[libcamera-devel] [PATCH v3 4/4] ipa: ipu3: Replace ipa::ipu3::algorithms::Ipu3AwbCell
Jean-Michel Hautbois
jeanmichel.hautbois at ideasonboard.com
Tue Sep 7 08:44:13 CEST 2021
Hi JM,
On 06/09/2021 21:47, Jean-Michel Hautbois wrote:
> The intel-ipu3.h public interface from the kernel does not define how to
> parse the statistics for a cell. This had to be identified by a process
> of reverse engineering, and later identifying the structures from
> https://chromium.googlesource.com/chromiumos/platform/arc-camera/+/refs/heads/master/hal/intel/include/ia_imaging/awb_public.h
> leading to our custom definition of struct Ipu3AwbCell.
>
> To improve the kernel interface, a proposal has been made to the
> linux-kernel [0] to incorporate the memory layout for each cell into the
> intel-ipu3 header directly.
>
> [0]
> https://lore.kernel.org/linux-media/20210831185140.77400-1-jeanmichel.hautbois@ideasonboard.com/
>
> Update our local copy of the intel-ipu3.h to match the proposal and
> change the AGC and AWB algorithms to reference that structure directly,
> allowing us to remove the deprecated custom Ipu3AwbCell definition.
>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> ---
> include/linux/intel-ipu3.h | 38 +++++++++++++++++++++++++--------
> src/ipa/ipu3/algorithms/agc.cpp | 7 +++---
> src/ipa/ipu3/algorithms/awb.cpp | 11 +++++-----
> src/ipa/ipu3/algorithms/awb.h | 10 ---------
> 4 files changed, 38 insertions(+), 28 deletions(-)
>
> diff --git a/include/linux/intel-ipu3.h b/include/linux/intel-ipu3.h
> index ee0e6d0e..0633e04e 100644
> --- a/include/linux/intel-ipu3.h
> +++ b/include/linux/intel-ipu3.h
> @@ -59,20 +59,40 @@ struct ipu3_uapi_grid_config {
> __u16 y_end;
> } __attribute__((packed));
>
> +/**
> + * struct ipu3_uapi_awb_set_item - 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_set_item {
> + 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;
> +} __attribute__((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
>
>
> /**
> @@ -82,7 +102,7 @@ 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_set_item meta_data[IPU3_UAPI_AWB_MAX_BUFFER_SIZE]
> __attribute__((aligned(32)));
> } __attribute__((packed));
>
The idea is not bad, but you did not test it before sending, and forgot
one little thing: you need to align the kernel on it, because the sizes
defined here are not the same as before !
So, you could keep the old sizes defined (don't forget to remove the
IPU3_UAPI_AWB_MD_ITEM_SIZE multiplication though) or don't apply that
patch now...
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index 5ff50f4a..8740dcdf 100644
> --- a/src/ipa/ipu3/algorithms/agc.cpp
> +++ b/src/ipa/ipu3/algorithms/agc.cpp
> @@ -96,9 +96,10 @@ void Agc::processBrightness(const ipu3_uapi_stats_3a *stats,
> * We observed a bit shift which makes the value 160 to be 32 in the stats grid.
> * Use the one passed at init time.
> */
> - if (stats->awb_raw_buffer.meta_data[i + 4 + j * grid.width] == 0) {
> - uint8_t Gr = stats->awb_raw_buffer.meta_data[i + 0 + j * grid.width];
> - uint8_t Gb = stats->awb_raw_buffer.meta_data[i + 3 + j * grid.width];
> + const ipu3_uapi_awb_set_item *currentCell = &stats->awb_raw_buffer.meta_data[i + j * grid.width];
> + if (currentCell->sat_ratio == 0) {
> + uint8_t Gr = currentCell->Gr_avg;
> + uint8_t Gb = currentCell->Gb_avg;
> hist[(Gr + Gb) / 2]++;
> count++;
> }
> diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
> index bc0aa6fe..5d6fa4d4 100644
> --- a/src/ipa/ipu3/algorithms/awb.cpp
> +++ b/src/ipa/ipu3/algorithms/awb.cpp
> @@ -201,17 +201,16 @@ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats,
> uint32_t cellY = ((cellPosition / grid.width) / regionHeight) % kAwbStatsSizeY;
>
> uint32_t awbRegionPosition = cellY * kAwbStatsSizeX + cellX;
> - cellPosition *= 8;
>
> /* Cast the initial IPU3 structure to simplify the reading */
> - Ipu3AwbCell *currentCell = reinterpret_cast<Ipu3AwbCell *>(const_cast<uint8_t *>(&stats->awb_raw_buffer.meta_data[cellPosition]));
> - if (currentCell->satRatio == 0) {
> + const ipu3_uapi_awb_set_item *currentCell = &stats->awb_raw_buffer.meta_data[cellPosition];
> + if (currentCell->sat_ratio == 0) {
> /* The cell is not saturated, use the current cell */
> awbStats_[awbRegionPosition].counted++;
> - uint32_t greenValue = currentCell->greenRedAvg + currentCell->greenBlueAvg;
> + uint32_t greenValue = currentCell->Gr_avg + currentCell->Gb_avg;
> awbStats_[awbRegionPosition].sum.green += greenValue / 2;
> - awbStats_[awbRegionPosition].sum.red += currentCell->redAvg;
> - awbStats_[awbRegionPosition].sum.blue += currentCell->blueAvg;
> + awbStats_[awbRegionPosition].sum.red += currentCell->R_avg;
> + awbStats_[awbRegionPosition].sum.blue += currentCell->B_avg;
> }
> }
> }
> diff --git a/src/ipa/ipu3/algorithms/awb.h b/src/ipa/ipu3/algorithms/awb.h
> index 3385ebe7..17905ae8 100644
> --- a/src/ipa/ipu3/algorithms/awb.h
> +++ b/src/ipa/ipu3/algorithms/awb.h
> @@ -23,16 +23,6 @@ namespace ipa::ipu3::algorithms {
> static constexpr uint32_t kAwbStatsSizeX = 16;
> static constexpr uint32_t kAwbStatsSizeY = 12;
>
> -/* \todo Move the cell layout into intel-ipu3.h kernel header */
> -struct Ipu3AwbCell {
> - unsigned char greenRedAvg;
> - unsigned char redAvg;
> - unsigned char blueAvg;
> - unsigned char greenBlueAvg;
> - unsigned char satRatio;
> - unsigned char padding[3];
> -} __attribute__((packed));
> -
> struct Accumulator {
> unsigned int counted;
> struct {
>
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