Re: [PATCH v3 37/38] media: ti-vpe: cal: use frame desc to get vc and dt

Hi Tomi,

On Mon, Jun 07, 2021 at 03:07:42PM +0300, Tomi Valkeinen wrote:

On 04/06/2021 17:25, Laurent Pinchart wrote:

quoted

On Mon, May 24, 2021 at 02:09:08PM +0300, Tomi Valkeinen wrote:

quoted

Use get_frame_desc() to get the frame desc from the connected source,
and use the provided virtual channel and datatype instead of hardcoded
ones.

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 and any datatype.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
  drivers/media/platform/ti-vpe/cal-camerarx.c | 26 +++++++++++
  drivers/media/platform/ti-vpe/cal.c          | 49 +++++++++++++++++++-
  drivers/media/platform/ti-vpe/cal.h          |  3 ++
  3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
index e3a4c20be1e6..cb6a37f47432 100644
--- a/drivers/media/platform/ti-vpe/cal-camerarx.c
+++ b/drivers/media/platform/ti-vpe/cal-camerarx.c

@@ -583,6 +583,32 @@ static int cal_camerarx_parse_dt(struct cal_camerarx *phy)
  	return ret;
  }
  
+int cal_camerarx_get_remote_frame_desc(struct cal_camerarx *phy,
+				       struct v4l2_mbus_frame_desc *fd)

Maybe s/fd/desc/ to avoid the confusion with file descriptor ?

Good point.

quoted

quoted

+{
+	struct media_pad *pad;
+	int ret;
+
+	if (!phy->source)
+		return -ENODEV;

Would EPIPE (here and below) be a better error ? It will be returned to
userspace from VIDIOC_STREAMON(), which already uses EPIPE to indicate
that the links are not correctly set up.

Sound fine to me.

quoted

quoted

+
+	pad = media_entity_remote_pad(&phy->pads[CAL_CAMERARX_PAD_SINK]);
+	if (!pad)
+		return -ENODEV;
+
+	ret = v4l2_subdev_call(phy->source, pad, get_frame_desc, pad->index,
+			       fd);
+	if (ret)
+		return ret;
+
+	if (fd->type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2) {
+		dev_err(phy->cal->dev, "Frame desc do not describe CSI-2 link");

s/do not/does not/ and maybe s/desc/descriptor/

Yep.

quoted

quoted

+		return -EINVAL;
+	}
+
+	return 0;
+}
+
  /* ------------------------------------------------------------------
   *	V4L2 Subdev Operations
   * ------------------------------------------------------------------

diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
index fcc81024ae18..7975bb449acd 100644
--- a/drivers/media/platform/ti-vpe/cal.c
+++ b/drivers/media/platform/ti-vpe/cal.c

@@ -469,10 +469,56 @@ static bool cal_ctx_wr_dma_stopped(struct cal_ctx *ctx)
  	return stopped;
  }
  
+static int
+cal_get_remote_frame_desc_entry(struct cal_camerarx *phy, u32 stream,
+				struct v4l2_mbus_frame_desc_entry *entry)
+{
+	struct v4l2_mbus_frame_desc fd;
+	unsigned int i;
+	int ret;
+
+	ret = cal_camerarx_get_remote_frame_desc(phy, &fd);
+	if (ret) {
+		if (ret != -ENOIOCTLCMD)
+			dev_err(phy->cal->dev,
+				"Failed to get remote frame desc: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < fd.num_entries; i++) {
+		if (stream == fd.entry[i].stream) {
+			*entry = fd.entry[i];
+			return 0;
+		}
+	}
+

A dev_dbg() would be good here, in which case you could drop the
ctx_err() in cal_ctx_prepare() as all error paths will print a message.

Hmm, yes, or maybe the other way around: remove the dev_err above, and 
let the cal_ctx_prepare handle the printing (as it already does).

But perhaps it's better to add a dev_err (did you mean dev_err, when you 
said dev_dbg?) above before the return -ENODEV to make it clear if the 
error is coming from get_remote_frame_desc or from trying to find the 
stream.

I usually prefer debug messages for anything that can be triggered by
userspace and isn't a kernel error. Not sure which one it is here :-)

quoted

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

quoted

+	return -ENODEV;
+}
+
  int cal_ctx_prepare(struct cal_ctx *ctx)
  {
+	struct v4l2_mbus_frame_desc_entry entry;
  	int ret;
  
+	ret = cal_get_remote_frame_desc_entry(ctx->phy, ctx->stream, &entry);
+
+	if (ret == -ENOIOCTLCMD) {
+		ctx->vc = 0;
+		ctx->datatype = CAL_CSI2_CTX_DT_ANY;
+	} else if (!ret) {
+		ctx_dbg(2, ctx, "Framedesc: stream %u, len %u, vc %u, dt %#x\n",
+		       entry.stream,
+		       entry.length,
+		       entry.bus.csi2.vc,
+		       entry.bus.csi2.dt);

You can group multiple variables on the same line.

Yep.

-- 
Regards,

Laurent Pinchart