Arm backend: Backend test Ethos-U55/Ethos-U85

Create arm_ethos_u55 and arm_ethos_u85 test flows and add them to CI
Build a semihosted runner for testing on the Corstone3x0 FVP

Signed-off-by: Zingo Andersen <[email protected]>
Change-Id: Icbbbf8a5e796071482a8ad0de290fbaef61e0b04

Author: zingo

.ci/scripts/test_backend.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
+# Copyright 2025 Arm Limited and/or its affiliates.
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
@@ -58,6 +59,12 @@ fi
 if [[ "$FLOW" == *arm* ]]; then
     # Setup ARM deps.
     .ci/scripts/setup-arm-baremetal-tools.sh
+
+    if [[ "$FLOW" == *ethos_u* ]]; then
+        # Prepare a test runner binary that can run on the Corstone-3x0 FVPs
+        backends/arm/scripts/build_executorch.sh
+        backends/arm/test/setup_testing.sh
+    fi
 fi
 
 if [[ $IS_MACOS -eq 1 ]]; then

.github/workflows/test-backend-arm.yml

@@ -23,7 +23,7 @@ jobs:
     uses: ./.github/workflows/_test_backend.yml
     with:
       backend: arm
-      flows: '["arm_tosa_fp", "arm_tosa_int"]'
+      flows: '["arm_tosa_fp", "arm_tosa_int", "arm_ethos_u55", "arm_ethos_u85"]'
       ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
       timeout: 120
       run-linux: true

backends/test/suite/flow.py

@@ -128,13 +128,17 @@ def all_flows() -> dict[str, TestFlow]:
 
     try:
         from executorch.backends.test.suite.flows.arm import (
+            ARM_ETHOS_U55_FLOW,
+            ARM_ETHOS_U85_FLOW,
             ARM_TOSA_FP_FLOW,
             ARM_TOSA_INT_FLOW,
         )
 
         flows += [
             ARM_TOSA_FP_FLOW,
             ARM_TOSA_INT_FLOW,
+            ARM_ETHOS_U55_FLOW,
+            ARM_ETHOS_U85_FLOW,
         ]
     except Exception as e:
         logger.info(f"Skipping ARM flow registration: {e}")

backends/test/suite/flows/arm.py

@@ -58,3 +58,15 @@ def create_quantize_stage() -> Quantize:
     common.get_tosa_compile_spec(tosa_spec="TOSA-1.0+INT"),
     quantize=True,
 )
+
+ARM_ETHOS_U55_FLOW = _create_tosa_flow(
+    "arm_ethos_u55",
+    common.get_u55_compile_spec(),
+    quantize=True,
+)
+
+ARM_ETHOS_U85_FLOW = _create_tosa_flow(
+    "arm_ethos_u85",
+    common.get_u85_compile_spec(),
+    quantize=True,
+)