[PATCH v2 3/6] net: ocelot: pre-compute injection frame header content

["Clément Léger" <clement.leger@bootlin.com>]

IFH preparation can take quite some time on slow processors (up to 5% in
a iperf3 test for instance). In order to reduce the cost of this
preparation, pre-compute IFH since most of the parameters are fixed per
port. Only rew_op and vlan tag will be set when sending if different
than 0. This allows to remove entirely the calls to packing() with basic
usage. In the same time, export this function that will be used by FDMA.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 23 ++++++++++++++++++-----
 include/soc/mscc/ocelot.h          |  5 +++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index e6c18b598d5c..97693772595b 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1076,20 +1076,29 @@ bool ocelot_can_inject(struct ocelot *ocelot, int grp)
 }
 EXPORT_SYMBOL(ocelot_can_inject);
 
+void ocelot_ifh_port_set(void *ifh, struct ocelot_port *port, u32 rew_op,
+			 u32 vlan_tag)
+{
+	memcpy(ifh, port->ifh, OCELOT_TAG_LEN);
+
+	if (vlan_tag)
+		ocelot_ifh_set_vlan_tci(ifh, vlan_tag);
+	if (rew_op)
+		ocelot_ifh_set_rew_op(ifh, rew_op);
+}
+EXPORT_SYMBOL(ocelot_ifh_port_set);
+
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb)
 {
+	struct ocelot_port *port_s = ocelot->ports[port];
 	u32 ifh[OCELOT_TAG_LEN / 4] = {0};
 	unsigned int i, count, last;
 
 	ocelot_write_rix(ocelot, QS_INJ_CTRL_GAP_SIZE(1) |
 			 QS_INJ_CTRL_SOF, QS_INJ_CTRL, grp);
 
-	ocelot_ifh_set_bypass(ifh, 1);
-	ocelot_ifh_set_dest(ifh, BIT_ULL(port));
-	ocelot_ifh_set_tag_type(ifh, IFH_TAG_TYPE_C);
-	ocelot_ifh_set_vlan_tci(ifh, skb_vlan_tag_get(skb));
-	ocelot_ifh_set_rew_op(ifh, rew_op);
+	ocelot_ifh_port_set(ifh, port_s, rew_op, skb_vlan_tag_get(skb));
 
 	for (i = 0; i < OCELOT_TAG_LEN / 4; i++)
 		ocelot_write_rix(ocelot, ifh[i], QS_INJ_WR, grp);
@@ -2128,6 +2137,10 @@ void ocelot_init_port(struct ocelot *ocelot, int port)
 
 	skb_queue_head_init(&ocelot_port->tx_skbs);
 
+	ocelot_ifh_set_bypass(ocelot_port->ifh, 1);
+	ocelot_ifh_set_dest(ocelot_port->ifh, BIT_ULL(port));
+	ocelot_ifh_set_tag_type(ocelot_port->ifh, IFH_TAG_TYPE_C);
+
 	/* Basic L2 initialization */
 
 	/* Set MAC IFG Gaps
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index fef3a36b0210..b3381c90ff3e 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -6,6 +6,7 @@
 #define _SOC_MSCC_OCELOT_H
 
 #include <linux/ptp_clock_kernel.h>
+#include <linux/dsa/ocelot.h>
 #include <linux/net_tstamp.h>
 #include <linux/if_vlan.h>
 #include <linux/regmap.h>
@@ -623,6 +624,8 @@ struct ocelot_port {
 
 	struct net_device		*bridge;
 	u8				stp_state;
+
+	u8				ifh[OCELOT_TAG_LEN];
 };
 
 struct ocelot {
@@ -754,6 +757,8 @@ void __ocelot_target_write_ix(struct ocelot *ocelot, enum ocelot_target target,
 bool ocelot_can_inject(struct ocelot *ocelot, int grp);
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb);
+void ocelot_ifh_port_set(void *ifh, struct ocelot_port *port, u32 rew_op,
+			 u32 vlan_tag);
 int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **skb);
 void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp);
 
-- 
2.33.0