RDMA/bnxt_re: Support doorbell extensions

Some applications may need multiple doorbells to support parallel
processing of threads that each operate on a group of resources.

The following uapi methods have been implemented in this patch.

- BNXT_RE_METHOD_DBR_ALLOC:
  This will allow the appliation to create extra doorbell regions
  and use the associated doorbell page index in CREATE_QP and
  use the associated DB address while ringing the doorbell.

- BNXT_RE_METHOD_DBR_FREE:
  Free the allocated doorbell region.

- BNXT_RE_METHOD_GET_DEFAULT_DBR:
  Return the default doorbell page index and doorbell page address
  associated with the ucontext.

Link: https://patch.msgid.link/r/20260302110036.36387-4-sriharsha.basavapatna@broadcom.com
Co-developed-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/bnxt_re/ib_verbs.h

@@ -164,6 +164,13 @@ struct bnxt_re_user_mmap_entry {
 	u8 mmap_flag;
 };
 
+struct bnxt_re_dbr_obj {
+	struct bnxt_re_dev *rdev;
+	struct bnxt_qplib_dpi dpi;
+	struct bnxt_re_user_mmap_entry *entry;
+	atomic_t usecnt; /* QPs using this dbr */
+};
+
 struct bnxt_re_flow {
 	struct ib_flow		ib_flow;
 	struct bnxt_re_dev	*rdev;

drivers/infiniband/hw/bnxt_re/qplib_res.c

@@ -683,6 +683,49 @@ static int bnxt_qplib_alloc_pd_tbl(struct bnxt_qplib_res *res,
 }
 
 /* DPIs */
+int bnxt_qplib_alloc_uc_dpi(struct bnxt_qplib_res *res, struct bnxt_qplib_dpi *dpi)
+{
+	struct bnxt_qplib_dpi_tbl *dpit = &res->dpi_tbl;
+	struct bnxt_qplib_reg_desc *reg;
+	u32 bit_num;
+	int rc = 0;
+
+	reg = &dpit->wcreg;
+	mutex_lock(&res->dpi_tbl_lock);
+	bit_num = find_first_bit(dpit->tbl, dpit->max);
+	if (bit_num >= dpit->max) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+	/* Found unused DPI */
+	clear_bit(bit_num, dpit->tbl);
+	dpi->bit = bit_num;
+	dpi->dpi = bit_num + (reg->offset - dpit->ucreg.offset) / PAGE_SIZE;
+	dpi->umdbr = reg->bar_base + reg->offset + bit_num * PAGE_SIZE;
+unlock:
+	mutex_unlock(&res->dpi_tbl_lock);
+	return rc;
+}
+
+int bnxt_qplib_free_uc_dpi(struct bnxt_qplib_res *res, struct bnxt_qplib_dpi *dpi)
+{
+	struct bnxt_qplib_dpi_tbl *dpit = &res->dpi_tbl;
+	int rc = 0;
+
+	mutex_lock(&res->dpi_tbl_lock);
+	if (dpi->bit >= dpit->max) {
+		rc = -EINVAL;
+		goto unlock;
+	}
+
+	if (test_and_set_bit(dpi->bit, dpit->tbl))
+		rc = -EINVAL;
+	memset(dpi, 0, sizeof(*dpi));
+unlock:
+	mutex_unlock(&res->dpi_tbl_lock);
+	return rc;
+}
+
 int bnxt_qplib_alloc_dpi(struct bnxt_qplib_res *res,
 			 struct bnxt_qplib_dpi *dpi,
 			 void *app, u8 type)

drivers/infiniband/hw/bnxt_re/qplib_res.h

@@ -436,6 +436,10 @@ int bnxt_qplib_alloc_dpi(struct bnxt_qplib_res *res,
 			 void *app, u8 type);
 int bnxt_qplib_dealloc_dpi(struct bnxt_qplib_res *res,
 			   struct bnxt_qplib_dpi *dpi);
+int bnxt_qplib_alloc_uc_dpi(struct bnxt_qplib_res *res,
+			    struct bnxt_qplib_dpi *dpi);
+int bnxt_qplib_free_uc_dpi(struct bnxt_qplib_res *res,
+			   struct bnxt_qplib_dpi *dpi);
 void bnxt_qplib_cleanup_res(struct bnxt_qplib_res *res);
 int bnxt_qplib_init_res(struct bnxt_qplib_res *res);
 void bnxt_qplib_free_res(struct bnxt_qplib_res *res);

drivers/infiniband/hw/bnxt_re/uapi.c

@@ -331,9 +331,139 @@ DECLARE_UVERBS_NAMED_OBJECT(BNXT_RE_OBJECT_GET_TOGGLE_MEM,
 			    &UVERBS_METHOD(BNXT_RE_METHOD_GET_TOGGLE_MEM),
 			    &UVERBS_METHOD(BNXT_RE_METHOD_RELEASE_TOGGLE_MEM));
 
