[PATCH v2 07/13] drm/i915: Extract intel_dsb_supported()

[Ville Syrjala <ville.syrjala@linux.intel.com>]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Extract the "do we have a DSB and should be use it?" check
into a helper. This mirrors intel_flipq_supported() and should
help unify the logic around selecting the codepath which will
be used to perform the commit (mmio vs. DSB. vs. flip queue).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dsb.c | 13 +++++++++----
 drivers/gpu/drm/i915/display/intel_dsb.h |  1 +
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index d9a270362a82..8e01e1eed291 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -1025,6 +1025,14 @@ void intel_dsb_wait(struct intel_dsb *dsb)
 			  dsb_error_int_status(display) | DSB_PROG_INT_STATUS);
 }
 
+bool intel_dsb_supported(struct intel_display *display)
+{
+	if (!display->params.enable_dsb)
+		return false;
+
+	return HAS_DSB(display);
+}
+
 /**
  * intel_dsb_prepare() - Allocate, pin and map the DSB command buffer.
  * @state: the atomic state
@@ -1049,10 +1057,7 @@ struct intel_dsb *intel_dsb_prepare(struct intel_atomic_state *state,
 	struct intel_dsb *dsb;
 	unsigned int size;
 
-	if (!HAS_DSB(display))
-		return NULL;
-
-	if (!display->params.enable_dsb)
+	if (!intel_dsb_supported(display))
 		return NULL;
 
 	dsb = kzalloc_obj(*dsb);
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h
index 3dcca9ed5371..87d9c90da08f 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.h
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -26,6 +26,7 @@ enum intel_dsb_id {
 	I915_MAX_DSBS,
 };
 
+bool intel_dsb_supported(struct intel_display *display);
 unsigned int intel_dsb_size(struct intel_dsb *dsb);
 unsigned int intel_dsb_head(struct intel_dsb *dsb);
 struct intel_dsb *intel_dsb_prepare(struct intel_atomic_state *state,
-- 
2.54.0