RDMA/efa: Introduce SRD RNR retry

This patch introduces the ability to configure SRD QPs with the RNR retry
parameter when issuing a modify QP command.

In addition, a capability bit was added to report support to the userspace
library.

Link: https://lore.kernel.org/r/20200731060420.17053-5-galpress@amazon.comReviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/efa/efa_admin_cmds_defs.h

@@ -197,7 +197,8 @@ struct efa_admin_modify_qp_cmd {
 	 * 2 : qkey
 	 * 3 : sq_psn
 	 * 4 : sq_drained_async_notify
-	 * 31:5 : reserved
+	 * 5 : rnr_retry
+	 * 31:6 : reserved
 	 */
 	u32 modify_mask;
 
@@ -219,8 +220,8 @@ struct efa_admin_modify_qp_cmd {
 	/* Enable async notification when SQ is drained */
 	u8 sq_drained_async_notify;
 
-	/* MBZ */
-	u8 reserved1;
+	/* Number of RNR retries (valid only for SRD QPs) */
+	u8 rnr_retry;
 
 	/* MBZ */
 	u16 reserved2;
@@ -255,8 +256,8 @@ struct efa_admin_query_qp_resp {
 	/* Indicates that draining is in progress */
 	u8 sq_draining;
 
-	/* MBZ */
-	u8 reserved1;
+	/* Number of RNR retries (valid only for SRD QPs) */
+	u8 rnr_retry;
 
 	/* MBZ */
 	u16 reserved2;
@@ -573,7 +574,9 @@ struct efa_admin_feature_device_attr_desc {
 	/*
 	 * 0 : rdma_read - If set, RDMA Read is supported on
 	 *    TX queues
-	 * 31:1 : reserved - MBZ
+	 * 1 : rnr_retry - If set, RNR retry is supported on
+	 *    modify QP command
+	 * 31:2 : reserved - MBZ
 	 */
 	u32 device_caps;
 
@@ -865,6 +868,7 @@ struct efa_admin_host_info {
 #define EFA_ADMIN_MODIFY_QP_CMD_QKEY_MASK                   BIT(2)
 #define EFA_ADMIN_MODIFY_QP_CMD_SQ_PSN_MASK                 BIT(3)
 #define EFA_ADMIN_MODIFY_QP_CMD_SQ_DRAINED_ASYNC_NOTIFY_MASK BIT(4)
+#define EFA_ADMIN_MODIFY_QP_CMD_RNR_RETRY_MASK              BIT(5)
 
 /* reg_mr_cmd */
 #define EFA_ADMIN_REG_MR_CMD_PHYS_PAGE_SIZE_SHIFT_MASK      GENMASK(4, 0)
@@ -882,6 +886,7 @@ struct efa_admin_host_info {
 
 /* feature_device_attr_desc */
 #define EFA_ADMIN_FEATURE_DEVICE_ATTR_DESC_RDMA_READ_MASK   BIT(0)
+#define EFA_ADMIN_FEATURE_DEVICE_ATTR_DESC_RNR_RETRY_MASK   BIT(1)
 
 /* host_info */
 #define EFA_ADMIN_HOST_INFO_DRIVER_MODULE_TYPE_MASK         GENMASK(7, 0)

drivers/infiniband/hw/efa/efa_com_cmd.c

@@ -76,6 +76,7 @@ int efa_com_modify_qp(struct efa_com_dev *edev,
 	cmd.qkey = params->qkey;
 	cmd.sq_psn = params->sq_psn;
 	cmd.sq_drained_async_notify = params->sq_drained_async_notify;
+	cmd.rnr_retry = params->rnr_retry;
 
 	err = efa_com_cmd_exec(aq,
 			       (struct efa_admin_aq_entry *)&cmd,
@@ -121,6 +122,7 @@ int efa_com_query_qp(struct efa_com_dev *edev,
 	result->qkey = resp.qkey;
 	result->sq_draining = resp.sq_draining;
 	result->sq_psn = resp.sq_psn;
+	result->rnr_retry = resp.rnr_retry;
 
 	return 0;
 }

drivers/infiniband/hw/efa/efa_com_cmd.h

@@ -47,6 +47,7 @@ struct efa_com_modify_qp_params {
 	u32 qkey;
 	u32 sq_psn;
 	u8 sq_drained_async_notify;
+	u8 rnr_retry;
 };
 
