[U-Boot] [PATCH v1 0/7] imx: add USB Serial Download Protocol (SDP) support

Eric Nelson eric at nelint.com
Sun Aug 6 15:19:04 UTC 2017

Hi Stefan,

On 08/04/2017 04:38 PM, Stefan Agner wrote:
> From: Stefan Agner <stefan.agner at toradex.com>
> This series adds NXP's Serial Download Protocol (SDP) support via
> USB for SPL/U-Boot. It allows to download U-Boot via USB from a
> (recovered) SPL using the same tools used to download SPL itself
> (specifically imx_usb, but also sb_loader seems to work).


> The idea has been brought up when the first targets started to make
> use of SPL for DDR initialization, see:
> https://lists.denx.de/pipermail/u-boot/2015-July/220330.html

There have been lots of discussions surrounding the use of SDP,
and this seems to be a nice alternative to using the i.MX "plugin"
mode that I explored a while back:


> The initial SDP implementation (patch 2) requires the payload to
> have the imx specific headers (hence the move of the imx header
> file in patch 1).
> Patch 3 extends image header support beyond the SDP specification,
> specifically implements also support for U-Boot headers. This
> allows to use the same SPL/U-Boot binaries for recovery as used on
> the regular boot device (SD/eMMC). For that to work also the host
> side imx_usb tools needed an extension, currently available here:
> https://github.com/toradex/imx_loader/tree/imx_usb_batch_mode_refactored
> The full patchset allows to download SPL and U-Boot over USB to a
> target in recovery mode using the same usb_imx utility:


> The usb_imx utility also has a batch mode which allows to download
> multiple artifacts with a single invocation. The details are
> outlined in the imx_usb commit message:
> https://github.com/toradex/imx_loader/commit/5434415d921f1cc4d22332d9558bed6d42db9f60
> In case this patchset gets accepted in U-Boot, I plan to push the
> imx_usb changes upstream as well.

Do you have numbers for how much code/data size this adds to SPL?

I believe some i.MX users have struggled to stay within the
size of internal RAM.



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