On Jan 13 2021, Palmer Dabbelt wrote: > On Tue, 10 Nov 2020 07:22:09 PST (-0800), sagar.kadam@xxxxxxxxxx wrote: >> HiFive Unleashed is having VSC8541-01 ethernet phy device and requires a >> specific reset sequence of 0-1-0-1 in order to use it in unmanaged mode. >> This series addresses a corner case where phy reset is not handled by boot >> stages prior to linux. >> Somewhat similar unreliable phy probe failure was reported and discussed >> here [1]. >> The macb driver fails to detect the ethernet phy device if the bootloader >> doesn't provide a proper reset sequence to the phy device or the phy itself >> is in some invalid state. Currently, the FSBL or u-boot-spl is resetting >> the phy device, and so there is no issue observed in the linux network >> setup. >> >> The series is based on linux-5.10-rc5. >> Patch 1: Add the OUI to the phy dt node to fix issue of missing mdio device >> Patch 2 and 3: >> Resetting phy needs GPIO support so add to dt and defconfig. >> >> [1] https://lkml.org/lkml/2018/11/29/154 >> >> To reproduce the issue: >> Using FSBL: >> 1. Comment out VSC8541 reset sequence in fsbl/main.c >> from within the freedom-u540-c000-bootloader. >> 2. Build and flash fsbl.bin to micro sdcard. >> >> Using u-boot: >> 1. Comment out VSC8541 reset sequence in board/sifive/fu540/spl.c >> from mainline u-boot source code. >> 2. Build and flash u-boot binaries to micro sdcard. >> >> Boot the board and bootlog will show network setup failure messages as: >> >> [ 1.069474] libphy: MACB_mii_bus: probed >> [ 1.073092] mdio_bus 10090000.ethernet-ffffffff: MDIO device at address 0 >> is missing >> ..... >> [ 1.979252] macb 10090000.ethernet eth0: Could not attach PHY (-19) >> >> 3. Now apply the series build, and boot kernel. >> 4. MACB and VSC8541 driver get successfully probed and the network is set >> without any failure. >> >> >> So irrespective of whether the prior stages handle the phy reset sequence, >> the probing is successful in both the cases of cold boot and warm boot. >> >> Change History: >> =============================== >> V2: >> -Rebased v1 on linux kernel v5.10-rc3. >> >> V1: >> -Ignore 4th patch as suggested and so removed it from the series. >> -Verified this series on 5.7-rc5. >> >> V0: Base RFC patch. Verified on 5.7-rc2 >> >> Sagar Shrikant Kadam (3): >> dts: phy: fix missing mdio device and probe failure of vsc8541-01 >> device >> dts: phy: add GPIO number and active state used for phy reset >> riscv: defconfig: enable gpio support for HiFive Unleashed >> >> arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 2 ++ >> arch/riscv/configs/defconfig | 2 ++ >> 2 files changed, 4 insertions(+) > > David pointed out I missed these, they're on fixes. Thanks! This is now on 5.10.12, and breaks ethernet on the Hifive Unleashed: [ 12.777976] macb 10090000.ethernet: Registered clk switch 'sifive-gemgxl-mgmt' [ 12.784559] macb 10090000.ethernet: GEM doesn't support hardware ptp. [ 12.791629] libphy: MACB_mii_bus: probed [ 12.919728] MACsec IEEE 802.1AE [ 12.984676] macb 10090000.ethernet eth0: Cadence GEM rev 0x10070109 at 0x10090000 irq 16 (70:b3:d5:92:f1:07) [ 14.030319] Microsemi VSC8541 SyncE 10090000.ethernet-ffffffff:00: phy_poll_reset failed: -110 [ 14.038986] macb 10090000.ethernet eth0: Could not attach PHY (-110) Andreas. -- Andreas Schwab, schwab@xxxxxxxxxxxxxx GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
