// 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;

const uint32 MAX_COUNT_BUFFER_COLLECTION_CONSTRAINTS_IMAGE_FORMAT_CONSTRAINTS = 64;
const uint32 MAX_COUNT_BUFFER_MEMORY_CONSTRAINTS_HEAP_PERMITTED = 64;
const uint32 MAX_COUNT_IMAGE_FORMAT_CONSTRAINTS_COLOR_SPACES = 32;

// The contents of this file are not final.  Incompatible changes are still
// being made to this file.  Do not rely on the contents of this file to provide
// backward compatibility (yet).
//
// TODO(34192): Sysmem should use llcpp and FIDL tables.  The
// fuchsia.sysmem2.BufferCollectionConstraints defined here are part of that
// transition, but the definitions here are not final.  For now, the definition
// here is only used internally to sysmem (not between processes), and therefore
// this definition can change for now.  Later after we're happy with this
// representation, we'll create
// fuchsia.sysmem2.BufferCollection.SetConstraints() which will accept
// constraints as defined here.

/// Constraints on BufferCollection parameters.  These constraints can be
/// specified per-participant.  The sysmem service implements aggregation of
/// constraints from multiple participants.
table BufferCollectionConstraints {
    /// The usage is only meant as a hint to help sysmem choose a more optimal
    /// PixelFormat or similar when multiple compatible options exist.
    ///
    /// When aggregating BufferCollectionConstraints, these values bitwise-OR.
    ///
    /// At least one usage bit must be specified unless the whole
    /// BufferCollectionConstraints is logically null (no fields set).
    1: BufferUsage usage;

    /// Per-participant minimum number of buffers that are needed for camping
    /// purposes.  A participant should specify a number for min_buffer_count
    /// that's >= the maximum number of buffers that the participant may
    /// concurrently camp on for any non-transient period of time.
    ///
    /// For example, a video decoder would specify (at least) the maximum number
    /// of reference frames + 1 frame currently being decoded into.
    ///
    /// A participant must not camp on more buffers than specified here (except
    /// very transiently) else processing may get stuck.
    ///
    /// When aggregating BufferCollectionConstraints, these values add.
    ///
    /// In testing scenarios, camping on more buffers than this for any
    /// significant duration may (ideally will) be flagged as a failure.  In
    /// testing scenarios, the participant may not be provided with more buffers
    /// than this concurrently.
    2: uint32 min_buffer_count_for_camping;

    /// Per-participant minimum number of buffers that are needed for slack
    /// reasons, for better overlap of processing / better performance.
    ///
    /// When aggregating BufferCollectionConstraints, these values add.
    ///
    /// A participant should typically specify 0 or 1 here - typically 0 is
    /// appropriate if min_buffer_count_for_camping is already enough to keep
    /// the participant busy 100% of the time when the participant is slightly
    /// behind, while 1 can be appropriate if 1 more buffer than strictly needed
    /// for min-camping reasons gives enough slack to stay busy 100% of the time
    /// (when slightly behind, vs. lower % without the extra buffer).
    ///
    /// In testing scenarios, this field may be forced to 0, and all
    /// participants are expected to continue to work without getting stuck.  If
    /// a buffer is needed for forward progress reasons, that buffer should be
    /// accounted for in min_buffer_count_for_camping.
    3: uint32 min_buffer_count_for_dedicated_slack;

    /// Similar to min_buffer_count_for_dedicated_slack, except when aggregating
    /// these values max (instead of add).  The value here is not shared with
    /// any participant's min_buffer_count_for_dedicated_slack.
    ///
    /// A participant can specify > 0 here if a participant would like to ensure
    /// there's some slack overall, but doesn't need that slack to be dedicated.
    ///
    /// The choice whether to use min_buffer_count_for_dedicated_slack or
    /// min_buffer_count_for_shared_slack (or both) will typically be about the
    /// degree to which the extra slack improves performance.
    ///
    /// In testing scenarios, this field may be forced to 0, and all
    /// participants are expected to continue to work without getting stuck.  If
    /// a buffer is needed for forward progress reasons, that buffer should be
    /// accounted for in min_buffer_count_for_camping.
    4: uint32 min_buffer_count_for_shared_slack;

