e1000e: Workaround for sporadic MDI error on Meteor Lake systems

[ Upstream commit 6dbdd4de0362c37e54e8b049781402e5a409e7d0 ]

On some Meteor Lake systems accessing the PHY via the MDIO interface may
result in an MDI error. This issue happens sporadically and in most cases
a second access to the PHY via the MDIO interface results in success.

As a workaround, introduce a retry counter which is set to 3 on Meteor
Lake systems. The driver will only return an error if 3 consecutive PHY
access attempts fail. The retry mechanism is disabled in specific flows,
where MDI errors are expected.

Fixes: cc23f4f0b6b9 ("e1000e: Add support for Meteor Lake")
Suggested-by: Nikolay Mushayev <nikolay.mushayev@intel.com>
Co-developed-by: Nir Efrati <nir.efrati@intel.com>
Signed-off-by: Nir Efrati <nir.efrati@intel.com>
Signed-off-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

4 files changed, 150 insertions, 69 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/hw.h b/drivers/net/ethernet/intel/e1000e/hw.h
index 1fef6bb5a5fb..4b6e7536170a 100644
--- a/drivers/net/ethernet/intel/e1000e/hw.h
+++ b/drivers/net/ethernet/intel/e1000e/hw.h
@@ -628,6 +628,7 @@ struct e1000_phy_info {
 	u32 id;
 	u32 reset_delay_us;	/* in usec */
 	u32 revision;
+	u32 retry_count;
 
 	enum e1000_media_type media_type;
 
@@ -644,6 +645,7 @@ struct e1000_phy_info {
 	bool polarity_correction;
 	bool speed_downgraded;
 	bool autoneg_wait_to_complete;
+	bool retry_enabled;
 };
 
 struct e1000_nvm_info {
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index a2788fd5f8bb..717c52913e84 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -222,11 +222,18 @@ out:
 	if (hw->mac.type >= e1000_pch_lpt) {
 		/* Only unforce SMBus if ME is not active */
 		if (!(er32(FWSM) & E1000_ICH_FWSM_FW_VALID)) {
+			/* Switching PHY interface always returns MDI error
+			 * so disable retry mechanism to avoid wasting time
+			 */
+			e1000e_disable_phy_retry(hw);
+
 			/* Unforce SMBus mode in PHY */
 			e1e_rphy_locked(hw, CV_SMB_CTRL, &phy_reg);
 			phy_reg &= ~CV_SMB_CTRL_FORCE_SMBUS;
 			e1e_wphy_locked(hw, CV_SMB_CTRL, phy_reg);
 
+			e1000e_enable_phy_retry(hw);
+
 			/* Unforce SMBus mode in MAC */
 			mac_reg = er32(CTRL_EXT);
 			mac_reg &= ~E1000_CTRL_EXT_FORCE_SMBUS;
@@ -310,6 +317,11 @@ static s32 e1000_init_phy_workarounds_pchlan(struct e1000_hw *hw)
 		goto out;
 	}
 
+	/* There is no guarantee that the PHY is accessible at this time
+	 * so disable retry mechanism to avoid wasting time
+	 */
+	e1000e_disable_phy_retry(hw);
+
 	/* The MAC-PHY interconnect may be in SMBus mode.  If the PHY is
 	 * inaccessible and resetting the PHY is not blocked, toggle the
 	 * LANPHYPC Value bit to force the interconnect to PCIe mode.
@@ -380,6 +392,8 @@ static s32 e1000_init_phy_workarounds_pchlan(struct e1000_hw *hw)
 		break;
 	}
 
+	e1000e_enable_phy_retry(hw);
+
 	hw->phy.ops.release(hw);
 	if (!ret_val) {
 
@@ -449,6 +463,11 @@ static s32 e1000_init_phy_params_pchlan(struct e1000_hw *hw)
 
 	phy->id = e1000_phy_unknown;
 
