RDMA/efa: CQ notifications

This patch adds support for CQ notifications through the standard verbs
api.

In order to achieve that, a new event queue (EQ) object is introduced,
which is in charge of reporting completion events to the driver.  On
driver load, EQs are allocated and their affinity is set to a single
cpu. When a user app creates a CQ with a completion channel, the
completion vector number is converted to a EQ number, which is in charge
of reporting the CQ events.

In addition, the CQ creation admin command now returns an offset for the
CQ doorbell, which is mapped to the userspace provider and is used to arm
the CQ when requested by the user.

The EQs use a single doorbell (located on the registers BAR), which
encodes the EQ number and arm as part of the doorbell value.  The EQs are
polled by the driver on each new EQE, and arm it when the poll is
completed.

Link: https://lore.kernel.org/r/20211003105605.29222-1-galpress@amazon.com
Reviewed-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>

1 files changed, 27 insertions, 8 deletions

diff --git a/drivers/infiniband/hw/efa/efa_com_cmd.c b/drivers/infiniband/hw/efa/efa_com_cmd.c
index f752ef64159c..fb405da4e1db 100644
--- a/drivers/infiniband/hw/efa/efa_com_cmd.c
+++ b/drivers/infiniband/hw/efa/efa_com_cmd.c
@@ -1,17 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
 /*
- * Copyright 2018-2020 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2018-2021 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
 #include "efa_com.h"
 #include "efa_com_cmd.h"
 
-void efa_com_set_dma_addr(dma_addr_t addr, u32 *addr_high, u32 *addr_low)
-{
-	*addr_low = lower_32_bits(addr);
-	*addr_high = upper_32_bits(addr);
-}
-
 int efa_com_create_qp(struct efa_com_dev *edev,
 		      struct efa_com_create_qp_params *params,
 		      struct efa_com_create_qp_result *res)
@@ -157,7 +151,7 @@ int efa_com_create_cq(struct efa_com_dev *edev,
 		      struct efa_com_create_cq_params *params,
 		      struct efa_com_create_cq_result *result)
 {
-	struct efa_admin_create_cq_resp cmd_completion;
+	struct efa_admin_create_cq_resp cmd_completion = {};
 	struct efa_admin_create_cq_cmd create_cmd = {};
 	struct efa_com_admin_queue *aq = &edev->aq;
 	int err;
@@ -169,6 +163,11 @@ int efa_com_create_cq(struct efa_com_dev *edev,
 	create_cmd.cq_depth = params->cq_depth;
 	create_cmd.num_sub_cqs = params->num_sub_cqs;
 	create_cmd.uar = params->uarn;
+	if (params->interrupt_mode_enabled) {
+		EFA_SET(&create_cmd.cq_caps_1,
+			EFA_ADMIN_CREATE_CQ_CMD_INTERRUPT_MODE_ENABLED, 1);
+		create_cmd.eqn = params->eqn;
+	}
 
 	efa_com_set_dma_addr(params->dma_addr,
 			     &create_cmd.cq_ba.mem_addr_high,
@@ -187,6 +186,9 @@ int efa_com_create_cq(struct efa_com_dev *edev,
 
 	result->cq_idx = cmd_completion.cq_idx;
 	result->actual_depth = params->cq_depth;
+	result->db_off = cmd_completion.db_offset;
+	result->db_valid = EFA_GET(&cmd_completion.flags,
+				   EFA_ADMIN_CREATE_CQ_RESP_DB_VALID);
 
 	return 0;
 }
@@ -497,6 +499,23 @@ int efa_com_get_device_attr(struct efa_com_dev *edev,
 	       sizeof(resp.u.network_attr.addr));
 	result->mtu = resp.u.network_attr.mtu;
 
+	if (efa_com_check_supported_feature_id(edev,
+					       EFA_ADMIN_EVENT_QUEUE_ATTR)) {
+		err = efa_com_get_feature(edev, &resp,
+					  EFA_ADMIN_EVENT_QUEUE_ATTR);
+		if (err) {
+			ibdev_err_ratelimited(
+				edev->efa_dev,
+				"Failed to get event queue attributes %d\n",
+				err);
+			return err;
+		}
+
+		result->max_eq = resp.u.event_queue_attr.max_eq;
+		result->max_eq_depth = resp.u.event_queue_attr.max_eq_depth;
+		result->event_bitmask = resp.u.event_queue_attr.event_bitmask;
+	}
+
 	return 0;
 }