net/mlx5e: Read max WQEBBs on the SQ from firmware

Prior to this patch the maximal value for max WQEBBs (WQE Basic Blocks,
where WQE is a Work Queue Element) on the TX side was assumed to be 16
(fixed value). All firmware versions till today comply to this. In order
to be more flexible and resilient, read from FW the corresponding:
max_wqe_sz_sq. This value describes the maximum WQE size given in bytes,
thus max WQEBBs is given by the division in WQEBB's byte size. The
driver uses the top between 16 and the division result. This ensures
synchronization between driver and firmware and avoids unexpected
behavior. Store this value on the different SQs (Send Queues) for easy
access.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
index b789af07829c..67dd4f415b7a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h
@@ -431,10 +431,10 @@ mlx5e_set_eseg_swp(struct sk_buff *skb, struct mlx5_wqe_eth_seg *eseg,
 	}
 }
 
-static inline u16 mlx5e_stop_room_for_wqe(u16 wqe_size)
-{
-	BUILD_BUG_ON(PAGE_SIZE / MLX5_SEND_WQE_BB < MLX5_SEND_WQE_MAX_WQEBBS);
+#define MLX5E_STOP_ROOM(wqebbs) ((wqebbs) * 2 - 1)
 
+static inline u16 mlx5e_stop_room_for_wqe(struct mlx5_core_dev *mdev, u16 wqe_size)
+{
 	/* A WQE must not cross the page boundary, hence two conditions:
 	 * 1. Its size must not exceed the page size.
 	 * 2. If the WQE size is X, and the space remaining in a page is less
@@ -443,18 +443,28 @@ static inline u16 mlx5e_stop_room_for_wqe(u16 wqe_size)
 	 *    stop room of X-1 + X.
 	 * WQE size is also limited by the hardware limit.
 	 */
+	WARN_ONCE(wqe_size > mlx5e_get_max_sq_wqebbs(mdev),
+		  "wqe_size %u is greater than max SQ WQEBBs %u",
+		  wqe_size, mlx5e_get_max_sq_wqebbs(mdev));
 
-	if (__builtin_constant_p(wqe_size))
-		BUILD_BUG_ON(wqe_size > MLX5_SEND_WQE_MAX_WQEBBS);
-	else
-		WARN_ON_ONCE(wqe_size > MLX5_SEND_WQE_MAX_WQEBBS);
 
-	return wqe_size * 2 - 1;
+	return MLX5E_STOP_ROOM(wqe_size);
+}
+
+static inline u16 mlx5e_stop_room_for_max_wqe(struct mlx5_core_dev *mdev)
+{
+	return MLX5E_STOP_ROOM(mlx5e_get_max_sq_wqebbs(mdev));
 }
 
 static inline bool mlx5e_icosq_can_post_wqe(struct mlx5e_icosq *sq, u16 wqe_size)
 {
-	u16 room = sq->reserved_room + mlx5e_stop_room_for_wqe(wqe_size);
+	u16 room = sq->reserved_room;
+
+	WARN_ONCE(wqe_size > sq->max_sq_wqebbs,
+		  "wqe_size %u is greater than max SQ WQEBBs %u",
+		  wqe_size, sq->max_sq_wqebbs);
+
+	room += MLX5E_STOP_ROOM(wqe_size);
 
 	return mlx5e_wqc_has_room_for(&sq->wq, sq->cc, sq->pc, room);
 }