drm/i915: Convert i915_gem_flush_ggtt_writes to intel_gt

Having introduced struct intel_gt (named the anonymous structure in i915)
we can start using it to compartmentalize our code better. It makes more
sense logically to have the code internally like this and it will also
help with future split between gt and display in i915.

v2:
 * Keep ggtt flush before fb obj flush. (Chris)

v3:
 * Fix refactoring fail.
 * Always flush ggtt writes. (Chris)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190621070811.7006-23-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -23,7 +23,7 @@
  */
 
 #include "display/intel_frontbuffer.h"
-
+#include "gt/intel_gt.h"
 #include "i915_drv.h"
 #include "i915_gem_clflush.h"
 #include "i915_gem_context.h"
@@ -319,7 +319,6 @@ void
 i915_gem_object_flush_write_domain(struct drm_i915_gem_object *obj,
 				   unsigned int flush_domains)
 {
-	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 	struct i915_vma *vma;
 
 	assert_object_held(obj);
@@ -329,7 +328,8 @@ i915_gem_object_flush_write_domain(struct drm_i915_gem_object *obj,
 
 	switch (obj->write_domain) {
 	case I915_GEM_DOMAIN_GTT:
-		i915_gem_flush_ggtt_writes(dev_priv);
+		for_each_ggtt_vma(vma, obj)
+			intel_gt_flush_ggtt_writes(vma->vm->gt);
 
 		intel_fb_obj_flush(obj,
 				   fb_write_origin(obj, I915_GEM_DOMAIN_GTT));
@@ -340,6 +340,7 @@ i915_gem_object_flush_write_domain(struct drm_i915_gem_object *obj,
 
 			i915_vma_unset_ggtt_write(vma);
 		}
+
 		break;
 
 	case I915_GEM_DOMAIN_WC:

drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c

@@ -6,6 +6,7 @@
 
 #include <linux/prime_numbers.h>
 
+#include "gt/intel_gt.h"
 #include "gt/intel_gt_pm.h"
 #include "huge_gem_object.h"
 #include "i915_selftest.h"
@@ -143,7 +144,7 @@ static int check_partial_mapping(struct drm_i915_gem_object *obj,
 		if (offset >= obj->base.size)
 			continue;
 
-		i915_gem_flush_ggtt_writes(to_i915(obj->base.dev));
+		intel_gt_flush_ggtt_writes(&to_i915(obj->base.dev)->gt);
 
 		p = i915_gem_object_get_page(obj, offset >> PAGE_SHIFT);
 		cpu = kmap(p) + offset_in_page(offset);

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

@@ -150,3 +150,44 @@ void intel_gt_check_and_clear_faults(struct intel_gt *gt)
 
 	intel_gt_clear_error_registers(gt, ALL_ENGINES);
 }
+
+void intel_gt_flush_ggtt_writes(struct intel_gt *gt)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	intel_wakeref_t wakeref;
+
+	/*
+	 * No actual flushing is required for the GTT write domain for reads
+	 * from the GTT domain. Writes to it "immediately" go to main memory
+	 * as far as we know, so there's no chipset flush. It also doesn't
+	 * land in the GPU render cache.
+	 *
+	 * However, we do have to enforce the order so that all writes through
+	 * the GTT land before any writes to the device, such as updates to
+	 * the GATT itself.
+	 *
+	 * We also have to wait a bit for the writes to land from the GTT.
+	 * An uncached read (i.e. mmio) seems to be ideal for the round-trip
+	 * timing. This issue has only been observed when switching quickly
+	 * between GTT writes and CPU reads from inside the kernel on recent hw,
+	 * and it appears to only affect discrete GTT blocks (i.e. on LLC
+	 * system agents we cannot reproduce this behaviour, until Cannonlake
+	 * that was!).
+	 */
+
+	wmb();
+
+	if (INTEL_INFO(i915)->has_coherent_ggtt)
+		return;
+
+	i915_gem_chipset_flush(i915);
+
+	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
+		struct intel_uncore *uncore = gt->uncore;
+
+		spin_lock_irq(&uncore->lock);
+		intel_uncore_posting_read_fw(uncore,
+					     RING_HEAD(RENDER_RING_BASE));
+		spin_unlock_irq(&uncore->lock);
+	}
+}