+	if (hw->mac.type == e1000_pch_mtp) {
+		phy->retry_count = 2;
+		e1000e_enable_phy_retry(hw);
+	}
+
 	ret_val = e1000_init_phy_workarounds_pchlan(hw);
 	if (ret_val)
 		return ret_val;
@@ -1146,6 +1165,11 @@ s32 e1000_enable_ulp_lpt_lp(struct e1000_hw *hw, bool to_sx)
 	if (ret_val)
 		goto out;
 
+	/* Switching PHY interface always returns MDI error
+	 * so disable retry mechanism to avoid wasting time
+	 */
+	e1000e_disable_phy_retry(hw);
+
 	/* Force SMBus mode in PHY */
 	ret_val = e1000_read_phy_reg_hv_locked(hw, CV_SMB_CTRL, &phy_reg);
 	if (ret_val)
@@ -1153,6 +1177,8 @@ s32 e1000_enable_ulp_lpt_lp(struct e1000_hw *hw, bool to_sx)
 	phy_reg |= CV_SMB_CTRL_FORCE_SMBUS;
 	e1000_write_phy_reg_hv_locked(hw, CV_SMB_CTRL, phy_reg);
 
+	e1000e_enable_phy_retry(hw);
+
 	/* Force SMBus mode in MAC */
 	mac_reg = er32(CTRL_EXT);
 	mac_reg |= E1000_CTRL_EXT_FORCE_SMBUS;
@@ -1313,6 +1339,11 @@ static s32 e1000_disable_ulp_lpt_lp(struct e1000_hw *hw, bool force)
 		/* Toggle LANPHYPC Value bit */
 		e1000_toggle_lanphypc_pch_lpt(hw);
 
+	/* Switching PHY interface always returns MDI error
+	 * so disable retry mechanism to avoid wasting time
+	 */
+	e1000e_disable_phy_retry(hw);
+
 	/* Unforce SMBus mode in PHY */
 	ret_val = e1000_read_phy_reg_hv_locked(hw, CV_SMB_CTRL, &phy_reg);
 	if (ret_val) {
@@ -1333,6 +1364,8 @@ static s32 e1000_disable_ulp_lpt_lp(struct e1000_hw *hw, bool force)
 	phy_reg &= ~CV_SMB_CTRL_FORCE_SMBUS;
 	e1000_write_phy_reg_hv_locked(hw, CV_SMB_CTRL, phy_reg);
 
+	e1000e_enable_phy_retry(hw);
+
 	/* Unforce SMBus mode in MAC */
 	mac_reg = er32(CTRL_EXT);
 	mac_reg &= ~E1000_CTRL_EXT_FORCE_SMBUS;
diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index 96ff0ca561b6..395746bcf8f7 100644
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -107,6 +107,16 @@ s32 e1000e_phy_reset_dsp(struct e1000_hw *hw)
 	return e1e_wphy(hw, M88E1000_PHY_GEN_CONTROL, 0);
 }
 
+void e1000e_disable_phy_retry(struct e1000_hw *hw)
+{
+	hw->phy.retry_enabled = false;
+}
+
+void e1000e_enable_phy_retry(struct e1000_hw *hw)
+{
+	hw->phy.retry_enabled = true;
+}
+
 /**
  *  e1000e_read_phy_reg_mdic - Read MDI control register
  *  @hw: pointer to the HW structure
@@ -118,55 +128,73 @@ s32 e1000e_phy_reset_dsp(struct e1000_hw *hw)
  **/
 s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data)
 {
+	u32 i, mdic = 0, retry_counter, retry_max;
 	struct e1000_phy_info *phy = &hw->phy;
-	u32 i, mdic = 0;
+	bool success;
 
 	if (offset > MAX_PHY_REG_ADDRESS) {
 		e_dbg("PHY Address %d is out of range\n", offset);
 		return -E1000_ERR_PARAM;
 	}
 
+	retry_max = phy->retry_enabled ? phy->retry_count : 0;
+
 	/* Set up Op-code, Phy Address, and register offset in the MDI
 	 * Control register.  The MAC will take care of interfacing with the
 	 * PHY to retrieve the desired data.
 	 */
-	mdic = ((offset << E1000_MDIC_REG_SHIFT) |
-		(phy->addr << E1000_MDIC_PHY_SHIFT) |
-		(E1000_MDIC_OP_READ));
+	for (retry_counter = 0; retry_counter <= retry_max; retry_counter++) {
+		success = true;
 
