Commit | Line | Data |
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4f86d3a8 LB |
1 | /* |
2 | * governor.c - governor support | |
3 | * | |
4 | * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | |
5 | * Shaohua Li <shaohua.li@intel.com> | |
6 | * Adam Belay <abelay@novell.com> | |
7 | * | |
8 | * This code is licenced under the GPL. | |
9 | */ | |
10 | ||
0fc784fb | 11 | #include <linux/cpu.h> |
4f86d3a8 | 12 | #include <linux/cpuidle.h> |
0fc784fb | 13 | #include <linux/mutex.h> |
61cb5758 | 14 | #include <linux/module.h> |
0fc784fb | 15 | #include <linux/pm_qos.h> |
4f86d3a8 LB |
16 | |
17 | #include "cpuidle.h" | |
18 | ||
61cb5758 RW |
19 | char param_governor[CPUIDLE_NAME_LEN]; |
20 | ||
4f86d3a8 LB |
21 | LIST_HEAD(cpuidle_governors); |
22 | struct cpuidle_governor *cpuidle_curr_governor; | |
23 | ||
24 | /** | |
25 | * __cpuidle_find_governor - finds a governor of the specified name | |
26 | * @str: the name | |
27 | * | |
21ae2956 | 28 | * Must be called with cpuidle_lock acquired. |
4f86d3a8 LB |
29 | */ |
30 | static struct cpuidle_governor * __cpuidle_find_governor(const char *str) | |
31 | { | |
32 | struct cpuidle_governor *gov; | |
33 | ||
34 | list_for_each_entry(gov, &cpuidle_governors, governor_list) | |
91336640 | 35 | if (!strncasecmp(str, gov->name, CPUIDLE_NAME_LEN)) |
4f86d3a8 LB |
36 | return gov; |
37 | ||
38 | return NULL; | |
39 | } | |
40 | ||
41 | /** | |
42 | * cpuidle_switch_governor - changes the governor | |
43 | * @gov: the new target governor | |
21ae2956 | 44 | * Must be called with cpuidle_lock acquired. |
4f86d3a8 LB |
45 | */ |
46 | int cpuidle_switch_governor(struct cpuidle_governor *gov) | |
47 | { | |
48 | struct cpuidle_device *dev; | |
49 | ||
3cfd68b5 | 50 | if (!gov) |
51 | return -EINVAL; | |
52 | ||
4f86d3a8 LB |
53 | if (gov == cpuidle_curr_governor) |
54 | return 0; | |
55 | ||
56 | cpuidle_uninstall_idle_handler(); | |
57 | ||
58 | if (cpuidle_curr_governor) { | |
59 | list_for_each_entry(dev, &cpuidle_detected_devices, device_list) | |
60 | cpuidle_disable_device(dev); | |
4f86d3a8 LB |
61 | } |
62 | ||
63 | cpuidle_curr_governor = gov; | |
64 | ||
65 | if (gov) { | |
4f86d3a8 LB |
66 | list_for_each_entry(dev, &cpuidle_detected_devices, device_list) |
67 | cpuidle_enable_device(dev); | |
68 | cpuidle_install_idle_handler(); | |
69 | printk(KERN_INFO "cpuidle: using governor %s\n", gov->name); | |
70 | } | |
71 | ||
72 | return 0; | |
73 | } | |
74 | ||
75 | /** | |
76 | * cpuidle_register_governor - registers a governor | |
77 | * @gov: the governor | |
78 | */ | |
79 | int cpuidle_register_governor(struct cpuidle_governor *gov) | |
80 | { | |
81 | int ret = -EEXIST; | |
82 | ||
83 | if (!gov || !gov->select) | |
84 | return -EINVAL; | |
85 | ||
62027aea LB |
86 | if (cpuidle_disabled()) |
87 | return -ENODEV; | |
88 | ||
4f86d3a8 LB |
89 | mutex_lock(&cpuidle_lock); |
90 | if (__cpuidle_find_governor(gov->name) == NULL) { | |
91 | ret = 0; | |
22782b3f | 92 | list_add_tail(&gov->governor_list, &cpuidle_governors); |
4f86d3a8 | 93 | if (!cpuidle_curr_governor || |
61cb5758 RW |
94 | !strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) || |
95 | (cpuidle_curr_governor->rating < gov->rating && | |
96 | strncasecmp(param_governor, cpuidle_curr_governor->name, | |
97 | CPUIDLE_NAME_LEN))) | |
4f86d3a8 LB |
98 | cpuidle_switch_governor(gov); |
99 | } | |
100 | mutex_unlock(&cpuidle_lock); | |
101 | ||
102 | return ret; | |
103 | } | |
0fc784fb RW |
104 | |
105 | /** | |
106 | * cpuidle_governor_latency_req - Compute a latency constraint for CPU | |
107 | * @cpu: Target CPU | |
108 | */ | |
109 | int cpuidle_governor_latency_req(unsigned int cpu) | |
110 | { | |
111 | int global_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); | |
112 | struct device *device = get_cpu_device(cpu); | |
8262331e | 113 | int device_req = dev_pm_qos_raw_resume_latency(device); |
0fc784fb RW |
114 | |
115 | return device_req < global_req ? device_req : global_req; | |
116 | } |