bnxt_en: Skip MAC loopback selftest if it is unsupported by FW

Call the new HWRM_PORT_MAC_QCAPS to check if mac loopback is
supported.  Skip the MAC loopback ethtool self test if it is
not supported.

Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://patch.msgid.link/20241217182620.2454075-5-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Michael Chan

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -11551,6 +11551,26 @@ static int bnxt_hwrm_phy_qcaps(struct bnxt *bp)
 	return rc;
 }
 
+static void bnxt_hwrm_mac_qcaps(struct bnxt *bp)
+{
+	struct hwrm_port_mac_qcaps_output *resp;
+	struct hwrm_port_mac_qcaps_input *req;
+	int rc;
+
+	if (bp->hwrm_spec_code < 0x10a03)
+		return;
+
+	rc = hwrm_req_init(bp, req, HWRM_PORT_MAC_QCAPS);
+	if (rc)
+		return;
+
+	resp = hwrm_req_hold(bp, req);
+	rc = hwrm_req_send_silent(bp, req);
+	if (!rc)
+		bp->mac_flags = resp->flags;
+	hwrm_req_drop(bp, req);
+}
+
 static bool bnxt_support_dropped(u16 advertising, u16 supported)
 {
 	u16 diff = advertising ^ supported;
@@ -15679,6 +15699,10 @@ static int bnxt_probe_phy(struct bnxt *bp, bool fw_dflt)
 		bp->dev->priv_flags |= IFF_SUPP_NOFCS;
 	else
 		bp->dev->priv_flags &= ~IFF_SUPP_NOFCS;
+
+	bp->mac_flags = 0;
+	bnxt_hwrm_mac_qcaps(bp);
+
 	if (!fw_dflt)
 		return 0;
 

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -2668,6 +2668,11 @@ struct bnxt {
 #define BNXT_PHY_FL_BANK_SEL		(PORT_PHY_QCAPS_RESP_FLAGS2_BANK_ADDR_SUPPORTED << 8)
 #define BNXT_PHY_FL_SPEEDS2		(PORT_PHY_QCAPS_RESP_FLAGS2_SPEEDS2_SUPPORTED << 8)
 
+	/* copied from flags in hwrm_port_mac_qcaps_output */
+	u8			mac_flags;
+#define BNXT_MAC_FL_NO_MAC_LPBK		\
+	PORT_MAC_QCAPS_RESP_FLAGS_LOCAL_LPBK_NOT_SUPPORTED
+
 	u8			num_tests;
 	struct bnxt_test_info	*test_info;
 

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -4899,21 +4899,24 @@ static void bnxt_self_test(struct net_device *dev, struct ethtool_test *etest,
 		bnxt_close_nic(bp, true, false);
 		bnxt_run_fw_tests(bp, test_mask, &test_results);
 
-		buf[BNXT_MACLPBK_TEST_IDX] = 1;
-		bnxt_hwrm_mac_loopback(bp, true);
-		msleep(250);
 		rc = bnxt_half_open_nic(bp);
 		if (rc) {
-			bnxt_hwrm_mac_loopback(bp, false);
 			etest->flags |= ETH_TEST_FL_FAILED;
 			return;
 		}
+		buf[BNXT_MACLPBK_TEST_IDX] = 1;
+		if (bp->mac_flags & BNXT_MAC_FL_NO_MAC_LPBK)
+			goto skip_mac_loopback;
+
+		bnxt_hwrm_mac_loopback(bp, true);
+		msleep(250);
 		if (bnxt_run_loopback(bp))
 			etest->flags |= ETH_TEST_FL_FAILED;
 		else
 			buf[BNXT_MACLPBK_TEST_IDX] = 0;
 
 		bnxt_hwrm_mac_loopback(bp, false);
+skip_mac_loopback:
 		buf[BNXT_PHYLPBK_TEST_IDX] = 1;
 		if (bp->phy_flags & BNXT_PHY_FL_NO_PHY_LPBK)
 			goto skip_phy_loopback;