Hello, A gentle reminder. Any suggestions here? BR, Sagar > -----Original Message----- > From: Sagar Kadam <sagar.kadam@xxxxxxxxxx> > Sent: Wednesday, May 13, 2020 7:27 PM > To: linux-kernel@xxxxxxxxxxxxxxx; linux-riscv@xxxxxxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx > Cc: palmer@xxxxxxxxxxx; Paul Walmsley <paul.walmsley@xxxxxxxxxx>; > atish.patra@xxxxxxx; Sagar Kadam <sagar.kadam@xxxxxxxxxx> > Subject: [PATCH v1 0/3] fix macb phy probe failure if phy-reset is not > handled > > 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 is resetting the phy device, and > so there is no issue observed in the linux network setup. > > The series is based on linux-5.7-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: > 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. > > 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: > =============================== > 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(+) > > -- > 2.7.4
