Re: [PATCH v2 1/3] ARM: imx: Add common imx cpuidle initfunctionality.

From: Shawn Guo
Date: Tue May 01 2012 - 23:13:20 EST


On Tue, May 01, 2012 at 09:12:38PM -0500, Robert Lee wrote:
> Add common cpuidle init functionality that can be used by various
> imx platforms.
>
> Signed-off-by: Robert Lee <rob.lee@xxxxxxxxxx>
> ---
> arch/arm/plat-mxc/Makefile | 1 +
> arch/arm/plat-mxc/cpuidle.c | 80 ++++++++++++++++++++++++++++++
> arch/arm/plat-mxc/include/mach/cpuidle.h | 22 ++++++++
> 3 files changed, 103 insertions(+)
> create mode 100644 arch/arm/plat-mxc/cpuidle.c
> create mode 100644 arch/arm/plat-mxc/include/mach/cpuidle.h
>
> diff --git a/arch/arm/plat-mxc/Makefile b/arch/arm/plat-mxc/Makefile
> index e81290c..63b064b 100644
> --- a/arch/arm/plat-mxc/Makefile
> +++ b/arch/arm/plat-mxc/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_MXC_ULPI) += ulpi.o
> obj-$(CONFIG_MXC_USE_EPIT) += epit.o
> obj-$(CONFIG_MXC_DEBUG_BOARD) += 3ds_debugboard.o
> obj-$(CONFIG_CPU_FREQ_IMX) += cpufreq.o
> +obj-$(CONFIG_CPU_IDLE) += cpuidle.o
> ifdef CONFIG_SND_IMX_SOC
> obj-y += ssi-fiq.o
> obj-y += ssi-fiq-ksym.o
> diff --git a/arch/arm/plat-mxc/cpuidle.c b/arch/arm/plat-mxc/cpuidle.c
> new file mode 100644
> index 0000000..b7a5e1c
> --- /dev/null
> +++ b/arch/arm/plat-mxc/cpuidle.c
> @@ -0,0 +1,80 @@
> +/*
> + * Copyright 2012 Freescale Semiconductor, Inc.
> + * Copyright 2012 Linaro Ltd.
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/io.h>
> +#include <linux/cpuidle.h>
> +#include <linux/hrtimer.h>
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +
> +static struct cpuidle_device __percpu * imx_cpuidle_devices;
> +
> +void imx_cpuidle_devices_uninit(void)
> +{
> + int cpu_id;
> + struct cpuidle_device *dev;
> +
> + for_each_possible_cpu(cpu_id) {
> + dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
> + cpuidle_unregister_device(dev);
> + }
> +
> + free_percpu(imx_cpuidle_devices);
> +}

Does this function need to be exported? I haven't seen it being
used anywhere outside this file. Also, can it be __init?

> +
> +int __init imx_cpuidle_init(struct cpuidle_driver *drv)
> +{
> + struct cpuidle_device *dev;
> + int cpu_id, ret;
> +
> + if (!drv || drv->state_count > CPUIDLE_STATE_MAX) {
> + pr_err("%s: Invalid Input\n", __func__);
> + return -EINVAL;
> + }
> +
> + ret = cpuidle_register_driver(drv);
> + if (ret) {
> + pr_err("%s: Failed to register cpuidle driver with error: %d\n",
> + __func__, ret);
> + return ret;
> + }
> +
> + imx_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> + if (imx_cpuidle_devices == NULL) {
> + ret = -ENOMEM;
> + goto unregister_drv;
> + }
> +
> + /* initialize state data for each cpuidle_device */
> + for_each_possible_cpu(cpu_id) {
> + dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
> + dev->cpu = cpu_id;
> + dev->state_count = drv->state_count;
> +
> + ret = cpuidle_register_device(dev);
> + if (ret) {
> + pr_err("%s: Failed to register cpu %u\n",
> + __func__, cpu_id);

Nit: print ret (error code) too?

> + goto uninit;
> + }
> + }
> +
> + return 0;
> +
> +uninit:
> + imx_cpuidle_devices_uninit();
> +
> +unregister_drv:
> + cpuidle_unregister_driver(drv);
> + return ret;
> +}
> diff --git a/arch/arm/plat-mxc/include/mach/cpuidle.h b/arch/arm/plat-mxc/include/mach/cpuidle.h
> new file mode 100644
> index 0000000..8612510
> --- /dev/null
> +++ b/arch/arm/plat-mxc/include/mach/cpuidle.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright 2012 Freescale Semiconductor, Inc.
> + * Copyright 2012 Linaro Ltd.
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +
> +#include <linux/cpuidle.h>
> +
> +#ifdef CONFIG_CPU_IDLE
> +extern void imx_cpuidle_devices_uninit(void);
> +extern int imx_cpuidle_init(struct cpuidle_driver *drv);
> +#else
> +static inline void imx_cpuidle_devices_uninit(void) {}
> +static inline int imx_cpuidle_init(struct cpuidle_driver *drv)
> +{ return -ENODEV; }

Nit: if it can not be in the same line with function name, we usually
have it be:

{
return -ENODEV;
}

> +#endif
> --
> 1.7.10
>

--
Regards,
Shawn
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