[PATCH v2 05/11] drm/i915/dsb: add intel_dsb_gosub_finish()

[Chaitanya Kumar Borah]

A DSB buffer which will be used for GOSUB execution does not need
the DEWAKE mechanism but still need to be 64 bit aligned. Add helper
to finish preparation of a dsb buffer to be executed with GOSUB
instruction.

v2: Add a cacheline of noops at the end of GOSUB buffer (Ville)

Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dsb.c | 13 +++++++++++++
 drivers/gpu/drm/i915/display/intel_dsb.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 2cda6fc7857b..97ea3c655590 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -585,6 +585,19 @@ void intel_dsb_gosub(struct intel_dsb *dsb,
 	intel_dsb_align_tail(dsb);
 }
 
+void intel_dsb_gosub_finish(struct intel_dsb *dsb)
+{
+	intel_dsb_align_tail(dsb);
+
+	/*
+	 * "All subroutines called by the GOSUB instruction
+	 *  must end with a cacheline of NOPs"
+	 */
+	intel_dsb_noop(dsb, 8);
+
+	intel_dsb_buffer_flush_map(&dsb->dsb_buf);
+}
+
 void intel_dsb_finish(struct intel_dsb *dsb)
 {
 	struct intel_crtc *crtc = dsb->crtc;
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h
index 8b2cf0a7b7e6..6900acd603b8 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.h
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -31,6 +31,7 @@ struct intel_dsb *intel_dsb_prepare(struct intel_atomic_state *state,
 				    enum intel_dsb_id dsb_id,
 				    unsigned int max_cmds);
 void intel_dsb_finish(struct intel_dsb *dsb);
+void intel_dsb_gosub_finish(struct intel_dsb *dsb);
 void intel_dsb_cleanup(struct intel_dsb *dsb);
 void intel_dsb_reg_write(struct intel_dsb *dsb,
 			 i915_reg_t reg, u32 val);
-- 
2.25.1