Delay mlx5_ib internal resources allocations

From: Leon Romanovsky <leonro@nvidia.com>

Internal mlx5_ib resources are created during mlx5_ib module load. This
behavior is not optimal because it consumes resources that are not
needed when SFs are created. This patch series delays the creation of
mlx5_ib internal resources to the stage when they actually used.
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/mlx5/main.c

@@ -1810,7 +1810,7 @@ static int set_ucontext_resp(struct ib_ucontext *uctx,
 	}
 
 	resp->qp_tab_size = 1 << MLX5_CAP_GEN(dev->mdev, log_max_qp);
-	if (dev->wc_support)
+	if (mlx5_wc_support_get(dev->mdev))
 		resp->bf_reg_size = 1 << MLX5_CAP_GEN(dev->mdev,
 						      log_bf_reg_size);
 	resp->cache_line_size = cache_line_size();
@@ -2337,7 +2337,7 @@ static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vm
 	switch (command) {
 	case MLX5_IB_MMAP_WC_PAGE:
 	case MLX5_IB_MMAP_ALLOC_WC:
-		if (!dev->wc_support)
+		if (!mlx5_wc_support_get(dev->mdev))
 			return -EPERM;
 		fallthrough;
 	case MLX5_IB_MMAP_NC_PAGE:
@@ -3612,7 +3612,7 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_UAR_OBJ_ALLOC)(
 	    alloc_type != MLX5_IB_UAPI_UAR_ALLOC_TYPE_NC)
 		return -EOPNOTSUPP;
 
-	if (!to_mdev(c->ibucontext.device)->wc_support &&
+	if (!mlx5_wc_support_get(to_mdev(c->ibucontext.device)->mdev) &&
 	    alloc_type == MLX5_IB_UAPI_UAR_ALLOC_TYPE_BF)
 		return -EOPNOTSUPP;
 
@@ -3766,18 +3766,6 @@ static int mlx5_ib_stage_init_init(struct mlx5_ib_dev *dev)
 	return err;
 }
 
-static int mlx5_ib_enable_driver(struct ib_device *dev)
-{
-	struct mlx5_ib_dev *mdev = to_mdev(dev);
-	int ret;
-
-	ret = mlx5_ib_test_wc(mdev);
-	mlx5_ib_dbg(mdev, "Write-Combining %s",
-		    mdev->wc_support ? "supported" : "not supported");
-
-	return ret;
-}
-
 static const struct ib_device_ops mlx5_ib_dev_ops = {
 	.owner = THIS_MODULE,
 	.driver_id = RDMA_DRIVER_MLX5,
@@ -3808,7 +3796,6 @@ static const struct ib_device_ops mlx5_ib_dev_ops = {
 	.drain_rq = mlx5_ib_drain_rq,
 	.drain_sq = mlx5_ib_drain_sq,
 	.device_group = &mlx5_attr_group,
-	.enable_driver = mlx5_ib_enable_driver,
 	.get_dev_fw_str = get_dev_fw_str,
 	.get_dma_mr = mlx5_ib_get_dma_mr,
 	.get_link_layer = mlx5_ib_port_link_layer,

drivers/infiniband/hw/mlx5/mem.c

@@ -30,10 +30,8 @@
  * SOFTWARE.
  */
 
-#include <linux/io.h>
 #include <rdma/ib_umem_odp.h>
 #include "mlx5_ib.h"
-#include <linux/jiffies.h>
 
