[PATCH v2 10/14] drm/i915: prepare scaler for YCBCR420 modeset

[Shashank Sharma]

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.
V6: rebase
V7: Do not create a new scaler user, use existing pipe scaler user.

Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Ander Conselvan De Oliveira <conselvan2 at gmail.com>

Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |  3 +++
 drivers/gpu/drm/i915/intel_drv.h     |  4 +++-
 drivers/gpu/drm/i915/intel_hdmi.c    | 12 ++++++++++++
 drivers/gpu/drm/i915/intel_panel.c   |  3 ++-
 4 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a5140e4..d78f1c2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4624,6 +4624,9 @@ skl_update_scaler(struct intel_crtc_state *crtc_state, bool force_detach,
 	 */
 	need_scaling = src_w != dst_w || src_h != dst_h;
 
+	if (crtc_state->ycbcr420 && scaler_user == SKL_CRTC_INDEX)
+		need_scaling = true;
+
 	/*
 	 * Scaling/fitting not supported in IF-ID mode in GEN9+
 	 * TODO: Interlace fetch mode doesn't support YUV420 planar formats.
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 592243b..94ea6ed 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 +485,7 @@ struct intel_crtc_scaler_state {
 	 * avilability.
 	 */
 #define SKL_CRTC_INDEX 31
+
 	unsigned scaler_users;
 
 	/* scaler used by crtc for panel fitting purpose */
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index eb6243c..49f4fb8 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1356,6 +1356,7 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
 			       struct intel_crtc_state *config,
 			       int *clock_12bpc, int *clock_8bpc)
 {
+	struct intel_crtc *intel_crtc = to_intel_crtc(config->base.crtc);
 
 	if (!connector->ycbcr_420_allowed) {
 		DRM_ERROR("Platform doesn't support YCBCR420 output\n");
@@ -1367,6 +1368,17 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
 	*clock_12bpc /= 2;
 	*clock_8bpc /= 2;
 	config->ycbcr420 = true;
+
+	/* YCBCR 420 output conversion needs a scaler */
+	if (skl_update_scaler_crtc(config)) {
+		DRM_ERROR("Scaler allocation for output failed\n");
+		return false;
+	}
+
+	/* Bind this scaler to pipe */
+	intel_pch_panel_fitting(intel_crtc, config,
+				DRM_MODE_SCALE_FULLSCREEN);
+
 	return true;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 96c2cbd..fd2e081 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->ycbcr420)
 		goto done;
 
 	switch (fitting_mode) {
-- 
2.7.4