Re: [PATCH RFC 04/18] accel/qda: Add built-in compute CB bus for QDA and integrate with IOMMU

[Krzysztof Kozlowski <krzk@kernel.org>]

On 23/02/2026 20:08, Ekansh Gupta wrote:
> Introduce a built-in compute context-bank (CB) bus used by the Qualcomm
> DSP accelerator (QDA) driver to represent DSP CB devices that require
> IOMMU configuration. This separates the CB bus from the QDA driver and
> allows QDA to remain a loadable module while the bus is always built-in.
> 
> A new bool Kconfig symbol DRM_ACCEL_QDA_COMPUTE_BUS is added and is
> selected by the main DRM_ACCEL_QDA driver. The parent accel Makefile is
> updated to descend into the QDA directory for both built-in and module
> builds so that the CB bus is compiled into vmlinux while the driver
> remains modular.
> 
> The CB bus is registered at postcore_initcall() time and is exposed to
> the IOMMU core through iommu_buses[] in the same way as the Tegra
> host1x context-bus. This enables later patches to create CB devices on
> this bus and obtain IOMMU domains for them.
> 
> Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
> ---
>  drivers/accel/Makefile              |  1 +
>  drivers/accel/qda/Kconfig           |  5 +++++
>  drivers/accel/qda/Makefile          |  2 ++
>  drivers/accel/qda/qda_compute_bus.c | 23 +++++++++++++++++++++++
>  drivers/iommu/iommu.c               |  4 ++++
>  include/linux/qda_compute_bus.h     | 22 ++++++++++++++++++++++

Do not combine independent work into one patch.

Also, your patch has clear patch warnings, so please review it BEFORE
you send.

Best regards,
Krzysztof