linux-kernel - Re: [PATCH 1/2] arm64: dts: mt8173: elm: Set uart0 to mmio32 iotype

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 10 Sep 2020 10:16:55 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Devicetree List <devicetree@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] arm64: dts: mt8173: elm: Set uart0 to mmio32 iotype

Hi Hsin-Yi,

On 10/9/20 9:57, Hsin-Yi Wang wrote:
> On Thu, Sep 10, 2020 at 3:20 PM Enric Balletbo i Serra
> <enric.balletbo@...labora.com> wrote:
>>
>> Hi Hsin-Yi,
>>
>> On 10/9/20 7:46, Hsin-Yi Wang wrote:
>>> Set uart0 iotype to mmio32 to make earlycon work with stdout-path.
>>>
>>> Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
>>> ---
>>>  arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi b/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
>>> index a5a12b2599a4a..d54e62f72c65d 100644
>>> --- a/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
>>> +++ b/arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi
>>> @@ -1160,6 +1160,8 @@ &thermal {
>>>  };
>>>
>>>  &uart0 {
>>> +     reg-io-width = <4>;
>>> +     reg-shift = <2>;
>>
>> I am wondering if these properties are common enough to go to mt8173.dtsi
>> instead of here.
>>
> Since stdout-path is set on elm.dtsi (using uart0), so I add this
> attribute here.
> 

Why needs to be defined in the same place that stdout-path is set?

My guess is that reg-io-width and reg-shift are SoC specific, as they define how
the IO access to the register is done. In fact, I think that these properties
should be added in all the uarts, not only the one that has defined the stdout-path.

Cheers,
  Enric