6.12-stable review patch. If anyone has any objections, please let me know.
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From: Raju Rangoju Raju.Rangoju@amd.com
[ Upstream commit 16ceda2ef683a50cd0783006c0504e1931cd8879 ]
The link status is latched low so that momentary link drops can be detected. Always double-reading the status defeats this design feature. Only double read if link was already down
This prevents unnecessary duplicate readings of the link status.
Fixes: 4f3b20bfbb75 ("amd-xgbe: add support for rx-adaptation") Signed-off-by: Raju Rangoju Raju.Rangoju@amd.com Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/20250701065016.4140707-1-Raju.Rangoju@amd.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/amd/xgbe/xgbe-mdio.c | 4 ++++ drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c | 24 +++++++++++++-------- 2 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c index 3316c719f9f8c..ed76a8df6ec6e 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c @@ -1413,6 +1413,10 @@ static void xgbe_phy_status(struct xgbe_prv_data *pdata)
pdata->phy.link = pdata->phy_if.phy_impl.link_status(pdata, &an_restart); + /* bail out if the link status register read fails */ + if (pdata->phy.link < 0) + return; + if (an_restart) { xgbe_phy_config_aneg(pdata); goto adjust_link; diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c index 268399dfcf22f..32e633d113484 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c @@ -2855,8 +2855,7 @@ static bool xgbe_phy_valid_speed(struct xgbe_prv_data *pdata, int speed) static int xgbe_phy_link_status(struct xgbe_prv_data *pdata, int *an_restart) { struct xgbe_phy_data *phy_data = pdata->phy_data; - unsigned int reg; - int ret; + int reg, ret;
*an_restart = 0;
@@ -2890,11 +2889,20 @@ static int xgbe_phy_link_status(struct xgbe_prv_data *pdata, int *an_restart) return 0; }
- /* Link status is latched low, so read once to clear - * and then read again to get current state - */ - reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); + if (reg < 0) + return reg; + + /* Link status is latched low so that momentary link drops + * can be detected. If link was already down read again + * to get the latest state. + */ + + if (!pdata->phy.link && !(reg & MDIO_STAT1_LSTATUS)) { + reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); + if (reg < 0) + return reg; + }
if (pdata->en_rx_adap) { /* if the link is available and adaptation is done, @@ -2913,9 +2921,7 @@ static int xgbe_phy_link_status(struct xgbe_prv_data *pdata, int *an_restart) xgbe_phy_set_mode(pdata, phy_data->cur_mode); }
- /* check again for the link and adaptation status */ - reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1); - if ((reg & MDIO_STAT1_LSTATUS) && pdata->rx_adapt_done) + if (pdata->rx_adapt_done) return 1; } else if (reg & MDIO_STAT1_LSTATUS) return 1;