Patch "net: stmmac: Limit the number of MTL queues to hardware capability" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    net: stmmac: Limit the number of MTL queues to hardware capability

to the 6.6-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-limit-the-number-of-mtl-queues-to-hardwar.patch
and it can be found in the queue-6.6 subdirectory.

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



commit 76399ff82c82383be660b14d7425bc86166de7e5
Author: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
Date:   Mon Jan 27 10:38:18 2025 +0900

    net: stmmac: Limit the number of MTL queues to hardware capability
    
    [ Upstream commit f5fb35a3d6b36d378b2e2ecbfb9caa337d5428e6 ]
    
    The number of MTL queues to use is specified by the parameter
    "snps,{tx,rx}-queues-to-use" from stmmac_platform layer.
    
    However, the maximum numbers of queues are constrained by upper limits
    determined by the capability of each hardware feature. It's appropriate
    to limit the values not to exceed the upper limit values and display
    a warning message.
    
    This only works if the hardware capability has the upper limit values.
    
    Fixes: d976a525c371 ("net: stmmac: multiple queues dt configuration")
    Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
    Reviewed-by: Yanteng Si <si.yanteng@xxxxxxxxx>
    Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d6ee90fef2eca..48ad12bca9566 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -7103,6 +7103,21 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 	if (priv->dma_cap.tsoen)
 		dev_info(priv->device, "TSO supported\n");
 
+	if (priv->dma_cap.number_rx_queues &&
+	    priv->plat->rx_queues_to_use > priv->dma_cap.number_rx_queues) {
+		dev_warn(priv->device,
+			 "Number of Rx queues (%u) exceeds dma capability\n",
+			 priv->plat->rx_queues_to_use);
+		priv->plat->rx_queues_to_use = priv->dma_cap.number_rx_queues;
+	}
+	if (priv->dma_cap.number_tx_queues &&
+	    priv->plat->tx_queues_to_use > priv->dma_cap.number_tx_queues) {
+		dev_warn(priv->device,
+			 "Number of Tx queues (%u) exceeds dma capability\n",
+			 priv->plat->tx_queues_to_use);
+		priv->plat->tx_queues_to_use = priv->dma_cap.number_tx_queues;
+	}
+
 	priv->hw->vlan_fail_q_en =
 		(priv->plat->flags & STMMAC_FLAG_VLAN_FAIL_Q_EN);
 	priv->hw->vlan_fail_q = priv->plat->vlan_fail_q;