AXI4 Interface and Functional Modeling

lib/src/interfaces/interfaces.dart

@@ -2,3 +2,4 @@
 // SPDX-License-Identifier: BSD-3-Clause
 
 export 'apb.dart';
+export 'axi4.dart';

lib/src/models/axi4_bfm/axi4_bfm.dart

@@ -0,0 +1,10 @@
+// Copyright (C) 2024-2025 Intel Corporation
+// SPDX-License-Identifier: BSD-3-Clause
+
+export 'axi4_compliance_checker.dart';
+export 'axi4_main.dart';
+export 'axi4_main_driver.dart';
+export 'axi4_monitor.dart';
+export 'axi4_packet.dart';
+export 'axi4_subordinate.dart';
+export 'axi4_tracker.dart';

lib/src/models/axi4_bfm/axi4_compliance_checker.dart

@@ -0,0 +1,128 @@
+// Copyright (C) 2024-2025 Intel Corporation
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// axi4_compliance_checker.dart
+// Compliance checking for AXI4.
+//
+// 2025 January
+// Author: Josh Kimmel <joshua1.kimmel@intel.com>
+
+import 'dart:async';
+
+import 'package:rohd_hcl/rohd_hcl.dart';
+import 'package:rohd_vf/rohd_vf.dart';
+
+/// A checker for some of the rules defined in the AXI4 interface specification.
+///
+/// This does not necessarily cover all rules defined in the spec.
+class Axi4ComplianceChecker extends Component {
+  /// AXI4 System Interface.
+  final Axi4SystemInterface sIntf;
+
+  /// AXI4 Read Interface.
+  final Axi4ReadInterface rIntf;
+
+  /// AXI4 Write Interface.
+  final Axi4WriteInterface wIntf;
+
+  /// Creates a new compliance checker for AXI4.
+  Axi4ComplianceChecker(
+    this.sIntf,
+    this.rIntf,
+    this.wIntf, {
+    required Component parent,
+    String name = 'axi4ComplianceChecker',
+  }) : super(name, parent);
+
+  @override
+  Future<void> run(Phase phase) async {
+    unawaited(super.run(phase));
+
+    // wait for reset to complete
+    await sIntf.resetN.nextPosedge;
+
+    // checks to run
+    // READ REQUESTS
+    //   number of flits returned matches ARLEN if no error
+    //   if RLAST is present, asserted on the final flit only
+    //   if RID is present, every read response should match
+    //   a pending request ARID
+    // WRITE REQUESTS
+    //   number of flits sent matches AWLEN
+    //   WLAST is asserted on the final flit only
+    //   if BID is present, every write response should match
+    //   a pending request AWID
+
+    final rLastPresent = rIntf.rLast != null;
+
+    final readReqMap = <int, List<int>>{};
+    final writeReqMap = <int, List<int>>{};
+    var lastWriteReqId = -1;
+
+    sIntf.clk.posedge.listen((event) {
+      // capture read requests for counting
+      if (rIntf.arValid.previousValue!.isValid &&
+          rIntf.arValid.previousValue!.toBool()) {
+        final id = rIntf.arId?.previousValue?.toInt() ?? 0;
+        final len = (rIntf.arLen?.previousValue?.toInt() ?? 0) + 1;
+        readReqMap[id] = [len, 0];
+      }
+
+      // track read response flits
+      if (rIntf.rValid.previousValue!.isValid &&
+          rIntf.rValid.previousValue!.toBool()) {
+        final id = rIntf.rId?.previousValue?.toInt() ?? 0;
+        if (!readReqMap.containsKey(id)) {
+          logger.severe(
+              'Cannot match a read response to any pending read request. '
+              'ID captured by the response was $id.');
+        }
+
+        readReqMap[id]![1] = readReqMap[id]![1] + 1;
+        final len = readReqMap[id]![0];
+        final currCount = readReqMap[id]![1];
+        if (currCount > len) {
+          logger.severe(
+              'Received more read response data flits than indicated by the '
+              'request with ID $id ARLEN. Expected $len but got $currCount');
+        } else if (currCount == len &&
+            rLastPresent &&
+            !rIntf.rLast!.previousValue!.toBool()) {
+          logger.severe('Received the final flit in the read response data per '
+              'the request with ID $id ARLEN but RLAST is not asserted.');
+        }
+      }
+
+      // track write requests
+      if (wIntf.awValid.previousValue!.isValid &&
+          wIntf.awValid.previousValue!.toBool()) {
+        final id = wIntf.awId?.previousValue?.toInt() ?? 0;
+        final len = (wIntf.awLen?.previousValue?.toInt() ?? 0) + 1;
+        writeReqMap[id] = [len, 0];
+        lastWriteReqId = id;
+      }
+
+      // track write data flits
+      if (wIntf.wValid.previousValue!.isValid &&
+          wIntf.wValid.previousValue!.toBool()) {
+        final id = lastWriteReqId;
+        if (!writeReqMap.containsKey(id)) {
+          logger.severe('There is no pending write request '
+              'to associate with valid write data.');
+        }
+
+        writeReqMap[id]![1] = writeReqMap[id]![1] + 1;
+        final len = writeReqMap[id]![0];
+        final currCount = writeReqMap[id]![1];
+        if (currCount > len) {
+          logger.severe(
+              'Sent more write data flits than indicated by the request '
+              'with ID $id AWLEN. Expected $len but sent $currCount');
+        } else if (currCount == len && !wIntf.wLast.previousValue!.toBool()) {
+          logger.severe('Sent the final flit in the write data per the request '
+              'with ID $id AWLEN but WLAST is not asserted.');
+        }
+      }
+    });
+  }
+}

