On 03/14/2017 02:44 PM, Krzysztof Kozlowski wrote: > On Tue, Mar 14, 2017 at 10:40 AM, Alim Akhtar <alim.akhtar@xxxxxxxxxxx> wrote: >> >> >> On 03/14/2017 01:32 PM, Krzysztof Kozlowski wrote: >>> On Tue, Mar 14, 2017 at 9:51 AM, Alim Akhtar <alim.akhtar@xxxxxxxxxxx> wrote: >>>> 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@xxxxxxxxxx> >>>>> --- >>>>> 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. >>> >>> These drivers are not available in menuconfig on purpose - these are >>> essential parts of SoC. Without them usually something will not work >>> so user should not be able to disable them. For all of such drivers, >>> we use the SELECT from mach approach. >>> >> Well, what you are saying is very subjective. In past I have face issues >> where to isolate or narrow down some issue, we do need to play with PMU >> and power domains. So, having a configurable option won't hurt here. >> Anyway if you (or anyone else) strongly feel we should be following >> "SELECT from MACH approach" then lets follow it. > > For ARMv7, in the past you could not do this. It behaved (almost) > always the same as it is now. The PMU driver was being compiled in if > ARCH_EXYNOS is selected. > > On ARMv8 - Exynos7 - there was no PMU driver so indeed this behavior > changes. However PMU driver now is necessary for pinctrl (and actually > for some others referring by syscon) so really you cannot disable it > and expect things to work. Menuconfig serves such purpose - user > (distro config developer) can choose what he wants but he wants to > boot the kernel. People in general and people setting up configs for > distro usually do not know all the subtle SoC submodule relations for > all of the SoCs. That is our responsibility to provide them something > which is usable. > > On the other hand, for debugging we always had to change some things. > That's debugging. > Ok, got it. Feel free to add Reviewed-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx> > Best regards, > Krzysztof > > > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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