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
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
30 static 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
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
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