[PATCH v3 1/7] cpuidle: Add common init interface and idle functionality
Rob Herring
robherring2 at gmail.com
Tue Jan 24 09:36:52 EST 2012
On 01/23/2012 10:37 PM, Robert Lee wrote:
> The patch adds some cpuidle initialization functionality commonly
> duplicated by many platforms.
>
> Signed-off-by: Robert Lee <rob.lee at linaro.org>
A few cosmetic comments below, but otherwise looks good.
Reviewed-by: Rob Herring <rob.herring at calxeda.com>
> ---
> drivers/cpuidle/Makefile | 2 +-
> drivers/cpuidle/common.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/cpuidle.h | 24 +++++++
> 3 files changed, 177 insertions(+), 1 deletions(-)
> create mode 100644 drivers/cpuidle/common.c
>
> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
> index 5634f88..2928d93 100644
> --- a/drivers/cpuidle/Makefile
> +++ b/drivers/cpuidle/Makefile
> @@ -2,4 +2,4 @@
> # Makefile for cpuidle.
> #
>
> -obj-y += cpuidle.o driver.o governor.o sysfs.o governors/
> +obj-y += cpuidle.o driver.o governor.o sysfs.o common.o governors/
> diff --git a/drivers/cpuidle/common.c b/drivers/cpuidle/common.c
> new file mode 100644
> index 0000000..dafa758
> --- /dev/null
> +++ b/drivers/cpuidle/common.c
> @@ -0,0 +1,152 @@
> +/*
> + * Copyright 2011 Freescale Semiconductor, Inc.
> + * Copyright 2011 Linaro Ltd.
2012 now...
> + *
> + * 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
> + */
> +
> +/*
> + * This code performs provides some commonly used cpuidle setup functionality
> + * used by many ARM SoC platforms. Providing this functionality here
> + * reduces the duplication of this code for each ARM platform that uses it.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/io.h>
> +#include <linux/cpuidle.h>
> +#include <linux/hrtimer.h>
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +#include <asm/proc-fns.h>
> +
> +static struct cpuidle_device __percpu * common_cpuidle_devices;
> +
> +static int (*do_idle[CPUIDLE_STATE_MAX])(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index);
> +
> +int cpuidle_def_idle(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index)
> +{
> + cpu_do_idle();
> + return index;
> +}
> +
> +static int simple_enter(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index)
> +{
> + ktime_t time_start, time_end;
> +
> + local_irq_disable();
> +
> + time_start = ktime_get();
> +
> + index = do_idle[index](dev, drv, index);
> +
> + time_end = ktime_get();
> +
> + local_irq_enable();
> +
> + dev->last_residency =
> + (int)ktime_to_us(ktime_sub(time_end, time_start));
> +
> + return index;
> +}
> +
> +void common_cpuidle_devices_uninit(void)
> +{
> + int cpu_id;
> + struct cpuidle_device *dev;
> +
> + for_each_possible_cpu(cpu_id) {
> + dev = per_cpu_ptr(common_cpuidle_devices, cpu_id);
> + cpuidle_unregister_device(dev);
> + }
> +
> + free_percpu(common_cpuidle_devices);
> +}
> +
> +/**
> + * common_cpuidle_init() - Provides some commonly used init functionality.
> + * @pdrv Pointer to your cpuidle_driver object.
> + * @simple Use the common simple_enter wrapper?
remove the ?
> + * @driver_data_init Pointer to your platform function to initialize your
> + * platform specific driver data. Use NULL if platform
> + * specific data is not needed.
> + *
> + * Common cpuidle init interface to provide common cpuidle functionality
> + * used by many platforms.
> + */
> +int __init common_cpuidle_init(struct cpuidle_driver *pdrv, bool simple,
> + void (*driver_data_init)(struct cpuidle_device *dev))
> +{
> + struct cpuidle_device *dev;
> + struct cpuidle_driver *drv;
> + int i, cpu_id, ret;
> +
> + if (!pdrv || pdrv->state_count > CPUIDLE_STATE_MAX) {
> + pr_err("%s: Invalid Input\n", __func__);
Using pr_fmt rather than function name is preferred.
> + return -EINVAL;
> + }
> +
> + drv = kmalloc(sizeof(struct cpuidle_driver), GFP_KERNEL);
> + if (!drv) {
> + pr_err("%s: no memory for cpuidle driver\n", __func__);
> + return -ENOMEM;
> + }
> +
> + *drv = *pdrv;
Perhaps a comment so it is clear you intend this to be struct copy.
> +
> + for (i = 0; simple && (i < drv->state_count); i++) {
> + do_idle[i] = drv->states[i].enter;
> + drv->states[i].enter = simple_enter;
> + }
> +
> + ret = cpuidle_register_driver(drv);
> + if (ret) {
> + pr_err("%s: Failed to register cpuidle driver\n", __func__);
> + goto free_drv;
> + }
> +
> + common_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> + if (common_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(common_cpuidle_devices, cpu_id);
> + dev->cpu = cpu_id;
> + dev->state_count = drv->state_count;
> +
> + if (driver_data_init)
> + driver_data_init(dev);
> +
> + ret = cpuidle_register_device(dev);
> + if (ret) {
> + pr_err("%s: Failed to register cpu %u\n",
> + __func__, cpu_id);
> + goto uninit;
> + }
> + }
> +
> + return 0;
> +uninit:
> +
> + common_cpuidle_devices_uninit();
> +
> +unregister_drv:
> +
> + cpuidle_unregister_driver(drv);
> +
> +free_drv:
> +
> + kfree(drv);
> +
> + return ret;
Remove all the blank lines in the error handling.
> +}
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 712abcc..2aa89db 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -56,6 +56,16 @@ struct cpuidle_state {
>
> #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
>
> +/* Common ARM WFI state */
> +#define CPUIDLE_ARM_WFI_STATE {\
> + .enter = cpuidle_def_idle,\
> + .exit_latency = 2,\
> + .target_residency = 1,\
> + .flags = CPUIDLE_FLAG_TIME_VALID,\
> + .name = "WFI",\
> + .desc = "ARM core clock gating (WFI)",\
> +}
> +
> /**
> * cpuidle_get_statedata - retrieves private driver state data
> * @st_usage: the state usage statistics
> @@ -141,6 +151,13 @@ extern void cpuidle_resume_and_unlock(void);
> extern int cpuidle_enable_device(struct cpuidle_device *dev);
> extern void cpuidle_disable_device(struct cpuidle_device *dev);
>
> +/* provide a default idle function */
> +extern int cpuidle_def_idle(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index);
> +extern int common_cpuidle_init(struct cpuidle_driver *drv, bool simple,
> + void (*driver_data_init)(struct cpuidle_device *dev));
> +extern void common_cpuidle_devices_uninit(void);
> +
> #else
> static inline void disable_cpuidle(void) { }
> static inline int cpuidle_idle_call(void) { return -ENODEV; }
> @@ -157,6 +174,13 @@ static inline void cpuidle_resume_and_unlock(void) { }
> static inline int cpuidle_enable_device(struct cpuidle_device *dev)
> {return -ENODEV; }
> static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
> +static inline int cpuidle_def_idle(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index)
> +{return -ENODEV; }
> +static inline int common_cpuidle_init(struct cpuidle_driver *pdrv,
> + bool simple, void (*driver_data_init)(struct cpuidle_device *dev))
> +{return -ENODEV; }
> +static inline void common_cpuidle_devices_uninit(void) { }
>
> #endif
>
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