 /*
  * Fill in a physical address list. ib_umem_num_dma_blocks() entries will be
@@ -95,199 +93,3 @@ unsigned long __mlx5_umem_find_best_quantized_pgoff(
 		return 0;
 	return page_size;
 }
-
-#define WR_ID_BF 0xBF
-#define WR_ID_END 0xBAD
-#define TEST_WC_NUM_WQES 255
-#define TEST_WC_POLLING_MAX_TIME_JIFFIES msecs_to_jiffies(100)
-static int post_send_nop(struct mlx5_ib_dev *dev, struct ib_qp *ibqp, u64 wr_id,
-			 bool signaled)
-{
-	struct mlx5_ib_qp *qp = to_mqp(ibqp);
-	struct mlx5_wqe_ctrl_seg *ctrl;
-	struct mlx5_bf *bf = &qp->bf;
-	__be32 mmio_wqe[16] = {};
-	unsigned long flags;
-	unsigned int idx;
-
-	if (unlikely(dev->mdev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR))
-		return -EIO;
-
-	spin_lock_irqsave(&qp->sq.lock, flags);
-
-	idx = qp->sq.cur_post & (qp->sq.wqe_cnt - 1);
-	ctrl = mlx5_frag_buf_get_wqe(&qp->sq.fbc, idx);
-
-	memset(ctrl, 0, sizeof(struct mlx5_wqe_ctrl_seg));
-	ctrl->fm_ce_se = signaled ? MLX5_WQE_CTRL_CQ_UPDATE : 0;
-	ctrl->opmod_idx_opcode =
-		cpu_to_be32(((u32)(qp->sq.cur_post) << 8) | MLX5_OPCODE_NOP);
-	ctrl->qpn_ds = cpu_to_be32((sizeof(struct mlx5_wqe_ctrl_seg) / 16) |
-				   (qp->trans_qp.base.mqp.qpn << 8));
-
-	qp->sq.wrid[idx] = wr_id;
-	qp->sq.w_list[idx].opcode = MLX5_OPCODE_NOP;
-	qp->sq.wqe_head[idx] = qp->sq.head + 1;
-	qp->sq.cur_post += DIV_ROUND_UP(sizeof(struct mlx5_wqe_ctrl_seg),
-					MLX5_SEND_WQE_BB);
-	qp->sq.w_list[idx].next = qp->sq.cur_post;
-	qp->sq.head++;
-
-	memcpy(mmio_wqe, ctrl, sizeof(*ctrl));
-	((struct mlx5_wqe_ctrl_seg *)&mmio_wqe)->fm_ce_se |=
-		MLX5_WQE_CTRL_CQ_UPDATE;
-
-	/* Make sure that descriptors are written before
-	 * updating doorbell record and ringing the doorbell
-	 */
-	wmb();
-
-	qp->db.db[MLX5_SND_DBR] = cpu_to_be32(qp->sq.cur_post);
-
-	/* Make sure doorbell record is visible to the HCA before
-	 * we hit doorbell
-	 */
-	wmb();
-	__iowrite64_copy(bf->bfreg->map + bf->offset, mmio_wqe,
-			 sizeof(mmio_wqe) / 8);
-
-	bf->offset ^= bf->buf_size;
-
-	spin_unlock_irqrestore(&qp->sq.lock, flags);
-
-	return 0;
-}
-
-static int test_wc_poll_cq_result(struct mlx5_ib_dev *dev, struct ib_cq *cq)
-{
-	int ret;
-	struct ib_wc wc = {};
-	unsigned long end = jiffies + TEST_WC_POLLING_MAX_TIME_JIFFIES;
-
-	do {
-		ret = ib_poll_cq(cq, 1, &wc);
-		if (ret < 0 || wc.status)
-			return ret < 0 ? ret : -EINVAL;
-		if (ret)
-			break;
-	} while (!time_after(jiffies, end));
-
-	if (!ret)
-		return -ETIMEDOUT;
-
-	if (wc.wr_id != WR_ID_BF)
-		ret = 0;
-
-	return ret;
-}
-
-static int test_wc_do_send(struct mlx5_ib_dev *dev, struct ib_qp *qp)
-{
-	int err, i;
-
-	for (i = 0; i < TEST_WC_NUM_WQES; i++) {
-		err = post_send_nop(dev, qp, WR_ID_BF, false);
-		if (err)
-			return err;
-	}
-
-	return post_send_nop(dev, qp, WR_ID_END, true);
-}
-
-int mlx5_ib_test_wc(struct mlx5_ib_dev *dev)
-{
-	struct ib_cq_init_attr cq_attr = { .cqe = TEST_WC_NUM_WQES + 1 };
-	int port_type_cap = MLX5_CAP_GEN(dev->mdev, port_type);
-	struct ib_qp_init_attr qp_init_attr = {
-		.cap = { .max_send_wr = TEST_WC_NUM_WQES },
-		.qp_type = IB_QPT_UD,
-		.sq_sig_type = IB_SIGNAL_REQ_WR,
-		.create_flags = MLX5_IB_QP_CREATE_WC_TEST,
-	};
-	struct ib_qp_attr qp_attr = { .port_num = 1 };
-	struct ib_device *ibdev = &dev->ib_dev;
-	struct ib_qp *qp;
-	struct ib_cq *cq;
-	struct ib_pd *pd;
-	int ret;
-
-	if (!MLX5_CAP_GEN(dev->mdev, bf))
-		return 0;
-
-	if (!dev->mdev->roce.roce_en &&
-	    port_type_cap == MLX5_CAP_PORT_TYPE_ETH) {
-		if (mlx5_core_is_pf(dev->mdev))
-			dev->wc_support = arch_can_pci_mmap_wc();
-		return 0;
-	}
-
-	ret = mlx5_alloc_bfreg(dev->mdev, &dev->wc_bfreg, true, false);
-	if (ret)
-		goto print_err;
-
-	if (!dev->wc_bfreg.wc)
-		goto out1;
-
-	pd = ib_alloc_pd(ibdev, 0);
-	if (IS_ERR(pd)) {
-		ret = PTR_ERR(pd);
-		goto out1;
-	}
-
-	cq = ib_create_cq(ibdev, NULL, NULL, NULL, &cq_attr);
-	if (IS_ERR(cq)) {
-		ret = PTR_ERR(cq);
-		goto out2;
-	}
-
-	qp_init_attr.recv_cq = cq;
-	qp_init_attr.send_cq = cq;
-	qp = ib_create_qp(pd, &qp_init_attr);
-	if (IS_ERR(qp)) {
-		ret = PTR_ERR(qp);
-		goto out3;
-	}
-
-	qp_attr.qp_state = IB_QPS_INIT;
-	ret = ib_modify_qp(qp, &qp_attr,
-			   IB_QP_STATE | IB_QP_PORT | IB_QP_PKEY_INDEX |
-				   IB_QP_QKEY);
-	if (ret)
-		goto out4;
-
-	qp_attr.qp_state = IB_QPS_RTR;
-	ret = ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
-	if (ret)
-		goto out4;
-
-	qp_attr.qp_state = IB_QPS_RTS;
-	ret = ib_modify_qp(qp, &qp_attr, IB_QP_STATE | IB_QP_SQ_PSN);
-	if (ret)
-		goto out4;
-
-	ret = test_wc_do_send(dev, qp);
-	if (ret < 0)
-		goto out4;
-
-	ret = test_wc_poll_cq_result(dev, cq);
-	if (ret > 0) {
-		dev->wc_support = true;
-		ret = 0;
-	}
-
-out4:
-	ib_destroy_qp(qp);
-out3:
-	ib_destroy_cq(cq);
-out2:
-	ib_dealloc_pd(pd);
-out1:
-	mlx5_free_bfreg(dev->mdev, &dev->wc_bfreg);
-print_err:
-	if (ret)
-		mlx5_ib_err(
-			dev,
-			"Error %d while trying to test write-combining support\n",
-			ret);
-	return ret;
-}

