net/mlx5: Add wrappers for HyperV PCIe operations

Add wrapper functions for HyperV PCIe read / write /
block_invalidate_register operations.  This will be used as an
infrastructure in the downstream patch for software communication.

This will be enabled by default if CONFIG_PCI_HYPERV_INTERFACE is set.
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -45,6 +45,7 @@ mlx5_core-$(CONFIG_MLX5_ESWITCH)   += eswitch.o eswitch_offloads.o eswitch_offlo
 mlx5_core-$(CONFIG_MLX5_MPFS)      += lib/mpfs.o
 mlx5_core-$(CONFIG_VXLAN)          += lib/vxlan.o
 mlx5_core-$(CONFIG_PTP_1588_CLOCK) += lib/clock.o
+mlx5_core-$(CONFIG_PCI_HYPERV_INTERFACE) += lib/hv.o
 
 #
 # Ipoib netdev

drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c

+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+// Copyright (c) 2018 Mellanox Technologies
+
+#include <linux/hyperv.h>
+#include "mlx5_core.h"
+#include "lib/hv.h"
+
+static int mlx5_hv_config_common(struct mlx5_core_dev *dev, void *buf, int len,
+				 int offset, bool read)
+{
+	int rc = -EOPNOTSUPP;
+	int bytes_returned;
+	int block_id;
+
+	if (offset % HV_CONFIG_BLOCK_SIZE_MAX || len % HV_CONFIG_BLOCK_SIZE_MAX)
+		return -EINVAL;
+
+	block_id = offset / HV_CONFIG_BLOCK_SIZE_MAX;
+
+	rc = read ?
+	     hyperv_read_cfg_blk(dev->pdev, buf,
+				 HV_CONFIG_BLOCK_SIZE_MAX, block_id,
+				 &bytes_returned) :
+	     hyperv_write_cfg_blk(dev->pdev, buf,
+				  HV_CONFIG_BLOCK_SIZE_MAX, block_id);
+
+	/* Make sure len bytes were read successfully  */
+	if (read)
+		rc |= !(len == bytes_returned);
+
+	if (rc) {
+		mlx5_core_err(dev, "Failed to %s hv config, err = %d, len = %d, offset = %d\n",
+			      read ? "read" : "write", rc, len,
+			      offset);
+		return rc;
+	}
+
+	return 0;
+}
+
+int mlx5_hv_read_config(struct mlx5_core_dev *dev, void *buf, int len,
+			int offset)
+{
+	return mlx5_hv_config_common(dev, buf, len, offset, true);
+}
+
+int mlx5_hv_write_config(struct mlx5_core_dev *dev, void *buf, int len,
+			 int offset)
+{
+	return mlx5_hv_config_common(dev, buf, len, offset, false);
+}
+
+int mlx5_hv_register_invalidate(struct mlx5_core_dev *dev, void *context,
+				void (*block_invalidate)(void *context,
+							 u64 block_mask))
+{
+	return hyperv_reg_block_invalidate(dev->pdev, context,
+					   block_invalidate);
+}
+
+void mlx5_hv_unregister_invalidate(struct mlx5_core_dev *dev)
+{
+	hyperv_reg_block_invalidate(dev->pdev, NULL, NULL);
+}

drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h

+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/* Copyright (c) 2019 Mellanox Technologies. */
+
+#ifndef __LIB_HV_H__
+#define __LIB_HV_H__
+
+#if IS_ENABLED(CONFIG_PCI_HYPERV_INTERFACE)
+
+#include <linux/hyperv.h>
+#include <linux/mlx5/driver.h>
+
+int mlx5_hv_read_config(struct mlx5_core_dev *dev, void *buf, int len,
+			int offset);
+int mlx5_hv_write_config(struct mlx5_core_dev *dev, void *buf, int len,
+			 int offset);
+int mlx5_hv_register_invalidate(struct mlx5_core_dev *dev, void *context,
+				void (*block_invalidate)(void *context,
+							 u64 block_mask));
+void mlx5_hv_unregister_invalidate(struct mlx5_core_dev *dev);
+#endif
+
+#endif /* __LIB_HV_H__ */