RE: [EXT] Re: [RESENT PATCH net--stat 1/1] net: ethernet: fec: Revert "net: ethernet: fec: Replace interrupt driven MDIO with polled IO"

[Andy Duan <fugang.duan@nxp.com>]

From: Chris Healy <cphealy@gmail.com> Sent: Monday, July 27, 2020 11:01 AM
> It appears quite a few boards were affected by this micrel PHY driver change:
> 
> 2ccb0161a0e9eb06f538557d38987e436fc39b8d
> 80bf72598663496d08b3c0231377db6a99d7fd68
> 2de00450c0126ec8838f72157577578e85cae5d8
> 820f8a870f6575acda1bf7f1a03c701c43ed5d79
> 
> I just updated the phy-mode with my board from rgmii to rgmii-id and
> everything started working fine with net-next again:
> 
> eth0      Link encap:Ethernet  HWaddr E6:85:48:8F:93:64
>           inet addr:172.16.1.1  Bcast:172.16.255.255  Mask:255.255.0.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:4643690 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:76178 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:2762845502 (2.5 GiB)  TX bytes:5026376 (4.7 MiB)
> 
> 

It is reasonable to change phy-mode to "rgmii-id" to let PHY supply
Tx/rx skew since MAC doesn't support delay.


Regards,
Fugang
> 
> On Sun, Jul 26, 2020 at 7:40 PM Chris Healy <cphealy@gmail.com> wrote:
> >
> > Actually, I was a little quick to say it went from broken to working.
> >
> > With net-next, I'm getting CRC errors on 100% of inbound packets.
> > With bcf3440c6dd78bfe5836ec0990fe36d7b4bb7d20 reverted, I drop down to
> > a 1% error rate.
> >
> > This very much feels like a KSZ9031 RGMII timing issue to me...
> >
> > On Sun, Jul 26, 2020 at 7:35 PM Chris Healy <cphealy@gmail.com> wrote:
> > >
> > > Hi Laurent,
> > >
> > > I have the exact same copper PHY.  I just reverted a patch specific
> > > to this PHY and went from broken to working.  Give this a try:
> > >
> > > git revert bcf3440c6dd78bfe5836ec0990fe36d7b4bb7d20
> > >
> > > Regards,
> > >
> > > Chris
> > >
> > > On Sun, Jul 26, 2020 at 7:33 PM Laurent Pinchart
> > > <laurent.pinchart@ideasonboard.com> wrote:
> > > >
> > > > Hi Andrew,
> > > >
> > > > On Mon, Jul 27, 2020 at 04:14:32AM +0200, Andrew Lunn wrote:
> > > > > On Mon, Jul 27, 2020 at 05:06:31AM +0300, Laurent Pinchart wrote:
> > > > > > On Mon, Jul 27, 2020 at 04:24:02AM +0300, Laurent Pinchart wrote:
> > > > > > > On Mon, Apr 27, 2020 at 10:08:04PM +0800, Fugang Duan wrote:
> > > > > > > > This reverts commit
> 29ae6bd1b0d8a57d7c00ab12cbb949fc41986eef.
> > > > > > > >
> > > > > > > > The commit breaks ethernet function on i.MX6SX, i.MX7D,
> > > > > > > > i.MX8MM, i.MX8MQ, and i.MX8QXP platforms. Boot yocto
> > > > > > > > system by NFS mounting rootfs will be failed with the commit.
> > > > > > >
> > > > > > > I'm afraid this commit breaks networking on i.MX7D for me
> > > > > > > :-( My board is configured to boot over NFS root with IP
> > > > > > > autoconfiguration through DHCP. The DHCP request goes out,
> > > > > > > the reply it sent back by the server, but never noticed by the fec
> driver.
> > > > > > >
> > > > > > > v5.7 works fine. As 29ae6bd1b0d8a57d7c00ab12cbb949fc41986eef
> > > > > > > was merged during the v5.8 merge window, I suspect something
> > > > > > > else cropped in between
> > > > > > > 29ae6bd1b0d8a57d7c00ab12cbb949fc41986eef and this patch that
> > > > > > > needs to be reverted too. We're close to v5.8 and it would
> > > > > > > be annoying to see this regression ending up in the released
> > > > > > > kernel. I can test patches, but I'm not familiar enough with
> > > > > > > the driver (or the networking
> > > > > > > subsystem) to fix the issue myself.
> > > > > >
> > > > > > If it can be of any help, I've confirmed that, to get the
> > > > > > network back to usable state from v5.8-rc6, I have to revert
> > > > > > all patches up to this one. This is the top of my branch, on top of
> v5.8-rc6:
> > > > > >
> > > > > > 5bbe80c9efea Revert "net: ethernet: fec: Revert "net: ethernet: fec:
> Replace interrupt driven MDIO with polled IO""
> > > > > > 5462896a08c1 Revert "net: ethernet: fec: Replace interrupt driven
> MDIO with polled IO"
> > > > > > 824a82e2bdfa Revert "net: ethernet: fec: move GPR register offset
> and bit into DT"
> > > > > > bfe330591cab Revert "net: fec: disable correct clk in the err path of
> fec_enet_clk_enable"
> > > > > > 109958cad578 Revert "net: ethernet: fec: prevent tx starvation under
> high rx load"
> > > > >
> > > > > OK.
> > > > >
> > > > > What PHY are you using? A Micrel?
> > > >
> > > > KSZ9031RNXIA
> > > >
> > > > > And which DT file?
> > > >
> > > > It's out of tree.
> > > >
> > > > &fec1 {
> > > >         pinctrl-names = "default";
> > > >         pinctrl-0 = <&pinctrl_enet1>;
> > > >         assigned-clocks = <&clks IMX7D_ENET1_TIME_ROOT_SRC>,
> > > >                           <&clks
> IMX7D_ENET1_TIME_ROOT_CLK>;
> > > >         assigned-clock-parents = <&clks
> IMX7D_PLL_ENET_MAIN_100M_CLK>;
> > > >         assigned-clock-rates = <0>, <100000000>;
> > > >         phy-mode = "rgmii";
> > > >         phy-handle = <&ethphy0>;
> > > >         phy-reset-gpios = <&gpio1 13 GPIO_ACTIVE_LOW>;
> > > >         phy-supply = <&reg_3v3_sw>;
> > > >         fsl,magic-packet;
> > > >         status = "okay";
> > > >
> > > >         mdio {
> > > >                 #address-cells = <1>;
> > > >                 #size-cells = <0>;
> > > >
> > > >                 ethphy0: ethernet-phy@0 {
> > > >                         reg = <1>;
> > > >                 };
> > > >
> > > >                 ethphy1: ethernet-phy@1 {
> > > >                         reg = <2>;
> > > >                 };
> > > >         };
> > > > };
> > > >
> > > > I can provide the full DT if needed.
> > > >
> > > > --
> > > > Regards,
> > > >
> > > > Laurent Pinchart