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Date: Thu, 11 Dec 2014 14:02:53 +0100
Message-ID: <CABuKBeLOcr_CViztHidiXFUzjJ6keJgRrLiEr997Qr34THqicQ@mail.gmail.com>
Subject: Re: [PATCH 3/4] arm64: dts: Add mediatek MT8173 SoC and evaluation
 board dts and Makefile
From: Matthias Brugger <matthias.bgg@gmail.com>
To: Eddie Huang <eddie.huang@mediatek.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>, Rob Herring <robh+dt@kernel.org>,
        Jason Cooper <jason@lakedaemon.net>,
        srv_heupstream <srv_heupstream@mediatek.com>,
        Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Kumar Gala <galak@codeaurora.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Thomas Gleixner <tglx@linutronix.de>, Olof Johansson <olof@lixom.net>,
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	<linux-arm-kernel@lists.infradead.org>,
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        =?UTF-8?B?WUggQ2hlbiAo6Zmz5pix6LGqKQ==?= <yh.chen@mediatek.com>
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Sender: linux-kernel-owner@vger.kernel.org

Hi Eddie,

2014-12-11 13:47 GMT+01:00 Eddie Huang <eddie.huang@mediatek.com>:
> On Wed, 2014-12-10 at 15:50 +0100, Matthias Brugger wrote:
>> 2014-12-10 15:27 GMT+01:00 Yingjoe Chen <yingjoe.chen@mediatek.com>:
>> >
>> > Hi,
>> >
>> > On Wed, 2014-12-10 at 18:50 +0800, Eddie Huang wrote:
>> > <...>
>> >> diff --git a/arch/arm64/boot/dts/mt8173-evb.dts b/arch/arm64/boot/dts/mt8173-evb.dts
>> >> new file mode 100644
>> >> index 0000000..adf26dd
>> >> --- /dev/null
>> >> +++ b/arch/arm64/boot/dts/mt8173-evb.dts
>> > <...>
>> >> +     timer {
>> >> +             compatible = "arm,armv8-timer";
>> >> +             interrupt-parent = <&gic>;
>> >> +             interrupts = <1 13 0x8>,
>> >> +                          <1 14 0x8>,
>> >> +                          <1 11 0x8>,
>> >> +                          <1 10 0x8>;
>> >> +             clock-frequency = <13000000>;
>> >
>> > I believe our firmware doesn't need this line. Please remove it.
>>
>> The point here would be to know if you need to enable a special timer
>> from the mtk-timer block to get the arch timer working.
>> In any case, you will need some sort of timer. This dts does not
>> describe the mtk-timer (may in the mt8173 it does not exist) but
>> defines the clocks clk26m and clk32k. So if you don't use the
>> mtk-timer, please remove the clocks as there isn't a block using them.
>>
>
> MT8173 has two timer set: CPUGPT and APBGPT, and use CPUGPT to enable
> arch_timer. Previous series only have APBGPT. MT8173 still need enable
> CPUGPT to get arch timer working, we put this in loader, and transparent
> to kernel. So I will remove clk26m and clk32k in next version.

Ok, so if this is done in the bootloader, there shouldn't be a problem
then. Perfect.

Just one more comment on the dts nodes. Can you use the makros defined
for the interrupt type
e.g "GIC_PPI 14 IRQ_TYPE_LEVEL_LOW" instead of "1 14 0x8". This makes
the dts easier to read.

Thanks,
Matthias

>


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