Subject: Re: [PATCH v2] ARC: axs10x - add Ethernet PHY description in .dts

From: Giuseppe CAVALLARO <[email-masked]>
Date: Wed, 6 Apr 2016 16:56:48 +0200

On 4/6/2016 11:12 AM, Vineet Gupta wrote:
> Hi,
>
> On Thursday 17 March 2016 03:11 PM, Alexey Brodkin wrote:
>> Following commit broke DW GMAC functionality on AXS10x boards:
>> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e34d65696d2ef13dc32f2a162556c86c461ed763
>>
>> That's what happens on eth0 up:
>> --------------------------->8------------------------
>> libphy: PHY stmmac-0:ffffffff not found
>> eth0: Could not attach to PHY
>> stmmac_open: Cannot attach to PHY (error: -19)
>> --------------------------->8------------------------
>>
>> Simplest solution is to add PHY description in board's .dts.
>> And so we do here.
>>
>> Signed-off-by: Alexey Brodkin <[email-masked]>
>> Cc: Rob Herring <[email-masked]>
>> Cc: Phil Reid <[email-masked]>
>> Cc: David S. Miller <[email-masked]>
>> Cc: [email-masked]
>> Cc: [email-masked]
>> Cc: [email-masked] # 4.5.x
>> Cc: Sergei Shtylyov <[email-masked]>
>> ---
>>
>> Changes v1 -> v2:
>>   * PHY node name changed to match real PHY number being used (Sergei)
>>
>>   arch/arc/boot/dts/axs10x_mb.dtsi | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/arch/arc/boot/dts/axs10x_mb.dtsi b/arch/arc/boot/dts/axs10x_mb.dtsi
>> index 44a578c..ab5d570 100644
>> --- a/arch/arc/boot/dts/axs10x_mb.dtsi
>> +++ b/arch/arc/boot/dts/axs10x_mb.dtsi
>> @@ -47,6 +47,14 @@
>>   			clocks = <&apbclk>;
>>   			clock-names = "stmmaceth";
>>   			max-speed = <100>;
>> +			mdio0 {
>> +				#address-cells = <1>;
>> +				#size-cells = <0>;
>> +				compatible = "snps,dwmac-mdio";
>> +				phy1: ethernet-phy@1 {
>> +					reg = <1>;
>> +				};
>> +			};
>>   		};
>>
>>   		ehci@0x40000 {
>
>
> So above DT fix for ARC went into 4.6-rc1 and ethernet was still broken on axs103
> board.
>
> ---------->8-------------
> libphy: PHY stmmac-0:ffffffff not found
> eth0: Could not attach to PHY
> stmmac_open: Cannot attach to PHY (error: -19)
> ---------->8-------------
>
> On 4.6-rc2 if I revert the DT change, ethernet works again.
>
> @Giuseppe, @Phil, @Gabriel, I see you have made changes in that area. I presume
> that above revert is the right/sufficient thing or do we need to do something else
> as well.

hmm I think so, we pushed all the changes in net-next to fix the MDIO
initialization according to the different DT parameter settings. So
unless there is some other case to cover, I think that the best
approach is to do the revert.

pls, let me know

peppe

> TIA,
> -Vineet