1 /*
2  * Copyright (C) 2006-2007 PA Semi, Inc
3  *
4  * Maintained by: Olof Johansson <olof@lixom.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18  *
19  */
20 
21 #undef DEBUG
22 
23 #include <linux/kernel.h>
24 #include <linux/string.h>
25 #include <linux/irq.h>
26 
27 #include <asm/machdep.h>
28 #include <asm/reg.h>
29 #include <asm/smp.h>
30 
31 #include "pasemi.h"
32 
33 struct sleep_mode {
34 	char *name;
35 	void (*entry)(void);
36 };
37 
38 static struct sleep_mode modes[] = {
39 	{ .name = "spin", .entry = &idle_spin },
40 	{ .name = "doze", .entry = &idle_doze },
41 };
42 
43 static int current_mode = 0;
44 
45 static int pasemi_system_reset_exception(struct pt_regs *regs)
46 {
47 	/* If we were woken up from power savings, we need to return
48 	 * to the calling function, since nip is not saved across
49 	 * all modes.
50 	 */
51 
52 	if (regs->msr & SRR1_WAKEMASK)
53 		regs->nip = regs->link;
54 
55 	switch (regs->msr & SRR1_WAKEMASK) {
56 	case SRR1_WAKEDEC:
57 		set_dec(1);
58 	case SRR1_WAKEEE:
59 		/*
60 		 * Handle these when interrupts get re-enabled and we take
61 		 * them as regular exceptions. We are in an NMI context
62 		 * and can't handle these here.
63 		 */
64 		break;
65 	default:
66 		/* do system reset */
67 		return 0;
68 	}
69 
70 	/* Set higher astate since we come out of power savings at 0 */
71 	restore_astate(hard_smp_processor_id());
72 
73 	/* everything handled */
74 	regs->msr |= MSR_RI;
75 	return 1;
76 }
77 
78 static int __init pasemi_idle_init(void)
79 {
80 #ifndef CONFIG_PPC_PASEMI_CPUFREQ
81 	pr_warn("No cpufreq driver, powersavings modes disabled\n");
82 	current_mode = 0;
83 #endif
84 
85 	ppc_md.system_reset_exception = pasemi_system_reset_exception;
86 	ppc_md.power_save = modes[current_mode].entry;
87 	pr_info("Using PA6T idle loop (%s)\n", modes[current_mode].name);
88 
89 	return 0;
90 }
91 machine_late_initcall(pasemi, pasemi_idle_init);
92 
93 static int __init idle_param(char *p)
94 {
95 	int i;
96 	for (i = 0; i < ARRAY_SIZE(modes); i++) {
97 		if (!strcmp(modes[i].name, p)) {
98 			current_mode = i;
99 			break;
100 		}
101 	}
102 	return 0;
103 }
104 
105 early_param("idle", idle_param);
106