[dpdk-dev] [PATCH] net/bnxt: fix PAM4 link negotiation

[Ajit Khaparde <ajit.khaparde@broadcom.com>]

In some instances link was not coming up if PAM4 signaling is enabled.
Added check to disable autoneg if FW indicates auto speeds are zero.
Use default auto speeds if PAM4 auto speeds is not set.
Added a fix for forced link setting.

Fixes: c23f9ded0391 ("net/bnxt: support 200G PAM4 link")

Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
---
 drivers/net/bnxt/bnxt_ethdev.c |  4 ++++
 drivers/net/bnxt/bnxt_hwrm.c   | 22 ++++++++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_ethdev.c b/drivers/net/bnxt/bnxt_ethdev.c
index 21ea370bf5..70edf824bc 100644
--- a/drivers/net/bnxt/bnxt_ethdev.c
+++ b/drivers/net/bnxt/bnxt_ethdev.c
@@ -845,6 +845,10 @@ uint32_t bnxt_get_speed_capabilities(struct bnxt *bp)
 	uint32_t link_speed = bp->link_info->support_speeds;
 	uint32_t speed_capa = 0;
 
+	/* If PAM4 is configured, use PAM4 supported speed */
+	if (link_speed == 0 && bp->link_info->support_pam4_speeds > 0)
+		link_speed = bp->link_info->support_pam4_speeds;
+
 	if (link_speed & HWRM_PORT_PHY_QCFG_OUTPUT_LINK_SPEED_100MB)
 		speed_capa |= ETH_LINK_SPEED_100M;
 	if (link_speed & HWRM_PORT_PHY_QCFG_OUTPUT_SUPPORT_SPEEDS_100MBHD)
diff --git a/drivers/net/bnxt/bnxt_hwrm.c b/drivers/net/bnxt/bnxt_hwrm.c
index 84702125cc..24c33185b4 100644
--- a/drivers/net/bnxt/bnxt_hwrm.c
+++ b/drivers/net/bnxt/bnxt_hwrm.c
@@ -1272,9 +1272,10 @@ static int bnxt_hwrm_port_phy_cfg(struct bnxt *bp, struct bnxt_link_info *conf)
 				HWRM_PORT_PHY_CFG_IN_EN_FORCE_PAM4_LINK_SPEED;
 				req.force_pam4_link_speed =
 					rte_cpu_to_le_16(conf->link_speed);
-			}
-			req.force_link_speed =
+			} else {
+				req.force_link_speed =
 					rte_cpu_to_le_16(conf->link_speed);
+			}
 		}
 		/* AutoNeg - Advertise speeds specified. */
 		if (conf->auto_link_speed_mask &&
@@ -1370,6 +1371,11 @@ static int bnxt_hwrm_port_phy_qcfg(struct bnxt *bp,
 		    link_info->link_speed, link_info->auto_mode,
 		    link_info->auto_link_speed, link_info->auto_link_speed_mask,
 		    link_info->support_speeds, link_info->force_link_speed);
+	PMD_DRV_LOG(DEBUG, "Link Signal:%d,PAM::Auto:%x,Support:%x,Force:%x\n",
+		    link_info->link_signal_mode,
+		    link_info->auto_pam4_link_speeds,
+		    link_info->support_pam4_speeds,
+		    link_info->force_pam4_link_speed);
 	return rc;
 }
 
@@ -3071,6 +3077,12 @@ int bnxt_set_hwrm_link_config(struct bnxt *bp, bool link_up)
 		autoneg = 0;
 	}
 
+	/* No auto speeds and no auto_pam4_link. Disable autoneg */
+	if (bp->link_info->auto_link_speed == 0 &&
+	    bp->link_info->link_signal_mode &&
+	    bp->link_info->auto_pam4_link_speeds == 0)
+		autoneg = 0;
+
 	speed = bnxt_parse_eth_link_speed(dev_conf->link_speeds,
 					  bp->link_info->link_signal_mode);
 	link_req.phy_flags = HWRM_PORT_PHY_CFG_INPUT_FLAGS_RESET_PHY;
@@ -3116,6 +3128,12 @@ int bnxt_set_hwrm_link_config(struct bnxt *bp, bool link_up)
 			link_req.link_speed = bp->link_info->force_link_speed;
 		else
 			link_req.link_speed = bp->link_info->auto_link_speed;
+		/* Auto PAM4 link speed is zero, but auto_link_speed is not
+		 * zero. Use the auto_link_speed.
+		 */
+		if (bp->link_info->auto_link_speed != 0 &&
+		    bp->link_info->auto_pam4_link_speeds == 0)
+			link_req.link_speed = bp->link_info->auto_link_speed;
 	}
 	link_req.duplex = bnxt_parse_eth_link_duplex(dev_conf->link_speeds);
 	link_req.auto_pause = bp->link_info->auto_pause;
-- 
2.21.1 (Apple Git-122.3)