Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <16ad1a82-1e99-2957-720f-08d1238edcf4@ti.com>
Date:   Thu, 31 Mar 2022 12:28:08 +0530
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [RFC] arm64: dts: ti: introduce a minimal am642 device tree
Content-Language: en-US
To:     Wadim Egorov <w.egorov@phytec.de>, Bryan Brattlof <bb@ti.com>,
        Nishanth Menon <nm@ti.com>, Tero Kristo <kristo@kernel.org>
CC:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20220321155417.13267-1-bb@ti.com>
 <73a4a16b-193a-3075-61e9-82bcf21fc7d2@phytec.de>
From:   Vignesh Raghavendra <vigneshr@ti.com>
In-Reply-To: <73a4a16b-193a-3075-61e9-82bcf21fc7d2@phytec.de>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi Wadim,

On 30/03/22 7:25 pm, Wadim Egorov wrote:
> Hi Bryan,
> 
>> +/* (optional) for console */
>> +&main_uart0 {
>> +    pinctrl-names = "default";
>> +    pinctrl-0 = <&main_uart0_pins_default>;
>> +};
>> +
>> +/* reserved for firmware */
>> +&main_uart1 {
>> +    status = "reserved";
>> +};
> 
> k3-image-gen says UART0 is used as a debug interface. See
> 
> 
> https://git.ti.com/cgit/k3-image-gen/k3-image-gen/tree/soc/am64x/evm/board-cfg.c#n81
> 
> 
> So it seems that you can enable uart1 here. But people may run into a
> conflict with uart0 and k3-image-gen compiled with ENABLE_TRACE=1.
> 
> If I am wrong, can you please clarify why you mark uart1 as reserved.
> 

We just seem to have same macro shared across multiple SoCs,
BOARDCFG_TRACE_DST_UART0 means logs are also directed to UART. Instance
of UART used for logging is platform specific.

On AM64 SYSFW logs are directed to MAIN UART1 (MAIN UART0 is used for
linux console). I will work internally and get SYSFW documentation
updated to reflect the same. Thanks!

Regards
Vignesh