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Date:   Wed, 24 Aug 2022 14:45:08 +0530
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Subject: Re: [PATCH 4/4] arch: arm64: ti: Add support for J784s4 EVM board
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Nishanth Menon <nm@ti.com>
CC:     Apurva Nandan <a-nandan@ti.com>, Tero Kristo <kristo@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-gpio@vger.kernel.org>, Hari Nagalla <hnagalla@ti.com>
References: <20220819190054.31348-1-a-nandan@ti.com>
 <20220819190054.31348-5-a-nandan@ti.com>
 <6c89f254-185a-4046-2bf0-a9f85713858e@linaro.org>
 <20220824050627.nh7d4blrsfbxrvuh@clicker>
 <734b1e1c-2416-0684-287e-a96b86a416a2@ti.com>
 <81134eb9-2b7d-05bc-3035-a47f020861a8@linaro.org>
From:   Vignesh Raghavendra <vigneshr@ti.com>
In-Reply-To: <81134eb9-2b7d-05bc-3035-a47f020861a8@linaro.org>
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On 24/08/22 12:42, Krzysztof Kozlowski wrote:
> On 24/08/2022 08:33, Vignesh Raghavendra wrote:
>> Hi Krzysztof,
>>
>> On 24/08/22 10:36, Nishanth Menon wrote:
>>> On 13:21-20220823, Krzysztof Kozlowski wrote:
>>>>> +
>>>>> +/ {
>>>>> +	compatible = "ti,j784s4-evm", "ti,j784s4";
>>>>> +	model = "Texas Instruments J784S4 EVM";
>>>>> +
>>>>> +	chosen {
>>>>> +		stdout-path = "serial2:115200n8";
>>>>> +		bootargs = "console=ttyS2,115200n8 earlycon=ns16550a,mmio32,0x2880000";
>>>>
>>>> earlycon is not a property of hardware. Console is defined in
>>
>> earlycon is helpful for debugging early crashes. How is it any different
>> from "console =" property as described in
>> Documentation/devicetree/usage-model.rst?
> 
> choice of console is needed for basic operation and is chosen based on
> current hardware setup. earlycon is purely for debugging and should be
> enabled only when debugging is intended, not on mainline wide-available
> sources.
> 
>>
>>>> stdout-path, so please drop entire bootargs.
>>>
>>> We will probably have to cleanup elsewhere as well - point noted.
>>>
>>
>> Whats the alternative to pass default bootargs to kernel if bootloader
>> does not pass bootargs via cmdline? I see quite a few dts file use
>> bootargs = "earlycon" at least
> 
> Uboot, your own out-of-tree testing patches? What's the point to have
> earlycon available for every user which does not want to debug?
> 
> Sorry, but bootargs are not accepted in DTS. We have several discussions
> around it over time...

Understood, just wanted to make sure what the latest stance is, as I see
lot of files in arm64 dts folder still use bootargs and earlycon. Thanks
for the clarification!

-- 
Regards
Vignesh