[PATCH v5 13/17] drm/i915: prepare scaler for YCBCR420 modeset

[Shashank Sharma <shashank.sharma@intel.com>]

To get a YCBCR420 output from intel platforms, we need one
scaler to scale down YCBCR444 samples to YCBCR420 samples.

This patch:
- Does scaler allocation for HDMI ycbcr420 outputs.
- Programs PIPE_MISC register for ycbcr420 output.
- Adds a new scaler user "HDMI output" to plug-into existing
  scaler framework. This output type is identified using bit
  30 of the scaler users bitmap.

V2: rebase
V3: rebase
V4: rebase
V5: addressed review comments from Ander:
    - No need to check both scaler_user && hdmi_output.
      Check for scaler_user is enough.

Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Ander Conselvan De Oliveira <conselvan2@gmail.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
---
 drivers/gpu/drm/i915/intel_atomic.c  |  6 ++++++
 drivers/gpu/drm/i915/intel_display.c | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h     | 10 +++++++++-
 drivers/gpu/drm/i915/intel_hdmi.c    | 10 ++++++++++
 drivers/gpu/drm/i915/intel_panel.c   |  3 ++-
 5 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
index 36d4e63..a8c9ac5 100644
--- a/drivers/gpu/drm/i915/intel_atomic.c
+++ b/drivers/gpu/drm/i915/intel_atomic.c
@@ -264,6 +264,12 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
 
 			/* panel fitter case: assign as a crtc scaler */
 			scaler_id = &scaler_state->scaler_id;
+		} else if (i == SKL_HDMI_OUTPUT_INDEX) {
+			name = "HDMI-OUTPUT";
+			idx = intel_crtc->base.base.id;
+
+			/* hdmi output case: needs a pipe scaler */
+			scaler_id = &scaler_state->scaler_id;
 		} else {
 			name = "PLANE";
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 082270d..ee1452e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4621,6 +4621,10 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
 	 */
 	need_scaling = src_w != dst_w || src_h != dst_h;
 
+	if (scaler_user == SKL_HDMI_OUTPUT_INDEX)
+		/* YCBCR 444 -> 420 conversion needs a scaler */
+		need_scaling = true;
+
 	/*
 	 * if plane is being disabled or scaler is no more required or force detach
 	 *  - free scaler binded to this plane/crtc
@@ -4668,6 +4672,26 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
 }
 
 /**
+ * skl_update_scaler_hdmi_output - Stages update to scaler state for HDMI.
+ * HDMI YCBCR 420 output needs a scaler, for downsampling.
+ *
+ * @state: crtc's scaler state
+ *
+ * Return
+ *     0 - scaler_usage updated successfully
+ *    error - requested scaling cannot be supported or other error condition
+ */
+int skl_update_scaler_crtc_hdmi_output(struct intel_crtc_state *state)
+{
+	const struct drm_display_mode *mode = &state->base.adjusted_mode;
+
+	return skl_update_scaler(state, !state->base.active,
+		SKL_HDMI_OUTPUT_INDEX, &state->scaler_state.scaler_id,
+		state->pipe_src_w, state->pipe_src_h,
+		mode->crtc_hdisplay, mode->crtc_vdisplay);
+}
+
+/**
  * skl_update_scaler_crtc - Stages update to scaler state for a given crtc.
  *
  * @state: crtc's scaler state
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index cc25d71..86af283 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -471,7 +471,8 @@ struct intel_crtc_scaler_state {
 	 *
 	 *     If a bit is set, a user is using a scaler.
 	 *     Here user can be a plane or crtc as defined below:
-	 *       bits 0-30 - plane (bit position is index from drm_plane_index)
+	 *       bits 0-29 - plane (bit position is index from drm_plane_index)
+	 *       bit 30    - hdmi output
 	 *       bit 31    - crtc
 	 *
 	 * Instead of creating a new index to cover planes and crtc, using
@@ -484,6 +485,12 @@ struct intel_crtc_scaler_state {
 	 * avilability.
 	 */
 #define SKL_CRTC_INDEX 31
+
+	/*
+	 * HDMI YCBCR 420 output consume a scaler. So adding a user
+	 * for HDMI output 420 requirement.
+	 */
+#define SKL_HDMI_OUTPUT_INDEX 30
 	unsigned scaler_users;
 
 	/* scaler used by crtc for panel fitting purpose */
@@ -1483,6 +1490,7 @@ void intel_mode_from_pipe_config(struct drm_display_mode *mode,
 				 struct intel_crtc_state *pipe_config);
 
 int skl_update_scaler_crtc(struct intel_crtc_state *crtc_state);
+int skl_update_scaler_crtc_hdmi_output(struct intel_crtc_state *state);
 int skl_max_scale(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state);
 
 static inline u32 intel_plane_ggtt_offset(const struct intel_plane_state *state)
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 3a07431..948cbce 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1403,6 +1403,7 @@ intel_hdmi_compute_ycbcr_config(struct drm_connector_state *conn_state,
 	}
 
 	if (type == DRM_HDMI_OUTPUT_YCBCR420) {
+		struct intel_crtc *intel_crtc = to_intel_crtc(conn_state->crtc);
 
 		/* YCBCR420 TMDS rate requirement is half the pixel clock */
 		config->hdmi_output = DRM_HDMI_OUTPUT_YCBCR420;
@@ -1410,6 +1411,15 @@ intel_hdmi_compute_ycbcr_config(struct drm_connector_state *conn_state,
 		*clock_12bpc /= 2;
 		*clock_8bpc /= 2;
 
+		/* YCBCR 420 output conversion needs a scaler */
+		if (skl_update_scaler_crtc_hdmi_output(config)) {
+			DRM_ERROR("Scaler allocation for output failed\n");
+			return DRM_HDMI_OUTPUT_INVALID;
+		}
+
+		/* Bind this scaler to pipe */
+		intel_pch_panel_fitting(intel_crtc, config,
+					DRM_MODE_SCALE_FULLSCREEN);
 	}
 
 	/* Encoder is capable of this output, lets commit to CRTC */
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 96c2cbd..b6a32c4 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -110,7 +110,8 @@ intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
 
 	/* Native modes don't need fitting */
 	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
-	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h)
+	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h &&
+	    pipe_config->hdmi_output != DRM_HDMI_OUTPUT_YCBCR420)
 		goto done;
 
 	switch (fitting_mode) {
-- 
2.7.4

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