diff --git a/tests/Makefile b/tests/Makefile
index eff5e11..ef1e981 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -152,6 +152,7 @@ check-qtest-i386-y += tests/i440fx-test$(EXESUF)
 check-qtest-i386-y += tests/fw_cfg-test$(EXESUF)
 check-qtest-i386-y += tests/drive_del-test$(EXESUF)
 check-qtest-i386-y += tests/wdt_ib700-test$(EXESUF)
+check-qtest-i386-y += tests/tco-test$(EXESUF)
 gcov-files-i386-y += hw/watchdog/watchdog.c hw/watchdog/wdt_ib700.c
 check-qtest-i386-y += $(check-qtest-pci-y)
 gcov-files-i386-y += $(gcov-files-pci-y)
@@ -370,6 +371,7 @@ tests/eepro100-test$(EXESUF): tests/eepro100-test.o
 tests/vmxnet3-test$(EXESUF): tests/vmxnet3-test.o
 tests/ne2000-test$(EXESUF): tests/ne2000-test.o
 tests/wdt_ib700-test$(EXESUF): tests/wdt_ib700-test.o
+tests/tco-test$(EXESUF): tests/tco-test.o $(libqos-pc-obj-y)
 tests/virtio-balloon-test$(EXESUF): tests/virtio-balloon-test.o
 tests/virtio-blk-test$(EXESUF): tests/virtio-blk-test.o $(libqos-virtio-obj-y)
 tests/virtio-net-test$(EXESUF): tests/virtio-net-test.o $(libqos-pc-obj-y)
diff --git a/tests/tco-test.c b/tests/tco-test.c
new file mode 100644
index 0000000..79a673e
--- /dev/null
+++ b/tests/tco-test.c
@@ -0,0 +1,460 @@
+/*
+ * QEMU ICH9 TCO emulation tests
+ *
+ * Copyright (c) 2015 Paulo Alcantara <pcacjr@zytor.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include <glib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libqtest.h"
+#include "libqos/pci.h"
+#include "libqos/pci-pc.h"
+#include "hw/pci/pci_regs.h"
+#include "hw/i386/ich9.h"
+#include "hw/i386/ich9-cc.h"
+#include "hw/acpi/ich9.h"
+#include "hw/acpi/tco.h"
+
+#define PM_IO_BASE_ADDR 0xb000
+
+enum {
+    TCO_RLD_DEFAULT         = 0x0000,
+    TCO_DAT_IN_DEFAULT      = 0x00,
+    TCO_DAT_OUT_DEFAULT     = 0x00,
+    TCO1_STS_DEFAULT        = 0x0000,
+    TCO2_STS_DEFAULT        = 0x0000,
+    TCO1_CNT_DEFAULT        = 0x0000,
+    TCO2_CNT_DEFAULT        = 0x0008,
+    TCO_MESSAGE1_DEFAULT    = 0x00,
+    TCO_MESSAGE2_DEFAULT    = 0x00,
+    TCO_WDCNT_DEFAULT       = 0x00,
+    TCO_TMR_DEFAULT         = 0x0004,
+    SW_IRQ_GEN_DEFAULT      = 0x03,
+};
+
+#define TCO_SECS_TO_TICKS(secs)     (((secs) * 10) / 6)
+#define TCO_TICKS_TO_SECS(ticks)    (((ticks) * 6) / 10)
+
+typedef struct {
+    const char *args;
+    QPCIDevice *dev;
+    void *lpc_base;
+    void *tco_io_base;
+} TestData;
+
+static void test_init(TestData *d)
+{
+    QPCIBus *bus;
+    QTestState *qs;
+    char *s;
+
+    s = g_strdup_printf("-machine q35 %s", !d->args ? "" : d->args);
+    qs = qtest_start(s);
+    qtest_irq_intercept_in(qs, "ioapic");
+    g_free(s);
+
+    bus = qpci_init_pc();
+    d->dev = qpci_device_find(bus, QPCI_DEVFN(0x1f, 0x00));
+    g_assert(d->dev != NULL);
+
+    /* map PCI-to-LPC bridge interface BAR */
+    d->lpc_base = qpci_iomap(d->dev, 0, NULL);
+
+    qpci_device_enable(d->dev);
+
+    g_assert(d->lpc_base != NULL);
+
+    /* set ACPI PM I/O space base address */
+    qpci_config_writel(d->dev, (uintptr_t)d->lpc_base + ICH9_LPC_PMBASE,
+                       PM_IO_BASE_ADDR | 0x1);
+    /* enable ACPI I/O */
+    qpci_config_writeb(d->dev, (uintptr_t)d->lpc_base + ICH9_LPC_ACPI_CTRL,
+                       0x80);
+    /* set Root Complex BAR */
+    qpci_config_writel(d->dev, (uintptr_t)d->lpc_base + ICH9_LPC_RCBA,
+                       ICH9_RCBA_BASE_ADDR | 0x1);
+
+    d->tco_io_base = (void *)((uintptr_t)PM_IO_BASE_ADDR + 0x60);
