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

[Taedcke, Christian]

Hello,

On 10.07.2023 17:47, Simon Glass wrote:
> 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

Thank you for the suggestion. I will prepare a new version of the series 
using an event that is sent from inside fpga_load().

Regards,
Christian