[RFC PATCH v15 01/11] ARM: cpuidle: Register per cpuidle device

[Andy Gross]

On Mon, Mar 09, 2015 at 09:16:36AM -0600, Lina Iyer wrote:
> From: Daniel Lezcano <daniel.lezcano at linaro.org>
> 
> 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 at linaro.org>
> Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
> [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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