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amd-xgbe: do not double read link status

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[ 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: 4f3b20bfbb ("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>
This commit is contained in:
Raju Rangoju
2025-07-01 12:20:16 +05:30
committed by Greg Kroah-Hartman
parent f680a4643c
commit 70b32cba5c
2 changed files with 19 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
View File

@@ -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;

24
drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
View File

@@ -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);
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.
*/
reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1);
reg = XMDIO_READ(pdata, MDIO_MMD_PCS, MDIO_STAT1);
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;