[U-Boot] Building u-boot.imx and SPL simultaneously

[Fabio Estevam]

Hi Petr,

On Fri, Sep 2, 2016 at 3:57 PM, Petr Kulhavy <brain at jikos.cz> wrote:
> Hi,
>
> you have already brought it to the point - it needs two defconfigs.
> This means double the files in U-boot and second and more important, how
> does it integrate into a tool like Buildroot?

Buildroot is capable of booting SPL + u-boot.img just fine. Check
wandboard support a reference.

> In other words I'm trying to do it with just one defconfig.
>
> Alltogether I want to build 3 files:
> * SPL which is started by the RBL
> * u-boot.img which is loaded by the SPL from the flash after typing 'c' or
> similar on the terminal
> * u-boot.imx for an initial load of the board via USB if there is no BL at
> all

You don't need u-boot.imx to boot the board with imx_usb_loader.

Check the README update that Stefano did with this commit:

commit 40f4839ce12adfc0223d6e3035cf9c3a4754a0ec
Author: Stefano Babic <sbabic at denx.de>
Date:   Fri Dec 11 17:30:42 2015 +0100

    imx_common: check for Serial Downloader in spl_boot_device

    Check for bmode before reading the boot device
    to check if a serial downloader is started,
    and returns UART if the serial downloader is set,
    letting SPL to wait for an image if
    CONFIG_SPL_YMODEM_SUPPORT is set.

    This allows to load again a SPL based board
    with imx_usb_loader together with a tool
    such as kermit.

    Signed-off-by: Stefano Babic <sbabic at denx.de>
    CC: Tim Harvey <tharvey at gateworks.com>
    CC: Fabio Estevam <Fabio.Estevam at freescale.com>
    CC: Eric Nelson <eric.nelson at boundarydevices.com>
    Reviewed-by: Eric Nelson <eric at nelint.com>
    Tested-by: Eric Nelson <eric at nelint.com>