Patch "net: stmmac: replace priv->speed with the portTransmitRate from the tc-cbs parameters" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net: stmmac: replace priv->speed with the portTransmitRate from the tc-cbs parameters

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-stmmac-replace-priv-speed-with-the-porttransmitr.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 986c1b3d501857dbffd83e8a71980335aa280af2
Author: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
Date:   Sat Jun 8 22:35:24 2024 +0800

    net: stmmac: replace priv->speed with the portTransmitRate from the tc-cbs parameters
    
    [ Upstream commit be27b896529787e23a35ae4befb6337ce73fcca0 ]
    
    The current cbs parameter depends on speed after uplinking,
    which is not needed and will report a configuration error
    if the port is not initially connected. The UAPI exposed by
    tc-cbs requires userspace to recalculate the send slope anyway,
    because the formula depends on port_transmit_rate (see man tc-cbs),
    which is not an invariant from tc's perspective. Therefore, we
    use offload->sendslope and offload->idleslope to derive the
    original port_transmit_rate from the CBS formula.
    
    Fixes: 1f705bc61aee ("net: stmmac: Add support for CBS QDISC")
    Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
    Reviewed-by: Wojciech Drewek <wojciech.drewek@xxxxxxxxx>
    Reviewed-by: Vladimir Oltean <olteanv@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20240608143524.2065736-1-xiaolei.wang@xxxxxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 08cffc0558743..a9b5f5ad1bac4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -341,10 +341,11 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 			struct tc_cbs_qopt_offload *qopt)
 {
 	u32 tx_queues_count = priv->plat->tx_queues_to_use;
+	s64 port_transmit_rate_kbps;
 	u32 queue = qopt->queue;
-	u32 ptr, speed_div;
 	u32 mode_to_use;
 	u64 value;
+	u32 ptr;
 	int ret;
 
 	/* Queue 0 is not AVB capable */
@@ -353,30 +354,26 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 	if (!priv->dma_cap.av)
 		return -EOPNOTSUPP;
 
+	port_transmit_rate_kbps = qopt->idleslope - qopt->sendslope;
+
 	/* Port Transmit Rate and Speed Divider */
-	switch (priv->speed) {
+	switch (div_s64(port_transmit_rate_kbps, 1000)) {
 	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;
+		netdev_err(priv->dev,
+			   "Invalid portTransmitRate %lld (idleSlope - sendSlope)\n",
+			   port_transmit_rate_kbps);
+		return -EINVAL;
 	}
 
 	mode_to_use = priv->plat->tx_queues_cfg[queue].mode_to_use;
@@ -396,10 +393,10 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 	}
 
 	/* Final adjustments for HW */
-	value = div_s64(qopt->idleslope * 1024ll * ptr, speed_div);
+	value = div_s64(qopt->idleslope * 1024ll * ptr, port_transmit_rate_kbps);
 	priv->plat->tx_queues_cfg[queue].idle_slope = value & GENMASK(31, 0);
 
-	value = div_s64(-qopt->sendslope * 1024ll * ptr, speed_div);
+	value = div_s64(-qopt->sendslope * 1024ll * ptr, port_transmit_rate_kbps);
 	priv->plat->tx_queues_cfg[queue].send_slope = value & GENMASK(31, 0);
 
 	value = qopt->hicredit * 1024ll * 8;