drm/i915/gtt: Fold gen8 insertions into one

As we give page directory pointer (lvl 3) structure
for pte insertion, we can fold both versions into
one function by teaching it to get pdp regardless
of top level.

v2: naming and asserts (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190816094754.26492-1-mika.kuoppala@linux.intel.com

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -910,6 +910,23 @@ static inline unsigned int gen8_pd_top_count(const struct i915_address_space *vm
 	return (vm->total + (1ull << shift) - 1) >> shift;
 }
 
+static inline struct i915_page_directory *
+gen8_pdp_for_page_index(struct i915_address_space * const vm, const u64 idx)
+{
+	struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(vm);
+
+	if (vm->top == 2)
+		return ppgtt->pd;
+	else
+		return i915_pd_entry(ppgtt->pd, gen8_pd_index(idx, vm->top));
+}
+
+static inline struct i915_page_directory *
+gen8_pdp_for_page_address(struct i915_address_space * const vm, const u64 addr)
+{
+	return gen8_pdp_for_page_index(vm, addr >> GEN8_PTE_SHIFT);
+}
+
 static void __gen8_ppgtt_cleanup(struct i915_address_space *vm,
 				 struct i915_page_directory *pd,
 				 int count, int lvl)
@@ -1136,12 +1153,12 @@ static inline struct sgt_dma {
 }
 
 static __always_inline u64
-gen8_ppgtt_insert_pte_entries(struct i915_ppgtt *ppgtt,
-			      struct i915_page_directory *pdp,
-			      struct sgt_dma *iter,
-			      u64 idx,
-			      enum i915_cache_level cache_level,
-			      u32 flags)
+gen8_ppgtt_insert_pte(struct i915_ppgtt *ppgtt,
+		      struct i915_page_directory *pdp,
+		      struct sgt_dma *iter,
+		      u64 idx,
+		      enum i915_cache_level cache_level,
+		      u32 flags)
 {
 	struct i915_page_directory *pd;
 	const gen8_pte_t pte_encode = gen8_pte_encode(0, cache_level, flags);
@@ -1182,35 +1199,21 @@ gen8_ppgtt_insert_pte_entries(struct i915_ppgtt *ppgtt,
 	return idx;
 }
 
-static void gen8_ppgtt_insert_3lvl(struct i915_address_space *vm,
-				   struct i915_vma *vma,
+static void gen8_ppgtt_insert_huge(struct i915_vma *vma,
+				   struct sgt_dma *iter,
 				   enum i915_cache_level cache_level,
 				   u32 flags)
-{
-	struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
-	struct sgt_dma iter = sgt_dma(vma);
-
-	gen8_ppgtt_insert_pte_entries(ppgtt, ppgtt->pd, &iter,
-				      vma->node.start >> GEN8_PTE_SHIFT,
-				      cache_level, flags);
-
-	vma->page_sizes.gtt = I915_GTT_PAGE_SIZE;
-}
-
-static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
-					   struct i915_page_directory *pml4,
-					   struct sgt_dma *iter,
-					   enum i915_cache_level cache_level,
-					   u32 flags)
 {
 	const gen8_pte_t pte_encode = gen8_pte_encode(0, cache_level, flags);
 	u64 start = vma->node.start;
 	dma_addr_t rem = iter->sg->length;
 
+	GEM_BUG_ON(!i915_vm_is_4lvl(vma->vm));
+
 	do {
-		struct i915_page_directory *pdp =
-			i915_pd_entry(pml4, __gen8_pte_index(start, 3));
-		struct i915_page_directory *pd =
+		struct i915_page_directory * const pdp =
+			gen8_pdp_for_page_address(vma->vm, start);
+		struct i915_page_directory * const pd =
 			i915_pd_entry(pdp, __gen8_pte_index(start, 2));
 		gen8_pte_t encode = pte_encode;
 		unsigned int maybe_64K = -1;
@@ -1316,26 +1319,26 @@ static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
 	} while (iter->sg);
 }
 
-static void gen8_ppgtt_insert_4lvl(struct i915_address_space *vm,
-				   struct i915_vma *vma,
-				   enum i915_cache_level cache_level,
-				   u32 flags)
+static void gen8_ppgtt_insert(struct i915_address_space *vm,
+			      struct i915_vma *vma,
+			      enum i915_cache_level cache_level,
+			      u32 flags)
 {
-	struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
+	struct i915_ppgtt * const ppgtt = i915_vm_to_ppgtt(vm);
 	struct sgt_dma iter = sgt_dma(vma);
-	struct i915_page_directory * const pml4 = ppgtt->pd;
 
 	if (vma->page_sizes.sg > I915_GTT_PAGE_SIZE) {
-		gen8_ppgtt_insert_huge_entries(vma, pml4, &iter, cache_level,
-					       flags);
-	} else {
+		gen8_ppgtt_insert_huge(vma, &iter, cache_level, flags);
+	} else  {
 		u64 idx = vma->node.start >> GEN8_PTE_SHIFT;
 
-		while ((idx = gen8_ppgtt_insert_pte_entries(ppgtt,
-							    i915_pd_entry(pml4, gen8_pd_index(idx, 3)),
-							    &iter, idx, cache_level,
-							    flags)))
-			;
+		do {
+			struct i915_page_directory * const pdp =
+				gen8_pdp_for_page_index(vm, idx);
+
+			idx = gen8_ppgtt_insert_pte(ppgtt, pdp, &iter, idx,
+						    cache_level, flags);
+		} while (idx);
 
 		vma->page_sizes.gtt = I915_GTT_PAGE_SIZE;
 	}
@@ -1494,18 +1497,15 @@ static struct i915_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
 		goto err_free_scratch;
 	}
 
-	if (i915_vm_is_4lvl(&ppgtt->vm)) {
-		ppgtt->vm.insert_entries = gen8_ppgtt_insert_4lvl;
-	} else {
+	if (!i915_vm_is_4lvl(&ppgtt->vm)) {
 		if (intel_vgpu_active(i915)) {
 			err = gen8_preallocate_top_level_pdp(ppgtt);
 			if (err)
 				goto err_free_pd;
 		}
-
-		ppgtt->vm.insert_entries = gen8_ppgtt_insert_3lvl;
 	}
 
+	ppgtt->vm.insert_entries = gen8_ppgtt_insert;
 	ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc;
 	ppgtt->vm.clear_range = gen8_ppgtt_clear;