[PATCH 6/8] drm/i915/dsc: Add debugfs entry to validate DSC YCbCr420

[Swati Sharma]

DSC_YCBCR420_Sink_Support entry is added to i915_dsc_fec_support_show
to depict if sink supports DSC YCbCr420.
Also, new debugfs entry is created to enforce YCbCr420 output format.
This is required because of our driver policy. If a mode is supported in
both RGB and YCbCr420 output formats by the sink, our policy is to try RGB first
and fall back to YCbCr420, if mode cannot be shown using RGB.
So, to test YCbCr420, we need a debugfs entry (force_dsc_ycbcr420) to force this
output format; so that YCbCr420 code gets executed.

Signed-off-by: Swati Sharma <swati2.sharma at intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  | 84 +++++++++++++++++++
 .../drm/i915/display/intel_display_types.h    |  1 +
 2 files changed, 85 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index cfc056a05bbf..1f051f74a00a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -1770,6 +1770,8 @@ static int i915_dsc_fec_support_show(struct seq_file *m, void *data)
 			   str_yes_no(drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)));
 		seq_printf(m, "Force_DSC_Enable: %s\n",
 			   str_yes_no(intel_dp->force_dsc_en));
+		seq_printf(m, "DSC_YCBCR420_Sink_Support: %s\n",
+			   str_yes_no(drm_dp_dsc_sink_supports_format(intel_dp->dsc_dpcd, DP_DSC_YCbCr420_Native)));
 		if (!intel_dp_is_edp(intel_dp))
 			seq_printf(m, "FEC_Sink_Support: %s\n",
 				   str_yes_no(drm_dp_sink_supports_fec(intel_dp->fec_capable)));
@@ -1893,6 +1895,85 @@ static const struct file_operations i915_dsc_bpc_fops = {
 	.write = i915_dsc_bpc_write
 };
 
+static int i915_dsc_ycbcr420_show(struct seq_file *m, void *data)
+{
+	struct drm_connector *connector = m->private;
+	struct drm_device *dev = connector->dev;
+	struct drm_crtc *crtc;
+	struct intel_dp *intel_dp;
+	struct intel_crtc_state *crtc_state;
+	struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
+	int ret;
+
+	if (!encoder)
+		return -ENODEV;
+
+	ret = drm_modeset_lock_single_interruptible(&dev->mode_config.connection_mutex);
+	if (ret)
+		return ret;
+
+	crtc = connector->state->crtc;
+	if (connector->status != connector_status_connected || !crtc) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	intel_dp = intel_attached_dp(to_intel_connector(connector));
+	crtc_state = to_intel_crtc_state(crtc->state);
+	seq_printf(m, "Force_DSC_YCBCR420_Enable: %s\n",
+		   str_yes_no(intel_dp->force_dsc_ycbcr420_en));
+
+out:	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+	return ret;
+}
+
+static ssize_t i915_dsc_ycbcr420_write(struct file *file,
+				       const char __user *ubuf,
+				       size_t len, loff_t *offp)
+{
+	struct drm_connector *connector =
+		((struct seq_file *)file->private_data)->private;
+	struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+	bool dsc_ycbcr420_enable = false;
+	int ret;
+
+	if (len == 0)
+		return 0;
+
+	drm_dbg(&i915->drm,
+		"Copied %zu bytes from user to force YCBCR420 for DSC\n", len);
+
+	ret = kstrtobool_from_user(ubuf, len, &dsc_ycbcr420_enable);
+	if (ret < 0)
+		return ret;
+
+	drm_dbg(&i915->drm, "Got %s for DSC YCBCR420 Enable\n",
+		(dsc_ycbcr420_enable) ? "true" : "false");
+	intel_dp->force_dsc_ycbcr420_en = dsc_ycbcr420_enable;
+
+	*offp += len;
+
+	return len;
+}
+
+static int i915_dsc_ycbcr420_open(struct inode *inode,
+				  struct file *file)
+{
+	return single_open(file, i915_dsc_ycbcr420_show, inode->i_private);
+}
+
+static const struct file_operations i915_dsc_ycbcr420_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_dsc_ycbcr420_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = i915_dsc_ycbcr420_write
+};
+
 /*
  * Returns the Current CRTC's bpc.
  * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
@@ -1964,6 +2045,9 @@ void intel_connector_debugfs_add(struct intel_connector *intel_connector)
 
 		debugfs_create_file("i915_dsc_bpc", 0644, root,
 				    connector, &i915_dsc_bpc_fops);
+
+		debugfs_create_file("i915_dsc_ycbcr420", 0644, root,
+				    connector, &i915_dsc_ycbcr420_fops);
 	}
 
 	if (connector->connector_type == DRM_MODE_CONNECTOR_DSI ||
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 7f18c052ec16..a8d6109bdc66 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1717,6 +1717,7 @@ struct intel_dp {
 
 	/* Display stream compression testing */
 	bool force_dsc_en;
+	bool force_dsc_ycbcr420_en;
 	int force_dsc_bpc;
 
 	bool hobl_failed;
-- 
2.25.1