On 22.05.19 18:32, Andrew Lunn wrote:
> On Wed, May 22, 2019 at 10:33:29AM +0200, Benjamin Beckmeyer wrote:
>> Hi all,
>>
>> I'm currently working on a custom board with the imx6ull processor and the
>> 6390
>> switching chip. This is our hardware setup.
>>
>> ------------ --------- --------- MAC ------------
>> | i.MX | MAC | PHY | PHY | PHY |------------| 88E6390 |
>> | 6ULL |-----|KSZ8081|---------|LAN8742| MDIO |P0 |
>> | | |ID 0x1 | | ID0x0 |------------| |
>> | | --------- --------- | |
>> | | | |MULTI CHIP|
>> | | |MDIO |ADDR MODE |
>> | | | | |
>> | |--------------------------------------------| PHY ID |
>> | | MDIO | 0x2 |
>> ------------ ------------
> Hi Benjamin
>
> KSZ8081 is a 10/100 PHY, i think.
> LAN8742 is also a 10/100 PHY.
>
> However, DSA will configure the CPU port MAC to its maximum speed. So
> port 0 will be doing 1G. I don't know if specifying phy-mode = "rmii"
> is enough. You should take a look at the port status and configuration
> registers, see if the MAC is being forced to 1G, or 100M.
>
> You could add a fixed-phy to port 0 with speed 100. That will at least
> get the MAC part configured correctly.
>
> Is the LAN8742 strapped so that on power on it will auto-neg? I've
> seen a few board with this back-to-back PHY setup, and they just rely
> on the PHYs doing the right thing on power up, no software involved.
>
> Andrew
Good morning Andrew,
thanks for your reply. You're right, both PHYs are 10/100.
I already added a fixed-link like this:
port@0 {
reg = <0>;
label = "cpu";
ethernet = <&fec1>;
phy-mode = "rmii";
phy-handle = <&switch0phy0>;
fixed-link {
speed = <100>;
full-duplex;
};
};
I hope you mean that with fixed-phy? But this doesn't changed anything.
I would like to look at the port registers, but how can I read it when DSA
is started? When I delete the whole DSA part from the devicetree I found the
switch in multi chip addressing mode and can read the registers per indirect
reads from PHY ID 0x2. But when DSA is initialized our MII tool(which tool
could I use for that? ethtool?) gives back some odd values. Of course, I
would like to read it when DSA is running.
We will check the strapping again, because we have a strange behavior. On
some boots the external MDIO found a PHY at PHY ID 0x0 and on some it found
nothing.
Thanks,
Benjamin
