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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 | /* * governor.c - governor support * * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> * Shaohua Li <shaohua.li@intel.com> * Adam Belay <abelay@novell.com> * * This code is licenced under the GPL. */ #include <linux/cpu.h> #include <linux/cpuidle.h> #include <linux/mutex.h> #include <linux/module.h> #include <linux/pm_qos.h> #include "cpuidle.h" char param_governor[CPUIDLE_NAME_LEN]; LIST_HEAD(cpuidle_governors); struct cpuidle_governor *cpuidle_curr_governor; struct cpuidle_governor *cpuidle_prev_governor; /** * cpuidle_find_governor - finds a governor of the specified name * @str: the name * * Must be called with cpuidle_lock acquired. */ struct cpuidle_governor *cpuidle_find_governor(const char *str) { struct cpuidle_governor *gov; list_for_each_entry(gov, &cpuidle_governors, governor_list) if (!strncasecmp(str, gov->name, CPUIDLE_NAME_LEN)) return gov; return NULL; } /** * cpuidle_switch_governor - changes the governor * @gov: the new target governor * Must be called with cpuidle_lock acquired. */ int cpuidle_switch_governor(struct cpuidle_governor *gov) { struct cpuidle_device *dev; if (!gov) return -EINVAL; if (gov == cpuidle_curr_governor) return 0; cpuidle_uninstall_idle_handler(); if (cpuidle_curr_governor) { list_for_each_entry(dev, &cpuidle_detected_devices, device_list) cpuidle_disable_device(dev); } cpuidle_curr_governor = gov; list_for_each_entry(dev, &cpuidle_detected_devices, device_list) cpuidle_enable_device(dev); cpuidle_install_idle_handler(); pr_info("cpuidle: using governor %s\n", gov->name); return 0; } /** * cpuidle_register_governor - registers a governor * @gov: the governor */ int cpuidle_register_governor(struct cpuidle_governor *gov) { int ret = -EEXIST; if (!gov || !gov->select) return -EINVAL; if (cpuidle_disabled()) return -ENODEV; mutex_lock(&cpuidle_lock); if (cpuidle_find_governor(gov->name) == NULL) { ret = 0; list_add_tail(&gov->governor_list, &cpuidle_governors); if (!cpuidle_curr_governor || !strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) || (cpuidle_curr_governor->rating < gov->rating && strncasecmp(param_governor, cpuidle_curr_governor->name, CPUIDLE_NAME_LEN))) cpuidle_switch_governor(gov); } mutex_unlock(&cpuidle_lock); return ret; } /** * cpuidle_governor_latency_req - Compute a latency constraint for CPU * @cpu: Target CPU */ s64 cpuidle_governor_latency_req(unsigned int cpu) { struct device *device = get_cpu_device(cpu); int device_req = dev_pm_qos_raw_resume_latency(device); int global_req = cpu_latency_qos_limit(); if (device_req > global_req) device_req = global_req; return (s64)device_req * NSEC_PER_USEC; } |