net: stmmac: fix cbs configuration

Sending again, because forgot to include net-dev.

The QoS IP does not accept AVB capabilities to default/queue 0, this way we
guarantee 75% bandwidth for AVB. This patch assures that only queues >= 1
gets CBS confgured. Additional info was also added to stmmac.txt.

Reported-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
index 784d988..f652b0c 100644 (file)
--- a/Documentation/devicetree/bindings/net/stmmac.txt
+++ b/Documentation/devicetree/bindings/net/stmmac.txt
@@ -103,6 +103,8 @@ Optional properties:
                - Choose one of these modes:
                        - snps,dcb-algorithm: TX queue will be working in DCB
                        - snps,avb-algorithm: TX queue will be working in AVB
+                         [Attention] Queue 0 is reserved for legacy traffic
+                         and so no AVB is available in this queue.
                - Configure Credit Base Shaper (if AVB Mode selected):
                        - snps,send_slope: enable Low Power Interface
                        - snps,idle_slope: unlock on WoL

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 43361f3..c1c6319 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1880,7 +1880,8 @@ static void stmmac_configure_cbs(struct stmmac_priv *priv)
        u32 mode_to_use;
        u32 queue;
 
-       for (queue = 0; queue < tx_queues_count; queue++) {
+       /* queue 0 is reserved for legacy traffic */
+       for (queue = 1; queue < tx_queues_count; queue++) {
                mode_to_use = priv->plat->tx_queues_cfg[queue].mode_to_use;
                if (mode_to_use == MTL_QUEUE_DCB)
                        continue;