    /// A particularly-picky participant may unfortunately need to demand a tight
    /// range of buffer_count, or even a specific buffer_count.  This field
    /// should remain 0 unless a participant really must set this field to
    /// constrain the overall BufferCollectionInfo_2.buffer_count.  Any such
    /// participant should still fill out the min_buffer_count_for_* fields.
    ///
    /// If this field is un-set, the logical min_buffer_count is 1.
    5: uint32 min_buffer_count;
    /// A particularly-picky participant may unfortunately need to demand a tight
    /// range of buffer_count, or even a specific buffer_count.  This field
    /// should remain 0 unless a participant really must set this field to
    /// constrain the overall BufferCollectionInfo_2.buffer_count.  Any such
    /// participant should still fill out the min_buffer_count_for_* fields.
    ///
    /// If this field is un-set, the logical max_buffer_count is 0xFFFFFFFF.
    6: uint32 max_buffer_count;

    /// Optional constraints on BufferCollectionSettings.buffer_settings.
    ///
    /// A participant that intends to specify image_format_constraints_count > 1
    /// will typically specify the minimum buffer size implicitly via
    /// image_format_constraints, and possibly specify only the max buffer size
    /// via buffer_memory_constraints.
    ///
    /// If un-set, the client is specifying "don't care" re. any buffer memory
    /// constraints.
    7: BufferMemoryConstraints buffer_memory_constraints;

    /// Optional constraints on the image format parameters of an image stored
    /// in a buffer of the BufferCollection.  This includes pixel format and
    /// image layout.  These constraints are per-pixel-format, so more than one
    /// is permitted.
    ///
    /// When aggregating, only pixel formats that are specified by all
    /// particpants with non-zero image_format_constraints_count (and non-Null)
    /// BufferCollectionConstraints) are retained.
    ///
    /// un-set means no image format constraints.  set but zero length is an
    /// error.
    8: vector<ImageFormatConstraints>:MAX_COUNT_BUFFER_COLLECTION_CONSTRAINTS_IMAGE_FORMAT_CONSTRAINTS image_format_constraints;

    /// If true, a secure heap may only be selected if all participants with
    /// BufferMemoryConstraints specify allow_clear_aux_buffers_for_secure.  If
    /// "need" is true, "allow" must also be true.
    ///
    /// If false (or unset), the participant can still work, potentially even
    /// with secure memory (depending on supported heaps), without clear aux
    /// buffers.
    9: bool need_clear_aux_buffers_for_secure;

    /// If true, the participant will use clear aux buffers, if they are
    /// allocated, as appropriate to the participant's role.  If the participant
    /// is a writer, then the participant writer will populate the clear aux
    /// buffers with the clear (not-encrypted, not-DRM-protected) bytes, and
    /// fill protected bytes with data that does not emulate start codes, such
    /// as 0xFF.
    ///
    /// If un-set, then allow_clear_aux_buffers_for_secure is true iff the
    /// participant specifies usage which is read-only.
    ///
    /// If un-set from a participant with write usage, or false, the buffer
    /// collection won't be able to allocate if any participant specifies
    /// need_clear_aux_buffers_for_secure true.
    10: bool allow_clear_aux_buffers_for_secure;
};

/// Known heap types.
/// Device specific types should have bit 60 set. Top order bit is reserved
/// and should not be set.
enum HeapType : uint64 {
    SYSTEM_RAM = 0x0000000000000000;

    /// Heap used for amlogic protected memory.
    AMLOGIC_SECURE = 0x1000000000010000;

    /// Heap used for amlogic protected memory between decrypt and video decode.
    AMLOGIC_SECURE_VDEC = 0x1000000000010001;

    /// Heap used by goldfish vulkan for device-local memory.
    GOLDFISH_DEVICE_LOCAL = 0x1000000000020000;
};

table BufferMemoryConstraints {
    1: uint32 min_size_bytes;
    /// un-set is treated as 0xFFFFFFFF.
    2: uint32 max_size_bytes;

    3: bool physically_contiguous_required;

    /// If true, at least one participant requires secure memory.
    ///
    /// When aggregating BufferCollectionConstraints, these values boolean-OR.
    4: bool secure_required;

