[PATCH v3 10/10] media: aspeed: add a workaround to fix a silicon bug

[Hans Verkuil]

Eddie: ping!

Regards,

	Hans

On 6/6/19 2:53 AM, Jae Hyun Yoo wrote:
> Hi Eddie,
> 
> All patches in this series were queued to linux/media tree except this
> one. Can you please review this patch?
> 
> Thanks,
> Jae
> 
> On 5/31/2019 3:15 PM, Jae Hyun Yoo wrote:
>> AST2500 silicon revision A1 and A2 have a silicon bug which causes
>> extremly long capturing time on specific resolutions (1680 width).
>> To fix the bug, this commit adjusts the capturing window register
>> setting to 1728 if detected width is 1680. The compression window
>> register setting will be kept as the original width so output
>> result will be the same.
>>
>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo at linux.intel.com>
>> ---
>> v2 -> v3:
>>   Added more detail comments why the value 1728 is picked.
>>
>> v1 -> v2:
>>   New.
>>
>>   drivers/media/platform/aspeed-video.c | 28 ++++++++++++++++++++-------
>>   1 file changed, 21 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
>> index ba093096a5a7..f899ac3b4a61 100644
>> --- a/drivers/media/platform/aspeed-video.c
>> +++ b/drivers/media/platform/aspeed-video.c
>> @@ -824,8 +824,29 @@ static void aspeed_video_set_resolution(struct aspeed_video *video)
>>   	struct v4l2_bt_timings *act = &video->active_timings;
>>   	unsigned int size = act->width * act->height;
>>   
>> +	/* Set capture/compression frame sizes */
>>   	aspeed_video_calc_compressed_size(video, size);
>>   
>> +	if (video->active_timings.width == 1680) {
>> +		/*
>> +		 * This is a workaround to fix a silicon bug on A1 and A2
>> +		 * revisions. Since it doesn't break capturing operation of
>> +		 * other revisions, use it for all revisions without checking
>> +		 * the revision ID. It picked 1728 which is a very next
>> +		 * 64-pixels aligned value to 1680 to minimize memory bandwidth
>> +		 * and to get better access speed from video engine.
>> +		 */
>> +		aspeed_video_write(video, VE_CAP_WINDOW,
>> +				   1728 << 16 | act->height);
>> +		size += (1728 - 1680) * video->active_timings.height;
>> +	} else {
>> +		aspeed_video_write(video, VE_CAP_WINDOW,
>> +				   act->width << 16 | act->height);
>> +	}
>> +	aspeed_video_write(video, VE_COMP_WINDOW,
>> +			   act->width << 16 | act->height);
>> +	aspeed_video_write(video, VE_SRC_SCANLINE_OFFSET, act->width * 4);
>> +
>>   	/* Don't use direct mode below 1024 x 768 (irqs don't fire) */
>>   	if (size < DIRECT_FETCH_THRESHOLD) {
>>   		aspeed_video_write(video, VE_TGS_0,
>> @@ -842,13 +863,6 @@ static void aspeed_video_set_resolution(struct aspeed_video *video)
>>   		aspeed_video_update(video, VE_CTRL, 0, VE_CTRL_DIRECT_FETCH);
>>   	}
>>   
>> -	/* Set capture/compression frame sizes */
>> -	aspeed_video_write(video, VE_CAP_WINDOW,
>> -			   act->width << 16 | act->height);
>> -	aspeed_video_write(video, VE_COMP_WINDOW,
>> -			   act->width << 16 | act->height);
>> -	aspeed_video_write(video, VE_SRC_SCANLINE_OFFSET, act->width * 4);
>> -
>>   	size *= 4;
>>   
>>   	if (size != video->srcs[0].size) {
>>