Motherboard Porting Guide

Motherboard Porting Guide

Please note that this is WIP work.

HOWTO to find a way

• find a model and manufacturer of your mobo
• download these tools:

 # git clone http://review.coreboot.org/p/coreboot
 # superiotool (  cd coreboot/util/superiotool ; make ; sudo make install )
 # inteltool ( cd coreboot/util/inteltool ; make ; sudo make install )
 # ectool ( cd coreboot/util/ectool ; make ; sudo make install )
 # dmidecode ( cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:/sources/dmidecode co dmidecode )
 # msrtool ( cd coreboot/util/msrtool ; ./configure ; make ; sudo make install )
 # nvramtool ( cd coreboot/util/nvramtool ; make ; sudo make install )
 # flashrom ( svn co svn://coreboot.org/flashrom/trunk flashrom )

• make and install them (make; sudo make install) - you need at least libpci/pciutils
• check that your distro have this tools and install them:

 # lspci
 # dmesg
 # acpitool
 # lspnp
 # lsusb
 # acpidump

• Do this commands:

 # lspci -nnvvvxxxx > lspci.log
 # lspnp -vv > lspnp.log
 # lsusb -vvv > lsusb.log
 # superiotool -deV > superiotool.log
 # inteltool -a > inteltool.log
 # ectool > ectool.log
 # msrtool > msrtool.log
 # dmidecode > dmidecode.log
 # biosdecode > biosdecode.log
 # nvramtool -x > nvramtool.log
 # dmesg > dmesg.log
 # flashrom -V -p internal:laptop=force_I_want_a_brick > flashrom_info.log
 # flashrom -V -p internal:laptop=force_I_want_a_brick -r rom.bin > flashrom_read.log
 # acpidump > acpidump.log
 # for x in /sys/class/sound/card0/hw*; do cat "$x/init_pin_configs" > pin_"$(basename "$x")"; done
 # for x in /proc/asound/card0/codec#*; do cat "$x" > "$(basename "$x")"; done

• Save all logs in safe place, and also rom.bin file.
• Find what chip does your mobo use. The name of the chip is present in flashrom_info.log but is not always exact as some chips have several packaging variants (e.g. SOIC-16, SOIC-8 and TSOP). Consult [[1]] for more info on possible chip formats. If possible make a high-resolution (600dpi or higher) scan of motherboard. Make a scan, not a photo as cameras typically don't have enough resolution to identify individual chips.
• try to find information - what EC (if on laptop) or Super I/O chip (if any) is used in your mobo (may be some info in Service Manuals or Disassembly guides)
• try to find your Super I/O / EC chip datasheet

For laptop, additionally:

• if you see that ectool return some fake staff - like only 'FF' or '00' - so you have custom EC configuration, it's a hard work for support
• if you see that ectool return looks like 'right' output - you have a big chances for support
• you need to find from thease outputs Super I/O / EC chip name, or if not see this - disassembly your laptop

Preparing recovery method

Inevitably when you develop coreboot there will be unbootable builds and so you need a way to unbrick your machine after a failed image. There are several ways to do so. Main ones are:

• In-system Programming. For more info consult [[2]]
• Hotswap. Consult [[3]]

In any case you have to locate the flash chip. Note the chipname from flashrom output. Teardown your system and find that chip. For how it usually looks like consult [[4]]. If you have a scanner, do a high-resolution scan of your board, it may be useful later.

Selecting Similar Board

Most important criteria for finding similar board is chipset. Look at northbridge (device 0:0.0) and southbridge (LPC controller) in the lspci output. grep through coreboot tree to find how those chipsets are named, then grep for chipset name (case-insensitive) to find a board which uses it. If there are several of them, try to match (in order of decreasing importance) system type (desktop/laptop), SuperI/O and manufacturer.

Adding a new board

This is a two step process. If you mainboard already exists, skip to next section.

Adding a new vendor to tree

Create a directory in src/mainboard with the same name as vendor name. Add to src/mainboard/Kconfig new vendor entry, the rest of this example uses "foo" vendor.

config VENDOR_FOO
      bool "Foo"

Add also a include for new Kconfig file which holds the vendor motherboards in the vendor directory

source "src/mainboard/foo/Kconfig"

Create a src/mainboard/foo/Kconfig, copy from other vendor, and change the vendor name. Delete all mainboards.

Adding a new motherboard to tree

Asume that vendor name is foo and board type is bar. Add new configuration item in src/mainboard/foo/Kconfig

config BOARD_FOO_BAR
       bool "BAR"

Add include for board specific config:

source "src/mainboard/foo/bar/Kconfig"

Adjusting contents of new board directory

Now copy your similar board and start adjusting. Your first stop is the Kconfig.

• You need to change the condition in the first line to match your board:

-if BOARD_VENDOR_BAR +if BOARD_VENDOR_BAZ

• Change MAINBOARD_DIR and names
• Change device options to match your config
• Next stop go to mainboard.c and adjust GPIO config based on inteltool dump above.

Look through the options and adjust

Adjust Kconfig to fit the new vendor/model name and dont forget to change MAINBOARD_DIR and MAINBOARD_PART_NUMBER.