[Buildroot] Adding USB support to existing device on 2.6.39.3 kernel - possible?

Thu Mar 31 05:57:59 UTC 2022

On 2022-03-30 19:18, Dan Jackson wrote:
>> -----Original Message-----
>> From: Andreas Ziegler <br015 at umbiko.net>
>> Sent: 30 March 2022 08:14
>> To: Dan Jackson <dan at thejacksons.uk>
>> Cc: buildroot at buildroot.org
>> Subject: Re: Adding USB support to existing device on 2.6.39.3 kernel 
>> -
>> possible?
>> 
>> Hi Dan,
>> 
>> cutting some old content.
>> 
>> On 2022-03-29 19:19, Dan Jackson wrote:
>> 
>> <cut>
>> 
>> >> > However, now I have a new missing file error, and I can't seem to
>> >> > locate a suitable candidate:
>> >> >
>> >> > In file included from
>> >> > /home/danj/buildroot-2022.02/output/build/linux-
>> >> custom/arch/arm/include/asm/system.h:165,
>> >> >                  from
>> >> > /home/danj/buildroot-2022.02/output/build/linux-
>> >> custom/arch/arm/include/asm/bitops.h:27,
>> >> >                  from include/linux/bitops.h:22,
>> >> >                  from include/linux/kernel.h:17,
>> >> >                  from include/linux/sched.h:55,
>> >> >                  from arch/arm/kernel/asm-offsets.c:13:
>> >> > /home/danj/buildroot-2022.02/output/build/linux-
>> >> custom/arch/arm/include/asm/memory.h:19:10:
>> >> > fatal error: mach/memory.h: No such file or directory
>> >> >    19 | #include <mach/memory.h>
>> >> >       |          ^~~~~~~~~~~~~~~
>> >> > compilation terminated.
>> >> > /home/danj/buildroot-2022.02/output/build/linux-custom/./Kbuild:81:
>> >> > recipe for target 'arch/arm/kernel/asm-offsets.s' failed
>> >> > make[3]: *** [arch/arm/kernel/asm-offsets.s] Error 1
>> >> > Makefile:1009: recipe for target 'prepare0' failed
>> >> > make[2]: *** [prepare0] Error 2
>> >> > make[2]: *** Waiting for unfinished jobs....
>> >> >   HOSTCC  scripts/mod/modpost.o
>> >> >   HOSTCC  scripts/mod/sumversion.o
>> >> >   HOSTLD  scripts/mod/modpost
>> >> > make[2]: *** wait: No child processes. Stop.
>> >> > package/pkg-generic.mk:289: recipe for target
>> >> > '/home/danj/buildroot-2022.02/output/build/linux-
>> custom/.stamp_built'
>> >> > failed
>> >> > make[1]: ***
>> >> > [/home/danj/buildroot-2022.02/output/build/linux-custom/.stamp_buil
>> >> > t]
>> >> > Error 2
>> >> > Makefile:84: recipe for target '_all' failed
>> >> > make: *** [_all] Error 2
>> >>
>> >> This seems not to be the defconfig from above? It now uses
>> >> linux-custom ...
>> >> The failure may be due to the default kernel configuration. Try to
>> >> configure the correct one and see if you get further.
>> >>
>> >> > I think maybe I am still doing something wrong because it sure
>> >> > seems to be compiling a lot of stuff instead of letting me configure
>> things.
>> >>
>> >> It gets better once everything necessary is built.
>> >
>> > Still no luck I'm afraid. Same error with mach/memory.h as above.
>> >
>> > Buildroot defconfig now looks like this:
>> >
>> > BR2_armeb=y
>> > BR2_STATIC_LIBS=y
>> > BR2_KERNEL_HEADERS_VERSION=y
>> > BR2_DEFAULT_KERNEL_VERSION="2.6.39.3"
>> > BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_REALLY_OLD=y
>> > BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
>> > BR2_PTHREAD_DEBUG=y
>> > BR2_BINUTILS_VERSION_2_37_X=y
>> > BR2_GCC_VERSION_9_X=y
>> > BR2_TOOLCHAIN_BUILDROOT_CXX=y
>> > BR2_PACKAGE_HOST_GDB=y
>> > BR2_GDB_VERSION_9_2=y
>> > BR2_LINUX_KERNEL=y
>> > BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>> > BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="2.6.39.3"
>> > BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>> >
>> BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="/home/danj/DG3270_9.1.103
>> FB/sourcecode/ti_linux/linux-2.6.39.3/src/.config"
>> > BR2_PACKAGE_DROPBEAR=y
>> >
>> BR2_PACKAGE_DROPBEAR_LOCALOPTIONS_FILE="/home/danj/localoptions
>> .h"
>> > BR2_PACKAGE_JOE=y
>> >
>> > I forgot to mention this before but the buildroot manual page you
>> > mentioned said to create a local.mk file in order to use external
>> > source, this looks like this:
>> >
>> > LINUX_OVERRIDE_SRCDIR =
>> > /home/danj/DG3270_9.1.103FB/sourcecode/ti_linux/linux-2.6.39.3/src/
>> >
>> > For the kernel configuration I entered the kernel source dir and did
>> > "make menuconfig", I left everything at the defaults except for
>> > enabling the USB related items.
>> >
>> > The resulting configuration file is attached as a text file.
>> > Unfortunately it's been literally decades since I last actually
>> > compiled a kernel, so I'm afraid I have no idea what bits would be
>> > suitable to disable/remove to get the results I want (I'm guessing
>> > this will be the most likely way to eliminate the error I'm getting?)
>> 
>> I did a compile test this morning, the Buildroot version was some 
>> early
>> 2022.02 version, not up-to-date.
>> 
>> You have a potential header mismatch, Select Toolchain -> Kernel 
>> Headers
>> -> Same as kernel being built to use the vendor source also for the
>> headers.
>> 
>> I could configure Linux with make menuconfig, did not encounter the
>> missing memory.h error above, but the build stops during Linux kernel
>> compilation with this error:
>> 
>> /tmp/ccSO8f6S.s: Assembler messages:
>> /tmp/ccSO8f6S.s:950: Error: .err encountered
>> make[3]: *** [scripts/Makefile.build:284:
>> arch/arm/kernel/sys_oabi-compat.o] Error 1
>> make[2]: *** [Makefile:969: arch/arm/kernel] Error 2
>> make[1]: *** [package/pkg-generic.mk:292:
>> /home/data/test/buildroot/output/build/linux-custom/.stamp_built] 
>> Error
>> 2
>> make: *** [Makefile:84: _all] Error 2
>> 
>> Full error log is here: https://pastebin.com/VrXqSVsD
> 
> Looking at the error log, it seems like vfp has been selected? But my
> target device only has Features: swp half thumb fastmult edsp java.

This is just a warning, I would ignore it at this point in time. 
Compiler syntax checks tend to get more strict over time ...

> Also, OABI does not seem like it is the correct ABI. For example, if I
> run "file" against the busybox binary the device comes with, I get:
> 
> busybox: ELF 32-bit MSB executable, ARM, EABI5 version 1 (SYSV),
> dynamically linked, interpreter /lib/ld-uClibc.so.0, stripped

It seems to be a compatibility layer for legacy software; disabling 
OABI_COMPAT is an option, because you probably will never need it.

I used the source tree and unmodified .config contained in the 
Touchstone DG3270 Cable Gateway project on SourceForge for the test.

The original build instructions seem to indicate that more software is 
needed to build the device firmware. This might be the reason for 
missing files ...

Also, take a look at psp_drivers.Kconfig for the options necessary to 
enable USB support.

>> 
>> You might now do some research:
>> 
>> https://stackoverflow.com/questions/61235299/gcc-8-3-arm-assembly-
>> error-when-building-linux-kernel-3-14-17-in-buildroot-2020
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85745
>> 
>> or try to switch to an older compiler ...
>> 
>> --
>> Andreas
>> 
>> <cut>