[v2] Add support for bcm2711 in vchiq_arm

[PATCH v2 0/2] Add support for bcm2711 in vchiq_arm

Posted by Adrien Thierry 4 years, 2 months ago

The goal of this patch series is to use the bcm2711 compatible string in
vchiq_arm for the Raspberry Pi 4. This allows using the downstream device
tree with the upstream kernel.

---
Changes since v1:
- Removed duplicate compatible string for bcm2711 in
  brcm,bcm2835-vchiq.yaml

Adrien Thierry (2):
  dt-bindings: soc: bcm: bcm2835-vchiq: Add support for bcm2711
  staging: vchiq_arm: Use bcm2711 compatible string for bcm2711-based
    RPi

 .../devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.yaml      | 5 +++++
 arch/arm/boot/dts/bcm2711-rpi.dtsi                           | 1 +
 .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c    | 5 +++++
 3 files changed, 11 insertions(+)


base-commit: ed4643521e6af8ab8ed1e467630a85884d2696cf
-- 
2.35.1

Re: [PATCH v2 0/2] Add support for bcm2711 in vchiq_arm

Posted by Stefan Wahren 4 years, 2 months ago

Hi Adrien,

Am 24.03.22 um 18:26 schrieb Adrien Thierry:
> The goal of this patch series is to use the bcm2711 compatible string in
> vchiq_arm for the Raspberry Pi 4.

there was already a patch series to enable VCHIQ on BCM2711, which 
wasn't accepted:

https://lore.kernel.org/linux-arm-kernel/20211014223230.451659-1-mguma@redhat.com/T/

Could you please explain your approach, especially leaving out 36 bit 
DMA support?

>   This allows using the downstream device
> tree with the upstream kernel.

This is a really bad idea and caused a lot of trouble in the past. A lot 
of the issues in the Fedora or Arch Linux forums or mailing lists 
results from this idea. It wastes the time of the kernel developer since 
these DT files has never been reviewed by the devicetree maintainers.

Best regards

>
> ---
> Changes since v1:
> - Removed duplicate compatible string for bcm2711 in
>    brcm,bcm2835-vchiq.yaml
>
> Adrien Thierry (2):
>    dt-bindings: soc: bcm: bcm2835-vchiq: Add support for bcm2711
>    staging: vchiq_arm: Use bcm2711 compatible string for bcm2711-based
>      RPi
>
>   .../devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.yaml      | 5 +++++
>   arch/arm/boot/dts/bcm2711-rpi.dtsi                           | 1 +
>   .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c    | 5 +++++
>   3 files changed, 11 insertions(+)
>
>
> base-commit: ed4643521e6af8ab8ed1e467630a85884d2696cf

Re: [PATCH v2 0/2] Add support for bcm2711 in vchiq_arm

Posted by Adrien Thierry 4 years, 2 months ago

Hi Stefan,

Thanks for your feedback.

> Could you please explain your approach, especially leaving out 36 bit
> DMA support?

I realize I overlooked this 36 bit DMA support issue, I need to think it
through a little bit more.

> This is a really bad idea and caused a lot of trouble in the past. A lot
> of the issues in the Fedora or Arch Linux forums or mailing lists
> results from this idea. It wastes the time of the kernel developer since
> these DT files has never been reviewed by the devicetree maintainers.

I understand, thanks! I find the downstream dtbs convenient because of the
overlay system that allows you to easily enable certain drivers, but I get
your point.

Best regards,

Adrien