Re: Xilinx axienet + DP83620 in fiber mode won't set netif_carrier_on
On Wed, May 16, 2018 at 03:11:34PM +0200, Andrew Lunn wrote: > Hi Alvaro > > What should happen in general terms is that at some point the link to > the peer is established. phylib, the generic PHY code, polls the PHY > ever second, asking what the link state is. When the link changes from > down to up, phylib will call the link_adjust callback in the MAC, and > netif_carrier_on(). > > When the PHY reports the link has gone down, it does similar, calls > the adjust_link callback, and netif_carrier_off(). > > So what you need to do is find out why the PHY driver never reports > link up. Does the PHY even know when the link is up? Often SFF/SFP > modules have a Signal Detect pin, which is connected to a gpio. Do you > have something like that? If so, you should look at the PHYLINK code > and the SFP device which was added recently. I didn't know about the SFP device. I don't think this will help my specific case because my board didn't route the i2c bus from the SFP, so it basically sits there and does it thing alone, I can't communicate with it. I see that net/phy/marvell.c has a custom marvell_update_link that reads a different register to check for fiber connectivity instead of using genphy_update_link, which I see reads from MII_BMSR.BMSR_LSTATUS It looks like the DP83620 may do something similar, and the fiber status may be accesible from some other register. This starts to make sense, thanks for setting my on track! Best regards! -- Alvaro G. M.
Re: Xilinx axienet + DP83620 in fiber mode won't set netif_carrier_on
On Wed, May 16, 2018 at 11:16:31AM +0200, Alvaro G. M. wrote: > Hi, > > I have a custom board with a Xilinx FPGA running Microblaze and fitting a > Xilinx Axi Ethernet IP core. This core communicates through MII mode with a > DP83620 PHY from Texas that supports both cabled and fiber interfaces, of > which I'm using the latter. > > Under these circumstances, I've noticed that the interface is pretty much > dead except for receiving broadcast packages, so I tried to dig on the > driver to find the cause. Please, beware that I'm not very familiar with the > netdev subsystem, so I may be mistaken on lots of things. > > It seems that of_phy_connect ends up calling netif_carrier_off: > > phy_device.c:1036 > /* Initial carrier state is off as the phy is about to be >* (re)initialized. >*/ > netif_carrier_off(phydev->attached_dev); > > /* Do initial configuration here, now that >* we have certain key parameters >* (dev_flags and interface) >*/ > err = phy_init_hw(phydev); > if (err) > goto error; > > phy_resume(phydev); > > However, neither xilinx_axienet_main.c nor dp83848.c ever runs > netif_carrier_on. Hi Alvaro What should happen in general terms is that at some point the link to the peer is established. phylib, the generic PHY code, polls the PHY ever second, asking what the link state is. When the link changes from down to up, phylib will call the link_adjust callback in the MAC, and netif_carrier_on(). When the PHY reports the link has gone down, it does similar, calls the adjust_link callback, and netif_carrier_off(). So what you need to do is find out why the PHY driver never reports link up. Does the PHY even know when the link is up? Often SFF/SFP modules have a Signal Detect pin, which is connected to a gpio. Do you have something like that? If so, you should look at the PHYLINK code and the SFP device which was added recently. Andrew
Xilinx axienet + DP83620 in fiber mode won't set netif_carrier_on
Hi, I have a custom board with a Xilinx FPGA running Microblaze and fitting a Xilinx Axi Ethernet IP core. This core communicates through MII mode with a DP83620 PHY from Texas that supports both cabled and fiber interfaces, of which I'm using the latter. Under these circumstances, I've noticed that the interface is pretty much dead except for receiving broadcast packages, so I tried to dig on the driver to find the cause. Please, beware that I'm not very familiar with the netdev subsystem, so I may be mistaken on lots of things. It seems that of_phy_connect ends up calling netif_carrier_off: phy_device.c:1036 /* Initial carrier state is off as the phy is about to be * (re)initialized. */ netif_carrier_off(phydev->attached_dev); /* Do initial configuration here, now that * we have certain key parameters * (dev_flags and interface) */ err = phy_init_hw(phydev); if (err) goto error; phy_resume(phydev); However, neither xilinx_axienet_main.c nor dp83848.c ever runs netif_carrier_on. As a simple test, I tried this patch, and that was enough to make the interface work. diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index e74e1e897864..d8bbe4c51b8a 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -957,6 +957,8 @@ static int axienet_open(struct net_device *ndev) if (ret) goto err_rx_irq; + netif_carrier_on(ndev); + return 0; err_rx_irq: I understand, however, that this is just a proof of concept that shows the underlying issue. I'd like to contribute to making this a proper patch, or maybe anyone who is familiar with the netdev subsystem knows at first sight what is the solution for this. My understanding is that this code works fine with other PHY chips, as pretty much the same code has been in the kernel for a long time, but that probably before ee06b1728b95643668e40fc58ae118aeb7c1753e (which I instigated) this Xilinx core and driver had never been tested with any interface other than GMII and RGMII, which were back then written explicitly, with an unknown PHY chip. I should also note that axienet_adjust_link is never called in this configuration, which is the place where I think the call to netif_carrier_on should be (based on what I've read on other ethernet drivers), but it seems that the dp83620 doesn't notify of any autonegotiation (at least while on fiber mode). I'm open to reading and testing whatever is needed, and please, feel free to correct me if I've said anything incorrect, which most probably I've done. Best regards -- Alvaro G. M.
