drm/i915: Add crtc->plane_ids_mask

Add a mask of which planes are available for each pipe. This doesn't
quite work for old platforms with dynamic plane<->pipe assignment, but
as we don't support that sort of stuff (yet) we can get away with it.

The main use I have for this is the for_each_plane_id_on_crtc() macro
for iterating over all possible planes on the crtc. I suppose we could
not add the mask, and instead iterate by comparing intel_plane->pipe
but then we'd need a local intel_plane variable which is just
unnecessary clutter in some cases. But I'm not hung up on this, so if
people prefer the other option I could be convinced to use it.

v2: Use BIT() in the iterator macro too (Paulo)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1479830524-7882-3-git-send-email-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -210,6 +210,10 @@ enum plane_id {
 	I915_MAX_PLANES,
 };
 
+#define for_each_plane_id_on_crtc(__crtc, __p) \
+	for ((__p) = PLANE_PRIMARY; (__p) < I915_MAX_PLANES; (__p)++) \
+		for_each_if ((__crtc)->plane_ids_mask & BIT(__p))
+
 enum port {
 	PORT_NONE = -1,
 	PORT_A = 0,

drivers/gpu/drm/i915/intel_display.c

@@ -15277,6 +15277,7 @@ static int intel_crtc_init(struct drm_i915_private *dev_priv, enum pipe pipe)
 		ret = PTR_ERR(primary);
 		goto fail;
 	}
+	intel_crtc->plane_ids_mask |= BIT(primary->id);
 
 	for_each_sprite(dev_priv, pipe, sprite) {
 		struct intel_plane *plane;
@@ -15286,6 +15287,7 @@ static int intel_crtc_init(struct drm_i915_private *dev_priv, enum pipe pipe)
 			ret = PTR_ERR(plane);
 			goto fail;
 		}
+		intel_crtc->plane_ids_mask |= BIT(plane->id);
 	}
 
 	cursor = intel_cursor_plane_create(dev_priv, pipe);
@@ -15293,6 +15295,7 @@ static int intel_crtc_init(struct drm_i915_private *dev_priv, enum pipe pipe)
 		ret = PTR_ERR(cursor);
 		goto fail;
 	}
+	intel_crtc->plane_ids_mask |= BIT(cursor->id);
 
 	ret = drm_crtc_init_with_planes(&dev_priv->drm, &intel_crtc->base,
 					&primary->base, &cursor->base,

drivers/gpu/drm/i915/intel_drv.h

@@ -691,8 +691,9 @@ struct intel_crtc {
 	 * some outputs connected to this crtc.
 	 */
 	bool active;
-	unsigned long enabled_power_domains;
 	bool lowfreq_avail;
+	u8 plane_ids_mask;
+	unsigned long enabled_power_domains;
 	struct intel_overlay *overlay;
 	struct intel_flip_work *flip_work;