media: coda: add SPS fixup code for frame sizes that are not multiples of 16

The CODA7541 firmware does not set the SPS frame cropping fields to
properly describe coded h.264 streams with frame sizes that are not a
multiple of the macroblock size.
This adds RBSP parsing code and a SPS fixup routine to manually replace
the cropping information in the headers produced by the firmware with
the correct values.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
[hans.verkuil@cisco.com: added explanation of SPS RBSP to comment]
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/coda/coda-bit.c

@@ -1215,6 +1215,27 @@ static int coda_start_encoding(struct coda_ctx *ctx)
 		if (ret < 0)
 			goto out;
 
+		/*
+		 * If visible width or height are not aligned to macroblock
+		 * size, the crop_right and crop_bottom SPS fields must be set
+		 * to the difference between visible and coded size.  This is
+		 * only supported by CODA960 firmware. All others do not allow
+		 * writing frame cropping parameters, so we have to manually
+		 * fix up the SPS RBSP (Sequence Parameter Set Raw Byte
+		 * Sequence Payload) ourselves.
+		 */
+		if (ctx->dev->devtype->product != CODA_960 &&
+		    ((q_data_src->rect.width % 16) ||
+		     (q_data_src->rect.height % 16))) {
+			ret = coda_h264_sps_fixup(ctx, q_data_src->rect.width,
+						  q_data_src->rect.height,
+						  &ctx->vpu_header[0][0],
+						  &ctx->vpu_header_size[0],
+						  sizeof(ctx->vpu_header[0]));
+			if (ret < 0)
+				goto out;
+		}
+
 		/*
 		 * Get PPS in the first frame and copy it to an
 		 * intermediate buffer.

