[PATCH 5.10 449/663] net: stmmac: fix CBS idleslope and sendslope calculation

[Greg Kroah-Hartman]

From: Song, Yoong Siang <yoong.siang.song@xxxxxxxxx>

[ Upstream commit 24877687b375f2c476ffb726ea915fc85df09e3d ]

When link speed is not 100 Mbps, port transmit rate and speed divider
are set to 8 and 1000000 respectively. These values are incorrect for
CBS idleslope and sendslope HW values calculation if the link speed is
not 1 Gbps.

This patch adds switch statement to set the values of port transmit rate
and speed divider for 10 Gbps, 5 Gbps, 2.5 Gbps, 1 Gbps, and 100 Mbps.
Note that CBS is not supported at 10 Mbps.

Fixes: bc41a6689b30 ("net: stmmac: tc: Remove the speed dependency")
Fixes: 1f705bc61aee ("net: stmmac: Add support for CBS QDISC")
Signed-off-by: Song, Yoong Siang <yoong.siang.song@xxxxxxxxx>
Link: https://lore.kernel.org/r/1613655653-11755-1-git-send-email-yoong.siang.song@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 30 ++++++++++++++++---
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 6088071cb1923..40dc14d1415f3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -322,6 +322,32 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 	if (!priv->dma_cap.av)
 		return -EOPNOTSUPP;
 
+	/* Port Transmit Rate and Speed Divider */
+	switch (priv->speed) {
+	case SPEED_10000:
+		ptr = 32;
+		speed_div = 10000000;
+		break;
+	case SPEED_5000:
+		ptr = 32;
+		speed_div = 5000000;
+		break;
+	case SPEED_2500:
+		ptr = 8;
+		speed_div = 2500000;
+		break;
+	case SPEED_1000:
+		ptr = 8;
+		speed_div = 1000000;
+		break;
+	case SPEED_100:
+		ptr = 4;
+		speed_div = 100000;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
 	mode_to_use = priv->plat->tx_queues_cfg[queue].mode_to_use;
 	if (mode_to_use == MTL_QUEUE_DCB && qopt->enable) {
 		ret = stmmac_dma_qmode(priv, priv->ioaddr, queue, MTL_QUEUE_AVB);
@@ -338,10 +364,6 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 		priv->plat->tx_queues_cfg[queue].mode_to_use = MTL_QUEUE_DCB;
 	}
 
-	/* Port Transmit Rate and Speed Divider */
-	ptr = (priv->speed == SPEED_100) ? 4 : 8;
-	speed_div = (priv->speed == SPEED_100) ? 100000 : 1000000;
-
 	/* Final adjustments for HW */
 	value = div_s64(qopt->idleslope * 1024ll * ptr, speed_div);
 	priv->plat->tx_queues_cfg[queue].idle_slope = value & GENMASK(31, 0);
-- 
2.27.0