[PATCH v6 11/12] media: imx: Allow interweave with top/bottom lines swapped

[Steve Longerbeam <slongerbeam@gmail.com>]

Allow sequential->interlaced interweaving but with top/bottom
lines swapped to the output buffer.

This can be accomplished by adding one line length to IDMAC output
channel address, with a negative line length for the interlace offset.

This is to allow the seq-bt -> interlaced-bt transformation, where
bottom lines are still dominant (older in time) but with top lines
first in the interweaved output buffer.

With this support, the CSI can now allow seq-bt at its source pads,
e.g. the following transformations are allowed in CSI from sink to
source:

seq-tb -> seq-bt
seq-bt -> seq-bt
alternate -> seq-bt

Suggested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---
Changes since v4:
- Removed interweave_offset and replace with boolean interweave_swap,
  suggested by Philipp Zabel.
---
 drivers/staging/media/imx/imx-ic-prpencvf.c | 25 +++++++++----
 drivers/staging/media/imx/imx-media-csi.c   | 40 ++++++++++++++++++---
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/media/imx/imx-ic-prpencvf.c b/drivers/staging/media/imx/imx-ic-prpencvf.c
index cf76b0432371..33ada6612fee 100644
--- a/drivers/staging/media/imx/imx-ic-prpencvf.c
+++ b/drivers/staging/media/imx/imx-ic-prpencvf.c
@@ -106,6 +106,7 @@ struct prp_priv {
 	u32 frame_sequence; /* frame sequence counter */
 	bool last_eof;  /* waiting for last EOF at stream off */
 	bool nfb4eof;    /* NFB4EOF encountered during streaming */
+	bool interweave_swap; /* swap top/bottom lines when interweaving */
 	struct completion last_eof_comp;
 };
 
@@ -235,6 +236,9 @@ static void prp_vb2_buf_done(struct prp_priv *priv, struct ipuv3_channel *ch)
 	if (ipu_idmac_buffer_is_ready(ch, priv->ipu_buf_num))
 		ipu_idmac_clear_buffer(ch, priv->ipu_buf_num);
 
+	if (priv->interweave_swap && ch == priv->out_ch)
+		phys += vdev->fmt.fmt.pix.bytesperline;
+
 	ipu_cpmem_set_buffer(ch, priv->ipu_buf_num, phys);
 }
 
@@ -376,8 +380,9 @@ static int prp_setup_channel(struct prp_priv *priv,
 	 * the IDMAC output channel.
 	 */
 	interweave = V4L2_FIELD_IS_INTERLACED(image.pix.field) &&
-		V4L2_FIELD_IS_SEQUENTIAL(outfmt->field) &&
-		channel == priv->out_ch;
+		V4L2_FIELD_IS_SEQUENTIAL(outfmt->field);
+	priv->interweave_swap = interweave &&
+		image.pix.field == V4L2_FIELD_INTERLACED_BT;
 
 	if (rot_swap_width_height) {
 		swap(image.pix.width, image.pix.height);
@@ -388,6 +393,11 @@ static int prp_setup_channel(struct prp_priv *priv,
 			(image.pix.width * outcc->bpp) >> 3;
 	}
 
+	if (priv->interweave_swap && channel == priv->out_ch) {
+		/* start interweave scan at 1st top line (2nd line) */
+		image.rect.top = 1;
+	}
+
 	image.phys0 = addr0;
 	image.phys1 = addr1;
 
@@ -396,8 +406,8 @@ static int prp_setup_channel(struct prp_priv *priv,
 	 * channels for planar 4:2:0 (but not when enabling IDMAC
 	 * interweaving, they are incompatible).
 	 */
-	if (!interweave && (channel == priv->out_ch ||
-			    channel == priv->rot_out_ch)) {
+	if ((channel == priv->out_ch && !interweave) ||
+	    channel == priv->rot_out_ch) {
 		switch (image.pix.pixelformat) {
 		case V4L2_PIX_FMT_YUV420:
 		case V4L2_PIX_FMT_YVU420:
@@ -424,8 +434,11 @@ static int prp_setup_channel(struct prp_priv *priv,
 	if (rot_mode)
 		ipu_cpmem_set_rotation(channel, rot_mode);
 