+static int UVERBS_HANDLER(BNXT_RE_METHOD_DBR_ALLOC)(struct uverbs_attr_bundle *attrs)
+{
+	struct bnxt_re_db_region dbr = {};
+	struct bnxt_re_ucontext *uctx;
+	struct bnxt_re_dbr_obj *obj;
+	struct ib_ucontext *ib_uctx;
+	struct bnxt_qplib_dpi *dpi;
+	struct bnxt_re_dev *rdev;
+	struct ib_uobject *uobj;
+	u64 mmap_offset;
+	int ret;
+
+	ib_uctx = ib_uverbs_get_ucontext(attrs);
+	if (IS_ERR(ib_uctx))
+		return PTR_ERR(ib_uctx);
+
+	uctx = container_of(ib_uctx, struct bnxt_re_ucontext, ib_uctx);
+	rdev = uctx->rdev;
+	uobj = uverbs_attr_get_uobject(attrs, BNXT_RE_ALLOC_DBR_HANDLE);
+
+	obj = kzalloc_obj(*obj);
+	if (!obj)
+		return -ENOMEM;
+
+	dpi = &obj->dpi;
+	ret = bnxt_qplib_alloc_uc_dpi(&rdev->qplib_res, dpi);
+	if (ret)
+		goto free_mem;
+
+	obj->entry = bnxt_re_mmap_entry_insert(uctx, dpi->umdbr,
+					       BNXT_RE_MMAP_UC_DB,
+					       &mmap_offset);
+	if (!obj->entry) {
+		ret = -ENOMEM;
+		goto free_dpi;
+	}
+
+	obj->rdev = rdev;
+	uobj->object = obj;
+	uverbs_finalize_uobj_create(attrs, BNXT_RE_ALLOC_DBR_HANDLE);
+
+	dbr.umdbr = dpi->umdbr;
+	dbr.dpi = dpi->dpi;
+	ret = uverbs_copy_to_struct_or_zero(attrs, BNXT_RE_ALLOC_DBR_ATTR,
+					    &dbr, sizeof(dbr));
+	if (ret)
+		return ret;
+
+	ret = uverbs_copy_to(attrs, BNXT_RE_ALLOC_DBR_OFFSET,
+			     &mmap_offset, sizeof(mmap_offset));
+	if (ret)
+		return ret;
+	return 0;
+free_dpi:
+	bnxt_qplib_free_uc_dpi(&rdev->qplib_res, dpi);
+free_mem:
+	kfree(obj);
+	return ret;
+}
+
+static int bnxt_re_dbr_cleanup(struct ib_uobject *uobject,
+			       enum rdma_remove_reason why,
+			       struct uverbs_attr_bundle *attrs)
+{
+	struct bnxt_re_dbr_obj *obj = uobject->object;
+	struct bnxt_re_dev *rdev = obj->rdev;
+
+	rdma_user_mmap_entry_remove(&obj->entry->rdma_entry);
+	bnxt_qplib_free_uc_dpi(&rdev->qplib_res, &obj->dpi);
+	return 0;
+}
+
+static int UVERBS_HANDLER(BNXT_RE_METHOD_GET_DEFAULT_DBR)(struct uverbs_attr_bundle *attrs)
+{
+	struct bnxt_re_db_region dpi = {};
+	struct bnxt_re_ucontext *uctx;
+	struct ib_ucontext *ib_uctx;
+	int ret;
+
+	ib_uctx = ib_uverbs_get_ucontext(attrs);
+	if (IS_ERR(ib_uctx))
+		return PTR_ERR(ib_uctx);
+
+	uctx = container_of(ib_uctx, struct bnxt_re_ucontext, ib_uctx);
+	dpi.umdbr = uctx->dpi.umdbr;
+	dpi.dpi = uctx->dpi.dpi;
+
+	ret = uverbs_copy_to_struct_or_zero(attrs, BNXT_RE_DEFAULT_DBR_ATTR,
+					    &dpi, sizeof(dpi));
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+DECLARE_UVERBS_NAMED_METHOD(BNXT_RE_METHOD_DBR_ALLOC,
+			    UVERBS_ATTR_IDR(BNXT_RE_ALLOC_DBR_HANDLE,
+					    BNXT_RE_OBJECT_DBR,
+					    UVERBS_ACCESS_NEW,
+					    UA_MANDATORY),
+			    UVERBS_ATTR_PTR_OUT(BNXT_RE_ALLOC_DBR_ATTR,
+						UVERBS_ATTR_STRUCT(struct bnxt_re_db_region,
+								   umdbr),
+								   UA_MANDATORY),
+			    UVERBS_ATTR_PTR_OUT(BNXT_RE_ALLOC_DBR_OFFSET,
+						UVERBS_ATTR_TYPE(u64),
+						UA_MANDATORY));
+
+DECLARE_UVERBS_NAMED_METHOD_DESTROY(BNXT_RE_METHOD_DBR_FREE,
+				    UVERBS_ATTR_IDR(BNXT_RE_FREE_DBR_HANDLE,
+						    BNXT_RE_OBJECT_DBR,
+						    UVERBS_ACCESS_DESTROY,
+						    UA_MANDATORY));
+
+DECLARE_UVERBS_NAMED_OBJECT(BNXT_RE_OBJECT_DBR,
+			    UVERBS_TYPE_ALLOC_IDR(bnxt_re_dbr_cleanup),
+			    &UVERBS_METHOD(BNXT_RE_METHOD_DBR_ALLOC),
+			    &UVERBS_METHOD(BNXT_RE_METHOD_DBR_FREE));
+
+DECLARE_UVERBS_NAMED_METHOD(BNXT_RE_METHOD_GET_DEFAULT_DBR,
+			    UVERBS_ATTR_PTR_OUT(BNXT_RE_DEFAULT_DBR_ATTR,
+						UVERBS_ATTR_STRUCT(struct bnxt_re_db_region,
+								   umdbr),
+						UA_MANDATORY));
+
+DECLARE_UVERBS_GLOBAL_METHODS(BNXT_RE_OBJECT_DEFAULT_DBR,
+			      &UVERBS_METHOD(BNXT_RE_METHOD_GET_DEFAULT_DBR));
+
 const struct uapi_definition bnxt_re_uapi_defs[] = {
 	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(BNXT_RE_OBJECT_ALLOC_PAGE),
 	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(BNXT_RE_OBJECT_NOTIFY_DRV),
 	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(BNXT_RE_OBJECT_GET_TOGGLE_MEM),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(BNXT_RE_OBJECT_DBR),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(BNXT_RE_OBJECT_DEFAULT_DBR),
 	{}
 };

