e1000e: change usleep_range to udelay in PHY mdic access

This is a partial revert of commit 6dbdd4de0362 ("e1000e: Workaround
for sporadic MDI error on Meteor Lake systems"). The referenced commit
used usleep_range inside the PHY access routines, which are sometimes
called from an atomic context. This can lead to a kernel panic in some
scenarios, such as cable disconnection and reconnection on vPro systems.

Solve this by changing the usleep_range calls back to udelay.

Fixes: 6dbdd4de0362 ("e1000e: Workaround for sporadic MDI error on Meteor Lake systems")
Cc: stable@vger.kernel.org
Reported-by: Jérôme Carretero <cJ@zougloub.eu>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218740
Closes: https://lore.kernel.org/lkml/a7eb665c74b5efb5140e6979759ed243072cb24a.camel@zougloub.eu/
Co-developed-by: Sasha Neftin <sasha.neftin@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Signed-off-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
Tested-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240429171040.1152516-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index 93544f1..f7ae0e0 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -157,7 +157,7 @@ s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data)
                 * the lower time out
                 */
                for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
-                       usleep_range(50, 60);
+                       udelay(50);
                        mdic = er32(MDIC);
                        if (mdic & E1000_MDIC_READY)
                                break;
@@ -181,7 +181,7 @@ s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data)
                 * reading duplicate data in the next MDIC transaction.
                 */
                if (hw->mac.type == e1000_pch2lan)
-                       usleep_range(100, 150);
+                       udelay(100);
 
                if (success) {
                        *data = (u16)mdic;
@@ -237,7 +237,7 @@ s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
                 * the lower time out
                 */
                for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
-                       usleep_range(50, 60);
+                       udelay(50);
                        mdic = er32(MDIC);
                        if (mdic & E1000_MDIC_READY)
                                break;
@@ -261,7 +261,7 @@ s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
                 * reading duplicate data in the next MDIC transaction.
                 */
                if (hw->mac.type == e1000_pch2lan)
-                       usleep_range(100, 150);
+                       udelay(100);
 
                if (success)
                        return 0;