Re: [PATCH 2/3] media: rkisp1: Add RKISP1_CID_SUPPORTED_PARAMS_BLOCKS control

[Stefan Klug <stefan.klug@ideasonboard.com>]

Hi Laurent,

Thank you for the review.

Quoting Laurent Pinchart (2025-05-22 17:56:41)
> Hi Stefan,
> 
> Thank you for the patch.
> 
> On Thu, May 22, 2025 at 05:08:39PM +0200, Stefan Klug wrote:
> > Add a RKISP1_CID_SUPPORTED_PARAMS_BLOCKS V4L2 control to be able to
> > query the parameters blocks supported by the current kernel on the
> > current hardware from user space.
> > 
> > Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
> > ---
> >  .../platform/rockchip/rkisp1/rkisp1-common.h  |  2 +
> >  .../platform/rockchip/rkisp1/rkisp1-params.c  | 50 ++++++++++++++++++-
> >  include/uapi/linux/rkisp1-config.h            | 10 ++++
> >  include/uapi/linux/v4l2-controls.h            |  6 +++
> >  4 files changed, 67 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > index ca952fd0829b..5f187f9efc7b 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > @@ -415,6 +415,8 @@ struct rkisp1_params {
> >       spinlock_t config_lock; /* locks the buffers list 'params' */
> >       struct list_head params;
> >  
> > +     struct v4l2_ctrl_handler ctrls;
> > +
> >       const struct v4l2_meta_format *metafmt;
> >  
> >       enum v4l2_quantization quantization;
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > index 918eb06c7465..60c9b3c46593 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > @@ -2736,6 +2736,45 @@ static int rkisp1_params_init_vb2_queue(struct vb2_queue *q,
> >       return vb2_queue_init(q);
> >  }
> >  
> > +static int rkisp1_ctrl_init(struct rkisp1_params *params)
> > +{
> > +     int ret;
> > +
> > +     v4l2_ctrl_handler_init(&params->ctrls, 1);
> > +
> > +     struct v4l2_ctrl_config ctrl_config = {
> > +             .id = RKISP1_CID_SUPPORTED_PARAMS_BLOCKS,
> > +             .name = "Supported Params Blocks",
> > +             .type = V4L2_CTRL_TYPE_BITMASK,
> > +             .flags = V4L2_CTRL_FLAG_READ_ONLY,
> > +     };
> 
>         struct v4l2_ctrl_config ctrl_config = {
>                 .id = RKISP1_CID_SUPPORTED_PARAMS_BLOCKS,
>                 .name = "Supported Params Blocks",
>                 .type = V4L2_CTRL_TYPE_BITMASK,
>                 .flags = V4L2_CTRL_FLAG_READ_ONLY,
>         };
>         int ret;
> 
>         v4l2_ctrl_handler_init(&params->ctrls, 1);
> 
> Mixing code and variable declarations is still usually frown upon in the
> kernel.

I thought frown upon is not a no. And as this structure is not yet
complete and is modified afterwards it feels natural to me to put it
close to that place. But I can move it above the function. You decide.