+}
+
+static void stop_tco(const TestData *d)
+{
+    uint32_t val;
+
+    val = qpci_io_readw(d->dev, d->tco_io_base + TCO1_CNT);
+    val |= TCO_TMR_HLT;
+    qpci_io_writew(d->dev, d->tco_io_base + TCO1_CNT, val);
+}
+
+static void start_tco(const TestData *d)
+{
+    uint32_t val;
+
+    val = qpci_io_readw(d->dev, d->tco_io_base + TCO1_CNT);
+    val &= ~TCO_TMR_HLT;
+    qpci_io_writew(d->dev, d->tco_io_base + TCO1_CNT, val);
+}
+
+static void load_tco(const TestData *d)
+{
+    qpci_io_writew(d->dev, d->tco_io_base + TCO_RLD, 4);
+}
+
+static void set_tco_timeout(const TestData *d, uint16_t ticks)
+{
+    qpci_io_writew(d->dev, d->tco_io_base + TCO_TMR, ticks);
+}
+
+static void clear_tco_status(const TestData *d)
+{
+    qpci_io_writew(d->dev, d->tco_io_base + TCO1_STS, 0x0008);
+    qpci_io_writew(d->dev, d->tco_io_base + TCO2_STS, 0x0002);
+    qpci_io_writew(d->dev, d->tco_io_base + TCO2_STS, 0x0004);
+}
+
+static void reset_on_second_timeout(bool enable)
+{
+    uint32_t val;
+
+    val = readl(ICH9_RCBA_BASE_ADDR + ICH9_LPC_RCBA_GCS);
+    if (enable) {
+        val &= ~ICH9_LPC_RCBA_GCS_NO_REBOOT;
+    } else {
+        val |= ICH9_LPC_RCBA_GCS_NO_REBOOT;
+    }
+    writel(ICH9_RCBA_BASE_ADDR + ICH9_LPC_RCBA_GCS, val);
+}
+
+static void test_tco_defaults(void)
+{
+    TestData d;
+
+    d.args = NULL;
+    test_init(&d);
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO_RLD), ==,
+                    TCO_RLD_DEFAULT);
+    /* TCO_DAT_IN & TCO_DAT_OUT */
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO_DAT_IN), ==,
+                    (TCO_DAT_OUT_DEFAULT << 8) | TCO_DAT_IN_DEFAULT);
+    /* TCO1_STS & TCO2_STS */
+    g_assert_cmpint(qpci_io_readl(d.dev, d.tco_io_base + TCO1_STS), ==,
+                    (TCO2_STS_DEFAULT << 16) | TCO1_STS_DEFAULT);
+    /* TCO1_CNT & TCO2_CNT */
+    g_assert_cmpint(qpci_io_readl(d.dev, d.tco_io_base + TCO1_CNT), ==,
+                    (TCO2_CNT_DEFAULT << 16) | TCO1_CNT_DEFAULT);
+    /* TCO_MESSAGE1 & TCO_MESSAGE2 */
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO_MESSAGE1), ==,
+                    (TCO_MESSAGE2_DEFAULT << 8) | TCO_MESSAGE1_DEFAULT);
+    g_assert_cmpint(qpci_io_readb(d.dev, d.tco_io_base + TCO_WDCNT), ==,
+                    TCO_WDCNT_DEFAULT);
+    g_assert_cmpint(qpci_io_readb(d.dev, d.tco_io_base + SW_IRQ_GEN), ==,
+                    SW_IRQ_GEN_DEFAULT);
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO_TMR), ==,
+                    TCO_TMR_DEFAULT);
+    qtest_end();
+}
+
+static void test_tco_timeout(void)
+{
+    TestData d;
+    const uint16_t ticks = TCO_SECS_TO_TICKS(4);
+    uint32_t val;
+    int ret;
+
+    d.args = NULL;
+    test_init(&d);
+
+    stop_tco(&d);
+    clear_tco_status(&d);
+    reset_on_second_timeout(false);
+    set_tco_timeout(&d, ticks);
+    load_tco(&d);
+    start_tco(&d);
+    clock_step(ticks * TCO_TICK_NSEC);
+
+    /* test first timeout */
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & TCO_TIMEOUT ? 1 : 0;
+    g_assert(ret == 1);
+
+    /* test clearing timeout bit */
+    val |= TCO_TIMEOUT;
+    qpci_io_writew(d.dev, d.tco_io_base + TCO1_STS, val);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & TCO_TIMEOUT ? 1 : 0;
+    g_assert(ret == 0);
+
+    /* test second timeout */
+    clock_step(ticks * TCO_TICK_NSEC);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & TCO_TIMEOUT ? 1 : 0;
