[PATCH] ARM: EXYNOS4: CPUIDLE Support

[Kukjin Kim]

Kyungmin Park wrote:
> 
> On Tue, Mar 15, 2011 at 10:57 PM, Kukjin Kim <kgene.kim at samsung.com>
wrote:
> > Jaecheol Lee wrote:
> >>
> >> This patch supports cpuidle framework for EXYNOS4210. Currently,
> >> Only one idle state is possible to use, but more idle states can
> >> be added following by this patch.
> >>
> >> Signed-off-by: Jaecheol Lee <jc.lee at samsung.com>
> >> ---
> >>  arch/arm/mach-exynos4/Makefile  |    1 +
> >>  arch/arm/mach-exynos4/cpuidle.c |   87
> >> +++++++++++++++++++++++++++++++++++++++
> >>  2 files changed, 88 insertions(+), 0 deletions(-)
> >>  create mode 100644 arch/arm/mach-exynos4/cpuidle.c
> >>
> >> diff --git a/arch/arm/mach-exynos4/Makefile b/arch/arm/mach-
> > exynos4/Makefile
> >> index 461ae57..bf206fa 100644
> >> --- a/arch/arm/mach-exynos4/Makefile
> >> +++ b/arch/arm/mach-exynos4/Makefile
> >> @@ -16,6 +16,7 @@ obj-$(CONFIG_CPU_EXYNOS4210)        += cpu.o init.o
> > clock.o
> >> irq-combiner.o
> >>  obj-$(CONFIG_CPU_EXYNOS4210) += cpu.o init.o clock.o irq-combiner.o
> >>  obj-$(CONFIG_CPU_EXYNOS4210) += setup-i2c0.o time.o gpiolib.o
irq-eint.o
> >> dma.o
> >>  obj-$(CONFIG_CPU_FREQ)               += cpufreq.o
> >> +obj-$(CONFIG_CPU_IDLE)               += cpuidle.o
> >>
> >>  obj-$(CONFIG_SMP)            += platsmp.o headsmp.o
> >>  obj-$(CONFIG_LOCAL_TIMERS)   += localtimer.o
> >> diff --git a/arch/arm/mach-exynos4/cpuidle.c b/arch/arm/mach-
> >> exynos4/cpuidle.c
> >> new file mode 100644
> >> index 0000000..a543a18
> >> --- /dev/null
> >> +++ b/arch/arm/mach-exynos4/cpuidle.c
> >> @@ -0,0 +1,87 @@
> >> +/* linux/arch/arm/mach-exynos4/cpuidle.c
> >> + *
> >> + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> >> + *           http://www.samsung.com
> >> + *
> >> + * This program is free software; you can redistribute it and/or
modify
> >> + * it under the terms of the GNU General Public License version 2 as
> >> + * published by the Free Software Foundation.
> >> +*/
> >> +
> >> +#include <linux/kernel.h>
> >> +#include <linux/init.h>
> >> +#include <linux/cpuidle.h>
> >> +#include <linux/io.h>
> >> +
> >> +#include <asm/proc-fns.h>
> >> +
> >> +static int exynos4_enter_idle(struct cpuidle_device *dev,
> >> +                           struct cpuidle_state *state);
> >> +
> >> +static struct cpuidle_state exynos4_cpuidle_set[] = {
> >> +     [0] = {
> >> +             .enter                  = exynos4_enter_idle,
> >> +             .exit_latency           = 1,
> >> +             .target_residency       = 100000,
> >> +             .flags                  = CPUIDLE_FLAG_TIME_VALID,
> >> +             .name                   = "IDLE",
> >> +             .desc                   = "ARM clock gating(WFI)",
> >> +     },
> >> +};
> >> +
> >> +static DEFINE_PER_CPU(struct cpuidle_device, exynos4_cpuidle_device);
> >> +
> >> +static struct cpuidle_driver exynos4_idle_driver = {
> >> +     .name           = "exynos4_idle",
> >> +     .owner          = THIS_MODULE,
> >> +};
> >> +
> >> +static int exynos4_enter_idle(struct cpuidle_device *dev,
> >> +                           struct cpuidle_state *state)
> >> +{
> >> +     struct timeval before, after;
> >> +     int idle_time;
> >> +
> >> +     local_irq_disable();
> >> +     do_gettimeofday(&before);
> >> +
> >> +     cpu_do_idle();
> >> +
> >> +     do_gettimeofday(&after);
> >> +     local_irq_enable();
> >> +     idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
> >> +                 (after.tv_usec - before.tv_usec);
> >> +
> >> +     return idle_time;
> >> +}
> >> +
> >> +static int __init exynos4_init_cpuidle(void)
> >> +{
> >> +     int i, max_cpuidle_state, cpu_id;
> >> +     struct cpuidle_device *device;
> >> +
> >> +     cpuidle_register_driver(&exynos4_idle_driver);
> >> +
> >> +     for_each_cpu(cpu_id, cpu_online_mask) {
> >> +             device = &per_cpu(exynos4_cpuidle_device, cpu_id);
> >> +             device->cpu = cpu_id;
> >> +
> >> +             device->state_count = (sizeof(exynos4_cpuidle_set) /
> >> +                                            sizeof(struct
> > cpuidle_state));
> >> +
> >> +             max_cpuidle_state = device->state_count;
> >> +
> >> +             for (i = 0; i < max_cpuidle_state; i++) {
> >> +                     memcpy(&device->states[i],
&exynos4_cpuidle_set[i],
> >> +                                     sizeof(struct cpuidle_state));
> >> +             }
> >> +
> >> +             if (cpuidle_register_device(device)) {
> >> +                     printk(KERN_ERR "CPUidle register device
> > failed\n,");
> >> +                     return -EIO;
> >> +             }
> >> +     }
> >> +     return 0;
> >> +}
> >> +
> >> +device_initcall(exynos4_init_cpuidle);
> >> --
> >> 1.7.1
> >
> > Cc'ed Kyungmin Park.
> >
> > Hmm...I'm thinking that we need more discussion on this CPUIDLE later,
> > about method, IDLE states and so on.
> 
> It's not good decision. As cpufreq, support the basic cpuidle at
> mainline kernel, and add it more states at later.
> Except the state name "IDLE", I hope it will be changed to "C1" for
> support cpuidle tool.
> 
> Mr. Lee will support the C states soon.
> 
> I'm okay with Mr. Lee patch.

Yeah, if required, we can update it later.

Ok, his code looks ok to me.
Will apply.

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.