[PATCH V2 net-next 01/14] net: ena: add support for the rx offset feature

[<akiyano@amazon.com>]

From: Arthur Kiyanovski <akiyano@amazon.com>

Newer ENA devices can write data to rx buffers with an offset
from the beginning of the buffer.

This commit adds support for this feature in the driver.

Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
---
 .../net/ethernet/amazon/ena/ena_admin_defs.h   |  5 ++++-
 drivers/net/ethernet/amazon/ena/ena_eth_com.c  | 18 ++++++++++++------
 drivers/net/ethernet/amazon/ena/ena_eth_com.h  |  1 +
 .../net/ethernet/amazon/ena/ena_eth_io_defs.h  |  4 +++-
 drivers/net/ethernet/amazon/ena/ena_netdev.c   |  8 ++++++++
 5 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
index 7be3dcbf3d16..727836f638ad 100644
--- a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
+++ b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h
@@ -813,7 +813,8 @@ struct ena_admin_host_info {
 
 	u16 reserved;
 
-	/* 1 :0 : reserved
+	/* 0 : reserved
+	 * 1 : rx_offset
 	 * 2 : interrupt_moderation
 	 * 31:3 : reserved
 	 */
@@ -1124,6 +1125,8 @@ struct ena_admin_ena_mmio_req_read_less_resp {
 #define ENA_ADMIN_HOST_INFO_DEVICE_MASK                     GENMASK(7, 3)
 #define ENA_ADMIN_HOST_INFO_BUS_SHIFT                       8
 #define ENA_ADMIN_HOST_INFO_BUS_MASK                        GENMASK(15, 8)
+#define ENA_ADMIN_HOST_INFO_RX_OFFSET_SHIFT                 1
+#define ENA_ADMIN_HOST_INFO_RX_OFFSET_MASK                  BIT(1)
 #define ENA_ADMIN_HOST_INFO_INTERRUPT_MODERATION_SHIFT      2
 #define ENA_ADMIN_HOST_INFO_INTERRUPT_MODERATION_MASK       BIT(2)
 
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.c b/drivers/net/ethernet/amazon/ena/ena_eth_com.c
index 2845ac277724..a014f514c069 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.c
@@ -519,7 +519,7 @@ int ena_com_rx_pkt(struct ena_com_io_cq *io_cq,
 	struct ena_eth_io_rx_cdesc_base *cdesc = NULL;
 	u16 cdesc_idx = 0;
 	u16 nb_hw_desc;
-	u16 i;
+	u16 i = 0;
 
 	WARN(io_cq->direction != ENA_COM_IO_QUEUE_DIRECTION_RX, "wrong Q type");
 
@@ -538,13 +538,19 @@ int ena_com_rx_pkt(struct ena_com_io_cq *io_cq,
 		return -ENOSPC;
 	}
 
-	for (i = 0; i < nb_hw_desc; i++) {
+	cdesc = ena_com_rx_cdesc_idx_to_ptr(io_cq, cdesc_idx);
+	ena_rx_ctx->pkt_offset = cdesc->offset;
+
+	do {
+		ena_buf[i].len = cdesc->length;
+		ena_buf[i].req_id = cdesc->req_id;
+
+		if (++i >= nb_hw_desc)
+			break;
+
 		cdesc = ena_com_rx_cdesc_idx_to_ptr(io_cq, cdesc_idx + i);
 
-		ena_buf->len = cdesc->length;
-		ena_buf->req_id = cdesc->req_id;
-		ena_buf++;
-	}
+	} while (1);
 
 	/* Update SQ head ptr */
 	io_sq->next_to_comp += nb_hw_desc;
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.h b/drivers/net/ethernet/amazon/ena/ena_eth_com.h
index 77986c0ea52c..9834b5cdb655 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.h
@@ -73,6 +73,7 @@ struct ena_com_rx_ctx {
 	u32 hash;
 	u16 descs;
 	int max_bufs;
+	u8 pkt_offset;
 };
 
 int ena_com_prepare_tx(struct ena_com_io_sq *io_sq,
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_io_defs.h b/drivers/net/ethernet/amazon/ena/ena_eth_io_defs.h
index 00e0f056a741..ee28fb067d8c 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_io_defs.h
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_io_defs.h
@@ -264,7 +264,9 @@ struct ena_eth_io_rx_cdesc_base {
 
 	u16 sub_qid;
 
-	u16 reserved;
+	u8 offset;
+
+	u8 reserved;
 };
 
 /* 8-word format */
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 85b87ed02dd5..33578297dc56 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1435,6 +1435,8 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 
 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_info->page,
 				rx_info->page_offset, len, ENA_PAGE_SIZE);
+		/* The offset is non zero only for the first buffer */
+		rx_info->page_offset = 0;
 
 		netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
 			  "rx skb updated. len %d. data_len %d\n",
@@ -1590,6 +1592,7 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 {
 	u16 next_to_clean = rx_ring->next_to_clean;
 	struct ena_com_rx_ctx ena_rx_ctx;
+	struct ena_rx_buffer *rx_info;
 	struct ena_adapter *adapter;
 	u32 res_budget, work_done;
 	int rx_copybreak_pkt = 0;
@@ -1614,6 +1617,7 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 		ena_rx_ctx.ena_bufs = rx_ring->ena_bufs;
 		ena_rx_ctx.max_bufs = rx_ring->sgl_size;
 		ena_rx_ctx.descs = 0;
+		ena_rx_ctx.pkt_offset = 0;
 		rc = ena_com_rx_pkt(rx_ring->ena_com_io_cq,
 				    rx_ring->ena_com_io_sq,
 				    &ena_rx_ctx);
@@ -1623,6 +1627,9 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 		if (unlikely(ena_rx_ctx.descs == 0))
 			break;
 
+		rx_info = &rx_ring->rx_buffer_info[rx_ring->ena_bufs[0].req_id];
+		rx_info->page_offset = ena_rx_ctx.pkt_offset;
+
 		netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
 			  "rx_poll: q %d got packet from ena. descs #: %d l3 proto %d l4 proto %d hash: %x\n",
 			  rx_ring->qid, ena_rx_ctx.descs, ena_rx_ctx.l3_proto,
@@ -3111,6 +3118,7 @@ static void ena_config_host_info(struct ena_com_dev *ena_dev,
 	host_info->num_cpus = num_online_cpus();
 
 	host_info->driver_supported_features =
+		ENA_ADMIN_HOST_INFO_RX_OFFSET_MASK |
 		ENA_ADMIN_HOST_INFO_INTERRUPT_MODERATION_MASK;
 
 	rc = ena_com_set_host_attributes(ena_dev);
-- 
2.23.1