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -341,7 +341,6 @@ struct mlx5_ib_flow_db {
  * rely on the range reserved for that use in the ib_qp_create_flags enum.
  */
 #define MLX5_IB_QP_CREATE_SQPN_QP1	IB_QP_CREATE_RESERVED_START
-#define MLX5_IB_QP_CREATE_WC_TEST	(IB_QP_CREATE_RESERVED_START << 1)
 
 struct wr_list {
 	u16	opcode;
@@ -1123,7 +1122,6 @@ struct mlx5_ib_dev {
 	u8				ib_active:1;
 	u8				is_rep:1;
 	u8				lag_active:1;
-	u8				wc_support:1;
 	u8				fill_delay;
 	struct umr_common		umrc;
 	/* sync used page count stats
@@ -1149,7 +1147,6 @@ struct mlx5_ib_dev {
 	/* Array with num_ports elements */
 	struct mlx5_ib_port	*port;
 	struct mlx5_sq_bfreg	bfreg;
-	struct mlx5_sq_bfreg	wc_bfreg;
 	struct mlx5_sq_bfreg	fp_bfreg;
 	struct mlx5_ib_delay_drop	delay_drop;
 	const struct mlx5_ib_profile	*profile;

drivers/infiniband/hw/mlx5/qp.c

@@ -1107,8 +1107,6 @@ static int _create_kernel_qp(struct mlx5_ib_dev *dev,
 
 	if (init_attr->qp_type == MLX5_IB_QPT_REG_UMR)
 		qp->bf.bfreg = &dev->fp_bfreg;
-	else if (qp->flags & MLX5_IB_QP_CREATE_WC_TEST)
-		qp->bf.bfreg = &dev->wc_bfreg;
 	else
 		qp->bf.bfreg = &dev->bfreg;
 
@@ -2959,14 +2957,6 @@ static void process_create_flag(struct mlx5_ib_dev *dev, int *flags, int flag,
 		return;
 	}
 
