Creating A devicetree.cb: Difference between revisions

Latest revision as of 13:51, 2 March 2014

This article should help people who are writting a devicetree.cb for their system.

What you will need

While running GNU/Linux on the vendor BIOS, collect the output from:

dmesg
lspci -ntvvv
cat /proc/ioports

If you have support for your board in serialice you may wish to gather its output also.

Reading lspci output

The Peripheral Component Interconnect (PCI) is a standerdized local bus for attaching different hardwares to motherboard.

The lspci command reads the bus information and topology, its output format is given by example:

03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader (rev 01)
+------ +----------------------  +--------------------------------------------------------------
^       ^                        ^
|       |                        |
|       |                        Field 3: Name of device attached and its manufactured company name. 
|       Field 2: PCI slot name.
Field 1: PCI bus slot number.

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 & Symbols

<source lang="ada"> chip, device, register,on,off,pci,ioapic,pnp,i2c,lapic,cpu_cluster,domain,irq,drq,io,ioapic_irq,inherit,subsystemid,end,= </source>

Syntax

ioapic_irq

<source lang="ada"> ioapic_irq: ioapic_irq number-literal pciint number-literal </source>

rewrite this in BNF notation..

Grammar

Literals

Literal values types are defined and thus consumed by the following regular expressions:

Hex

<source lang="reg"> 0x[0-9a-fA-F.]+

[0-9a-fA-F.]+ </source>

Decimals

PCI Interrupts

Strings

<source lang="reg"> \"[^\"]+\"

[^ \n\t]+ </source>

NOTES

See source util/sconfig/sconfig.* for devicetree compiler..

Examples

NorthBridge

..

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

This file is licensed under Creative Commons Attribution 2.5 License.
In short: you are free to distribute and modify the file as long as you attribute its author(s) or licensor(s).

@@ Line 1: / Line 1: @@
-This article should help people who are writting a devicetree.cb for their system.
+This article should help people who are writting a '''devicetree.cb''' for their system.
 == What you will need ==
- * ''lspci -nvvv'' output
+While running GNU/Linux on the vendor BIOS, collect the output from:
+* '''dmesg'''
+* '''lspci -ntvvv'''
+* '''cat /proc/ioports'''
+If you have support for your board in '''serialice''' you may wish to gather its output also.
+== Reading '''lspci''' output ==
+The Peripheral Component Interconnect ('''PCI''') is a standerdized local bus for attaching different hardwares to motherboard.
+The '''lspci''' command reads the bus information and topology, its output format is given by example:
+:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader (rev 01)
+ +------ +----------------------  +--------------------------------------------------------------
+ ^       ^                        ^
+ |       |                        |
+ |       |                        Field 3: Name of device attached and its manufactured company name.
+ |       Field 2: PCI slot name.
+ Field 1: PCI bus slot number.
 == Introduction ==
@@ Line 12: / Line 32: @@
 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 & Symbols ==
+<source lang="ada">
+chip, device, register,on,off,pci,ioapic,pnp,i2c,lapic,cpu_cluster,domain,irq,drq,io,ioapic_irq,inherit,subsystemid,end,=
+</source>
+== Syntax ==
+* ioapic_irq
+<source lang="ada">
+ioapic_irq: ioapic_irq number-literal pciint number-literal
+</source>
+rewrite this in BNF notation..
+== Grammar ==
+=== Literals ===
+Literal values types are defined and thus consumed by the following regular expressions:
+* Hex
+<source lang="reg">
+x[0-9a-fA-F.]+
+[0-9a-fA-F.]+
+</source>
+* Decimals
+<source lang="reg">
+[0-9.]+
+</source>
+* PCI Interrupts
+<source lang="reg">
+INT[A-D]
+</source>
+* Strings
+<source lang="reg">
+\"[^\"]+\"
+[^ \n\t]+
+</source>
+== NOTES ==
+See source  util/sconfig/sconfig.* for devicetree compiler..
+== Examples ==
+=== NorthBridge ===
+..
+=== 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
+{{Cc-by-2.5}}