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

Lorenzo Pieralisi
2015-03-19T11:08:03Z

On Wed, Mar 18, 2015 at 06:46:11PM +0000, 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.

http://www.spinics.net/lists/linux-acpi/msg55550.html

-ENXIO ?

>
> 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);
> +
> /*
> * 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 0;

>
> - return cpuidle_register(drv, NULL);
> +out_fail:
> + for (cpu--; cpu <= 0; cpu--) {

This loop is wrong.

> + dev = per_cpu(cpuidle_arm_dev, cpu);
> + cpuidle_unregister_device(dev);
> + kfree(dev);
> + }
> + cpuidle_unregister_driver(drv);
> + goto out;

You just:

return ret;

little point in jumping around to just return.

Lorenzo