drivers/media/platform/coda/coda-h264.c

@@ -114,3 +114,319 @@ int coda_h264_level(int level_idc)
 	default: return -EINVAL;
 	}
 }
+
+struct rbsp {
+	char *buf;
+	int size;
+	int pos;
+};
+
+static inline int rbsp_read_bit(struct rbsp *rbsp)
+{
+	int shift = 7 - (rbsp->pos % 8);
+	int ofs = rbsp->pos++ / 8;
+
+	if (ofs >= rbsp->size)
+		return -EINVAL;
+
+	return (rbsp->buf[ofs] >> shift) & 1;
+}
+
+static inline int rbsp_write_bit(struct rbsp *rbsp, int bit)
+{
+	int shift = 7 - (rbsp->pos % 8);
+	int ofs = rbsp->pos++ / 8;
+
+	if (ofs >= rbsp->size)
+		return -EINVAL;
+
+	rbsp->buf[ofs] &= ~(1 << shift);
+	rbsp->buf[ofs] |= bit << shift;
+
+	return 0;
+}
+
+static inline int rbsp_read_bits(struct rbsp *rbsp, int num, int *val)
+{
+	int i, ret;
+	int tmp = 0;
+
+	if (num > 32)
+		return -EINVAL;
+
+	for (i = 0; i < num; i++) {
+		ret = rbsp_read_bit(rbsp);
+		if (ret < 0)
+			return ret;
+		tmp |= ret << (num - i - 1);
+	}
+
+	if (val)
+		*val = tmp;
+
+	return 0;
+}
+
+static int rbsp_write_bits(struct rbsp *rbsp, int num, int value)
+{
+	int ret;
+
+	while (num--) {
+		ret = rbsp_write_bit(rbsp, (value >> num) & 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int rbsp_read_uev(struct rbsp *rbsp, unsigned int *val)
+{
+	int leading_zero_bits = 0;
+	unsigned int tmp = 0;
+	int ret;
+
+	while ((ret = rbsp_read_bit(rbsp)) == 0)
+		leading_zero_bits++;
+	if (ret < 0)
+		return ret;
+
+	if (leading_zero_bits > 0) {
+		ret = rbsp_read_bits(rbsp, leading_zero_bits, &tmp);
+		if (ret)
+			return ret;
+	}
+
+	if (val)
+		*val = (1 << leading_zero_bits) - 1 + tmp;
+
+	return 0;
+}
+
+static int rbsp_write_uev(struct rbsp *rbsp, unsigned int value)
+{
+	int i;
+	int ret;
+	int tmp = value + 1;
+	int leading_zero_bits = fls(tmp) - 1;
+
+	for (i = 0; i < leading_zero_bits; i++) {
+		ret = rbsp_write_bit(rbsp, 0);
+		if (ret)
+			return ret;
+	}
+
+	return rbsp_write_bits(rbsp, leading_zero_bits + 1, tmp);
+}
+
+static int rbsp_read_sev(struct rbsp *rbsp, int *val)
+{
+	unsigned int tmp;
+	int ret;
+
+	ret = rbsp_read_uev(rbsp, &tmp);
+	if (ret)
+		return ret;
+
+	if (val) {
+		if (tmp & 1)
+			*val = (tmp + 1) / 2;
+		else
+			*val = -(tmp / 2);
+	}
+
+	return 0;
+}
+
+/**
+ * coda_h264_sps_fixup - fixes frame cropping values in h.264 SPS
+ * @ctx: encoder context
+ * @width: visible width
+ * @height: visible height
+ * @buf: buffer containing h.264 SPS RBSP, starting with NAL header
+ * @size: modified RBSP size return value
+ * @max_size: available size in buf
+ *
+ * Rewrites the frame cropping values in an h.264 SPS RBSP correctly for the
+ * given visible width and height.
+ */
+int coda_h264_sps_fixup(struct coda_ctx *ctx, int width, int height, char *buf,
+			int *size, int max_size)
+{
+	int profile_idc;
+	unsigned int pic_order_cnt_type;
+	int pic_width_in_mbs_minus1, pic_height_in_map_units_minus1;
+	int frame_mbs_only_flag, frame_cropping_flag;
+	int vui_parameters_present_flag;
+	unsigned int crop_right, crop_bottom;
+	struct rbsp sps;
+	int pos;
+	int ret;
+
+	if (*size < 8 || *size >= max_size)
+		return -EINVAL;
+
+	sps.buf = buf + 5; /* Skip NAL header */
+	sps.size = *size - 5;
+
+	profile_idc = sps.buf[0];
+	/* Skip constraint_set[0-5]_flag, reserved_zero_2bits */
+	/* Skip level_idc */
+	sps.pos = 24;
+
+	/* seq_parameter_set_id */
+	ret = rbsp_read_uev(&sps, NULL);
+	if (ret)
+		return ret;
+
+	if (profile_idc == 100 || profile_idc == 110 || profile_idc == 122 ||
+	    profile_idc == 244 || profile_idc == 44 || profile_idc == 83 ||
+	    profile_idc == 86 || profile_idc == 118 || profile_idc == 128 ||
+	    profile_idc == 138 || profile_idc == 139 || profile_idc == 134 ||
+	    profile_idc == 135) {
+		dev_err(ctx->fh.vdev->dev_parent,
+			"%s: Handling profile_idc %d not implemented\n",
+			__func__, profile_idc);