-	ew32(MDIC, mdic);
+		mdic = ((offset << E1000_MDIC_REG_SHIFT) |
+			(phy->addr << E1000_MDIC_PHY_SHIFT) |
+			(E1000_MDIC_OP_READ));
 
-	/* Poll the ready bit to see if the MDI read completed
-	 * Increasing the time out as testing showed failures with
-	 * the lower time out
-	 */
-	for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
-		udelay(50);
-		mdic = er32(MDIC);
-		if (mdic & E1000_MDIC_READY)
-			break;
-	}
-	if (!(mdic & E1000_MDIC_READY)) {
-		e_dbg("MDI Read PHY Reg Address %d did not complete\n", offset);
-		return -E1000_ERR_PHY;
-	}
-	if (mdic & E1000_MDIC_ERROR) {
-		e_dbg("MDI Read PHY Reg Address %d Error\n", offset);
-		return -E1000_ERR_PHY;
-	}
-	if (FIELD_GET(E1000_MDIC_REG_MASK, mdic) != offset) {
-		e_dbg("MDI Read offset error - requested %d, returned %d\n",
-		      offset, FIELD_GET(E1000_MDIC_REG_MASK, mdic));
-		return -E1000_ERR_PHY;
+		ew32(MDIC, mdic);
+
+		/* Poll the ready bit to see if the MDI read completed
+		 * Increasing the time out as testing showed failures with
+		 * the lower time out
+		 */
+		for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
+			usleep_range(50, 60);
+			mdic = er32(MDIC);
+			if (mdic & E1000_MDIC_READY)
+				break;
+		}
+		if (!(mdic & E1000_MDIC_READY)) {
+			e_dbg("MDI Read PHY Reg Address %d did not complete\n",
+			      offset);
+			success = false;
+		}
+		if (mdic & E1000_MDIC_ERROR) {
+			e_dbg("MDI Read PHY Reg Address %d Error\n", offset);
+			success = false;
+		}
+		if (FIELD_GET(E1000_MDIC_REG_MASK, mdic) != offset) {
+			e_dbg("MDI Read offset error - requested %d, returned %d\n",
+			      offset, FIELD_GET(E1000_MDIC_REG_MASK, mdic));
+			success = false;
+		}
+
+		/* Allow some time after each MDIC transaction to avoid
+		 * reading duplicate data in the next MDIC transaction.
+		 */
+		if (hw->mac.type == e1000_pch2lan)
+			usleep_range(100, 150);
+
+		if (success) {
+			*data = (u16)mdic;
+			return 0;
+		}
+
+		if (retry_counter != retry_max) {
+			e_dbg("Perform retry on PHY transaction...\n");
+			mdelay(10);
+		}
 	}
-	*data = (u16)mdic;
 
-	/* Allow some time after each MDIC transaction to avoid
-	 * reading duplicate data in the next MDIC transaction.
-	 */
-	if (hw->mac.type == e1000_pch2lan)
-		udelay(100);
-	return 0;
+	return -E1000_ERR_PHY;
 }
 
 /**
@@ -179,56 +207,72 @@ s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data)
  **/
 s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
 {
+	u32 i, mdic = 0, retry_counter, retry_max;
 	struct e1000_phy_info *phy = &hw->phy;
-	u32 i, mdic = 0;
+	bool success;
 
 	if (offset > MAX_PHY_REG_ADDRESS) {
 		e_dbg("PHY Address %d is out of range\n", offset);
 		return -E1000_ERR_PARAM;
 	}
 
+	retry_max = phy->retry_enabled ? phy->retry_count : 0;
+
 	/* Set up Op-code, Phy Address, and register offset in the MDI
 	 * Control register.  The MAC will take care of interfacing with the
 	 * PHY to retrieve the desired data.
 	 */
-	mdic = (((u32)data) |
-		(offset << E1000_MDIC_REG_SHIFT) |
-		(phy->addr << E1000_MDIC_PHY_SHIFT) |
-		(E1000_MDIC_OP_WRITE));
+	for (retry_counter = 0; retry_counter <= retry_max; retry_counter++) {
+		success = true;
 
