[U-Boot] [PATCH 4/4] arm: mvebu: Add runtime detection of UART (xmodem) boot-mode

[Phil Sutter <phil@nwl.cc>]

Hi,

On Sat, Jan 09, 2016 at 10:07:44AM +0100, Stefan Roese wrote:
> This patch adds runtime detection of the Marvell UART boot-mode (xmodem
> protocol). If this boot-mode is detected, SPL will return to the
> BootROM to continue the UART booting.
> 
> With this patch its now possible, to generate a U-Boot image that
> can be booted either from the strapped boot-device (e.g. SPI NOR, MMC,
> etc) or via the xmodem protocol from the UART. In the UART case,
> the kwboot tool will dynamically insert the UART boot-device type
> into the image. And also patch the load address in the header, so
> that the mkimage header will be skipped (as its not expected by the
> Marvell BootROM).
> 
> This simplifies the development for Armada XP / 38x based boards.
> As no special images need to be generated by selecting the
> MVEBU_BOOTROM_UARTBOOT Kconfig option.
> 
> Since the Kconfig option MVEBU_BOOTROM_UARTBOOT is not needed any
> more, its now completely removed.

Really cool approach, but sadly does not work for me. I'm testing UART
boot on my Synology DS414, with this series applied the SPL image runs
as expected and returns to bootrom loader which then continues Xmodem.
At the point where U-Boot should start though, the console is dead.

> -# If the kwboot xmodem protocol is used, to boot U-Boot on the MVEBU
> -# SoC's, the SPL U-Boot returns to the BootROM after it completes
> -# the SDRAM setup. The BootROM expects no U-Boot header in the main
> -# U-Boot image. So we need to combine SPL and u-boot.bin instead of
> -# u-boot.img in this case.
> -ifdef CONFIG_MVEBU_BOOTROM_UARTBOOT
> -u-boot-spl.kwb: u-boot-dtb.bin spl/u-boot-spl.bin FORCE
> -	$(call if_changed,mkimage)
> -else
>  u-boot-spl.kwb: u-boot-dtb.img spl/u-boot-spl.bin FORCE
>  	$(call if_changed,mkimage)
> -endif

This was my first shot and I hit: changing the dependency from
u-boot-dtb.img to u-boot-dtb.bin, U-Boot runs.

Let me know if I can help track the issue down.

Thanks, Phil