> 
> > +
> > +     for (unsigned int i = 0; i < ARRAY_SIZE(rkisp1_ext_params_handlers); i++) {
> > +             const struct rkisp1_ext_params_handler *block_handler;
> > +
> > +             block_handler = &rkisp1_ext_params_handlers[i];
> > +             ctrl_config.max |= BIT(i);
> > +
> > +             if ((params->rkisp1->info->features & block_handler->features) !=
> > +                 block_handler->features)
> > +                     continue;
> > +
> > +             ctrl_config.def |= BIT(i);
> > +     }
> > +
> > +     v4l2_ctrl_new_custom(&params->ctrls, &ctrl_config, NULL);
> > +
> > +     params->vnode.vdev.ctrl_handler = &params->ctrls;
> > +
> > +     if (params->ctrls.error) {
> > +             ret = params->ctrls.error;
> > +             v4l2_ctrl_handler_free(&params->ctrls);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> >  int rkisp1_params_register(struct rkisp1_device *rkisp1)
> >  {
> >       struct rkisp1_params *params = &rkisp1->params;
> > @@ -2776,10 +2815,16 @@ int rkisp1_params_register(struct rkisp1_device *rkisp1)
> >  
> >       video_set_drvdata(vdev, params);
> >  
> > +     ret = rkisp1_ctrl_init(params);
> > +     if (ret) {
> > +             dev_err(rkisp1->dev, "Control initialization error %d\n", ret);
> > +             goto err_mutex;
> > +     }
> > +
> >       node->pad.flags = MEDIA_PAD_FL_SOURCE;
> >       ret = media_entity_pads_init(&vdev->entity, 1, &node->pad);
> >       if (ret)
> > -             goto err_mutex;
> > +             goto err_ctrl;
> >  
> >       ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
> >       if (ret) {
> > @@ -2792,6 +2837,8 @@ int rkisp1_params_register(struct rkisp1_device *rkisp1)
> >  
> >  err_media:
> >       media_entity_cleanup(&vdev->entity);
> > +err_ctrl:
> > +     v4l2_ctrl_handler_free(&params->ctrls);
> >  err_mutex:
> >       mutex_destroy(&node->vlock);
> >       return ret;
> > @@ -2808,5 +2855,6 @@ void rkisp1_params_unregister(struct rkisp1_device *rkisp1)
> >  
> >       vb2_video_unregister_device(vdev);
> >       media_entity_cleanup(&vdev->entity);
> > +     v4l2_ctrl_handler_free(&params->ctrls);
> >       mutex_destroy(&node->vlock);
> >  }
> > diff --git a/include/uapi/linux/rkisp1-config.h b/include/uapi/linux/rkisp1-config.h
> > index 2d995f3c1ca3..4fc8f221d0c4 100644
> > --- a/include/uapi/linux/rkisp1-config.h
> > +++ b/include/uapi/linux/rkisp1-config.h
> > @@ -1086,6 +1086,9 @@ enum rkisp1_ext_params_block_type {
> >  #define RKISP1_EXT_PARAMS_FL_BLOCK_DISABLE   (1U << 0)
> >  #define RKISP1_EXT_PARAMS_FL_BLOCK_ENABLE    (1U << 1)
> >  
> > +/* A bitmask of parameters blocks supported on the current hardware. */
> > +#define RKISP1_CID_SUPPORTED_PARAMS_BLOCKS   (V4L2_CID_USER_RKISP1_BASE + 0x01)
> > +
> >  /**
> >   * struct rkisp1_ext_params_block_header - RkISP1 extensible parameters block
> >   *                                      header
> > @@ -1520,6 +1523,13 @@ enum rksip1_ext_param_buffer_version {
> >   * V4L2 control. If such control is not available, userspace should assume only
> >   * RKISP1_EXT_PARAM_BUFFER_V1 is supported by the driver.
> >   *
> > + * The read-only V4L2 control ``RKISP1_CID_SUPPORTED_PARAMS_BLOCKS`` can be used
> > + * to query the blocks supported by the current hardware. It contains a bitmask
> 
> s/current hardware/device/
> 
> > + * where each bit represents the availability of the corresponding entry
> > + * from the :c:type:`rkisp1_ext_params_block_type` enum. The max value of the
> > + * control represents the blocks supported by the current kernel (independent of
> > + * the current hardware).
> 
>  * from the :c:type:`rkisp1_ext_params_block_type` enum. The current and default
>  * values of the control represents the blocks supported by the device instance,
>  * while the maximum value represents the blocks supported by the kernel driver,
>  * independently of the device instance.
> 
> I was going to say that the control should be documented in
> Documentation/userspace-api/drivers/rkisp1.rst, but rkisp1-config.h is
> pulled in the documentation tree by
> Documentation/userspace-api/media/v4l/metafmt-rkisp1.rst, so I'm OK with
> this. Hans, Mauro, are you fine as well with documenting the control
> here ?

Looking at the docs, I realized that most people will read the already
existing docs. So creating a completely new file just for the single
control didn't feel good. As you like.

Regards,
Stefan

> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> > + *
> >   * For each ISP block that userspace wants to configure, a block-specific
> >   * structure is appended to the @data buffer, one after the other without gaps
> >   * in between nor overlaps. Userspace shall populate the @data_size field with
> > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> > index 72e32814ea83..f836512e9deb 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -222,6 +222,12 @@ enum v4l2_colorfx {
> >   */
> >  #define V4L2_CID_USER_UVC_BASE                       (V4L2_CID_USER_BASE + 0x11e0)
> >  
> > +/*
> > + * The base for Rockchip ISP1 driver controls.
> > + * We reserve 16 controls for this driver.
> > + */
> > +#define V4L2_CID_USER_RKISP1_BASE            (V4L2_CID_USER_BASE + 0x1220)
> > +
> >  /* MPEG-class control IDs */
> >  /* The MPEG controls are applicable to all codec controls
> >   * and the 'MPEG' part of the define is historical */
> 
> -- 
> Regards,
> 
> Laurent Pinchart
>