net: ipa: make endpoint HOLB drop configurable

Add a new Boolean flag for RX endpoints defining whether HOLB drop
is initially enabled or disabled for the endpoint.  All existing AP
endpoints should have HOLB drop disabled.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_endpoint.c

@@ -1554,8 +1554,12 @@ static void ipa_endpoint_program(struct ipa_endpoint *endpoint)
 	ipa_endpoint_init_hdr_metadata_mask(endpoint);
 	ipa_endpoint_init_mode(endpoint);
 	ipa_endpoint_init_aggr(endpoint);
-	if (!endpoint->toward_ipa)
-		ipa_endpoint_init_hol_block_disable(endpoint);
+	if (!endpoint->toward_ipa) {
+		if (endpoint->config.rx.holb_drop)
+			ipa_endpoint_init_hol_block_enable(endpoint, 0);
+		else
+			ipa_endpoint_init_hol_block_disable(endpoint);
+	}
 	ipa_endpoint_init_deaggr(endpoint);
 	ipa_endpoint_init_rsrc_grp(endpoint);
 	ipa_endpoint_init_seq(endpoint);

drivers/net/ipa/ipa_endpoint.h

@@ -60,6 +60,7 @@ struct ipa_endpoint_tx {
  * @buffer_size:	requested receive buffer size (bytes)
  * @pad_align:		power-of-2 boundary to which packet payload is aligned
  * @aggr_close_eof:	whether aggregation closes on end-of-frame
+ * @holb_drop:		whether to drop packets to avoid head-of-line blocking
  *
  * With each packet it transfers, the IPA hardware can perform certain
  * transformations of its packet data.  One of these is adding pad bytes
@@ -74,6 +75,7 @@ struct ipa_endpoint_rx {
 	u32 buffer_size;
 	u32 pad_align;
 	bool aggr_close_eof;
+	bool holb_drop;
 };
 
 /**