drm/i915/alpm: Add compute config for lobf

Link Off Between Active Frames, is a new feature for eDP
that allows the panel to go to lower power state after
transmission of data. This is a feature on top of ALPM, AS SDP.
Add compute config during atomic-check phase.

v1: RFC version.
v2: Add separate flag for auxless-alpm. [Jani]
v3:
- intel_dp->lobf_supported replaced with crtc_state->has_lobf. [Jouni]
- Add DISPLAY_VER() check. [Jouni]
- Modify function name of get_aux_less_status. [Jani]
v4: Add enum alpm_mode to hold the aux-wake/less capability.
v5: Add alpm_dpcd to intel_dp and use aux_wake_supported()/
aux_less_wake_supported() instead of enum alpm_mode. [Jouni]

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240529200742.1694401-5-animesh.manna@intel.com

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
index 7307e02277d6..3ac5986b4ad9 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.c
+++ b/drivers/gpu/drm/i915/display/intel_alpm.c
@@ -11,6 +11,26 @@
 #include "intel_dp_aux.h"
 #include "intel_psr_regs.h"
 
+static bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp)
+{
+	return intel_dp->alpm_dpcd & DP_ALPM_CAP;
+}
+
+static bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp)
+{
+	return intel_dp->alpm_dpcd & DP_ALPM_AUX_LESS_CAP;
+}
+
+void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
+{
+	u8 dpcd;
+
+	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP, &dpcd) < 0)
+		return;
+
+	intel_dp->alpm_dpcd = dpcd;
+}
+
 /*
  * See Bspec: 71632 for the table
  *
@@ -243,6 +263,47 @@ bool intel_alpm_compute_params(struct intel_dp *intel_dp,
 	return true;
 }
 
+void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,
+				    struct intel_crtc_state *crtc_state,
+				    struct drm_connector_state *conn_state)
+{
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
+	int waketime_in_lines, first_sdp_position;
+	int context_latency, guardband;
+
+	if (!intel_dp_is_edp(intel_dp))
+		return;
+
+	if (DISPLAY_VER(i915) < 20)
+		return;
+
+	if (!intel_dp_as_sdp_supported(intel_dp))
+		return;
+
+	if (crtc_state->has_psr)
+		return;
+
+	if (!(intel_alpm_aux_wake_supported(intel_dp) ||
+	      intel_alpm_aux_less_wake_supported(intel_dp)))
+		return;
+
+	if (!intel_alpm_compute_params(intel_dp, crtc_state))
+		return;
+
+	context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
+	guardband = adjusted_mode->crtc_vtotal -
+		    adjusted_mode->crtc_vdisplay - context_latency;
+	first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start;
+	if (intel_alpm_aux_less_wake_supported(intel_dp))
+		waketime_in_lines = intel_dp->alpm_parameters.io_wake_lines;
+	else
+		waketime_in_lines = intel_dp->alpm_parameters.fast_wake_lines;
+
+	crtc_state->has_lobf = (context_latency + guardband) >
+		(first_sdp_position + waketime_in_lines);
+}
+
 static void lnl_alpm_configure(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);