Creating A devicetree.cb
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This article should help people who are writting a devicetree.cb for their system.
What you will need
- lspci -nvvv output
Introduction
The mainboard's devicetree.cb file contains many build and platform configuration settings. One of the most important items is the mainboard device list.
A device needs to be listed in the mainboard devicetree.cb if it requires more setup than standard PCI initialization (resource allocation). Typically, that includes the CPU, northbridge, southbridge, and Super I/O. These devices are usually required for system specific configuration as well as indicate the system bus structure (pci_domain).
When a device in devicetree.cb is found during the coreboot PCI/system scan process the functions to do customized initialization are called via the device_operations and the chip_operations structures. You will find these structures in the devices source files.
Keywords
.. <source lang="ada"> pci, chip, device, register, on, off, end, io, irq, drq </source>
Syntax
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Grammar
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Examples
NorthBridge
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Super I/O
» chip superio/fintek/f71869ad » » device pnp 4e.00 off # Floppy » » » io 0x60 = 0x3f0 » » » irq 0x70 = 6 » » » drq 0x74 = 2 » » end » » device pnp 4e.01 on # COM1 » » » io 0x60 = 0x3f8 » » » irq 0x70 = 4 » » end » » » device pnp 4e.02 off # COM2 » » » io 0x60 = 0x2f8 » » » irq 0x70 = 3 » » end » » device pnp 4e.03 off # Parallel Port » » » io 0x60 = 0x378 » » » irq 0x70 = 7 » » » drq 0x74 = 3 » » end » » device pnp 4e.04 on # Hardware Monitor » » » io 0x60 = 0x295 » » » irq 0x70 = 0 » » end » » device pnp 4e.05 on # KBC » » » io 0x60 = 0x060 » » » irq 0x70 = 1 # Keyboard IRQ » » » irq 0x72 = 12 # Mouse IRQ » » end » » device pnp 4e.06 off end # GPIO » » device pnp 4e.07 on end # BSEL » » device pnp 4e.0a off end # PME » end # f71869ad
 
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