spin mode 
34                   then we set to wait mode */
35		ppc_md.power_save = &ppc44x_idle;
36	}
37
38	return 0;
39}
40
41arch_initcall(ppc44x_idle_init);
42
43static int __init idle_param(char *p)
44{ 
45
46	if (!strcmp("spin", p)) {
47		mode_spin = 1;
48		ppc_md.power_save = NULL;
49	}
50
51	return 0;
52}
53
54early_param("idle", idle_param);