6 files changed, 85 insertions, 17 deletions

diff --git a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
index 9f80b73f90b1..82cff1e120f8 100644
--- a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
+++ b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
@@ -524,6 +524,11 @@ struct ena_admin_feature_llq_desc {
 
 	/* the stride control the driver selected to use */
 	u16 descriptors_stride_ctrl_enabled;
+
+	/* Maximum size in bytes taken by llq entries in a single tx burst.
+	 * Set to 0 when there is no such limit.
+	 */
+	u32 max_tx_burst_size;
 };
 
 struct ena_admin_queue_feature_desc {
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c
index 7f8266b191ae..bd0d785b211e 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -396,6 +396,10 @@ static int ena_com_init_io_sq(struct ena_com_dev *ena_dev,
 		       0x0, io_sq->llq_info.desc_list_entry_size);
 		io_sq->llq_buf_ctrl.descs_left_in_line =
 			io_sq->llq_info.descs_num_before_header;
+
+		if (io_sq->llq_info.max_entries_in_tx_burst > 0)
+			io_sq->entries_in_tx_burst_left =
+				io_sq->llq_info.max_entries_in_tx_burst;
 	}
 
 	io_sq->tail = 0;
@@ -727,6 +731,9 @@ static int ena_com_config_llq_info(struct ena_com_dev *ena_dev,
 		       supported_feat, llq_info->descs_num_before_header);
 	}
 
+	llq_info->max_entries_in_tx_burst =
+		(u16)(llq_features->max_tx_burst_size /	llq_default_cfg->llq_ring_entry_size_value);
+
 	rc = ena_com_set_llq(ena_dev);
 	if (rc)
 		pr_err("Cannot set LLQ configuration: %d\n", rc);
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.h b/drivers/net/ethernet/amazon/ena/ena_com.h
index 078d6f2b4f39..f0cb043afcc3 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h
@@ -159,6 +159,7 @@ struct ena_com_llq_info {
 	u16 desc_list_entry_size;
 	u16 descs_num_before_header;
 	u16 descs_per_entry;
+	u16 max_entries_in_tx_burst;
 };
 
 struct ena_com_io_cq {
@@ -238,6 +239,7 @@ struct ena_com_io_sq {
 	u8 phase;
 	u8 desc_entry_size;
 	u8 dma_addr_bits;
+	u16 entries_in_tx_burst_left;
 } ____cacheline_aligned;
 
 struct ena_com_admin_cq {
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.c b/drivers/net/ethernet/amazon/ena/ena_eth_com.c
index f6c2d3855be8..cad2b572808e 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.c
@@ -82,6 +82,17 @@ static inline int ena_com_write_bounce_buffer_to_dev(struct ena_com_io_sq *io_sq
 	dst_tail_mask = io_sq->tail & (io_sq->q_depth - 1);
 	dst_offset = dst_tail_mask * llq_info->desc_list_entry_size;
 
+	if (is_llq_max_tx_burst_exists(io_sq)) {
+		if (unlikely(!io_sq->entries_in_tx_burst_left)) {
+			pr_err("Error: trying to send more packets than tx burst allows\n");
+			return -ENOSPC;
+		}
+
+		io_sq->entries_in_tx_burst_left--;
+		pr_debug("decreasing entries_in_tx_burst_left of queue %d to %d\n",
+			 io_sq->qid, io_sq->entries_in_tx_burst_left);
+	}
+
 	/* Make sure everything was written into the bounce buffer before
 	 * writing the bounce buffer to the device
 	 */
@@ -274,23 +285,6 @@ static inline u16 ena_com_cdesc_rx_pkt_get(struct ena_com_io_cq *io_cq,
 	return count;
 }
 
