[PATCH 1/2] drm/amdgpu: reverse PDBs order

[Chunming Zhou]

The hiberachy of page table is as below, which aligns hw names.
PDB2->PDB1->PDB0->PTB, accordingly:
level3 --- PDB2
level2 --- PDB1
level1 --- PDB0
level0 --- PTB

Change-Id: I2d748e5e96cffe18294c104c4b192d910b2f8e6b
Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 37 ++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 3ecdbdfb04dd..8904ccf78fc9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -148,8 +148,8 @@ struct amdgpu_prt_cb {
 static unsigned amdgpu_vm_level_shift(struct amdgpu_device *adev,
 				      unsigned level)
 {
-	if (level != adev->vm_manager.num_level)
-		return 9 * (adev->vm_manager.num_level - level - 1) +
+	if (level != 0)
+		return 9 * (level - 1) +
 			adev->vm_manager.block_size;
 	else
 		/* For the page tables on the leaves */
@@ -162,20 +162,27 @@ static unsigned amdgpu_vm_level_shift(struct amdgpu_device *adev,
  * @adev: amdgpu_device pointer
  *
  * Calculate the number of entries in a page directory or page table.
+ * The hiberachy of page table is as below, which aligns hw names.
+ * PDB2->PDB1->PDB0->PTB, accordingly:
+ * level3 --- PDB2
+ * level2 --- PDB1
+ * level1 --- PDB0
+ * level0 --- PTB
  */
 static unsigned amdgpu_vm_num_entries(struct amdgpu_device *adev,
 				      unsigned level)
 {
-	unsigned shift = amdgpu_vm_level_shift(adev, 0);
+	unsigned shift = amdgpu_vm_level_shift(adev,
+					       adev->vm_manager.num_level);
 
-	if (level == 0)
+	if (level == adev->vm_manager.num_level)
 		/* For the root directory */
 		return round_up(adev->vm_manager.max_pfn, 1 << shift) >> shift;
-	else if (level != adev->vm_manager.num_level)
+	else if (level != 0)
 		/* Everything in between */
 		return 512;
 	else
-		/* For the page tables on the leaves */
+		/* For the page tables on the leaves(PTB) */
 		return AMDGPU_VM_PTE_COUNT(adev);
 }
 
@@ -312,6 +319,8 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
 	u64 flags;
 	uint64_t init_value = 0;
 
+	BUG_ON(level > adev->vm_manager.num_level);
+
 	if (!parent->entries) {
 		unsigned num_entries = amdgpu_vm_num_entries(adev, level);
 
@@ -332,7 +341,7 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
 	if (to > parent->last_entry_used)
 		parent->last_entry_used = to;
 
-	++level;
+	level--;
 	saddr = saddr & ((1 << shift) - 1);
 	eaddr = eaddr & ((1 << shift) - 1);
 
@@ -346,7 +355,8 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
 
 	if (vm->pte_support_ats) {
 		init_value = AMDGPU_PTE_DEFAULT_ATC;
-		if (level != adev->vm_manager.num_level - 1)
+		/* != PDB0 */
+		if (level != 1)
 			init_value |= AMDGPU_PDE_PTE;
 
 	}
@@ -389,7 +399,7 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
 			entry->addr = 0;
 		}
 
-		if (level < adev->vm_manager.num_level) {
+		if (level > 0) {
 			uint64_t sub_saddr = (pt_idx == from) ? saddr : 0;
 			uint64_t sub_eaddr = (pt_idx == to) ? eaddr :
 				((1 << shift) - 1);
@@ -435,7 +445,8 @@ int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
 	saddr /= AMDGPU_GPU_PAGE_SIZE;
 	eaddr /= AMDGPU_GPU_PAGE_SIZE;
 
-	return amdgpu_vm_alloc_levels(adev, vm, &vm->root, saddr, eaddr, 0);
+	return amdgpu_vm_alloc_levels(adev, vm, &vm->root, saddr, eaddr,
+				      adev->vm_manager.num_level);
 }
 
 /**
@@ -1319,19 +1330,19 @@ void amdgpu_vm_get_entry(struct amdgpu_pte_update_params *p, uint64_t addr,
 			 struct amdgpu_vm_pt **entry,
 			 struct amdgpu_vm_pt **parent)
 {
-	unsigned level = 0;
+	unsigned level = p->adev->vm_manager.num_level;
 
 	*parent = NULL;
 	*entry = &p->vm->root;
 	while ((*entry)->entries) {
-		unsigned idx = addr >> amdgpu_vm_level_shift(p->adev, level++);
+		unsigned idx = addr >> amdgpu_vm_level_shift(p->adev, level--);
 
 		idx %= amdgpu_bo_size((*entry)->base.bo) / 8;
 		*parent = *entry;
 		*entry = &(*entry)->entries[idx];
 	}
 
-	if (level != p->adev->vm_manager.num_level)
+	if (level != 0)
 		*entry = NULL;
 }
 
-- 
2.14.1