media: s5p-jpeg: Add support for resolution change event

This patch adds support for resolution change event to notify clients so
they can prepare correct output buffer. When resolution change happened,
G_FMT for CAPTURE should return old resolution and format before CAPTURE
queues streamoff.

This event is used in the Chromium browser project by the V4L2 JPEG
Decode Accelerator (V4L2JDA) to allocate output buffer.

Signed-off-by: Henry-Ruey Hsu <henryhsu@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Acked-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/s5p-jpeg/jpeg-core.c

@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
+#include <media/v4l2-event.h>
 #include <media/v4l2-mem2mem.h>
 #include <media/v4l2-ioctl.h>
 #include <media/videobuf2-v4l2.h>
@@ -1633,8 +1634,6 @@ static int s5p_jpeg_s_fmt(struct s5p_jpeg_ctx *ct, struct v4l2_format *f)
 			FMT_TYPE_OUTPUT : FMT_TYPE_CAPTURE;
 
 	q_data->fmt = s5p_jpeg_find_format(ct, pix->pixelformat, f_type);
-	q_data->w = pix->width;
-	q_data->h = pix->height;
 	if (q_data->fmt->fourcc != V4L2_PIX_FMT_JPEG) {
 		/*
 		 * During encoding Exynos4x12 SoCs access wider memory area
@@ -1642,6 +1641,8 @@ static int s5p_jpeg_s_fmt(struct s5p_jpeg_ctx *ct, struct v4l2_format *f)
 		 * the JPEG_IMAGE_SIZE register. In order to avoid sysmmu
 		 * page fault calculate proper buffer size in such a case.
 		 */
+		q_data->w = pix->width;
+		q_data->h = pix->height;
 		if (ct->jpeg->variant->hw_ex4_compat &&
 		    f_type == FMT_TYPE_OUTPUT && ct->mode == S5P_JPEG_ENCODE)
 			q_data->size = exynos4_jpeg_get_output_buffer_size(ct,
@@ -1717,6 +1718,15 @@ static int s5p_jpeg_s_fmt_vid_out(struct file *file, void *priv,
 	return s5p_jpeg_s_fmt(fh_to_ctx(priv), f);
 }
 
+static int s5p_jpeg_subscribe_event(struct v4l2_fh *fh,
+				    const struct v4l2_event_subscription *sub)
+{
+	if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
+		return v4l2_src_change_event_subscribe(fh, sub);
+
+	return -EINVAL;
+}
+
 static int exynos3250_jpeg_try_downscale(struct s5p_jpeg_ctx *ctx,
 				   struct v4l2_rect *r)
 {
@@ -2042,6 +2052,9 @@ static const struct v4l2_ioctl_ops s5p_jpeg_ioctl_ops = {
 
 	.vidioc_g_selection		= s5p_jpeg_g_selection,
 	.vidioc_s_selection		= s5p_jpeg_s_selection,
+
+	.vidioc_subscribe_event		= s5p_jpeg_subscribe_event,
+	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
 };
 
 /*
@@ -2434,8 +2447,17 @@ static int s5p_jpeg_job_ready(void *priv)
 {
 	struct s5p_jpeg_ctx *ctx = priv;
 
-	if (ctx->mode == S5P_JPEG_DECODE)
+	if (ctx->mode == S5P_JPEG_DECODE) {
+		/*
+		 * We have only one input buffer and one output buffer. If there
+		 * is a resolution change event, no need to continue decoding.
+		 */
+		if (ctx->state == JPEGCTX_RESOLUTION_CHANGE)
+			return 0;
+
 		return ctx->hdr_parsed;
+	}
+
 	return 1;
 }
 
@@ -2514,6 +2536,30 @@ static int s5p_jpeg_buf_prepare(struct vb2_buffer *vb)
 	return 0;
 }
 
+static void s5p_jpeg_set_capture_queue_data(struct s5p_jpeg_ctx *ctx)
+{
+	struct s5p_jpeg_q_data *q_data = &ctx->cap_q;
+
+	q_data->w = ctx->out_q.w;
+	q_data->h = ctx->out_q.h;
+
+	/*
+	 * This call to jpeg_bound_align_image() takes care of width and
+	 * height values alignment when user space calls the QBUF of
+	 * OUTPUT buffer after the S_FMT of CAPTURE buffer.
+	 * Please note that on Exynos4x12 SoCs, resigning from executing
+	 * S_FMT on capture buffer for each JPEG image can result in a
+	 * hardware hangup if subsampling is lower than the one of input
+	 * JPEG.
+	 */
+	jpeg_bound_align_image(ctx, &q_data->w, S5P_JPEG_MIN_WIDTH,
+			       S5P_JPEG_MAX_WIDTH, q_data->fmt->h_align,
+			       &q_data->h, S5P_JPEG_MIN_HEIGHT,
+			       S5P_JPEG_MAX_HEIGHT, q_data->fmt->v_align);
+
+	q_data->size = q_data->w * q_data->h * q_data->fmt->depth >> 3;
+}
+
 static void s5p_jpeg_buf_queue(struct vb2_buffer *vb)
 {
 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
@@ -2521,7 +2567,18 @@ static void s5p_jpeg_buf_queue(struct vb2_buffer *vb)
 
