drm/i915: Replace some PAGE_SHIFTs with I915_GTT_PAGE_SIZE

Clean up some cases where we're dealing with GTT pages instead of
system pages to use I915_GTT_PAGE_SIZE instead of PAGE_SHIT. So
just replace the the shifts with mul/div as appropriate. These
are the easy ones, the rest probably need some actual thought.

No real changes in the generated asm. Only gen8_ppgtt_insert_4lvl()
was affected as gcc decided to do the following change:
-     be9:       89 d9                   mov    %ebx,%ecx
-     beb:       c1 e1 0c                shl    $0xc,%ecx
-     bee:       48 63 c9                movslq %ecx,%rcx
+     be9:       48 63 cb                movslq %ebx,%rcx
+     bec:       48 c1 e1 0c             shl    $0xc,%rcx
and that then shifted a bunch of the offset by one byte. I presume
the sign extensions in the asm are due to integer promotions from
u16 etc. Hopefully someone has confirmed that those don't end up
doing the wrong thing for us.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180917171414.19220-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -1144,7 +1144,7 @@ static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
 			    vma->page_sizes.sg & I915_GTT_PAGE_SIZE_64K &&
 			    IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_64K) &&
 			    (IS_ALIGNED(rem, I915_GTT_PAGE_SIZE_64K) ||
-			     rem >= (max - index) << PAGE_SHIFT))
+			     rem >= (max - index) * I915_GTT_PAGE_SIZE))
 				maybe_64K = true;
 
 			vaddr = kmap_atomic_px(pt);
@@ -1169,7 +1169,7 @@ static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
 				if (maybe_64K && index < max &&
 				    !(IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_64K) &&
 				      (IS_ALIGNED(rem, I915_GTT_PAGE_SIZE_64K) ||
-				       rem >= (max - index) << PAGE_SHIFT)))
+				       rem >= (max - index) * I915_GTT_PAGE_SIZE)))
 					maybe_64K = false;
 
 				if (unlikely(!IS_ALIGNED(iter->dma, page_size)))
@@ -1842,10 +1842,10 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
 				   u64 start, u64 length)
 {
 	struct gen6_hw_ppgtt *ppgtt = to_gen6_ppgtt(i915_vm_to_ppgtt(vm));
-	unsigned int first_entry = start >> PAGE_SHIFT;
+	unsigned int first_entry = start / I915_GTT_PAGE_SIZE;
 	unsigned int pde = first_entry / GEN6_PTES;
 	unsigned int pte = first_entry % GEN6_PTES;
-	unsigned int num_entries = length >> PAGE_SHIFT;
+	unsigned int num_entries = length / I915_GTT_PAGE_SIZE;
 	const gen6_pte_t scratch_pte = ppgtt->scratch_pte;
 
 	while (num_entries) {
@@ -1886,7 +1886,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
 				      u32 flags)
 {
 	struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
-	unsigned first_entry = vma->node.start >> PAGE_SHIFT;
+	unsigned first_entry = vma->node.start / I915_GTT_PAGE_SIZE;
 	unsigned act_pt = first_entry / GEN6_PTES;
 	unsigned act_pte = first_entry % GEN6_PTES;
 	const u32 pte_encode = vm->pte_encode(0, cache_level, flags);
@@ -2456,7 +2456,7 @@ static void gen8_ggtt_insert_page(struct i915_address_space *vm,
 {
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
 	gen8_pte_t __iomem *pte =
-		(gen8_pte_t __iomem *)ggtt->gsm + (offset >> PAGE_SHIFT);
+		(gen8_pte_t __iomem *)ggtt->gsm + offset / I915_GTT_PAGE_SIZE;
 
 	gen8_set_pte(pte, gen8_pte_encode(addr, level, 0));
 
@@ -2480,7 +2480,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
 	 */
 
 	gtt_entries = (gen8_pte_t __iomem *)ggtt->gsm;
-	gtt_entries += vma->node.start >> PAGE_SHIFT;
+	gtt_entries += vma->node.start / I915_GTT_PAGE_SIZE;
 	for_each_sgt_dma(addr, sgt_iter, vma->pages)
 		gen8_set_pte(gtt_entries++, pte_encode | addr);
 
@@ -2499,7 +2499,7 @@ static void gen6_ggtt_insert_page(struct i915_address_space *vm,
 {
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
 	gen6_pte_t __iomem *pte =
-		(gen6_pte_t __iomem *)ggtt->gsm + (offset >> PAGE_SHIFT);
+		(gen6_pte_t __iomem *)ggtt->gsm + offset / I915_GTT_PAGE_SIZE;
 
 	iowrite32(vm->pte_encode(addr, level, flags), pte);
 
@@ -2519,7 +2519,7 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
 {
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
 	gen6_pte_t __iomem *entries = (gen6_pte_t __iomem *)ggtt->gsm;
-	unsigned int i = vma->node.start >> PAGE_SHIFT;
+	unsigned int i = vma->node.start / I915_GTT_PAGE_SIZE;
 	struct sgt_iter iter;
 	dma_addr_t addr;
 	for_each_sgt_dma(addr, iter, vma->pages)
@@ -2541,8 +2541,8 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm,
 				  u64 start, u64 length)
 {
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
-	unsigned first_entry = start >> PAGE_SHIFT;
-	unsigned num_entries = length >> PAGE_SHIFT;
+	unsigned first_entry = start / I915_GTT_PAGE_SIZE;
+	unsigned num_entries = length / I915_GTT_PAGE_SIZE;
 	const gen8_pte_t scratch_pte =
 		gen8_pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC, 0);
 	gen8_pte_t __iomem *gtt_base =
@@ -2657,8 +2657,8 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
 				  u64 start, u64 length)
 {
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
-	unsigned first_entry = start >> PAGE_SHIFT;
-	unsigned num_entries = length >> PAGE_SHIFT;
+	unsigned first_entry = start / I915_GTT_PAGE_SIZE;
+	unsigned num_entries = length / I915_GTT_PAGE_SIZE;
 	gen6_pte_t scratch_pte, __iomem *gtt_base =
 		(gen6_pte_t __iomem *)ggtt->gsm + first_entry;
 	const int max_entries = ggtt_total_entries(ggtt) - first_entry;
@@ -3398,7 +3398,7 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 	else
 		size = gen8_get_total_gtt_size(snb_gmch_ctl);
 
-	ggtt->vm.total = (size / sizeof(gen8_pte_t)) << PAGE_SHIFT;
+	ggtt->vm.total = (size / sizeof(gen8_pte_t)) * I915_GTT_PAGE_SIZE;
 	ggtt->vm.cleanup = gen6_gmch_remove;
 	ggtt->vm.insert_page = gen8_ggtt_insert_page;
 	ggtt->vm.clear_range = nop_clear_range;
@@ -3456,7 +3456,7 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt)
 	pci_read_config_word(pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
 
 	size = gen6_get_total_gtt_size(snb_gmch_ctl);
-	ggtt->vm.total = (size / sizeof(gen6_pte_t)) << PAGE_SHIFT;
+	ggtt->vm.total = (size / sizeof(gen6_pte_t)) * I915_GTT_PAGE_SIZE;
 
 	ggtt->vm.clear_range = gen6_ggtt_clear_range;
 	ggtt->vm.insert_page = gen6_ggtt_insert_page;