From bf4d1b5ddb78f86078ac6ae0415802d5f0c68f92 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Wed, 31 Oct 2012 16:44:48 +0000 Subject: cpuidle: support multiple drivers With the tegra3 and the big.LITTLE [1] new architectures, several cpus with different characteristics (latencies and states) can co-exists on the system. The cpuidle framework has the limitation of handling only identical cpus. This patch removes this limitation by introducing the multiple driver support for cpuidle. This option is configurable at compile time and should be enabled for the architectures mentioned above. So there is no impact for the other platforms if the option is disabled. The option defaults to 'n'. Note the multiple drivers support is also compatible with the existing drivers, even if just one driver is needed, all the cpu will be tied to this driver using an extra small chunk of processor memory. The multiple driver support use a per-cpu driver pointer instead of a global variable and the accessor to this variable are done from a cpu context. In order to keep the compatibility with the existing drivers, the function 'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register the specified driver for all the cpus. The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver remains the same except the driver name will be related to the current cpu. The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added allowing to read the per cpu driver name. [1] http://lwn.net/Articles/481055/ Signed-off-by: Daniel Lezcano Acked-by: Peter De Schrijver Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/cpuidle.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/cpuidle/cpuidle.h') diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h index f6b0923c2253..ee97e9672ecf 100644 --- a/drivers/cpuidle/cpuidle.h +++ b/drivers/cpuidle/cpuidle.h @@ -28,8 +28,8 @@ struct device; extern int cpuidle_add_interface(struct device *dev); extern void cpuidle_remove_interface(struct device *dev); -extern int cpuidle_add_state_sysfs(struct cpuidle_device *device); -extern void cpuidle_remove_state_sysfs(struct cpuidle_device *device); +extern int cpuidle_add_device_sysfs(struct cpuidle_device *device); +extern void cpuidle_remove_device_sysfs(struct cpuidle_device *device); extern int cpuidle_add_sysfs(struct cpuidle_device *dev); extern void cpuidle_remove_sysfs(struct cpuidle_device *dev); -- cgit v1.2.3