[PATCH 3/3] display/alpm: Calculate alpm latency

[Mitul Golani]

Calculate latency added by enabling the feature.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
---
 drivers/gpu/drm/i915/display/intel_alpm.c | 21 +++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_alpm.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
index 55f3ae1e68c9..6edb83ca215c 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.c
+++ b/drivers/gpu/drm/i915/display/intel_alpm.c
@@ -415,3 +415,24 @@ void intel_alpm_lobf_debugfs_add(struct intel_connector *connector)
 	debugfs_create_file("i915_edp_lobf_info", 0444, root,
 			    connector, &i915_edp_lobf_info_fops);
 }
+
+int calc_alpm_latency(struct intel_crtc_state *crtc_state)
+{
+	int val, enabled, linetime, aux_less_wake_lines;
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+
+	if (!crtc_state->has_lobf)
+		return 0;
+
+	linetime = DIV_ROUND_UP(crtc_state->hw.adjusted_mode.htotal * 1000,
+				intel_crtc_dotclock(crtc_state));
+
+	val = intel_de_read(i915,
+			    ALPM_CTL(i915, crtc_state->cpu_transcoder));
+	enabled = val & ALPM_CTL_ALPM_ENABLE;
+	aux_less_wake_lines = ALPM_CTL_AUX_LESS_WAKE_TIME_MASK & val;
+
+	return intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
+					enabled * aux_less_wake_lines * linetime);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h b/drivers/gpu/drm/i915/display/intel_alpm.h
index 8c409b10dce6..11074dc41796 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.h
+++ b/drivers/gpu/drm/i915/display/intel_alpm.h
@@ -24,4 +24,5 @@ void intel_alpm_configure(struct intel_dp *intel_dp,
 void intel_alpm_lobf_debugfs_add(struct intel_connector *connector);
 bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp);
 bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp);
+int calc_alpm_latency(struct intel_crtc_state *crtc_state);
 #endif
-- 
2.46.0