[PATCH 11/15] drm/i915/dsc: Add intel_dsc_get_slice_config()

[Imre Deak <imre.deak@intel.com>]

Add intel_dsc_get_slice_config() and move the logic to select a given
slice configuration to that function from the configuration loop in
intel_dp_dsc_get_slice_count(). The same functionality can be used by
other outputs like DSI as well, done as a follow-up.

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c   | 22 ++++-------
 drivers/gpu/drm/i915/display/intel_vdsc.c | 48 +++++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vdsc.h |  4 ++
 3 files changed, 59 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index eff4ea998a948..1d6009b994977 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1030,28 +1030,20 @@ u8 intel_dp_dsc_get_slice_count(const struct intel_connector *connector,
 	 * TGL+: 2x4 (TODO: Add support for this)
 	 */
 	for (slices_per_pipe = 1; slices_per_pipe <= 4; slices_per_pipe++) {
-		int slices_per_line = slices_per_pipe * num_joined_pipes;
+		struct intel_dsc_slice_config config;
+		int slices_per_line;
 
-		/*
-		 * 3 DSC Slices per pipe need 3 DSC engines, which is supported only
-		 * with Ultrajoiner only for some platforms.
-		 */
-		if (slices_per_pipe == 3 &&
-		    (!HAS_DSC_3ENGINES(display) || num_joined_pipes != 4))
+		if (!intel_dsc_get_slice_config(display,
+						num_joined_pipes, slices_per_pipe,
+						&config))
 			continue;
 
+		slices_per_line = intel_dsc_line_slice_count(&config);
+
 		if (!(drm_dp_dsc_slice_count_to_mask(slices_per_line) &
 		      sink_slice_count_mask))
 			continue;
 
-		 /*
-		  * Bigjoiner needs small joiner to be enabled.
-		  * So there should be at least 2 dsc slices per pipe,
-		  * whenever bigjoiner is enabled.
-		  */
-		if (num_joined_pipes > 1 && slices_per_pipe < 2)
-			continue;
-
 		if (mode_hdisplay % slices_per_line)
 			continue;
 
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
index d213947103b51..fd3b4fc85e557 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -40,6 +40,54 @@ int intel_dsc_line_slice_count(const struct intel_dsc_slice_config *config)
 	return config->pipes_per_line * config->streams_per_pipe * config->slices_per_stream;
 }
 
+bool intel_dsc_get_slice_config(struct intel_display *display,
+				int pipes_per_line, int slices_per_pipe,
+				struct intel_dsc_slice_config *config)
+{
+	int streams_per_pipe;
+
+	/* TODO: Add support for 8 slices per pipe on TGL+. */
+	switch (slices_per_pipe) {
+	case 3:
+		/*
+		 * 3 DSC Slices per pipe need 3 DSC engines, which is supported only
+		 * with Ultrajoiner only for some platforms.
+		 */
+		if (!HAS_DSC_3ENGINES(display) || pipes_per_line != 4)
+			return false;
+
+		streams_per_pipe = 3;
+		break;
+	case 4:
+		/* TODO: Consider using 1 DSC engine stream x 4 slices instead. */
+	case 2:
+		/* TODO: Consider using 1 DSC engine stream x 2 slices instead. */
+		streams_per_pipe = 2;
+		break;
+	case 1:
+		 /*
+		  * Bigjoiner needs small joiner to be enabled.
+		  * So there should be at least 2 dsc slices per pipe,
+		  * whenever bigjoiner is enabled.
+		  */
+		if (pipes_per_line > 1)
+			return false;
+
+		streams_per_pipe = 1;
+		break;
+	default:
+		MISSING_CASE(slices_per_pipe);
+		return false;
+	}
+
+	config->pipes_per_line = pipes_per_line;
+	config->streams_per_pipe = streams_per_pipe;
+	config->slices_per_stream = slices_per_pipe / streams_per_pipe;
+
+	return true;
+}
+
+
 static bool is_pipe_dsc(struct intel_crtc *crtc, enum transcoder cpu_transcoder)
 {
 	struct intel_display *display = to_intel_display(crtc);
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.h b/drivers/gpu/drm/i915/display/intel_vdsc.h
index e61116d5297c8..aeb17670307b1 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.h
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.h
@@ -13,11 +13,15 @@ struct drm_printer;
 enum transcoder;
 struct intel_crtc;
 struct intel_crtc_state;
+struct intel_display;
 struct intel_dsc_slice_config;
 struct intel_encoder;
 
 bool intel_dsc_source_support(const struct intel_crtc_state *crtc_state);
 int intel_dsc_line_slice_count(const struct intel_dsc_slice_config *config);
+bool intel_dsc_get_slice_config(struct intel_display *display,
+				int num_joined_pipes, int slice_per_pipe,
+				struct intel_dsc_slice_config *config);
 void intel_uncompressed_joiner_enable(const struct intel_crtc_state *crtc_state);
 void intel_dsc_enable(const struct intel_crtc_state *crtc_state);
 void intel_dsc_disable(const struct intel_crtc_state *crtc_state);
-- 
2.49.1