Re: [PATCH] rcar-vin: enable field toggle after a set number of lines for Gen3

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Niklas,

Thank you for the patch.

On Wednesday, 25 April 2018 02:56:52 EEST Niklas Söderlund wrote:
> The VIN Gen3 hardware don't have Line Post-Clip capabilities as VIN Gen2
> hardware have. To protect against writing outside the capture window
> enable field toggle after a set number of lines have been captured.
> 
> Capturing outside the allocated capture buffer where observed on R-Car

s/Capturing/Capture/
s/where/has been/

> Gen3 Salvator-XS H3 from the CVBS input if the standard is
> misconfigured. That is if a PAL source is connected to the system but
> the adv748x standard is set to NTSC. In this case the format reported by
> the adv748x is 720x480 and that is what is used for the media pipeline.
> The PAL source generates frames in the format of 720x576 and the field
> is not toggled until the VSYNC is detected and at that time data have
> already been written outside the allocated capture buffer.
> 
> With this change the capture in the situation described above results in
> garbage frames but that is far better then writing outside the capture

s/then/than/

> buffer.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/platform/rcar-vin/rcar-dma.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c
> b/drivers/media/platform/rcar-vin/rcar-dma.c index
> ac07f99e3516a620..b41ba9a4a2b3ac90 100644
> --- a/drivers/media/platform/rcar-vin/rcar-dma.c
> +++ b/drivers/media/platform/rcar-vin/rcar-dma.c
> @@ -124,7 +124,9 @@
>  #define VNDMR2_VPS		(1 << 30)
>  #define VNDMR2_HPS		(1 << 29)
>  #define VNDMR2_FTEV		(1 << 17)
> +#define VNDMR2_FTEH		(1 << 16)
>  #define VNDMR2_VLV(n)		((n & 0xf) << 12)
> +#define VNDMR2_HLV(n)		((n) & 0xfff)
> 
>  /* Video n CSI2 Interface Mode Register (Gen3) */
>  #define VNCSI_IFMD_DES1		(1 << 26)
> @@ -612,8 +614,9 @@ void rvin_crop_scale_comp(struct rvin_dev *vin)
> 
>  static int rvin_setup(struct rvin_dev *vin)
>  {
> -	u32 vnmc, dmr, dmr2, interrupts;
> +	u32 vnmc, dmr, dmr2, interrupts, lines;
>  	bool progressive = false, output_is_yuv = false, input_is_yuv = false;
> +	bool halfsize = false;
> 
>  	switch (vin->format.field) {
>  	case V4L2_FIELD_TOP:
> @@ -628,12 +631,15 @@ static int rvin_setup(struct rvin_dev *vin)
>  		/* Use BT if video standard can be read and is 60 Hz format */
>  		if (!vin->info->use_mc && vin->std & V4L2_STD_525_60)
>  			vnmc = VNMC_IM_FULL | VNMC_FOC;
> +		halfsize = true;
>  		break;
>  	case V4L2_FIELD_INTERLACED_TB:
>  		vnmc = VNMC_IM_FULL;
> +		halfsize = true;
>  		break;
>  	case V4L2_FIELD_INTERLACED_BT:
>  		vnmc = VNMC_IM_FULL | VNMC_FOC;
> +		halfsize = true;
>  		break;
>  	case V4L2_FIELD_NONE:
>  		vnmc = VNMC_IM_ODD_EVEN;
> @@ -676,11 +682,15 @@ static int rvin_setup(struct rvin_dev *vin)
>  		break;
>  	}
> 
> -	/* Enable VSYNC Field Toogle mode after one VSYNC input */
> -	if (vin->info->model == RCAR_GEN3)
> -		dmr2 = VNDMR2_FTEV;
> -	else
> +	if (vin->info->model == RCAR_GEN3) {
> +		/* Enable HSYNC Field Toggle mode after height HSYNC inputs. */
> +		lines = vin->format.height / (halfsize ? 2 : 1);
> +		dmr2 = VNDMR2_FTEH | VNDMR2_HLV(lines);
> +		vin_dbg(vin, "Field Toogle after %u lines\n", lines);
> +	} else {
> +		/* Enable VSYNC Field Toogle mode after one VSYNC input. */
>  		dmr2 = VNDMR2_FTEV | VNDMR2_VLV(1);
> +	}
> 
>  	/* Hsync Signal Polarity Select */
>  	if (!(vin->mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))

-- 
Regards,

Laurent Pinchart