Re: [PATCH v5 00/10] media: Add support for Broadcom/RPi BCM2835 ISP

[Dave Stevenson]

Hi Jai and All.

On Thu, 17 Sept 2026 at 09:25, Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> This series adds initial support for Broadcom/Raspberry Pi BCM2835 ISP
> present on older Raspberry Pi boards.
>
> The underlying hardware for the ISP is accessed through the VideoCore
> VPU, via the VCHIQ/MMAL interface that was recently destaged under
> platform/raspberrypi. The ISP driver, and thus this series, depends on
> VCSM CMA driver for shared memory support (for lens shading buffers):
>
> https://lore.kernel.org/all/20260916-b4-vc-sm-cma-v4-0-476d1142b5df@xxxxxxxxxxxxxxxx
>
> The baseline driver was taken from the one present in the downstream
> raspberrypi 6.12 tree (which was posted as v1 with minor cleanups).
>
> Since then the driver has been significantly modified, switching away
> from custom V4L2 controls to parameter buffers for ISP configuration,
> and many other fixes.
>
> This series along with dependencies is available for ease of testing in
> this linux branch:
> https://github.com/jailuthra/linux/tree/b4/rpi-isp
>
> You can test this series with libcamera, using the following libcamera
> branch:
> https://github.com/jailuthra/libcamera/tree/pi4-upstream
>
> This series (v4 onwards) depends on the latest raspberry pi firmware
> that is in process of being published. I'll reply with a link to this
> cover letter when it's available.

Apologies, I hadn't nudged the relevant person for it to be released.
It is now in https://github.com/raspberrypi/rpi-firmware

