[PATCH 05/15] drm/i915/display: Extract helpers to set dsc/scaler prefill latencies

[Ankit Nautiyal]

Currently dsc/scaler prefill latencies are handled during watermark
calculations. With the optimized guardband, we need to compute the
latencies to find the minimum guardband that works for most cases.
Extract the helpers to compute these latencies, so that they can be used
while computing vrr guardband.

While at it, put declarations in reverse xmas tree order for better
redability.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 34 +++++++++++++++
 drivers/gpu/drm/i915/display/intel_display.h |  8 ++++
 drivers/gpu/drm/i915/display/skl_watermark.c | 46 +++++++++-----------
 3 files changed, 63 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 7035c1fc9033..91abfaad86b8 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -8322,3 +8322,37 @@ bool intel_scanout_needs_vtd_wa(struct intel_display *display)
 
 	return IS_DISPLAY_VER(display, 6, 11) && i915_vtd_active(i915);
 }
+
+int intel_display_scaler_prefill_latency(int num_scaler_users, u64 hscale, u64 vscale,
+					 int chroma_downscaling_factor,
+					 int cdclk_prefill_adjustment,
+					 int linetime)
+{
+	int scaler_prefill_latency;
+
+	scaler_prefill_latency = 4 * linetime;
+	if (num_scaler_users > 1)
+		scaler_prefill_latency += DIV_ROUND_UP_ULL((4 * linetime * hscale * vscale *
+							    chroma_downscaling_factor), 1000000);
+
+	scaler_prefill_latency *= cdclk_prefill_adjustment;
+
+	return scaler_prefill_latency;
+}
+
+int intel_display_dsc_prefill_latency(int num_scaler_users, u64 *hscale, u64 *vscale,
+				      int chroma_downscaling_factor,
+				      int cdclk_prefill_adjustment,
+				      int linetime)
+{
+	int dsc_prefill_latency;
+
+	dsc_prefill_latency = DIV_ROUND_UP(15 * linetime * chroma_downscaling_factor, 10);
+
+	for (int i = 0; i < num_scaler_users; i++)
+		dsc_prefill_latency = DIV_ROUND_UP_ULL(dsc_prefill_latency * hscale[i] * vscale[i],
+						       1000000);
+	dsc_prefill_latency *= cdclk_prefill_adjustment;
+
+	return dsc_prefill_latency;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index 37e2ab301a80..8d094b0a8c6b 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -559,5 +559,13 @@ bool assert_port_valid(struct intel_display *display, enum port port);
 
 bool intel_scanout_needs_vtd_wa(struct intel_display *display);
 int intel_crtc_num_joined_pipes(const struct intel_crtc_state *crtc_state);
+int intel_display_scaler_prefill_latency(int num_scaler_users, u64 hscale, u64 vscale,
+					 int chroma_downscaling_factor,
+					 int cdclk_prefill_adjustment,
+					 int linetime);
+int intel_display_dsc_prefill_latency(int num_scaler_users, u64 *hscale, u64 *vscale,
+				      int chroma_downscaling_factor,
+				      int cdclk_prefill_adjustment,
+				      int linetime);
 
 #endif
diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c
index 6c7e9e7d7b8e..76278153fc0b 100644
--- a/drivers/gpu/drm/i915/display/skl_watermark.c
+++ b/drivers/gpu/drm/i915/display/skl_watermark.c
@@ -2180,11 +2180,12 @@ cdclk_prefill_adjustment(const struct intel_crtc_state *crtc_state)
 static int
 dsc_prefill_latency(const struct intel_crtc_state *crtc_state, int linetime)
 {
+	const struct intel_crtc_scaler_state *scaler_state = &crtc_state->scaler_state;
+	int chroma_downscaling_factor = skl_scaler_chroma_downscale_factor(crtc_state);
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
-	const struct intel_crtc_scaler_state *scaler_state =
-					&crtc_state->scaler_state;
 	int num_scaler_users = hweight32(scaler_state->scaler_users);
-	int chroma_downscaling_factor = skl_scaler_chroma_downscale_factor(crtc_state);
+	u64 hscale_k[ARRAY_SIZE(scaler_state->scalers)];
+	u64 vscale_k[ARRAY_SIZE(scaler_state->scalers)];
 	u32 dsc_prefill_latency = 0;
 
 	if (!crtc_state->dsc.compression_enable ||
@@ -2193,18 +2194,16 @@ dsc_prefill_latency(const struct intel_crtc_state *crtc_state, int linetime)
 	    num_scaler_users > ARRAY_SIZE(scaler_state->scalers))
 		return dsc_prefill_latency;
 
