text: /*
   * $FreeBSD: soc2013/dpl/head/sys/dev/drm2/i915/intel_ringbuffer.h 236132 2012-05-22 11:07:44Z kib $
   */
  
  #ifndef _INTEL_RINGBUFFER_H_
  #define _INTEL_RINGBUFFER_H_
  
  struct  intel_hw_status_page {
  	uint32_t	*page_addr;
  	unsigned int	gfx_addr;
  	struct		drm_i915_gem_object *obj;
  };
  
  #define I915_READ_TAIL(ring) I915_READ(RING_TAIL((ring)->mmio_base))
  #define I915_WRITE_TAIL(ring, val) I915_WRITE(RING_TAIL((ring)->mmio_base), val)
  
  #define I915_READ_START(ring) I915_READ(RING_START((ring)->mmio_base))
  #define I915_WRITE_START(ring, val) I915_WRITE(RING_START((ring)->mmio_base), val)
  
  #define I915_READ_HEAD(ring)  I915_READ(RING_HEAD((ring)->mmio_base))
  #define I915_WRITE_HEAD(ring, val) I915_WRITE(RING_HEAD((ring)->mmio_base), val)
  
  #define I915_READ_CTL(ring) I915_READ(RING_CTL((ring)->mmio_base))
  #define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL((ring)->mmio_base), val)
  
  #define I915_READ_IMR(ring) I915_READ(RING_IMR((ring)->mmio_base))
  #define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)
  
  #define I915_READ_NOPID(ring) I915_READ(RING_NOPID((ring)->mmio_base))
  #define I915_READ_SYNC_0(ring) I915_READ(RING_SYNC_0((ring)->mmio_base))
  #define I915_READ_SYNC_1(ring) I915_READ(RING_SYNC_1((ring)->mmio_base))
  
  struct  intel_ring_buffer {
  	const char	*name;
  	enum intel_ring_id {
  		RCS = 0x0,
  		VCS,
  		BCS,
  	} id;
  #define I915_NUM_RINGS 3
  	uint32_t	mmio_base;
  	void		*virtual_start;
  	struct		drm_device *dev;
  	struct		drm_i915_gem_object *obj;
  
  	uint32_t	head;
  	uint32_t	tail;
  	int		space;
  	int		size;
  	int		effective_size;
  	struct intel_hw_status_page status_page;
  
  	/** We track the position of the requests in the ring buffer, and
  	 * when each is retired we increment last_retired_head as the GPU
  	 * must have finished processing the request and so we know we
  	 * can advance the ringbuffer up to that position.
  	 *
  	 * last_retired_head is set to -1 after the value is consumed so
  	 * we can detect new retirements.
  	 */
  	u32		last_retired_head;
  
  	struct mtx	irq_lock;
  	uint32_t	irq_refcount;
  	uint32_t	irq_mask;
  	uint32_t	irq_seqno;		/* last seq seem at irq time */
  	uint32_t	trace_irq_seqno;
  	uint32_t	waiting_seqno;
  	uint32_t	sync_seqno[I915_NUM_RINGS-1];
  	bool		(*irq_get)(struct intel_ring_buffer *ring);
  	void		(*irq_put)(struct intel_ring_buffer *ring);
  
  	int		(*init)(struct intel_ring_buffer *ring);
  
  	void		(*write_tail)(struct intel_ring_buffer *ring,
  				      uint32_t value);
  	int		(*flush)(struct intel_ring_buffer *ring,
  				  uint32_t	invalidate_domains,
  				  uint32_t	flush_domains);
  	int		(*add_request)(struct intel_ring_buffer *ring,
  				       uint32_t *seqno);
  	uint32_t	(*get_seqno)(struct intel_ring_buffer *ring);
  	int		(*dispatch_execbuffer)(struct intel_ring_buffer *ring,
  					       uint32_t offset, uint32_t length);
  	void		(*cleanup)(struct intel_ring_buffer *ring);
  	int		(*sync_to)(struct intel_ring_buffer *ring,
  				   struct intel_ring_buffer *to,
  				   u32 seqno);
   
  	u32		semaphore_register[3]; /*our mbox written by others */
  	u32		signal_mbox[2]; /* mboxes this ring signals to */
  
  	/**
  	 * List of objects currently involved in rendering from the
  	 * ringbuffer.
  	 *
  	 * Includes buffers having the contents of their GPU caches
  	 * flushed, not necessarily primitives.  last_rendering_seqno
  	 * represents when the rendering involved will be completed.
  	 *
  	 * A reference is held on the buffer while on this list.
  	 */
  	struct list_head active_list;
  
  	/**
  	 * List of breadcrumbs associated with GPU requests currently
  	 * outstanding.
  	 */
  	struct list_head request_list;
  
  	/**
  	 * List of objects currently pending a GPU write flush.
  	 *
  	 * All elements on this list will belong to either the
  	 * active_list or flushing_list, last_rendering_seqno can
  	 * be used to differentiate between the two elements.
  	 */
  	struct list_head gpu_write_list;
  
  	/**
  	 * Do we have some not yet emitted requests outstanding?
  	 */
  	uint32_t outstanding_lazy_request;
  
  	drm_local_map_t map;
  
  	void *private;
  };
  
  static inline unsigned
  intel_ring_flag(struct intel_ring_buffer *ring)
  {
  	return 1 << ring->id;
  }
  
  static inline uint32_t
  intel_ring_sync_index(struct intel_ring_buffer *ring,
  		      struct intel_ring_buffer *other)
  {
  	int idx;
  
  	/*
  	 * cs -> 0 = vcs, 1 = bcs
  	 * vcs -> 0 = bcs, 1 = cs,
  	 * bcs -> 0 = cs, 1 = vcs.
  	 */
  
  	idx = (other - ring) - 1;
  	if (idx < 0)
  		idx += I915_NUM_RINGS;
  
  	return idx;
  }
  
  static inline uint32_t
  intel_read_status_page(struct intel_ring_buffer *ring, int reg)
  {
  
  	return (atomic_load_acq_32(ring->status_page.page_addr + reg));
  }
  
  void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);
  
  int intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n);
  static inline int intel_wait_ring_idle(struct intel_ring_buffer *ring)
  {
  
  	return (intel_wait_ring_buffer(ring, ring->size - 8));
  }
  
  int intel_ring_begin(struct intel_ring_buffer *ring, int n);
  
  static inline void intel_ring_emit(struct intel_ring_buffer *ring,
  				   uint32_t data)
  {
  	*(volatile uint32_t *)((char *)ring->virtual_start +
  	    ring->tail) = data;
  	ring->tail += 4;
  }
  
  void intel_ring_advance(struct intel_ring_buffer *ring);
  
  uint32_t intel_ring_get_seqno(struct intel_ring_buffer *ring);
  
  int intel_init_render_ring_buffer(struct drm_device *dev);
  int intel_init_bsd_ring_buffer(struct drm_device *dev);
  int intel_init_blt_ring_buffer(struct drm_device *dev);
  
  u32 intel_ring_get_active_head(struct intel_ring_buffer *ring);
  void intel_ring_setup_status_page(struct intel_ring_buffer *ring);
  
  static inline u32 intel_ring_get_tail(struct intel_ring_buffer *ring)
  {
  	return ring->tail;
  }
  
  void i915_trace_irq_get(struct intel_ring_buffer *ring, uint32_t seqno);
  
  /* DRI warts */
  int intel_render_ring_init_dri(struct drm_device *dev, uint64_t start,
      uint32_t size);
  
  #endif /* _INTEL_RINGBUFFER_H_ */
  