+    g_assert(ret == 1);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO2_STS);
+    ret = val & TCO_SECOND_TO_STS ? 1 : 0;
+    g_assert(ret == 1);
+
+    stop_tco(&d);
+    qtest_end();
+}
+
+static void test_tco_max_timeout(void)
+{
+    TestData d;
+    const uint16_t ticks = 0xffff;
+    uint32_t val;
+    int ret;
+
+    d.args = NULL;
+    test_init(&d);
+
+    stop_tco(&d);
+    clear_tco_status(&d);
+    reset_on_second_timeout(false);
+    set_tco_timeout(&d, ticks);
+    load_tco(&d);
+    start_tco(&d);
+    clock_step(((ticks & TCO_TMR_MASK) - 1) * TCO_TICK_NSEC);
+
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO_RLD);
+    g_assert_cmpint(val & TCO_RLD_MASK, ==, 1);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & TCO_TIMEOUT ? 1 : 0;
+    g_assert(ret == 0);
+    clock_step(TCO_TICK_NSEC);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & TCO_TIMEOUT ? 1 : 0;
+    g_assert(ret == 1);
+
+    stop_tco(&d);
+    qtest_end();
+}
+
+static QDict *get_watchdog_action(void)
+{
+    QDict *ev = qmp("");
+    QDict *data;
+    g_assert(!strcmp(qdict_get_str(ev, "event"), "WATCHDOG"));
+
+    data = qdict_get_qdict(ev, "data");
+    QINCREF(data);
+    QDECREF(ev);
+    return data;
+}
+
+static void test_tco_second_timeout_pause(void)
+{
+    TestData td;
+    const uint16_t ticks = TCO_SECS_TO_TICKS(32);
+    QDict *ad;
+
+    td.args = "-watchdog-action pause";
+    test_init(&td);
+
+    stop_tco(&td);
+    clear_tco_status(&td);
+    reset_on_second_timeout(true);
+    set_tco_timeout(&td, TCO_SECS_TO_TICKS(16));
+    load_tco(&td);
+    start_tco(&td);
+    clock_step(ticks * TCO_TICK_NSEC * 2);
+    ad = get_watchdog_action();
+    g_assert(!strcmp(qdict_get_str(ad, "action"), "pause"));
+    QDECREF(ad);
+
+    stop_tco(&td);
+    qtest_end();
+}
+
+static void test_tco_second_timeout_reset(void)
+{
+    TestData td;
+    const uint16_t ticks = TCO_SECS_TO_TICKS(16);
+    QDict *ad;
+
+    td.args = "-watchdog-action reset";
+    test_init(&td);
+
+    stop_tco(&td);
+    clear_tco_status(&td);
+    reset_on_second_timeout(true);
+    set_tco_timeout(&td, TCO_SECS_TO_TICKS(16));
+    load_tco(&td);
+    start_tco(&td);
+    clock_step(ticks * TCO_TICK_NSEC * 2);
+    ad = get_watchdog_action();
+    g_assert(!strcmp(qdict_get_str(ad, "action"), "reset"));
+    QDECREF(ad);
+
+    stop_tco(&td);
+    qtest_end();
+}
+
+static void test_tco_second_timeout_shutdown(void)
+{
+    TestData td;
+    const uint16_t ticks = TCO_SECS_TO_TICKS(128);
+    QDict *ad;
+
+    td.args = "-watchdog-action shutdown";
+    test_init(&td);
+
+    stop_tco(&td);
+    clear_tco_status(&td);
+    reset_on_second_timeout(true);
+    set_tco_timeout(&td, ticks);
+    load_tco(&td);
+    start_tco(&td);
+    clock_step(ticks * TCO_TICK_NSEC * 2);
+    ad = get_watchdog_action();
+    g_assert(!strcmp(qdict_get_str(ad, "action"), "shutdown"));
+    QDECREF(ad);
+
+    stop_tco(&td);
+    qtest_end();
+}
+
+static void test_tco_second_timeout_none(void)
+{
+    TestData td;
+    const uint16_t ticks = TCO_SECS_TO_TICKS(256);
+    QDict *ad;
+
+    td.args = "-watchdog-action none";
+    test_init(&td);
+
+    stop_tco(&td);
+    clear_tco_status(&td);
+    reset_on_second_timeout(true);
+    set_tco_timeout(&td, ticks);
+    load_tco(&td);
+    start_tco(&td);
+    clock_step(ticks * TCO_TICK_NSEC * 2);
+    ad = get_watchdog_action();
+    g_assert(!strcmp(qdict_get_str(ad, "action"), "none"));
+    QDECREF(ad);
