Mixed approach allows using higher interrupt threshold (increased back to
15 packets), useful in high throughput. In case of small amount of data
or very short TX queues HR timer ensures releasing buffers with small
latency.

Along with existing tx_done processing by coalescing interrupts this
commit enables triggering HR timer each time the packets are sent.
Time threshold can also be configured, using ethtool.

Signed-off-by: Marcin Wojtas <redacted>
Signed-off-by: Simon Guinot <redacted>
---
 drivers/net/ethernet/marvell/mvneta.c | 89 +++++++++++++++++++++++++++++++++--
 1 file changed, 85 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 9c9e858..f5acaf6 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c

@@ -21,6 +21,8 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/if_vlan.h>
+#include <linux/hrtimer.h>
+#include <linux/ktime.h>

 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <linux/io.h>

@@ -226,7 +228,8 @@
 /* Various constants */
 
 /* Coalescing */
-#define MVNETA_TXDONE_COAL_PKTS		1
+#define MVNETA_TXDONE_COAL_PKTS		15
+#define MVNETA_TXDONE_COAL_USEC		100

 #define MVNETA_RX_COAL_PKTS		32
 #define MVNETA_RX_COAL_USEC		100
 

@@ -356,6 +359,11 @@ struct mvneta_port {
 	struct net_device *dev;
 	struct notifier_block cpu_notifier;
 
+	/* Egress finalization */
+	struct tasklet_struct tx_done_tasklet;
+	struct hrtimer tx_done_timer;
+	bool timer_scheduled;