net: ena: add intr_moder_rx_interval to struct ena_com_dev and use it

BugLink: https://bugs.launchpad.net/bugs/1853180

Add intr_moder_rx_interval to struct ena_com_dev and use it as the
location where the interrupt moderation rx interval is saved, instead
of the interrupt moderation table.

This is done as a first step before removing the old interrupt moderation
code.
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 15619e72)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Khaled Elmously <khalid.elmously@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/net/ethernet/amazon/ena/ena_com.c

@@ -1297,9 +1297,6 @@ static int ena_com_init_interrupt_moderation_table(struct ena_com_dev *ena_dev)
 static void ena_com_update_intr_delay_resolution(struct ena_com_dev *ena_dev,
 						 u16 intr_delay_resolution)
 {
-	struct ena_intr_moder_entry *intr_moder_tbl = ena_dev->intr_moder_tbl;
-	unsigned int i;
-
 	if (!intr_delay_resolution) {
 		pr_err("Illegal intr_delay_resolution provided. Going to use default 1 usec resolution\n");
 		intr_delay_resolution = 1;
@@ -1307,8 +1304,7 @@ static void ena_com_update_intr_delay_resolution(struct ena_com_dev *ena_dev,
 	ena_dev->intr_delay_resolution = intr_delay_resolution;
 
 	/* update Rx */
-	for (i = 0; i < ENA_INTR_MAX_NUM_OF_LEVELS; i++)
-		intr_moder_tbl[i].intr_moder_interval /= intr_delay_resolution;
+	ena_dev->intr_moder_rx_interval /= intr_delay_resolution;
 
 	/* update Tx */
 	ena_dev->intr_moder_tx_interval /= intr_delay_resolution;
@@ -2798,11 +2794,8 @@ int ena_com_update_nonadaptive_moderation_interval_rx(struct ena_com_dev *ena_de
 		return -EFAULT;
 	}
 
-	/* We use LOWEST entry of moderation table for storing
-	 * nonadaptive interrupt coalescing values
-	 */
-	ena_dev->intr_moder_tbl[ENA_INTR_MODER_LOWEST].intr_moder_interval =
-		rx_coalesce_usecs / ena_dev->intr_delay_resolution;
+	ena_dev->intr_moder_rx_interval = rx_coalesce_usecs /
+		ena_dev->intr_delay_resolution;
 
 	return 0;
 }
@@ -2907,12 +2900,7 @@ unsigned int ena_com_get_nonadaptive_moderation_interval_tx(struct ena_com_dev *
 
 unsigned int ena_com_get_nonadaptive_moderation_interval_rx(struct ena_com_dev *ena_dev)
 {
-	struct ena_intr_moder_entry *intr_moder_tbl = ena_dev->intr_moder_tbl;
-
-	if (intr_moder_tbl)
-		return intr_moder_tbl[ENA_INTR_MODER_LOWEST].intr_moder_interval;
-
-	return 0;
+	return ena_dev->intr_moder_rx_interval;
 }
 
 void ena_com_init_intr_moderation_entry(struct ena_com_dev *ena_dev,

drivers/net/ethernet/amazon/ena/ena_com.h

@@ -93,7 +93,7 @@
 #define ENA_INTR_HIGHEST_BYTES          (192 * 1024)
 
 #define ENA_INTR_INITIAL_TX_INTERVAL_USECS		196
-#define ENA_INTR_INITIAL_RX_INTERVAL_USECS		4
+#define ENA_INTR_INITIAL_RX_INTERVAL_USECS		0
 #define ENA_INTR_DELAY_OLD_VALUE_WEIGHT			6
 #define ENA_INTR_DELAY_NEW_VALUE_WEIGHT			4
 #define ENA_INTR_MODER_LEVEL_STRIDE			2
@@ -376,7 +376,13 @@ struct ena_com_dev {
 	struct ena_host_attribute host_attr;
 	bool adaptive_coalescing;
 	u16 intr_delay_resolution;
+
+	/* interrupt moderation intervals are in usec divided by
+	 * intr_delay_resolution, which is supplied by the device.
+	 */
 	u32 intr_moder_tx_interval;
+	u32 intr_moder_rx_interval;
+
 	struct ena_intr_moder_entry *intr_moder_tbl;
 
 	struct ena_com_llq_info llq_info;

drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -3486,10 +3486,11 @@ static int ena_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	calc_queue_ctx.get_feat_ctx = &get_feat_ctx;
 	calc_queue_ctx.pdev = pdev;
 
-	/* initial Tx interrupt delay, Assumes 1 usec granularity.
+	/* Initial Tx and RX interrupt delay. Assumes 1 usec granularity.
 	* Updated during device initialization with the real granularity
 	*/
 	ena_dev->intr_moder_tx_interval = ENA_INTR_INITIAL_TX_INTERVAL_USECS;
+	ena_dev->intr_moder_rx_interval = ENA_INTR_INITIAL_RX_INTERVAL_USECS;
 	io_queue_num = ena_calc_io_queue_num(pdev, ena_dev, &get_feat_ctx);
 	rc = ena_calc_queue_size(&calc_queue_ctx);
 	if (rc || io_queue_num <= 0) {