On 7/30/19 7:34 PM, Andrew Lunn wrote: >> Hi Andrew, >> >> The BCM54616S PHY on my machine is connected to a BCM5396 switch chip over >> backplane (1000Base-KX). > > Ah, that is different. So the board is using it for RGMII to 1000Base-KX? > > phy-mode is about the MAC-PHY link. So in this case RGMII.
Yes. It's RGMII to 1000Base-KX. > There is no DT way to configure the PHY-Switch link. However, it > sounds like you have the PHY strapped so it is doing 1000BaseX on the > PHY-Switch link. So do you actually need to configure this? The PHY is strapped in RGMII-Fiber Mode (the term used in datasheet), but besides 1000BaseX, 100Base-FX is also supported in this mode. The datasheet doesn't say which link type (1000BaseX or 100Base-FX) is active after reset and I cannot find a way to auto-detect the link type, either. Below are a few more details about 1000Base-X and 100Base-FX in BCM54616S datasheet. - 1000BaseX: The 1000BaseX register set (MII registers 00-0F) needs to be enabled by setting bit 0 of Mode Control Register. Although the register address is the same between 1000BaseX and 1000BaseT/100BaseT/10BaseT registers, some bit fields in 1000BaseX registers are different: for example, speed field is not available in 1000BaseX status register. - 100Base-FX: 100Base-FX registers need to be enabled by writing 1 to SerDes 100FX Control Register. 100Base-FX Control and Status registers are in shadow register 1Ch, instead of MII register 00h and 01h. > You report you never see link up? So maybe the problem is actually in > read_status? When in 1000BaseX mode, do you need to read the link > status from some other register? The Marvell PHYs use a second page > for 1000BaseX. read_status callback needs to be updated to report correct link speed in my case. But as I cannot tell which link type (1000BaseX or 100Base-FX) is active, it becomes hard to access registers in read_status method. Any suggestions? BTW, link-never-up issue seems to be caused by static/dynamic feature detection. I'm still tracing down the issue and it's being tracked in patch #1 of the series. Thanks, Tao