 	if (ctx->mode == S5P_JPEG_DECODE &&
 	    vb->vb2_queue->type == V4L2_BUF_TYPE_VIDEO_OUTPUT) {
-		struct s5p_jpeg_q_data *q_data;
+		static const struct v4l2_event ev_src_ch = {
+			.type = V4L2_EVENT_SOURCE_CHANGE,
+			.u.src_change.changes = V4L2_EVENT_SRC_CH_RESOLUTION,
+		};
+		struct vb2_queue *dst_vq;
+		u32 ori_w;
+		u32 ori_h;
+
+		dst_vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx,
+					 V4L2_BUF_TYPE_VIDEO_CAPTURE);
+		ori_w = ctx->out_q.w;
+		ori_h = ctx->out_q.h;
 
 		ctx->hdr_parsed = s5p_jpeg_parse_hdr(&ctx->out_q,
 		     (unsigned long)vb2_plane_vaddr(vb, 0),
@@ -2532,28 +2589,18 @@ static void s5p_jpeg_buf_queue(struct vb2_buffer *vb)
 			return;
 		}
 
-		q_data = &ctx->cap_q;
-		q_data->w = ctx->out_q.w;
-		q_data->h = ctx->out_q.h;
-
 		/*
-		 * This call to jpeg_bound_align_image() takes care of width and
-		 * height values alignment when user space calls the QBUF of
-		 * OUTPUT buffer after the S_FMT of CAPTURE buffer.
-		 * Please note that on Exynos4x12 SoCs, resigning from executing
-		 * S_FMT on capture buffer for each JPEG image can result in a
-		 * hardware hangup if subsampling is lower than the one of input
-		 * JPEG.
+		 * If there is a resolution change event, only update capture
+		 * queue when it is not streaming. Otherwise, update it in
+		 * STREAMOFF. See s5p_jpeg_stop_streaming for detail.
 		 */
-		jpeg_bound_align_image(ctx,
-				       &q_data->w,
-				       S5P_JPEG_MIN_WIDTH, S5P_JPEG_MAX_WIDTH,
-				       q_data->fmt->h_align,
-				       &q_data->h,
-				       S5P_JPEG_MIN_HEIGHT, S5P_JPEG_MAX_HEIGHT,
-				       q_data->fmt->v_align);
-
-		q_data->size = q_data->w * q_data->h * q_data->fmt->depth >> 3;
+		if (ctx->out_q.w != ori_w || ctx->out_q.h != ori_h) {
+			v4l2_event_queue_fh(&ctx->fh, &ev_src_ch);
+			if (vb2_is_streaming(dst_vq))
+				ctx->state = JPEGCTX_RESOLUTION_CHANGE;
+			else
+				s5p_jpeg_set_capture_queue_data(ctx);
+		}
 	}
 
 	v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
@@ -2573,6 +2620,17 @@ static void s5p_jpeg_stop_streaming(struct vb2_queue *q)
 {
 	struct s5p_jpeg_ctx *ctx = vb2_get_drv_priv(q);
 
+	/*
+	 * STREAMOFF is an acknowledgment for resolution change event.
+	 * Before STREAMOFF, we still have to return the old resolution and
+	 * subsampling. Update capture queue when the stream is off.
+	 */
+	if (ctx->state == JPEGCTX_RESOLUTION_CHANGE &&
+	    q->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
+		s5p_jpeg_set_capture_queue_data(ctx);
+		ctx->state = JPEGCTX_RUNNING;
+	}
+
 	pm_runtime_put(ctx->jpeg->dev);
 }
 

drivers/media/platform/s5p-jpeg/jpeg-core.h

@@ -98,6 +98,11 @@ enum  exynos4_jpeg_img_quality_level {
 	QUALITY_LEVEL_4,	/* low */
 };
 
+enum s5p_jpeg_ctx_state {
+	JPEGCTX_RUNNING = 0,
+	JPEGCTX_RESOLUTION_CHANGE,
+};
+
 /**
  * struct s5p_jpeg - JPEG IP abstraction
  * @lock:		the mutex protecting this structure
@@ -220,6 +225,7 @@ struct s5p_jpeg_q_data {
  * @hdr_parsed:		set if header has been parsed during decompression
  * @crop_altered:	set if crop rectangle has been altered by the user space
  * @ctrl_handler:	controls handler
+ * @state:		state of the context
  */
 struct s5p_jpeg_ctx {
 	struct s5p_jpeg		*jpeg;
@@ -235,6 +241,7 @@ struct s5p_jpeg_ctx {
 	bool			hdr_parsed;
 	bool			crop_altered;
 	struct v4l2_ctrl_handler ctrl_handler;
+	enum s5p_jpeg_ctx_state	state;
 };
 
 /**