From: Dylan Hung dylan_hung@aspeedtech.com
commit 9dbe33cf371bd70330858370bdbc35c7668f00c3 upstream.
The issue happened randomly in runtime. The message "Link is Down" is popped but soon it recovered to "Link is Up".
The "Link is Down" results from the incorrect read data for reading the PHY register via MDIO bus. The correct sequence for reading the data shall be: 1. fire the command 2. wait for command done (this step was missing) 3. wait for data idle 4. read data from data register
Cc: stable@vger.kernel.org Fixes: f160e99462c6 ("net: phy: Add mdio-aspeed") Reviewed-by: Joel Stanley joel@jms.id.au Signed-off-by: Dylan Hung dylan_hung@aspeedtech.com Reviewed-by: Andrew Lunn andrew@lunn.ch Reviewed-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Link: https://lore.kernel.org/r/20211125024432.15809-1-dylan_hung@aspeedtech.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/mdio/mdio-aspeed.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/drivers/net/mdio/mdio-aspeed.c +++ b/drivers/net/mdio/mdio-aspeed.c @@ -61,6 +61,13 @@ static int aspeed_mdio_read(struct mii_b
iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
+ rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl, + !(ctrl & ASPEED_MDIO_CTRL_FIRE), + ASPEED_MDIO_INTERVAL_US, + ASPEED_MDIO_TIMEOUT_US); + if (rc < 0) + return rc; + rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data, data & ASPEED_MDIO_DATA_IDLE, ASPEED_MDIO_INTERVAL_US,