On Tue, 15 Apr 2014 18:38:39 +0200 Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote: > > On 04/15/2014 05:54 PM, Lukasz Majewski wrote: > > Hi Daniel, > > > >> On 04/15/2014 08:37 AM, Lukasz Majewski wrote: > >>> Hi Daniel, > >>> > >>>> The following driver is for exynos4210. I did not yet finished > >>>> the other boards, so I created a specific driver for 4210 which > >>>> could be merged later. > >>>> > >>> > >>> If I may ask - do you plan to develop this code for Exynos4412 in > >>> a near future? > >> > >> Yes it is in my plan. > >> > >>> I did some tests (with hotplug) and it turns out, that due to > >>> static leakage current one can save up to 12 % of power > >>> consumption when power domains for cores are disabled. > >>> > >>> > >>> Such notable power consumption reduction could drive (and justify) > >>> the further development of power aware scheduling code. > >>> > >>> If you don't have time, then I can offer myself to develop the > >>> code. I just want to avoid potential duplication of effort. > >> > >> I would be very glad if we can cooperate. Thanks for proposing your > >> help. > > > > You are welcome :-) > > > >> > >> I have put a branch containing the cleanups + driver moving + dual > >> cpu support, so you can base your work in it. > >> > >> git://git.linaro.org/people/daniel.lezcano/linux.git > >> cpuidle/samsung-next > > > > Thanks for sharing code. I will look into it. > > > >> > >> I am wondering if the 5250 board wouldn't make sense as a primary > >> target before the 4412... > > > > I'm working on a device based on 4412, not 5250. Therefore, I would > > prefer to have this concept implemented on 4412 as soon as possible > > to not hinder my scheduler related experiments. > > > > If you have other priorities, then we can split the work. What do > > you think? > > It is ok for me if you want to handle the cpuidle driver 4412. Ok. Thanks :-) > Will > you create a new driver or extend this dual cpu driver to support 4 > cpus ? For the beginning, I will try to extend the solution proposed for Exynos4210. However, because of the Easter break, the code will be delivered at next week. > > > >>>> The driver is based on Colin Cross's driver found at: > >>>> > >>>> https://android.googlesource.com/kernel/exynos/+/e686b1ec67423c40b4fdf811f9a4dfa3b393a010%5E%5E!/ > >>>> > >>>> This one was based on a 3.4 kernel and an old API. > >>>> > >>>> It has been refreshed, simplified and based on the recent code > >>>> cleanup I sent today. > >>>> > >>>> The AFTR could be entered when all the cpus (except cpu0) are > >>>> down. In order to reach this situation, the couple idle states > >>>> are used. > >>>> > >>>> There is a sync barrier at the entry and the exit of the low > >>>> power function. So all cpus will enter and exit the function at > >>>> the same time. > >>>> > >>>> At this point, CPU0 knows the other cpu will power down itself. > >>>> CPU0 waits for the CPU1 to be powered down and then initiate the > >>>> AFTR power down sequence. > >>>> > >>>> No interrupts are handled by CPU1, this is why we switch to the > >>>> timer broadcast even if the local timer is not impacted by the > >>>> idle state. > >>>> > >>>> When CPU0 wakes up, it powers up CPU1 and waits for it to boot. > >>>> Then they both exit the idle