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authorDaniel Lezcano <daniel.lezcano@linaro.org>2013-04-23 08:54:33 +0000
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-04-23 13:45:22 +0200
commit4c637b2175a0dc65d533494225525c6c82d73293 (patch)
tree89df00e95c52557139a1f9c151344b3c04681c7f /drivers/cpuidle/cpuidle.c
parent80b1c1999edbba3a411335f1650f0d92da391516 (diff)
downloadlinux-linaro-stable-4c637b2175a0dc65d533494225525c6c82d73293.tar.gz
cpuidle: make a single register function for all
The usual scheme to initialize a cpuidle driver on a SMP is: cpuidle_register_driver(drv); for_each_possible_cpu(cpu) { device = &per_cpu(cpuidle_dev, cpu); cpuidle_register_device(device); } This code is duplicated in each cpuidle driver. On UP systems, it is done this way: cpuidle_register_driver(drv); device = &per_cpu(cpuidle_dev, cpu); cpuidle_register_device(device); On UP, the macro 'for_each_cpu' does one iteration: #define for_each_cpu(cpu, mask) \ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) Hence, the initialization loop is the same for UP than SMP. Beside, we saw different bugs / mis-initialization / return code unchecked in the different drivers, the code is duplicated including bugs. After fixing all these ones, it appears the initialization pattern is the same for everyone. Please note, some drivers are doing dev->state_count = drv->state_count. This is not necessary because it is done by the cpuidle_enable_device function in the cpuidle framework. This is true, until you have the same states for all your devices. Otherwise, the 'low level' API should be used instead with the specific initialization for the driver. Let's add a wrapper function doing this initialization with a cpumask parameter for the coupled idle states and use it for all the drivers. That will save a lot of LOC, consolidate the code, and the modifications in the future could be done in a single place. Another benefit is the consolidation of the cpuidle_device variable which is now in the cpuidle framework and no longer spread accross the different arch specific drivers. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle.c')
-rw-r--r--drivers/cpuidle/cpuidle.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 0da795b9dbbf..49e8d302af55 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -24,6 +24,7 @@
#include "cpuidle.h"
DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
DEFINE_MUTEX(cpuidle_lock);
LIST_HEAD(cpuidle_detected_devices);
@@ -453,6 +454,77 @@ void cpuidle_unregister_device(struct cpuidle_device *dev)
EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
+/*
+ * cpuidle_unregister: unregister a driver and the devices. This function
+ * can be used only if the driver has been previously registered through
+ * the cpuidle_register function.
+ *
+ * @drv: a valid pointer to a struct cpuidle_driver
+ */
+void cpuidle_unregister(struct cpuidle_driver *drv)
+{
+ int cpu;
+ struct cpuidle_device *device;
+
+ for_each_possible_cpu(cpu) {
+ device = &per_cpu(cpuidle_dev, cpu);
+ cpuidle_unregister_device(device);
+ }
+
+ cpuidle_unregister_driver(drv);
+}
+EXPORT_SYMBOL_GPL(cpuidle_unregister);
+
+/**
+ * cpuidle_register: registers the driver and the cpu devices with the
+ * coupled_cpus passed as parameter. This function is used for all common
+ * initialization pattern there are in the arch specific drivers. The
+ * devices is globally defined in this file.
+ *
+ * @drv : a valid pointer to a struct cpuidle_driver
+ * @coupled_cpus: a cpumask for the coupled states
+ *
+ * Returns 0 on success, < 0 otherwise
+ */
+int cpuidle_register(struct cpuidle_driver *drv,
+ const struct cpumask *const coupled_cpus)
+{
+ int ret, cpu;
+ struct cpuidle_device *device;
+
+ ret = cpuidle_register_driver(drv);
+ if (ret) {
+ pr_err("failed to register cpuidle driver\n");
+ return ret;
+ }
+
+ for_each_possible_cpu(cpu) {
+ device = &per_cpu(cpuidle_dev, cpu);
+ device->cpu = cpu;
+
+#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
+ /*
+ * On multiplatform for ARM, the coupled idle states could
+ * enabled in the kernel even if the cpuidle driver does not
+ * use it. Note, coupled_cpus is a struct copy.
+ */
+ if (coupled_cpus)
+ device->coupled_cpus = *coupled_cpus;
+#endif
+ ret = cpuidle_register_device(device);
+ if (!ret)
+ continue;
+
+ pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
+
+ cpuidle_unregister(drv);
+ break;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpuidle_register);
+
#ifdef CONFIG_SMP
static void smp_callback(void *v)