Re: [PATCH v5 09/14] media: ti: j721e-csi2rx: add support for processing virtual channels

[Jai Luthra <jai.luthra@ideasonboard.com>]

Quoting Rishikesh Donadkar (2025-08-25 19:55:17)
> From: Jai Luthra <j-luthra@ti.com>
> 
> Use get_frame_desc() to get the frame desc from the connected source,
> and use the provided virtual channel instead of hardcoded one.
> 
> get_frame_desc() returns the same information when called on each stream
> start, so instead get the VCs for all the routed stream at first
> stream start and cache this information in the driver.
> 
> get_frame_desc() works per stream, but as we don't support multiple
> streams yet, we will just always use stream 0. If the source doesn't
> support get_frame_desc(), fall back to the previous method of always
> capturing virtual channel 0.
> 
> Reviewed-by: Yemike Abhilash Chandra <y-abhilashchandra@ti.com>
> Co-developed-by: Pratyush Yadav <p.yadav@ti.com>
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> Signed-off-by: Jai Luthra <j-luthra@ti.com>
> Signed-off-by: Rishikesh Donadkar <r-donadkar@ti.com>
> ---
>  .../platform/ti/j721e-csi2rx/j721e-csi2rx.c   | 108 ++++++++++++++++++
>  1 file changed, 108 insertions(+)
> 
> diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
> index 6cab7642aa10..45e9001fa35b 100644
> --- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
> +++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
> @@ -32,6 +32,7 @@
>  #define SHIM_DMACNTX_YUV422            GENMASK(27, 26)
>  #define SHIM_DMACNTX_DUAL_PCK_CFG      BIT(24)
>  #define SHIM_DMACNTX_SIZE              GENMASK(21, 20)
> +#define SHIM_DMACNTX_VC                        GENMASK(9, 6)
>  #define SHIM_DMACNTX_FMT               GENMASK(5, 0)
>  #define SHIM_DMACNTX_YUV422_MODE_11    3
>  #define SHIM_DMACNTX_SIZE_8            0
> @@ -103,6 +104,7 @@ struct ti_csi2rx_dev;
>  
>  struct ti_csi2rx_ctx {
>         struct ti_csi2rx_dev            *csi;
> +       struct v4l2_subdev_route        *route;
>         struct video_device             vdev;
>         struct vb2_queue                vidq;
>         struct mutex                    mutex; /* To serialize ioctls. */
> @@ -111,6 +113,8 @@ struct ti_csi2rx_ctx {
>         struct media_pad                pad;
>         u32                             sequence;
>         u32                             idx;
> +       u32                             vc;
> +       u32                             stream;
>  };
>  
>  struct ti_csi2rx_dev {
> @@ -134,6 +138,7 @@ struct ti_csi2rx_dev {
>                 dma_addr_t              paddr;
>                 size_t                  len;
>         } drain;
> +       bool                            vc_cached;
>  };
>  
>  static inline struct ti_csi2rx_dev *to_csi2rx_dev(struct v4l2_subdev *sd)
> @@ -614,6 +619,7 @@ static void ti_csi2rx_setup_shim(struct ti_csi2rx_ctx *ctx)
>         }
>  
>         reg |= FIELD_PREP(SHIM_DMACNTX_SIZE, fmt->size);
> +       reg |= FIELD_PREP(SHIM_DMACNTX_VC, ctx->vc);
>  
>         writel(reg, csi->shim + SHIM_DMACNTX(ctx->idx));
>  
> @@ -887,6 +893,83 @@ static void ti_csi2rx_buffer_queue(struct vb2_buffer *vb)
>         }
>  }
>  
> +static int ti_csi2rx_get_route(struct ti_csi2rx_ctx *ctx)
> +{
> +       struct ti_csi2rx_dev *csi = ctx->csi;
> +       struct media_pad *pad;
> +       struct v4l2_subdev_state *state;
> +       struct v4l2_subdev_route *r;
> +
> +       /* Get the source pad connected to this ctx */
> +       pad = media_entity_remote_source_pad_unique(ctx->pad.entity);
> +       if (!pad) {
> +               dev_err(csi->dev, "No pad connected to ctx %d\n", ctx->idx);
> +               v4l2_subdev_unlock_state(state);

Here the state == NULL.

I think this is broken since v4. Please fix in the next one.

