Re: [2/3] soc: samsung: Do not build ARMv7 PMU drivers on ARMv8

[Alim Akhtar <alim.akhtar@samsung.com>]

Hi Krzysztof,

On 03/12/2017 03:08 AM, Krzysztof Kozlowski wrote:
> The Exynos Power Management Unit (PMU) drivers contain quite large
> static arrays of register values necessary for given Exynos SoC to enter
> low power mode.  All this data is useless for ARMv8 SoC like
> Exynos5433, because the image will not be shared between ARMv7 and
> ARMv8.
>
> Add additional Kconfig symbol for selecting the SoC-specific driver
> addons thus skipping the useless data in the final image (this is
> similar approach to chosen for Exynos clock controller drivers):
>  - exynos-pmu driver will be compiled on both architectures ARMv7
>    and ARMv8,
>  - additional driver_data for ARMv7 SoCs will not be built on ARMv8
>    and a macro will return NULL for them in of_device_id - this should
>    be safe as these compatibles cannot match on ARMv7 and driver
>    anyway handles NULL driver_data,
>  - on ARMv8 compile only exynos-pmu driver which exposes the
>    syscon-regmap for PMU address space.
>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/soc/samsung/Kconfig      |  8 +++++++-
>  drivers/soc/samsung/Makefile     |  4 +++-
>  drivers/soc/samsung/exynos-pmu.c | 22 ++++++++++++++++------
>  drivers/soc/samsung/exynos-pmu.h |  3 +++
>  4 files changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
> index 245533907d1b..8b25bd55e648 100644
> --- a/drivers/soc/samsung/Kconfig
> +++ b/drivers/soc/samsung/Kconfig
> @@ -8,7 +8,13 @@ if SOC_SAMSUNG
>
>  config EXYNOS_PMU
>  	bool "Exynos PMU controller driver" if COMPILE_TEST
> -	depends on (ARM && ARCH_EXYNOS) || ((ARM || ARM64) && COMPILE_TEST)
> +	depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST)
> +	select EXYNOS_PMU_ARM_DRIVERS if ARM && ARCH_EXYNOS
> +

In general this patch look ok, but I was think we should make these 
configs configurable via _menuconfig_. Currently these are visible only 
if COMPILE_TEST is enabled.
Recently I was working on adding PMU support for Exynos7 and I face 
issues when I want to disable this option and re-enable it for testing 
purpose.

> +# There is no need to enable these drivers for ARMv8
> +config EXYNOS_PMU_ARM_DRIVERS
> +	bool "Exynos PMU ARMv7-specific driver extensions" if COMPILE_TEST
> +	depends on EXYNOS_PMU
>
>  config EXYNOS_PM_DOMAINS
>  	bool "Exynos PM domains" if COMPILE_TEST
> diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
> index 3619f2ecddaa..4d7694a4e7a4 100644
> --- a/drivers/soc/samsung/Makefile
> +++ b/drivers/soc/samsung/Makefile
> @@ -1,3 +1,5 @@
> -obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o exynos3250-pmu.o exynos4-pmu.o \
> +obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
> +
> +obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \
>  					exynos5250-pmu.o exynos5420-pmu.o
>  obj-$(CONFIG_EXYNOS_PM_DOMAINS) += pm_domains.o
> diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
> index 56d9244ff981..bd4a76f27bc2 100644
> --- a/drivers/soc/samsung/exynos-pmu.c
> +++ b/drivers/soc/samsung/exynos-pmu.c
> @@ -69,27 +69,37 @@ void exynos_sys_powerdown_conf(enum sys_powerdown mode)
>  }
>
>  /*
> + * Split the data between ARM architectures because it is relatively big
> + * and useless on other arch.
> + */
> +#ifdef CONFIG_EXYNOS_PMU_ARM_DRIVERS
> +#define exynos_pmu_data_arm_ptr(data)	(&data)
> +#else
> +#define exynos_pmu_data_arm_ptr(data)	NULL
> +#endif
> +
> +/*
>   * PMU platform driver and devicetree bindings.
>   */
>  static const struct of_device_id exynos_pmu_of_device_ids[] = {
>  	{
>  		.compatible = "samsung,exynos3250-pmu",
> -		.data = &exynos3250_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos3250_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos4210-pmu",
> -		.data = &exynos4210_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos4210_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos4212-pmu",
> -		.data = &exynos4212_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos4212_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos4412-pmu",
> -		.data = &exynos4412_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos4412_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos5250-pmu",
> -		.data = &exynos5250_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos5250_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos5420-pmu",
> -		.data = &exynos5420_pmu_data,
> +		.data = exynos_pmu_data_arm_ptr(exynos5420_pmu_data),
>  	}, {
>  		.compatible = "samsung,exynos5433-pmu",
So, as I understand, the idea here to use something like
	.data = &exynos5433_pmu_data or so in case ARMv8?

>  	},
> diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h
> index a469e366fead..40d4229abfb5 100644
> --- a/drivers/soc/samsung/exynos-pmu.h
> +++ b/drivers/soc/samsung/exynos-pmu.h
> @@ -31,6 +31,8 @@ struct exynos_pmu_data {
>  };
>
>  extern void __iomem *pmu_base_addr;
> +
> +#ifdef CONFIG_EXYNOS_PMU_ARM_DRIVERS
>  /* list of all exported SoC specific data */
>  extern const struct exynos_pmu_data exynos3250_pmu_data;
>  extern const struct exynos_pmu_data exynos4210_pmu_data;
> @@ -38,6 +40,7 @@ extern const struct exynos_pmu_data exynos4212_pmu_data;
>  extern const struct exynos_pmu_data exynos4412_pmu_data;
>  extern const struct exynos_pmu_data exynos5250_pmu_data;
>  extern const struct exynos_pmu_data exynos5420_pmu_data;
> +#endif
>
>  extern void pmu_raw_writel(u32 val, u32 offset);
>  extern u32 pmu_raw_readl(u32 offset);
>