-	if (flag == MLX5_IB_QP_CREATE_WC_TEST) {
-		/*
-		 * Special case, if condition didn't meet, it won't be error,
-		 * just different in-kernel flow.
-		 */
-		*flags &= ~MLX5_IB_QP_CREATE_WC_TEST;
-		return;
-	}
 	mlx5_ib_dbg(dev, "Verbs create QP flag 0x%X is not supported\n", flag);
 }
 
@@ -3027,8 +3017,6 @@ static int process_create_flags(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 			    IB_QP_CREATE_PCI_WRITE_END_PADDING,
 			    MLX5_CAP_GEN(mdev, end_pad), qp);
 
-	process_create_flag(dev, &create_flags, MLX5_IB_QP_CREATE_WC_TEST,
-			    qp_type != MLX5_IB_QPT_REG_UMR, qp);
 	process_create_flag(dev, &create_flags, MLX5_IB_QP_CREATE_SQPN_QP1,
 			    true, qp);
 
@@ -4609,10 +4597,6 @@ static bool mlx5_ib_modify_qp_allowed(struct mlx5_ib_dev *dev,
 	if (qp->type == IB_QPT_RAW_PACKET || qp->type == MLX5_IB_QPT_REG_UMR)
 		return true;
 
-	/* Internal QP used for wc testing, with NOPs in wq */
-	if (qp->flags & MLX5_IB_QP_CREATE_WC_TEST)
-		return true;
-
 	return false;
 }
 

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -17,7 +17,7 @@ mlx5_core-y :=	main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
 		fs_counters.o fs_ft_pool.o rl.o lag/debugfs.o lag/lag.o dev.o events.o wq.o lib/gid.o \
 		lib/devcom.o lib/pci_vsc.o lib/dm.o lib/fs_ttc.o diag/fs_tracepoint.o \
 		diag/fw_tracer.o diag/crdump.o devlink.o diag/rsc_dump.o diag/reporter_vnic.o \
-		fw_reset.o qos.o lib/tout.o lib/aso.o
+		fw_reset.o qos.o lib/tout.o lib/aso.o wc.o
 
 #
 # Netdev basic

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1819,6 +1819,7 @@ int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx)
 	mutex_init(&dev->intf_state_mutex);
 	lockdep_set_class(&dev->intf_state_mutex, &dev->lock_key);
 	mutex_init(&dev->mlx5e_res.uplink_netdev_lock);
+	mutex_init(&dev->wc_state_lock);
 
 	mutex_init(&priv->bfregs.reg_head.lock);
 	mutex_init(&priv->bfregs.wc_head.lock);
@@ -1916,6 +1917,7 @@ void mlx5_mdev_uninit(struct mlx5_core_dev *dev)
 	mutex_destroy(&priv->alloc_mutex);
 	mutex_destroy(&priv->bfregs.wc_head.lock);
 	mutex_destroy(&priv->bfregs.reg_head.lock);
+	mutex_destroy(&dev->wc_state_lock);
 	mutex_destroy(&dev->mlx5e_res.uplink_netdev_lock);
 	mutex_destroy(&dev->intf_state_mutex);
 	lockdep_unregister_key(&dev->lock_key);

