[PATCH] spl: Add function called after fpga image upload

[Simon Glass]

Hi,

On Mon, 10 Jul 2023 at 09:15, Taedcke, Christian
<christian.taedcke-oss at weidmueller.com> wrote:
>
>
>
> Am 10.07.2023 um 15:44 schrieb Marek Vasut:
> > On 7/10/23 15:02, Taedcke, Christian wrote:
> >> Am 10.07.2023 um 13:41 schrieb Michal Simek:
> >>>
> >>>
> >>> On 6/27/23 11:04, christian.taedcke-oss at weidmueller.com wrote:
> >>>> From: Christian Taedcke <christian.taedcke at weidmueller.com>
> >>>>
> >>>> This way custom logic can be implemented per board after the fpga
> >>>> image is uploaded.
> >>>
> >>> What do you want to do there?
> >>
> >> I have 2 use-cases for this:
> >> 1. Clear the RAM which contained the bitstream (memset to zero). This
> >> should happen independed of the result of the upload operation.
> >
> > Is this some "secure-boot" related item ?
>
> Not directly. This only helps reducing the time the decrypted bitstream
> is stored in RAM.
>
> >
> >> 2. Control a LED based on the upload result. So in case the upload
> >> failed, i want to enable some error LED.
> >>
> >> One issue is that the return values of spl_fit_load_fpga() or
> >> spl_fit_upload_fpga() are not evaluated in common/spl
> >> /spl_fit.c. So this error is not propagated to higher layers.
> >>
> >> I my use-case uploading the bitstream is mandatory before starting
> >> u-boot.
> >>
> >>>
> >>> I expect Simon won't like that it is another weak function.
> >>
> >> I did not find another way to implement the above use-cases. Maybe i
> >> missed something.
> >
> > Based on the above, probably make a weak wrapper around the fpga_load()
> > call, make it call fpga_load() by default and override it in some board
> > specific manner if needed.
>
> So instead of the implemented function in this patch, i add
>
> __weak int fpga_load_wrapper(int devnum, const void *buf, size_t bsize,
>                              bitstream_type bstype, int flags) {
>         return fpga_load(devnum, buf, bsize, bstype, flags);
> }
>
> in the file common/spl/spl_fit.c and call this instead of fpga_load()?
>
> This way only the logic for loading the fpga bitstream in the spl from a
> fit image would change, but not anywhere else (which is ok for me).

Firstly we should not be using devnum but a struct udevice. Really the
FPGA subsystem needs to be converted to use drivel model properly.

But anyway, could you use an event? [1]

Then you can write:

   event_notify_null(EVT_FPGA_LOAD);

and the event spy (if any) can do what is needed. You can add
parameters to the event too.

Regards,
Simon

[1] https://u-boot.readthedocs.io/en/latest/develop/event.html