-	ew32(MDIC, mdic);
+		mdic = (((u32)data) |
+			(offset << E1000_MDIC_REG_SHIFT) |
+			(phy->addr << E1000_MDIC_PHY_SHIFT) |
+			(E1000_MDIC_OP_WRITE));
 
-	/* Poll the ready bit to see if the MDI read completed
-	 * Increasing the time out as testing showed failures with
-	 * the lower time out
-	 */
-	for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
-		udelay(50);
-		mdic = er32(MDIC);
-		if (mdic & E1000_MDIC_READY)
-			break;
-	}
-	if (!(mdic & E1000_MDIC_READY)) {
-		e_dbg("MDI Write PHY Reg Address %d did not complete\n", offset);
-		return -E1000_ERR_PHY;
-	}
-	if (mdic & E1000_MDIC_ERROR) {
-		e_dbg("MDI Write PHY Red Address %d Error\n", offset);
-		return -E1000_ERR_PHY;
-	}
-	if (FIELD_GET(E1000_MDIC_REG_MASK, mdic) != offset) {
-		e_dbg("MDI Write offset error - requested %d, returned %d\n",
-		      offset, FIELD_GET(E1000_MDIC_REG_MASK, mdic));
-		return -E1000_ERR_PHY;
-	}
+		ew32(MDIC, mdic);
 
-	/* Allow some time after each MDIC transaction to avoid
-	 * reading duplicate data in the next MDIC transaction.
-	 */
-	if (hw->mac.type == e1000_pch2lan)
-		udelay(100);
+		/* Poll the ready bit to see if the MDI read completed
+		 * Increasing the time out as testing showed failures with
+		 * the lower time out
+		 */
+		for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
+			usleep_range(50, 60);
+			mdic = er32(MDIC);
+			if (mdic & E1000_MDIC_READY)
+				break;
+		}
+		if (!(mdic & E1000_MDIC_READY)) {
+			e_dbg("MDI Write PHY Reg Address %d did not complete\n",
+			      offset);
+			success = false;
+		}
+		if (mdic & E1000_MDIC_ERROR) {
+			e_dbg("MDI Write PHY Reg Address %d Error\n", offset);
+			success = false;
+		}
+		if (FIELD_GET(E1000_MDIC_REG_MASK, mdic) != offset) {
+			e_dbg("MDI Write offset error - requested %d, returned %d\n",
+			      offset, FIELD_GET(E1000_MDIC_REG_MASK, mdic));
+			success = false;
+		}
 
-	return 0;
+		/* Allow some time after each MDIC transaction to avoid
+		 * reading duplicate data in the next MDIC transaction.
+		 */
+		if (hw->mac.type == e1000_pch2lan)
+			usleep_range(100, 150);
+
+		if (success)
+			return 0;
+
+		if (retry_counter != retry_max) {
+			e_dbg("Perform retry on PHY transaction...\n");
+			mdelay(10);
+		}
+	}
+
+	return -E1000_ERR_PHY;
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/e1000e/phy.h b/drivers/net/ethernet/intel/e1000e/phy.h
index c48777d09523..049bb325b4b1 100644
--- a/drivers/net/ethernet/intel/e1000e/phy.h
+++ b/drivers/net/ethernet/intel/e1000e/phy.h
@@ -51,6 +51,8 @@ s32 e1000e_read_phy_reg_bm2(struct e1000_hw *hw, u32 offset, u16 *data);
 s32 e1000e_write_phy_reg_bm2(struct e1000_hw *hw, u32 offset, u16 data);
 void e1000_power_up_phy_copper(struct e1000_hw *hw);
 void e1000_power_down_phy_copper(struct e1000_hw *hw);
+void e1000e_disable_phy_retry(struct e1000_hw *hw);
+void e1000e_enable_phy_retry(struct e1000_hw *hw);
 s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data);
 s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data);
 s32 e1000_read_phy_reg_hv(struct e1000_hw *hw, u32 offset, u16 *data);