Re: [PATCH 5/5] spi: cadence-xspi: Add workaround for old Marvell firmwares

[Paul Cercueil <paul.cercueil@bootlin.com>]

Hi Mark,

Le samedi 07 novembre 2026 à 21:21 +0800, Jisheng Zhang a écrit :
> On Wed, Nov 04, 2026 at 11:06:43AM +0100, Paul Cercueil wrote:
> > From: Tanmay Jagdale <tanmay@marvell.com>
> > 
> > Older firmwares from Marvell used the cdns,xspi-nor compatible string
> > for the Marvell-specific xSPI IP, which is incompatible.
> > 
> > Add a workaround to support this by assuming that if the "xfer" resource
> > is found, it means that a Marvell IP is used.
> > S> 
> > Signed-off-by: Tanmay Jagdale <tanmay@marvell.com>
> > Co-developed-by: Paul Cercueil <paul.cercueil@bootlin.com>
> > Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
> > ---
> >  drivers/spi/spi-cadence-xspi.c | 18 ++++++++++++++----
> >  1 file changed, 14 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
> > index 48a109f3fcdb..d326589a6ca3 100644
> > --- a/drivers/spi/spi-cadence-xspi.c
> > +++ b/drivers/spi/spi-cadence-xspi.c
> > @@ -1301,11 +1301,21 @@ static int cdns_xspi_probe(struct platform_device
> > *pdev)
> >  	}
> >  
> >  #ifdef CONFIG_64BIT
> > -	if (cdns_xspi->driver_data->mrvl_hw_overlay) {
> > -		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > "xfer");
> > -		if (!res)
> > -			res = platform_get_resource(pdev, IORESOURCE_MEM,
> > 3);
> > +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xfer");
> > +	if (!res)
> > +		res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
> 
> This moves the mrvl specific code to all users, so I believe this
> needs dt-binding update.

I actually disagree here. The binding says that "xfer" is only provided with
Marvell-specific compatible strings, and that's correct. The fact that some
firmwares don't respect this spec is not a problem of the spec itself.

> From another side, this assumes other users doesn't have 4th resource
> but what about if they have? they will get "Marvell-specific xfer
> resource passed, but ..." warning below, this confuse the users.
> I don't think this workaround can be added to all users.

Yes, I thought about that and I can understand that you don't like it...

I originally thought that it was fine because the dt-binding states that the 4th
resource is only for Marvell compatibles; but the binding can change, so it's a
bit wobbly.

I will come up with a better mechanism in the v2.

> Lastly, does the "firmware" mean dtb? But per my grep, I didn't
> find any mrvl dts(i) uses "cdns,xspi-nor" compatible string, so
> this means the dtb is outside upstream, then can the firmware
> be fixed instead?

It is dtb and also ACPI. The firmware can and will be fixed, the idea here is to
make sure that the driver still works on older firmwares that haven't been
updated yet, because they are out there.

Cheers,
-Paul