drm/i915: Add crtc .crtc_get_shared_dpll()

Start splitting the .compute_crtc_clock() into two parts; one
part does the computation, the second part does the shared dpll
assignment. I want to move the actual computation part much earlier
into the compute_config() phase.

v2: dg2_crtc_get_shared_dpll() not needed (Jani)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220325123205.22140-10-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -4908,6 +4908,10 @@ static int intel_crtc_atomic_check(struct intel_atomic_state *state,
 		ret = intel_dpll_crtc_compute_clock(state, crtc);
 		if (ret)
 			return ret;
+
+		ret = intel_dpll_crtc_get_shared_dpll(state, crtc);
+		if (ret)
+			return ret;
 	}
 
 	/*

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

@@ -20,6 +20,8 @@
 struct intel_dpll_funcs {
 	int (*crtc_compute_clock)(struct intel_atomic_state *state,
 				  struct intel_crtc *crtc);
+	int (*crtc_get_shared_dpll)(struct intel_atomic_state *state,
+				    struct intel_crtc *crtc);
 };
 
 struct intel_limit {
@@ -930,6 +932,12 @@ static void i8xx_compute_dpll(struct intel_crtc_state *crtc_state,
 
 static int hsw_crtc_compute_clock(struct intel_atomic_state *state,
 				  struct intel_crtc *crtc)
+{
+	return 0;
+}
+
+static int hsw_crtc_get_shared_dpll(struct intel_atomic_state *state,
+				    struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
 	struct intel_crtc_state *crtc_state =
@@ -1087,7 +1095,6 @@ static int ilk_crtc_compute_clock(struct intel_atomic_state *state,
 		intel_atomic_get_new_crtc_state(state, crtc);
 	const struct intel_limit *limit;
 	int refclk = 120000;
-	int ret;
 
 	/* CPU eDP is the only output that doesn't need a PCH PLL of its own. */
 	if (!crtc_state->has_pch_encoder)
@@ -1127,6 +1134,21 @@ static int ilk_crtc_compute_clock(struct intel_atomic_state *state,
 	ilk_compute_dpll(crtc_state, &crtc_state->dpll,
 			 &crtc_state->dpll);
 
+	return 0;
+}
+
+static int ilk_crtc_get_shared_dpll(struct intel_atomic_state *state,
+				    struct intel_crtc *crtc)
+{
+	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+	struct intel_crtc_state *crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+	int ret;
+
+	/* CPU eDP is the only output that doesn't need a PCH PLL of its own. */
+	if (!crtc_state->has_pch_encoder)
+		return 0;
+
 	ret = intel_reserve_shared_dplls(state, crtc, NULL);
 	if (ret) {
 		drm_dbg_kms(&dev_priv->drm,
@@ -1376,10 +1398,12 @@ static const struct intel_dpll_funcs dg2_dpll_funcs = {
 
 static const struct intel_dpll_funcs hsw_dpll_funcs = {
 	.crtc_compute_clock = hsw_crtc_compute_clock,
+	.crtc_get_shared_dpll = hsw_crtc_get_shared_dpll,
 };
 
 static const struct intel_dpll_funcs ilk_dpll_funcs = {
 	.crtc_compute_clock = ilk_crtc_compute_clock,
+	.crtc_get_shared_dpll = ilk_crtc_get_shared_dpll,
 };
 
 static const struct intel_dpll_funcs chv_dpll_funcs = {
@@ -1427,6 +1451,27 @@ int intel_dpll_crtc_compute_clock(struct intel_atomic_state *state,
 	return i915->dpll_funcs->crtc_compute_clock(state, crtc);
 }
 
+int intel_dpll_crtc_get_shared_dpll(struct intel_atomic_state *state,
+				    struct intel_crtc *crtc)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+	struct intel_crtc_state *crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+
+	drm_WARN_ON(&i915->drm, !intel_crtc_needs_modeset(crtc_state));
+
+	if (drm_WARN_ON(&i915->drm, crtc_state->shared_dpll))
+		return 0;
+
+	if (!crtc_state->hw.enable)
+		return 0;
+
+	if (!i915->dpll_funcs->crtc_get_shared_dpll)
+		return 0;
+
+	return i915->dpll_funcs->crtc_get_shared_dpll(state, crtc);
+}
+
 void
 intel_dpll_init_clock_hook(struct drm_i915_private *dev_priv)
 {

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

@@ -18,6 +18,8 @@ enum pipe;
 void intel_dpll_init_clock_hook(struct drm_i915_private *dev_priv);
 int intel_dpll_crtc_compute_clock(struct intel_atomic_state *state,
 				  struct intel_crtc *crtc);
+int intel_dpll_crtc_get_shared_dpll(struct intel_atomic_state *state,
+				    struct intel_crtc *crtc);
 int vlv_calc_dpll_params(int refclk, struct dpll *clock);
 int pnv_calc_dpll_params(int refclk, struct dpll *clock);
 int i9xx_calc_dpll_params(int refclk, struct dpll *clock);