[Intel-gfx] [v3 4/7] i915/dp/fec: Add can_fec to the crtc state.

[Anusha Srivatsa]

Add a crtc state for FEC. Currently, the state
is determined by platform, DP and DSC being
enabled. Moving forward we can use the state
to have error correction on other scenarios too
if needed.

Suggested-by: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Manasi Navare <manasi.d.navare at intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 22 ++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  3 +++
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index cfcef9e4b5d9..4776ce6f2174 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2045,6 +2045,23 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
 	return false;
 }
 
+static bool intel_dp_can_fec(struct intel_dp *intel_dp,
+			     struct intel_crtc_state *pipe_config)
+{
+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
+	if (INTEL_GEN(dev_priv) < 11 || intel_dp_is_edp(intel_dp))
+		return false;
+
+	/* On Gen 11, FEC is Supported Only for DP SST modes.
+	 * Let us start by enabling FEC for Compressed streams.
+	 */
+	if (pipe_config->dsc_params.compression_enable)
+		return true;
+	else
+		return false;
+
+}
 static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 					struct intel_crtc_state *pipe_config,
 					struct link_config_limits *limits)
@@ -2129,6 +2146,11 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 		      pipe_config->dsc_params.compressed_bpp,
 		      pipe_config->dsc_params.slice_count);
 
+	/* For DP 1.4, Enable DSC if FEC can be configured */
+	pipe_config->can_fec = intel_dp_can_fec(intel_dp, pipe_config);
+	if (!pipe_config->can_fec)
+		return false;
+
 	return true;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 9a94c6544bf5..9dac242ead12 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -940,6 +940,9 @@ struct intel_crtc_state {
 		u8 slice_count;
 	} dsc_params;
 	struct drm_dsc_config dp_dsc_cfg;
+
+	/* Forward Error correction State */
+	bool can_fec;
 };
 
 struct intel_crtc {
-- 
2.17.1