Re: [PATCH V2 7/8] ARM: cpuidle: Register per cpuidle device

Lina Iyer
2015-03-19T15:31:12Z

On Wed, Mar 18 2015 at 12:46 -0600, Daniel Lezcano wrote:
>Some architectures have some cpus which does not support idle states.
>
>Let the underlying low level code to return -ENOSYS when it is not
>possible to set an idle state.
>
>Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>---
> drivers/cpuidle/cpuidle-arm.c | 45 +++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 43 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
>index 1c94b88..0682ed0 100644
>--- a/drivers/cpuidle/cpuidle-arm.c
>+++ b/drivers/cpuidle/cpuidle-arm.c
>@@ -17,11 +17,14 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/of.h>
>+#include <linux/slab.h>
>
> #include <asm/cpuidle.h>
>
> #include "dt_idle_states.h"
>
>+static DEFINE_PER_CPU(struct cpuidle_device, *cpuidle_arm_dev);

Is a per-cpu variable needed? There seems to be no per-cpu access, other
than at init.

>+
> /*
> * arm_enter_idle_state - Programs CPU to enter the specified state
> *
>@@ -94,6 +97,7 @@ static int __init arm_idle_init(void)
> {
> int cpu, ret;
> struct cpuidle_driver *drv = &arm_idle_driver;
>+ struct cpuidle_device *dev;
>
> /*
> * Initialize idle states data, starting at index 1.
>@@ -105,18 +109,55 @@ static int __init arm_idle_init(void)
> if (ret <= 0)
> return ret ? : -ENODEV;
>
>+ ret = cpuidle_register_driver(drv);
>+ if (ret) {
>+ pr_err("Failed to register cpuidle driver\n");
>+ return ret;
>+ }
>+
> /*
> * Call arch CPU operations in order to initialize
> * idle states suspend back-end specific data
> */
> for_each_possible_cpu(cpu) {
> ret = arm_cpuidle_init(cpu);
>+
>+ /* This cpu does not support any idle states */
>+ if (ret == -ENOSYS)
>+ continue;
>+
> if (ret) {
> pr_err("CPU %d failed to init idle CPU ops\n", cpu);
>- return ret;
>+ goto out_fail;
>+ }
>+
>+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
>+ if (!dev) {
>+ pr_err("Failed to allocate cpuidle device\n");
>+ goto out_fail;
>+ }
>+
>+ dev->cpu = cpu;
>+ per_cpu(cpuidle_arm_dev, cpu) = dev;
>+
>+ ret = cpuidle_register_device(dev);
>+ if (ret) {
>+ pr_err("Failed to register cpuidle device for CPU %d\n",
>+ cpu);
>+ kfree(dev);
>+ goto out_fail;
> }
> }
>+out:
>+ return ret;
>
>- return cpuidle_register(drv, NULL);
>+out_fail:
>+ for (cpu--; cpu <= 0; cpu--) {
>+ dev = per_cpu(cpuidle_arm_dev, cpu);
>+ cpuidle_unregister_device(dev);
>+ kfree(dev);
>+ }
>+ cpuidle_unregister_driver(drv);
>+ goto out;
> }
> device_initcall(arm_idle_init);
>--
>1.9.1
>