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