[PATCH v2 1/8] dm: fpga: Introduce new uclass

[Alexander Dahl]

Hello Simon,

Am Sun, Sep 25, 2022 at 08:15:38AM -0600 schrieb Simon Glass:
> Hi Michal,
> 
> On Thu, 22 Sept 2022 at 05:45, Michal Simek <michal.simek at amd.com> wrote:
> >
> >
> >
> > On 9/22/22 13:35, Simon Glass wrote:
> > > Hi,
> > >
> > > On Thu, 22 Sept 2022 at 12:27, Michal Simek <michal.simek at amd.com> wrote:
> > >>
> > >>
> > >>
> > >> On 9/21/22 15:22, Alexander Dahl wrote:
> > >>> For future DM based FPGA drivers and for now to have a meaningful
> > >>> logging class for old FPGA drivers.
> > >>>
> > >>> Suggested-by: Michal Simek <michal.simek at amd.com>
> > >>> Signed-off-by: Alexander Dahl <ada at thorsis.com>
> > >>> ---
> > >>>    include/dm/uclass-id.h | 1 +
> > >>>    1 file changed, 1 insertion(+)
> > >>>
> > >>> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> > >>> index a432e43871..c2b15881ba 100644
> > >>> --- a/include/dm/uclass-id.h
> > >>> +++ b/include/dm/uclass-id.h
> > >>> @@ -56,6 +56,7 @@ enum uclass_id {
> > >>>        UCLASS_ETH,             /* Ethernet device */
> > >>>        UCLASS_ETH_PHY,         /* Ethernet PHY device */
> > >>>        UCLASS_FIRMWARE,        /* Firmware */
> > >>> +     UCLASS_FPGA,            /* FPGA device */
> > >>>        UCLASS_FUZZING_ENGINE,  /* Fuzzing engine */
> > >>>        UCLASS_FS_FIRMWARE_LOADER,              /* Generic loader */
> > >>>        UCLASS_GPIO,            /* Bank of general-purpose I/O pins */
> > >>
> > >> Simon: the whole series look good to me. I am happy to take it via my tree when
> > >> you ACK it. Also no problem if you want to take it via your tree.
> > >> Please let me know which way you want to go.
> > >
> > > This is a good step forward but needs a lot more work.
> > >
> > > Please add a uclass file for the FPGA - i.e.
> > > drivers/fpga/fpga-uclass.c - see other such files for examples.
> > >
> > > The FPGA uclass should have methods that match the non-DM interface.
> > > You will likely need a DM_FPGA config to allow enabling the uclass.
> > >
> > > Also this needs a simple sandbox driver/emulator pair, so that it can
> > > be tested, with tests in test/dm/fpga.c that use the driver.
> > >
> > > Admittedly this should have been done ages ago. I vaguely remember
> > > mentioning it at the time, but perhaps I missed it. In any case, all
> > > uclasses must have an API, implementation and tests that run in CI
> > > with sandbox. Testing is a vital part of U-Boot and lack of testing is
> > > the main reason why we went back to the 3-month release cycle.
> >
> > It can be done in steps for sure. Issues which Alex is addressing are there for
> > quite some time and I think we shouldn't gate them by adding requirement to
> > create the whole fpga uclass. It can be done on the top of this series.
> > We know that it has to happen but I wouldn't push Alex to do it as condition for
> > applying this series.
> >  From my perspective if he has time to do, let's start with it. If not it can be
> > done later.
> 
> Well if this is a start, then let's make it a real start. At minimum:
> 
> - add a uclass file with the uclass driver
> - we can skip having any methods for now
> - add a sandbox driver which does nothing
> - add a test which probes the sandbox device
> 
> That is about 50 lines of code and people can then add to it over time.

FWIW, I already did that on the weekend, I just have to look over
it again and maybe give it some polishing before sending.  Draft ist
here:

https://github.com/LeSpocky/u-boot/commit/49efd2a2d0129b977d38340c836bbbb1f080043b

> Without that, I'd rather not have the UCLASS_FPGA.

That's okay I guess.  Will just take me some time, it's not that easy
if you have to learn about DM and UT first, and try it in the end of
the day. ;-)

Greets
Alex

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