2 * driver.c - driver support
4 * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
5 * Shaohua Li <shaohua.li@intel.com>
6 * Adam Belay <abelay@novell.com>
8 * This code is licenced under the GPL.
11 #include <linux/mutex.h>
12 #include <linux/module.h>
13 #include <linux/cpuidle.h>
17 DEFINE_SPINLOCK(cpuidle_driver_lock
);
19 static void __cpuidle_set_cpu_driver(struct cpuidle_driver
*drv
, int cpu
);
20 static struct cpuidle_driver
* __cpuidle_get_cpu_driver(int cpu
);
22 static void set_power_states(struct cpuidle_driver
*drv
)
27 * cpuidle driver should set the drv->power_specified bit
28 * before registering if the driver provides
29 * power_usage numbers.
31 * If power_specified is not set,
32 * we fill in power_usage with decreasing values as the
33 * cpuidle code has an implicit assumption that state Cn
34 * uses less power than C(n-1).
36 * With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned
37 * an power value of -1. So we use -2, -3, etc, for other
40 for (i
= CPUIDLE_DRIVER_STATE_START
; i
< drv
->state_count
; i
++)
41 drv
->states
[i
].power_usage
= -1 - i
;
44 static void __cpuidle_driver_init(struct cpuidle_driver
*drv
)
48 if (!drv
->power_specified
)
49 set_power_states(drv
);
52 static int __cpuidle_register_driver(struct cpuidle_driver
*drv
, int cpu
)
54 if (!drv
|| !drv
->state_count
)
57 if (cpuidle_disabled())
60 if (__cpuidle_get_cpu_driver(cpu
))
63 __cpuidle_driver_init(drv
);
65 __cpuidle_set_cpu_driver(drv
, cpu
);
70 static void __cpuidle_unregister_driver(struct cpuidle_driver
*drv
, int cpu
)
72 if (drv
!= __cpuidle_get_cpu_driver(cpu
))
75 if (!WARN_ON(drv
->refcnt
> 0))
76 __cpuidle_set_cpu_driver(NULL
, cpu
);
79 #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
81 static DEFINE_PER_CPU(struct cpuidle_driver
*, cpuidle_drivers
);
83 static void __cpuidle_set_cpu_driver(struct cpuidle_driver
*drv
, int cpu
)
85 per_cpu(cpuidle_drivers
, cpu
) = drv
;
88 static struct cpuidle_driver
*__cpuidle_get_cpu_driver(int cpu
)
90 return per_cpu(cpuidle_drivers
, cpu
);
93 static void __cpuidle_unregister_all_cpu_driver(struct cpuidle_driver
*drv
)
96 for_each_present_cpu(cpu
)
97 __cpuidle_unregister_driver(drv
, cpu
);
100 static int __cpuidle_register_all_cpu_driver(struct cpuidle_driver
*drv
)
105 for_each_present_cpu(cpu
) {
106 ret
= __cpuidle_register_driver(drv
, cpu
);
112 for_each_present_cpu(i
) {
115 __cpuidle_unregister_driver(drv
, i
);
122 int cpuidle_register_cpu_driver(struct cpuidle_driver
*drv
, int cpu
)
126 spin_lock(&cpuidle_driver_lock
);
127 ret
= __cpuidle_register_driver(drv
, cpu
);
128 spin_unlock(&cpuidle_driver_lock
);
133 void cpuidle_unregister_cpu_driver(struct cpuidle_driver
*drv
, int cpu
)
135 spin_lock(&cpuidle_driver_lock
);
136 __cpuidle_unregister_driver(drv
, cpu
);
137 spin_unlock(&cpuidle_driver_lock
);
141 * cpuidle_register_driver - registers a driver
144 int cpuidle_register_driver(struct cpuidle_driver
*drv
)
148 spin_lock(&cpuidle_driver_lock
);
149 ret
= __cpuidle_register_all_cpu_driver(drv
);
150 spin_unlock(&cpuidle_driver_lock
);
154 EXPORT_SYMBOL_GPL(cpuidle_register_driver
);
157 * cpuidle_unregister_driver - unregisters a driver
160 void cpuidle_unregister_driver(struct cpuidle_driver
*drv
)
162 spin_lock(&cpuidle_driver_lock
);
163 __cpuidle_unregister_all_cpu_driver(drv
);
164 spin_unlock(&cpuidle_driver_lock
);
166 EXPORT_SYMBOL_GPL(cpuidle_unregister_driver
);
170 static struct cpuidle_driver
*cpuidle_curr_driver
;
172 static inline void __cpuidle_set_cpu_driver(struct cpuidle_driver
*drv
, int cpu
)
174 cpuidle_curr_driver
= drv
;
177 static inline struct cpuidle_driver
*__cpuidle_get_cpu_driver(int cpu
)
179 return cpuidle_curr_driver
;
183 * cpuidle_register_driver - registers a driver
186 int cpuidle_register_driver(struct cpuidle_driver
*drv
)
191 spin_lock(&cpuidle_driver_lock
);
192 ret
= __cpuidle_register_driver(drv
, cpu
);
193 spin_unlock(&cpuidle_driver_lock
);
198 EXPORT_SYMBOL_GPL(cpuidle_register_driver
);
201 * cpuidle_unregister_driver - unregisters a driver
204 void cpuidle_unregister_driver(struct cpuidle_driver
*drv
)
209 spin_lock(&cpuidle_driver_lock
);
210 __cpuidle_unregister_driver(drv
, cpu
);
211 spin_unlock(&cpuidle_driver_lock
);
214 EXPORT_SYMBOL_GPL(cpuidle_unregister_driver
);
218 * cpuidle_get_driver - return the current driver
220 struct cpuidle_driver
*cpuidle_get_driver(void)
222 struct cpuidle_driver
*drv
;
226 drv
= __cpuidle_get_cpu_driver(cpu
);
231 EXPORT_SYMBOL_GPL(cpuidle_get_driver
);
234 * cpuidle_get_cpu_driver - return the driver tied with a cpu
236 struct cpuidle_driver
*cpuidle_get_cpu_driver(struct cpuidle_device
*dev
)
241 return __cpuidle_get_cpu_driver(dev
->cpu
);
243 EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver
);
245 struct cpuidle_driver
*cpuidle_driver_ref(void)
247 struct cpuidle_driver
*drv
;
249 spin_lock(&cpuidle_driver_lock
);
251 drv
= cpuidle_get_driver();
254 spin_unlock(&cpuidle_driver_lock
);
258 void cpuidle_driver_unref(void)
260 struct cpuidle_driver
*drv
= cpuidle_get_driver();
262 spin_lock(&cpuidle_driver_lock
);
264 if (drv
&& !WARN_ON(drv
->refcnt
<= 0))
267 spin_unlock(&cpuidle_driver_lock
);