Add bus_idle test

verification/cocotb/noxfile.py

@@ -312,6 +312,7 @@ def i2c_target_fsm_verify(session, test_group, test_name, coverage, simulator):
         "test_ibi_multi_queue",
         "test_te_errors",
         "test_tsco_violation",
+        "test_bus_idle",
     ],
 )
 @nox.parametrize("coverage", coverage_types)
@@ -339,6 +340,7 @@ def i3c_ahb_verify(session, test_group, test_name, coverage, simulator):
         "test_ibi_multi_queue",
         "test_te_errors",
         "test_tsco_violation",
+        "test_bus_idle",
     ],
 )
 @nox.parametrize("coverage", coverage_types)
@@ -530,6 +532,7 @@ def recovery_pec_verify(session, test_group, test_name, coverage, simulator):
         "test_ibi_multi_queue",
         "test_te_errors",
         "test_tsco_violation",
+        "test_bus_idle",
     ],
 )
 @nox.parametrize("coverage", coverage_types)

verification/cocotb/top/i3c_ahb/test_bus_idle.py

@@ -0,0 +1 @@
+verification/cocotb/top/lib_i3c_top/test_bus_idle.py

verification/cocotb/top/i3c_axi/test_bus_idle.py

@@ -0,0 +1 @@
+verification/cocotb/top/lib_i3c_top/test_bus_idle.py

verification/cocotb/top/lib_i3c_top/test_bus_idle.py

@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: Apache-2.0
+
+import logging
+import cocotb
+from cocotb.triggers import ClockCycles, Timer
+from boot import boot_init
+from i3c_controller_fixed import I3cControllerFixed as I3cController
+from interface import I3CTopTestInterface
+from common import log_seed
+
+
+_BUS_IDLE_PATH = (
+    "xi3c_wrapper.i3c.xcontroller.xcontroller_standby"
+    ".xcontroller_standby_i3c.xbus_timers.bus_idle_o"
+)
+
+
+async def test_setup(dut):
+    cocotb.log.setLevel(logging.DEBUG)
+    log_seed(dut)
+    i3c_controller = I3cController(
+        sda_i=dut.bus_sda, sda_o=dut.sda_sim_ctrl_i,
+        scl_i=dut.bus_scl, scl_o=dut.scl_sim_ctrl_i,
+        debug_state_o=None, speed=12.5e6,
+    )
+    i3c_controller.monitor_enable.clear()
+    await i3c_controller.monitor_idle.wait()
+    dut.sda_sim_target_i.value = 1
+    dut.scl_sim_target_i.value = 1
+    dut.peripheral_reset_done_i.value = 0
+    tb = I3CTopTestInterface(dut)
+    await tb.setup(fclk=333.0)
+    await ClockCycles(tb.clk, 50)
+    await boot_init(tb, fclk=333.0)
+    return i3c_controller, tb
+
+
+@cocotb.test()
+async def test_bus_idle(dut):
+    """
+    Ensures target enters and leaves bus idle state after certain delays.
+    """
+    i3c_controller, tb = await test_setup(dut)
+    bus_idle_sig = getattr(dut, _BUS_IDLE_PATH)
+
+    # 1. Generate a manual STOP condition to start the bus timers
+    # (The timer requires a STOP detection edge to restart its internal counters)
+    dut._log.info("Generating STOP condition (SDA 0->1 while SCL=1) to start bus timers")
+    i3c_controller.scl = 1
+    i3c_controller.sda = 0
+    await Timer(2, "us")
+    i3c_controller.sda = 1  # STOP edge
+    await Timer(2, "us")
+
+    # 2. Wait > 200us for T_IDLE. This forces bus_idle_o to toggle 0 -> 1.
+    dut._log.info("Waiting 210us for bus_idle_o to assert")
+    await Timer(210, "us")
+    assert bus_idle_sig.value == 1, "Target should be in bus idle state"
+
+    # 3. Generate a manual START condition to break the idle state (1 -> 0 toggle)
+    dut._log.info("Generating START condition (SDA 1->0 while SCL=1) to deassert bus_idle_o")
+    i3c_controller.sda = 0
+    await Timer(2, "us")
+    assert bus_idle_sig.value == 0, "Target should not be in bus idle state"
+
+    await tb.teardown()

verification/testplan/source-maps.yml

@@ -39,7 +39,8 @@ testplans:
     testpoints:
     - name: "^(.*)$"
       source: ".*verification/cocotb/top/lib_i3c_top/test_i3c_target.py"
-      cocotb_xml: ".*verification/cocotb/top/i3c_axi/test_i3c_target(_[0-9]+)?.xml"
+      # test_bus_idle here is for bus_idle_coverage
+      cocotb_xml: ".*verification/cocotb/top/i3c_axi/test_(i3c_target|bus_idle)(_[0-9]+)?.xml"
   - name: 'Recovery mode tests'
     testpoints:
     - name: "^(.*)$"

verification/testplan/top/target.hjson

@@ -357,5 +357,15 @@
       tests: [""]
       tags: ["top"]
     }
+    {
+      name: bus_idle
+      desc:
+        '''
+        Generate STOP condition, wait for over 200us and ensure the target entered idle state. Then
+        generate START condition and ensure target left idle state.
+        '''
+      tests: ["bus_idle"]
+      tags: ["top"]
+    }
   ]
 }