Re: [PATCH 6/7] gpu: nova-core: falcon: allow DMA transfers to read from a framebuffer address

["Eliot Courtney" <ecourtney@nvidia.com>]

On Tue Nov 3, 2026 at 7:22 PM JST, Alexandre Courbot wrote:
> The r000 boot protocol has a load-and-execute event in which GSP-RM asks
> the driver to load a Heavy-Secured binary from framebuffer memory into
> the GSP falcon's memory by DMA in order to run it.
>
> Nova-core's falcon DMA loading method currently only supports loading
> from a DMA object that the driver had allocated, so there is no way to
> copy an image from framebuffer memory that an event supplied.
>
> Address this by making the source of a falcon DMA transfer an enum,
> which can be either a DMA object, or a GPU framebuffer address.
>
> The framebuffer address source has no user yet, but will be used by the
> r000 boot protocol.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---

[...]

> @@ -626,9 +649,13 @@ fn dma_load<F: FalconFirmware<Target = E> + FalconDmaLoadable>(&self, fw: &F) ->
>                      .with_mem_type(FalconFbifMemType::Physical)
>              });
>  

Suggest moving the NV_PFALCON_FBIF_TRANSCFG write into dma_wr because
once we make the source configurable (i.e. allowing vram as a source)
it's now possible to call dma_wr with a bogus NV_PFALCON_FBIF_TRANSCFG
setup with the wrong FalconFbifTarget (but that's determinable from
`FalconDmaSource`).

> -        self.dma_wr(&dma_obj, FalconMem::ImemSecure, fw.imem_sec_load_params())?;
>          self.dma_wr(
> -            &dma_obj,
> +            FalconDmaSource::Sysmem(&dma_obj),
> +            FalconMem::ImemSecure,
> +            fw.imem_sec_load_params(),
> +        )?;
> +        self.dma_wr(
> +            FalconDmaSource::Sysmem(&dma_obj),
>              FalconMem::Dmem { tag: false },
>              fw.dmem_load_params(),
>          )?;