android13/hardware/rockchip/libgralloc/bifrost

Mali GPUs Gralloc Module User Guide

Build time configuration

The project is designed to support multiple Android releases and HAL interface versions. Consequently, a configuration step is required before invoking make to build the project. The standard workflow is to setup the AOSP build environment as usual and run configure with no arguments. The script will determine which build files to enable based on the environment.

source build/envsetup.sh
lunch <target>
vendor/arm/gralloc/configure

Runtime configuration

This Gralloc implementation chooses an optimal image format based on the system hardware capabilities. These capabilities are expressed in XML and read at runtime. All configuration files with the .xml file extension are iterated and read from the /vendor/etc/gralloc directory.

XML file format

Version 0.1

Not supported by this version of Gralloc.

Version 0.2

See interfaces/capabilities/capabilities_type.xsd for the XML schema definition.

Changelog

Version 0.2

• Changed XML schema to support specifying multiple IPs in a single XML file
• The IPs no longer are described based on the filename but has been moved inside the XML schema.

Description

The <capabilities> element is the root of the XML document. It must have a version attribute with the value 0.2 and a valid <ip_capabilities> attribute/s.

The <ip_capabilities> attribute describes the a set of capabilities for an IP. The <ip_capabilities> has an ip field which specifies the actual IP for which the capabilities are described. The following values can be specified for the ip field:

IP
GPU
DPU
DPU_AEU
VPU
CAM

It is important to note that these values are case sensitive and must be in all uppercase characters.

The table below lists the way Gralloc will interpret the relevant usages for specific ip attributes used.

IP	Relevant usages	Interpretation
GPU	GPU_RENDER_TARGET	Write
	GPU_TEXTURE	Read
	GPU_DATA_BUFFER	Read
DPU	COMPOSER_CLIENT_TARGET	Write
	COMPOSER_OVERLAY	Read
VPU	VIDEO_ENCODER	Write
	VIDEO_DECODER	Read
CAM	CAMERA_OUTPUT	Write
	CAMERA_INPUT	Read

Within the <ip_capabilities> element are zero or more <feature> elements. These elements specify what Gralloc features/formats are supported by the IP block. Each <feature> element must have a name attribute. Listed below are all the accepted feature names and their descriptions. In addition to the name attribute, a permission attribute specifies whether the feature is available for read or write access.

Permissions

Permission	Description
RW	Read and write possible
RO	Read only
WO	Write only
NO	No capability (default)

Additional uncompressed formats

Feature	Description
FORMAT_R10G10B10A2	RGBA_1010102 format
FORMAT_R16G16B16A16_FLOAT	RGBA_FP16 format
YUV_BL_8	8-bit 16x16 block-linear formats (not CPU accessible)
YUV_BL_10	10-bit 16x16 block-linear formats (not CPU accessible)

Arm Framebuffer Compression ('AFBC') features

Feature	Description
AFBC_16X16	16x16 'basic' block size (required for all AFBC modes)
AFBC_32X8	32x8 'wide' block size
AFBC_64X4	64x4 'extra-wide' block size (multi-plane)
AFBC_BLOCK_SPLIT	Block split feature (applicable to 16x16 and 32x8 modes)
AFBC_TILED_HEADERS	Tiled header layout
AFBC_DOUBLE_BODY	Double body layout (useful for single buffer surfaces)
AFBC_WRITE_NON_SPARSE	Producer requires sparse layout
AFBC_YUV	Permits AFBC with YUV formats
AFBC_FORMAT_R16G16B16A16_FLOAT	Permits AFBC with RGBA_FP16 format

Arm Fixed Rate Compression ('AFRC') features

Feature	Description
AFRC_ROT_LAYOUT	Inline rotation capable layout
AFRC_SCAN_LAYOUT	Scanline optimized layout

Example

/vendor/etc/gralloc/capabilities.xml

<capabilities version="0.2">
  <ip_capabilities ip="GPU">
    <feature name="FORMAT_R10G10B10A2" permission="RW" />
    <feature name="FORMAT_R16G16B16A16_FLOAT" permission="RW" />
    <feature name="AFBC_16X16" permission="RW" />
    <feature name="AFBC_32X8" permission="RW" />
    <feature name="AFBC_YUV" permission="RW" />
    <feature name="AFBC_BLOCK_SPLIT" permission="RW" />
    <feature name="YUV_BL_8" permission="RO" />
  </ip_capabilities>

  <ip_capabilities ip="DPU">
    <feature name="FORMAT_R10G10B10A2" permission="RO" />
    <feature name="FORMAT_R16G16B16A16_FLOAT" permission="RO" />
    <feature name="AFBC_16X16" permission="RO" />
    <feature name="AFBC_YUV" permission="RO" />
    <feature name="YUV_BL_8" permission="RO" />
  </ip_capabilities>
</capabilities>

Notes

• CPU capabilities are fixed and not customizable.
• All features are opt-in; they are assumed to be unsupported if unspecified in the configuration.
• Having multiple specifications of capabilities (i.e. multiple <ip_capabilities> nodes with the same ip attribute) in the configuration files should be considered invalid usage and will cause undefined behavior.