[PATCH v3 16/27] media: rockchip: rga: check scaling factor

[Nicolas Dufresne]

Le mardi 27 janvier 2026 à 15:39 +0100, Sven Püschel a écrit :
> Check the scaling factor to avoid potential problems. This is relevant
> for the upcoming RGA3 support, as it can hang when the scaling factor
> is exceeded.
> 
> There are two relevant scenarios that have to be considered to protect
> against invalid scaling values:
> 
> When the output or capture is already streaming, setting the format on
> the other side should consider the max scaling factor and clamp it
> accordingly. This is only done in the streaming case, as it otherwise
> may unintentionally clamp the value when the application sets the first
> format (due to a default format on the other side).
> 
> When the format is set on both sides first, then the format won't be
> corrected by above means. Therefore the second streamon call has to
> check the scaling factor and fail otherwise.
> 
> As try functions should only be state aware if specified, the scaling
> limitation is only done in s_fmt.
> 
> Signed-off-by: Sven Püschel <s.pueschel at pengutronix.de>
> ---
>  drivers/media/platform/rockchip/rga/rga-hw.c |  1 +
>  drivers/media/platform/rockchip/rga/rga-hw.h |  1 +
>  drivers/media/platform/rockchip/rga/rga.c    | 47 ++++++++++++++++++++++++++++
>  drivers/media/platform/rockchip/rga/rga.h    |  1 +
>  4 files changed, 50 insertions(+)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga-hw.c b/drivers/media/platform/rockchip/rga/rga-hw.c
> index dcd540ed3fd5b..7a4070665fed7 100644
> --- a/drivers/media/platform/rockchip/rga/rga-hw.c
> +++ b/drivers/media/platform/rockchip/rga/rga-hw.c
> @@ -584,6 +584,7 @@ const struct rga_hw rga2_hw = {
>  	.max_width = MAX_WIDTH,
>  	.min_height = MIN_HEIGHT,
>  	.max_height = MAX_HEIGHT,
> +	.max_scaling_factor = MAX_SCALING_FACTOR,
>  	.stride_alignment = 4,
>  
>  	.setup_cmdbuf = rga_hw_setup_cmdbuf,
> diff --git a/drivers/media/platform/rockchip/rga/rga-hw.h b/drivers/media/platform/rockchip/rga/rga-hw.h
> index f4752aa823051..fffcab0131225 100644
> --- a/drivers/media/platform/rockchip/rga/rga-hw.h
> +++ b/drivers/media/platform/rockchip/rga/rga-hw.h
> @@ -14,6 +14,7 @@
>  
>  #define MIN_WIDTH 34
>  #define MIN_HEIGHT 34
> +#define MAX_SCALING_FACTOR 16
>  
>  #define RGA_TIMEOUT 500
>  
> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
> index 6947c472a8b01..fad921ddd8348 100644
> --- a/drivers/media/platform/rockchip/rga/rga.c
> +++ b/drivers/media/platform/rockchip/rga/rga.c
> @@ -405,10 +405,36 @@ static int vidioc_s_fmt(struct file *file, void *priv, struct v4l2_format *f)
>  	struct v4l2_pix_format_mplane *pix_fmt = &f->fmt.pix_mp;
>  	struct rga_ctx *ctx = file_to_rga_ctx(file);
>  	struct rockchip_rga *rga = ctx->rga;
> +	const struct rga_hw *hw = rga->hw;
>  	struct vb2_queue *vq;
>  	struct rga_frame *frm;
>  	int ret = 0;
>  	int i;
> +	struct rga_frame *limit_frm = NULL;
> +
> +	/* Limit before try_fmt to avoid recalculating the stride */
> +	if (V4L2_TYPE_IS_OUTPUT(f->type) &&
> +	    v4l2_m2m_get_dst_vq(ctx->fh.m2m_ctx)->streaming)
> +		limit_frm = &ctx->out;
> +	if (V4L2_TYPE_IS_CAPTURE(f->type) &&
> +	    v4l2_m2m_get_src_vq(ctx->fh.m2m_ctx)->streaming)
> +		limit_frm = &ctx->in;
> +	if (limit_frm) {
> +		const struct v4l2_frmsize_stepwise frmsize = {
> +			.min_width = DIV_ROUND_UP(limit_frm->pix.width,
> +						  hw->max_scaling_factor),
> +			.max_width =
> +				limit_frm->pix.width * hw->max_scaling_factor,
> +			.min_height = DIV_ROUND_UP(limit_frm->pix.height,
> +						   hw->max_scaling_factor),
> +			.max_height =
> +				limit_frm->pix.height * hw->max_scaling_factor,
> +			.step_width = 1,
> +			.step_height = 1,

Is there a risk to re-introduce odd sizes ? Should this be the hdiv / vdiv
values ?

> +		};
> +		v4l2_apply_frmsize_constraints(&pix_fmt->width,
> +					       &pix_fmt->height, &frmsize);
> +	}
>  
>  	/* Adjust all values accordingly to the hardware capabilities
>  	 * and chosen format.
> @@ -568,12 +594,33 @@ static int vidioc_s_selection(struct file *file, void *priv,
>  	return ret;
>  }
>  
> +static bool check_scaling(const struct rga_hw *hw, u32 src_size, u32 dst_size)
> +{
> +	if (src_size < dst_size)
> +		return src_size * hw->max_scaling_factor >= dst_size;
> +	else
> +		return dst_size * hw->max_scaling_factor >= src_size;
> +}
> +
>  static int vidioc_streamon(struct file *file, void *priv,
>  			   enum v4l2_buf_type type)
>  {
>  	struct rga_ctx *ctx = file_to_rga_ctx(file);
>  	const struct rga_hw *hw = ctx->rga->hw;
>  
> +	if ((V4L2_TYPE_IS_OUTPUT(type) &&
> +	     v4l2_m2m_get_dst_vq(ctx->fh.m2m_ctx)->streaming) ||
> +	    (V4L2_TYPE_IS_CAPTURE(type) &&
> +	     v4l2_m2m_get_src_vq(ctx->fh.m2m_ctx)->streaming)) {
> +		/*
> +		 * As the other side is already streaming,
> +		 * check that the max scaling factor isn't exceeded.
> +		 */
> +		if (!check_scaling(hw, ctx->in.pix.width, ctx->out.pix.width) ||
> +		    !check_scaling(hw, ctx->in.pix.height, ctx->out.pix.height))
> +			return -EINVAL;
> +	}
> +
>  	hw->setup_cmdbuf(ctx);
>  
>  	return v4l2_m2m_streamon(file, ctx->fh.m2m_ctx, type);
> diff --git a/drivers/media/platform/rockchip/rga/rga.h b/drivers/media/platform/rockchip/rga/rga.h
> index c741213710b32..454af283b1694 100644
> --- a/drivers/media/platform/rockchip/rga/rga.h
> +++ b/drivers/media/platform/rockchip/rga/rga.h
> @@ -150,6 +150,7 @@ struct rga_hw {
>  	size_t cmdbuf_size;
>  	u32 min_width, min_height;
>  	u32 max_width, max_height;
> +	u8 max_scaling_factor;
>  	u8 stride_alignment;
>  
>  	void (*setup_cmdbuf)(struct rga_ctx *ctx);
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 228 bytes
Desc: This is a digitally signed message part
URL: <http://lists.infradead.org/pipermail/linux-rockchip/attachments/20260320/42ceaca0/attachment.sig>