Date:   Fri, 13 Dec 2019 10:06:03 +0100
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Nicolas Dufresne <nicolas@...fresne.ca>, mchehab@...nel.org,
        hans.verkuil@...co.com
Cc:     Maxime Jourdan <mjourdan@...libre.com>,
        linux-media@...r.kernel.org, linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] media: meson: vdec: add VP9 input support

On 05/12/2019 19:40, Nicolas Dufresne wrote:
> Le jeudi 05 décembre 2019 à 10:26 +0100, Neil Armstrong a écrit :
>> From: Maxime Jourdan <mjourdan@...libre.com>
>>
>> Amlogic VP9 decoder requires an additional 16-byte payload before every
>> frame header.
> 
> When I first saw this patch, I assumed data_offset was to be used (like
> for venus), but I think what I'm reading is that the bitstream is
> bounce into another buffer (ring buffer ?) and for this reason such an
> offset is not needed. Maybe worth referring to how the header is being
> added (e.g. while copying the data) ? 

The source buffer is updates in-situ, then given to the Parser, copied into
the parser ring buffer, then parses and copies the slice into the decoder "workspace".

I'll specify it the commit log.

Neil

> 
>>
>> Signed-off-by: Maxime Jourdan <mjourdan@...libre.com>
>> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
>> ---
>>  drivers/staging/media/meson/vdec/esparser.c | 142 +++++++++++++++++++-
>>  1 file changed, 138 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/staging/media/meson/vdec/esparser.c b/drivers/staging/media/meson/vdec/esparser.c
>> index adc5c1e81a4c..aeb68f6c732a 100644
>> --- a/drivers/staging/media/meson/vdec/esparser.c
>> +++ b/drivers/staging/media/meson/vdec/esparser.c
>> @@ -52,6 +52,7 @@
>>  #define PARSER_VIDEO_HOLE	0x90
>>  
>>  #define SEARCH_PATTERN_LEN	512
>> +#define VP9_HEADER_SIZE		16
>>  
>>  static DECLARE_WAIT_QUEUE_HEAD(wq);
>>  static int search_done;
>> @@ -74,14 +75,121 @@ static irqreturn_t esparser_isr(int irq, void *dev)
>>  	return IRQ_HANDLED;
>>  }
>>  
>> +/**
>> + * VP9 frame headers need to be appended by a 16-byte long
> 
> nit: Maybe the use of "appending" is not appropriate as the header is
> documented in the commit as being "before every frame header" ?
> 
>> + * Amlogic custom header
>> + */
>> +static int vp9_update_header(struct amvdec_core *core, struct vb2_buffer *buf)
>> +{
>> +	u8 *dp;
>> +	u8 marker;
>> +	int dsize;
>> +	int num_frames, cur_frame;
>> +	int cur_mag, mag, mag_ptr;
>> +	int frame_size[8], tot_frame_size[8];
>> +	int total_datasize = 0;
>> +	int new_frame_size;
>> +	unsigned char *old_header = NULL;
>> +
>> +	dp = (uint8_t *)vb2_plane_vaddr(buf, 0);
>> +	dsize = vb2_get_plane_payload(buf, 0);
>> +
>> +	if (dsize == vb2_plane_size(buf, 0)) {
>> +		dev_warn(core->dev, "%s: unable to update header\n", __func__);
>> +		return 0;
>> +	}
>> +
>> +	marker = dp[dsize - 1];
>> +	if ((marker & 0xe0) == 0xc0) {
>> +		num_frames = (marker & 0x7) + 1;
>> +		mag = ((marker >> 3) & 0x3) + 1;
>> +		mag_ptr = dsize - mag * num_frames - 2;
>> +		if (dp[mag_ptr] != marker)
>> +			return 0;
>> +
>> +		mag_ptr++;
>> +		for (cur_frame = 0; cur_frame < num_frames; cur_frame++) {
>> +			frame_size[cur_frame] = 0;
>> +			for (cur_mag = 0; cur_mag < mag; cur_mag++) {
>> +				frame_size[cur_frame] |=
>> +					(dp[mag_ptr] << (cur_mag * 8));
>> +				mag_ptr++;
>> +			}
>> +			if (cur_frame == 0)
>> +				tot_frame_size[cur_frame] =
>> +					frame_size[cur_frame];
>> +			else
>> +				tot_frame_size[cur_frame] =
>> +					tot_frame_size[cur_frame - 1] +
>> +					frame_size[cur_frame];
>> +			total_datasize += frame_size[cur_frame];
>> +		}
>> +	} else {
>> +		num_frames = 1;
>> +		frame_size[0] = dsize;
>> +		tot_frame_size[0] = dsize;
>> +		total_datasize = dsize;
>> +	}
>> +
>> +	new_frame_size = total_datasize + num_frames * VP9_HEADER_SIZE;
>> +
>> +	if (new_frame_size >= vb2_plane_size(buf, 0)) {
>> +		dev_warn(core->dev, "%s: unable to update header\n", __func__);
>> +		return 0;
>> +	}
>> +
>> +	for (cur_frame = num_frames - 1; cur_frame >= 0; cur_frame--) {