function. > >>>> > >>>> This driver allows the exynos4210 to have the same power > >>>> consumption at idle time than the one when we have to unplug CPU1 > >>>> in order to let CPU0 to reach the AFTR state. > >>>> > >>>> This patch is a RFC because, we have to find a way to remove the > >>>> macros definitions and cpu powerdown function without pulling the > >>>> arch dependent headers. > >>>> > >>>> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > >>>> --- > >>>> arch/arm/mach-exynos/common.c | 11 +- > >>>> drivers/cpuidle/Kconfig.arm | 8 ++ > >>>> drivers/cpuidle/Makefile | 1 + > >>>> drivers/cpuidle/cpuidle-exynos4210.c | 226 > >>>> ++++++++++++++++++++++++++++++++++ 4 files changed, 245 > >>>> insertions(+), 1 deletion(-) create mode 100644 > >>>> drivers/cpuidle/cpuidle-exynos4210.c > >>>> > >>>> diff --git a/arch/arm/mach-exynos/common.c > >>>> b/arch/arm/mach-exynos/common.c index d5fa21e..1765a98 100644 > >>>> --- a/arch/arm/mach-exynos/common.c > >>>> +++ b/arch/arm/mach-exynos/common.c > >>>> @@ -299,9 +299,18 @@ static struct platform_device exynos_cpuidle > >>>> = { .id = -1, > >>>> }; > >>>> > >>>> +static struct platform_device exynos4210_cpuidle = { > >>>> + .name = "exynos4210-cpuidle", > >>>> + .dev.platform_data = exynos_sys_powerdown_aftr, > >>>> + .id = -1, > >>>> +}; > >>>> + > >>>> void __init exynos_cpuidle_init(void) > >>>> { > >>>> - platform_device_register(&exynos_cpuidle); > >>>> + if (soc_is_exynos4210()) > >>>> + platform_device_register(&exynos4210_cpuidle); > >>>> + else > >>>> + platform_device_register(&exynos_cpuidle); > >>>> } > >>>> > >>>> void __init exynos_cpufreq_init(void) > >>>> diff --git a/drivers/cpuidle/Kconfig.arm > >>>> b/drivers/cpuidle/Kconfig.arm index 92f0c12..2772130 100644 > >>>> --- a/drivers/cpuidle/Kconfig.arm > >>>> +++ b/drivers/cpuidle/Kconfig.arm > >>>> @@ -51,3 +51,11 @@ config ARM_EXYNOS_CPUIDLE > >>>> depends on ARCH_EXYNOS > >>>> help > >>>> Select this to enable cpuidle for Exynos processors > >>>> + > >>>> +config ARM_EXYNOS4210_CPUIDLE > >>>> + bool "Cpu Idle Driver for the Exynos 4210 processor" > >>>> + default y > >>>> + depends on ARCH_EXYNOS > >>>> + select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP > >>>> + help > >>>> + Select this to enable cpuidle for the Exynos 4210 > >>>> processors diff --git a/drivers/cpuidle/Makefile > >>>> b/drivers/cpuidle/Makefile index 0d1540a..e0ec9bc 100644 > >>>> --- a/drivers/cpuidle/Makefile > >>>> +++ b/drivers/cpuidle/Makefile > >>>> @@ -14,6 +14,7 @@ obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) > >>>> += cpuidle-zynq.o obj-$(CONFIG_ARM_U8500_CPUIDLE) += > >>>> cpuidle-ux500.o obj-$(CONFIG_ARM_AT91_CPUIDLE) += > >>>> cpuidle-at91.o obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += > >>>> cpuidle-exynos.o +obj-$(CONFIG_ARM_EXYNOS4210_CPUIDLE) += > >>>> cpuidle-exynos4210.o > >>>> > >>>> ############################################################################### > >>>> # POWERPC drivers > >>>> diff --git a/drivers/cpuidle/cpuidle-exynos4210.c > >>>> b/drivers/cpuidle/cpuidle-exynos4210.c new file mode 100644 > >>>> index 0000000..56f6d51 > >>>> --- /dev/null > >>>> +++ b/drivers/cpuidle/cpuidle-exynos4210.c > >>>> @@ -0,0 +1,226 @@ > >>>> +/* > >>>> + * Copyright (c) 2014 Samsung Electronics