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review.shift-gmbh.com / SHIFTPHONES / kernel / common / c46fff2a3b29794b35d717b5680a27f31a6a6bc0 / . / drivers / cpuidle / cpuidle-powernv.c
blob: 78fd174c57e86dfb4608a12f4af44d334ab1da7c [file] [log] [blame]
Deepthi Dharwar2c2e6ec2014-01-14 16:32:40 +0530[diff] [blame]1/*
2 * cpuidle-powernv - idle state cpuidle driver.
3 * Adapted from drivers/cpuidle/cpuidle-pseries
4 *
5 */
6
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/moduleparam.h>
11#include <linux/cpuidle.h>
12#include <linux/cpu.h>
13#include <linux/notifier.h>
14
15#include <asm/machdep.h>
16#include <asm/firmware.h>
17
18struct cpuidle_driver powernv_idle_driver = {
19 .name = "powernv_idle",
20 .owner = THIS_MODULE,
21};
22
23static int max_idle_state;
24static struct cpuidle_state *cpuidle_state_table;
25
26static int snooze_loop(struct cpuidle_device *dev,
27 struct cpuidle_driver *drv,
28 int index)
29{
30 local_irq_enable();
31 set_thread_flag(TIF_POLLING_NRFLAG);
32
33 while (!need_resched()) {
34 HMT_low();
35 HMT_very_low();
36 }
37
38 HMT_medium();
39 clear_thread_flag(TIF_POLLING_NRFLAG);
40 smp_mb();
41 return index;
42}
43
44static int nap_loop(struct cpuidle_device *dev,
45 struct cpuidle_driver *drv,
46 int index)
47{
48 power7_idle();
49 return index;
50}
51
52/*
53 * States for dedicated partition case.
54 */
55static struct cpuidle_state powernv_states[] = {
56 { /* Snooze */
57 .name = "snooze",
58 .desc = "snooze",
59 .flags = CPUIDLE_FLAG_TIME_VALID,
60 .exit_latency = 0,
61 .target_residency = 0,
62 .enter = &snooze_loop },
63 { /* NAP */
64 .name = "NAP",
65 .desc = "NAP",
66 .flags = CPUIDLE_FLAG_TIME_VALID,
67 .exit_latency = 10,
68 .target_residency = 100,
69 .enter = &nap_loop },
70};
71
72static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
73 unsigned long action, void *hcpu)
74{
75 int hotcpu = (unsigned long)hcpu;
76 struct cpuidle_device *dev =
77 per_cpu(cpuidle_devices, hotcpu);
78
79 if (dev && cpuidle_get_driver()) {
80 switch (action) {
81 case CPU_ONLINE:
82 case CPU_ONLINE_FROZEN:
83 cpuidle_pause_and_lock();
84 cpuidle_enable_device(dev);
85 cpuidle_resume_and_unlock();
86 break;
87
88 case CPU_DEAD:
89 case CPU_DEAD_FROZEN:
90 cpuidle_pause_and_lock();
91 cpuidle_disable_device(dev);
92 cpuidle_resume_and_unlock();
93 break;
94
95 default:
96 return NOTIFY_DONE;
97 }
98 }
99 return NOTIFY_OK;
100}
101
102static struct notifier_block setup_hotplug_notifier = {
103 .notifier_call = powernv_cpuidle_add_cpu_notifier,
104};
105
106/*
107 * powernv_cpuidle_driver_init()
108 */
109static int powernv_cpuidle_driver_init(void)
110{
111 int idle_state;
112 struct cpuidle_driver *drv = &powernv_idle_driver;
113
114 drv->state_count = 0;
115
116 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
117 /* Is the state not enabled? */
118 if (cpuidle_state_table[idle_state].enter == NULL)
119 continue;
120
121 drv->states[drv->state_count] = /* structure copy */
122 cpuidle_state_table[idle_state];
123
124 drv->state_count += 1;
125 }
126
127 return 0;
128}
129
130/*
131 * powernv_idle_probe()
132 * Choose state table for shared versus dedicated partition
133 */
134static int powernv_idle_probe(void)
135{
136
137 if (cpuidle_disable != IDLE_NO_OVERRIDE)
138 return -ENODEV;
139
140 if (firmware_has_feature(FW_FEATURE_OPALv3)) {
141 cpuidle_state_table = powernv_states;
142 max_idle_state = ARRAY_SIZE(powernv_states);
143 } else
144 return -ENODEV;
145
146 return 0;
147}
148
149static int __init powernv_processor_idle_init(void)
150{
151 int retval;
152
153 retval = powernv_idle_probe();
154 if (retval)
155 return retval;
156
157 powernv_cpuidle_driver_init();
158 retval = cpuidle_register(&powernv_idle_driver, NULL);
159 if (retval) {
160 printk(KERN_DEBUG "Registration of powernv driver failed.\n");
161 return retval;
162 }
163
164 register_cpu_notifier(&setup_hotplug_notifier);
165 printk(KERN_DEBUG "powernv_idle_driver registered\n");
166 return 0;
167}
168
169device_initcall(powernv_processor_idle_init);