[PATCH] ARM: exynos_defconfig: Enable big.LITTLE CPUidle support

[Krzysztof Kozlowski]

2015-08-29 18:33 GMT+09:00 Javier Martinez Canillas <javier at osg.samsung.com>:
> Hello Krzysztof,
>
> On 08/29/2015 11:01 AM, Krzysztof Kozlowski wrote:
>> W dniu 28.08.2015 o 17:16, Javier Martinez Canillas pisze:
>>> Some Exynos big.LITTLE boards (i.e: Exynos5420 and Exynos5800 based
>>> Chromebooks) have proper firmware that allow the big.LITTLE CPUidle
>>> driver to work correctly, so enable support for this.
>>>
>>> Signed-off-by: Javier Martinez Canillas <javier at osg.samsung.com>
>>>
>>> ---
>>> Kukjin and Krzysztof,
>>>
>>> As you know there are other boards like the Exynos5422 based Odroid XU{3,4}
>>> whose firmware is broken due leaving CCI in secure mode which means that the
>>> kernel MCPM support can't properly manage CCI.
>>>
>>> So if you pick this patch, it should be tested in kernelci before appearing
>>> in linux-next to prevent any boot issues.
>>>
>>> But if that happens, I believe that is better to do a fix / workaround in
>>> those broken platforms since nothing prevents users to enable this option
>>> anyways. For example the CCI device node could be disabled in the DTS.
>>>
>>>  arch/arm/configs/exynos_defconfig | 1 +
>>>  1 file changed, 1 insertion(+)
>>
>> On Odroid XU3L (next-20150828, Hardkernel u-boot) boot hangs just after:
>>
>
> Thanks for testing, I was expecting that is just that I don't have a
> Odroid XU{3,4} board for test here, I guess I should get one.
>
>> [    2.568650] dwmmc_exynos 12200000.mmc: num-slots property not found,
>> assuming 1 slot is available
>>
>> ... so no. NACK :). First the boards, firmware, bootloader or kernel
>
> Agreed with the nack :)
>
>> code have to be fixed.
>>
>
> Or disable CCI, could you please test the following patch [0] so I
> can post it properly?

It fixes the boot hang but causes other issues. Not all CPUs boot (I
tested it on Chanho Park's patch for fixing CPU boot with SWRESET):
[    0.010781] CPU0: update cpu_capacity 448
[    0.010839] CPU0: thread -1, cpu 0, socket 1, mpidr 80000100
[    0.011098] Setting up static identity map for 0x40008280 - 0x400082d8
[    0.056329] CPU1: update cpu_capacity 448
[    0.056337] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[    0.071100] CPU2: update cpu_capacity 448
[    0.071107] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[    0.086103] CPU3: update cpu_capacity 448
[    0.086111] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[    0.101100] CPU4: update cpu_capacity 1535
[    0.101108] CPU4: thread -1, cpu 0, socket 0, mpidr 80000000
[    1.115009] CPU5: failed to boot: -110
[    2.130019] CPU6: failed to boot: -110
[    3.145049] CPU7: failed to boot: -110
[    3.145151] Brought up 5 CPUs
[    3.145196] SMP: Total of 5 processors activated (240.00 BogoMIPS).
[    3.145251] CPU: WARNING: CPU(s) started in wrong/inconsistent
modes (primary CPU mode 0x13)
[    3.145327] CPU: This may indicate a broken bootloader or firmware.
[    3.149347] devtmpfs: initialized

Best regards,
Krzysztof


>
>> Best regards,
>> Krzysztof
>>
>
> Best regards,
> --
> Javier Martinez Canillas
> Open Source Group
> Samsung Research America
>
> [0]:
> From 0fc5649b8d939ccfb7d3be1aa09df5e1f89a5a82 Mon Sep 17 00:00:00 2001
> From: Javier Martinez Canillas <javier at osg.samsung.com>
> Date: Sat, 29 Aug 2015 11:21:39 +0200
> Subject: [RFT PATCH] ARM: dts: Disable CCI support for Odroid XU{3,4} boards
>
> The Exynos5422 based Odroid XU{3,4} boards have a broken firmware that
> leaves CCI in secure mode which means that the kernel MCPM support can
> not properly manage CCI. This causes the machine to hang when entering
> into low power states for example triggered by the b.L CPUidle driver.
>
> The patch is based on commit 25217fef3551 ("ARM: dts: disable CCI on
> exynos5420 based arndale-octa")
>
> Signed-off-by: Javier Martinez Canillas <javier at osg.samsung.com>
> ---
>  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> index dd8bc86d9de4..1e076458fab6 100644
> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> @@ -525,3 +525,7 @@
>         vdd33-supply = <&ldo9_reg>;
>         vdd10-supply = <&ldo11_reg>;
>  };
> +
> +&cci {
> +       status = "disabled";
> +};
> --
> 2.4.3
> --
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