sdk/fidl/fuchsia.images2/format_modifier.fidl

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.images2;

/// The upper 8 bits are a vendor code. The lower 56 bits are vendor-defined.
///
/// The defined `PixelFormatModifier` values are specific, complete, and valid
/// values (except for `INVALID` and `DO_NOT_CARE` which have their own
/// meanings).
///
/// Some other valid or potentially-valid `pixel_format_modifier` values are not
/// defined as a `PixelFormatModifier` value, typically because the value isn't
/// used in practice (or potentially is newly used but not yet defined in
/// `PixelFormatModifier`). It is permitted to specify such a value as a
/// `PixelFormatModifier` value in a `pixel_format_modifier` field, despite the
/// lack of corresponding defined `PixelFormatModifier` value. If such a value
/// is used outside test code, please consider adding it as a defined value in
/// `PixelFormatModifier`. All such values must conform to the upper 8 bits
/// vendor code (don't define/use values outside the/an appropriate vendor
/// code).
///
/// The separately-defined `FORMAT_MODIFIER_*` uint64 values are vendor-specific
/// bit field values, not complete valid values on their own. These uint64
/// values can be used to help create or interpret a `PixelFormatModifier` value
/// in terms of vendor-specific bitfields.
///
/// When the `pixel_format_modifier` is set to a supported value (excluding
/// `DO_NOT_CARE`, `INVALID`, `LINEAR`), the arrangement of pixel data otherwise
/// specified by the `pixel_format` field is "modified", typically to allow for
/// some combination of tiling, compression (typically lossless, typically for
/// memory bandwidth reduction not framebuffer size reduction), transaction
/// elimination, dirt tracking, but typically not modifying the bit depth of the
/// `pixel_format`. In some cases there's a per-image or per-tile header
/// involved, or similar. The `pixel_format` field often still needs to be set
/// to a valid supported value that works in combination with the
/// `pixel_format_modifier`, and that `pixel_format` value can also contribute
/// to the overall meaning of the `ImageFormat`. In other words, the "modifier"
/// part of the name is more accurate than "override" would be.
type PixelFormatModifier = flexible enum : uint64 {
    DO_NOT_CARE = 0x00FFFFFFFFFFFFFE;

    INVALID = 0x00FFFFFFFFFFFFFF;

    LINEAR = 0x0000000000000000;

    //
    // Fill in (compatible) values below as needed.
    //

    // Intel format modifier values

    INTEL_I915_X_TILED = 0x0100000000000001;
    INTEL_I915_Y_TILED = 0x0100000000000002;
    INTEL_I915_YF_TILED = 0x0100000000000003;

    INTEL_I915_Y_TILED_CCS = 0x0100000001000002;
    INTEL_I915_YF_TILED_CCS = 0x0100000001000003;

    // AMD format modifier values

    // NVIDIA format modifier values

    // SAMSUNG format modifier values

    // QCOM format modifier values

    // VIVANTE format modifier values

    // BROADCOM format modifier values

    // ARM format modifier values

    // Not all values are equally useful, so we only have format modifiers for some particularly interesting ones.

    // To make the variants with bits set more consistent 0x0800000000000000 is reserved for linear.
    ARM_AFBC_16X16 = 0x0800000000000001;
    ARM_AFBC_32X8 = 0x0800000000000002;
    // Variations with transaction elimination support 0x1000 should be set for these formats.
    ARM_LINEAR_TE = 0x0800000000001000;
    ARM_AFBC_16X16_TE = 0x0800000000001001;
    ARM_AFBC_32X8_TE = 0x0800000000001002;

    ARM_AFBC_16X16_YUV_TILED_HEADER = 0x0800000000002011;

    ARM_AFBC_16X16_SPLIT_BLOCK_SPARSE_YUV = 0x0800000000000071;
    ARM_AFBC_16X16_SPLIT_BLOCK_SPARSE_YUV_TE = 0x0800000000001071;