    /// By default, participants must ensure the CPU can read or write data to
    /// the buffer without cache operations. If they support using the RAM
    /// domain, data must be available in RAM (with CPU cache state such that
    /// the RAM data won't get corrupted by a dirty CPU cache line writing
    /// incorrect data to RAM), and a consumer reading using the CPU must
    /// invalidate CPU cache before reading (the producer doesn't guarantee
    /// zero stale "clean" cache lines)
    5: bool cpu_domain_supported;
    6: bool ram_domain_supported;
    7: bool inaccessible_domain_supported;

    /// Optional heap constraints. Participants that don't care which heap
    /// memory is allocated on should leave this field un-set.
    8: vector<HeapType>:MAX_COUNT_BUFFER_MEMORY_CONSTRAINTS_HEAP_PERMITTED heap_permitted;
};

/// Inaccessible is only for cases where there is no CPU-based access to the
/// buffers.  A secure_required buffer can still have CoherencyDomain Cpu or
/// Ram even if the secure_required buffer can only be accessed by the CPU when
/// the CPU is running in secure mode (or similar).  In contrast, device-local
/// memory that isn't reachable from the CPU is CoherencyDomain Inaccessible,
/// even if it's possible to cause a device (physical or virtual) to copy the
/// data from the Inaccessible buffers to buffers that are visible to the CPU.
enum CoherencyDomain {
    CPU = 0;
    RAM = 1;
    INACCESSIBLE = 2;
};

/// Describes constraints on layout of image data in buffers.
// TODO(fxb/32119): change struct to table
table ImageFormatConstraints {
    /// The PixelFormat for which the following constraints apply.  A
    /// participant may have more than one PixelFormat that's supported, in
    /// which case that participant can use a list of ImageFormatConstraints
    /// with an entry per PixelFormat.  It's not uncommon for the other fields
    /// of ImageFormatConstraints to vary by PixelFormat - for example for a
    /// linear format to support smaller max size than a tiled format.
    1: PixelFormat pixel_format;

    /// Empty is an error.  Redundant entries are an error.  Arbitrary ordering
    /// is not an error.
    2: vector<ColorSpace>:MAX_COUNT_IMAGE_FORMAT_CONSTRAINTS_COLOR_SPACES color_spaces;

    /// Minimum permitted width in pixels.
    ///
    /// For example a video decoder participant may set this field to the
    /// minimum coded_width that might potentially be specified by a stream.  In
    /// contrast, required_min_coded_width would be set to the current
    /// coded_width specified by the stream.  While min_coded_width aggregates
    /// by taking the max, required_min_coded_width aggregates by taking the
    /// min.
    ///
    /// See also required_min_coded_width.
    3: uint32 min_coded_width;
    /// Maximum width in pixels.  For example Scenic may set this field
    /// (directly or via sub-participants) to the maximum width that can be
    /// composited.
    /// un-set is treated as 0xFFFFFFFF.
    4: uint32 max_coded_width;

    /// Minimum height in pixels.  For example a video decoder participant may
    /// set this field to the coded_height specified by a stream.
    5: uint32 min_coded_height;
    /// Maximum height in pixels.  For example Scenic may set this field
    /// (directly or via sub-participants) to the maximum height that can be
    /// composited.
    /// un-set is treated as 0xFFFFFFFF.
    6: uint32 max_coded_height;

    /// Must be >= the value implied by min_coded_width for plane 0.
    7: uint32 min_bytes_per_row;
    /// Must be >= the value implied by max_coded_width for plane 0.
    /// un-set is treated as 0xFFFFFFFF.
    8: uint32 max_bytes_per_row;

    /// The max image area in pixels is limited indirectly via
    /// BufferSettings.size_bytes, and can also be enforced directly via this
    /// field.
    /// un-set is treated as 0xFFFFFFFF.
    9: uint32 max_coded_width_times_coded_height;

    /// coded_width % width_divisor must be 0.
    /// un-set is treated as 1.
    10: uint32 coded_width_divisor;

    /// coded_height % height_divisor must be 0.
    /// un-set is treated as 1.
    11: uint32 coded_height_divisor;

    /// bytes_per_row % bytes_per_row_divisor must be 0.
    /// un-set is treated as 1.
    12: uint32 bytes_per_row_divisor;

    /// vmo_usable_start % start_offset_divisor must be 0.
    /// un-set is treated as 1.
    13: uint32 start_offset_divisor;

