[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <0512d57f-af22-4bd8-8266-33d943d7eb4a@ti.com>
Date: Mon, 11 Mar 2024 16:14:46 +0530
From: Chintan Vankar <c-vankar@...com>
To: Andrew Davis <afd@...com>, Peter Rosin <peda@...ntia.se>,
Greg
Kroah-Hartman <gregkh@...uxfoundation.org>,
Conor Dooley
<conor+dt@...nel.org>,
Krzysztof Kozlowski
<krzysztof.kozlowski+dt@...aro.org>,
Rob Herring <robh+dt@...nel.org>, Tero
Kristo <kristo@...nel.org>,
Vignesh Raghavendra <vigneshr@...com>, Nishanth
Menon <nm@...com>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <srk@...com>,
<s-vadapalli@...com>, <r-gunasekaran@...com>, <danishanwar@...com>
Subject: Re: [PATCH v4 2/6] arm64: dts: ti: k3-j784s4: Add alias to MCU CPSW2G
On 31/01/24 21:06, Andrew Davis wrote:
> On 1/31/24 4:14 AM, Chintan Vankar wrote:
>> Add alias for the MCU CPSW2G port to enable Linux to fetch MAC Address
>> for the port directly from U-Boot.
>
> Could you explain *how* this alias allows Linux to fetch a MAC
> address from U-Boot? Sounds like we are doing something hacky here..
>
Using "probe_daughtercards()" function U-Boot parses MAC addresses from
EEPROM, then it internally calls "eth_env_set_enetaddr_by_index()"
function which stores these MAC addresses into environment variables
ethaddr, eth1addr, eth2addr and so on based on number of ports.
U-Boot loads DTB during boot process, and it calls
"fdt_fixup_ethernet()" function, which uses environment variables to
update MAC addresses of ethernet ports as specified in the aliases
section.
> Why can't Linux fetch the MAC from efuses the same way U-Boot does,
Linux can fetch the MAC address from efuses if "ti,syscon-efuse"
property is enabled.
> what happens if I don't use U-Boot to boot?
If you don't use U-Boot to boot then the equivalent of
"probe_daughtercards()" has to be implemented which is currently
missing.
>
> Andrew
>
>> ---
>> arch/arm64/boot/dts/ti/k3-j784s4-evm.dts | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
>> b/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
>> index f34b92acc56d..b74f7d3025de 100644
>> --- a/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
>> +++ b/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
>> @@ -27,6 +27,7 @@ aliases {
>> mmc1 = &main_sdhci1;
>> i2c0 = &wkup_i2c0;
>> i2c3 = &main_i2c0;
>> + ethernet0 = &mcu_cpsw_port1;
>> };
>> memory@...00000 {
Powered by blists - more mailing lists