drm/i915/opregion: abstract getting the opregion VBT

Add a function to get the opregion VBT instead of accessing the opregion
structures directly.

Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/8205b8fa724f98bbf1f76c59e661909d874e843e.1704992868.git.jani.nikula@intel.com

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

@@ -3073,7 +3073,7 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *i915)
  */
 void intel_bios_init(struct drm_i915_private *i915)
 {
-	const struct vbt_header *vbt = i915->display.opregion.vbt;
+	const struct vbt_header *vbt;
 	struct vbt_header *oprom_vbt = NULL;
 	const struct bdb_header *bdb;
 
@@ -3088,6 +3088,8 @@ void intel_bios_init(struct drm_i915_private *i915)
 
 	init_vbt_defaults(i915);
 
+	vbt = intel_opregion_get_vbt(i915, NULL);
+
 	/*
 	 * If the OpRegion does not have VBT, look in SPI flash through MMIO or
 	 * PCI mapping
@@ -3305,7 +3307,7 @@ bool intel_bios_is_lvds_present(struct drm_i915_private *i915, u8 *i2c_pin)
 		 * additional data.  Trust that if the VBT was written into
 		 * the OpRegion then they have validated the LVDS's existence.
 		 */
-		if (i915->display.opregion.vbt)
+		if (intel_opregion_get_vbt(i915, NULL))
 			return true;
 	}
 
@@ -3660,14 +3662,16 @@ void intel_bios_for_each_encoder(struct drm_i915_private *i915,
 static int intel_bios_vbt_show(struct seq_file *m, void *unused)
 {
 	struct drm_i915_private *i915 = m->private;
-	struct intel_opregion *opregion = &i915->display.opregion;
+	const void *vbt;
+	size_t vbt_size;
 
 	/*
 	 * FIXME: VBT might originate from other places than opregion, and then
 	 * this would be incorrect.
 	 */
-	if (opregion->vbt)
-		seq_write(m, opregion->vbt, opregion->vbt_size);
+	vbt = intel_opregion_get_vbt(i915, &vbt_size);
+	if (vbt)
+		seq_write(m, vbt, vbt_size);
 
 	return 0;
 }

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

@@ -1132,6 +1132,19 @@ const struct drm_edid *intel_opregion_get_edid(struct intel_connector *intel_con
 	return drm_edid;
 }
 
+const void *intel_opregion_get_vbt(struct drm_i915_private *i915, size_t *size)
+{
+	struct intel_opregion *opregion = &i915->display.opregion;
+
+	if (!opregion->vbt)
+		return NULL;
+
+	if (size)
+		*size = opregion->vbt_size;
+
+	return opregion->vbt;
+}
+
 bool intel_opregion_headless_sku(struct drm_i915_private *i915)
 {
 	struct intel_opregion *opregion = &i915->display.opregion;

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

@@ -77,6 +77,8 @@ int intel_opregion_notify_adapter(struct drm_i915_private *dev_priv,
 int intel_opregion_get_panel_type(struct drm_i915_private *dev_priv);
 const struct drm_edid *intel_opregion_get_edid(struct intel_connector *connector);
 
+const void *intel_opregion_get_vbt(struct drm_i915_private *i915, size_t *size);
+
 bool intel_opregion_headless_sku(struct drm_i915_private *i915);
 
 void intel_opregion_debugfs_register(struct drm_i915_private *i915);
@@ -136,6 +138,12 @@ intel_opregion_get_edid(struct intel_connector *connector)
 	return NULL;
 }
 
+static inline const void *
+intel_opregion_get_vbt(struct drm_i915_private *i915, size_t *size)
+{
+	return NULL;
+}
+
 static inline bool intel_opregion_headless_sku(struct drm_i915_private *i915)
 {
 	return false;