Buildroot notes

 

Entry: 2018.02.x downgrading Erlang to 19.3

Date: Sun Mar 25 18:06:10 EDT 2018-2021

 

Make the trivial changes in package/erlang/erlang.mk

Download the tarball to the dl directory manually, and update erlang.hash

 

Maybe easier to go back in buildroot source and copy the old build dir.

 

https://github.com/buildroot/buildroot/tree/2017.11.x/package/erlang

 

 

Doing so creates failures:

 

[email protected]:~/exo/br/target/i586/build/erlang-19.3$ export PATH="/home/tom/exo/br/target/i586/host/bin:/home/tom/exo/br/target/i586/host/sbin:/home/tom/exo/br/target/i586/host/bin:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin:/usr/local/sbin"

[email protected]:~/exo/br/target/i586/build/erlang-19.3$ make cross_check_erl

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

* ERROR:   No usable Erlang/OTP system for the build machine found! Cannot

*          cross compile without such a system.

*

*          Either build a bootstrap system for the build machine, or provide

*          an Erlang/OTP-19 system in the $PATH, and try again. For more

*          information on cross compiling Erlang/OTP-19, see the

*          $ERL_TOP/xcomp/README file.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Makefile:343: recipe for target 'cross_check_erl' failed

make: *** [cross_check_erl] Error 1

 

 

Let's first rebuild the whole thing.  Might be some staile stuff.

 

 

 

Entry: Kernel

Date: Thu May  3 10:59:39 EDT 2018

 

What I want to know.

 

I already have defconfig/savedefconfig setup + the possibility to

customize the buildroot archive itself (patches to package Makefiles).

 

How to create a custom kernel configuration?

 

https://stackoverflow.com/questions/1414968/how-do-i-configure-the-linux-kernel-within-buildroot

 

 

1 configure Linux kernel: make linux-menuconfig

 

2 After leaving menuconfig your configuration will be stored in file:

  output/build/linux-XYZ/.config where XYZ is your kernel version.

 

3 After that you can copy file output/build/linux-*XYZ*/.config to

  board/your_kernel_config/.config

 

4 later in Buildroot menuconfig you can under kernel settings

  configure to use custom kernel config file and enter path:

  board/your_kernel_config/.config

 

 

 

Entry: Tuning sdcard.img

Date: Thu May 17 09:04:00 EDT 2018

 

Partition table seems to be misaligned:

 

# parted /dev/mmcblk0

GNU Parted 3.2

Using /dev/mmcblk0

Welcome to GNU Parted! Type 'help' to view a list of commands.

(parted) unit s                                                          

(parted) p                                                                

Model: SD N1BW1 (sd/mmc)

Disk /dev/mmcblk0: 4016128s

Sector size (logical/physical): 512B/512B

Partition Table: msdos

Disk Flags:

 

Number  Start   End       Size      Type     File system  Flags

 1      1s      32768s    32768s    primary  fat16        boot, lba

 2      32769s  1081344s  1048576s  primary  ext4

 

 

Where is this configured?

 

buildroot/board/beaglebone/genimg.cfg

 

It doesn't specify much for partition table layout.

Looks like this is relevant:

BR2_ROOTFS_POST_IMAGE_SCRIPT="board/beaglebone/post-image.sh"

 

So to customize, copy that script elsewhere and modify it.

   

 

 

Entry: bootloader config

Date: Fri May 18 09:03:33 EDT 2018

 

I want a more straightforward bootloader setup.

 

There is uEnv.txt, but where is all the rest of the config?

 

Where does board_name get set?

 

uboot-2018.01/include/env_default.h

 

#ifdef CONFIG_SYS_BOARD

        "board="        CONFIG_SYS_BOARD                "\0"

        "board_name="   CONFIG_SYS_BOARD                "\0"

#endif

 

[email protected]:~/gw_buildroot/target/bbb/build/uboot-2018.01$ cat u-boot.cfg |grep CONFIG_SYS_BOARD

#define CONFIG_SYS_BOARD "am335x"

 

 

But that's not the same..