  Dave

> Thanks,
> Jai
>
> Signed-off-by: Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx>
> ---
> Changes in v5:
> - Add missing note in cover letter about dependency on latest firmware
> - Update documentation of return type of vb2_core_expbuf_dmabuf() to only
>   ERR_PTR and not NULL
> - Fix warnings reported by media-ci (coccinelle, smatch etc.)
>   - Use struct_group() around the fields we want to memcpy from UAPI param
>     struct to the anonymous structs inside mmal_parameter_isp_parameters
>   - Don't use complicated pointer arithmetic and instead write
>     mmal_param->_mmal_substruct.update = 1 explicitly
>   - Only check for IS_ERR and not IS_ERR_OR_NULL for output of
>     vb2_core_expbuf_dmabuf()
>   - Check node->id against array bounds
> - Link to v4: https://lore.kernel.org/r/20260916-b4-vchiq-isp-v4-0-f668c2017b74@xxxxxxxxxxxxxxxx
>
> Changes in v4:
> - Rebase on v7.3-rc1
> - Set ISP_NUM_INSTANCES to 1 until we have proper support for
>   multiplexing ISP instances (Laurent)
> - Add a new struct mmal_parameter_isp_parameters {} in mmal-parameters.h
>   to send combined updates the firmware (Dave)
> - Rework bcm2835-isp-params.c to use the above and save expensive
>   messages over IPC boundary (Dave)
> - Test if the firmware supports the single struct, and fail with an
>   error message asking the user to update their firmware if not (Dave)
> - Check for retval of isp_set_param() and print error messages if it
>   fails
> - Various cleanups and suggestions (Paul)
> - Add "media: videobuf2-core: Move type check out of vb2_core_expbuf()"
>   on Laurent's suggestion
> - Drop comment about FourCC values being copied from V4L2
> - Drop old paragraph in Kconfig that got copied from previous revision
> - Link to v3: https://lore.kernel.org/r/20260717-b4-vchiq-isp-v3-0-fb8235e15c68@xxxxxxxxxxxxxxxx
>
> Changes in v3:
> - Rebase on v7.2-rc1
> - Split PATCH 1 to add missing incles before moving the headers
> - Update commit messages with Laurent's suggestions
> - Drop redundant buffer list and locks for params as we send them
>   immediately to the firmware in .buf_queue
> - Drop the now empty .stop_streaming() for params node
> - Minor cleanups
> - Link to v2: https://lore.kernel.org/r/20260210-b4-vchiq-isp-v2-0-4403944152fe@xxxxxxxxxxxxxxxx
>
> Changes in v2:
> - Replace custom V4L2 controls (V4L2_CID_USER_BCM2835_ISP_*) with the
>   V4L2 extensible parameters framework via a dedicated metadata output
>   node (bcm2835-isp-params). Split params handling into new file
>   bcm2835-isp-params.c.
> - Add AWB gains and digital gain as extensible parameter block types
>   instead of standard V4L2 integer controls.
> - Use MEDIA_ENT_F_PROC_VIDEO_ISP instead of MEDIA_ENT_F_PROC_VIDEO_SCALER
>   for the media entity function.
> - Rework media controller registration: let video device nodes handle
>   their own entity registration, removing the manual entity/interface
>   creation in media_controller_register_node().
> - Propagate colorspace, ycbcr_enc, xfer_func, and quantization properly
>   through g_fmt/s_fmt.
> - Fold the stats/params FourCC additions (previously a separate commit)
>   into this patch.
> - Drop the custom CID base commit (no longer needed).
> - Update documentation.
> - Link to v1: https://lore.kernel.org/r/20260113-b4-vchiq-isp-v1-0-ea0b300bffc8@xxxxxxxxxxxxxxxx
>
> ---
> Dave Stevenson (1):
>       media: videobuf2: Allow exporting of a struct dmabuf
>
> Jai Luthra (7):
>       media: videobuf2-core: Move type check out of vb2_core_expbuf()
>       platform/raspberrypi: vchiq-mmal: Include missing headers
>       platform/raspberrypi: vchiq-mmal: Move headers to include/linux
>       platform/raspberrypi: vchiq-mmal: Support ISP parameters and stats
>       platform/raspberrypi: vchiq-mmal: Support bayer and gray formats
>       platform/raspberrypi: vchiq: Add helpers for vchiq driver data
>       media: platform: broadcom: Move unicam driver to subdir
>
> Naushir Patuck (2):
>       media: platform: broadcom: Add bcm2835-isp driver
>       platform/raspberrypi: vchiq: Load bcm2835_isp driver from vchiq
>
>  Documentation/admin-guide/media/bcm2835-isp.dot    |   14 +
>  Documentation/admin-guide/media/bcm2835-isp.rst    |   78 +
>  Documentation/admin-guide/media/v4l-drivers.rst    |    1 +
>  .../userspace-api/media/v4l/meta-formats.rst       |    1 +
>  .../media/v4l/metafmt-bcm2835-isp.rst              |  101 ++
>  MAINTAINERS                                        |   12 +-
>  drivers/media/common/videobuf2/videobuf2-core.c    |   50 +-
>  drivers/media/common/videobuf2/videobuf2-v4l2.c    |    8 +-
>  drivers/media/dvb-core/dvb_vb2.c                   |    3 +-
>  drivers/media/platform/broadcom/Kconfig            |   18 +-
>  drivers/media/platform/broadcom/Makefile           |    3 +-
>  .../media/platform/broadcom/bcm2835-isp/Kconfig    |   15 +
>  .../media/platform/broadcom/bcm2835-isp/Makefile   |    4 +
>  .../broadcom/bcm2835-isp/bcm2835-isp-common.h      |   50 +
>  .../broadcom/bcm2835-isp/bcm2835-isp-fmts.h        |  558 +++++++
>  .../broadcom/bcm2835-isp/bcm2835-isp-params.c      |  510 +++++++
>  .../broadcom/bcm2835-isp/bcm2835-v4l2-isp.c        | 1516 ++++++++++++++++++++
>  .../media/platform/broadcom/bcm2835-unicam/Kconfig |   18 +
>  .../platform/broadcom/bcm2835-unicam/Makefile      |    3 +
>  .../{ => bcm2835-unicam}/bcm2835-unicam-regs.h     |    0
>  .../broadcom/{ => bcm2835-unicam}/bcm2835-unicam.c |    0
>  drivers/media/v4l2-core/v4l2-ioctl.c               |    2 +
>  .../raspberrypi/vchiq-interface/vchiq_arm.c        |    2 +
>  .../platform/raspberrypi/vchiq-mmal/mmal-vchiq.c   |    9 +-
>  .../linux/raspberrypi}/mmal-common.h               |    4 +
>  .../linux/raspberrypi}/mmal-encodings.h            |   67 +
>  .../linux/raspberrypi}/mmal-msg-common.h           |    0
>  .../linux/raspberrypi}/mmal-msg-format.h           |    0
>  .../linux/raspberrypi}/mmal-msg-port.h             |    0
>  .../linux/raspberrypi}/mmal-msg.h                  |    0
>  .../linux/raspberrypi}/mmal-parameters.h           |  217 +++
>  .../linux/raspberrypi}/mmal-vchiq.h                |    0
>  include/linux/raspberrypi/vchiq_arm.h              |    1 +
>  include/linux/raspberrypi/vchiq_bus.h              |   10 +
>  include/media/videobuf2-core.h                     |   21 +-
>  include/uapi/linux/bcm2835-isp.h                   |  530 +++++++
>  include/uapi/linux/videodev2.h                     |    2 +
>  37 files changed, 3778 insertions(+), 50 deletions(-)
> ---
> base-commit: e5e04726cdd043e309677071ab1b65a4b18f422b
> change-id: 20250923-b4-vchiq-isp-7e8c22c2860c
> prerequisite-change-id: 20251030-b4-vc-sm-cma-f6727c39cd25:v4
> prerequisite-patch-id: 4fc8cb49edcbe9c8e699b4ab9f6863ac040a070b
> prerequisite-patch-id: 0a5fdf8fe23298fac2c6d188e1686dd292901efc
> prerequisite-patch-id: d6d9ee5b60f97112dcf1aea01212c724d9151505
> prerequisite-patch-id: 3855700b608f20e2a6857a9702838d1e54fc31cb
> prerequisite-patch-id: e2b1e84a1e94e7095b964da693129d36dda78bb0
> prerequisite-patch-id: 07e50207cc947f44e1d626b31d0ace7e12a8f3a1
> prerequisite-patch-id: 3d82a2605799686668729fdc2677c3f6b7c2aa0d
> prerequisite-patch-id: 7795536d875736f74fb4b2e77ca106b127bedbc0
> prerequisite-patch-id: ad833b78f90ce3081e470caf70e601fc573bb52d
> prerequisite-patch-id: 1898d91213e9bd75be3109180527fb0caf6d7174
> prerequisite-patch-id: d0cfc49c673c8c4a4c13d44a547104c24f57cb49
>
> Best regards,
> --
> Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx>
>