lib/src/models/axi4_bfm/axi4_main.dart

@@ -0,0 +1,62 @@
+// Copyright (C) 2024-2025 Intel Corporation
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// axi4_main.dart
+// An agent sending for AXI4 requests.
+//
+// 2025 January
+// Author: Josh Kimmel <joshua1.kimmel@intel.com>
+
+import 'package:rohd_hcl/rohd_hcl.dart';
+import 'package:rohd_hcl/src/models/axi4_bfm/axi4_bfm.dart';
+import 'package:rohd_vf/rohd_vf.dart';
+
+/// An agent for sending requests on [Axi4ReadInterface]s and [Axi4WriteInterface]s.
+///
+/// Driven read packets will update the returned data into the same packet.
+class Axi4MainAgent extends Agent {
+  /// AXI4 System Interface.
+  final Axi4SystemInterface sIntf;
+
+  /// AXI4 Read Interface.
+  final Axi4ReadInterface rIntf;
+
+  /// AXI4 Write Interface.
+  final Axi4WriteInterface wIntf;
+
+  /// The sequencer where requests should be sent.
+  late final Sequencer<Axi4RequestPacket> sequencer;
+
+  /// The driver that sends the requests over the interface.
+  late final Axi4MainDriver driver;
+
+  /// The number of cycles before timing out if no transactions can be sent.
+  final int timeoutCycles;
+
+  /// The number of cycles before an objection will be dropped when there are
+  /// no pending packets to send.
+  final int dropDelayCycles;
+
+  /// Constructs a new [Axi4MainAgent].
+  Axi4MainAgent({
+    required this.sIntf,
+    required this.rIntf,
+    required this.wIntf,
+    required Component parent,
+    String name = 'axiMainAgent',
+    this.timeoutCycles = 500,
+    this.dropDelayCycles = 30,
+  }) : super(name, parent) {
+    sequencer = Sequencer<Axi4RequestPacket>('sequencer', this);
+
+    driver = Axi4MainDriver(
+      parent: this,
+      sIntf: sIntf,
+      rIntf: rIntf,
+      wIntf: wIntf,
+      sequencer: sequencer,
+      timeoutCycles: timeoutCycles,
+      dropDelayCycles: dropDelayCycles,
+    );
+  }
+}