I am working on a project where I want to create my own embedded linux with U-Boot. Therefore I am working with buildroot, which i recently start learning. After successfully creating my own rasberrypi4_defconfig i am currently struggling at the problem to get u-boot work correctly.
What versions I am working with:
Current State of the work:
I build on a Ubuntu(32bit). I configure buildroot with the raspberrypi4_defconfig and make it without changes. Then i make a u-boot defconfig for rpi_4_32b_defconfig and create the u-boot.bin with make CROSS_COMPILE=arm-linux-gnueabihf- u-boot.bin
Now my next step was to configure the config.txt and exchange the content with following:
enable_uart=1
kernel=u-boot.bin
In addition i copyied my u-boot.bin into my sd-card.
The last step that i actually did is to build my own boot.scr.uimg with following content
mmc dev 0
fatload mmc O:1 ${fdt_addr_r} bcm2711-rpi-4-b.dtb
fatload mmc 0:1 ${kernel_addr_r} zImage
setenv bootargs console=ttyS0,115200 \
root=/dev/mmcblk0p2 rootfstype=ext4 rootwait rw
bootz ${kernel_addr_r} - ${fdt_addr_r}
Problem So far i am archieving to reach the U-boot menu but on booting i get stucked in Starting Kernel I actually thing that my boot.scr.uimg is maybe not correct but dont get it.
Environment
arch=arm
baudrate=115200
board=rpi
board_name=4 Model B
board_rev=0x11
board_rev_scheme=1
board_revision=0xC03111
boot_a_script=load ${devtype} ${devnum}:${distro_bootpart} ${scriptaddr} ${prefix}${script}; source ${scriptaddr}
boot_efi_binary=if fdt addr ${fdt_addr_r}; then bootefi bootmgr ${fdt_addr_r};else bootefi bootmgr ${fdtcontroladdr};fi;load ${devty
pe} ${devnum}:${distro_bootpart} ${kernel_addr_r} efi/boot/bootarm.efi; if fdt addr ${fdt_addr_r}; then bootefi ${kernel_addr_r} ${f
dt_addr_r};else bootefi ${kernel_addr_r} ${fdtcontroladdr};fi
boot_extlinux=sysboot ${devtype} ${devnum}:${distro_bootpart} any ${scriptaddr} ${prefix}${boot_syslinux_conf}
boot_prefixes=/ /boot/
boot_script_dhcp=boot.scr.uimg
boot_scripts=boot.scr.uimg boot.scr
boot_syslinux_conf=extlinux/extlinux.conf
boot_targets=mmc0 mmc1 pxe dhcp
bootargs=console=ttyS0,115200 \
root=/dev/mmcblk0p2 rootfstype=ext4 rootwait rw
bootcmd=run distro_bootcmd
bootcmd_dhcp=if dhcp ${scriptaddr} ${boot_script_dhcp}; then source ${scriptaddr}; fi;setenv efi_fdtfile ${fdtfile}; if test -z "${f
dtfile}" -a -n "${soc}"; then setenv efi_fdtfile ${soc}-${board}${boardver}.dtb; fi; setenv efi_old_vci ${bootp_vci};setenv efi_old_
arch ${bootp_arch};setenv bootp_vci PXEClient:Arch:00010:UNDI:003000;setenv bootp_arch 0xa;if dhcp ${kernel_addr_r}; then tftpboot $
{fdt_addr_r} dtb/${efi_fdtfile};if fdt addr ${fdt_addr_r}; then bootefi ${kernel_addr_r} ${fdt_addr_r}; else bootefi ${kernel_addr_r
} ${fdtcontroladdr};fi;fi;setenv bootp_vci ${efi_old_vci};setenv bootp_arch ${efi_old_arch};setenv efi_fdtfile;setenv efi_old_arch;s
etenv efi_old_vci;
bootcmd_mmc0=devnum=0; run mmc_boot
bootcmd_mmc1=devnum=1; run mmc_boot
bootcmd_pxe=dhcp; if pxe get; then pxe boot; fi
bootdelay=2
bootfstype=fat
cpu=armv7
dhcpuboot=usb start; dhcp u-boot.uimg; bootm
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done
efi_dtb_prefixes=/ /dtb/ /dtb/current/
ethaddr=dc:a6:32:45:1f:d1
fdt_addr=2eff5d00
fdt_addr_r=0x02600000
fdt_high=ffffffff
fdtcontroladdr=3af6ac98
fdtfile=bcm2711-rpi-4-b.dtb
fileaddr=2600000
filesize=9e6f
initrd_high=ffffffff
kernel_addr_r=0x00080000
load_efi_dtb=load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} ${prefix}${efi_fdtfile}
loadaddr=0x00200000
mmc_boot=if mmc dev ${devnum}; then devtype=mmc; run scan_dev_for_boot_part; fi
pxefile_addr_r=0x02500000
ramdisk_addr_r=0x02700000
