[Intel-gfx] [PATCH 08/15] drm/i915/dsb: Check DSB engine status.

[Animesh Manna]

As per bspec check for DSB status before programming any
of its register. Inline function added to check the dsb status.

Cc: Michel Thierry <michel.thierry at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Animesh Manna <animesh.manna at intel.com>
---
 drivers/gpu/drm/i915/intel_dsb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsb.c b/drivers/gpu/drm/i915/intel_dsb.c
index aa5361c2d70e..9ad4fc8b9f1e 100644
--- a/drivers/gpu/drm/i915/intel_dsb.c
+++ b/drivers/gpu/drm/i915/intel_dsb.c
@@ -23,6 +23,15 @@
 #define DSB_BYTE_EN			(0xf << 20)
 #define DSB_REG_VALUE_MASK		0xfffff
 
+static inline bool is_dsb_busy(struct intel_dsb *dsb)
+{
+	struct intel_crtc *crtc = dsb->crtc;
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	enum pipe pipe = crtc->pipe;
+
+	return DSB_STATUS & I915_READ(DSB_CTRL(pipe, dsb->id));
+}
+
 struct intel_dsb *
 intel_dsb_get(struct intel_crtc *crtc)
 {
-- 
2.21.0