Co., Ltd. > >>>> + * http://www.samsung.com > >>>> + * > >>>> + * Copyright (c) 2014 Linaro : Daniel Lezcano > >>>> <daniel.lezcano@xxxxxxxxxx> > >>>> + * http://www.linaro.org > >>>> + * > >>>> + * Based on the work of Colin Cross <ccross@xxxxxxxxxxx> > >>>> + * > >>>> + * 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/cpuidle.h> > >>>> +#include <linux/cpu_pm.h> > >>>> +#include <linux/io.h> > >>>> +#include <linux/platform_device.h> > >>>> + > >>>> +#include <asm/proc-fns.h> > >>>> +#include <asm/suspend.h> > >>>> +#include <asm/cpuidle.h> > >>>> + > >>>> +#include <plat/pm.h> > >>>> +#include <plat/cpu.h> > >>>> +#include <plat/map-base.h> > >>>> +#include <plat/map-s5p.h> > >>>> + > >>>> +static atomic_t exynos_idle_barrier; > >>>> +static atomic_t cpu1_wakeup = ATOMIC_INIT(0); > >>>> + > >>>> +#define BOOT_VECTOR S5P_VA_SYSRAM > >>>> +#define S5P_VA_PMU S3C_ADDR(0x02180000) > >>>> +#define S5P_PMUREG(x) (S5P_VA_PMU + (x)) > >>>> +#define S5P_ARM_CORE1_CONFIGURATION S5P_PMUREG(0x2080) > >>>> +#define S5P_ARM_CORE1_STATUS S5P_PMUREG(0x2084) > >>>> + > >>>> +static void (*exynos_aftr)(void); > >>>> + > >>>> +static int cpu_suspend_finish(unsigned long flags) > >>>> +{ > >>>> + if (flags) > >>>> + exynos_aftr(); > >>>> + > >>>> + cpu_do_idle(); > >>>> + > >>>> + return -1; > >>>> +} > >>>> + > >>>> +static int exynos_cpu0_enter_aftr(void) > >>>> +{ > >>>> + int ret = -1; > >>>> + > >>>> + /* > >>>> + * If the other cpu is powered on, we have to power it > >>>> off, because > >>>> + * the AFTR state won't work otherwise > >>>> + */ > >>>> + if (cpu_online(1)) { > >>>> + > >>>> + /* > >>>> + * We reach a sync point with the coupled idle > >>>> state, we know > >>>> + * the other cpu will power down itself or will > >>>> abort the > >>>> + * sequence, let's wait for one of these to > >>>> happen > >>>> + */ > >>>> + while (__raw_readl(S5P_ARM_CORE1_STATUS) & 3) { > >>>> + > >>>> + /* > >>>> + * The other cpu may skip idle and boot > >>>> back > >>>> + * up again > >>>> + */ > >>>> + if (atomic_read(&cpu1_wakeup)) > >>>> + goto abort; > >>>> + > >>>> + /* > >>>> + * The other cpu may bounce through idle > >>>> and > >>>> + * boot back up again, getting stuck in > >>>> the > >>>> + * boot rom code > >>>> + */ > >>>> + if (__raw_readl(BOOT_VECTOR) == 0) > >>>> + goto abort; > >>>> + > >>>> + cpu_relax(); > >>>> + } > >>>> + } > >>>> + > >>>> + cpu_pm_enter(); > >>>> + > >>>> + ret = cpu_suspend(1, cpu_suspend_finish); > >>>> + > >>>> + cpu_pm_exit(); > >>>> + > >>>> +abort: > >>>> + if (cpu_online(1)) { > >>>> + /* > >>>> + * Set the boot vector to something non-zero > >>>> + */ > >>>> + __raw_writel(virt_to_phys(s3c_cpu_resume), > >>>> + BOOT_VECTOR); > >>>> + dsb(); > >>>> + > >>>> + /* > >>>> + * Turn on cpu1 and wait for it to be on > >>>> + */ > >>>> + __raw_writel(0x3, S5P_ARM_CORE1_CONFIGURATION); > >>>> + while ((__raw_readl(S5P_ARM_CORE1_STATUS) & 3) != > >>>> 3) > >>>> + cpu_relax(); > >>>> + > >>>> + /* > >>>> + * Wait for cpu1 to get stuck in the boot rom > >>>> + */ > >>>> + while ((__raw_readl(BOOT_VECTOR) != 0) && > >>>> + !atomic_read(&cpu1_wakeup)) > >>>> + cpu_relax(); > >>>> + > >>>> + if (!atomic_read(&cpu1_wakeup)) { > >>>> + /* > >>>> + * Poke cpu1 out of the boot rom > >>>> + */ > >>>> + > >>>> __raw_writel(virt_to_phys(s3c_cpu_resume), > >>>> + BOOT_VECTOR); > >>>> + dsb_sev(); > >>>> + } > >>>> + > >>>> + /* > >>>> + * Wait for cpu1 to finish booting > >>>> + */ > >>>> + while (!atomic_read(&cpu1_wakeup)) > >>>> + cpu_relax(); > >>>> + } > >>>> + > >>>> + return ret; > >>>> +} > >>>> + > >>>> +static int exynos_powerdown_cpu1(void) > >>>> +{ > >>>> + int ret = -1; > >>>> + > >>>> + /* > >>>> + * Idle sequence for cpu1 > >>>> + */ > >>>> + if (cpu_pm_enter()) > >>>> + goto cpu1_aborted; > >>>> + > >>>> + /* > >>>> + * Turn off cpu 1 > >>>> + */ > >>>> + __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION); > >>>> + > >>>> + ret = cpu_suspend(0, cpu_suspend_finish); > >>>> + > >>>> + cpu_pm_exit(); > >>>> + > >>>> +cpu1_aborted: > >>>> + dsb(); > >>>> + /* > >>>> + * Notify cpu 0 that cpu 1 is awake > >>>> + */ > >>>> + atomic_set(&cpu1_wakeup, 1); > >>>> + > >>>> + return ret; > >>>> +} > >>>> + > >>>> +static int exynos_enter_aftr(struct cpuidle_device *dev, > >>>> + struct cpuidle_driver *drv, int > >>>> index) +{ > >>>> + int ret; > >>>> + > >>>> + __raw_writel(virt_to_phys(s3c_cpu_resume), BOOT_VECTOR); > >>>> + > >>>> + /* > >>>> + * Waiting all cpus to reach this point at the same > >>>> moment > >>>> + */ > >>>> + cpuidle_coupled_parallel_barrier(dev, > >>>> &exynos_idle_barrier); + > >>>> + /* > >>>> + * Both cpus will reach this point at the same time > >>>> + */ > >>>> + ret = dev->cpu ? exynos_powerdown_cpu1() : > >>>> exynos_cpu0_enter_aftr(); > >>>> + if (ret) > >>>> + index = ret; > >>>> + > >>>> + /* > >>>> + * Waiting all cpus to finish the power sequence before > >>>> going further > >>>> + */ > >>>> + cpuidle_coupled_parallel_barrier(dev, > >>>> &exynos_idle_barrier); + > >>>> + atomic_set(&cpu1_wakeup, 0); > >>>> + > >>>> + return index; > >>>> +} > >>>> + > >>>> +static struct cpuidle_driver exynos_idle_driver = { > >>>> + .name = "exynos4210_idle", > >>>> + .owner = THIS_MODULE, > >>>> + .states = { > >>>> + ARM_CPUIDLE_WFI_STATE, > >>>> + [1] = { > >>>> + .enter = > >>>> exynos_enter_aftr, > >>>> + .exit_latency = 5000, > >>>> + .target_residency = 10000, > >>>> + .flags = > >>>> CPUIDLE_FLAG_TIME_VALID | > >>>> + CPUIDLE_FLAG_COUPLED | > >>>> CPUIDLE_FLAG_TIMER_STOP, > >>>> + .name = "C1", > >>>> + .desc = "ARM power > >>>> down", > >>>> + }, > >>>> + }, > >>>> + .state_count = 2, > >>>> + .safe_state_index = 0, > >>>> +}; > >>>> + > >>>> +static int exynos_cpuidle_probe(struct platform_device *pdev) > >>>> +{ > >>>> + exynos_aftr = (void *)(pdev->dev.platform_data); > >>>> + > >>>> + return cpuidle_register(&exynos_idle_driver, > >>>> cpu_possible_mask); +} > >>>> + > >>>> +static struct platform_driver exynos_cpuidle_driver = { > >>>> + .driver = { > >>>> + .name = "exynos4210-cpuidle", > >>>> + .owner = THIS_MODULE, > >>>> + }, > >>>> + .probe = exynos_cpuidle_probe, > >>>> +}; > >>>> + > >>>> +module_platform_driver(exynos_cpuidle_driver); > >>>> -- > >>>> 1.7.9.5 > >>>> > >>>> > >>>> _______________________________________________ > >>>> linux-arm-kernel mailing list > >>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > >>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > >>> > >>> > >>> > >> > >> > > > > > > > > Best regards, Lukasz Majewski
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