The initial MDIO read or write towards the BCM7xxx integrated PHY may
fail, workaround this by inserting a dummy MII_BMSR read to force the
MDIO management controller to see at least one valid transaction and get
out of stuck state out of reset.
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
drivers/net/phy/bcm7xxx.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/net/phy/bcm7xxx.c b/drivers/net/phy/bcm7xxx.c
index 4dea85bfc545..6b701b3ded74 100644
--- a/drivers/net/phy/bcm7xxx.c
+++ b/drivers/net/phy/bcm7xxx.c
@@ -246,6 +246,13 @@ static int bcm7xxx_28nm_config_init(struct phy_device
*phydev)
pr_info_once("%s: %s PHY revision: 0x%02x, patch: %d\n",
dev_name(&phydev->dev), phydev->drv->name, rev, patch);
+ /* Dummy read to a register to workaround an issue upon reset where the
+ * internal inverter may not allow the first MDIO transaction to pass
+ * the MDIO management controller and make us return 0xffff for such
+ * reads.
+ */
+ phy_read(phydev, MII_BMSR);
+
switch (rev) {
case 0xb0:
ret = bcm7xxx_28nm_b0_afe_config_init(phydev);
--
2.1.0
--
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