drivers/infiniband/hw/hfi1/opfn.h

   1 /* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
   2 /*
   3  * Copyright(c) 2018 Intel Corporation.
   4  *
   5  */
   6 #ifndef _HFI1_OPFN_H
   7 #define _HFI1_OPFN_H
   8
   9 /**
  10  * DOC: Omni Path Feature Negotion (OPFN)
  11  *
  12  * OPFN is a discovery protocol for Intel Omni-Path fabric that
  13  * allows two RC QPs to negotiate a common feature that both QPs
  14  * can support. Currently, the only OPA feature that OPFN
  15  * supports is TID RDMA.
  16  *
  17  * Architecture
  18  *
  19  * OPFN involves the communication between two QPs on the HFI
  20  * level on an Omni-Path fabric, and ULPs have no knowledge of
  21  * OPFN at all.
  22  *
  23  * Implementation
  24  *
  25  * OPFN extends the existing IB RC protocol with the following
  26  * changes:
  27  * -- Uses Bit 24 (reserved) of DWORD 1 of Base Transport
  28  *    Header (BTH1) to indicate that the RC QP supports OPFN;
  29  * -- Uses a combination of RC COMPARE_SWAP opcode (0x13) and
  30  *    the address U64_MAX (0xFFFFFFFFFFFFFFFF) as an OPFN
  31  *    request; The 64-bit data carried with the request/response
  32  *    contains the parameters for negotiation and will be
  33  *    defined in tid_rdma.c file;
  34  * -- Defines IB_WR_RESERVED3 as IB_WR_OPFN.
  35  *
  36  * The OPFN communication will be triggered when an RC QP
  37  * receives a request with Bit 24 of BTH1 set. The responder QP
  38  * will then post send an OPFN request with its local
  39  * parameters, which will be sent to the requester QP once all
  40  * existing requests on the responder QP side have been sent.
  41  * Once the requester QP receives the OPFN request, it will
  42  * keep a copy of the responder QP's parameters, and return a
  43  * response packet with its own local parameters. The responder
  44  * QP receives the response packet and keeps a copy of the requester
  45  * QP's parameters. After this exchange, each side has the parameters
  46  * for both sides and therefore can select the right parameters
  47  * for future transactions
  48  */
  49
  50 #include <linux/workqueue.h>
  51 #include <rdma/ib_verbs.h>
  52 #include <rdma/rdmavt_qp.h>
  53
  54 /* STL Verbs Extended */
  55 #define IB_BTHE_E_SHIFT           24
  56 #define HFI1_VERBS_E_ATOMIC_VADDR U64_MAX
  57
  58 enum hfi1_opfn_codes {
  59         STL_VERBS_EXTD_NONE = 0,
  60         STL_VERBS_EXTD_TID_RDMA,
  61         STL_VERBS_EXTD_MAX
  62 };
  63
  64 struct hfi1_opfn_data {
  65         u8 extended;
  66         u16 requested;
  67         u16 completed;
  68         enum hfi1_opfn_codes curr;
  69         /* serialize opfn function calls */
  70         spinlock_t lock;
  71         struct work_struct opfn_work;
  72 };
  73
  74 /* WR opcode for OPFN */
  75 #define IB_WR_OPFN IB_WR_RESERVED3
  76
  77 void opfn_send_conn_request(struct work_struct *work);
  78 void opfn_conn_response(struct rvt_qp *qp, struct rvt_ack_entry *e,
  79                         struct ib_atomic_eth *ateth);
  80 void opfn_conn_reply(struct rvt_qp *qp, u64 data);
  81 void opfn_conn_error(struct rvt_qp *qp);
  82 void opfn_qp_init(struct rvt_qp *qp, struct ib_qp_attr *attr, int attr_mask);
  83 void opfn_trigger_conn_request(struct rvt_qp *qp, u32 bth1);
  84 int opfn_init(void);
  85 void opfn_exit(void);
  86
  87 #endif /* _HFI1_OPFN_H */