1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2006-2007 PA Semi, Inc
4 *
5 * Maintained by: Olof Johansson <olof@lixom.net>
6 */
7
8#undef DEBUG
9
10#include <linux/kernel.h>
11#include <linux/string.h>
12#include <linux/irq.h>
13
14#include <asm/machdep.h>
15#include <asm/reg.h>
16#include <asm/smp.h>
17
18#include "pasemi.h"
19
20struct sleep_mode {
21	char *name;
22	void (*entry)(void);
23};
24
25static struct sleep_mode modes[] = {
26	{ .name = "spin", .entry = &idle_spin },
27	{ .name = "doze", .entry = &idle_doze },
28};
29
30static int current_mode = 0;
31
32static int pasemi_system_reset_exception(struct pt_regs *regs)
33{
34	/* If we were woken up from power savings, we need to return
35	 * to the calling function, since nip is not saved across
36	 * all modes.
37	 */
38
39	if (regs->msr & SRR1_WAKEMASK)
40		regs->nip = regs->link;
41
42	switch (regs->msr & SRR1_WAKEMASK) {
43	case SRR1_WAKEDEC:
44		set_dec(1);
45	case SRR1_WAKEEE:
46		/*
47		 * Handle these when interrupts get re-enabled and we take
48		 * them as regular exceptions. We are in an NMI context
49		 * and can't handle these here.
50		 */
51		break;
52	default:
53		/* do system reset */
54		return 0;
55	}
56
57	/* Set higher astate since we come out of power savings at 0 */
58	restore_astate(hard_smp_processor_id());
59
60	/* everything handled */
61	regs->msr |= MSR_RI;
62	return 1;
63}
64
65static int __init pasemi_idle_init(void)
66{
67#ifndef CONFIG_PPC_PASEMI_CPUFREQ
68	pr_warn("No cpufreq driver, powersavings modes disabled\n");
69	current_mode = 0;
70#endif
71
72	ppc_md.system_reset_exception = pasemi_system_reset_exception;
73	ppc_md.power_save = modes[current_mode].entry;
74	pr_info("Using PA6T idle loop (%s)\n", modes[current_mode].name);
75
76	return 0;
77}
78machine_late_initcall(pasemi, pasemi_idle_init);
79
80static int __init idle_param(char *p)
81{
82	int i;
83	for (i = 0; i < ARRAY_SIZE(modes); i++) {
84		if (!strcmp(modes[i].name, p)) {
85			current_mode = i;
86			break;
87		}
88	}
89	return 0;
90}
91
92early_param("idle", idle_param);
93