[libcamera-devel] [PATCH] ipa: ipu3: Replace ipa::ipu3::algorithms::Ipu3AwbCell
Kieran Bingham
kieran.bingham at ideasonboard.com
Thu Sep 2 17:46:49 CEST 2021
On 02/09/2021 14:29, Jean-Michel Hautbois wrote:
> This patch was proposed in:
> https://lore.kernel.org/linux-media/20210831185140.77400-1-jeanmichel.hautbois@ideasonboard.com/
That's not accurate, and it dives off to an external reference without
explaining why. /This/ patch is not proposed for linux-media.
Try to introduce your patches, and think about your commit message in
distinct sections such as:
- Describe the issue
- Describe any context
- Describe solution
- the issue
"""
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.
"""
- context
"""
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/
"""
- solution / What this patch does
"""
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.
"""
The only issue is that the proposal to linux-media has not yet been
reviewed or approved/integrated, so until then this patch would cause us
to diverge from the kernel version of the header and would require
special attention.
That may not be an issue in this case, as we can track the progress
upstream - but normally we would expect to keep our linux headers
matching the kernel unmodified.
> It introduces the AWB metadata layout as a structure in the kernel
> header, to make it clear for userspace applications. As intel-ipu3.h now
> has a defined AWB layout, use that one instead of the
> ipa::ipu3::algorithms::Ipu3AwbCell.
>
> 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 | 10 ++++-----
> src/ipa/ipu3/algorithms/awb.h | 10 ---------
> 4 files changed, 38 insertions(+), 27 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));
>
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index 5ff50f4a..36f648be 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 + 4 + 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 ea567f96..db0a22d3 100644
> --- a/src/ipa/ipu3/algorithms/awb.cpp
> +++ b/src/ipa/ipu3/algorithms/awb.cpp
> @@ -207,14 +207,14 @@ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats,
> 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 23f3e872..a9320b4c 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;
> unsigned int total;
>
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