[PATCH 04/13] drm/i915/dsb: Enable programmable DSB interrupt

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

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

The DSB can signal a programmable interrupt in response to
a specific DSB command getting executed. Hook that up.

For now we'll just use this to signal the completion of the
commit via a vblank event. If, in the future, we'll need to
do other things in response to DSB interrupts we may need to
come up with some kind of fancier DSB interrupt framework where
the caller can specify a custom handler...

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  2 ++
 drivers/gpu/drm/i915/display/intel_dsb.c      | 27 +++++++++++++++++--
 drivers/gpu/drm/i915/display/intel_dsb.h      |  1 +
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d98bcda16edf..1af74c224f86 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1488,6 +1488,8 @@ struct intel_crtc {
 
 	/* armed event for async flip */
 	struct drm_pending_vblank_event *flip_done_event;
+	/* armed event for DSB based updates */
+	struct drm_pending_vblank_event *dsb_event;
 
 	/* Access to these should be protected by dev_priv->irq_lock. */
 	bool cpu_fifo_underrun_disabled;
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index a14b0230a4f4..6de33c0c16c3 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -379,6 +379,12 @@ void intel_dsb_nonpost_end(struct intel_dsb *dsb)
 	intel_dsb_noop(dsb, 4);
 }
 
+void intel_dsb_interrupt(struct intel_dsb *dsb)
+{
+	intel_dsb_emit(dsb, 0,
+		       DSB_OPCODE_INTERRUPT << DSB_OPCODE_SHIFT);
+}
+
 static void intel_dsb_emit_wait_dsl(struct intel_dsb *dsb,
 				    u32 opcode, int lower, int upper)
 {
@@ -544,7 +550,7 @@ static void _intel_dsb_chain(struct intel_atomic_state *state,
 
 	intel_dsb_reg_write(dsb, DSB_INTERRUPT(pipe, chained_dsb->id),
 			    dsb_error_int_status(display) | DSB_PROG_INT_STATUS |
-			    dsb_error_int_en(display));
+			    dsb_error_int_en(display) | DSB_PROG_INT_EN);
 
 	if (ctrl & DSB_WAIT_FOR_VBLANK) {
 		int dewake_scanline = dsb_dewake_scanline_start(state, crtc);
@@ -612,7 +618,7 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
 
 	intel_de_write_fw(display, DSB_INTERRUPT(pipe, dsb->id),
 			  dsb_error_int_status(display) | DSB_PROG_INT_STATUS |
-			  dsb_error_int_en(display));
+			  dsb_error_int_en(display) | DSB_PROG_INT_EN);
 
 	intel_de_write_fw(display, DSB_HEAD(pipe, dsb->id),
 			  intel_dsb_buffer_ggtt_offset(&dsb->dsb_buf));
@@ -779,6 +785,23 @@ void intel_dsb_irq_handler(struct intel_display *display,
 	tmp = intel_de_read_fw(display, DSB_INTERRUPT(pipe, dsb_id));
 	intel_de_write_fw(display, DSB_INTERRUPT(pipe, dsb_id), tmp);
 
+	if (tmp & DSB_PROG_INT_STATUS) {
+		spin_lock(&display->drm->event_lock);
+
+		if (crtc->dsb_event) {
+			/*
+			 * Update vblank counter/timestmap in case it
+			 * hasn't been done yet for this frame.
+			 */
+			drm_crtc_accurate_vblank_count(&crtc->base);
+
+			drm_crtc_send_vblank_event(&crtc->base, crtc->dsb_event);
+			crtc->dsb_event = NULL;
+		}
+
+		spin_unlock(&display->drm->event_lock);
+	}
+
 	errors = tmp & dsb_error_int_status(display);
 	if (errors)
 		drm_err(display->drm, "[CRTC:%d:%s] DSB %d error interrupt: 0x%x\n",
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h
index c352c12aa59f..ff3b89dfffc1 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.h
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -39,6 +39,7 @@ void intel_dsb_reg_write_masked(struct intel_dsb *dsb,
 void intel_dsb_noop(struct intel_dsb *dsb, int count);
 void intel_dsb_nonpost_start(struct intel_dsb *dsb);
 void intel_dsb_nonpost_end(struct intel_dsb *dsb);
+void intel_dsb_interrupt(struct intel_dsb *dsb);
 void intel_dsb_wait_scanline_in(struct intel_atomic_state *state,
 				struct intel_dsb *dsb,
 				int lower, int upper);
-- 
2.44.2