net: ena: support new LLQ acceleration mode

New devices add a new hardware acceleration engine, which adds some
restrictions to the driver.
Metadata descriptor must be present for each packet and the maximum
burst size between two doorbells is now limited to a number
advertised by the device.

This patch adds:
1. A handshake protocol between the driver and the device, so the
device will enable the accelerated queues only when both sides
support it.

2. The driver support for the new acceleration engine:
2.1. Send metadata descriptor for each Tx packet.
2.2. Limit the number of packets sent between doorbells.(*)

(*) A previous driver implementation of this feature was comitted in
commit 05d62ca218f8 ("net: ena: add handling of llq max tx burst size")
however the design of the interface between the driver and device
changed since then. This change is reflected in this commit.

Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.h b/drivers/net/ethernet/amazon/ena/ena_com.h
index 4c98f6f07882..4287d47b2b0b 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h
@@ -127,6 +127,7 @@ struct ena_com_llq_info {
 	u16 descs_num_before_header;
 	u16 descs_per_entry;
 	u16 max_entries_in_tx_burst;
+	bool disable_meta_caching;
 };
 
 struct ena_com_io_cq {
@@ -189,6 +190,8 @@ struct ena_com_io_sq {
 	enum queue_direction direction;
 	enum ena_admin_placement_policy_type mem_queue_type;
 
+	bool disable_meta_caching;
+
 	u32 msix_vector;
 	struct ena_com_tx_meta cached_tx_meta;
 	struct ena_com_llq_info llq_info;