[PATCH v2 2/6] libcamera: mali-c55: Limit ISP input size

[Kieran Bingham]

Quoting Jacopo Mondi (2024-06-25 20:04:15)
> The Mali-C55 ISP has an input size limit of 640x480.
> 
> Filter out resolutions smaller than this when selecting the
> sensor format. While at it, rename 'maxYuvSize' to a more
> appropriate 'minSensorSize'.
> 
> Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> ---
>  src/libcamera/pipeline/mali-c55/mali-c55.cpp | 37 ++++++++++++--------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> 
> diff --git a/src/libcamera/pipeline/mali-c55/mali-c55.cpp b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> index 1c1fef2337f0..91f2ebd6fd26 100644
> --- a/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> +++ b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> @@ -79,6 +79,7 @@ const std::map<libcamera::PixelFormat, unsigned int> maliC55FmtToCode = {
>         { formats::SGRBG16, MEDIA_BUS_FMT_SGRBG16_1X16 },
>  };
>  
> +constexpr Size kMaliC55MinInputSize = { 640, 480 };
>  constexpr Size kMaliC55MinSize = { 128, 128 };
>  constexpr Size kMaliC55MaxSize = { 8192, 8192 };
>  constexpr unsigned int kMaliC55ISPInternalFormat = MEDIA_BUS_FMT_RGB121212_1X36;
> @@ -265,13 +266,16 @@ PixelFormat MaliC55CameraData::adjustRawFormat(const PixelFormat &rawFmt) const
>         return rawFmt;
>  }
>  
> -Size MaliC55CameraData::adjustRawSizes(const PixelFormat &rawFmt, const Size &rawSize) const
> +Size MaliC55CameraData::adjustRawSizes(const PixelFormat &rawFmt, const Size &size) const
>  {
>         /* Just make sure the format is supported. */
>         auto it = maliC55FmtToCode.find(rawFmt);
>         if (it == maliC55FmtToCode.end())
>                 return {};
>  
> +       /* Expand the RAW size to the minimum ISP input size. */
> +       Size rawSize = size.expandedTo(kMaliC55MinInputSize);
> +
>         /* Check if the size is natively supported. */
>         unsigned int rawCode = it->second;
>         const auto rawSizes = sizes(rawCode);
> @@ -282,14 +286,14 @@ Size MaliC55CameraData::adjustRawSizes(const PixelFormat &rawFmt, const Size &ra
>         /* Or adjust it to the closest supported size. */
>         uint16_t distance = std::numeric_limits<uint16_t>::max();
>         Size bestSize;
> -       for (const Size &size : rawSizes) {
> +       for (const Size &sz : rawSizes) {
>                 uint16_t dist = std::abs(static_cast<int>(rawSize.width) -
> -                                        static_cast<int>(size.width)) +
> +                                        static_cast<int>(sz.width)) +
>                                 std::abs(static_cast<int>(rawSize.height) -
> -                                        static_cast<int>(size.height));
> +                                        static_cast<int>(sz.height));
>                 if (dist < distance) {
>                         dist = distance;
> -                       bestSize = size;
> +                       bestSize = sz;
>                 }
>         }
>  
> @@ -376,8 +380,13 @@ CameraConfiguration::Status MaliC55CameraConfiguration::validate()
>                 frPipeAvailable = false;
>         }
>  
> -       /* Adjust processed streams. */
> -       Size maxYuvSize;
> +       /*
> +        * Adjust processed streams.
> +        *
> +        * Compute the minimum sensor size to be later used to select the
> +        * sensor configuration.
> +        */
> +       Size minSensorSize = kMaliC55MinInputSize;
>         for (StreamConfiguration &config : config_) {
>                 if (isFormatRaw(config.pixelFormat))
>                         continue;
> @@ -399,8 +408,8 @@ CameraConfiguration::Status MaliC55CameraConfiguration::validate()
>                         status = Adjusted;
>                 }
>  
> -               if (maxYuvSize < size)
> -                       maxYuvSize = size;
> +               if (minSensorSize < size)
> +                       minSensorSize = size;

This doesn't read well to me yet. Or maybe I'm tired, or it needs a comment.

If the miniumSensorSize is smaller than size we make the
miniumSensorSize bigger...

isn't a miniumSensorSize a constant? What is size here? The context
isn't very helpful as you've changed a different function above to also
have a parameter passed in now called size ... but I think that's a
'different' size to this one...

>  
>                 if (frPipeAvailable) {
>                         config.setStream(const_cast<Stream *>(&data_->frStream_));
> @@ -416,7 +425,7 @@ CameraConfiguration::Status MaliC55CameraConfiguration::validate()
>         if (rawConfig) {
>                 const auto it = maliC55FmtToCode.find(rawConfig->pixelFormat);
>                 sensorFormat_.code = it->second;
> -               sensorFormat_.size = rawConfig->size;
> +               sensorFormat_.size = rawConfig->size.expandedTo(minSensorSize);
>  
>                 return status;
>         }
> @@ -431,13 +440,13 @@ CameraConfiguration::Status MaliC55CameraConfiguration::validate()
>         Size bestSize;
>         for (const auto &size : sizes) {
>                 /* Skip sensor sizes that are smaller than the max YUV size. */

Should this comment change too ?

> -               if (maxYuvSize.width > size.width ||
> -                   maxYuvSize.height > size.height)
> +               if (minSensorSize.width > size.width ||
> +                   minSensorSize.height > size.height)
>                         continue;
>  
> -               uint16_t dist = std::abs(static_cast<int>(maxYuvSize.width) -
> +               uint16_t dist = std::abs(static_cast<int>(minSensorSize.width) -
>                                          static_cast<int>(size.width)) +
> -                               std::abs(static_cast<int>(maxYuvSize.height) -
> +                               std::abs(static_cast<int>(minSensorSize.height) -
>                                          static_cast<int>(size.height));
>                 if (dist < distance) {
>                         dist = distance;
> -- 
> 2.45.2
>