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 
15 static int mode_spin;
16 
ppc44x_idle(void)17 static 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 
ppc44x_idle_init(void)30 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 
41 arch_initcall(ppc44x_idle_init);
42 
idle_param(char * p)43 static 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 
54 early_param("idle", idle_param);
55