On Mon, Mar 09, 2015 at 09:16:36AM -0600, Lina Iyer wrote:
> From: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> [Minor clean ups and fixes of the per-cpu variable]
> ---
> drivers/cpuidle/cpuidle-arm.c | 34 +++++++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
> index 1c94b88..f7cdb73 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
> *
> @@ -93,6 +96,7 @@ static const struct of_device_id arm_idle_state_match[] __initconst = {
> static int __init arm_idle_init(void)
> {
> int cpu, ret;
> + struct cpuidle_device *dev;
> struct cpuidle_driver *drv = &arm_idle_driver;
>
> /*
> @@ -105,18 +109,46 @@ 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;
> }
> +
> + dev = kzalloc(sizeof(*dev), GFP_KERNEL);
devm_kzalloc? Otherwise, failures could lead to lost memory.
> + if (!dev)
> + return -ENOMEM;
> +
> + dev->cpu = cpu;
> + ret = cpuidle_register_device(dev);
> + if (ret) {
> + pr_err("Failed to register cpuidle device for CPU %d\n",
> + cpu);
> + return ret;
> + }
> +
> + per_cpu(cpuidle_arm_dev, cpu) = dev;
> }
>
> - return cpuidle_register(drv, NULL);
> + return 0;
> }
> device_initcall(arm_idle_init);
> --
> 2.1.0
>
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