Arm backend: Bump to 2026.05 release of tosa-tools

Bump the release to 2026.05 and enable the compatibility flag
for the serialization to make current and older versions of
model-converter being able to deserialize the resulting flatbuffer
file.

Signed-off-by: Per Åstrand <per.astrand@arm.com>
Change-Id: I717d59011bd211e3586e656a8dad62e77a8660dd

Author: per

backends/arm/common/arm_compile_spec.py

@@ -37,6 +37,7 @@ class DebugMode(Enum):
     path_for_intermediates: str | None = None
     tosa_debug_mode: DebugMode | None = None
     preserve_io_quantization: bool = False
+    tosa_dev_mode: bool | None = None
 
     _TOSA_SPEC_KEY = "tosa_spec"
     _COMPILE_FLAGS_KEY = "compile_flags"
@@ -46,6 +47,7 @@ class DebugMode(Enum):
     _OUTPUT_REORDER_KEY = "ouput_reorder_workaround"
     _TRANSFORM_PIPELINE_CONFIG_KEY = "transform_pipeline_config"
     _PRESERVE_IO_QUANT_KEY = "preserve_io_quantization"
+    _TOSA_DEV_MODE = "tosa_sw_dev_mode"
 
     def _set_compile_specs(
         self,
@@ -56,6 +58,7 @@ def _set_compile_specs(
         output_order_workaround: bool = False,
         pipeline_config: ArmPassPipelineConfig | None = None,
         preserve_io_quantization: bool = False,
+        tosa_dev_mode: bool | None = None,
     ):
         """Set all values of dataclass directly."""
         self.tosa_spec = tosa_spec
@@ -66,6 +69,7 @@ def _set_compile_specs(
         self.output_order_workaround = output_order_workaround
         self.preserve_io_quantization = preserve_io_quantization
         self._warn_if_redundant_preserve_io_quantization()
+        self.tosa_dev_mode = tosa_dev_mode
         if output_order_workaround:
             warnings.warn(
                 "ArmCompileSpec(output_order_workaround=True) is deprecated and will be "
@@ -84,6 +88,7 @@ def _from_list(cls, compile_specs: list[CompileSpec]):  # noqa: C901
         output_order_workaround: bool = False
         pipeline_config: ArmPassPipelineConfig | None = None
         preserve_io_quantization: bool = False
+        tosa_dev_mode: bool | None = None
         unknown_specs: dict[str, str] = {}
         for spec in compile_specs:
             key = spec.key
@@ -136,6 +141,12 @@ def _from_list(cls, compile_specs: list[CompileSpec]):  # noqa: C901
                 pipeline_config = ArmPassPipelineConfig.from_dict(json.loads(val))
             elif key == ArmCompileSpec._PRESERVE_IO_QUANT_KEY:
                 preserve_io_quantization = str(val).lower() in ("1", "true", "yes")
+            elif key == ArmCompileSpec._TOSA_DEV_MODE:
+                if tosa_dev_mode is not None:
+                    raise ValueError(
+                        "More than one tosa_sw_dev_mode entry in compile spec."
+                    )
+                tosa_dev_mode = str(val).lower() in ("1", "true", "yes")
             else:
                 unknown_specs[key] = val
 
@@ -160,6 +171,7 @@ def _from_list(cls, compile_specs: list[CompileSpec]):  # noqa: C901
             output_order_workaround=output_order_workaround,
             pipeline_config=pipeline_config,
             preserve_io_quantization=preserve_io_quantization,
+            tosa_dev_mode=tosa_dev_mode,
         )
         cls._from_list_hook(compile_spec, unknown_specs)
         compile_spec._validate()
@@ -242,6 +254,15 @@ def _to_list(self):
                 str(bool(self.preserve_io_quantization)).encode(),
             )
         )
+
+        if self.tosa_dev_mode is not None:
+            compile_spec.append(
+                CompileSpec(
+                    ArmCompileSpec._TOSA_DEV_MODE,
+                    str(bool(self.tosa_dev_mode)).encode(),
+                )
+            )
+
         return compile_spec
 
     def _set_preserve_io_quantization(self, enabled: bool) -> "ArmCompileSpec":
@@ -326,6 +347,16 @@ def dump_debug_info(self, debug_mode: DebugMode | None):
         self.tosa_debug_mode = debug_mode
         return self
 
+    def _set_tosa_dev_mode(self, tosa_dev_mode: bool):
+        """Sets whether to enable TOSA software development mode.
+
+        Args:
+            tosa_dev_mode: Boolean indicating whether to enable TOSA software development mode.
+
+        """
+        self.tosa_dev_mode = tosa_dev_mode
+        return self
+
     @deprecated(
         "set_output_order_workaround() is deprecated and will be removed in v1.5; please remove this call."
     )

backends/arm/requirements-arm-tosa.txt

@@ -10,4 +10,4 @@ flatbuffers == 24.3.25
 tosa-adapter-model-explorer == 0.1.0
 ai-edge-model-explorer >= 0.1.16
 pytest-timeout == 2.4.0
-tosa-tools == 2026.2.1
+tosa-tools == 2026.5.0

backends/arm/test/misc/test_compile_spec.py

@@ -94,6 +94,12 @@ def test_preserve_io_quantization_roundtrip_vgf_FP_INT():
     assert roundtripped.preserve_io_quantization is True
 
 
+def test_preserve_tosa_dev_mode_roundtrip_vgf_FP_INT():
+    compile_spec = VgfCompileSpec()
+    roundtripped = VgfCompileSpec._from_list(compile_spec._to_list())
+    assert roundtripped.tosa_dev_mode is True
+
+
 def test_preserve_io_quantization_warns_for_u55_INT():
     with warns(
         UserWarning,

backends/arm/tosa/backend.py

@@ -232,6 +232,9 @@ def _preprocess(  # noqa: C901
             targetDraft=True if version.minor > 0 else False,
         )
 
+        if compile_spec.tosa_dev_mode:
+            tosa_graph.setExperimentalDevVersion()
+
         if not (
             tosa_spec.version.major == ts.TOSA_VERSION_MAJOR
             and tosa_spec.version.minor <= ts.TOSA_VERSION_MINOR
@@ -484,4 +487,5 @@ def filter_tosa_compile_specs(
             )
             .dump_debug_info(compile_spec.tosa_debug_mode)
             .set_output_order_workaround(compile_spec.output_order_workaround)
+            ._set_tosa_dev_mode(compile_spec.tosa_dev_mode)
         )