u-boot 32-bit on Raspberry Pi 4

[Alexander von Gluck IV]

January 17, 2020 7:59 PM, "Jaehoon Chung" <jh80.chung at samsung.com> wrote:
> On 1/18/20 10:53 AM, Jaehoon Chung wrote:
> 
>> Hi
>> 
>> On 1/18/20 9:22 AM, Alexander von Gluck IV wrote:
>>> Has anyone successfully used u-boot on the Raspberry Pi 4 in 32-bit mode?
>> 
>> I'm using 32-bit u-boot on RPI4 board with Tizen Platform.
>> You can refer to tizen u-boot git. Also I modified some configurations.
>> 
>> https://protect2.fireeye.com/url?k=d4848ff3-8957d64d-d48504bc-0cc47a31ba82-40c2c54dba31c6f3&u=https:
>> /git.tizen.org/cgit/platform/kernel/u-boot/log/?h=tizen
>>
>> enable_uart=1
>> uart_2ndstage=1

uart_2ndstate=1 helped a lot :-)

I have it figured out now.

I wasn't aware of the change around Raspberry Pi's FDT's needing to
be on the boot partition for start4.elf.

All of our existing bootloader code depends on the FDT embedded
into u-boot.  (fdtcontroladdr, see below for our boot.scr)

Does u-boot "pick-up" the FDT from the Pi foundation's start4.elf and place it at fdtcontroladdr?


test -e mmc 0 uEnv.txt && fatload mmc 0 ${scriptaddr} uEnv.txt && env import -t ${scriptaddr} ${filesize} \
                fatload mmc 0 ${kernel_addr_r} haiku_loader.ub \
                fatload mmc 0 ${ramdisk_addr_r} haiku_floppyboot.ub \
                env exists dtb && fatload mmc 0 ${fdt_addr_r} ${dtb} && fdt addr ${fdt_addr_r} && bootm ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r} \
                fdt addr ${fdtcontroladdr} && bootm ${kernel_addr_r} ${ramdisk_addr_r} ${fdtcontroladdr}"


I thought the FDT embedded into u-boot was the "best way" to get it :-|

 -- Alex