IB/mlx5: Support extended number of strides for Striding RQ

Extends the minimum single WQE strides from 64 to 8, which is exposed
by the "min_single_wqe_log_num_of_strides" field of striding_rq_caps.
Choose right number of strides based on FW capability.

Link: https://lore.kernel.org/r/20191115154555.247856-1-leon@kernel.orgSigned-off-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -1149,7 +1149,13 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 				MLX5_MIN_SINGLE_STRIDE_LOG_NUM_BYTES;
 			resp.striding_rq_caps.max_single_stride_log_num_of_bytes =
 				MLX5_MAX_SINGLE_STRIDE_LOG_NUM_BYTES;
-			resp.striding_rq_caps.min_single_wqe_log_num_of_strides =
+			if (MLX5_CAP_GEN(dev->mdev, ext_stride_num_range))
+				resp.striding_rq_caps
+					.min_single_wqe_log_num_of_strides =
+					MLX5_EXT_MIN_SINGLE_WQE_LOG_NUM_STRIDES;
+			else
+				resp.striding_rq_caps
+					.min_single_wqe_log_num_of_strides =
 					MLX5_MIN_SINGLE_WQE_LOG_NUM_STRIDES;
 			resp.striding_rq_caps.max_single_wqe_log_num_of_strides =
 				MLX5_MAX_SINGLE_WQE_LOG_NUM_STRIDES;

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -291,6 +291,7 @@ enum mlx5_ib_wq_flags {
 #define MLX5_MAX_SINGLE_WQE_LOG_NUM_STRIDES 16
 #define MLX5_MIN_SINGLE_STRIDE_LOG_NUM_BYTES 6
 #define MLX5_MAX_SINGLE_STRIDE_LOG_NUM_BYTES 13
+#define MLX5_EXT_MIN_SINGLE_WQE_LOG_NUM_STRIDES 3
 
 struct mlx5_ib_rwq {
 	struct ib_wq		ibwq;

drivers/infiniband/hw/mlx5/qp.c

@@ -5957,12 +5957,21 @@ static int  create_rq(struct mlx5_ib_rwq *rwq, struct ib_pd *pd,
 	}
 	MLX5_SET(wq, wq, log_wq_stride, rwq->log_rq_stride);
 	if (rwq->create_flags & MLX5_IB_WQ_FLAGS_STRIDING_RQ) {
+		/*
+		 * In Firmware number of strides in each WQE is:
+		 *   "512 * 2^single_wqe_log_num_of_strides"
+		 * Values 3 to 8 are accepted as 10 to 15, 9 to 18 are
+		 * accepted as 0 to 9
+		 */
+		static const u8 fw_map[] = { 10, 11, 12, 13, 14, 15, 0, 1,
+					     2,  3,  4,  5,  6,  7,  8, 9 };
 		MLX5_SET(wq, wq, two_byte_shift_en, rwq->two_byte_shift_en);
 		MLX5_SET(wq, wq, log_wqe_stride_size,
 			 rwq->single_stride_log_num_of_bytes -
 			 MLX5_MIN_SINGLE_STRIDE_LOG_NUM_BYTES);
-		MLX5_SET(wq, wq, log_wqe_num_of_strides, rwq->log_num_strides -
-			 MLX5_MIN_SINGLE_WQE_LOG_NUM_STRIDES);
+		MLX5_SET(wq, wq, log_wqe_num_of_strides,
+			 fw_map[rwq->log_num_strides -
+				MLX5_EXT_MIN_SINGLE_WQE_LOG_NUM_STRIDES]);
 	}
 	MLX5_SET(wq, wq, log_wq_sz, rwq->log_rq_size);
 	MLX5_SET(wq, wq, pd, to_mpd(pd)->pdn);
@@ -6037,6 +6046,19 @@ static int set_user_rq_size(struct mlx5_ib_dev *dev,
 	return 0;
 }
 
+static bool log_of_strides_valid(struct mlx5_ib_dev *dev, u32 log_num_strides)
+{
+	if ((log_num_strides > MLX5_MAX_SINGLE_WQE_LOG_NUM_STRIDES) ||
+	    (log_num_strides < MLX5_EXT_MIN_SINGLE_WQE_LOG_NUM_STRIDES))
+		return false;
+
+	if (!MLX5_CAP_GEN(dev->mdev, ext_stride_num_range) &&
+	    (log_num_strides < MLX5_MIN_SINGLE_WQE_LOG_NUM_STRIDES))
+		return false;
+
+	return true;
+}
+
 static int prepare_user_rq(struct ib_pd *pd,
 			   struct ib_wq_init_attr *init_attr,
 			   struct ib_udata *udata,
@@ -6084,12 +6106,14 @@ static int prepare_user_rq(struct ib_pd *pd,
 				    MLX5_MAX_SINGLE_STRIDE_LOG_NUM_BYTES);
 			return -EINVAL;
 		}
-		if ((ucmd.single_wqe_log_num_of_strides >
-		    MLX5_MAX_SINGLE_WQE_LOG_NUM_STRIDES) ||
-		     (ucmd.single_wqe_log_num_of_strides <
-			MLX5_MIN_SINGLE_WQE_LOG_NUM_STRIDES)) {
-			mlx5_ib_dbg(dev, "Invalid log num strides (%u. Range is %u - %u)\n",
+		if (!log_of_strides_valid(dev,
+					  ucmd.single_wqe_log_num_of_strides)) {
+			mlx5_ib_dbg(
+				dev,
+				"Invalid log num strides (%u. Range is %u - %u)\n",
 				ucmd.single_wqe_log_num_of_strides,
+				MLX5_CAP_GEN(dev->mdev, ext_stride_num_range) ?
+					MLX5_EXT_MIN_SINGLE_WQE_LOG_NUM_STRIDES :
 					MLX5_MIN_SINGLE_WQE_LOG_NUM_STRIDES,
 				MLX5_MAX_SINGLE_WQE_LOG_NUM_STRIDES);
 			return -EINVAL;