drivers/net/ethernet/mellanox/mlx5/core/wc.c

+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+// Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
+#include <linux/io.h>
+#include <linux/mlx5/transobj.h>
+#include "lib/clock.h"
+#include "mlx5_core.h"
+#include "wq.h"
+
+#define TEST_WC_NUM_WQES 255
+#define TEST_WC_LOG_CQ_SZ (order_base_2(TEST_WC_NUM_WQES))
+#define TEST_WC_SQ_LOG_WQ_SZ TEST_WC_LOG_CQ_SZ
+#define TEST_WC_POLLING_MAX_TIME_JIFFIES msecs_to_jiffies(100)
+
+struct mlx5_wc_cq {
+	/* data path - accessed per cqe */
+	struct mlx5_cqwq wq;
+
+	/* data path - accessed per napi poll */
+	struct mlx5_core_cq mcq;
+
+	/* control */
+	struct mlx5_core_dev *mdev;
+	struct mlx5_wq_ctrl wq_ctrl;
+};
+
+struct mlx5_wc_sq {
+	/* data path */
+	u16 cc;
+	u16 pc;
+
+	/* read only */
+	struct mlx5_wq_cyc wq;
+	u32 sqn;
+
+	/* control path */
+	struct mlx5_wq_ctrl wq_ctrl;
+
+	struct mlx5_wc_cq cq;
+	struct mlx5_sq_bfreg bfreg;
+};
+
+static int mlx5_wc_create_cqwq(struct mlx5_core_dev *mdev, void *cqc,
+			       struct mlx5_wc_cq *cq)
+{
+	struct mlx5_core_cq *mcq = &cq->mcq;
+	struct mlx5_wq_param param = {};
+	int err;
+	u32 i;
+
+	err = mlx5_cqwq_create(mdev, &param, cqc, &cq->wq, &cq->wq_ctrl);
+	if (err)
+		return err;
+
+	mcq->cqe_sz     = 64;
+	mcq->set_ci_db  = cq->wq_ctrl.db.db;
+	mcq->arm_db     = cq->wq_ctrl.db.db + 1;
+
+	for (i = 0; i < mlx5_cqwq_get_size(&cq->wq); i++) {
+		struct mlx5_cqe64 *cqe = mlx5_cqwq_get_wqe(&cq->wq, i);
+
+		cqe->op_own = 0xf1;
+	}
+
+	cq->mdev = mdev;
+
+	return 0;
+}
+
+static int create_wc_cq(struct mlx5_wc_cq *cq, void *cqc_data)
+{
+	u32 out[MLX5_ST_SZ_DW(create_cq_out)];
+	struct mlx5_core_dev *mdev = cq->mdev;
+	struct mlx5_core_cq *mcq = &cq->mcq;
+	int err, inlen, eqn;
+	void *in, *cqc;
+
+	err = mlx5_comp_eqn_get(mdev, 0, &eqn);
+	if (err)
+		return err;
+
+	inlen = MLX5_ST_SZ_BYTES(create_cq_in) +
+		sizeof(u64) * cq->wq_ctrl.buf.npages;
+	in = kvzalloc(inlen, GFP_KERNEL);
+	if (!in)
+		return -ENOMEM;
+
+	cqc = MLX5_ADDR_OF(create_cq_in, in, cq_context);
+
+	memcpy(cqc, cqc_data, MLX5_ST_SZ_BYTES(cqc));
+
+	mlx5_fill_page_frag_array(&cq->wq_ctrl.buf,
+				  (__be64 *)MLX5_ADDR_OF(create_cq_in, in, pas));
+
+	MLX5_SET(cqc,   cqc, cq_period_mode, MLX5_CQ_PERIOD_MODE_START_FROM_EQE);
+	MLX5_SET(cqc,   cqc, c_eqn_or_apu_element, eqn);
+	MLX5_SET(cqc,   cqc, uar_page,      mdev->priv.uar->index);
+	MLX5_SET(cqc,   cqc, log_page_size, cq->wq_ctrl.buf.page_shift -
+					    MLX5_ADAPTER_PAGE_SHIFT);
+	MLX5_SET64(cqc, cqc, dbr_addr,      cq->wq_ctrl.db.dma);
+
+	err = mlx5_core_create_cq(mdev, mcq, in, inlen, out, sizeof(out));
+
+	kvfree(in);
+
+	return err;
+}
+
+static int mlx5_wc_create_cq(struct mlx5_core_dev *mdev, struct mlx5_wc_cq *cq)
+{
+	void *cqc;
+	int err;
+
+	cqc = kvzalloc(MLX5_ST_SZ_BYTES(cqc), GFP_KERNEL);
+	if (!cqc)
+		return -ENOMEM;
+
+	MLX5_SET(cqc, cqc, log_cq_size, TEST_WC_LOG_CQ_SZ);
