libphy: PHY stmmac-0:ffffffff not found

commit 88f8b1bb41c6208f81b6a480244533ded7b59493

Author: Gabriel Fernandez <[email protected]>
Date:   Mon Feb 29 17:18:22 2016 +0100

stmmac: Fix 'eth0: No PHY found' regression

This patch manages the case when you have an Ethernet MAC with a "fixed link", and not connected to a normal MDIO-managed PHY device.

The test of phy_bus_name was not helpful because it was never affected and replaced by the mdio test node.

caused a regression on the Banana Pi M1 board:
...

[    1.573419] sun7i-dwmac 1c50000.ethernet: no reset control found
[    1.583476]  Ring mode enabled
[    1.590476]  No HW DMA feature register supported
[    1.595153]  Normal descriptors
[    1.606075]  TX Checksum insertion supported
...
[    9.430047] libphy: PHY stmmac-0:ffffffff not found
[    9.441829] eth0: Could not attach to PHY
[    9.452743] stmmac_open: Cannot attach to PHY (error: -19)

Reverting this commit makes it work again:

[    1.574459] sun7i-dwmac 1c50000.ethernet: no reset control found
[    1.584501]  Ring mode enabled
[    1.591491]  No HW DMA feature register supported
[    1.596169]  Normal descriptors
[    1.607076]  TX Checksum insertion supported
[    1.615766] sun7i-dwmac 1c50000.ethernet eth0: No MDIO subnode found
[    1.629108] libphy: stmmac: probed
[    1.636267] eth0: PHY ID 001cc915 at 0 IRQ POLL (stmmac-0:00) active
[    1.646446] eth0: PHY ID 001cc915 at 1 IRQ POLL (stmmac-0:01)
...
[   10.086423]  RX IPC Checksum Offload disabled
[   10.097628]  No MAC Management Counters available
[   14.084839] sun7i-dwmac 1c50000.ethernet eth0: Link is Up -

100Mbps/Full - flow control rx/tx

Regards,
Frank Schäfer

Hi Frank

yes we are also looking at this problem in this thread:

[PATCH v3 0/8] arm64: rockchip: Initial GeekBox enablement

I am implementing a patch and I will propose it soon.

Peppe