    /// display_width % display_width_divisor must be 0.
    /// un-set is treated as 1.
    14: uint32 display_width_divisor;

    /// display_height % display_height_divisor must be 0.
    /// un-set is treated as 1.
    15: uint32 display_height_divisor;

    /// required_ dimension bounds.
    ///
    /// In contrast to the corresponding fields without "required_" at the
    /// start, these fields (when set to non-zero values) express a requirement
    /// that the resulting aggregated non-required_ fields specify a space that
    /// fully contain the space expressed by each participant's required_
    /// fields.
    ///
    /// For example, a producer video decoder is perfectly happy for the
    /// consumer to be willing to accept anything, and the video decoder doesn't
    /// really want to constrain the potential space of dimensions that might be
    /// seen in a stream and may be acceptable to the consumer, but the video
    /// decoder needs to ensure that the resulting dimension ranges contain
    /// at least the current dimensions decoded from the stream.
    ///
    /// Similarly, an initiator with a particular dynamic-dimension scenario in
    /// mind may wish to require up front that participants agree to handle at
    /// least the range of dimensions expected by the initiator in that
    /// scenario (else fail earlier rather than later, maybe trying again with
    /// smaller required_ space).
    ///
    /// It's much more common for a producer or initiator to set these fields
    /// than for a consumer to set these fields.
    ///
    /// While the non-required_ fields aggregate by taking the intersection, the
    /// required_ fields aggregate by taking the union.
    ///
    /// If set, the required_max_coded_width and required_max_coded_height will
    /// cause the allocated buffers to be large enough to hold an image that is
    /// required_max_coded_width * required_max_coded_height.
    ///
    /// TODO(fxb/34192): Make it easier to allocate buffers of minimal size
    /// that can (optionally) also handle 90 degree rotated version of the max
    /// dimensions / alternate required bounds for another main aspect ratio.
    /// un-set is treated as 0xFFFFFFFF.
    16: uint32 required_min_coded_width;
    17: uint32 required_max_coded_width;
    /// un-set is treated as 0xFFFFFFFF.
    18: uint32 required_min_coded_height;
    19: uint32 required_max_coded_height;
    /// un-set is treated as 0xFFFFFFFF.
    20: uint32 required_min_bytes_per_row;
    21: uint32 required_max_bytes_per_row;
};

/// Describes how an image is represented.
// TODO(fxb/32119): Currently this table is not considered ready for use between
// processes, but should be fairly soon.
table ImageFormat {
    /// Pixel format.
    1: PixelFormat pixel_format;

    /// Row width in pixels that exist in the buffer.  Must be >= display_width.
    /// Can be < the width implied by stride_bytes.
    2: uint32 coded_width;

    /// Number of rows.  Must be >= display_height.
    3: uint32 coded_height;

    // Stride in bytes of plane 0.  Planes beyond plane 0 (if any, depending on
    // pixel_format) have a known fixed relationship with plane 0's stride.
    4: uint32 bytes_per_row;

    /// Row width in pixels that are to be displayed.  This can be <=
    /// coded_width.  Any cropping occurs on the right of the image (not left).
    5: uint32 display_width;

    /// Number of rows to be displayed.  This can be <= coded_height, with any
    /// cropping on the bottom (not top).
    6: uint32 display_height;

    /// Color space.
    7: ColorSpace color_space;

    /// The pixel_aspect_ratio_width : pixel_aspect_ratio_height is the pixel
    /// aspect ratio (AKA sample aspect ratio aka SAR) for the luma (AKA Y)
    /// samples. A pixel_aspect_ratio of 1:1 mean square pixels. A
    /// pixel_aspect_ratio of 2:1 would mean pixels that are displayed twice as
    /// wide as they are tall. Codec implementation should ensure these two
    /// values are relatively prime by reducing the fraction (dividing both by
    /// GCF) if necessary.
    ///
    /// A producer should set both these fields, or neither of them.
    ///
    /// A consumer should interpret either of these fields being un-set as an
    /// unknown pixel_aspect_ratio.  A default of 1:1 can be appropriate in some
    /// cases, but a consumer may determine the actual pixel_aspect_ratio by OOB
    /// means.
    8: uint32 pixel_aspect_ratio_width;
    9: uint32 pixel_aspect_ratio_height;
};