[U-Boot] end-user firmware upgrade

[Wolfgang Denk]

Dear Marcel,

In message <201002012159.29244.korgull at home.nl> you wrote:
> 
> I'm using u-boot for a while now for my AVR (ap7000) project and while happy 
> with it as a developer tool I wonder how I can make it useful for end-user 
> firmware upgrades.
> 
> The way I think about it is that end-user can never be allowed to interact 
> directly with u-boot.  It's something I don't want and the users of my devices 
> also. Unfortunately I can't find anything yet to how I can make it easy for my 
> end-users to upgrade firmware of the device.

I recommend to rethink this attitude. It may be a wise decision not to
require that end users interact with U-Boot for normal operation of
the device, but on the other hand many experienced users consider it a
tremendous advantage if they can get such access if they really want
it.

> 1) Using USB : This is easy for end-users because it doesn't depend on network 
> configuration. Unfortunately there's no USB support in u-boot (at least not for 
> my CPU). I found something at openmoko which may be suitable, but no other 
> valid solutions so far.
> 
> 2) Ethernet : No idea how to do this in an easy way. If it can be done, I'd be 
> happy to hear about it.
> 
> Either way, I have no clue if there are any options in u-boot available 
> already to do what I want or must I implement this from scratch ?

Both has been done before.

Re USB: search for examples of auto_update.c in the U-Boot source
tree - at least 3 boards in mainline support this. Typically U-Boot
will check during the power-on sequence if a USB mass storage device
is plugged in, if this contains a readable file system, checks then
if this contains one or more known image files. Additionally it is
possible to check if the image versions on the USB device are more
recent than those already stored in flash. If all programmed criteria
match, and if the images can be read without error, the content of
the on-board storage (flash, NAND, etc.) gets automatically updated.

Re Network: there is also auto-update support over TFTP; for this you
can tweak the TFTP timeout behaviour with environment variables like
TftpRRQTimeoutMSecs and TftpRRQTimeoutCountMax, see commit e83cc063.
The TFTP auto-update itself is controlled using the environment
variable "updatefile" in combination with config options
CONFIG_UPDATE_TFTP*; for details see commit 4bae9090

Best regards,

Wolfgang Denk

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