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From:   Alexandre Courbot <acourbot@chromium.org>
To:     Tiffany Lin <tiffany.lin@mediatek.com>,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
        Yunfei Dong <yunfei.dong@mediatek.com>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org,
        Alexandre Courbot <acourbot@chromium.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>
Subject: [PATCH v5 05/14] media: mtk-vcodec: venc: support START and STOP commands
Date:   Wed, 19 May 2021 23:30:02 +0900
Message-Id: <20210519143011.1175546-6-acourbot@chromium.org>
In-Reply-To: <20210519143011.1175546-1-acourbot@chromium.org>
References: <20210519143011.1175546-1-acourbot@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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The V4L2 encoder specification requires encoders to support the
V4L2_ENC_CMD_START and V4L2_ENC_CMD_STOP commands. Add support for these
to the mtk-vcodec encoder by reusing the same flush buffer as used by
the decoder driver.

Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
[hsinyi: fix double-free issue if flush buffer was not dequeued by the
time streamoff is called]
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
 .../platform/mtk-vcodec/mtk_vcodec_drv.h      |   2 +
 .../platform/mtk-vcodec/mtk_vcodec_enc.c      | 135 +++++++++++++++++-
 .../platform/mtk-vcodec/mtk_vcodec_enc_drv.c  |   4 +
 3 files changed, 134 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_drv.h b/drivers/media/platform/mtk-vcodec/mtk_vcodec_drv.h
index c6fe61253f43..37a62c0f406f 100644
--- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_drv.h
+++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_drv.h
@@ -252,6 +252,7 @@ struct vdec_pic_info {
  * @last_decoded_picinfo: pic information get from latest decode
  * @empty_flush_buf: a fake size-0 capture buffer that indicates flush. Only
  *		     to be used with encoder and stateful decoder.
+ * @is_flushing: set to true if flushing is in progress.
  *
  * @colorspace: enum v4l2_colorspace; supplemental to pixelformat
  * @ycbcr_enc: enum v4l2_ycbcr_encoding, Y'CbCr encoding
@@ -290,6 +291,7 @@ struct mtk_vcodec_ctx {
 	struct work_struct encode_work;
 	struct vdec_pic_info last_decoded_picinfo;
 	struct v4l2_m2m_buffer empty_flush_buf;
+	bool is_flushing;
 
 	enum v4l2_colorspace colorspace;
 	enum v4l2_ycbcr_encoding ycbcr_enc;
diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c
index 4831052f475d..4701dea251ca 100644
--- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c
+++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc.c
@@ -659,6 +659,7 @@ static int vidioc_venc_dqbuf(struct file *file, void *priv,
 			     struct v4l2_buffer *buf)
 {
 	struct mtk_vcodec_ctx *ctx = fh_to_ctx(priv);
+	int ret;
 
 	if (ctx->state == MTK_STATE_ABORT) {
 		mtk_v4l2_err("[%d] Call on QBUF after unrecoverable error",
@@ -666,7 +667,77 @@ static int vidioc_venc_dqbuf(struct file *file, void *priv,
 		return -EIO;
 	}
 
-	return v4l2_m2m_dqbuf(file, ctx->m2m_ctx, buf);
+	ret = v4l2_m2m_dqbuf(file, ctx->m2m_ctx, buf);
+	if (ret)
+		return ret;
+
+	/*
+	 * Complete flush if the user dequeued the 0-payload LAST buffer.
+	 * We check the payload because a buffer with the LAST flag can also
+	 * be seen during resolution changes. If we happen to be flushing at
+	 * that time, the last buffer before the resolution changes could be
+	 * misinterpreted for the buffer generated by the flush and terminate
+	 * it earlier than we want.
+	 */
+	if (!V4L2_TYPE_IS_OUTPUT(buf->type) &&
+	    buf->flags & V4L2_BUF_FLAG_LAST &&
+	    buf->m.planes[0].bytesused == 0 &&
+	    ctx->is_flushing) {
+		/*
+		 * Last CAPTURE buffer is dequeued, we can allow another flush
+		 * to take place.
+		 */
+		ctx->is_flushing = false;
+	}
+
+	return 0;
+}
+
+static int vidioc_encoder_cmd(struct file *file, void *priv,
+			      struct v4l2_encoder_cmd *cmd)
+{
+	struct mtk_vcodec_ctx *ctx = fh_to_ctx(priv);
+	struct vb2_queue *src_vq, *dst_vq;
+	int ret;
+
+	ret = v4l2_m2m_ioctl_try_encoder_cmd(file, priv, cmd);
+	if (ret)
+		return ret;
+
+	/* Calling START or STOP is invalid if a flush is in progress */
+	if (ctx->is_flushing)
+		return -EBUSY;
+
+	mtk_v4l2_debug(1, "encoder cmd=%u", cmd->cmd);
+
+	dst_vq = v4l2_m2m_get_vq(ctx->m2m_ctx,
+				V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
+	switch (cmd->cmd) {
+	case V4L2_ENC_CMD_STOP:
+		src_vq = v4l2_m2m_get_vq(ctx->m2m_ctx,
+				V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
+		if (!vb2_is_streaming(src_vq)) {
+			mtk_v4l2_debug(1, "Output stream is off. No need to flush.");
+			return 0;
+		}
+		if (!vb2_is_streaming(dst_vq)) {
+			mtk_v4l2_debug(1, "Capture stream is off. No need to flush.");
+			return 0;
+		}
+		ctx->is_flushing = true;
+		v4l2_m2m_buf_queue(ctx->m2m_ctx, &ctx->empty_flush_buf.vb);
+		v4l2_m2m_try_schedule(ctx->m2m_ctx);
+		break;
+
+	case V4L2_ENC_CMD_START:
+		vb2_clear_last_buffer_dequeued(dst_vq);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 const struct v4l2_ioctl_ops mtk_venc_ioctl_ops = {
@@ -702,6 +773,9 @@ const struct v4l2_ioctl_ops mtk_venc_ioctl_ops = {
 
