Fix for KVMFORNFV-23(Fuel installed KVM kernel blank screens on boot).
[kvmfornfv.git] / kernel / arch / arm / mach-tegra / cpuidle-tegra30.c
1 /*
2  * CPU idle driver for Tegra CPUs
3  *
4  * Copyright (c) 2010-2012, NVIDIA Corporation.
5  * Copyright (c) 2011 Google, Inc.
6  * Author: Colin Cross <ccross@android.com>
7  *         Gary King <gking@nvidia.com>
8  *
9  * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful, but WITHOUT
17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
19  * more details.
20  */
21
22 #include <linux/clk/tegra.h>
23 #include <linux/tick.h>
24 #include <linux/cpuidle.h>
25 #include <linux/cpu_pm.h>
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28
29 #include <asm/cpuidle.h>
30 #include <asm/smp_plat.h>
31 #include <asm/suspend.h>
32
33 #include "pm.h"
34 #include "sleep.h"
35
36 #ifdef CONFIG_PM_SLEEP
37 static int tegra30_idle_lp2(struct cpuidle_device *dev,
38                             struct cpuidle_driver *drv,
39                             int index);
40 #endif
41
42 static struct cpuidle_driver tegra_idle_driver = {
43         .name = "tegra_idle",
44         .owner = THIS_MODULE,
45 #ifdef CONFIG_PM_SLEEP
46         .state_count = 2,
47 #else
48         .state_count = 1,
49 #endif
50         .states = {
51                 [0] = ARM_CPUIDLE_WFI_STATE_PWR(600),
52 #ifdef CONFIG_PM_SLEEP
53                 [1] = {
54                         .enter                  = tegra30_idle_lp2,
55                         .exit_latency           = 2000,
56                         .target_residency       = 2200,
57                         .power_usage            = 0,
58                         .name                   = "powered-down",
59                         .desc                   = "CPU power gated",
60                 },
61 #endif
62         },
63 };
64
65 #ifdef CONFIG_PM_SLEEP
66 static bool tegra30_cpu_cluster_power_down(struct cpuidle_device *dev,
67                                            struct cpuidle_driver *drv,
68                                            int index)
69 {
70         /* All CPUs entering LP2 is not working.
71          * Don't let CPU0 enter LP2 when any secondary CPU is online.
72          */
73         if (num_online_cpus() > 1 || !tegra_cpu_rail_off_ready()) {
74                 cpu_do_idle();
75                 return false;
76         }
77
78         tick_broadcast_enter();
79
80         tegra_idle_lp2_last();
81
82         tick_broadcast_exit();
83
84         return true;
85 }
86
87 #ifdef CONFIG_SMP
88 static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
89                                         struct cpuidle_driver *drv,
90                                         int index)
91 {
92         tick_broadcast_enter();
93
94         smp_wmb();
95
96         cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
97
98         tick_broadcast_exit();
99
100         return true;
101 }
102 #else
103 static inline bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
104                                                struct cpuidle_driver *drv,
105                                                int index)
106 {
107         return true;
108 }
109 #endif
110
111 static int tegra30_idle_lp2(struct cpuidle_device *dev,
112                             struct cpuidle_driver *drv,
113                             int index)
114 {
115         bool entered_lp2 = false;
116         bool last_cpu;
117
118         local_fiq_disable();
119
120         last_cpu = tegra_set_cpu_in_lp2();
121         cpu_pm_enter();
122
123         if (dev->cpu == 0) {
124                 if (last_cpu)
125                         entered_lp2 = tegra30_cpu_cluster_power_down(dev, drv,
126                                                                      index);
127                 else
128                         cpu_do_idle();
129         } else {
130                 entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);
131         }
132
133         cpu_pm_exit();
134         tegra_clear_cpu_in_lp2();
135
136         local_fiq_enable();
137
138         smp_rmb();
139
140         return (entered_lp2) ? index : 0;
141 }
142 #endif
143
144 int __init tegra30_cpuidle_init(void)
145 {
146         return cpuidle_register(&tegra_idle_driver, NULL);
147 }