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

[Eric Nelson]

Hi Tom,

On 09/06/2016 06:40 AM, Tom Rini wrote:
> On Fri, Sep 02, 2016 at 10:53:58PM +0200, Petr Kulhavy wrote:
>> Hi Fabio,
>>
>> On 02/09/16 22:03, Fabio Estevam wrote:
>>> 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>
>> This is not particularly what I want to do. I want to load the
>> u-boot.img directly via the imx_usb_loader.
>> The kermit method is unacceptably slow for a production environment.
> 
> Another place this doesn't work (which is where it doesn't work for me)
> is when the console is already open and I can't easily take it away to
> shoot over the next stage via Y-MODEM.
> 
> Would it be possible to implement having the next stage also be sent via
> imx_usb_loader?  ie there's examples today of doing u-boot.imx + kernel
> + initrd via imx_usb_loader, so what would be needed for SPL +
> u-boot.img (+ kenrel + initrd) via imx_usb_loader?  Thanks!
> 

SPL+u-boot.img could be bundled into a single image through the
use of plugins which would require:

- updates to mkimage to support plugins, and
- Makefile updates to produce a third output (u-boot.imx?), and
- an update to SPL startup on i.MX to check for the plugin flag
and return to the boot ROM after startup (instead of loading
U-Boot) if set.

Troy implemented the key bits back in 2012, and I provided
some links here:

http://lists.denx.de/pipermail/u-boot/2016-June/258784.html

Regards,


Eric