54 lines
1.9 KiB
C
54 lines
1.9 KiB
C
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/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
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/*
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* Copyright(c) 2018 Intel Corporation.
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*
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*/
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#ifndef _HFI1_OPFN_H
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#define _HFI1_OPFN_H
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/**
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* DOC: Omni Path Feature Negotion (OPFN)
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*
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* OPFN is a discovery protocol for Intel Omni-Path fabric that
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* allows two RC QPs to negotiate a common feature that both QPs
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* can support. Currently, the only OPA feature that OPFN
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* supports is TID RDMA.
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*
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* Architecture
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*
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* OPFN involves the communication between two QPs on the HFI
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* level on an Omni-Path fabric, and ULPs have no knowledge of
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* OPFN at all.
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*
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* Implementation
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*
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* OPFN extends the existing IB RC protocol with the following
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* changes:
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* -- Uses Bit 24 (reserved) of DWORD 1 of Base Transport
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* Header (BTH1) to indicate that the RC QP supports OPFN;
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* -- Uses a combination of RC COMPARE_SWAP opcode (0x13) and
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* the address U64_MAX (0xFFFFFFFFFFFFFFFF) as an OPFN
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* request; The 64-bit data carried with the request/response
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* contains the parameters for negotiation and will be
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* defined in tid_rdma.c file;
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* -- Defines IB_WR_RESERVED3 as IB_WR_OPFN.
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*
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* The OPFN communication will be triggered when an RC QP
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* receives a request with Bit 24 of BTH1 set. The responder QP
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* will then post send an OPFN request with its local
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* parameters, which will be sent to the requester QP once all
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* existing requests on the responder QP side have been sent.
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* Once the requester QP receives the OPFN request, it will
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* keep a copy of the responder QP's parameters, and return a
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* response packet with its own local parameters. The responder
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* QP receives the response packet and keeps a copy of the requester
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* QP's parameters. After this exchange, each side has the parameters
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* for both sides and therefore can select the right parameters
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* for future transactions
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*/
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/* STL Verbs Extended */
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#define IB_BTHE_E_SHIFT 24
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#endif /* _HFI1_OPFN_H */
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