# Xeon Scalable Processor coreboot Community Preview Guide

## Background

Xeon 6 basic boot supports are initially upstreamed at https://review.coreboot.org/q/topic:”Xeon6-Basic-Boot”.

Full feature supports are previewed at https://review.coreboot.org/admin/repos/intel-dev-pub,general

The supported platform status are as below,

1. Beechnut City CRB (Sierra Forest-SP)

- Buildable and bootable with real FSP headers/binaries

2. Avenue City CRB (Granite Rapids-AP)

- Buildable and bootable with real FSP headers/binaries

## Targeted features list

1. ACPI

- RSDP/RSDT/XSDT/FADT/FACS/DSDT/SSDT

- MCFG/MADT/SRAT/SLIT/HMAT/DMAR/CEDT

- HEPT/SPMI/TPM2

- HEST/EINJ/ERST/BERT

2. SMBIOS

- Type 0 - BIOS information

- Type 1 - system information

- Type 2 - base board information

- Type 3 - chassis information

- Type 4 - processor information

- Type 17 - memory device

3. Hardware related

- Basic PCIe support

  - IIO bifurcation

  - PCIe hot plug

  - VT-d

- Customizable PCIe host bridge bus/MMIO resource window size for smart NIC support

  - To handle the case where a large amount of PFs/VFs will be presented under specific PCIe host bridge

- On-Chip accelerator (QAT, IAA, DSA, DLB)

- CXL 2.0 Type-3 memory

- NUMA and sub-NUMA clustering

- GPIO (with physical pins)

- Virtual GPIO

  - eSPI based, use BMC or CPLD to expand GPIO pin counts on PCH-less SoC

- BMC support

  - IPMI KCS

- Power Sequence

  - ACPI S0/S5

  - Fast cold/warm reset

- CPU OSPM

  - OS native (based on intel p_state/intel_idle OS driver)

- RAS

  - Based on FSP2.4 FSP-SMM

  - APEI support

  - Memory CE/UCE (firmware first mode, e.g. MCA/eMCA)

  - IIO CE/UCE (firmware first mode, e.g. DPC/eDPC)

4. Firmware related

- Boot to various payloads (Linux payload/TianoCore/UniversalPayload)

- Enlarged CBFS (>16MB) for one or multiple cloud payloads

- VPD

## Build steps

### Prepare workspace

    # Create workspace

    mkdir workspace && cd workspace

    # Prepare coreboot codebase

    git clone https://review.coreboot.org/intel-dev-pub
    ln -s intel-dev-pub/ coreboot

    # Switch to the branches you would like to use

    https://review.coreboot.org/admin/repos/intel-dev-pub,branches

    3.0_branch                    - Support of real platform boot
    3.0_feature_cxl               - Support of CXL Type-3 memory expander
    3.0_feature_fsp_smm_ras       - Support of RAS by FSP-SMM
    3.0_feature_gpio_vgpio        - Support of GPIO and virtual GPIO
    3.0_feature_iio_res_rebalance - Support of customized IIO resource (bus/MMIO) window for smart NICs
    3.0_feature_large_cbfs        - Support of 32MB/48MB CBFS for large cloud payloads
    3.0_feature_smbios            - Support of SMBIOS
    3.0_feature_snc               - Support of sub-NUMA clustering
    3.0_feature_var_car_code_sz   - Support of user defined cache-as-RAM code size

    # Prepare stub binaries and update their path in
    # configs/builder/config.intel.crb.avc

    # Granite Rapids coreboot uses FSP 2.4, where FSP-I is newly introduced
    # as an optional module to provide FSP based SMM capability. For FSP 2.4
    # and FSP-I, please further refer to:
    # https://cdrdv2-public.intel.com/736809/736809_FSP_EAS_v2.4_Errata_A.pdf

    CONFIG_IFD_BIN_PATH=<path of intel flash descriptor blob>
    CONFIG_PBP_BIN_PATH=<path of platform boot policy blob>
    CONFIG_CPU_UCODE_BINARIES=<path of ucode>
    CONFIG_FSP_T_FILE=<path of FSP-T binary>
    CONFIG_FSP_M_FILE=<path of FSP-M binary>
    CONFIG_FSP_S_FILE=<path of FSP-S binary>
    CONFIG_FSP_I_FILE=<path of FSP-I binary, optional, to comment out if not using>
    CONFIG_PAYLOAD_FILE=<path of payload binary>

### Download necessary submodules

    git submodule update --init --checkout 3rdparty/vboot

### Or take below alternative if the network connection is not good

    git clone https://github.com/coreboot/vboot.git 3rdparty/vboot/

### Build toolchain

    make crossgcc-i386 CPUS=$(nproc)

### Build BIOS (Avenue City CRB)

    make distclean

    make defconfig KBUILD_DEFCONFIG=configs/builder/config.intel.crb.avc

    make UPDATED_SUBMODULES=1 -j`nproc`

### Build BIOS (Beechnut City CRB)

    make distclean

    make defconfig KBUILD_DEFCONFIG=configs/builder/config.intel.crb.bnc

    make UPDATED_SUBMODULES=1 -j`nproc`

### Obtain the preview patch list

    # The tag ‘upstream’ points to the upstream commit that the preview
    # branch is based on.

    git format-patch upstream..HEAD

## About Granite Rapids FSP binaries and other needed firmware ingredients

For the real Granite Rapids FSP binaries, please contact intel business interface to obtain them. Then please update below config files to apply.

    configs/builder/config.intel.crb.avc
    configs/builder/config.intel.crb.bnc

The following firmware ingredients are also obtained and applied using the same process:

- Microcode updates

- Intel Flash Descriptor

- Platform Boot Policy

## Test Environment

- LinuxBoot - linux kernel tag v6.10-rc4 (with defconfig located in: `Documentation/soc/intel/xeon_sp/linuxboot_defconfig`)

- OS - CentOS Stream 9 Linux version 5.14.0-479.el9.x86_64 (mockbuild@x86-05.stream.rdu2.redhat.com)