[Hexagon] Add default vtcm capacity for targets (#15414)

* [Hexagon] Add default vtcm capacity for targets

This patch adds VTCM default capacity values for different target
architectures so that it can be queried at compile time from targets

* Update test case

Author: quic-sanirudh

python/tvm/target/target.py

@@ -699,14 +699,25 @@ def get_arch_version(cpu_ver):
         msg = "{} is not a valid Hexagon version\nvalid versions include {}"
         raise ValueError(msg.format(cpu_ver, valid_hex)) from None
 
+    def get_vtcm_capacity(cpu_ver):
+        one_mb = 2**20
+        default_vtcm_sizes = {
+            "v65": one_mb // 4,
+            "v66": one_mb // 4,
+            "v68": 4 * one_mb,
+            "v69": 8 * one_mb,
+            "v73": 8 * one_mb,
+        }
+        return default_vtcm_sizes.get(cpu_ver, 0)
+
     # Target configuration:
     arch_version = get_arch_version(cpu_ver)
     config = {
         "hvx": 128,
         "llvm_options": None,
         "use_qfloat": arch_version >= 68,
         "use_ieee_fp": False,
-        "vtcm_capacity": 0,
+        "vtcm_capacity": get_vtcm_capacity(cpu_ver),
     }
     config.update(kwargs)
 

tests/python/contrib/test_hexagon/test_vtcm.py

@@ -79,7 +79,9 @@ def _raises_exception(f):
 
     with tvm.transform.PassContext(config={"tir.vtcm_capacity": vtcm_capacity}):
         assert (
-            _raises_exception(lambda: tvm.build(sch.mod, target=get_hexagon_target("v68")))
+            _raises_exception(
+                lambda: tvm.build(sch.mod, target=get_hexagon_target("v68", vtcm_capacity=0))
+            )
             == limited
         ), "Case 3 - context. VTCM memory allocation limiter does not work correctly "