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

@@ -17,4 +17,6 @@ void intel_gt_check_and_clear_faults(struct intel_gt *gt);
 void intel_gt_clear_error_registers(struct intel_gt *gt,
 				    intel_engine_mask_t engine_mask);
 
+void intel_gt_flush_ggtt_writes(struct intel_gt *gt);
+
 #endif /* __INTEL_GT_H__ */

drivers/gpu/drm/i915/i915_drv.h

@@ -2599,8 +2599,6 @@ int __must_check i915_gem_evict_for_node(struct i915_address_space *vm,
 					 unsigned int flags);
 int i915_gem_evict_vm(struct i915_address_space *vm);
 
-void i915_gem_flush_ggtt_writes(struct drm_i915_private *dev_priv);
-
 /* belongs in i915_gem_gtt.h */
 static inline void i915_gem_chipset_flush(struct drm_i915_private *dev_priv)
 {

drivers/gpu/drm/i915/i915_gem.c

@@ -233,46 +233,6 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
 			       &args->size, &args->handle);
 }
 
-void i915_gem_flush_ggtt_writes(struct drm_i915_private *dev_priv)
-{
-	intel_wakeref_t wakeref;
-
-	/*
-	 * No actual flushing is required for the GTT write domain for reads
-	 * from the GTT domain. Writes to it "immediately" go to main memory
-	 * as far as we know, so there's no chipset flush. It also doesn't
-	 * land in the GPU render cache.
-	 *
-	 * However, we do have to enforce the order so that all writes through
-	 * the GTT land before any writes to the device, such as updates to
-	 * the GATT itself.
-	 *
-	 * We also have to wait a bit for the writes to land from the GTT.
-	 * An uncached read (i.e. mmio) seems to be ideal for the round-trip
-	 * timing. This issue has only been observed when switching quickly
-	 * between GTT writes and CPU reads from inside the kernel on recent hw,
-	 * and it appears to only affect discrete GTT blocks (i.e. on LLC
-	 * system agents we cannot reproduce this behaviour, until Cannonlake
-	 * that was!).
-	 */
-
-	wmb();
-
-	if (INTEL_INFO(dev_priv)->has_coherent_ggtt)
-		return;
-
-	i915_gem_chipset_flush(dev_priv);
-
-	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref) {
-		struct intel_uncore *uncore = &dev_priv->uncore;
-
-		spin_lock_irq(&uncore->lock);
-		intel_uncore_posting_read_fw(uncore,
-					     RING_HEAD(RENDER_RING_BASE));
-		spin_unlock_irq(&uncore->lock);
-	}
-}
-
 static int
 shmem_pread(struct page *page, int offset, int len, char __user *user_data,
 	    bool needs_clflush)

drivers/gpu/drm/i915/i915_vma.c

@@ -27,6 +27,7 @@
 #include "display/intel_frontbuffer.h"
 
 #include "gt/intel_engine.h"
+#include "gt/intel_gt.h"
 
 #include "i915_drv.h"
 #include "i915_globals.h"
@@ -408,7 +409,7 @@ void i915_vma_flush_writes(struct i915_vma *vma)
 	if (!i915_vma_has_ggtt_write(vma))
 		return;
 
-	i915_gem_flush_ggtt_writes(vma->vm->i915);
+	intel_gt_flush_ggtt_writes(vma->vm->gt);
 
 	i915_vma_unset_ggtt_write(vma);
 }

drivers/gpu/drm/i915/selftests/i915_gem_gtt.c

@@ -1193,7 +1193,7 @@ static int igt_ggtt_page(void *arg)
 		iowrite32(n, vaddr + n);
 		io_mapping_unmap_atomic(vaddr);
 	}
-	i915_gem_flush_ggtt_writes(i915);
+	intel_gt_flush_ggtt_writes(ggtt->vm.gt);
 
 	i915_random_reorder(order, count, &prng);
 	for (n = 0; n < count; n++) {