1 // SPDX-License-Identifier: GPL-2.0 2 // SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved. 3 4 //! MCTP/NVDM protocol types for NVIDIA GPU firmware communication. 5 //! 6 //! MCTP (Management Component Transport Protocol) carries NVDM (NVIDIA 7 //! Data Model) messages between the kernel driver and GPU firmware processors 8 //! such as FSP and GSP. 9 10 #![expect(dead_code)] 11 12 use kernel::pci::Vendor; 13 14 /// NVDM message type identifiers carried over MCTP. 15 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq)] 16 #[repr(u8)] 17 pub(crate) enum NvdmType { 18 #[default] 19 /// Chain of Trust boot message. 20 Cot = 0x14, 21 /// FSP command response. 22 FspResponse = 0x15, 23 } 24 25 impl TryFrom<u8> for NvdmType { 26 type Error = u8; 27 28 fn try_from(value: u8) -> Result<Self, Self::Error> { 29 match value { 30 x if x == u8::from(Self::Cot) => Ok(Self::Cot), 31 x if x == u8::from(Self::FspResponse) => Ok(Self::FspResponse), 32 _ => Err(value), 33 } 34 } 35 } 36 37 impl From<NvdmType> for u8 { 38 fn from(value: NvdmType) -> Self { 39 value as u8 40 } 41 } 42 43 bitfield! { 44 pub(crate) struct MctpHeader(u32), "MCTP transport header for NVIDIA firmware messages." { 45 31:31 som as bool, "Start-of-message bit."; 46 30:30 eom as bool, "End-of-message bit."; 47 29:28 seq as u8, "Packet sequence number."; 48 23:16 seid as u8, "Source endpoint ID."; 49 } 50 } 51 52 impl MctpHeader { 53 /// Builds a single-packet MCTP header (`SOM=1`, `EOM=1`, `SEQ=0`, `SEID=0`). 54 pub(crate) fn single_packet() -> Self { 55 Self::default().set_som(true).set_eom(true) 56 } 57 58 /// Returns whether this is a complete single-packet message (`SOM=1` and `EOM=1`). 59 pub(crate) fn is_single_packet(self) -> bool { 60 self.som() && self.eom() 61 } 62 } 63 64 /// MCTP message type for PCI vendor-defined messages. 65 const MSG_TYPE_VENDOR_PCI: u8 = 0x7e; 66 67 bitfield! { 68 pub(crate) struct NvdmHeader(u32), "NVIDIA Vendor-Defined Message header over MCTP." { 69 31:24 nvdm_type as u8 ?=> NvdmType, "NVDM message type."; 70 23:8 vendor_id as u16, "PCI vendor ID."; 71 6:0 msg_type as u8, "MCTP vendor-defined message type."; 72 } 73 } 74 75 impl NvdmHeader { 76 /// Builds an NVDM header for the given message type. 77 pub(crate) fn new(nvdm_type: NvdmType) -> Self { 78 Self::default() 79 .set_msg_type(MSG_TYPE_VENDOR_PCI) 80 .set_vendor_id(Vendor::NVIDIA.as_raw()) 81 .set_nvdm_type(nvdm_type) 82 } 83 84 /// Validates this header against the expected NVIDIA NVDM format and type. 85 pub(crate) fn validate(self, expected_type: NvdmType) -> bool { 86 self.msg_type() == MSG_TYPE_VENDOR_PCI 87 && self.vendor_id() == Vendor::NVIDIA.as_raw() 88 && matches!(self.nvdm_type(), Ok(nvdm_type) if nvdm_type == expected_type) 89 } 90 } 91