Re: [RFC PATCH] media: staging: ipu3-imgu: add the AWB memory layout

[Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>]

Hi Bingbu, thanks for your answer !

On 09/09/2021 04:19, Bingbu Cao wrote:
> Jean-Michel,
> 
> Thanks for your patch.
> 
> On 9/8/21 4:17 PM, Laurent Pinchart wrote:
>> Hello,
>>
>> (CC'ing Tomasz)
>>
>> Gentle ping.
>>
>> On Wed, Sep 01, 2021 at 12:34:00AM +0300, Laurent Pinchart wrote:
>>> On Tue, Aug 31, 2021 at 08:51:40PM +0200, Jean-Michel Hautbois wrote:
>>>> While parsing the RAW AWB metadata, the AWB layout was missing to fully
>>>> understand which byte corresponds to which feature. Make the field names
>>>> and usage explicit, as it is used by the userspace applications.
>>>>
>>>> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
>>>> ---
>>>> This structure layout is defined in CrOs:
>>>> https://chromium.googlesource.com/chromiumos/platform/arc-camera/+/refs/heads/master/hal/intel/include/ia_imaging/awb_public.h
>>>>
>>>> There are a few things not really understood right now:
>>>> - Is sat_ratio a full scale ratio (I can't get more than some values out
>>>>   of it, is it a ratio of 25%, 50%, 75%, 100% ?)
>>>> - What are the real minimum and maximum values for the grid size ? From
>>>>   CrOs it appears to be [16, 80] for width and [16, 60] for height while
>>>>   in this file it seems to be [16, 160] for width and not really defined
>>>>   for height AFAICT ?
>>>> - Same for the block_width_log2 and block_height_log2 which are [3, 7]
>>>>   in this file and [3, 6] in the awb_public.h header ?

Do you have any clue for those questions please :-) ?

>>>>
>>>>  .../media/ipu3/include/uapi/intel-ipu3.h      | 38 ++++++++++++++-----
>>>>  1 file changed, 29 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h
>>>> index fa3d6ee5adf2..83191aff2ddd 100644
>>>> --- a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h
>>>> +++ b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h
>>>> @@ -61,20 +61,40 @@ struct ipu3_uapi_grid_config {
>>>>  	__u16 y_end;
>>>>  } __packed;
>>>>  
>>>> +/**
>>>> + * struct ipu3_uapi_awb_raw_buffer - Memory layout for each cell in AWB
>>>> + *
>>>> + * @Gr_avg:	Green average for red lines in the cell.
>>>> + * @R_avg:	Red average in the cell.
>>>> + * @B_avg:	Blue average in the cell.
>>>> + * @Gb_avg:	Green average for blue lines in the cell.
>>>> + * @sat_ratio:  Saturation ratio in the cell.
>>>> + * @padding0:   Unused byte for padding.
>>>> + * @padding1:   Unused byte for padding.
>>>> + * @padding2:   Unused byte for padding.
>>>> + */
>>>> +struct ipu3_uapi_awb_raw_buffer {
>>>> +    unsigned char Gr_avg;
>>>> +    unsigned char R_avg;
>>>> +    unsigned char B_avg;
>>>> +    unsigned char Gb_avg;
>>>> +    unsigned char sat_ratio;
>>>> +    unsigned char padding0;
>>>> +    unsigned char padding1;
>>>> +    unsigned char padding2;
> 
> It is fine for me to define and exposure the awb memory layout in uAPI.
> 
> nit: use __u8 here?

Sure !

> 
>>>> +} __packed;
>>>> +
>>>>  /*
>>>>   * The grid based data is divided into "slices" called set, each slice of setX
>>>>   * refers to ipu3_uapi_grid_config width * height_per_slice.
>>>>   */
>>>>  #define IPU3_UAPI_AWB_MAX_SETS				60
>>>> -/* Based on grid size 80 * 60 and cell size 16 x 16 */
>>>> -#define IPU3_UAPI_AWB_SET_SIZE				1280
>>>> -#define IPU3_UAPI_AWB_MD_ITEM_SIZE			8
>>>> -#define IPU3_UAPI_AWB_SPARE_FOR_BUBBLES \
>>>> -	(IPU3_UAPI_MAX_BUBBLE_SIZE * IPU3_UAPI_MAX_STRIPES * \
>>>> -	 IPU3_UAPI_AWB_MD_ITEM_SIZE)
>>>> +#define AWB_PUBLIC_NUM_OF_ITEMS_IN_SET			160
>>>> +/* Based on max grid height + Spare for bubbles */
>>>> +#define AWB_PUBLIC_NUM_OF_SETS_IN_BUFFER IPU3_UAPI_AWB_MAX_SETS + \
>>>> +	(IPU3_UAPI_MAX_BUBBLE_SIZE * IPU3_UAPI_MAX_STRIPES)
>>>>  #define IPU3_UAPI_AWB_MAX_BUFFER_SIZE \
>>>> -	(IPU3_UAPI_AWB_MAX_SETS * \
>>>> -	 (IPU3_UAPI_AWB_SET_SIZE + IPU3_UAPI_AWB_SPARE_FOR_BUBBLES))
>>>> +        AWB_PUBLIC_NUM_OF_SETS_IN_BUFFER * AWB_PUBLIC_NUM_OF_ITEMS_IN_SET
> 
> It's better to update the name of 'IPU3_UAPI_AWB_MAX_BUFFER_SIZE' to align current
> definition.
> 
>>>>  
>>>>  /**
>>>>   * struct ipu3_uapi_awb_raw_buffer - AWB raw buffer
>>>> @@ -83,7 +103,7 @@ struct ipu3_uapi_grid_config {
>>>>   *		the average values for each color channel.
>>>>   */
>>>>  struct ipu3_uapi_awb_raw_buffer {
>>>> -	__u8 meta_data[IPU3_UAPI_AWB_MAX_BUFFER_SIZE]
>>>> +	struct ipu3_uapi_awb_raw_buffer meta_data[IPU3_UAPI_AWB_MAX_BUFFER_SIZE]
>>>>  		__attribute__((aligned(32)));
>>>>  } __packed;
>>>>  
>>
>