Re: [PATCH v5 16/29] media: rockchip: rga: split flip and rotate into separate function

[Nicolas Dufresne <nicolas@ndufresne.ca>]

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Le mardi 28 avril 2026 à 11:00 +0200, Sven Püschel a écrit :
> Split the flip and rotate command configuration into a separate
> function in preparation of filling the command stream at streamon.
> As the userspace can change the flipping and rotation controls while
> streaming, we have to update them with each new frame to prevent the
> user being unable to change them while streaming.
> 
> Signed-off-by: Sven Püschel <s.pueschel@pengutronix.de>

For code point of view, everything seems fine, but the commit message leave me a
bit wondering. Any rotation that isn't 180 degree will cause the width and
height to be reversed, and a new stride is needed to present the buffer
correctly. Meaning the capture format can be affected by this change.

To stick with the spec, the capture format needs to be updated, and it needs to
happen in a way user can be able to read it back for the correct frame if
userspace make use of the queues. I see 3 options, let me know what you think,
or what is later implemented if you already thought about that.

1. Synchronously update the capture format width/height, document in the
respective control this behaviour, leaving to userspace to remember which frames
the change will apply to.

This works nicely for this type of HW, but would be a bit complicated for a
deinterlacer, since the buffering might be HW specific. It also make usage of
queues harder, less independent.

2. Force a drain/stop/start for any 90 degree rotation

This might impose a longer idle time for the converter core, and is kind of
opposite of your commit message. But requires no spec work.

3. Emit SRC_CH, implement the drain procedure typical to decoder resolution
change.

Typically it means userspace can keep buffering on the OUTPUT queue, and once
the LAST buffer is met, it can simply read the new format (and new stride, since
due to alignment, this might be hardware specific) and toggle streamoff/on only
on capture queue to reactivate the processing.

The 3. is more complex for the driver, but its a proven race-free method for
decoders already. 2 would be statusquo to get this series in, and we could post-
poned more advance work for seamless 90degree rorations. 1., I don't really like
that solution, it not quite generic enough.

feedback welcome,
Nicolas

> ---
>  drivers/media/platform/rockchip/rga/rga-hw.c | 57 +++++++++++++++++-----------
>  1 file changed, 34 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga-hw.c b/drivers/media/platform/rockchip/rga/rga-hw.c
> index dac3cb6aa17d3..6c1956b04f6ba 100644
> --- a/drivers/media/platform/rockchip/rga/rga-hw.c
> +++ b/drivers/media/platform/rockchip/rga/rga-hw.c
> @@ -156,7 +156,38 @@ static void rga_cmd_set_dst_addr(struct rga_ctx *ctx, dma_addr_t dma_addr)
>  	dest[reg >> 2] |= 0x7 << 8;
>  }
>  
> -static void rga_cmd_set_trans_info(struct rga_ctx *ctx)
> +static void rga_cmd_set_flip_rotate_info(struct rga_ctx *ctx)
> +{
> +	u32 *dest = ctx->cmdbuf_virt;
> +	union rga_src_info src_info;
> +
> +	src_info.val = dest[(RGA_SRC_INFO - RGA_MODE_BASE_REG) >> 2];
> +
> +	if (ctx->vflip)
> +		src_info.data.mir_mode |= RGA_SRC_MIRR_MODE_X;
> +
> +	if (ctx->hflip)
> +		src_info.data.mir_mode |= RGA_SRC_MIRR_MODE_Y;
> +
> +	switch (ctx->rotate) {
> +	case 90:
> +		src_info.data.rot_mode = RGA_SRC_ROT_MODE_90_DEGREE;
> +		break;
> +	case 180:
> +		src_info.data.rot_mode = RGA_SRC_ROT_MODE_180_DEGREE;
> +		break;
> +	case 270:
> +		src_info.data.rot_mode = RGA_SRC_ROT_MODE_270_DEGREE;
> +		break;
> +	default:
> +		src_info.data.rot_mode = RGA_SRC_ROT_MODE_0_DEGREE;
> +		break;
> +	}
> +
> +	dest[(RGA_SRC_INFO - RGA_MODE_BASE_REG) >> 2] = src_info.val;
> +}
> +
> +static void rga_cmd_set_format_scale_info(struct rga_ctx *ctx)
>  {
>  	struct rockchip_rga *rga = ctx->rga;
>  	u32 *dest = ctx->cmdbuf_virt;
> @@ -219,27 +250,6 @@ static void rga_cmd_set_trans_info(struct rga_ctx *ctx)
>  		}
>  	}
>  
> -	if (ctx->vflip)
> -		src_info.data.mir_mode |= RGA_SRC_MIRR_MODE_X;
> -
> -	if (ctx->hflip)
> -		src_info.data.mir_mode |= RGA_SRC_MIRR_MODE_Y;
> -
> -	switch (ctx->rotate) {
> -	case 90:
> -		src_info.data.rot_mode = RGA_SRC_ROT_MODE_90_DEGREE;
> -		break;
> -	case 180:
> -		src_info.data.rot_mode = RGA_SRC_ROT_MODE_180_DEGREE;
> -		break;
> -	case 270:
> -		src_info.data.rot_mode = RGA_SRC_ROT_MODE_270_DEGREE;
> -		break;
> -	default:
> -		src_info.data.rot_mode = RGA_SRC_ROT_MODE_0_DEGREE;
> -		break;
> -	}
> -
>  	/*
>  	 * Calculate the up/down scaling mode/factor.
>  	 *
> @@ -431,7 +441,8 @@ static void rga_cmd_set(struct rga_ctx *ctx,
>  
>  	rga_cmd_set_src_info(ctx, &src->offset);
>  	rga_cmd_set_dst_info(ctx, &dst->offset);
> -	rga_cmd_set_trans_info(ctx);
> +	rga_cmd_set_format_scale_info(ctx);
> +	rga_cmd_set_flip_rotate_info(ctx);
>  
>  	rga_write(rga, RGA_CMD_BASE, ctx->cmdbuf_phy);
>  

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