Re: [PATCH v4 12/13] cpuidle: mvebu: Add initial CPU idle support for Armada 370/XP SoC

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 02/13/2014 06:33 PM, Gregory CLEMENT wrote:
> Add the wfi, cpu idle and cpu deep idle power states support for the
> Armada XP SoCs.
>
> All the latencies and the power consumption values used at the
> "armada_370_xp_idle_driver" structure are preliminary and will be
> modified in the future after running some measurements and analysis.
>
> Based on the work of Nadav Haklai.
>
> Signed-off-by: Nadav Haklai <nadavh@marvell.com>
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
>   drivers/cpuidle/Kconfig.arm             |   5 ++
>   drivers/cpuidle/Makefile                |   1 +
>   drivers/cpuidle/cpuidle-armada-370-xp.c | 120 ++++++++++++++++++++++++++++++++
>   3 files changed, 126 insertions(+)
>   create mode 100644 drivers/cpuidle/cpuidle-armada-370-xp.c
>
> diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
> index d988948a89a0..f377eb0840e3 100644
> --- a/drivers/cpuidle/Kconfig.arm
> +++ b/drivers/cpuidle/Kconfig.arm
> @@ -1,6 +1,11 @@
>   #
>   # ARM CPU Idle drivers
>   #
> +config ARM_ARMADA_370_XP_CPUIDLE
> +	bool "CPU Idle Driver for Armada 370/XP family processors"
> +	depends on ARCH_MVEBU
> +	help
> +	  Select this to enable cpuidle on Armada 370/XP processors.
>
>   config ARM_BIG_LITTLE_CPUIDLE
>   	bool "Support for ARM big.LITTLE processors"
> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
> index f71ae1b373c5..9902d052bd87 100644
> --- a/drivers/cpuidle/Makefile
> +++ b/drivers/cpuidle/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
>
>   ##################################################################################
>   # ARM SoC drivers
> +obj-$(CONFIG_ARM_ARMADA_370_XP_CPUIDLE) += cpuidle-armada-370-xp.o
>   obj-$(CONFIG_ARM_BIG_LITTLE_CPUIDLE)	+= cpuidle-big_little.o
>   obj-$(CONFIG_ARM_HIGHBANK_CPUIDLE)	+= cpuidle-calxeda.o
>   obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
> diff --git a/drivers/cpuidle/cpuidle-armada-370-xp.c b/drivers/cpuidle/cpuidle-armada-370-xp.c
> new file mode 100644
> index 000000000000..57c69812e79d
> --- /dev/null
> +++ b/drivers/cpuidle/cpuidle-armada-370-xp.c
> @@ -0,0 +1,120 @@
> +/*
> + * Marvell Armada 370 and Armada XP SoC cpuidle driver
> + *
> + * Copyright (C) 2013 Marvell
> + *
> + * Nadav Haklai <nadavh@marvell.com>
> + * Gregory CLEMENT <gregory.clement@free-electrons.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2.  This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + *
> + * Maintainer: Gregory CLEMENT <gregory.clement@free-electrons.com>
> + */

Hi Gregory,

> +#include <linux/cpu_pm.h>
> +#include <linux/cpuidle.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/suspend.h>
> +#include <asm/suspend.h>
> +#include <linux/smp.h>
> +#include <asm/cpuidle.h>
> +#include <asm/smp_plat.h>
> +#include <linux/platform_device.h>
> +#include <asm/cp15.h>
> +#include <asm/cacheflush.h>

the convention for the drivers inside this directory is to not include 
<asm/*>.

> +#define ARMADA_370_XP_MAX_STATES	3
> +#define ARMADA_370_XP_FLAG_DEEP_IDLE	0x10000
> +extern void armada_370_xp_pmsu_idle_prepare(bool deepidle);
> +extern void ll_clear_cpu_coherent(void);
> +extern void ll_set_cpu_coherent(void);

Here you have to declare three low level functions which should not be 
visible in this driver.

I think you can go one step more in the code encapsulation by doing like 
the cpuidle-at91 driver:
	* Move armada_370_xp_cpu_suspend inside arch/arm/mach-mvebu/pm.c or 
whereever you want
	* Assign the suspend function to the platform device data file
	* Get the suspend function as a callback for suspend from the field above


> +noinline static int armada_370_xp_cpu_suspend(unsigned long deepidle)
> +{
> +	armada_370_xp_pmsu_idle_prepare(deepidle);
> +
> +	v7_exit_coherency_flush(all);
> +
> +	ll_clear_cpu_coherent();
> +
> +	dsb();
> +
> +	wfi();
> +
> +	ll_set_cpu_coherent();
> +
> +	asm volatile(
> +	"mrc	p15, 0, %0, c1, c0, 0 \n\t"
> +	"tst	%0, #(1 << 2) \n\t"
> +	"orreq	r0, %0, #(1 << 2) \n\t"
> +	"mcreq	p15, 0, %0, c1, c0, 0 \n\t"
> +	"isb	"
> +	: : "r" (0));
> +
> +	return 0;
> +}
> +
> +static int armada_370_xp_enter_idle(struct cpuidle_device *dev,
> +				struct cpuidle_driver *drv,
> +				int index)
> +{
> +	bool deepidle = false;
> +	cpu_pm_enter();
> +
> +	if (drv->states[index].flags & ARMADA_370_XP_FLAG_DEEP_IDLE)
> +		deepidle = true;
> +
> +	cpu_suspend(deepidle, armada_370_xp_cpu_suspend);
> +
> +	cpu_pm_exit();
> +
> +	return index;
> +}
> +
> +static struct cpuidle_driver armada_370_xp_idle_driver = {
> +	.name			= "armada_370_xp_idle",
> +	.states[0]		= ARM_CPUIDLE_WFI_STATE,
> +	.states[1]		= {
> +		.enter			= armada_370_xp_enter_idle,
> +		.exit_latency		= 10,
> +		.power_usage		= 50,
> +		.target_residency	= 100,
> +		.flags			= CPUIDLE_FLAG_TIME_VALID,
> +		.name			= "MV CPU IDLE",
> +		.desc			= "CPU power down",
> +	},
> +	.states[2]		= {
> +		.enter			= armada_370_xp_enter_idle,
> +		.exit_latency		= 100,
> +		.power_usage		= 5,
> +		.target_residency	= 1000,
> +		.flags			= CPUIDLE_FLAG_TIME_VALID |
> +						ARMADA_370_XP_FLAG_DEEP_IDLE,
> +		.name			= "MV CPU DEEP IDLE",
> +		.desc			= "CPU and L2 Fabric power down",
> +	},
> +	.state_count = ARMADA_370_XP_MAX_STATES,
> +};
> +
> +static int armada_370_xp_cpuidle_probe(struct platform_device *pdev)
> +{
> +	return cpuidle_register(&armada_370_xp_idle_driver, NULL);
> +}
> +
> +static struct platform_driver armada_370_xp_cpuidle_plat_driver = {
> +	.driver = {
> +		.name = "cpuidle-armada-370-xp",
> +		.owner = THIS_MODULE,
> +	},
> +	.probe = armada_370_xp_cpuidle_probe,
> +};
> +
> +module_platform_driver(armada_370_xp_cpuidle_plat_driver);
> +
> +MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
> +MODULE_DESCRIPTION("Armada 370/XP cpu idle driver");
> +MODULE_LICENSE("GPL");
>


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