drm/i915: Split the ringbuffers from the rings (2/3)

This refactoring has been performed using the following Coccinelle
semantic script:

    @@
    struct intel_engine_cs r;
    @@
    (
    - (r).obj
    + r.buffer->obj
    |
    - (r).virtual_start
    + r.buffer->virtual_start
    |
    - (r).head
    + r.buffer->head
    |
    - (r).tail
    + r.buffer->tail
    |
    - (r).space
    + r.buffer->space
    |
    - (r).size
    + r.buffer->size
    |
    - (r).effective_size
    + r.buffer->effective_size
    |
    - (r).last_retired_head
    + r.buffer->last_retired_head
    )

    @@
    struct intel_engine_cs *r;
    @@
    (
    - (r)->obj
    + r->buffer->obj
    |
    - (r)->virtual_start
    + r->buffer->virtual_start
    |
    - (r)->head
    + r->buffer->head
    |
    - (r)->tail
    + r->buffer->tail
    |
    - (r)->space
    + r->buffer->space
    |
    - (r)->size
    + r->buffer->size
    |
    - (r)->effective_size
    + r->buffer->effective_size
    |
    - (r)->last_retired_head
    + r->buffer->last_retired_head
    )

    @@
    expression E;
    @@
    (
    - LP_RING(E)->obj
    + LP_RING(E)->buffer->obj
    |
    - LP_RING(E)->virtual_start
    + LP_RING(E)->buffer->virtual_start
    |
    - LP_RING(E)->head
    + LP_RING(E)->buffer->head
    |
    - LP_RING(E)->tail
    + LP_RING(E)->buffer->tail
    |
    - LP_RING(E)->space
    + LP_RING(E)->buffer->space
    |
    - LP_RING(E)->size
    + LP_RING(E)->buffer->size
    |
    - LP_RING(E)->effective_size
    + LP_RING(E)->buffer->effective_size
    |
    - LP_RING(E)->last_retired_head
    + LP_RING(E)->buffer->last_retired_head
    )

Note: On top of this this patch also removes the now unused ringbuffer
fields in intel_engine_cs.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
[danvet: Add note about fixup patch included here.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index a0ac668..c26def08 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -91,28 +91,11 @@
 #define I915_NUM_RINGS 5
 #define LAST_USER_RING (VECS + 1)
 	u32		mmio_base;
-	void		__iomem *virtual_start;
 	struct		drm_device *dev;
-	struct		drm_i915_gem_object *obj;
 	struct intel_ringbuffer *buffer;
 
-	u32		head;
-	u32		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;
-
 	unsigned irq_refcount; /* protected by dev_priv->irq_lock */
 	u32		irq_enable_mask;	/* bitmask to enable ring interrupt */
 	u32		trace_irq_seqno;
@@ -239,7 +222,7 @@
 static inline bool
 intel_ring_initialized(struct intel_engine_cs *ring)
 {
-	return ring->buffer && ring->obj;
+	return ring->buffer && ring->buffer->obj;
 }
 
 static inline unsigned
@@ -310,12 +293,12 @@
 static inline void intel_ring_emit(struct intel_engine_cs *ring,
 				   u32 data)
 {
-	iowrite32(data, ring->virtual_start + ring->tail);
-	ring->tail += 4;
+	iowrite32(data, ring->buffer->virtual_start + ring->buffer->tail);
+	ring->buffer->tail += 4;
 }
 static inline void intel_ring_advance(struct intel_engine_cs *ring)
 {
-	ring->tail &= ring->size - 1;
+	ring->buffer->tail &= ring->buffer->size - 1;
 }
 void __intel_ring_advance(struct intel_engine_cs *ring);
 
@@ -335,7 +318,7 @@
 
 static inline u32 intel_ring_get_tail(struct intel_engine_cs *ring)
 {
-	return ring->tail;
+	return ring->buffer->tail;
 }
 
 static inline u32 intel_ring_get_seqno(struct intel_engine_cs *ring)