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120 lines
2.7 KiB
120 lines
2.7 KiB
/* |
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* governor.c - governor support |
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* |
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* (C) 2006-2007 Venkatesh Pallipadi <[email protected]> |
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* Shaohua Li <[email protected]> |
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* Adam Belay <[email protected]> |
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* |
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* This code is licenced under the GPL. |
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*/ |
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#include <linux/cpu.h> |
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#include <linux/cpuidle.h> |
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#include <linux/mutex.h> |
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#include <linux/module.h> |
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#include <linux/pm_qos.h> |
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#include "cpuidle.h" |
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char param_governor[CPUIDLE_NAME_LEN]; |
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LIST_HEAD(cpuidle_governors); |
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struct cpuidle_governor *cpuidle_curr_governor; |
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struct cpuidle_governor *cpuidle_prev_governor; |
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/** |
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* cpuidle_find_governor - finds a governor of the specified name |
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* @str: the name |
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* |
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* Must be called with cpuidle_lock acquired. |
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*/ |
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struct cpuidle_governor *cpuidle_find_governor(const char *str) |
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{ |
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struct cpuidle_governor *gov; |
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list_for_each_entry(gov, &cpuidle_governors, governor_list) |
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if (!strncasecmp(str, gov->name, CPUIDLE_NAME_LEN)) |
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return gov; |
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return NULL; |
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} |
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/** |
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* cpuidle_switch_governor - changes the governor |
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* @gov: the new target governor |
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* Must be called with cpuidle_lock acquired. |
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*/ |
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int cpuidle_switch_governor(struct cpuidle_governor *gov) |
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{ |
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struct cpuidle_device *dev; |
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if (!gov) |
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return -EINVAL; |
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if (gov == cpuidle_curr_governor) |
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return 0; |
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cpuidle_uninstall_idle_handler(); |
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if (cpuidle_curr_governor) { |
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list_for_each_entry(dev, &cpuidle_detected_devices, device_list) |
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cpuidle_disable_device(dev); |
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} |
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cpuidle_curr_governor = gov; |
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if (gov) { |
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list_for_each_entry(dev, &cpuidle_detected_devices, device_list) |
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cpuidle_enable_device(dev); |
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cpuidle_install_idle_handler(); |
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printk(KERN_INFO "cpuidle: using governor %s\n", gov->name); |
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} |
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return 0; |
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} |
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/** |
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* cpuidle_register_governor - registers a governor |
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* @gov: the governor |
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*/ |
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int cpuidle_register_governor(struct cpuidle_governor *gov) |
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{ |
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int ret = -EEXIST; |
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if (!gov || !gov->select) |
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return -EINVAL; |
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if (cpuidle_disabled()) |
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return -ENODEV; |
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mutex_lock(&cpuidle_lock); |
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if (cpuidle_find_governor(gov->name) == NULL) { |
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ret = 0; |
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list_add_tail(&gov->governor_list, &cpuidle_governors); |
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if (!cpuidle_curr_governor || |
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!strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) || |
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(cpuidle_curr_governor->rating < gov->rating && |
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strncasecmp(param_governor, cpuidle_curr_governor->name, |
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CPUIDLE_NAME_LEN))) |
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cpuidle_switch_governor(gov); |
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} |
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mutex_unlock(&cpuidle_lock); |
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return ret; |
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} |
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/** |
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* cpuidle_governor_latency_req - Compute a latency constraint for CPU |
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* @cpu: Target CPU |
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*/ |
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s64 cpuidle_governor_latency_req(unsigned int cpu) |
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{ |
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struct device *device = get_cpu_device(cpu); |
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int device_req = dev_pm_qos_raw_resume_latency(device); |
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int global_req = cpu_latency_qos_limit(); |
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if (device_req > global_req) |
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device_req = global_req; |
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return (s64)device_req * NSEC_PER_USEC; |
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}
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