From 1a3f4e83bc37c2eee13b4efdeb09209108fd673b Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 10 Jun 2015 12:24:11 -0700 Subject: [PATCH] net: phy: mdio-bcm-unimac: handle broken turn-around for specific PHYs Some Ethernet PHYs/switches such as Broadcom's BCM53125 have a hardware bug which makes them not release the MDIO line during turn-around time. This gets flagged by the UniMAC MDIO controller as a read failure, and we fail the read transaction. Check the MDIO bus phy_ignore_ta_mask bitmask for the PHY we are reading from and if it is listed in this bitmask, ignore the read failure and proceed with returning the data we read out of the controller. Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/phy/mdio-bcm-unimac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/phy/mdio-bcm-unimac.c b/drivers/net/phy/mdio-bcm-unimac.c index 414fdf1f343f..fc7abc50b4f1 100644 --- a/drivers/net/phy/mdio-bcm-unimac.c +++ b/drivers/net/phy/mdio-bcm-unimac.c @@ -81,7 +81,13 @@ static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg) return -ETIMEDOUT; cmd = __raw_readl(priv->base + MDIO_CMD); - if (cmd & MDIO_READ_FAIL) + + /* Some broken devices are known not to release the line during + * turn-around, e.g: Broadcom BCM53125 external switches, so check for + * that condition here and ignore the MDIO controller read failure + * indication. + */ + if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (cmd & MDIO_READ_FAIL)) return -EIO; return cmd & 0xffff; -- 2.20.1