Re: [PATCH v4 2/2] remoteproc: add AMD BRAM-based remote processor driver

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Tue, Jul 07, 2026 at 10:59:55AM +0200, Michal Simek wrote:
> 
> 
> On 7/3/26 18:39, Mathieu Poirier wrote:
> > Hi Ben,
> > 
> > On Mon, Jun 29, 2026 at 09:40:03AM -0700, Ben Levinsky wrote:
> > > Add a remoteproc driver for AMD soft-core processor subsystems
> > > instantiated in programmable logic and using dual-port BRAM for
> > > firmware storage and execution.
> > > 
> > > The driver parses the firmware memory window from the remoteproc device
> > > node's reg property, interprets that address and size in the
> > > processor-local address space, and then uses standard devicetree
> > > address translation through the parent bus ranges property to obtain
> > > the corresponding Linux-visible system physical address.
> > > 
> > > The resulting translated region is registered as the executable
> > > remoteproc carveout and coredump segment.
> > > 
> > > The processor is controlled through an active-low reset GPIO and a
> > > subsystem clock. The clock is enabled before reset is released, and the
> > > processor is kept in reset until firmware loading completes.
> > > 
> > > The firmware-name property is optional, allowing firmware to be
> > > assigned later through the remoteproc framework. Firmware images
> > > without a resource table are also accepted.
> > > 
> > > Signed-off-by: Ben Levinsky <ben.levinsky@amd.com>
> > > ---
> > >   drivers/remoteproc/Kconfig          |  11 ++
> > >   drivers/remoteproc/Makefile         |   1 +
> > >   drivers/remoteproc/amd_bram_rproc.c | 213 ++++++++++++++++++++++++++++
> > >   3 files changed, 225 insertions(+)
> > >   create mode 100644 drivers/remoteproc/amd_bram_rproc.c
> > > 
> > > diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> > > index c521c744e7db..58fa566b609f 100644
> > > --- a/drivers/remoteproc/Kconfig
> > > +++ b/drivers/remoteproc/Kconfig
> > > @@ -23,6 +23,17 @@ config REMOTEPROC_CDEV
> > >   	  It's safe to say N if you don't want to use this interface.
> > > +config AMD_BRAM_REMOTEPROC
> > > +	tristate "AMD BRAM-based remoteproc support"
> > > +	depends on OF && COMMON_CLK && (GPIOLIB || COMPILE_TEST)
> > > +	help
> > > +	  Say y or m here to support a BRAM-based remote processor managed
> > > +	  through the remoteproc framework.
> > > +
> > > +	  The processor is controlled through a reset GPIO and clock.
> > > +
> > 
> > This last sentence doesn't belong here - please remove.
> > 
> > Looking at the bindings and this Kconfig I wonder why the emphasis of the naming
> > convention, i.e "BRAM-based remoteproc" is placed on the kind of memory the
> > remote processor is connected to rather than the remote processor itself.
> > 
> > Wouldn't it be better to have something like "AMD MicroBlaze/V remote
> > processor"?  What happens when we get another AMD softcore that is completely
> > different than MicroBlaze/V that is also connected to the same type of memory?
> > 
> > I'm good with the implemenation, I just wonder about the name...
> 
> We started with very generic amd,bram-proc compatible string and then based
> on discussion
> https://lore.kernel.org/all/20260427162703.1644103-2-ben.levinsky@amd.com/

Thanks for the link, it provides useful context.

> we got recommendation to treat is as soc specific instead of generic.
> Which give us back to origin point if driver should be more soc specific or not.
> 
> I think no issue with AMD prefix.

Agreed.

> 
> BRAM - that's technology used for access. And I see value in symbol to state
> it because access to different memory can be done differently too.
> 

Agreed.

> Shouldn't be there any soc string? This is for zynqmp, versal* SOCs that's
> why hard to choose which one.
> 

Why not just adding a Zynqmp somewhere in there?  But admittedly, the relation
between Zynqmp and MicroBlaze/V is unknown to me.

> The driver is written in very generic way that if there is arm, mips, ppc,
> different risc-v or others access will be the same. Our primary target is
> obviously MicroBlaze/V and I don't think it is a problem to change
> description to just reference them even it is technically possible to
> connect different cpus too.
> 
> Is this enough?
> 
> -	tristate "AMD BRAM-based remoteproc support"
> +	tristate "AMD MicroBlaze/V BRAM-based remoteproc support"

Yes, that would be just fine. "AMD Zynqmp BRAM-based remoteproc support" would
also work.

> 
> Are you fine with AMD_BRAM_REMOTEPROC symbol name?

AMD_MBV_BRAM_REMOTEPROC or AMD_ZQ_BRAM_REMOTEPROC

I'm good with anything that is slightly more descriptive, just pick the one that
makes the most sense.  

> 
> Thanks,
> Michal