=> printenv board_name

board_name=A335BNLT

 

 

EDIT: I can't figure out where this is set.

This means it is clearly too complicated.

 

 

 

Entry: BBB u-boot config

Date: Fri May 18 09:43:08 EDT 2018

 

Can't figure out how this is configured.  uEnv.txt is only part of the story.

 

config/bbb.buildroot has:

 

BR2_TARGET_UBOOT=y

BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y

BR2_TARGET_UBOOT_CUSTOM_VERSION=y

BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2018.01"

BR2_TARGET_UBOOT_BOARD_DEFCONFIG="am335x_evm"

BR2_TARGET_UBOOT_NEEDS_DTC=y

# BR2_TARGET_UBOOT_FORMAT_BIN is not set

BR2_TARGET_UBOOT_FORMAT_IMG=y

BR2_TARGET_UBOOT_SPL=y

BR2_TARGET_UBOOT_SPL_NAME="MLO"

 

[email protected]:~/gw_buildroot/target/bbb/build/uboot-2018.01$ cat configs/am335x_evm_defconfig

 

 

 

I just don't understand where the config is generated eventually.

 

Ok, look into the build directory for

 

[email protected]:~/gw_buildroot/target/bbb/build/uboot-2018.01$ ls -al .*.cmd

-rw-r--r-- 1 tom tom  122 May 17 17:31 .MLO.byteswap.cmd

-rw-r--r-- 1 tom tom   92 May 17 17:31 .MLO.cmd

-rw-r--r-- 1 tom tom   47 May 17 17:31 .u-boot.bin.cmd

-rw-r--r-- 1 tom tom 1527 May 17 17:31 .u-boot.cmd

-rw-r--r-- 1 tom tom   71 May 17 17:31 .u-boot-dtb.bin.cmd

-rw-r--r-- 1 tom tom  394 May 17 17:31 .u-boot-dtb.img.cmd

-rw-r--r-- 1 tom tom  386 May 17 17:31 .u-boot.img.cmd

-rw-r--r-- 1 tom tom  936 May 17 17:31 .u-boot.lds.cmd

-rw-r--r-- 1 tom tom  356 May 17 17:31 .u-boot-nodtb.bin.cmd

-rw-r--r-- 1 tom tom  343 May 17 17:31 .u-boot.srec.cmd

-rw-r--r-- 1 tom tom  126 May 17 17:31 .u-boot.sym.cmd

 

[email protected]:~/gw_buildroot/target/bbb/build/uboot-2018.01$ for f in .*.cmd; do echo "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: $f"; cat $f; done

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .MLO.byteswap.cmd

cmd_MLO.byteswap := ./tools/mkimage -T omapimage -n byteswap -a 0x402F0400 -d spl/u-boot-spl.bin MLO.byteswap  >/dev/null

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .MLO.cmd

cmd_MLO := ./tools/mkimage -T omapimage -a 0x402F0400 -d spl/u-boot-spl.bin MLO  >/dev/null