+	MLX5_SET(cqc, cqc, uar_page, mdev->priv.uar->index);
+	if (MLX5_CAP_GEN(mdev, cqe_128_always) && cache_line_size() >= 128)
+		MLX5_SET(cqc, cqc, cqe_sz, CQE_STRIDE_128_PAD);
+
+	err = mlx5_wc_create_cqwq(mdev, cqc, cq);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to create wc cq wq, err=%d\n", err);
+		goto err_create_cqwq;
+	}
+
+	err = create_wc_cq(cq, cqc);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to create wc cq, err=%d\n", err);
+		goto err_create_cq;
+	}
+
+	kvfree(cqc);
+	return 0;
+
+err_create_cq:
+	mlx5_wq_destroy(&cq->wq_ctrl);
+err_create_cqwq:
+	kvfree(cqc);
+	return err;
+}
+
+static void mlx5_wc_destroy_cq(struct mlx5_wc_cq *cq)
+{
+	mlx5_core_destroy_cq(cq->mdev, &cq->mcq);
+	mlx5_wq_destroy(&cq->wq_ctrl);
+}
+
+static int create_wc_sq(struct mlx5_core_dev *mdev, void *sqc_data,
+			struct mlx5_wc_sq *sq)
+{
+	void *in, *sqc, *wq;
+	int inlen, err;
+	u8 ts_format;
+
+	inlen = MLX5_ST_SZ_BYTES(create_sq_in) +
+		sizeof(u64) * sq->wq_ctrl.buf.npages;
+	in = kvzalloc(inlen, GFP_KERNEL);
+	if (!in)
+		return -ENOMEM;
+
+	sqc = MLX5_ADDR_OF(create_sq_in, in, ctx);
+	wq = MLX5_ADDR_OF(sqc, sqc, wq);
+
+	memcpy(sqc, sqc_data, MLX5_ST_SZ_BYTES(sqc));
+	MLX5_SET(sqc,  sqc, cqn, sq->cq.mcq.cqn);
+
+	MLX5_SET(sqc,  sqc, state, MLX5_SQC_STATE_RST);
+	MLX5_SET(sqc,  sqc, flush_in_error_en, 1);
+
+	ts_format = mlx5_is_real_time_sq(mdev) ?
+			MLX5_TIMESTAMP_FORMAT_REAL_TIME :
+			MLX5_TIMESTAMP_FORMAT_FREE_RUNNING;
+	MLX5_SET(sqc, sqc, ts_format, ts_format);
+
+	MLX5_SET(wq,   wq, wq_type,       MLX5_WQ_TYPE_CYCLIC);
+	MLX5_SET(wq,   wq, uar_page,      sq->bfreg.index);
+	MLX5_SET(wq,   wq, log_wq_pg_sz,  sq->wq_ctrl.buf.page_shift -
+					  MLX5_ADAPTER_PAGE_SHIFT);
+	MLX5_SET64(wq, wq, dbr_addr,      sq->wq_ctrl.db.dma);
+
+	mlx5_fill_page_frag_array(&sq->wq_ctrl.buf,
+				  (__be64 *)MLX5_ADDR_OF(wq, wq, pas));
+
+	err = mlx5_core_create_sq(mdev, in, inlen, &sq->sqn);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to create wc sq, err=%d\n", err);
+		goto err_create_sq;
+	}
+
+	memset(in, 0,  MLX5_ST_SZ_BYTES(modify_sq_in));
+	MLX5_SET(modify_sq_in, in, sq_state, MLX5_SQC_STATE_RST);
+	sqc = MLX5_ADDR_OF(modify_sq_in, in, ctx);
+	MLX5_SET(sqc, sqc, state, MLX5_SQC_STATE_RDY);
+
+	err = mlx5_core_modify_sq(mdev, sq->sqn, in);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to set wc sq(sqn=0x%x) ready, err=%d\n",
+			      sq->sqn, err);
+		goto err_modify_sq;
+	}
+
+	kvfree(in);
+	return 0;
+
+err_modify_sq:
+	mlx5_core_destroy_sq(mdev, sq->sqn);
+err_create_sq:
+	kvfree(in);
+	return err;
+}
+
+static int mlx5_wc_create_sq(struct mlx5_core_dev *mdev, struct mlx5_wc_sq *sq)
+{
+	struct mlx5_wq_param param = {};
+	void *sqc_data, *wq;
+	int err;
+
+	sqc_data = kvzalloc(MLX5_ST_SZ_BYTES(sqc), GFP_KERNEL);
+	if (!sqc_data)
+		return -ENOMEM;
+
+	wq = MLX5_ADDR_OF(sqc, sqc_data, wq);
