[U-Boot] [PATCH] dfu: initial implementation

[Stefan Schmidt]

Hello.

On Thu, 2011-11-03 at 09:44, Andrzej Pietrasiewicz wrote:
> On Wednesday, November 02, 2011 8:30 PM Stefan Schmidt writes:
> > 
> > Agreed. The eMMC flashing with files on FAT is nothing goni specific.
> > Others should be able to use this as well. I see three different parts
> > here that can be separated:
> 
> I agree. Since there is interest in DFU implementation this can and should
> be generalized.

Great!

> > 1) The DFU protocol implementation which lives in usb gadget with an
> > interface for flashing backends
> > 
> > 2) The flashing backends (no idea where to put them best). At the
> > moment that would be the implementation here with eMMC and files on FAT,
> > mine with raw NAND devices and in the future maybe others. Each
> > flashing backend should be generic enough to allow different boards
> > using it.
> > 
> > 3) Board specific information like partitions or hints for the flashing
> > backend. The information itself should be in the board file here and
> > only used by the flashing backends.
> > 
> > How does this sound to you? Andrzej?
> 
> Sounds good to me. In my implementation the interface between dfu gadget
> and flashing backend is around the struct flash_entity.
> It contains a character string intended to provide a human-readable name,
> a void * context which is not interpreted by the gadget code,
> but is passed to the flashing backend and understood by it.
> The struct flash_entity also contains prepare-finish methods
> to be called before and after read/write operations, and the read_block-
> write_block pair. What do you think?

I would need to use it for my NAND backend before I really can comment
on it. I can only tell if I'm happy with and interface if I actually
used it. :)

Will do this when you send it a separate patch with only the DFU
implementation with the flash entity as interface. See my roadmap
proposal in the other mail.

> As far as generalization is concerned, in my flashing backend
> implementation I see these parts as candidates for generalization:
> 
> 1) mbr/ebr reading
> 2) reading/writing mmc
> 3) read/write fat

Agreed. That can be used by all kind of devices.

> 4) generic prepare/finish; not sure if fat-specific prepare can be
> generalized

Would be good to get soem comments on the fs custodians around here.

> 5) read/write_block

Agreed.

> 6) some more work should be put to create an interface between the board
> initialization routine, the flashing backend and the DFU gadget
> implementation.
> In my implementation the board initialization routine calls board-specific
> register_flash_areas, which, in turn, calls DFU gadget's
> register_flash_entities.
> What's your opinion?

The interface between the configuration in the board file and the
actual flashing backend is something I haven't wraped my mind around
yet. Need to think about it.

regards
Stefan Schmidt