 	.vidioc_g_selection		= vidioc_venc_g_selection,
 	.vidioc_s_selection		= vidioc_venc_s_selection,
+
+	.vidioc_encoder_cmd		= vidioc_encoder_cmd,
+	.vidioc_try_encoder_cmd		= v4l2_m2m_ioctl_try_encoder_cmd,
 };
 
 static int vb2ops_venc_queue_setup(struct vb2_queue *vq,
@@ -869,9 +943,39 @@ static void vb2ops_venc_stop_streaming(struct vb2_queue *q)
 			dst_buf->vb2_buf.planes[0].bytesused = 0;
 			v4l2_m2m_buf_done(dst_buf, VB2_BUF_STATE_ERROR);
 		}
+		/* STREAMOFF on the CAPTURE queue completes any ongoing flush */
+		if (ctx->is_flushing) {
+			struct v4l2_m2m_buffer *b, *n;
+
+			mtk_v4l2_debug(1, "STREAMOFF called while flushing");
+			/*
+			 * STREAMOFF could be called before the flush buffer is
+			 * dequeued. Check whether empty flush buf is still in
+			 * queue before removing it.
+			 */
+			v4l2_m2m_for_each_src_buf_safe(ctx->m2m_ctx, b, n) {
+				if (b == &ctx->empty_flush_buf) {
+					v4l2_m2m_src_buf_remove_by_buf(
+							ctx->m2m_ctx, &b->vb);
+					break;
+				}
+			}
+			ctx->is_flushing = false;
+		}
 	} else {
-		while ((src_buf = v4l2_m2m_src_buf_remove(ctx->m2m_ctx)))
-			v4l2_m2m_buf_done(src_buf, VB2_BUF_STATE_ERROR);
+		while ((src_buf = v4l2_m2m_src_buf_remove(ctx->m2m_ctx))) {
+			if (src_buf != &ctx->empty_flush_buf.vb)
+				v4l2_m2m_buf_done(src_buf, VB2_BUF_STATE_ERROR);
+		}
+		if (ctx->is_flushing) {
+			/*
+			 * If we are in the middle of a flush, put the flush
+			 * buffer back into the queue so the next CAPTURE
+			 * buffer gets returned with the LAST flag set.
+			 */
+			v4l2_m2m_buf_queue(ctx->m2m_ctx,
+					   &ctx->empty_flush_buf.vb);
+		}
 	}
 
 	if ((q->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE &&
@@ -971,12 +1075,15 @@ static int mtk_venc_param_change(struct mtk_vcodec_ctx *ctx)
 {
 	struct venc_enc_param enc_prm;
 	struct vb2_v4l2_buffer *vb2_v4l2 = v4l2_m2m_next_src_buf(ctx->m2m_ctx);
-	struct mtk_video_enc_buf *mtk_buf =
-			container_of(vb2_v4l2, struct mtk_video_enc_buf,
-				     m2m_buf.vb);
-
+	struct mtk_video_enc_buf *mtk_buf;
 	int ret = 0;
 
+	/* Don't upcast the empty flush buffer */
+	if (vb2_v4l2 == &ctx->empty_flush_buf.vb)
+		return 0;
+
+	mtk_buf = container_of(vb2_v4l2, struct mtk_video_enc_buf, m2m_buf.vb);
+
 	memset(&enc_prm, 0, sizeof(enc_prm));
 	if (mtk_buf->param_change == MTK_ENCODE_PARAM_NONE)
 		return 0;
@@ -1062,6 +1169,20 @@ static void mtk_venc_worker(struct work_struct *work)
 	}
 
 	src_buf = v4l2_m2m_src_buf_remove(ctx->m2m_ctx);
+
+	/*
+	 * If we see the flush buffer, send an empty buffer with the LAST flag
+	 * to the client. is_flushing will be reset at the time the buffer
+	 * is dequeued.
+	 */
+	if (src_buf == &ctx->empty_flush_buf.vb) {
+		vb2_set_plane_payload(&dst_buf->vb2_buf, 0, 0);
+		dst_buf->flags |= V4L2_BUF_FLAG_LAST;
+		v4l2_m2m_buf_done(dst_buf, VB2_BUF_STATE_DONE);
+		v4l2_m2m_job_finish(ctx->dev->m2m_dev_enc, ctx->m2m_ctx);
+		return;
+	}
+
 	memset(&frm_buf, 0, sizeof(frm_buf));
 	for (i = 0; i < src_buf->vb2_buf.num_planes ; i++) {
 		frm_buf.fb_addr[i].dma_addr =
diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc_drv.c b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc_drv.c
index 7d7b8cfc2cc5..2dd6fef896df 100644
--- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc_drv.c
+++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_enc_drv.c
@@ -131,6 +131,7 @@ static int fops_vcodec_open(struct file *file)
 	struct mtk_vcodec_dev *dev = video_drvdata(file);
 	struct mtk_vcodec_ctx *ctx = NULL;
 	int ret = 0;
+	struct vb2_queue *src_vq;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
@@ -164,6 +165,9 @@ static int fops_vcodec_open(struct file *file)
 				ret);
 		goto err_m2m_ctx_init;
 	}
+	src_vq = v4l2_m2m_get_vq(ctx->m2m_ctx,
+				V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
+	ctx->empty_flush_buf.vb.vb2_buf.vb2_queue = src_vq;
 	mtk_vcodec_enc_set_default_params(ctx);
 
 	if (v4l2_fh_is_singular(&ctx->fh)) {
-- 
2.31.1.751.gd2f1c929bd-goog