drm/i915: allocate i915->gt0 dynamically

Convert i915->gt0 to a pointer, and allocate it dynamically.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Acked-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/01bf968aa431b77d491790178cbeece18b5fc4c0.1696236329.git.jani.nikula@intel.com

drivers/gpu/drm/i915/gt/intel_gt.c

@@ -62,7 +62,13 @@ void intel_gt_common_init_early(struct intel_gt *gt)
 /* Preliminary initialization of Tile 0 */
 int intel_root_gt_init_early(struct drm_i915_private *i915)
 {
-	struct intel_gt *gt = to_gt(i915);
+	struct intel_gt *gt;
+
+	gt = drmm_kzalloc(&i915->drm, sizeof(*gt), GFP_KERNEL);
+	if (!gt)
+		return -ENOMEM;
+
+	i915->gt0 = gt;
 
 	gt->i915 = i915;
 	gt->uncore = &i915->uncore;

drivers/gpu/drm/i915/i915_drv.h

@@ -318,10 +318,10 @@ struct drm_i915_private {
 	struct i915_hwmon *hwmon;
 
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
-	struct intel_gt gt0;
+	struct intel_gt *gt0;
 
 	/*
-	 * i915->gt[0] == &i915->gt0
+	 * i915->gt[0] == i915->gt0
 	 */
 	struct intel_gt *gt[I915_MAX_GT];
 
@@ -382,9 +382,9 @@ static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
 	return pci_get_drvdata(pdev);
 }
 
-static inline struct intel_gt *to_gt(struct drm_i915_private *i915)
+static inline struct intel_gt *to_gt(const struct drm_i915_private *i915)
 {
-	return &i915->gt0;
+	return i915->gt0;
 }
 
 /* Simple iterator over all initialised engines */