Linux Kernel  3.7.1
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idle.c
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1 /*
2  * Copyright (C) 2006-2007 PA Semi, Inc
3  *
4  * Maintained by: Olof Johansson <[email protected]>
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;
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_WAKEEE:
57  do_IRQ(regs);
58  break;
59  case SRR1_WAKEDEC:
60  timer_interrupt(regs);
61  break;
62  default:
63  /* do system reset */
64  return 0;
65  }
66 
67  /* Set higher astate since we come out of power savings at 0 */
69 
70  /* everything handled */
71  regs->msr |= MSR_RI;
72  return 1;
73 }
74 
75 static int __init pasemi_idle_init(void)
76 {
77 #ifndef CONFIG_PPC_PASEMI_CPUFREQ
78  printk(KERN_WARNING "No cpufreq driver, powersavings modes disabled\n");
79  current_mode = 0;
80 #endif
81 
82  ppc_md.system_reset_exception = pasemi_system_reset_exception;
83  ppc_md.power_save = modes[current_mode].entry;
84  printk(KERN_INFO "Using PA6T idle loop (%s)\n", modes[current_mode].name);
85 
86  return 0;
87 }
88 machine_late_initcall(pasemi, pasemi_idle_init);
89 
90 static int __init idle_param(char *p)
91 {
92  int i;
93  for (i = 0; i < ARRAY_SIZE(modes); i++) {
94  if (!strcmp(modes[i].name, p)) {
95  current_mode = i;
96  break;
97  }
98  }
99  return 0;
100 }
101 
102 early_param("idle", idle_param);