Re: [PATCH v13 1/3] dt-bindings: perf: Add Broadcom Raspberry Pi AXI PMU definition

On Sun, Aug 16, 2026 at 11:23 PM Krzysztof Kozlowski <[email protected]> wrote:
>
> On 15/08/2026 19:27, Ian Rogers wrote:
> > Add Device Tree bindings for the Broadcom AXI PMU hardware blocks present
> > in the Raspberry Pi SoC line (BCM2835, BCM2711, BCM2712).
> >
> > Depending on the SoC and security configuration, these PMUs support either
> > direct MMIO access or routing via the Raspberry Pi firmware Mailbox IPC.
> > The bindings support defining 1 or 2 backing MMIO regions natively map
> > the system and VPU control surfaces.
> >
> > Assisted-by: Antigravity:gemini-3.6-flash
> > Signed-off-by: Ian Rogers <[email protected]>
> > ---
> >  .../bindings/perf/brcm,bcm2835-axiperf.yaml   | 77 +++++++++++++++++++
> >  1 file changed, 77 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/perf/brcm,bcm2835-axiperf.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/perf/brcm,bcm2835-axiperf.yaml b/Documentation/devicetree/bindings/perf/brcm,bcm2835-axiperf.yaml
> > new file mode 100644
> > index 000000000000..8a4857aa448c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/perf/brcm,bcm2835-axiperf.yaml
> > @@ -0,0 +1,77 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/perf/brcm,bcm2835-axiperf.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Broadcom BCM2835/2711/2712 AXI Performance Monitor
> > +
> > +maintainers:
> > +  - Ian Rogers <[email protected]>
> > +
> > +description: |
> > +  The Broadcom BCM2835 series (including BCM2711 and BCM2712) features hardware
> > +  performance monitors on the AXI bus for evaluating memory bandwidth and
> > +  system traffic. Depending on the SoC architecture, multiple monitors exist.
> > +  The primary
> > +  monitor evaluates the System fabric, while the secondary monitor evaluates the
> > +  VideoCore VPU hardware.
> > +
> > +  Older silicon generally restricts direct MMIO access to the VPU endpoints,
> > +  requiring them to be accessed over the Raspberry Pi firmware mailbox
> > +  interface. If the VPU endpoints are memory-mapped, they are supplied as
> > +  secondary resources.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - brcm,bcm2835-axiperf
> > +      - brcm,bcm2711-axiperf
> > +      - brcm,bcm2712-axiperf
> > +
> > +  reg:
> > +    minItems: 1
> > +    maxItems: 2
> > +    description: |
> > +      Memory-mapped I/O resource regions for the AXI PMU endpoints.
> > +      Typically ordered as System monitor, followed by VPU monitor if directly
> > +      mapped.
> > +
> > +  firmware:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
>
> This was already rejected.
>
> https://lore.kernel.org/all/?q=broadcom+firmware

Ok, assume I'm ignorant of device tree things, how should this be
addressed? Your link is to "~70000" messages.

Thanks,
Ian

> > +    description: |
> > +      Phandle to the Raspberry Pi firmware node. Required on older silicon
> > +      (BCM2835-BCM2711) where VideoCore VPU endpoints are exclusively accessed
> > +      via firmware mailbox IPC.
>
>
> Best regards,
> Krzysztof