1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/mlx5/dmah.c b/drivers/infiniband/hw/mlx5/dmah.c
new file mode 100644
index 000000000000..362a88992ffa
--- /dev/null
+++ b/drivers/infiniband/hw/mlx5/dmah.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION & AFFILIATES. All rights reserved
+ */
+
+#include <rdma/uverbs_std_types.h>
+#include <linux/pci-tph.h>
+#include "dmah.h"
+
+#define UVERBS_MODULE_NAME mlx5_ib
+#include <rdma/uverbs_named_ioctl.h>
+
+static int mlx5_ib_alloc_dmah(struct ib_dmah *ibdmah,
+			      struct uverbs_attr_bundle *attrs)
+{
+	struct mlx5_core_dev *mdev = to_mdev(ibdmah->device)->mdev;
+	struct mlx5_ib_dmah *dmah = to_mdmah(ibdmah);
+	u16 st_bits = BIT(IB_DMAH_CPU_ID_EXISTS) |
+		      BIT(IB_DMAH_MEM_TYPE_EXISTS);
+	int err;
+
+	/* PH is a must for TPH following PCIe spec 6.2-1.0 */
+	if (!(ibdmah->valid_fields & BIT(IB_DMAH_PH_EXISTS)))
+		return -EINVAL;
+
+	/* ST is optional; however, partial data for it is not allowed */
+	if (ibdmah->valid_fields & st_bits) {
+		if ((ibdmah->valid_fields & st_bits) != st_bits)
+			return -EINVAL;
+		err = mlx5_st_alloc_index(mdev, ibdmah->mem_type,
+					  ibdmah->cpu_id, &dmah->st_index);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int mlx5_ib_dealloc_dmah(struct ib_dmah *ibdmah,
+				struct uverbs_attr_bundle *attrs)
+{
+	struct mlx5_ib_dmah *dmah = to_mdmah(ibdmah);
+	struct mlx5_core_dev *mdev = to_mdev(ibdmah->device)->mdev;
+
+	if (ibdmah->valid_fields & BIT(IB_DMAH_CPU_ID_EXISTS))
+		return mlx5_st_dealloc_index(mdev, dmah->st_index);
+
+	return 0;
+}
+
+const struct ib_device_ops mlx5_ib_dev_dmah_ops = {
+	.alloc_dmah = mlx5_ib_alloc_dmah,
+	.dealloc_dmah = mlx5_ib_dealloc_dmah,
+};