Merge branch 'stmmac-tx-coe'

Rohan G Thomas says:

====================
net: stmmac: Tx coe sw fallback

DW xGMAC IP can be synthesized such that it can support tx checksum
offloading only for a few initial tx queues. Also as Serge pointed
out, for the DW QoS IP, tx coe can be individually configured for
each tx queue. This patchset adds support for tx coe sw fallback for
those queues that don't support tx coe. Also, add binding for
snps,coe-unsupported property.

changelog v7:
* Updated commit message.
* Add blank lines around newly added dt binding.

changelog v6:
* Reworked patchset to cover DW QoS Ethernet IP also.

changelog v5:
* As rightly suggested by Serge, reworked redundant code.

changelog v4:
* Replaced tx_q_coe_lmt with bit flag.

changelog v3:
* Resend with complete email list.

changelog v2:
* Reformed binding description.
* Minor grammatical corrections in comments and commit messages.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 19 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
index ddf9522a5dc2..5c2769dc689a 100644
--- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
@@ -394,6 +394,11 @@ properties:
               When a PFC frame is received with priorities matching the bitmask,
               the queue is blocked from transmitting for the pause time specified
               in the PFC frame.
+
+          snps,coe-unsupported:
+            type: boolean
+            description: TX checksum offload is unsupported by the TX queue.
+
         allOf:
           - if:
               required:
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2206789802bf..9201ed778ebc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4401,6 +4401,16 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	WARN_ON(tx_q->tx_skbuff[first_entry]);
 
 	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
+	/* DWMAC IPs can be synthesized to support tx coe only for a few tx
+	 * queues. In that case, checksum offloading for those queues that don't
+	 * support tx coe needs to fallback to software checksum calculation.
+	 */
+	if (csum_insertion &&
+	    priv->plat->tx_queues_cfg[queue].coe_unsupported) {
+		if (unlikely(skb_checksum_help(skb)))
+			goto dma_map_err;
+		csum_insertion = !csum_insertion;
+	}
 
 	if (likely(priv->extend_desc))
 		desc = (struct dma_desc *)(tx_q->dma_etx + entry);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 0f28795e581c..a09014c9e7d0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -276,6 +276,9 @@ static int stmmac_mtl_setup(struct platform_device *pdev,
 			plat->tx_queues_cfg[queue].use_prio = true;
 		}
 
+		plat->tx_queues_cfg[queue].coe_unsupported =
+			of_property_read_bool(q_node, "snps,coe-unsupported");
+
 		queue++;
 	}
 	if (queue != plat->tx_queues_to_use) {
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index ce89cc3e4913..c0079a7574ae 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -139,6 +139,7 @@ struct stmmac_rxq_cfg {
 
 struct stmmac_txq_cfg {
 	u32 weight;
+	bool coe_unsupported;
 	u8 mode_to_use;
 	/* Credit Base Shaper parameters */
 	u32 send_slope;