-	dsc_prefill_latency = DIV_ROUND_UP(15 * linetime * chroma_downscaling_factor, 10);
-
 	for (int i = 0; i < num_scaler_users; i++) {
-		u64 hscale_k, vscale_k;
-
-		hscale_k = max(1000, mul_u32_u32(scaler_state->scalers[i].hscale, 1000) >> 16);
-		vscale_k = max(1000, mul_u32_u32(scaler_state->scalers[i].vscale, 1000) >> 16);
-		dsc_prefill_latency = DIV_ROUND_UP_ULL(dsc_prefill_latency * hscale_k * vscale_k,
-						       1000000);
+		hscale_k[i] = max(1000, mul_u32_u32(scaler_state->scalers[i].hscale, 1000) >> 16);
+		vscale_k[i] = max(1000, mul_u32_u32(scaler_state->scalers[i].vscale, 1000) >> 16);
 	}
 
-	dsc_prefill_latency *= cdclk_prefill_adjustment(crtc_state);
+	dsc_prefill_latency =
+		intel_display_dsc_prefill_latency(num_scaler_users, hscale_k, vscale_k,
+						  chroma_downscaling_factor,
+						  cdclk_prefill_adjustment(crtc_state),
+						  linetime);
 
 	return dsc_prefill_latency;
 }
@@ -2212,28 +2211,25 @@ dsc_prefill_latency(const struct intel_crtc_state *crtc_state, int linetime)
 static int
 scaler_prefill_latency(const struct intel_crtc_state *crtc_state, int linetime)
 {
-	const struct intel_crtc_scaler_state *scaler_state =
-					&crtc_state->scaler_state;
+	const struct intel_crtc_scaler_state *scaler_state = &crtc_state->scaler_state;
+	int chroma_downscaling_factor = skl_scaler_chroma_downscale_factor(crtc_state);
 	int num_scaler_users = hweight32(scaler_state->scaler_users);
+	u64 hscale_k = 1000, vscale_k = 1000;
 	int scaler_prefill_latency = 0;
 
 	if (!num_scaler_users)
 		return scaler_prefill_latency;
 
-	scaler_prefill_latency = 4 * linetime;
-
 	if (num_scaler_users > 1) {
-		u64 hscale_k = max(1000, mul_u32_u32(scaler_state->scalers[0].hscale, 1000) >> 16);
-		u64 vscale_k = max(1000, mul_u32_u32(scaler_state->scalers[0].vscale, 1000) >> 16);
-		int chroma_downscaling_factor = skl_scaler_chroma_downscale_factor(crtc_state);
-		int latency;
-
-		latency = DIV_ROUND_UP_ULL((4 * linetime * hscale_k * vscale_k *
-					    chroma_downscaling_factor), 1000000);
-		scaler_prefill_latency += latency;
+		hscale_k = max(1000, mul_u32_u32(scaler_state->scalers[0].hscale, 1000) >> 16);
+		vscale_k = max(1000, mul_u32_u32(scaler_state->scalers[0].vscale, 1000) >> 16);
 	}
 
-	scaler_prefill_latency *= cdclk_prefill_adjustment(crtc_state);
+	scaler_prefill_latency =
+		intel_display_scaler_prefill_latency(num_scaler_users, hscale_k, vscale_k,
+						     chroma_downscaling_factor,
+						     cdclk_prefill_adjustment(crtc_state),
+						     linetime);
 
 	return scaler_prefill_latency;
 }
-- 
2.45.2