include/uapi/rdma/bnxt_re-abi.h

@@ -163,6 +163,8 @@ enum bnxt_re_objects {
 	BNXT_RE_OBJECT_ALLOC_PAGE = (1U << UVERBS_ID_NS_SHIFT),
 	BNXT_RE_OBJECT_NOTIFY_DRV,
 	BNXT_RE_OBJECT_GET_TOGGLE_MEM,
+	BNXT_RE_OBJECT_DBR,
+	BNXT_RE_OBJECT_DEFAULT_DBR,
 };
 
 enum bnxt_re_alloc_page_type {
@@ -231,4 +233,31 @@ struct bnxt_re_packet_pacing_caps {
 struct bnxt_re_query_device_ex_resp {
 	struct bnxt_re_packet_pacing_caps packet_pacing_caps;
 };
+
+struct bnxt_re_db_region {
+	__u32 dpi;
+	__u32 reserved;
+	__aligned_u64 umdbr;
+};
+
+enum bnxt_re_obj_dbr_alloc_attrs {
+	BNXT_RE_ALLOC_DBR_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+	BNXT_RE_ALLOC_DBR_ATTR,
+	BNXT_RE_ALLOC_DBR_OFFSET,
+};
+
+enum bnxt_re_obj_dbr_free_attrs {
+	BNXT_RE_FREE_DBR_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+};
+
+enum bnxt_re_obj_default_dbr_attrs {
+	BNXT_RE_DEFAULT_DBR_ATTR = (1U << UVERBS_ID_NS_SHIFT),
+};
+
+enum bnxt_re_obj_dpi_methods {
+	BNXT_RE_METHOD_DBR_ALLOC = (1U << UVERBS_ID_NS_SHIFT),
+	BNXT_RE_METHOD_DBR_FREE,
+	BNXT_RE_METHOD_GET_DEFAULT_DBR,
+};
+
 #endif /* __BNXT_RE_UVERBS_ABI_H__*/