-static inline bool ena_com_meta_desc_changed(struct ena_com_io_sq *io_sq,
-					     struct ena_com_tx_ctx *ena_tx_ctx)
-{
-	int rc;
-
-	if (ena_tx_ctx->meta_valid) {
-		rc = memcmp(&io_sq->cached_tx_meta,
-			    &ena_tx_ctx->ena_meta,
-			    sizeof(struct ena_com_tx_meta));
-
-		if (unlikely(rc != 0))
-			return true;
-	}
-
-	return false;
-}
-
 static inline int ena_com_create_and_store_tx_meta_desc(struct ena_com_io_sq *io_sq,
 							struct ena_com_tx_ctx *ena_tx_ctx)
 {
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.h b/drivers/net/ethernet/amazon/ena/ena_eth_com.h
index 340d02b64ca6..0a3d9180e40e 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.h
@@ -125,8 +125,55 @@ static inline bool ena_com_sq_have_enough_space(struct ena_com_io_sq *io_sq,
 	return ena_com_free_desc(io_sq) > temp;
 }
 
+static inline bool ena_com_meta_desc_changed(struct ena_com_io_sq *io_sq,
+					     struct ena_com_tx_ctx *ena_tx_ctx)
+{
+	if (!ena_tx_ctx->meta_valid)
+		return false;
+
+	return !!memcmp(&io_sq->cached_tx_meta,
+			&ena_tx_ctx->ena_meta,
+			sizeof(struct ena_com_tx_meta));
+}
+
+static inline bool is_llq_max_tx_burst_exists(struct ena_com_io_sq *io_sq)
+{
+	return (io_sq->mem_queue_type == ENA_ADMIN_PLACEMENT_POLICY_DEV) &&
+	       io_sq->llq_info.max_entries_in_tx_burst > 0;
+}
+
+static inline bool ena_com_is_doorbell_needed(struct ena_com_io_sq *io_sq,
+					      struct ena_com_tx_ctx *ena_tx_ctx)
+{
+	struct ena_com_llq_info *llq_info;
+	int descs_after_first_entry;
+	int num_entries_needed = 1;
+	u16 num_descs;
+
+	if (!is_llq_max_tx_burst_exists(io_sq))
+		return false;
+
+	llq_info = &io_sq->llq_info;
+	num_descs = ena_tx_ctx->num_bufs;
+
+	if (unlikely(ena_com_meta_desc_changed(io_sq, ena_tx_ctx)))
+		++num_descs;
+
+	if (num_descs > llq_info->descs_num_before_header) {
+		descs_after_first_entry = num_descs - llq_info->descs_num_before_header;
+		num_entries_needed += DIV_ROUND_UP(descs_after_first_entry,
+						   llq_info->descs_per_entry);
+	}
+
+	pr_debug("queue: %d num_descs: %d num_entries_needed: %d\n", io_sq->qid,
+		 num_descs, num_entries_needed);
+
+	return num_entries_needed > io_sq->entries_in_tx_burst_left;
+}
+
 static inline int ena_com_write_sq_doorbell(struct ena_com_io_sq *io_sq)
 {
+	u16 max_entries_in_tx_burst = io_sq->llq_info.max_entries_in_tx_burst;
 	u16 tail = io_sq->tail;
 
 	pr_debug("write submission queue doorbell for queue: %d tail: %d\n",
@@ -134,6 +181,12 @@ static inline int ena_com_write_sq_doorbell(struct ena_com_io_sq *io_sq)
 
 	writel(tail, io_sq->db_addr);
 
+	if (is_llq_max_tx_burst_exists(io_sq)) {
+		pr_debug("reset available entries in tx burst for queue %d to %d\n",
+			 io_sq->qid, max_entries_in_tx_burst);
+		io_sq->entries_in_tx_burst_left = max_entries_in_tx_burst;
+	}
+
 	return 0;
 }
 
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 9c83642922c7..d2b82f917d3f 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -2172,6 +2172,13 @@ static netdev_tx_t ena_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* set flags and meta data */
 	ena_tx_csum(&ena_tx_ctx, skb);
 
+	if (unlikely(ena_com_is_doorbell_needed(tx_ring->ena_com_io_sq, &ena_tx_ctx))) {
+		netif_dbg(adapter, tx_queued, dev,
+			  "llq tx max burst size of queue %d achieved, writing doorbell to send burst\n",
+			  qid);
+		ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
+	}
+
 	/* prepare the packet's descriptors to dma engine */
 	rc = ena_com_prepare_tx(tx_ring->ena_com_io_sq, &ena_tx_ctx,
 				&nb_hw_desc);