-	if (interweave)
-		ipu_cpmem_interlaced_scan(channel, image.pix.bytesperline,
+	if (interweave && channel == priv->out_ch)
+		ipu_cpmem_interlaced_scan(channel,
+					  priv->interweave_swap ?
+					  -image.pix.bytesperline :
+					  image.pix.bytesperline,
 					  image.pix.pixelformat);
 
 	ret = ipu_ic_task_idma_init(priv->ic, channel,
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index 7afb7e367d76..e18f58f56dfb 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -114,6 +114,7 @@ struct csi_priv {
 	u32 frame_sequence; /* frame sequence counter */
 	bool last_eof;   /* waiting for last EOF at stream off */
 	bool nfb4eof;    /* NFB4EOF encountered during streaming */
+	bool interweave_swap; /* swap top/bottom lines when interweaving */
 	struct completion last_eof_comp;
 };
 
@@ -286,6 +287,9 @@ static void csi_vb2_buf_done(struct csi_priv *priv)
 	if (ipu_idmac_buffer_is_ready(priv->idmac_ch, priv->ipu_buf_num))
 		ipu_idmac_clear_buffer(priv->idmac_ch, priv->ipu_buf_num);
 
+	if (priv->interweave_swap)
+		phys += vdev->fmt.fmt.pix.bytesperline;
+
 	ipu_cpmem_set_buffer(priv->idmac_ch, priv->ipu_buf_num, phys);
 }
 
@@ -433,6 +437,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 	 */
 	interweave = V4L2_FIELD_IS_INTERLACED(image.pix.field) &&
 		V4L2_FIELD_IS_SEQUENTIAL(outfmt->field);
+	priv->interweave_swap = interweave &&
+		image.pix.field == V4L2_FIELD_INTERLACED_BT;
 
 	switch (image.pix.pixelformat) {
 	case V4L2_PIX_FMT_SBGGR8:
@@ -486,6 +492,12 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 	}
 
 	if (passthrough) {
+		if (priv->interweave_swap) {
+			/* start interweave scan at 1st top line (2nd line) */
+			image.phys0 += image.pix.bytesperline;
+			image.phys1 += image.pix.bytesperline;
+		}
+
 		ipu_cpmem_set_resolution(priv->idmac_ch,
 					 image.rect.width * passthrough_cycles,
 					 image.rect.height);
@@ -495,6 +507,11 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 		ipu_cpmem_set_format_passthrough(priv->idmac_ch,
 						 passthrough_bits);
 	} else {
+		if (priv->interweave_swap) {
+			/* start interweave scan at 1st top line (2nd line) */
+			image.rect.top = 1;
+		}
+
 		ret = ipu_cpmem_set_image(priv->idmac_ch, &image);
 		if (ret)
 			goto unsetup_vb2;
@@ -526,6 +543,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 
 	if (interweave)
 		ipu_cpmem_interlaced_scan(priv->idmac_ch,
+					  priv->interweave_swap ?
+					  -image.pix.bytesperline :
 					  image.pix.bytesperline,
 					  image.pix.pixelformat);
 
@@ -1338,16 +1357,27 @@ static void csi_try_field(struct csi_priv *priv,
 	switch (infmt->field) {
 	case V4L2_FIELD_SEQ_TB:
 	case V4L2_FIELD_SEQ_BT:
+		/*
+		 * If the user requests sequential at the source pad,
+		 * allow it (along with possibly inverting field order).
+		 * Otherwise passthrough the field type.
+		 */
+		if (!V4L2_FIELD_IS_SEQUENTIAL(sdformat->format.field))
+			sdformat->format.field = infmt->field;
+		break;
 	case V4L2_FIELD_ALTERNATE:
 		/*
-		 * If the sink is sequential or alternating fields,
-		 * allow only SEQ_TB at the source.
-		 *
 		 * This driver does not support alternate field mode, and
 		 * the CSI captures a whole frame, so the CSI never presents
-		 * alternate mode at its source pads.
+		 * alternate mode at its source pads. If user has not
+		 * already requested sequential, translate ALTERNATE at
+		 * sink pad to SEQ_TB or SEQ_BT at the source pad depending
+		 * on input height (assume NTSC BT order if 480 total active
+		 * frame lines, otherwise PAL TB order).
 		 */
-		sdformat->format.field = V4L2_FIELD_SEQ_TB;
+		if (!V4L2_FIELD_IS_SEQUENTIAL(sdformat->format.field))
+			sdformat->format.field = (infmt->height == 480 / 2) ?
+				V4L2_FIELD_SEQ_BT : V4L2_FIELD_SEQ_TB;
 		break;
 	default:
 		/* Passthrough for all other input field types */
-- 
2.17.1