drm/i915: Allow mmio updates on all platforms, v2.

With intel_pipe_update begin/end we ensure that the mmio updates
don't run during vblank interrupt, using the hw counter we can
be sure that when current vblank count != vblank count at the time
of pipe_update_end the mmio update is complete.

This allows us to use mmio updates on all platforms, using the
update_plane call.

With Chris Wilson's patch to skip waiting for vblanks for
legacy_cursor_update this potentially leaves a small race
condition, in which update_plane can be called with a freed
crtc_state. Because of this commit acf4e84d61673
("drm/i915: Avoid stalling on pending flips for legacy cursor updates")
is temporarily reverted.

Changes since v1:
- Split out the flip_work rename.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-9-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -11269,9 +11269,6 @@ static bool use_mmio_flip(struct intel_engine_cs *engine,
 	if (engine == NULL)
 		return true;
 
-	if (INTEL_GEN(engine->i915) < 5)
-		return false;
-
 	if (i915.use_mmio_flip < 0)
 		return false;
 	else if (i915.use_mmio_flip > 0)
@@ -11286,92 +11283,15 @@ static bool use_mmio_flip(struct intel_engine_cs *engine,
 		return engine != i915_gem_request_get_engine(obj->last_write_req);
 }
 
-static void skl_do_mmio_flip(struct intel_crtc *intel_crtc,
-			     unsigned int rotation,
-			     struct intel_flip_work *work)
-{
-	struct drm_device *dev = intel_crtc->base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_framebuffer *fb = intel_crtc->base.primary->fb;
-	const enum pipe pipe = intel_crtc->pipe;
-	u32 ctl, stride, tile_height;
-
-	ctl = I915_READ(PLANE_CTL(pipe, 0));
-	ctl &= ~PLANE_CTL_TILED_MASK;
-	switch (fb->modifier[0]) {
-	case DRM_FORMAT_MOD_NONE:
-		break;
-	case I915_FORMAT_MOD_X_TILED:
-		ctl |= PLANE_CTL_TILED_X;
-		break;
-	case I915_FORMAT_MOD_Y_TILED:
-		ctl |= PLANE_CTL_TILED_Y;
-		break;
-	case I915_FORMAT_MOD_Yf_TILED:
-		ctl |= PLANE_CTL_TILED_YF;
-		break;
-	default:
-		MISSING_CASE(fb->modifier[0]);
-	}
-
-	/*
-	 * The stride is either expressed as a multiple of 64 bytes chunks for
-	 * linear buffers or in number of tiles for tiled buffers.
-	 */
-	if (intel_rotation_90_or_270(rotation)) {
-		/* stride = Surface height in tiles */
-		tile_height = intel_tile_height(dev_priv, fb->modifier[0], 0);
-		stride = DIV_ROUND_UP(fb->height, tile_height);
-	} else {
-		stride = fb->pitches[0] /
-			intel_fb_stride_alignment(dev_priv, fb->modifier[0],
-						  fb->pixel_format);
-	}
-
-	/*
-	 * Both PLANE_CTL and PLANE_STRIDE are not updated on vblank but on
-	 * PLANE_SURF updates, the update is then guaranteed to be atomic.
-	 */
-	I915_WRITE(PLANE_CTL(pipe, 0), ctl);
-	I915_WRITE(PLANE_STRIDE(pipe, 0), stride);
-
-	I915_WRITE(PLANE_SURF(pipe, 0), work->gtt_offset);
-	POSTING_READ(PLANE_SURF(pipe, 0));
-}
-
-static void ilk_do_mmio_flip(struct intel_crtc *intel_crtc,
-			     struct intel_flip_work *work)
-{
-	struct drm_device *dev = intel_crtc->base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_framebuffer *intel_fb =
-		to_intel_framebuffer(intel_crtc->base.primary->fb);
-	struct drm_i915_gem_object *obj = intel_fb->obj;
-	i915_reg_t reg = DSPCNTR(intel_crtc->plane);
-	u32 dspcntr;
-
-	dspcntr = I915_READ(reg);
-
-	if (obj->tiling_mode != I915_TILING_NONE)
-		dspcntr |= DISPPLANE_TILED;
-	else
-		dspcntr &= ~DISPPLANE_TILED;
-
-	I915_WRITE(reg, dspcntr);
-
-	I915_WRITE(DSPSURF(intel_crtc->plane), work->gtt_offset);
-	POSTING_READ(DSPSURF(intel_crtc->plane));
-}
-
 static void intel_mmio_flip_work_func(struct work_struct *w)
 {
 	struct intel_flip_work *work =
 		container_of(w, struct intel_flip_work, mmio_work);
 	struct intel_crtc *crtc = to_intel_crtc(work->crtc);
-	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct intel_framebuffer *intel_fb =
-		to_intel_framebuffer(crtc->base.primary->fb);
-	struct drm_i915_gem_object *obj = intel_fb->obj;
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_plane *primary = to_intel_plane(crtc->base.primary);
+	struct drm_i915_gem_object *obj = intel_fb_obj(primary->base.state->fb);
 
 	if (work->flip_queued_req)
 		WARN_ON(__i915_wait_request(work->flip_queued_req,
@@ -11385,13 +11305,9 @@ static void intel_mmio_flip_work_func(struct work_struct *w)
 							    MAX_SCHEDULE_TIMEOUT) < 0);
 
 	intel_pipe_update_start(crtc);
-
-	if (INTEL_GEN(dev_priv) >= 9)
-		skl_do_mmio_flip(crtc, work->rotation, work);
-	else
-		/* use_mmio_flip() retricts MMIO flips to ilk+ */
-		ilk_do_mmio_flip(crtc, work);
-
+	primary->update_plane(&primary->base,
+			      crtc->config,
+			      to_intel_plane_state(primary->base.state));
 	intel_pipe_update_end(crtc, work);
 }
 
@@ -11616,7 +11532,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 	work->gtt_offset = intel_plane_obj_offset(to_intel_plane(primary),
 						  obj, 0);
 	work->gtt_offset += intel_crtc->dspaddr_offset;
-	work->rotation = crtc->primary->state->rotation;
 
 	if (mmio_flip) {
 		INIT_WORK(&work->mmio_work, intel_mmio_flip_work_func);

drivers/gpu/drm/i915/intel_drv.h

@@ -983,7 +983,6 @@ struct intel_flip_work {
 	struct drm_i915_gem_request *flip_queued_req;
 	u32 flip_queued_vblank;
 	u32 flip_ready_vblank;
-	unsigned int rotation;
 };
 
 struct intel_load_detect_pipe {