drm/i915: Introduce for_each_shared_dpll()

No one really cares how we store the shared_dplls. Currently
it happens to be an array, but we could change that to a more
flexible scheme at some point. Hide the implementation details
behind an iterator macro.

The slight downside is the pll variable moving out of the
loop scope, but maybe someday soon we'll start to convert
everything over to having declarations within for-statements...
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231003200620.11633-4-ville.syrjala@linux.intel.com

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

@@ -645,6 +645,7 @@ static int i915_display_info(struct seq_file *m, void *unused)
 static int i915_shared_dplls_info(struct seq_file *m, void *unused)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
+	struct intel_shared_dpll *pll;
 	int i;
 
 	drm_modeset_lock_all(&dev_priv->drm);
@@ -653,9 +654,7 @@ static int i915_shared_dplls_info(struct seq_file *m, void *unused)
 		   dev_priv->display.dpll.ref_clks.nssc,
 		   dev_priv->display.dpll.ref_clks.ssc);
 
-	for (i = 0; i < dev_priv->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &dev_priv->display.dpll.shared_dplls[i];
-
+	for_each_shared_dpll(dev_priv, pll, i) {
 		seq_printf(m, "DPLL%i: %s, id: %i\n", pll->index,
 			   pll->info->name, pll->info->id);
 		seq_printf(m, " pipe_mask: 0x%x, active: 0x%x, on: %s\n",

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

@@ -115,14 +115,12 @@ static void
 intel_atomic_duplicate_dpll_state(struct drm_i915_private *dev_priv,
 				  struct intel_shared_dpll_state *shared_dpll)
 {
+	struct intel_shared_dpll *pll;
 	int i;
 
 	/* Copy shared dpll state */
-	for (i = 0; i < dev_priv->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &dev_priv->display.dpll.shared_dplls[i];
-
+	for_each_shared_dpll(dev_priv, pll, i)
 		shared_dpll[pll->index] = pll->state;
-	}
 }
 
 static struct intel_shared_dpll_state *
@@ -154,11 +152,10 @@ struct intel_shared_dpll *
 intel_get_shared_dpll_by_id(struct drm_i915_private *dev_priv,
 			    enum intel_dpll_id id)
 {
+	struct intel_shared_dpll *pll;
 	int i;
 
-	for (i = 0; i < dev_priv->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &dev_priv->display.dpll.shared_dplls[i];
-
+	for_each_shared_dpll(dev_priv, pll, i) {
 		if (pll->info->id == id)
 			return pll;
 	}
@@ -317,12 +314,11 @@ void intel_disable_shared_dpll(const struct intel_crtc_state *crtc_state)
 static unsigned long
 intel_dpll_mask_all(struct drm_i915_private *i915)
 {
+	struct intel_shared_dpll *pll;
 	unsigned long dpll_mask = 0;
 	int i;
 
-	for (i = 0; i < i915->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &i915->display.dpll.shared_dplls[i];
-
+	for_each_shared_dpll(i915, pll, i) {
 		drm_WARN_ON(&i915->drm, dpll_mask & BIT(pll->info->id));
 
 		dpll_mask |= BIT(pll->info->id);
@@ -489,16 +485,14 @@ void intel_shared_dpll_swap_state(struct intel_atomic_state *state)
 {
 	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
 	struct intel_shared_dpll_state *shared_dpll = state->shared_dpll;
+	struct intel_shared_dpll *pll;
 	int i;
 
 	if (!state->dpll_set)
 		return;
 
-	for (i = 0; i < dev_priv->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &dev_priv->display.dpll.shared_dplls[i];
-
+	for_each_shared_dpll(dev_priv, pll, i)
 		swap(pll->state, shared_dpll[pll->index]);
-	}
 }
 
 static bool ibx_pch_dpll_get_hw_state(struct drm_i915_private *dev_priv,
@@ -4401,10 +4395,11 @@ void intel_dpll_update_ref_clks(struct drm_i915_private *i915)
 
 void intel_dpll_readout_hw_state(struct drm_i915_private *i915)
 {
+	struct intel_shared_dpll *pll;
 	int i;
 
-	for (i = 0; i < i915->display.dpll.num_shared_dpll; i++)
-		readout_dpll_hw_state(i915, &i915->display.dpll.shared_dplls[i]);
+	for_each_shared_dpll(i915, pll, i)
+		readout_dpll_hw_state(i915, pll);
 }
 
 static void sanitize_dpll_state(struct drm_i915_private *i915,
@@ -4428,10 +4423,11 @@ static void sanitize_dpll_state(struct drm_i915_private *i915,
 
 void intel_dpll_sanitize_state(struct drm_i915_private *i915)
 {
+	struct intel_shared_dpll *pll;
 	int i;
 
-	for (i = 0; i < i915->display.dpll.num_shared_dpll; i++)
-		sanitize_dpll_state(i915, &i915->display.dpll.shared_dplls[i]);
+	for_each_shared_dpll(i915, pll, i)
+		sanitize_dpll_state(i915, pll);
 }
 
 /**
@@ -4542,9 +4538,9 @@ void intel_shared_dpll_state_verify(struct intel_crtc *crtc,
 
 void intel_shared_dpll_verify_disabled(struct drm_i915_private *i915)
 {
+	struct intel_shared_dpll *pll;
 	int i;
 
-	for (i = 0; i < i915->display.dpll.num_shared_dpll; i++)
-		verify_single_dpll_state(i915, &i915->display.dpll.shared_dplls[i],
-					 NULL, NULL);
+	for_each_shared_dpll(i915, pll, i)
+		verify_single_dpll_state(i915, pll, NULL, NULL);
 }

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

@@ -29,6 +29,10 @@
 
 #include "intel_wakeref.h"
 
+#define for_each_shared_dpll(__i915, __pll, __i) \
+	for ((__i) = 0; (__i) < (__i915)->display.dpll.num_shared_dpll && \
+		     ((__pll) = &(__i915)->display.dpll.shared_dplls[(__i)]) ; (__i)++)
+
 enum tc_port;
 struct drm_i915_private;
 struct intel_atomic_state;

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

@@ -492,6 +492,7 @@ static void lpt_init_pch_refclk(struct drm_i915_private *dev_priv)
 static void ilk_init_pch_refclk(struct drm_i915_private *dev_priv)
 {
 	struct intel_encoder *encoder;
+	struct intel_shared_dpll *pll;
 	int i;
 	u32 val, final;
 	bool has_lvds = false;
@@ -527,8 +528,7 @@ static void ilk_init_pch_refclk(struct drm_i915_private *dev_priv)
 	}
 
 	/* Check if any DPLLs are using the SSC source */
-	for (i = 0; i < dev_priv->display.dpll.num_shared_dpll; i++) {
-		struct intel_shared_dpll *pll = &dev_priv->display.dpll.shared_dplls[i];
+	for_each_shared_dpll(dev_priv, pll, i) {
 		u32 temp;
 
 		temp = intel_de_read(dev_priv, PCH_DPLL(pll->info->id));