+	MLX5_SET(wq, wq, log_wq_stride, ilog2(MLX5_SEND_WQE_BB));
+	MLX5_SET(wq, wq, pd, mdev->mlx5e_res.hw_objs.pdn);
+	MLX5_SET(wq, wq, log_wq_sz, TEST_WC_SQ_LOG_WQ_SZ);
+
+	err = mlx5_wq_cyc_create(mdev, &param, wq, &sq->wq, &sq->wq_ctrl);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to create wc sq wq, err=%d\n", err);
+		goto err_create_wq_cyc;
+	}
+
+	err = create_wc_sq(mdev, sqc_data, sq);
+	if (err)
+		goto err_create_sq;
+
+	mlx5_core_dbg(mdev, "wc sq->sqn = 0x%x created\n", sq->sqn);
+
+	kvfree(sqc_data);
+	return 0;
+
+err_create_sq:
+	mlx5_wq_destroy(&sq->wq_ctrl);
+err_create_wq_cyc:
+	kvfree(sqc_data);
+	return err;
+}
+
+static void mlx5_wc_destroy_sq(struct mlx5_wc_sq *sq)
+{
+	mlx5_core_destroy_sq(sq->cq.mdev, sq->sqn);
+	mlx5_wq_destroy(&sq->wq_ctrl);
+}
+
+static void mlx5_wc_post_nop(struct mlx5_wc_sq *sq, bool signaled)
+{
+	int buf_size = (1 << MLX5_CAP_GEN(sq->cq.mdev, log_bf_reg_size)) / 2;
+	struct mlx5_wqe_ctrl_seg *ctrl;
+	__be32 mmio_wqe[16] = {};
+	u16 pi;
+
+	pi = mlx5_wq_cyc_ctr2ix(&sq->wq, sq->pc);
+	ctrl = mlx5_wq_cyc_get_wqe(&sq->wq, pi);
+	memset(ctrl, 0, sizeof(*ctrl));
+	ctrl->opmod_idx_opcode =
+		cpu_to_be32((sq->pc << MLX5_WQE_CTRL_WQE_INDEX_SHIFT) | MLX5_OPCODE_NOP);
+	ctrl->qpn_ds =
+		cpu_to_be32((sq->sqn << MLX5_WQE_CTRL_QPN_SHIFT) |
+			    DIV_ROUND_UP(sizeof(struct mlx5_wqe_ctrl_seg), MLX5_SEND_WQE_DS));
+	if (signaled)
+		ctrl->fm_ce_se |= MLX5_WQE_CTRL_CQ_UPDATE;
+
+	memcpy(mmio_wqe, ctrl, sizeof(*ctrl));
+	((struct mlx5_wqe_ctrl_seg *)&mmio_wqe)->fm_ce_se |=
+		MLX5_WQE_CTRL_CQ_UPDATE;
+
+	/* ensure wqe is visible to device before updating doorbell record */
+	dma_wmb();
+
+	sq->pc++;
+	sq->wq.db[MLX5_SND_DBR] = cpu_to_be32(sq->pc);
+
+	/* ensure doorbell record is visible to device before ringing the
+	 * doorbell
+	 */
+	wmb();
+
+	__iowrite64_copy(sq->bfreg.map + sq->bfreg.offset, mmio_wqe,
+			 sizeof(mmio_wqe) / 8);
+
+	sq->bfreg.offset ^= buf_size;
+}
+
+static int mlx5_wc_poll_cq(struct mlx5_wc_sq *sq)
+{
+	struct mlx5_wc_cq *cq = &sq->cq;
+	struct mlx5_cqe64 *cqe;
+
+	cqe = mlx5_cqwq_get_cqe(&cq->wq);
+	if (!cqe)
+		return -ETIMEDOUT;
+
+	/* sq->cc must be updated only after mlx5_cqwq_update_db_record(),
+	 * otherwise a cq overrun may occur
+	 */
+	mlx5_cqwq_pop(&cq->wq);
+
+	if (get_cqe_opcode(cqe) == MLX5_CQE_REQ) {
+		int wqe_counter = be16_to_cpu(cqe->wqe_counter);
+		struct mlx5_core_dev *mdev = cq->mdev;
+
+		if (wqe_counter == TEST_WC_NUM_WQES - 1)
+			mdev->wc_state = MLX5_WC_STATE_UNSUPPORTED;
+		else
+			mdev->wc_state = MLX5_WC_STATE_SUPPORTED;
+
+		mlx5_core_dbg(mdev, "wc wqe_counter = 0x%x\n", wqe_counter);
+	}
+
+	mlx5_cqwq_update_db_record(&cq->wq);
+
+	/* ensure cq space is freed before enabling more cqes */
+	wmb();
+
+	sq->cc++;
+
+	return 0;
+}
+
+static void mlx5_core_test_wc(struct mlx5_core_dev *mdev)
+{
+	unsigned long expires;
+	struct mlx5_wc_sq *sq;
+	int i, err;
+
