drm/radeon: add dma engine support for vm pt updates on ni (v5)

Async DMA has a special packet for contiguous pt updates
which saves overhead.

v2: leave the CP method enabled for now as doing the updates
in the DMA rings is not working properly yet.

v3: update for 2 level pts

v4: rebase

v5: drop pte/pde packet.  doesn't seem to work on NI.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/ni.c

@@ -1795,9 +1795,12 @@ void cayman_vm_set_page(struct radeon_device *rdev, uint64_t pe,
 {
 	struct radeon_ring *ring = &rdev->ring[rdev->asic->vm.pt_ring_index];
 	uint32_t r600_flags = cayman_vm_page_flags(rdev, flags);
+	uint64_t value;
+	unsigned ndw;
 
+	if (rdev->asic->vm.pt_ring_index == RADEON_RING_TYPE_GFX_INDEX) {
 		while (count) {
-		unsigned ndw = 1 + count * 2;
+			ndw = 1 + count * 2;
 			if (ndw > 0x3FFF)
 				ndw = 0x3FFF;
 
@@ -1805,22 +1808,46 @@ void cayman_vm_set_page(struct radeon_device *rdev, uint64_t pe,
 			radeon_ring_write(ring, pe);
 			radeon_ring_write(ring, upper_32_bits(pe) & 0xff);
 			for (; ndw > 1; ndw -= 2, --count, pe += 8) {
-			uint64_t value = 0;
 				if (flags & RADEON_VM_PAGE_SYSTEM) {
 					value = radeon_vm_map_gart(rdev, addr);
 					value &= 0xFFFFFFFFFFFFF000ULL;
-				addr += incr;
-
 				} else if (flags & RADEON_VM_PAGE_VALID) {
 					value = addr;
+				} else {
+					value = 0;
+				}
 				addr += incr;
+				value |= r600_flags;
+				radeon_ring_write(ring, value);
+				radeon_ring_write(ring, upper_32_bits(value));
+			}
 		}
+	} else {
+		while (count) {
+			ndw = count * 2;
+			if (ndw > 0xFFFFE)
+				ndw = 0xFFFFE;
 
+			/* for non-physically contiguous pages (system) */
+			radeon_ring_write(ring, DMA_PACKET(DMA_PACKET_WRITE, 0, 0, ndw));
+			radeon_ring_write(ring, pe);
+			radeon_ring_write(ring, upper_32_bits(pe) & 0xff);
+			for (; ndw > 0; ndw -= 2, --count, pe += 8) {
+				if (flags & RADEON_VM_PAGE_SYSTEM) {
+					value = radeon_vm_map_gart(rdev, addr);
+					value &= 0xFFFFFFFFFFFFF000ULL;
+				} else if (flags & RADEON_VM_PAGE_VALID) {
+					value = addr;
+				} else {
+					value = 0;
+				}
+				addr += incr;
 				value |= r600_flags;
 				radeon_ring_write(ring, value);
 				radeon_ring_write(ring, upper_32_bits(value));
 			}
 		}
+	}
 }
 
 /**