269b537c00
The whole coreboot generated `.config` has not been used since
ff0a27ad9c60 ("Use defconfig to generate .config"). The required
`coreboot.config` is much simpler now and can usually just be copied
from another model.
Signed-off-by: Tim Crawford <tcrawford@system76.com>
4.0 KiB
Adding a new board
In order to add support for a new board you will need the current proprietary BIOS ROM, the schematics for the system, and, if porting System76 EC, the EC specification document. While the BIOS ROM is available from the manufacturer, board schematics and EC specification typically require NDAs to access.
Recommended hardware
The presence of hardware will affect the output of the script used to generate the GPIO configuration for coreboot. It is recommended to have enough spare hardware to fill all available slots on the motherboard. This includes RAM modules, SATA drives, and M.2 modules. If the system has a Thunderbolt port, a dock will also be useful for verifying Thunderbolt and PCIe hotplug functionality.
These should be ready before attempting to boot a new port:
- An external programmer; for flashing the BIOS chip
- A Mega 2560; for flashing the EC and debug logging
Configuring the system
Before starting the porting process, the system should be configured to enable as many devices as possible to provide a more complete output for coreboot.
- If the motherboard has open slots (RAM, M.2, SATA), fill them
- Boot into the proprietary BIOS
- Enable things such as
- TPM
- Network stack
- VT-d
- Disable the Intel Management Engine (IME) if possible
- Exit, saving changes
- If the system is a laptop, connect to AC power with the adapter
- If the device has a Thunderbolt port, attach and authorize a TBT device
- If the device has a dGPU, ensure it present on the PCI bus
- On Pop!_OS, switch to NVIDIA graphics mode
sudo bash -c 'echo 1 > /sys/bus/pci/rescan'
Generating required output
The generate.sh script will perform most steps for collecting the required
data for coreboot and EC firmware development. If regenerating for an existing
model, it will automatically overwrite the data.
If planning to use System76 EC firmware, perform the following before running:
- Set keyboard backlight to full brightness and white light
- Set display backlight to full brightness
- Set CPU fan to full speed
./scripts/generate.sh <model> <firmware.rom> [ec.rom]
If the microcode blobs from coreboot will not be used, then microcode.rom
must be generated for the correct CPU set from the private intel-microcode
repo.
Other things that should be dumped before porting/flashing are:
- The kernel log (
dmesg) - DMI info (
dmidecode) - ACPI tables (
acpidump -b)
Porting coreboot
To port coreboot to a new board, see the coreboot documentation.
Add a coreboot.config file to the model directory. This can be copied from
another similar board as a reference, just updating the name. Typically, the
only special cases that need to be handled are when an FSP or microcode is
used that are not part of coreboot.
Smart amp
Boards may have a smart amp, which must be configured for speaker output to work.
The initialization data for Realtek smart amps can be dumped from the module
that does the codec init in proprietary firmware. The correct module can be
found using UEFITool by searching for the vendor/device ID of the codec, such
as "10ec1220" for the ALC1220. This is the start of the cim_verb_data array
in coreboot.
For info on the TI TAS5825M smart amp, see the smart-amp repo.
Configuring Intel CSME
The CSME image may need to be regenerated. Common changes that may be required are disabling Platform Trust Technology (PTT) so the discrete TPM device will work, and changing the Boot Guard profile to disable verified boot.
Porting System76 EC
To port System76 EC firmware to a new board, see the EC documentation.
Once System76 EC is ported, add ec.config.
echo "BOARD=system76/<model>" > models/<model>/ec.config"
If the proprietary EC was previously used, remove ec.rom and regenerate the
READMEs.