Solved Cross kernel build fails FDT on 13.1

[aribi]

Looks like cross-compiled kernel (amd64->arm) fails to pick up options FDT from the kernel config file.

Starting with a clean /usr/src the built kernel does not contain code for FDT support. Steps taken:

# uname -a
FreeBSD bobthebuilder.localdomain 13.1-RELEASE FreeBSD 13.1-RELEASE releng/13.1-n250148-fc952ac2212 GENERIC  amd64
# rm -R /usr/src
# tar -C / -xvf src.txz
# cd /usr/src
# make TARGET=arm KERNCONF=GENERIC -j 24 buildkernel
# grep FDT /usr/obj/usr/src/arm.armv7/sys/GENERIC/opt_global.h
#

So the kernel build process ignored the options FDT setting in src/sys/arm/conf/GENERIC and did not write a #define for it in opt_global.h.
As a result any driver code that is ifdefed FDT will not make it's way into the binary.

What am I doing wrong here?

 

[Phishfry]

What am I doing wrong here?

You never told the compiler you need FDT. Plus your env is not set.
-DWITH_FDT

Here is an old arm6 build. Use it as an example. arm6 is dead so you will need to adjust.

Cross-compiling Beaglebone on amd64

Well I got tired of using crochet as a crutch and I figured out how to cross compile for Beaglebone. At first I cheated and wrote to the microSD Card, but I buckled down and figured out how to manipulate a memory disk. [Copy Source to Build Dir] mkdir /BBB cp -vipr /usr/src /BBB/src mkdir...

forums.freebsd.org

 

[Phishfry]

Which Arm platform are you building for? arm, armv7 or aarch64/arm64 ? What board?
Is there a FreeBSD port with u-boot for the board?

 

[aribi]

Tried it, sadly doesn't fix.

And your instruction adds -DWITH_FDT for buildworld, not for buildkernel:

.....
[Move to base dir and build world and kernel]
cd $BASEDIR/src
make -j8 buildworld TARGET=arm TARGET_ARCH=armv6 UBLDR_LOADADDR=0x88000000 -DWITH_FDT __MAKE_CONF=/dev/null SRCCONF=/dev/null
make buildkernel TARGET_ARCH=armv6 KERNCONF=BEAGLEBONE
.....

 

[aribi]

Which Arm platform are you building for? arm, armv7 or aarch64/arm64 ? What board?
Is there a FreeBSD port with u-boot for the board?

Working on pcduino3-nano - which is A20.

U-boot works OK. Using u-boot-pcduino3 with simple patch on Makefile:

*** Makefile    2022-06-08 22:10:59.859770000 +0200
--- Makefile.org    2022-06-08 22:08:00.035792000 +0200
***************
*** 1,10 ****
  # $FreeBSD: head/sysutils/u-boot-pcduino3/Makefile 472714 2018-06-18 20:22:13Z linimon $
 
- .include "${MASTERDIR}/Makefile"
  MASTERDIR=    ${.CURDIR}/../u-boot-master
 
! MODEL=        pcduino3-nano
! BOARD_CONFIG=    Linksprite_pcDuino3_Nano_defconfig
  FAMILY=        allwinner
 
  .include "${MASTERDIR}/Makefile"
--- 1,9 ----
  # $FreeBSD: head/sysutils/u-boot-pcduino3/Makefile 472714 2018-06-18 20:22:13Z linimon $
 
  MASTERDIR=    ${.CURDIR}/../u-boot-master
 
! MODEL=        pcduino3
! BOARD_CONFIG=    Linksprite_pcDuino3_defconfig
  FAMILY=        allwinner
 
  .include "${MASTERDIR}/Makefile"

But generic kernel needs some fixes for some devices (dwc with rgmii-id - camcontrol ahci).
Mods on the kernel were done on system upgraded to 13.1.
Everything went fine - board boots ok - dwc started working recognizing phy.

Until ... On the cross-compiling host I started to implement my mods on a fresh install of src.txz in /usr/src.
After that the FDT option seems to be ignored. I notice from /usr/obj/usr/src/arm.armv7/sys/GENERIC/opt_global.h all the options from /usr/src/sys/arm/conf/std.armv7 are imported.
But - at least - options FDT from GENERIC is missing.

 

[aribi]

Found the culprit. Seems some older code uses #ifdef FDT which is mitigated by juggling with OPT_FDT.
/usr/src/sys/conf/kern.opts.mk comments on using

.if !empty(OPT_FDT)

In various Makefiles in the /usr/src/sys/modules tree this is done.

But not in /usr/src/sys/dev part or the tree.

Gleaning from /usr/src/sys/dev/mii/vscphy.c the chosen solution for this part of the source tree is to

#include "opt_platform.h"

After adding this the #ifdef FDT wrapped code from /usr/src/sys/dev is compiled in correctly.