drm/i915: Store ggtt pointer in intel_gt

This will become useful in the following patch.

v2:
 * Assign the pointer through a helper on the top level to work around
   the layering violation. (Chris)

v3:
 * Handle selftests.

v4:
 * Move call to intel_gt_init_hw into mock_init_ggtt. (Chris)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190621070811.7006-28-tvrtko.ursulin@linux.intel.com

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

@@ -22,6 +22,11 @@ void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915)
 	intel_gt_pm_init_early(gt);
 }
 
+void intel_gt_init_hw(struct drm_i915_private *i915)
+{
+	i915->gt.ggtt = &i915->ggtt;
+}
+
 static void rmw_set(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
 {
 	intel_uncore_rmw(uncore, reg, 0, set);

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

@@ -12,6 +12,7 @@
 struct drm_i915_private;
 
 void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915);
+void intel_gt_init_hw(struct drm_i915_private *i915);
 
 void intel_gt_check_and_clear_faults(struct intel_gt *gt);
 void intel_gt_clear_error_registers(struct intel_gt *gt,

drivers/gpu/drm/i915/gt/intel_gt_types.h

@@ -17,11 +17,13 @@
 #include "intel_wakeref.h"
 
 struct drm_i915_private;
+struct i915_ggtt;
 struct intel_uncore;
 
 struct intel_gt {
 	struct drm_i915_private *i915;
 	struct intel_uncore *uncore;
+	struct i915_ggtt *ggtt;
 
 	struct i915_gt_timelines {
 		struct mutex mutex; /* protects list, tainted by GPU */

drivers/gpu/drm/i915/i915_drv.c

@@ -1593,6 +1593,8 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 	if (ret)
 		goto err_ggtt;
 
+	intel_gt_init_hw(dev_priv);
+
 	ret = i915_ggtt_enable_hw(dev_priv);
 	if (ret) {
 		DRM_ERROR("failed to enable GGTT\n");

drivers/gpu/drm/i915/selftests/mock_gtt.c

@@ -117,6 +117,8 @@ void mock_init_ggtt(struct drm_i915_private *i915, struct i915_ggtt *ggtt)
 	ggtt->vm.vma_ops.clear_pages = clear_pages;
 
 	i915_address_space_init(&ggtt->vm, VM_CLASS_GGTT);
+
+	intel_gt_init_hw(i915);
 }
 
 void mock_fini_ggtt(struct i915_ggtt *ggtt)