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>
115 lines
4.0 KiB
Markdown
115 lines
4.0 KiB
Markdown
# Adding a new board
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In order to add support for a new board you will need the current proprietary
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BIOS ROM, the schematics for the system, and, if porting System76 EC, the EC
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specification document. While the BIOS ROM is available from the manufacturer,
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board schematics and EC specification typically require NDAs to access.
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## Recommended hardware
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The presence of hardware will affect the output of the script used to generate
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the GPIO configuration for coreboot. It is recommended to have enough spare
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hardware to fill all available slots on the motherboard. This includes RAM
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modules, SATA drives, and M.2 modules. If the system has a Thunderbolt port, a
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dock will also be useful for verifying Thunderbolt and PCIe hotplug
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functionality.
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These should be ready before attempting to boot a new port:
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- An [external programmer][external-programmer]; for flashing the BIOS chip
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- A [Mega 2560][mega2560]; for flashing the EC and debug logging
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## Configuring the system
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Before starting the porting process, the system should be configured to
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enable as many devices as possible to provide a more complete output for
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coreboot.
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1. If the motherboard has open slots (RAM, M.2, SATA), fill them
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2. Boot into the proprietary BIOS
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3. Enable things such as
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- TPM
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- Network stack
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- VT-d
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4. Disable the Intel Management Engine (IME) if possible
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5. Exit, saving changes
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6. If the system is a laptop, connect to AC power with the adapter
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7. If the device has a Thunderbolt port, attach and authorize a TBT device
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8. If the device has a dGPU, ensure it present on the PCI bus
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- On Pop!\_OS, switch to NVIDIA graphics mode
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```
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sudo bash -c 'echo 1 > /sys/bus/pci/rescan'
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```
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## Generating required output
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The `generate.sh` script will perform most steps for collecting the required
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data for coreboot and EC firmware development. If regenerating for an existing
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model, it will automatically overwrite the data.
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If planning to use System76 EC firmware, perform the following before running:
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- Set keyboard backlight to full brightness and white light
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- Set display backlight to full brightness
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- Set CPU fan to full speed
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```
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./scripts/generate.sh <model> <firmware.rom> [ec.rom]
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```
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If the microcode blobs from coreboot will not be used, then `microcode.rom`
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must be generated for the correct CPU set from the private [intel-microcode]
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repo.
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Other things that should be dumped before porting/flashing are:
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- The kernel log (`dmesg`)
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- DMI info (`dmidecode`)
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- ACPI tables (`acpidump -b`)
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## Porting coreboot
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To port coreboot to a new board, see the coreboot documentation.
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Add a `coreboot.config` file to the model directory. This can be copied from
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another similar board as a reference, just updating the name. Typically, the
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only special cases that need to be handled are when an FSP or microcode is
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used that are not part of coreboot.
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### Smart amp
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Boards may have a smart amp, which must be configured for speaker output to
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work.
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The initialization data for Realtek smart amps can be dumped from the module
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that does the codec init in proprietary firmware. The correct module can be
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found using UEFITool by searching for the vendor/device ID of the codec, such
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as "10ec1220" for the ALC1220. This is the start of the `cim_verb_data` array
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in coreboot.
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For info on the TI TAS5825M smart amp, see the [smart-amp] repo.
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## Configuring Intel CSME
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The CSME image may need to be regenerated. Common changes that may be required
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are disabling Platform Trust Technology (PTT) so the discrete TPM device will
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work, and changing the Boot Guard profile to disable verified boot.
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## Porting System76 EC
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To port System76 EC firmware to a new board, see the EC documentation.
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Once System76 EC is ported, add `ec.config`.
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```
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echo "BOARD=system76/<model>" > models/<model>/ec.config"
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```
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If the proprietary EC was previously used, remove `ec.rom` and regenerate the
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READMEs.
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[external-programmer]: ./flashing.md#external-programmer
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[intel-microcode]: https://github.com/system76/intel-microcode
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[mega2560]: https://github.com/system76/ec/blob/master/doc/mega2560.md
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[smart-amp]: https://github.com/system76/smart-amp
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