 struct efa_com_query_qp_params {
@@ -58,6 +59,7 @@ struct efa_com_query_qp_result {
 	u32 qkey;
 	u32 sq_draining;
 	u32 sq_psn;
+	u8 rnr_retry;
 };
 
 struct efa_com_destroy_qp_params {

drivers/infiniband/hw/efa/efa_verbs.c

@@ -223,6 +223,9 @@ int efa_query_device(struct ib_device *ibdev,
 		if (EFA_DEV_CAP(dev, RDMA_READ))
 			resp.device_caps |= EFA_QUERY_DEVICE_CAPS_RDMA_READ;
 
+		if (EFA_DEV_CAP(dev, RNR_RETRY))
+			resp.device_caps |= EFA_QUERY_DEVICE_CAPS_RNR_RETRY;
+
 		err = ib_copy_to_udata(udata, &resp,
 				       min(sizeof(resp), udata->outlen));
 		if (err) {
@@ -268,7 +271,7 @@ int efa_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr,
 
 #define EFA_QUERY_QP_SUPP_MASK \
 	(IB_QP_STATE | IB_QP_PKEY_INDEX | IB_QP_PORT | \
-	 IB_QP_QKEY | IB_QP_SQ_PSN | IB_QP_CAP)
+	 IB_QP_QKEY | IB_QP_SQ_PSN | IB_QP_CAP | IB_QP_RNR_RETRY)
 
 	if (qp_attr_mask & ~EFA_QUERY_QP_SUPP_MASK) {
 		ibdev_dbg(&dev->ibdev,
@@ -290,6 +293,7 @@ int efa_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr,
 	qp_attr->sq_psn = result.sq_psn;
 	qp_attr->sq_draining = result.sq_draining;
 	qp_attr->port_num = 1;
+	qp_attr->rnr_retry = result.rnr_retry;
 
 	qp_attr->cap.max_send_wr = qp->max_send_wr;
 	qp_attr->cap.max_recv_wr = qp->max_recv_wr;
@@ -776,7 +780,9 @@ static const struct {
 			.valid = 1,
 			.req_param = IB_QP_SQ_PSN,
 			.opt_param = IB_QP_CUR_STATE |
-				     IB_QP_QKEY,
+				     IB_QP_QKEY |
+				     IB_QP_RNR_RETRY,
+
 		}
 	},
 	[IB_QPS_RTS] = {
@@ -856,7 +862,8 @@ static int efa_modify_qp_validate(struct efa_dev *dev, struct efa_qp *qp,
 
 #define EFA_MODIFY_QP_SUPP_MASK \
 	(IB_QP_STATE | IB_QP_CUR_STATE | IB_QP_EN_SQD_ASYNC_NOTIFY | \
-	 IB_QP_PKEY_INDEX | IB_QP_PORT | IB_QP_QKEY | IB_QP_SQ_PSN)
+	 IB_QP_PKEY_INDEX | IB_QP_PORT | IB_QP_QKEY | IB_QP_SQ_PSN | \
+	 IB_QP_RNR_RETRY)
 
 	if (qp_attr_mask & ~EFA_MODIFY_QP_SUPP_MASK) {
 		ibdev_dbg(&dev->ibdev,
@@ -943,6 +950,12 @@ int efa_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr,
 		params.sq_psn = qp_attr->sq_psn;
 	}
 
+	if (qp_attr_mask & IB_QP_RNR_RETRY) {
+		EFA_SET(&params.modify_mask, EFA_ADMIN_MODIFY_QP_CMD_RNR_RETRY,
+			1);
+		params.rnr_retry = qp_attr->rnr_retry;
+	}
+
 	err = efa_com_modify_qp(&dev->edev, &params);
 	if (err)
 		return err;

include/uapi/rdma/efa-abi.h

@@ -105,6 +105,7 @@ struct efa_ibv_create_ah_resp {
 
 enum {
 	EFA_QUERY_DEVICE_CAPS_RDMA_READ = 1 << 0,
+	EFA_QUERY_DEVICE_CAPS_RNR_RETRY = 1 << 1,
 };
 
 struct efa_ibv_ex_query_device_resp {