[PATCHv6] ARM: dts: add exynos5422-cpus.dtsi to correct cpu order

[Krzysztof Kozlowski]

2015-07-14 21:28 GMT+09:00 Chanho Park <parkch98 at gmail.com>:
> Hi,
>
> On Tue, Jul 14, 2015 at 5:23 PM, Kukjin Kim <kgene at kernel.org> wrote:
>> Chanho Park wrote:
>>>
>>> Hi Kukjin,
>>>
>>> On Tue, Jul 14, 2015 at 2:04 PM, Kukjin Kim <kgene at kernel.org> wrote:
>>> > Krzysztof Kozlowski wrote:
>>> >>
>>> >> On 14.07.2015 09:24, Chanho Park wrote:
>>> >> > The odroid-xu3 board which is based on exynos5422 not exynos5800 is
>>> >> > booted from cortex-a7 core unlike exynos5800. The odroid-xu3's cpu order
>>> >> > is quite strange. cpu0 and cpu5-7 are cortex-a7 cores and cpu1-4 are
>>> >> > cortex-a15 cores. To correct this mis-odering, I added exynos5422-cpus.dtsi
>>> >> > and reversing cpu orders from exynos5420. Now, cpu0-3 are cortex-a7 and
>>> >> > cpu4-7 are cortex-a15.
>>> >> >
>>> >> > Reviewed-by: Krzysztof Kozlowski <k.kozlowski at samsung.com>
>>> >> > Signed-off-by: Chanho Park <parkch98 at gmail.com>
>>> >> > ---
>>
>> [...]
>>
>>> >> >
>>> >> > Secondary cpu booting problem[1] is not resolved yet. Need more investigations
>>> >> > to work booting 8 cores correctly.
>>> >> >
>>> >> > [1]: http://www.spinics.net/lists/linux-samsung-soc/msg45525.html
>>> >> >
>>> >> >  arch/arm/boot/dts/exynos5422-cpus.dtsi             | 81 ++++++++++++++++++++++
>>> >> >  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi |  1 +
>>> >> >  2 files changed, 82 insertions(+)
>>> >> >  create mode 100644 arch/arm/boot/dts/exynos5422-cpus.dtsi
>>> >>
>>> >> Thanks, applied to my tree. I'll send it to Kukjin for v4.3 unless he
>>> >> picks it also.
>>> >>
>>> > Well, let me see. I'm thinking we need to sort out the cpu ordering and dtsi
>>> > inclusions for exynos5420, 5422 and 5800 related to DT files.
>>> >
>>> > See,
>>> >
>>> > 1) exynos5420 DT (cpu0~3: a15, cpu 4~7: a7)
>>> > 2) exynos5800 DT is including exynos5420 DT
>>> > 3) exynos5422 and exynos5800 based boards are including exynos5800 DT.
>>> >
>>> > Then making exynos5422-cpus DT for exynos5422 based boards?
>>> > (cpu0~3: a7, cpu4~7: a15)
>>> >
>>> > I think, it could cause confusion when new board based on them are added
>>> > because it's not clear and the boot cpu could be selected by bootloader part.
>>>
>>> The iROM will check the GPIO pin to select which core is run as cpu0.
>>> I think no one will change the GPIO pin if a new board which is based
>>> on exynos5422 :)
>>>
>> Yes, I know the boot sequence and it means it depends on board configuration
>> not SoC. That’s why I'm saying it should be handled in board DT file. I think,
>> most of current exynos big.LITTLE model should do if it could be changed
>> according to board configuration.
>
> I also agreed it's not a SoC configuration since second
> patch(exynos5422.dtsi -> exynos5422-cpu.dtsi).
>
>>
>>> >
>>> > So how about creating exynos5422-cpus and exynos5420-cpus then including the
>>> > cpus DT file in each board accordingly?
>>> >
>>> > Or more clear way to avoid confusion?
>>>
>>> In this situation, all exynos5422 boards(odroid xu3 series and mobile
>>> phone) have same cpu configurations. If we move the exynos5420 cpu
>>> configuration from exynos5420.dtsi, we should change all dts which
>>> including exynos5420.dtsi.
>>
>> Maybe same board configuration. Just adding inclusion should be fine at this
>> moment.
>>
>>> I think we'd better to defer the change until a new exynos5422 board
>>> which has different cpu configurations is added.
>>>
>> I mean, according to current inclusion of exynos5422 based boards' DT file, it
>> is including exynos5420 DT via exynos5800 DT and then override different cpu
>> ordering (5422-cpu DT) because of different board configuration (just GPIO
>> value) and it is not a good way in this case.
>
> Actually, I don't want to disturb current dts hierarchy even though it
> looks strange. The common features of exynos5800 and exynos5422 should
> be in the exynos5800.dtsi because they shared many things except the
> cpu order.
> Please consider the exynos5422-cpu.dtsi is just board configurations
> to represent cpu order.

Dear Chanho and Kukjin,

Did you reached a conclusion on this patch?

Best regards,
Krzysztof