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.bin.cmd

cmd_u-boot.bin := cp u-boot-dtb.bin u-boot.bin

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.cmd

cmd_u-boot := /brcache/tom/gw_buildroot/target/bbb/host/bin/arm-buildroot-linux-musleabihf-ld.bfd   -pie  --gc-sections -Bstatic  --no-dynamic-linker -Ttext 0x80800000 -o u-boot -T u-boot.lds arch/arm/cpu/armv7/start.o --start-group  arch/arm/cpu/built-in.o  arch/arm/cpu/armv7/built-in.o  arch/arm/lib/built-in.o  arch/arm/mach-omap2/built-in.o  board/ti/am335x/built-in.o  board/ti/common/built-in.o  cmd/built-in.o  common/built-in.o  disk/built-in.o  drivers/built-in.o  drivers/dma/built-in.o  drivers/gpio/built-in.o  drivers/i2c/built-in.o  drivers/mtd/built-in.o  drivers/mtd/nand/built-in.o  drivers/mtd/onenand/built-in.o  drivers/mtd/spi/built-in.o  drivers/net/built-in.o  drivers/net/phy/built-in.o  drivers/pci/built-in.o  drivers/power/built-in.o  drivers/power/battery/built-in.o  drivers/power/domain/built-in.o  drivers/power/fuel_gauge/built-in.o  drivers/power/mfd/built-in.o  drivers/power/pmic/built-in.o  drivers/power/regulator/built-in.o  drivers/serial/built-in.o  drivers/spi/built-in.o  drivers/usb/common/built-in.o  drivers/usb/dwc3/built-in.o  drivers/usb/emul/built-in.o  drivers/usb/eth/built-in.o  drivers/usb/gadget/built-in.o  drivers/usb/gadget/udc/built-in.o  drivers/usb/host/built-in.o  drivers/usb/musb-new/built-in.o  drivers/usb/musb/built-in.o  drivers/usb/phy/built-in.o  drivers/usb/ulpi/built-in.o  env/built-in.o  fs/built-in.o  lib/built-in.o  net/built-in.o  test/built-in.o  test/dm/built-in.o --end-group arch/arm/lib/eabi_compat.o  arch/arm/lib/lib.a -Map u-boot.map;  true

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot-dtb.bin.cmd

cmd_u-boot-dtb.bin := cat u-boot-nodtb.bin dts/dt.dtb > u-boot-dtb.bin

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot-dtb.img.cmd

cmd_u-boot-dtb.img := ./tools/mkimage -f auto -A arm -T firmware -C none -O u-boot -a 0x80800000 -e 0 -n "U-Boot 2018.01"" for am335x board" -E -b arch/arm/dts/am335x-evm.dtb -b arch/arm/dts/am335x-bone.dtb -b arch/arm/dts/am335x-boneblack.dtb -b arch/arm/dts/am335x-evmsk.dtb -b arch/arm/dts/am335x-bonegreen.dtb -b arch/arm/dts/am335x-icev2.dtb -d u-boot-nodtb.bin u-boot-dtb.img  >/dev/null

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.img.cmd

cmd_u-boot.img := ./tools/mkimage -f auto -A arm -T firmware -C none -O u-boot -a 0x80800000 -e 0 -n "U-Boot 2018.01"" for am335x board" -E -b arch/arm/dts/am335x-evm.dtb -b arch/arm/dts/am335x-bone.dtb -b arch/arm/dts/am335x-boneblack.dtb -b arch/arm/dts/am335x-evmsk.dtb -b arch/arm/dts/am335x-bonegreen.dtb -b arch/arm/dts/am335x-icev2.dtb -d u-boot-nodtb.bin u-boot.img  >/dev/null

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.lds.cmd

cmd_u-boot.lds := /brcache/tom/gw_buildroot/target/bbb/host/bin/arm-buildroot-linux-musleabihf-gcc -E -Wp,-MD,./.u-boot.lds.d -D__KERNEL__ -D__UBOOT__   -D__ARM__ -Wa,-mimplicit-it=always  -mthumb -mthumb-interwork  -mabi=aapcs-linux  -mword-relocations  -fno-pic  -mno-unaligned-access  -ffunction-sections -fdata-sections -fno-common -ffixed-r9  -msoft-float   -pipe  -march=armv7-a -D__LINUX_ARM_ARCH__=7  -I./arch/arm/mach-omap2/include -Iinclude    -I./arch/arm/include -include ./include/linux/kconfig.h  -nostdinc -isystem /brcache/tom/gw_buildroot/target/bbb/host/lib/gcc/arm-buildroot-linux-musleabihf/6.4.0/include -ansi -include ./include/u-boot/u-boot.lds.h -DCPUDIR=arch/arm/cpu/armv7  -D__ASSEMBLY__ -x assembler-with-cpp -P -o u-boot.lds board/ti/am335x/u-boot.lds