>> +		int framesize = frame_size[cur_frame];
>> +		int framesize_header = framesize + 4;
>> +		int oldframeoff = tot_frame_size[cur_frame] - framesize;
>> +		int outheaderoff =  oldframeoff + cur_frame * VP9_HEADER_SIZE;
>> +		u8 *fdata = dp + outheaderoff;
>> +		u8 *old_framedata = dp + oldframeoff;
>> +
>> +		memmove(fdata + VP9_HEADER_SIZE, old_framedata, framesize);
>> +
>> +		fdata[0] = (framesize_header >> 24) & 0xff;
>> +		fdata[1] = (framesize_header >> 16) & 0xff;
>> +		fdata[2] = (framesize_header >> 8) & 0xff;
>> +		fdata[3] = (framesize_header >> 0) & 0xff;
>> +		fdata[4] = ((framesize_header >> 24) & 0xff) ^ 0xff;
>> +		fdata[5] = ((framesize_header >> 16) & 0xff) ^ 0xff;
>> +		fdata[6] = ((framesize_header >> 8) & 0xff) ^ 0xff;
>> +		fdata[7] = ((framesize_header >> 0) & 0xff) ^ 0xff;
>> +		fdata[8] = 0;
>> +		fdata[9] = 0;
>> +		fdata[10] = 0;
>> +		fdata[11] = 1;
>> +		fdata[12] = 'A';
>> +		fdata[13] = 'M';
>> +		fdata[14] = 'L';
>> +		fdata[15] = 'V';
>> +
>> +		if (!old_header) {
>> +			/* nothing */
>> +		} else if (old_header > fdata + 16 + framesize) {
>> +			dev_dbg(core->dev, "%s: data has gaps, setting to 0\n",
>> +				__func__);
>> +			memset(fdata + 16 + framesize, 0,
>> +			       (old_header - fdata + 16 + framesize));
>> +		} else if (old_header < fdata + 16 + framesize) {
>> +			dev_err(core->dev, "%s: data overwritten\n", __func__);
>> +		}
>> +		old_header = fdata;
>> +	}
>> +
>> +	return new_frame_size;
>> +}
>> +
>>  /* Pad the packet to at least 4KiB bytes otherwise the VDEC unit won't trigger
>>   * ISRs.
>>   * Also append a start code 000001ff at the end to trigger
>>   * the ESPARSER interrupt.
>>   */
>> -static u32 esparser_pad_start_code(struct amvdec_core *core, struct vb2_buffer *vb)
>> +static u32 esparser_pad_start_code(struct amvdec_core *core,
>> +				   struct vb2_buffer *vb,
>> +				   u32 payload_size)
>>  {
>> -	u32 payload_size = vb2_get_plane_payload(vb, 0);
>>  	u32 pad_size = 0;
>>  	u8 *vaddr = vb2_plane_vaddr(vb, 0);
>>  
>> @@ -186,13 +294,27 @@ esparser_queue(struct amvdec_session *sess, struct vb2_v4l2_buffer *vbuf)
>>  	int ret;
>>  	struct vb2_buffer *vb = &vbuf->vb2_buf;
>>  	struct amvdec_core *core = sess->core;
>> +	struct amvdec_codec_ops *codec_ops = sess->fmt_out->codec_ops;
>>  	u32 payload_size = vb2_get_plane_payload(vb, 0);
>>  	dma_addr_t phy = vb2_dma_contig_plane_dma_addr(vb, 0);
>> +	u32 num_dst_bufs = 0;
>>  	u32 offset;
>>  	u32 pad_size;
>>  
>> -	if (esparser_vififo_get_free_space(sess) < payload_size)
>> +	if (sess->fmt_out->pixfmt == V4L2_PIX_FMT_VP9) {
>> +		if (codec_ops->num_pending_bufs)
>> +			num_dst_bufs = codec_ops->num_pending_bufs(sess);
>> +
>> +		num_dst_bufs += v4l2_m2m_num_dst_bufs_ready(sess->m2m_ctx);
>> +		if (sess->fmt_out->pixfmt == V4L2_PIX_FMT_VP9)
>> +			num_dst_bufs -= 2;
>> +
>> +		if (esparser_vififo_get_free_space(sess) < payload_size ||
>> +		    atomic_read(&sess->esparser_queued_bufs) >= num_dst_bufs)
>> +			return -EAGAIN;
>> +	} else if (esparser_vififo_get_free_space(sess) < payload_size) {
>>  		return -EAGAIN;
>> +	}
>>  
>>  	v4l2_m2m_src_buf_remove_by_buf(sess->m2m_ctx, vbuf);
>>  
>> @@ -206,7 +328,19 @@ esparser_queue(struct amvdec_session *sess, struct vb2_v4l2_buffer *vbuf)
>>  	vbuf->field = V4L2_FIELD_NONE;
>>  	vbuf->sequence = sess->sequence_out++;
>>  
>> -	pad_size = esparser_pad_start_code(core, vb);
>> +	if (sess->fmt_out->pixfmt == V4L2_PIX_FMT_VP9) {
>> +		payload_size = vp9_update_header(core, vb);
>> +
>> +		/* If unable to alter buffer to add headers */
>> +		if (payload_size == 0) {
>> +			amvdec_remove_ts(sess, vb->timestamp);
>> +			v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_ERROR);
>> +
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	pad_size = esparser_pad_start_code(core, vb, payload_size);
>>  	ret = esparser_write_data(core, phy, payload_size + pad_size);
>>  
>>  	if (ret <= 0) {




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