RDMA/efa: Add data polling capability feature bit

Add feature bit to existing device caps field. EFA supports data polling
of 128 bytes blocks.

The flag indicates that the NIC guarentees that a 128 byte aligned block
is written in order, ie that observing the last 8 bits of the block mean
the prior 127 bytes are also written.

It is useful for "last data polling" acceleration techniques.

Link: https://lore.kernel.org/r/20230219081328.10419-1-mrgolin@amazon.comReviewed-by: Yehuda Yitschak <yehuday@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Yonatan Nachum <ynachum@amazon.com>
Signed-off-by: Michael Margolin <mrgolin@amazon.com>
Acked-by: Gal Pressman <gal.pressman@linux.dev>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/efa/efa_admin_cmds_defs.h

 /* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
 /*
- * Copyright 2018-2021 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2018-2023 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
 #ifndef _EFA_ADMIN_CMDS_H_
@@ -618,7 +618,9 @@ struct efa_admin_feature_device_attr_desc {
 	 *    TX queues
 	 * 1 : rnr_retry - If set, RNR retry is supported on
 	 *    modify QP command
-	 * 31:2 : reserved - MBZ
+	 * 2 : data_polling_128 - If set, 128 bytes data
+	 *    polling is supported
+	 * 31:3 : reserved - MBZ
 	 */
 	u32 device_caps;
 
@@ -991,6 +993,7 @@ 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)
+#define EFA_ADMIN_FEATURE_DEVICE_ATTR_DESC_DATA_POLLING_128_MASK BIT(2)
 
 /* create_eq_cmd */
 #define EFA_ADMIN_CREATE_EQ_CMD_ENTRY_SIZE_WORDS_MASK       GENMASK(4, 0)

drivers/infiniband/hw/efa/efa_verbs.c

 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
 /*
- * Copyright 2018-2022 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2018-2023 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
 #include <linux/dma-buf.h>
@@ -250,6 +250,9 @@ int efa_query_device(struct ib_device *ibdev,
 		if (EFA_DEV_CAP(dev, RNR_RETRY))
 			resp.device_caps |= EFA_QUERY_DEVICE_CAPS_RNR_RETRY;
 
+		if (EFA_DEV_CAP(dev, DATA_POLLING_128))
+			resp.device_caps |= EFA_QUERY_DEVICE_CAPS_DATA_POLLING_128;
+
 		if (dev->neqs)
 			resp.device_caps |= EFA_QUERY_DEVICE_CAPS_CQ_NOTIFICATIONS;
 

include/uapi/rdma/efa-abi.h

 /* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) */
 /*
- * Copyright 2018-2022 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2018-2023 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
 #ifndef EFA_ABI_USER_H
@@ -120,6 +120,7 @@ enum {
 	EFA_QUERY_DEVICE_CAPS_RNR_RETRY = 1 << 1,
 	EFA_QUERY_DEVICE_CAPS_CQ_NOTIFICATIONS = 1 << 2,
 	EFA_QUERY_DEVICE_CAPS_CQ_WITH_SGID     = 1 << 3,
+	EFA_QUERY_DEVICE_CAPS_DATA_POLLING_128 = 1 << 4,
 };
 
 struct efa_ibv_ex_query_device_resp {