> +               return -ENODEV;
> +       }
> +
> +       state = v4l2_subdev_lock_and_get_active_state(&csi->subdev);
> +
> +       for_each_active_route(&state->routing, r) {
> +               if (!(r->flags & V4L2_SUBDEV_ROUTE_FL_ACTIVE))
> +                       continue;
> +               if (r->source_pad != pad->index)
> +                       continue;
> +
> +               ctx->route = r;
> +       }
> +
> +       v4l2_subdev_unlock_state(state);
> +
> +       if (!ctx->route)
> +               return -ENODEV;
> +
> +       return 0;
> +}
> +
> +static int ti_csi2rx_get_vc(struct ti_csi2rx_ctx *ctx)
> +{
> +       struct ti_csi2rx_dev *csi = ctx->csi;
> +       struct ti_csi2rx_ctx *curr_ctx;
> +       struct v4l2_mbus_frame_desc fd;
> +       struct media_pad *source_pad;
> +       struct v4l2_subdev_route *curr_route;
> +       int ret;
> +       unsigned int i, j;
> +
> +       /* Get the frame desc form source */
> +       source_pad = media_entity_remote_pad_unique(&csi->subdev.entity, MEDIA_PAD_FL_SOURCE);
> +       if (!source_pad)
> +               return -ENODEV;
> +
> +       ret = v4l2_subdev_call(csi->source, pad, get_frame_desc, source_pad->index, &fd);
> +       if (ret)
> +               return ret;
> +
> +       if (fd.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2)
> +               return -EINVAL;
> +
> +       for (i = 0; i < csi->num_ctx; i++) {
> +               curr_ctx = &csi->ctx[i];
> +
> +               /* Capture VC 0 by default */
> +               curr_ctx->vc = 0;
> +
> +               ret = ti_csi2rx_get_route(curr_ctx);
> +               if (ret)
> +                       continue;
> +
> +               curr_route = curr_ctx->route;
> +               curr_ctx->stream = curr_route->sink_stream;
> +
> +               for (j = 0; j < fd.num_entries; j++)
> +                       if (curr_ctx->stream == fd.entry[j].stream)
> +                               curr_ctx->vc = fd.entry[j].bus.csi2.vc;
> +       }
> +
> +       return 0;
> +}
> +
>  static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count)
>  {
>         struct ti_csi2rx_ctx *ctx = vb2_get_drv_priv(vq);
> @@ -907,6 +990,25 @@ static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count)
>         if (ret)
>                 goto err;
>  
> +       /* If no stream is routed to this ctx, exit early */
> +       ret = ti_csi2rx_get_route(ctx);
> +       if (ret)
> +               goto err;
> +
> +       /* Get the VC for all enabled ctx on first stream start */
> +       mutex_lock(&csi->mutex);
> +       if (!csi->vc_cached) {
> +               ret = ti_csi2rx_get_vc(ctx);
> +               if (ret == -ENOIOCTLCMD) {
> +                       ctx->vc = 0;
> +               } else if (ret < 0) {
> +                       mutex_unlock(&csi->mutex);
> +                       goto err;
> +               }
> +               csi->vc_cached = true;
> +       }
> +       mutex_unlock(&csi->mutex);
> +
>         ti_csi2rx_setup_shim(ctx);
>  
>         ctx->sequence = 0;
> @@ -953,6 +1055,10 @@ static void ti_csi2rx_stop_streaming(struct vb2_queue *vq)
>         writel(0, csi->shim + SHIM_CNTL);
>         writel(0, csi->shim + SHIM_DMACNTX(ctx->idx));
>  
> +       mutex_lock(&csi->mutex);
> +       csi->vc_cached = false;
> +       mutex_unlock(&csi->mutex);
> +
>         ret = v4l2_subdev_call(&csi->subdev, video, s_stream, 0);
>         if (ret)
>                 dev_err(csi->dev, "Failed to stop subdev stream\n");
> @@ -1306,6 +1412,8 @@ static int ti_csi2rx_init_ctx(struct ti_csi2rx_ctx *ctx)
>  
>         ti_csi2rx_fill_fmt(fmt, &ctx->v_fmt);
>  
> +       ctx->route = NULL;
> +
>         ctx->pad.flags = MEDIA_PAD_FL_SINK;
>         vdev->entity.ops = &ti_csi2rx_video_entity_ops;
>         ret = media_entity_pads_init(&ctx->vdev.entity, 1, &ctx->pad);
> -- 
> 2.34.1
>