 

source_u-boot.lds := board/ti/am335x/u-boot.lds

 

deps_u-boot.lds := \

  include/u-boot/u-boot.lds.h \

 

u-boot.lds: $(deps_u-boot.lds)

 

$(deps_u-boot.lds):

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot-nodtb.bin.cmd

cmd_u-boot-nodtb.bin := /brcache/tom/gw_buildroot/target/bbb/host/bin/arm-buildroot-linux-musleabihf-objcopy --gap-fill=0xff  -j .text -j .secure_text -j .secure_data -j .rodata -j .hash -j .data -j .got -j .got.plt -j .u_boot_list -j .rel.dyn -j .binman_sym_table -j .dtb.init.rodata -j .efi_runtime -j .efi_runtime_rel -O binary  u-boot u-boot-nodtb.bin

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.srec.cmd

cmd_u-boot.srec := /brcache/tom/gw_buildroot/target/bbb/host/bin/arm-buildroot-linux-musleabihf-objcopy --gap-fill=0xff  -j .text -j .secure_text -j .secure_data -j .rodata -j .hash -j .data -j .got -j .got.plt -j .u_boot_list -j .rel.dyn -j .binman_sym_table -j .dtb.init.rodata -j .efi_runtime -j .efi_runtime_rel -O srec u-boot u-boot.srec

 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx CMD: .u-boot.sym.cmd

cmd_u-boot.sym := /brcache/tom/gw_buildroot/target/bbb/host/bin/arm-buildroot-linux-musleabihf-objdump -t u-boot > u-boot.sym

 

 

 

Entry: Override full environment?

Date: Fri May 18 10:12:33 EDT 2018

 

I want something similar to this:

https://wiki.beyondlogic.org/index.php?title=BeagleBoneBlack_Default_uBoot_Environment_Variables

 

load mmc 1:2 0x80F80000 /boot/am335x-boneblack.dtb

load mmc 1:2 0x80007fc0 /boot/uImage

setenv bootargs console=ttyO0,115200n8 ${optargs} root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait

bootm 0x80007fc0 - 0x80F80000

 

 

Modified it to:

 

load mmc 0:1 0x80F80000 am335x-boneblack.dtb

load mmc 0:1 0x80007fc0 zImage

setenv bootargs console=ttyS0,115200n8 root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait

bootz 0x80007fc0 - 0x80F80000

 

Which boots the kernel

 

 

so how to overwrite the environment?

 

 

 

Entry: How does it actually work?

Date: Fri May 18 10:35:58 EDT 2018

 

SPL first tries to boot from MMC1, then loads u-boot.img from SD card.

 

 

U-Boot SPL 2018.01 (May 17 2018 - 21:31:43)

Trying to boot from MMC1

*** Warning - bad CRC, using default environment                                                                                                                                

 

reading u-boot.img

reading u-boot.img

reading u-boot.img

reading u-boot.img

 

U-Boot 2018.01 (May 17 2018 - 21:31:43 +0000)

 

CPU  : AM335X-GP rev 2.1

Model: TI AM335x BeagleBone Black

DRAM:  512 MiB

NAND:  0 MiB

MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1

 

 

 

Entry: buildroot pocketbeagle tutorial

Date: Fri May 18 10:47:26 EDT 2018-2021

 

https://bootlin.com/pub/conferences/2018/elc/petazzoni-e-ale-buildroot-tutorial/petazzoni-buildroot-tutorial-lab.pdf

 

This has pocketbeagle patches.  Can I just use a different version

that doesn't need the patches?

 

Let's look at them first.

 

https://github.com/e-ale/buildroot-e-ale

 

Ok, these patches are extensive.  I'm going to wait until they are integrated.