drm/i915: constify hotplug function vtable.

Use a macro to avoid mistakes, this type of macro is only used
in a couple of places.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/af229c1e8ec894f177b344ab77b90e32c33428de.1632869550.git.jani.nikula@intel.com

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

@@ -215,8 +215,8 @@ intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 
 static void intel_hpd_irq_setup(struct drm_i915_private *i915)
 {
-	if (i915->display_irqs_enabled && i915->hotplug_funcs.hpd_irq_setup)
-		i915->hotplug_funcs.hpd_irq_setup(i915);
+	if (i915->display_irqs_enabled && i915->hotplug_funcs->hpd_irq_setup)
+		i915->hotplug_funcs->hpd_irq_setup(i915);
 }
 
 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)

drivers/gpu/drm/i915/i915_drv.h

@@ -988,7 +988,7 @@ struct drm_i915_private {
 	struct drm_i915_wm_disp_funcs wm_disp;
 
 	/* irq display functions */
-	struct intel_hotplug_funcs hotplug_funcs;
+	const struct intel_hotplug_funcs *hotplug_funcs;
 
 	/* fdi display functions */
 	const struct intel_fdi_funcs *fdi_funcs;

drivers/gpu/drm/i915/i915_irq.c

@@ -4345,6 +4345,20 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 	return ret;
 }
 
+#define HPD_FUNCS(platform)					 \
+static const struct intel_hotplug_funcs platform##_hpd_funcs = { \
+	.hpd_irq_setup = platform##_hpd_irq_setup,		 \
+}
+
+HPD_FUNCS(i915);
+HPD_FUNCS(dg1);
+HPD_FUNCS(gen11);
+HPD_FUNCS(bxt);
+HPD_FUNCS(icp);
+HPD_FUNCS(spt);
+HPD_FUNCS(ilk);
+#undef HPD_FUNCS
+
 /**
  * intel_irq_init - initializes irq support
  * @dev_priv: i915 device instance
@@ -4395,20 +4409,20 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 
 	if (HAS_GMCH(dev_priv)) {
 		if (I915_HAS_HOTPLUG(dev_priv))
-			dev_priv->hotplug_funcs.hpd_irq_setup = i915_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &i915_hpd_funcs;
 	} else {
 		if (HAS_PCH_DG1(dev_priv))
-			dev_priv->hotplug_funcs.hpd_irq_setup = dg1_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &dg1_hpd_funcs;
 		else if (DISPLAY_VER(dev_priv) >= 11)
-			dev_priv->hotplug_funcs.hpd_irq_setup = gen11_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &gen11_hpd_funcs;
 		else if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
-			dev_priv->hotplug_funcs.hpd_irq_setup = bxt_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &bxt_hpd_funcs;
 		else if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
-			dev_priv->hotplug_funcs.hpd_irq_setup = icp_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &icp_hpd_funcs;
 		else if (INTEL_PCH_TYPE(dev_priv) >= PCH_SPT)
-			dev_priv->hotplug_funcs.hpd_irq_setup = spt_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &spt_hpd_funcs;
 		else
-			dev_priv->hotplug_funcs.hpd_irq_setup = ilk_hpd_irq_setup;
+			dev_priv->hotplug_funcs = &ilk_hpd_funcs;
 	}
 }