Map the link_down_reason from the FW to the ethtool link_ext_state
when it is available.  Also log it to the link down dmesg when it is
available.

Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     | 27 ++++++++++++++++++-
 drivers/net/ethernet/broadcom/bnxt/bnxt.h     |  1 +
 .../net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 21 +++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 9efdc382ebd7..6104c23f1c55 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11906,6 +11906,28 @@ static char *bnxt_report_fec(struct bnxt_link_info *link_info)
 	}
 }
 
+static char *bnxt_link_down_reason(struct bnxt_link_info *link_info)
+{
+	u8 reason = link_info->link_down_reason;
+
+	/* Multiple bits can be set, we report 1 bit only in order of
+	 * priority.
+	 */
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_RF)
+		return "(Remote fault)";
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_OTP_SPEED_VIOLATION)
+		return "(OTP Speed limit violation)";
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_CABLE_REMOVED)
+		return "(Cable removed)";
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_MODULE_FAULT)
+		return "(Module fault)";
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_BMC_REQUEST)
+		return "(BMC request down)";
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_TX_LASER_DISABLED)
+		return "(TX laser disabled)";
+	return "";
+};
+
 void bnxt_report_link(struct bnxt *bp)
 {
 	if (BNXT_LINK_IS_UP(bp)) {
@@ -11963,8 +11985,10 @@ void bnxt_report_link(struct bnxt *bp)
 				    (fec & BNXT_FEC_AUTONEG) ? "on" : "off",
 				    bnxt_report_fec(&bp->link_info));
 	} else {
+		char *str = bnxt_link_down_reason(&bp->link_info);
+
 		netif_carrier_off(bp->dev);
-		netdev_err(bp->dev, "NIC Link is Down\n");
+		netdev_err(bp->dev, "NIC Link is Down %s\n", str);
 	}
 }
 
@@ -12164,6 +12188,7 @@ int bnxt_update_link(struct bnxt *bp, bool chng_link_state)
 	link_info->phy_addr = resp->eee_config_phy_addr &
 			      PORT_PHY_QCFG_RESP_PHY_ADDR_MASK;
 	link_info->module_status = resp->module_status;
+	link_info->link_down_reason = resp->link_down_reason;
 
 	if (bp->phy_flags & BNXT_PHY_FL_EEE_CAP) {
 		struct ethtool_keee *eee = &bp->eee;
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 476c5684a1eb..aff781f167d4 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -1555,6 +1555,7 @@ struct bnxt_link_info {
 #define BNXT_LINK_STATE_DOWN	1
 #define BNXT_LINK_STATE_UP	2
 #define BNXT_LINK_IS_UP(bp)	((bp)->link_info.link_state == BNXT_LINK_STATE_UP)
+	u8			link_down_reason;
 	u8			active_lanes;
 	u8			duplex;
 #define BNXT_LINK_DUPLEX_HALF	PORT_PHY_QCFG_RESP_DUPLEX_STATE_HALF
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index a5ed6dd42bfc..0c9a29bbfa41 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -3432,6 +3432,26 @@ static u32 bnxt_get_link(struct net_device *dev)
 	return BNXT_LINK_IS_UP(bp);
 }
 
+static int bnxt_get_link_ext_state(struct net_device *dev,
+				   struct ethtool_link_ext_state_info *info)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	u8 reason;
+
+	if (BNXT_LINK_IS_UP(bp))
+		return -ENODATA;
+
+	reason = bp->link_info.link_down_reason;
+	if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_CABLE_REMOVED) {
+		info->link_ext_state = ETHTOOL_LINK_EXT_STATE_NO_CABLE;
+		return 0;
+	} else if (reason & PORT_PHY_QCFG_RESP_LINK_DOWN_REASON_MODULE_FAULT) {
+		info->link_ext_state = ETHTOOL_LINK_EXT_STATE_MODULE;
+		return 0;
+	}
+	return -ENODATA;
+}
+
 int bnxt_hwrm_nvm_get_dev_info(struct bnxt *bp,
 			       struct hwrm_nvm_get_dev_info_output *nvm_dev_info)
 {
@@ -5711,6 +5731,7 @@ const struct ethtool_ops bnxt_ethtool_ops = {
 	.get_eeprom             = bnxt_get_eeprom,
 	.set_eeprom		= bnxt_set_eeprom,
 	.get_link		= bnxt_get_link,
+	.get_link_ext_state	= bnxt_get_link_ext_state,
 	.get_link_ext_stats	= bnxt_get_link_ext_stats,
 	.get_eee		= bnxt_get_eee,
 	.set_eee		= bnxt_set_eee,
-- 
2.51.0