    ARM_AFBC_16X16_SPLIT_BLOCK_SPARSE_YUV_TILED_HEADER = 0x0800000000002071;
    ARM_AFBC_16X16_SPLIT_BLOCK_SPARSE_YUV_TE_TILED_HEADER = 0x0800000000003071;

    GOOGLE_GOLDFISH_OPTIMAL = 0x6700000000000001;
};

//
// All complete and valid values below here are deprecated (though not all are
// marked as such yet, due to requirement that added != deprecated). Only
// bitfield values (in contrast to complete values) will remain below here after
// deprecation / removal of complete values below here is done.
//

// Per-vendor upper byte vendor-codes.
@available(added=19)
const FORMAT_MODIFIER_VENDOR_INTEL uint64 = 0x0100000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_AMD uint64 = 0x0200000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_NVIDIA uint64 = 0x0300000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_SAMSUNG uint64 = 0x0400000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_QCOM uint64 = 0x0500000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_VIVANTE uint64 = 0x0600000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_BROADCOM uint64 = 0x0700000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_ARM uint64 = 0x0800000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_ALLWINNER uint64 = 0x0900000000000000;
@available(added=19)
const FORMAT_MODIFIER_VENDOR_AMLOGIC uint64 = 0x0a00000000000000;
// Avoid unilaterally allocating vendor numbers from 0x0b onwards, to hopefully
// avoid collisions with vendor numbers allocated elsewhere and to allow for
// "compatible" values (see below), at least for now.

// The 0x67 is 'g'. The intent of this vendor number is to avoid collision with
// sequentially-allocated vendor numbers allocated elsewhere and listed above,
// at least for now.
@available(added=19)
const FORMAT_MODIFIER_VENDOR_GOOGLE uint64 = 0x6700000000000000;

//
// Within/under a particular FORMAT_MODIFIER_VENDOR_* byte, the remaining bits
// of the format modifier value can include some bitfields that have consistent
// meaning within/under that specific vendor byte.
//
// Fill in (compatible) bitfield/mask values below as needed. These bitfield
// values/masks can be used to build or interpret a complete format modifier.
// These values aren't complete format modifiers on their own. Complete format
// modifiers go in the PixelFormatModifier enum above (but only those which are
// actually used / actually useful, not just every possible combination of
// semantically valid bitfield values).
//
// We define bitfield/mask values here to make it easier for code to check the
// relevant bitfield(s), easier to mask away a feature bit, and similar. These
// are generally defined only within/under the relevant FORMAT_MODIFIER_VENDOR_*
// byte, so each should contain the relevant vendor name.
//

// Intel format modifier bitfield values / masks

/// Format has a color control surface after the tile data
const FORMAT_MODIFIER_INTEL_CCS_BIT uint64 = 0x1000000;

// AMD format modifier bitfield values / masks

// NVIDIA format modifier bitfield values / masks

// SAMSUNG format modifier bitfield values / masks

// QCOM format modifier bitfield values / masks

// VIVANTE format modifier bitfield values / masks

// BROADCOM format modifier bitfield values / masks

// ARM format modifier bitfield values / masks
// bit 0x10 is for using the YUV transform.
const FORMAT_MODIFIER_ARM_YUV_BIT uint64 = 0x10;
// bit 0x20 is for split-block formats.
const FORMAT_MODIFIER_ARM_SPLIT_BLOCK_BIT uint64 = 0x20;
// bit 0x40 is for sparse formats.
const FORMAT_MODIFIER_ARM_SPARSE_BIT uint64 = 0x40;
// bit 0x800 is for variants with buffer content hints.
const FORMAT_MODIFIER_ARM_BCH_BIT uint64 = 0x800;
// bit 0x1000 is for variants with a transaction elimination buffer allocated.
const FORMAT_MODIFIER_ARM_TE_BIT uint64 = 0x1000;
// bit 0x2000 is for variants with tiled headers.
const FORMAT_MODIFIER_ARM_TILED_HEADER_BIT uint64 = 0x2000;