Re: [PATCH edk2-platforms 1/2] Silicon/SynQuacer/PlatformDxe: set NETSEC DMA as coherent

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

On Thu, 28 Nov 2019 at 15:56, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>
> On Thu, Nov 28, 2019 at 15:48:39 +0100, Ard Biesheuvel wrote:
> > We switched to cache coherent DMA for the NETSEC network controller ages
> > ago, but the platform driver that registers the non-discoverable device
> > currently does not reflect this change, which we haven't noticed since
> > the driver doesn't look at this flag.
>
> Should the drive look at this flag?
>

The driver links against DmaLib, so it is either built for coherent
DMA only, or for non-coherent DMA only. This is different from the
eMMC on this platform, since it uses NonDiscoverablePciDeviceDxe,
which implements support for both coherent and non-coherent DMA in the
same driver, so there it has to be accurate or things break. For
NETSEC, we could add a check I suppose, but it is certainly not a high
prio thing imo.

> > Let's fix this nonetheless, in case it ever matters.
> >
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> This patch clearly makes sense anyway, so:
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>

Thanks

>
> > ---
> >  Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
> > index 73cc560fa8d8..57f8fa90343a 100644
> > --- a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
> > +++ b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.c
> > @@ -130,7 +130,7 @@ RegisterDevice (
> >    }
> >
> >    Device->Type = TypeGuid;
> > -  Device->DmaType = NonDiscoverableDeviceDmaTypeNonCoherent;
> > +  Device->DmaType = NonDiscoverableDeviceDmaTypeCoherent;
> >    Device->Resources = Desc;
> >
> >    Status = gBS->InstallMultipleProtocolInterfaces (Handle,
> > --
> > 2.20.1
> >