If FEC is supported, the corresponding DP_TP_CTL register bits have to be configured.

The driver has to program the FEC_ENABLE in DP_TP_CTL[30] register and wait till FEC_STATUS in DP_TP_CTL[28] is 1. Also add the warn message to make sure that the control register is already active while enabling FEC.

v2: - Change commit message. Configure fec state after link training (Manasi, Gaurav) - Remove redundent checks (Manasi) - Remove the registers that get added automagically (Anusha)

v3: s/intel_dp_set_fec_state()/intel_dp_enable_fec_state() (Gaurav)

v4: rebased.

v5: - Move the code to the proper spot, according to spec.(Ville) - Use fec state as a check too.

v6: Pass intel_encoder, instead of intel_dp. (Ville)

Cc: dri-devel@lists.freedesktop.org Cc: Gaurav K Singh gaurav.k.singh@intel.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Ville Syrjala ville.syrjala@linux.intel.com Cc: Manasi Navare manasi.d.navare@intel.com Signed-off-by: Anusha Srivatsa anusha.srivatsa@intel.com --- drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_ddi.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index e85f53cb9cdd..8b1753939299 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -9134,6 +9134,7 @@ enum skl_power_gate { #define _DP_TP_CTL_B 0x64140 #define DP_TP_CTL(port) _MMIO_PORT(port, _DP_TP_CTL_A, _DP_TP_CTL_B) #define DP_TP_CTL_ENABLE (1 << 31) +#define DP_TP_CTL_FEC_ENABLE (1 << 30) #define DP_TP_CTL_MODE_SST (0 << 27) #define DP_TP_CTL_MODE_MST (1 << 27) #define DP_TP_CTL_FORCE_ACT (1 << 25) @@ -9152,6 +9153,7 @@ enum skl_power_gate { #define _DP_TP_STATUS_A 0x64044 #define _DP_TP_STATUS_B 0x64144 #define DP_TP_STATUS(port) _MMIO_PORT(port, _DP_TP_STATUS_A, _DP_TP_STATUS_B) +#define DP_TP_STATUS_FEC_ENABLE_LIVE (1 << 28) #define DP_TP_STATUS_IDLE_DONE (1 << 25) #define DP_TP_STATUS_ACT_SENT (1 << 24) #define DP_TP_STATUS_MODE_STATUS_MST (1 << 23) diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 05b6ffeb13be..807edba4cd6f 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -2903,6 +2903,28 @@ static void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp, DRM_DEBUG_KMS("Failed to get FEC enabled in sink\n"); }

+static void intel_ddi_enable_fec(struct intel_encoder *encoder, + const struct intel_crtc_state *crtc_state) +{ + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); + enum port port = encoder->port; + u32 val; + + /* FEC support exists for DP 1.4 only */ + if (!crtc_state->fec_enable) + return; + + val = I915_READ(DP_TP_CTL(port)); + val |= DP_TP_CTL_FEC_ENABLE; + I915_WRITE(DP_TP_CTL(port), val); + + if (intel_wait_for_register(dev_priv, DP_TP_STATUS(port), + DP_TP_STATUS_FEC_ENABLE_LIVE, + DP_TP_STATUS_FEC_ENABLE_LIVE, + 1)) + DRM_ERROR("Timed out waiting for FEC Enable Status\n"); +} + static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder, const struct intel_crtc_state *crtc_state, const struct drm_connector_state *conn_state) @@ -2951,6 +2973,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder, if (port != PORT_A || INTEL_GEN(dev_priv) >= 9) intel_dp_stop_link_train(intel_dp);

+ intel_ddi_enable_fec(encoder, crtc_state); + icl_enable_phy_clock_gating(dig_port);

if (!is_mst)