106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
/*
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* Copyright 2021 Google LLC
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* SPDX-License-Identifier: MIT
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*/
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#ifndef VN_RING_H
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#define VN_RING_H
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#include "vn_common.h"
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/**
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* A ring is a single-producer and single-consumer circular buffer. The data
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* in the buffer are produced and consumed in order. An externally-defined
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* mechanism is required for ring setup and notifications in both directions.
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* Notifications for new data from the producer are needed only when the
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* consumer is not actively polling, which is indicated by the ring status.
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*
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* For venus, the data are plain venus commands. When a venus command is
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* consumed from the ring's perspective, there can still be ongoing CPU and/or
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* GPU works. This is not an issue when the works generated by following
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* venus commands are correctly queued after the ongoing works. There are
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* also venus commands that facilitate polling or waiting for ongoing works.
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*/
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/* the layout of a ring in a shmem */
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struct vn_ring_layout {
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size_t head_offset;
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size_t tail_offset;
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size_t status_offset;
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size_t buffer_offset;
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size_t buffer_size;
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size_t extra_offset;
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size_t extra_size;
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size_t shmem_size;
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};
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static_assert(ATOMIC_INT_LOCK_FREE == 2 && sizeof(atomic_uint) == 4,
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"vn_ring_shared requires lock-free 32-bit atomic_uint");
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/* pointers to a ring in a BO */
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struct vn_ring_shared {
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const volatile atomic_uint *head;
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volatile atomic_uint *tail;
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const volatile atomic_uint *status;
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void *buffer;
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void *extra;
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};
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struct vn_ring_submit {
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uint32_t seqno;
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struct list_head head;
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/* BOs to keep alive (TODO make sure shmems are pinned) */
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uint32_t shmem_count;
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struct vn_renderer_shmem *shmems[];
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};
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struct vn_ring {
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struct vn_renderer *renderer;
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/* TODO assume large ring support and use fixed size */
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uint32_t buffer_size;
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uint32_t buffer_mask;
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struct vn_ring_shared shared;
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uint32_t cur;
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struct list_head submits;
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struct list_head free_submits;
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};
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void
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vn_ring_get_layout(size_t buf_size,
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size_t extra_size,
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struct vn_ring_layout *layout);
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void
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vn_ring_init(struct vn_ring *ring,
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struct vn_renderer *renderer,
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const struct vn_ring_layout *layout,
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void *shared);
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void
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vn_ring_fini(struct vn_ring *ring);
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struct vn_ring_submit *
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vn_ring_get_submit(struct vn_ring *ring, uint32_t shmem_count);
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bool
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vn_ring_submit(struct vn_ring *ring,
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struct vn_ring_submit *submit,
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const struct vn_cs_encoder *cs,
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uint32_t *seqno);
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void
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vn_ring_wait(const struct vn_ring *ring, uint32_t seqno);
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void
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vn_ring_wait_all(const struct vn_ring *ring);
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#endif /* VN_RING_H */
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