drm/i915/lnl: Program PKGC_LATENCY register

If fixed refresh rate program the PKGC_LATENCY register
with the highest latency from level 1 and above LP registers
and program ADDED_WAKE_TIME = DSB execution time.
else program PKGC_LATENCY with all 1's and ADDED_WAKE_TIME as 0.
This is used to improve package C residency by sending the highest
latency tolerance requirement (LTR) when the planes are done with the
frame until the next frame programming window (set context latency,
window 2) starts.
Bspec: 68986

--v2
-Fix indentation [Chaitanya]

--v3
-Take into account if fixed refrersh rate or not [Vinod]
-Added wake time dependengt on DSB execution time [Vinod]
-Use REG_FIELD_PREP [Jani]
-Call program_pkgc_latency from appropriate place [Jani]
-no need for the ~0 while setting max latency [Jani]
-change commit message to add the new changes made in.

--v4
-Remove extra blank line [Vinod]
-move the vrr.enable check to previous loop [Vinod]
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240219063638.1467114-1-suraj.kandpal@intel.com

drivers/gpu/drm/i915/display/intel_dsb.c

@@ -325,7 +325,7 @@ static int intel_dsb_dewake_scanline(const struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
 	const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
-	unsigned int latency = skl_watermark_max_latency(i915);
+	unsigned int latency = skl_watermark_max_latency(i915, 0);
 	int vblank_start;
 
 	if (crtc_state->vrr.enable) {

drivers/gpu/drm/i915/display/skl_watermark.c

@@ -23,6 +23,12 @@
 #include "skl_watermark.h"
 #include "skl_watermark_regs.h"
 
+/*It is expected that DSB can do posted writes to every register in
+ * the pipe and planes within 100us. For flip queue use case, the
+ * recommended DSB execution time is 100us + one SAGV block time.
+ */
+#define DSB_EXE_TIME 100
+
 static void skl_sagv_disable(struct drm_i915_private *i915);
 
 /* Stores plane specific WM parameters */
@@ -2904,12 +2910,51 @@ static int skl_wm_add_affected_planes(struct intel_atomic_state *state,
 	return 0;
 }
 
+/*
+ * If Fixed Refresh Rate:
+ * Program DEEP PKG_C_LATENCY Pkg C with highest valid latency from
+ * watermark level1 and up and above. If watermark level 1 is
+ * invalid program it with all 1's.
+ * Program PKG_C_LATENCY Added Wake Time = DSB execution time
+ * If Variable Refresh Rate:
+ * Program DEEP PKG_C_LATENCY Pkg C with all 1's.
+ * Program PKG_C_LATENCY Added Wake Time = 0
+ */
+static void
+skl_program_dpkgc_latency(struct drm_i915_private *i915, bool vrr_enabled)
+{
+	u32 max_latency = 0;
+	u32 clear = 0, val = 0;
+	u32 added_wake_time = 0;
+
+	if (DISPLAY_VER(i915) < 20)
+		return;
+
+	if (vrr_enabled) {
+		max_latency = LNL_PKG_C_LATENCY_MASK;
+		added_wake_time = 0;
+	} else {
+		max_latency = skl_watermark_max_latency(i915, 1);
+		if (max_latency == 0)
+			max_latency = LNL_PKG_C_LATENCY_MASK;
+		added_wake_time = DSB_EXE_TIME +
+			i915->display.sagv.block_time_us;
+	}
+
+	clear |= LNL_ADDED_WAKE_TIME_MASK | LNL_PKG_C_LATENCY_MASK;
+	val |= REG_FIELD_PREP(LNL_PKG_C_LATENCY_MASK, max_latency);
+	val |= REG_FIELD_PREP(LNL_ADDED_WAKE_TIME_MASK, added_wake_time);
+
+	intel_uncore_rmw(&i915->uncore, LNL_PKG_C_LATENCY, clear, val);
+}
+
 static int
 skl_compute_wm(struct intel_atomic_state *state)
 {
 	struct intel_crtc *crtc;
 	struct intel_crtc_state __maybe_unused *new_crtc_state;
 	int ret, i;
+	bool vrr_enabled = false;
 
 	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
 		ret = skl_build_pipe_wm(state, crtc);
@@ -2934,8 +2979,13 @@ skl_compute_wm(struct intel_atomic_state *state)
 		ret = skl_wm_add_affected_planes(state, crtc);
 		if (ret)
 			return ret;
+
+		if (new_crtc_state->vrr.enable)
+			vrr_enabled = true;
 	}
 
+	skl_program_dpkgc_latency(to_i915(state->base.dev), vrr_enabled);
+
 	skl_print_wm_changes(state);
 
 	return 0;
@@ -3731,11 +3781,11 @@ void skl_watermark_debugfs_register(struct drm_i915_private *i915)
 				    &intel_sagv_status_fops);
 }
 
-unsigned int skl_watermark_max_latency(struct drm_i915_private *i915)
+unsigned int skl_watermark_max_latency(struct drm_i915_private *i915, int initial_wm_level)
 {
 	int level;
 
-	for (level = i915->display.wm.num_levels - 1; level >= 0; level--) {
+	for (level = i915->display.wm.num_levels - 1; level >= initial_wm_level; level--) {
 		unsigned int latency = skl_wm_latency(i915, level, NULL);
 
 		if (latency)

drivers/gpu/drm/i915/display/skl_watermark.h

@@ -46,8 +46,8 @@ void skl_watermark_ipc_update(struct drm_i915_private *i915);
 bool skl_watermark_ipc_enabled(struct drm_i915_private *i915);
 void skl_watermark_debugfs_register(struct drm_i915_private *i915);
 
-unsigned int skl_watermark_max_latency(struct drm_i915_private *i915);
-
+unsigned int skl_watermark_max_latency(struct drm_i915_private *i915,
+				       int initial_wm_level);
 void skl_wm_init(struct drm_i915_private *i915);
 
 struct intel_dbuf_state {