+	if (mdev->wc_state != MLX5_WC_STATE_UNINITIALIZED)
+		return;
+
+	sq = kzalloc(sizeof(*sq), GFP_KERNEL);
+	if (!sq)
+		return;
+
+	err = mlx5_alloc_bfreg(mdev, &sq->bfreg, true, false);
+	if (err) {
+		mlx5_core_err(mdev, "Failed to alloc bfreg for wc, err=%d\n", err);
+		goto err_alloc_bfreg;
+	}
+
+	err = mlx5_wc_create_cq(mdev, &sq->cq);
+	if (err)
+		goto err_create_cq;
+
+	err = mlx5_wc_create_sq(mdev, sq);
+	if (err)
+		goto err_create_sq;
+
+	for (i = 0; i < TEST_WC_NUM_WQES - 1; i++)
+		mlx5_wc_post_nop(sq, false);
+
+	mlx5_wc_post_nop(sq, true);
+
+	expires = jiffies + TEST_WC_POLLING_MAX_TIME_JIFFIES;
+	do {
+		err = mlx5_wc_poll_cq(sq);
+		if (err)
+			usleep_range(2, 10);
+	} while (mdev->wc_state == MLX5_WC_STATE_UNINITIALIZED &&
+		 time_is_after_jiffies(expires));
+
+	mlx5_wc_destroy_sq(sq);
+
+err_create_sq:
+	mlx5_wc_destroy_cq(&sq->cq);
+err_create_cq:
+	mlx5_free_bfreg(mdev, &sq->bfreg);
+err_alloc_bfreg:
+	kfree(sq);
+}
+
+bool mlx5_wc_support_get(struct mlx5_core_dev *mdev)
+{
+	struct mlx5_core_dev *parent = NULL;
+
+	if (!MLX5_CAP_GEN(mdev, bf)) {
+		mlx5_core_dbg(mdev, "BlueFlame not supported\n");
+		goto out;
+	}
+
+	if (!MLX5_CAP_GEN(mdev, log_max_sq)) {
+		mlx5_core_dbg(mdev, "SQ not supported\n");
+		goto out;
+	}
+
+	if (mdev->wc_state != MLX5_WC_STATE_UNINITIALIZED)
+		/* No need to lock anything as we perform WC test only
+		 * once for whole device and was already done.
+		 */
+		goto out;
+
+	mutex_lock(&mdev->wc_state_lock);
+
+	if (mdev->wc_state != MLX5_WC_STATE_UNINITIALIZED)
+		goto unlock;
+
+#ifdef CONFIG_MLX5_SF
+	if (mlx5_core_is_sf(mdev))
+		parent = mdev->priv.parent_mdev;
+#endif
+
+	if (parent) {
+		mutex_lock(&parent->wc_state_lock);
+
+		mlx5_core_test_wc(parent);
+
+		mlx5_core_dbg(mdev, "parent set wc_state=%d\n",
+			      parent->wc_state);
+		mdev->wc_state = parent->wc_state;
+
+		mutex_unlock(&parent->wc_state_lock);
+	}
+
+	mlx5_core_test_wc(mdev);
+
+unlock:
+	mutex_unlock(&mdev->wc_state_lock);
+out:
+	mlx5_core_dbg(mdev, "wc_state=%d\n", mdev->wc_state);
+
+	return mdev->wc_state == MLX5_WC_STATE_SUPPORTED;
+}
+EXPORT_SYMBOL(mlx5_wc_support_get);

include/linux/mlx5/driver.h

@@ -766,6 +766,12 @@ struct mlx5_hca_cap {
 	u32 max[MLX5_UN_SZ_DW(hca_cap_union)];
 };
 
+enum mlx5_wc_state {
+	MLX5_WC_STATE_UNINITIALIZED,
+	MLX5_WC_STATE_UNSUPPORTED,
+	MLX5_WC_STATE_SUPPORTED,
+};
+
 struct mlx5_core_dev {
 	struct device *device;
 	enum mlx5_coredev_type coredev_type;
@@ -824,6 +830,9 @@ struct mlx5_core_dev {
 #endif
 	u64 num_ipsec_offloads;
 	struct mlx5_sd          *sd;
+	enum mlx5_wc_state wc_state;
+	/* sync write combining state */
+	struct mutex wc_state_lock;
 };
 
 struct mlx5_db {
@@ -1375,4 +1384,6 @@ static inline bool mlx5_is_macsec_roce_supported(struct mlx5_core_dev *mdev)
 enum {
 	MLX5_OCTWORD = 16,
 };
+
+bool mlx5_wc_support_get(struct mlx5_core_dev *mdev);
 #endif /* MLX5_DRIVER_H */