+		return -EINVAL;
+	}
+
+	/* log2_max_frame_num_minus4 */
+	ret = rbsp_read_uev(&sps, NULL);
+	if (ret)
+		return ret;
+
+	ret = rbsp_read_uev(&sps, &pic_order_cnt_type);
+	if (ret)
+		return ret;
+
+	if (pic_order_cnt_type == 0) {
+		/* log2_max_pic_order_cnt_lsb_minus4 */
+		ret = rbsp_read_uev(&sps, NULL);
+		if (ret)
+			return ret;
+	} else if (pic_order_cnt_type == 1) {
+		unsigned int i, num_ref_frames_in_pic_order_cnt_cycle;
+
+		/* delta_pic_order_always_zero_flag */
+		ret = rbsp_read_bit(&sps);
+		if (ret < 0)
+			return ret;
+		/* offset_for_non_ref_pic */
+		ret = rbsp_read_sev(&sps, NULL);
+		if (ret)
+			return ret;
+		/* offset_for_top_to_bottom_field */
+		ret = rbsp_read_sev(&sps, NULL);
+		if (ret)
+			return ret;
+
+		ret = rbsp_read_uev(&sps,
+				    &num_ref_frames_in_pic_order_cnt_cycle);
+		if (ret)
+			return ret;
+		for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) {
+			/* offset_for_ref_frame */
+			ret = rbsp_read_sev(&sps, NULL);
+			if (ret)
+				return ret;
+		}
+	}
+
+	/* max_num_ref_frames */
+	ret = rbsp_read_uev(&sps, NULL);
+	if (ret)
+		return ret;
+
+	/* gaps_in_frame_num_value_allowed_flag */
+	ret = rbsp_read_bit(&sps);
+	if (ret < 0)
+		return ret;
+	ret = rbsp_read_uev(&sps, &pic_width_in_mbs_minus1);
+	if (ret)
+		return ret;
+	ret = rbsp_read_uev(&sps, &pic_height_in_map_units_minus1);
+	if (ret)
+		return ret;
+	frame_mbs_only_flag = ret = rbsp_read_bit(&sps);
+	if (ret < 0)
+		return ret;
+	if (!frame_mbs_only_flag) {
+		/* mb_adaptive_frame_field_flag */
+		ret = rbsp_read_bit(&sps);
+		if (ret < 0)
+			return ret;
+	}
+	/* direct_8x8_inference_flag */
+	ret = rbsp_read_bit(&sps);
+	if (ret < 0)
+		return ret;
+
+	/* Mark position of the frame cropping flag */
+	pos = sps.pos;
+	frame_cropping_flag = ret = rbsp_read_bit(&sps);
+	if (ret < 0)
+		return ret;
+	if (frame_cropping_flag) {
+		unsigned int crop_left, crop_top;
+
+		ret = rbsp_read_uev(&sps, &crop_left);
+		if (ret)
+			return ret;
+		ret = rbsp_read_uev(&sps, &crop_right);
+		if (ret)
+			return ret;
+		ret = rbsp_read_uev(&sps, &crop_top);
+		if (ret)
+			return ret;
+		ret = rbsp_read_uev(&sps, &crop_bottom);
+		if (ret)
+			return ret;
+	}
+	vui_parameters_present_flag = ret = rbsp_read_bit(&sps);
+	if (ret < 0)
+		return ret;
+	if (vui_parameters_present_flag) {
+		dev_err(ctx->fh.vdev->dev_parent,
+			"%s: Handling vui_parameters not implemented\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	crop_right = round_up(width, 16) - width;
+	crop_bottom = round_up(height, 16) - height;
+	crop_right /= 2;
+	if (frame_mbs_only_flag)
+		crop_bottom /= 2;
+	else
+		crop_bottom /= 4;
+
+
+	sps.size = max_size - 5;
+	sps.pos = pos;
+	frame_cropping_flag = 1;
+	ret = rbsp_write_bit(&sps, frame_cropping_flag);
+	if (ret)
+		return ret;
+	ret = rbsp_write_uev(&sps, 0); /* crop_left */
+	if (ret)
+		return ret;
+	ret = rbsp_write_uev(&sps, crop_right);
+	if (ret)
+		return ret;
+	ret = rbsp_write_uev(&sps, 0); /* crop_top */
+	if (ret)
+		return ret;
+	ret = rbsp_write_uev(&sps, crop_bottom);
+	if (ret)
+		return ret;
+	ret = rbsp_write_bit(&sps, 0); /* vui_parameters_present_flag */
+	if (ret)
+		return ret;
+	ret = rbsp_write_bit(&sps, 1);
+	if (ret)
+		return ret;
+
+	*size = 5 + DIV_ROUND_UP(sps.pos, 8);
+
+	return 0;
+}

drivers/media/platform/coda/coda.h

@@ -305,6 +305,8 @@ int coda_h264_padding(int size, char *p);
 int coda_h264_profile(int profile_idc);
 int coda_h264_level(int level_idc);
 int coda_sps_parse_profile(struct coda_ctx *ctx, struct vb2_buffer *vb);
+int coda_h264_sps_fixup(struct coda_ctx *ctx, int width, int height, char *buf,
+			int *size, int max_size);
 
 bool coda_jpeg_check_buffer(struct coda_ctx *ctx, struct vb2_buffer *vb);
 int coda_jpeg_write_tables(struct coda_ctx *ctx);