sdk/fidl/fuchsia.sysmem2/usages.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.sysmem2;

// TODO(fxb/32119): The definitions in this file aren't final and shouldn't yet
// be used in any FIDL protocol.

// Describes how a client will access the contents of a buffer.
table BufferUsage {
    1: uint32 none;
    2: uint32 cpu;
    3: uint32 vulkan;
    4: uint32 display;
    5: uint32 video;
};

// Flag for "none" usage.
//
// This bit indicates that there is no direct usage from the participant, and
// that the participant hasn't forgotten to set usage.
const uint32 NONE_USAGE = 1;

// Flags for "cpu" usage.
// The "often" variants prefer cacheable memory.
const uint32 CPU_USAGE_READ = 1;
const uint32 CPU_USAGE_READ_OFTEN = 2;
const uint32 CPU_USAGE_WRITE = 4;
const uint32 CPU_USAGE_WRITE_OFTEN = 8;

// Flags for "vulkan" usage.
// Based on https://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/VkImageUsageFlagBits.html
const uint32 VULKAN_USAGE_TRANSFER_SRC = 0x0001;
const uint32 VULKAN_USAGE_TRANSFER_DST = 0x0002;
const uint32 VULKAN_USAGE_SAMPLED = 0x0004;
const uint32 VULKAN_USAGE_STORAGE = 0x0008;
const uint32 VULKAN_USAGE_COLOR_ATTACHMENT = 0x0010;
const uint32 VULKAN_USAGE_STENCIL_ATTACHMENT = 0x0020;
const uint32 VULKAN_USAGE_TRANSIENT_ATTACHMENT = 0x0040;
const uint32 VULKAN_USAGE_INPUT_ATTACHMENT = 0x0080;

// Flags for "display" usage.
const uint32 DISPLAY_USAGE_LAYER = 1;
const uint32 DISPLAY_USAGE_CURSOR = 2;

// Flags for "video" usage.
// TODO(ZX-2259): Add more specific HwDecoder flags if needed.
const uint32 VIDEO_USAGE_HW_DECODER = 1;
const uint32 VIDEO_USAGE_HW_ENCODER = 2;
// TODO(34192): This bit is redundant with secure_required and supported heaps.  This bit will
// not be carried forward.
const uint32 VIDEO_USAGE_HW_PROTECTED = 4;
const uint32 VIDEO_USAGE_CAPTURE = 8;
// videoUsageDecryptorOutput is for the output of a decryptor; such buffers will contain decrypted
// encoded access units.  The decryptor output may be in secure memory (controlled separately via
// secure_required).
//
// TODO(34192): Overhaul usage so we can add usage categories without breaking client struct init
// code repeatedly.  For now, this value is in the "video" category but to some degree isn't really
// video; this usage can be used for the output of any secure decryptor.  Also, other usages should
// include input vs. output as those are separate buffer collections and are really separate usages.
//
// We have this as a separate usage because each participant that needs VMO handles needs to specify
// a usage that isn't nonUsage, and the decryptor output participant shouldn't be specifying
// videoUsageHwDecoder because the decryptor isn't the decoder.
const uint32 VIDEO_USAGE_DECRYPTOR_OUTPUT = 16;
// This usage is for a HW video decoder's internal buffers that aren't shared with other
// particpants.  These are allocated via sysmem becuase sysmem pre-reserves contiguous SYSTEM_RAM
// as appropriate, and is the only way to allocate secure memory.
const uint32 VIDEO_USAGE_HW_DECODER_INTERNAL = 32;