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 "cpuidle.h"
34 #include "pm.h"
35 #include "sleep.h"
36
37 #ifdef CONFIG_PM_SLEEP
38 static int tegra30_idle_lp2(struct cpuidle_device *dev,
39 struct cpuidle_driver *drv,
40 int index);
41 #endif
42
43 static struct cpuidle_driver tegra_idle_driver = {
44 .name = "tegra_idle",
45 .owner = THIS_MODULE,
46 #ifdef CONFIG_PM_SLEEP
47 .state_count = 2,
48 #else
49 .state_count = 1,
50 #endif
51 .states = {
52 [0] = ARM_CPUIDLE_WFI_STATE_PWR(600),
53 #ifdef CONFIG_PM_SLEEP
54 [1] = {
55 .enter = tegra30_idle_lp2,
56 .exit_latency = 2000,
57 .target_residency = 2200,
58 .power_usage = 0,
59 .name = "powered-down",
60 .desc = "CPU power gated",
61 },
62 #endif
63 },
64 };
65
66 #ifdef CONFIG_PM_SLEEP
tegra30_cpu_cluster_power_down(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)67 static bool tegra30_cpu_cluster_power_down(struct cpuidle_device *dev,
68 struct cpuidle_driver *drv,
69 int index)
70 {
71 /* All CPUs entering LP2 is not working.
72 * Don't let CPU0 enter LP2 when any secondary CPU is online.
73 */
74 if (num_online_cpus() > 1 || !tegra_cpu_rail_off_ready()) {
75 cpu_do_idle();
76 return false;
77 }
78
79 tick_broadcast_enter();
80
81 tegra_idle_lp2_last();
82
83 tick_broadcast_exit();
84
85 return true;
86 }
87
88 #ifdef CONFIG_SMP
tegra30_cpu_core_power_down(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)89 static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
90 struct cpuidle_driver *drv,
91 int index)
92 {
93 tick_broadcast_enter();
94
95 smp_wmb();
96
97 cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
98
99 tick_broadcast_exit();
100
101 return true;
102 }
103 #else
tegra30_cpu_core_power_down(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)104 static inline bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
105 struct cpuidle_driver *drv,
106 int index)
107 {
108 return true;
109 }
110 #endif
111
tegra30_idle_lp2(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)112 static int tegra30_idle_lp2(struct cpuidle_device *dev,
113 struct cpuidle_driver *drv,
114 int index)
115 {
116 bool entered_lp2 = false;
117 bool last_cpu;
118
119 local_fiq_disable();
120
121 last_cpu = tegra_set_cpu_in_lp2();
122 cpu_pm_enter();
123
124 if (dev->cpu == 0) {
125 if (last_cpu)
126 entered_lp2 = tegra30_cpu_cluster_power_down(dev, drv,
127 index);
128 else
129 cpu_do_idle();
130 } else {
131 entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);
132 }
133
134 cpu_pm_exit();
135 tegra_clear_cpu_in_lp2();
136
137 local_fiq_enable();
138
139 smp_rmb();
140
141 return (entered_lp2) ? index : 0;
142 }
143 #endif
144
tegra30_cpuidle_init(void)145 int __init tegra30_cpuidle_init(void)
146 {
147 return cpuidle_register(&tegra_idle_driver, NULL);
148 }
149