+
+    stop_tco(&td);
+    qtest_end();
+}
+
+static void test_tco_ticks_counter(void)
+{
+    TestData d;
+    uint16_t ticks = TCO_SECS_TO_TICKS(8);
+    uint16_t rld;
+
+    d.args = NULL;
+    test_init(&d);
+
+    stop_tco(&d);
+    clear_tco_status(&d);
+    reset_on_second_timeout(false);
+    set_tco_timeout(&d, ticks);
+    load_tco(&d);
+    start_tco(&d);
+
+    do {
+        rld = qpci_io_readw(d.dev, d.tco_io_base + TCO_RLD) & TCO_RLD_MASK;
+        g_assert_cmpint(rld, ==, ticks);
+        clock_step(TCO_TICK_NSEC);
+        ticks--;
+    } while (!(qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS) & TCO_TIMEOUT));
+
+    stop_tco(&d);
+    qtest_end();
+}
+
+static void test_tco1_control_bits(void)
+{
+    TestData d;
+    uint16_t val;
+
+    d.args = NULL;
+    test_init(&d);
+
+    val = TCO_LOCK;
+    qpci_io_writew(d.dev, d.tco_io_base + TCO1_CNT, val);
+    val &= ~TCO_LOCK;
+    qpci_io_writew(d.dev, d.tco_io_base + TCO1_CNT, val);
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO1_CNT), ==,
+                    TCO_LOCK);
+    qtest_end();
+}
+
+static void test_tco1_status_bits(void)
+{
+    TestData d;
+    uint16_t ticks = 8;
+    uint16_t val;
+    int ret;
+
+    d.args = NULL;
+    test_init(&d);
+
+    stop_tco(&d);
+    clear_tco_status(&d);
+    reset_on_second_timeout(false);
+    set_tco_timeout(&d, ticks);
+    load_tco(&d);
+    start_tco(&d);
+    clock_step(ticks * TCO_TICK_NSEC);
+
+    qpci_io_writeb(d.dev, d.tco_io_base + TCO_DAT_IN, 0);
+    qpci_io_writeb(d.dev, d.tco_io_base + TCO_DAT_OUT, 0);
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS);
+    ret = val & (TCO_TIMEOUT | SW_TCO_SMI | TCO_INT_STS) ? 1 : 0;
+    g_assert(ret == 1);
+    qpci_io_writew(d.dev, d.tco_io_base + TCO1_STS, val);
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO1_STS), ==, 0);
+    qtest_end();
+}
+
+static void test_tco2_status_bits(void)
+{
+    TestData d;
+    uint16_t ticks = 8;
+    uint16_t val;
+    int ret;
+
+    d.args = "-watchdog-action none";
+    test_init(&d);
+
+    stop_tco(&d);
+    clear_tco_status(&d);
+    reset_on_second_timeout(true);
+    set_tco_timeout(&d, ticks);
+    load_tco(&d);
+    start_tco(&d);
+    clock_step(ticks * TCO_TICK_NSEC * 2);
+
+    val = qpci_io_readw(d.dev, d.tco_io_base + TCO2_STS);
+    ret = val & (TCO_SECOND_TO_STS | TCO_BOOT_STS) ? 1 : 0;
+    g_assert(ret == 1);
+    qpci_io_writew(d.dev, d.tco_io_base + TCO2_STS, val);
+    g_assert_cmpint(qpci_io_readw(d.dev, d.tco_io_base + TCO2_STS), ==, 0);
+    qtest_end();
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_add_func("tco/defaults", test_tco_defaults);
+    qtest_add_func("tco/timeout/no_action", test_tco_timeout);
+    qtest_add_func("tco/timeout/no_action/max", test_tco_max_timeout);
+    qtest_add_func("tco/second_timeout/pause", test_tco_second_timeout_pause);
+    qtest_add_func("tco/second_timeout/reset", test_tco_second_timeout_reset);
+    qtest_add_func("tco/second_timeout/shutdown",
+                   test_tco_second_timeout_shutdown);
+    qtest_add_func("tco/second_timeout/none", test_tco_second_timeout_none);
+    qtest_add_func("tco/counter", test_tco_ticks_counter);
+    qtest_add_func("tco/tco1_control/bits", test_tco1_control_bits);
+    qtest_add_func("tco/tco1_status/bits", test_tco1_status_bits);
+    qtest_add_func("tco/tco2_status/bits", test_tco2_status_bits);
+    return g_test_run();
+}
