ixgbe: Manual AN-37 for troublesome link partners for X550 SFI

Some (Juniper MX5) SFP link partners exhibit a disinclination to
autonegotiate with X550 configured in SFI mode.  This patch enables
a manual AN-37 restart to work around the problem.
Signed-off-by: Jeff Daly <jeffd@silicom-usa.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_type.h

@@ -3712,7 +3712,9 @@ struct ixgbe_info {
 #define IXGBE_KRM_LINK_S1(P)		((P) ? 0x8200 : 0x4200)
 #define IXGBE_KRM_LINK_CTRL_1(P)	((P) ? 0x820C : 0x420C)
 #define IXGBE_KRM_AN_CNTL_1(P)		((P) ? 0x822C : 0x422C)
+#define IXGBE_KRM_AN_CNTL_4(P)		((P) ? 0x8238 : 0x4238)
 #define IXGBE_KRM_AN_CNTL_8(P)		((P) ? 0x8248 : 0x4248)
+#define IXGBE_KRM_PCS_KX_AN(P)		((P) ? 0x9918 : 0x5918)
 #define IXGBE_KRM_SGMII_CTRL(P)		((P) ? 0x82A0 : 0x42A0)
 #define IXGBE_KRM_LP_BASE_PAGE_HIGH(P)	((P) ? 0x836C : 0x436C)
 #define IXGBE_KRM_DSP_TXFFE_STATE_4(P)	((P) ? 0x8634 : 0x4634)
@@ -3722,6 +3724,7 @@ struct ixgbe_info {
 #define IXGBE_KRM_PMD_FLX_MASK_ST20(P)	((P) ? 0x9054 : 0x5054)
 #define IXGBE_KRM_TX_COEFF_CTRL_1(P)	((P) ? 0x9520 : 0x5520)
 #define IXGBE_KRM_RX_ANA_CTL(P)		((P) ? 0x9A00 : 0x5A00)
+#define IXGBE_KRM_FLX_TMRS_CTRL_ST31(P)	((P) ? 0x9180 : 0x5180)
 
 #define IXGBE_KRM_PMD_FLX_MASK_ST20_SFI_10G_DA		~(0x3 << 20)
 #define IXGBE_KRM_PMD_FLX_MASK_ST20_SFI_10G_SR		BIT(20)

drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c

@@ -1721,10 +1721,60 @@ static s32 ixgbe_setup_sfi_x550a(struct ixgbe_hw *hw, ixgbe_link_speed *speed)
 		return IXGBE_ERR_LINK_SETUP;
 	}
 
-	status = mac->ops.write_iosf_sb_reg(hw,
+	(void)mac->ops.write_iosf_sb_reg(hw,
 			IXGBE_KRM_PMD_FLX_MASK_ST20(hw->bus.lan_id),
 			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
 
+	/* change mode enforcement rules to hybrid */
+	(void)mac->ops.read_iosf_sb_reg(hw,
+			IXGBE_KRM_FLX_TMRS_CTRL_ST31(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, &reg_val);
+	reg_val |= 0x0400;
+
+	(void)mac->ops.write_iosf_sb_reg(hw,
+			IXGBE_KRM_FLX_TMRS_CTRL_ST31(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
+
+	/* manually control the config */
+	(void)mac->ops.read_iosf_sb_reg(hw,
+			IXGBE_KRM_LINK_CTRL_1(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, &reg_val);
+	reg_val |= 0x20002240;
+
+	(void)mac->ops.write_iosf_sb_reg(hw,
+			IXGBE_KRM_LINK_CTRL_1(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
+
+	/* move the AN base page values */
+	(void)mac->ops.read_iosf_sb_reg(hw,
+			IXGBE_KRM_PCS_KX_AN(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, &reg_val);
+	reg_val |= 0x1;
+
+	(void)mac->ops.write_iosf_sb_reg(hw,
+			IXGBE_KRM_PCS_KX_AN(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
+
+	/* set the AN37 over CB mode */
+	(void)mac->ops.read_iosf_sb_reg(hw,
+			IXGBE_KRM_AN_CNTL_4(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, &reg_val);
+	reg_val |= 0x20000000;
+
+	(void)mac->ops.write_iosf_sb_reg(hw,
+			IXGBE_KRM_AN_CNTL_4(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
+
+	/* restart AN manually */
+	(void)mac->ops.read_iosf_sb_reg(hw,
+			IXGBE_KRM_LINK_CTRL_1(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, &reg_val);
+	reg_val |= IXGBE_KRM_LINK_CTRL_1_TETH_AN_RESTART;
+
+	(void)mac->ops.write_iosf_sb_reg(hw,
+			IXGBE_KRM_LINK_CTRL_1(hw->bus.lan_id),
+			IXGBE_SB_IOSF_TARGET_KR_PHY, reg_val);
+
 	/* Toggle port SW reset by AN reset. */
 	status = ixgbe_restart_an_internal_phy_x550em(hw);