scan_dev_for_boot=echo Scanning ${devtype} ${devnum}:${distro_bootpart}...; for prefix in ${boot_prefixes}; do run scan_dev_for_extlinux; run scan_dev_for_scripts; done;run scan_dev_for_efi;
scan_dev_for_boot_part=part list ${devtype} ${devnum} -bootable devplist; env exists devplist || setenv devplist 1; for distro_bootpart in ${devplist}; do if fstype ${devtype} ${devnum}:${distro_bootpart} bootfstype; then run scan_dev_for_boot; fi; done; setenv devplist
scan_dev_for_efi=setenv efi_fdtfile ${fdtfile}; if test -z "${fdtfile}" -a -n "${soc}"; then setenv efi_fdtfile ${soc}-${board}${boardver}.dtb; fi; for prefix in ${efi_dtb_prefixes}; do if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${efi_fdtfile}; then run load_efi_dtb; fi;done;if test -e ${devtype} ${devnum}:${distro_bootpart} efi/boot/bootarm.efi; then echo Found EFI removable media binary efi/boot/bootarm.efi; run boot_efi_binary; echo EFI LOAD FAILED: continuing...; fi; setenv efi_fdtfile
scan_dev_for_extlinux=if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${boot_syslinux_conf}; then echo Found ${prefix}${boot_syslinux_conf}; run boot_extlinux; echo SCRIPT FAILED: continuing...; fi
scan_dev_for_scripts=for script in ${boot_scripts}; do if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${script}; then echo Found U-Boot script ${prefix}${script}; run boot_a_script; echo SCRIPT FAILED: continuing...; fi; done
scriptaddr=0x02400000
serial#=10000000f58b842c
soc=bcm283x
stderr=serial,vidconsole
stdin=serial,usbkbd
stdout=serial,vidconsole
usbethaddr=dc:a6:32:45:1f:d1
vendor=raspberrypi
Environment size: 3996/16380 bytes
Boot Log
U-Boot 2020.01-rc4-00066-g7e5ee346fc (Dec 05 2019 - 16:55:27 +0100)
DRAM: 948 MiB
RPI 4 Model B (0xc03111)
MMC: emmc2@7e340000: 0, mmcnr@7e300000: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Net: Net Initialization Skipped
No ethernet found.
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr.uimg
297 bytes read in 18 ms (15.6 KiB/s)
## Executing script at 02400000
switch to partitions #0, OK
mmc0 is current device
40559 bytes read in 29 ms (1.3 MiB/s)
5601344 bytes read in 1084 ms (4.9 MiB/s)
Kernel image @ 0x080000 [ 0x000000 - 0x557840 ]
## Flattened Device Tree blob at 02600000
Booting using the fdt blob at 0x2600000
Using Device Tree in place at 02600000, end 0260ce6e
Starting kernel ...
I had the same confusing problem on raspberry pi 4 and finally I found out solution.
Make sure "enable_uart=1" is in config.txt in first partition.
Raspberry pi 4 supports both 32-bit and 64-bit mode. The firmware config.txt, u-boot and kernel should be same configuration.
Here is my config.txt for 64-bit system.
[pi4]
kernel=u-boot.bin
max_framebuffers=2
[all]
arm_64bit=1
enable_uart=1
dtparam=i2c=on
dtparam=spi=on
dtparam=act_led_trigger=heartbeat
dtparam=pwr_led_trigger=mmc0
dtparam=audio=on
device_tree_address=0x02000000
dtoverlay=vc4-fkms-v3d,cma-128
Just remove "arm_64bit=1" for 32-bit system, working with 32-bit u-boot and kernel and device tree binary (dtb).
Please make sure you're using correct toolchain for each system.
Here is my toolchain for u-boot, kernel and buildroot:
64-bit: gcc-linaro-7.5.0-2019.12-x86_64_aarch64-linux-gnu
32-bit: gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf
Here is my bootargs to load rootfs on second partition.
setenv bootargs 8250.nr_uarts=1 console=ttyS0,115200 root=/dev/mmcblk0p2 rootwait rw
For 64-bit system
fatload mmc 0:1 ${kernel_addr_r} Image
fatload mmc 0:1 ${fdt_addr} bcm2711-rpi-4-b.dtb
booti ${kernel_addr_r} - ${fdt_addr}
For 32-bit system
fatload mmc 0:1 ${kernel_addr_r} zImage
fatload mmc 0:1 ${fdt_addr} bcm2711-rpi-4-b.dtb
bootz ${kernel_addr_r} - ${fdt_addr}
Note that we need use fdt_addr instead of fdt_addr_r, although fdt_addr_t also works for me. See https://elinux.org/RPi_U-Boot for fdt_addr vs fdt_addr_t.