MLBEDSW-1971: Verify ifm block size calculation against specification

This commit ensures the IFM block size calculation
in architecture_features.py matches the specification
by correctly setting the ifm upscaling factor based on
the upscaling mode.

This requires adding an attribute to the Tensor object
which stores the upscaling mode for that specific
tensor and making sure that information is correctly
carried over to shared_buffer_allocation.py.

Signed-off-by: Dwight Lidman <dwight.lidman@arm.com>
Change-Id: I4ab56086f4c694d3bf759bbad30cdb969b4a26db

4 files changed, 17 insertions, 6 deletions

diff --git a/ethosu/vela/architecture_features.py b/ethosu/vela/architecture_features.py
index 1bf9d950..b59122ea 100644
--- a/ethosu/vela/architecture_features.py
+++ b/ethosu/vela/architecture_features.py
@@ -22,6 +22,7 @@ from configparser import ConfigParser
 import numpy as np
 
 from .errors import OptionError
+from .ethos_u55_regs.ethos_u55_regs import resampling_mode
 from .numeric_util import round_up
 from .numeric_util import round_up_divide
 from .operation import NpuBlockType
@@ -347,10 +348,10 @@ Note the difference between ArchitectureFeatures and CompilerOptions
         return min(max_block_depth, ifm_depth)
 
     # Calculate the size of the IFM block given a depth, target OFM block and a kernel
-    def get_ifm_block_size(
-        self, ifm_block_depth, ofm_block: Block, kernel: Kernel, subkernel: Block = Block(8, 8, 65536)
-    ):
-        upscaling = 1
+    def get_ifm_block_size(self, ifm_block_depth, ofm_block: Block,
+                           kernel: Kernel, subkernel: Block = Block(8, 8, 65536),
+                           ifm_resampling_mode=resampling_mode.NONE):
+        upscaling = 1 if ifm_resampling_mode == resampling_mode.NONE else 2
         # Height
         ifm_odd_2x_height_enable = 0
         dilated_kernel_height = ((kernel.height - 1) * kernel.dilation.y) + 1
diff --git a/ethosu/vela/shared_buffer_allocation.py b/ethosu/vela/shared_buffer_allocation.py
index 2bfe5941..72caa1b6 100644
--- a/ethosu/vela/shared_buffer_allocation.py
+++ b/ethosu/vela/shared_buffer_allocation.py
@@ -85,6 +85,7 @@ class SharedBufferAllocation:
             else:
                 assert self.ifm_bits == 8, "Unexpected IFM bitdepth"
 
+        self.ifm_resampling_mode = ifm_tensor.resampling_mode
         self.ifm_block_depth = arch.calc_ifm_block_depth(self.ifm_depth, self.ifm_bits)
         self.ofm_tensor = ofm_tensor
 
@@ -105,7 +106,7 @@ class SharedBufferAllocation:
     def try_block(self, ofm_block: Block):
         # Get IFM block configuration
         ifm_block_depth = ofm_block.depth if self.is_equal_depth_op else self.ifm_block_depth
-        ifm_block = self.arch.get_ifm_block_size(ifm_block_depth, ofm_block, self.kernel)
+        ifm_block = self.arch.get_ifm_block_size(ifm_block_depth, ofm_block, self.kernel, ifm_resampling_mode=self.ifm_resampling_mode)
         ifm_config = self.arch.get_block_config(ifm_block.width, ifm_block.height, ifm_block.depth)
         if ifm_config is None:
             return None
diff --git a/ethosu/vela/tensor.py b/ethosu/vela/tensor.py
index 19258b52..160cf630 100644
--- a/ethosu/vela/tensor.py
+++ b/ethosu/vela/tensor.py
@@ -21,6 +21,7 @@ import uuid
 import numpy as np
 
 from . import numeric_util
+from .ethos_u55_regs.ethos_u55_regs import resampling_mode
 from .numeric_util import round_up_divide
 from .range_set import MemoryRangeSet
 
@@ -230,6 +231,7 @@ class Tensor:
         "cpu_tensor",
         "npu_tensor",
         "equivalence_id",
+        "resampling_mode",
     )
     AllocationQuantum = 16
 
@@ -274,6 +276,7 @@ class Tensor:
 
         self.reshaped = False
         self.block_traversal = TensorBlockTraversal.Default
+        self.resampling_mode = resampling_mode.NONE
 
     def element_size(self):
         if self.element_size_bytes == 0:
@@ -312,6 +315,8 @@ class Tensor:
         else:
             res.quantization = None
 
+        res.resampling_mode = self.resampling_mode
+
         return res
 
     def clone_into_fast_storage(self, arch):
diff --git a/ethosu/vela/tflite_reader.py b/ethosu/vela/tflite_reader.py
index 850690f2..4ee39634 100644
--- a/ethosu/vela/tflite_reader.py
+++ b/ethosu/vela/tflite_reader.py
@@ -20,6 +20,7 @@ import os.path
 import numpy as np
 
 from .errors import UnsupportedFeatureError
+from .ethos_u55_regs.ethos_u55_regs import resampling_mode
 from .nn_graph import Graph
 from .nn_graph import Subgraph
 from .operation import Operation
@@ -146,7 +147,8 @@ class TFLiteSubgraph:
             op.attrs = opt_serializer.deserialize(op_data.BuiltinOptions(), op_data.CustomOptionsAsNumpy())
 
             if op_type.startswith("ResizeBilinear"):
-                upscaled_shape = [op.inputs[0].shape[1] * 2, op.inputs[0].shape[2] * 2]
+                input_tensor = op.inputs[0]
+                upscaled_shape = [input_tensor.shape[1] * 2, input_tensor.shape[2] * 2]
                 out_shape = op.outputs[0].shape[1:3]
                 if not op.attrs["align_corners"] and out_shape == upscaled_shape:
                     # this means the output is supposed to be a x2 upscale,
@@ -160,6 +162,8 @@ class TFLiteSubgraph:
                     raise UnsupportedFeatureError("ResizeBilinear: Only 2x upscaling is supported")
                 op.attrs.update({"filter_width": 2, "filter_height": 2, "stride_w": 1, "stride_h": 1})
 
+                input_tensor.resampling_mode = resampling_mode.NEAREST
+
             if "stride_w" in op.attrs:
                 op.attrs["strides"] = (1, op.attrs["stride_h"], op.attrs["stride_w"], 1)
             if "filter_width" in op.attrs: