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

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@socionext.com>
Reviewed-by: Yanteng Si <si.yanteng@linux.dev>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index edbf8994455d3730154369954fc934690b8ccfbe..f347e6390d29163accd855c0bdc62def422477c8 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -7221,6 +7221,21 @@ 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;