Re: [PATCH v6 00/12] dma-buf: heaps: Add support for Tegra VPR

Hi Thierry,

On Fri, Sep 04, 2026 at 12:44:51PM +0200, Thierry Reding wrote:

This series adds support for the video protection region (VPR) used on
Tegra SoC devices. It's a special region of memory that is protected
from accesses by the CPU and used to store DRM protected content (both
decrypted stream data as well as decoded video frames).

Patches 1 through 3 add DT binding documentation for the VPR and add the
VPR to the list of memory-region items for display, host1x and NVDEC.

The set_direct_map_*_noflush() functions that will be used later in this
series are exported in patch 4 so that the drivers that use them can be
built as a module.

Patch 5 adds bitmap_allocate(), which is like bitmap_allocate_region()
but works on sizes that are not a power of two.

The of_node_to_nid() function is exported in patch 6 because it is used
in a later patch adding a driver that can be built as a module.

Patch 7 introduces new APIs needed by the Tegra VPR implementation that
allow memory to be allocated at a fixed offset within a CMA area. Tegra
VPR needs this in order to implement its own allocator on top of CMA to
meet the strict hardware requirements. This replaces the dynamic CMA
area creation patch from earlier versions.

Did you get a chance to see how this could work with Vincent's series:

https://lore.kernel.org/r/20260902104712.2399797-1-vdonnefort@google.com (local)

? I think that should remove your reliance on can_set_direct_map() and
mean that you can retain block mappings for most of the linear mapping.

Looks like you forgot to cc him, so I added him here.

Cheers,

Will