ich9: add TCO interface emulation

This interface provides some registers within a 32-byte range and can be
acessed through PCI-to-LPC bridge interface (PMBASE + 0x60).

It's commonly used as a watchdog timer to detect system lockups through
SMIs that are generated -- if TCO_EN bit is set -- on every timeout. If
NO_REBOOT bit is not set in GCS (General Control and Status register),
the system will be resetted upon second timeout if TCO_RLD register
wasn't previously written to prevent timeout.

This patch adds support to TCO watchdog logic and few other features
like mapping NMIs to SMIs (NMI2SMI_EN bit), system intruder detection,
etc. are not implemented yet.

Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

3 files changed, 321 insertions, 2 deletions

diff --git a/hw/acpi/Makefile.objs b/hw/acpi/Makefile.objs
index 640b15ddc2..7d3230c2a5 100644
--- a/hw/acpi/Makefile.objs
+++ b/hw/acpi/Makefile.objs
@@ -1,5 +1,5 @@
 common-obj-$(CONFIG_ACPI_X86) += core.o piix4.o pcihp.o
-common-obj-$(CONFIG_ACPI_X86_ICH) += ich9.o
+common-obj-$(CONFIG_ACPI_X86_ICH) += ich9.o tco.o
 common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu_hotplug.o
 common-obj-$(CONFIG_ACPI_MEMORY_HOTPLUG) += memory_hotplug.o
 common-obj-$(CONFIG_ACPI) += acpi_interface.o
diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index f4dc7a84be..5fb7a879d6 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -30,6 +30,7 @@
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "hw/acpi/acpi.h"
+#include "hw/acpi/tco.h"
 #include "sysemu/kvm.h"
 #include "exec/address-spaces.h"
 
@@ -92,8 +93,16 @@ static void ich9_smi_writel(void *opaque, hwaddr addr, uint64_t val,
                             unsigned width)
 {
     ICH9LPCPMRegs *pm = opaque;
+    TCOIORegs *tr = &pm->tco_regs;
+    uint64_t tco_en;
+
     switch (addr) {
     case 0:
+        tco_en = pm->smi_en & ICH9_PMIO_SMI_EN_TCO_EN;
+        /* once TCO_LOCK bit is set, TCO_EN bit cannot be overwritten */
+        if (tr->tco.cnt1 & TCO_LOCK) {
+            val = (val & ~ICH9_PMIO_SMI_EN_TCO_EN) | tco_en;
+        }
         pm->smi_en &= ~pm->smi_en_wmask;
         pm->smi_en |= (val & pm->smi_en_wmask);
         break;
@@ -159,6 +168,25 @@ static const VMStateDescription vmstate_memhp_state = {
     }
 };
 
+static bool vmstate_test_use_tco(void *opaque)
+{
+    ICH9LPCPMRegs *s = opaque;
+    return s->enable_tco;
+}
+
+static const VMStateDescription vmstate_tco_io_state = {
+    .name = "ich9_pm/tco",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .needed = vmstate_test_use_tco,
+    .fields      = (VMStateField[]) {
+        VMSTATE_STRUCT(tco_regs, ICH9LPCPMRegs, 1, vmstate_tco_io_sts,
+                       TCOIORegs),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_ich9_pm = {
     .name = "ich9_pm",
     .version_id = 1,
@@ -179,6 +207,10 @@ const VMStateDescription vmstate_ich9_pm = {
     .subsections = (const VMStateDescription*[]) {
         &vmstate_memhp_state,
         NULL
+    },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_tco_io_state,
+        NULL
     }
 };
 
@@ -209,7 +241,8 @@ static void pm_powerdown_req(Notifier *n, void *opaque)
     acpi_pm1_evt_power_down(&pm->acpi_regs);
 }
 
-void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm, bool smm_enabled,
+void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
+                  bool smm_enabled, bool enable_tco,
                   qemu_irq sci_irq)
 {
     memory_region_init(&pm->io, OBJECT(lpc_pci), "ich9-pm", ICH9_PMIO_SIZE);
@@ -232,6 +265,12 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm, bool smm_enabled,
     memory_region_add_subregion(&pm->io, ICH9_PMIO_SMI_EN, &pm->io_smi);
 
     pm->smm_enabled = smm_enabled;
+
+    pm->enable_tco = enable_tco;
+    if (pm->enable_tco) {
+        acpi_pm_tco_init(&pm->tco_regs, &pm->io);
+    }
+
     pm->irq = sci_irq;
     qemu_register_reset(pm_reset, pm);
     pm->powerdown_notifier.notify = pm_powerdown_req;
@@ -352,6 +391,18 @@ out:
     error_propagate(errp, local_err);
 }
 
+static bool ich9_pm_get_enable_tco(Object *obj, Error **errp)
+{
+    ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
+    return s->pm.enable_tco;
+}
+
+static void ich9_pm_set_enable_tco(Object *obj, bool value, Error **errp)
+{
+    ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
+    s->pm.enable_tco = value;
+}
+
 void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp)
 {
     static const uint32_t gpe0_len = ICH9_PMIO_GPE0_LEN;
@@ -383,6 +434,10 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp)
                         ich9_pm_get_s4_val,
                         ich9_pm_set_s4_val,
                         NULL, pm, NULL);
+    object_property_add_bool(obj, ACPI_PM_PROP_TCO_ENABLED,
+                             ich9_pm_get_enable_tco,
+                             ich9_pm_set_enable_tco,
+                             NULL);
 }
 
 void ich9_pm_device_plug_cb(ICH9LPCPMRegs *pm, DeviceState *dev, Error **errp)
diff --git a/hw/acpi/tco.c b/hw/acpi/tco.c
new file mode 100644
index 0000000000..1794a54545
--- /dev/null
+++ b/hw/acpi/tco.c
@@ -0,0 +1,264 @@
+/*
+ * QEMU ICH9 TCO emulation
+ *
+ * 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 "qemu-common.h"
+#include "sysemu/watchdog.h"
+#include "hw/i386/ich9.h"
+
+#include "hw/acpi/tco.h"
+
+//#define DEBUG
+
+#ifdef DEBUG
+#define TCO_DEBUG(fmt, ...)                                     \
+    do {                                                        \
+        fprintf(stderr, "%s "fmt, __func__, ## __VA_ARGS__);    \
+    } while (0)
+#else
+#define TCO_DEBUG(fmt, ...) do { } while (0)
+#endif
+
+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,
+};
+
+static inline void tco_timer_reload(TCOIORegs *tr)
+{
+    tr->expire_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+        ((int64_t)(tr->tco.tmr & TCO_TMR_MASK) * TCO_TICK_NSEC);
+    timer_mod(tr->tco_timer, tr->expire_time);
+}
+
+static inline void tco_timer_stop(TCOIORegs *tr)
+{
+    tr->expire_time = -1;
+}
+
+static void tco_timer_expired(void *opaque)
+{
+    TCOIORegs *tr = opaque;
+    ICH9LPCPMRegs *pm = container_of(tr, ICH9LPCPMRegs, tco_regs);
+    ICH9LPCState *lpc = container_of(pm, ICH9LPCState, pm);
+    uint32_t gcs = pci_get_long(lpc->chip_config + ICH9_CC_GCS);
+
+    tr->tco.rld = 0;
+    tr->tco.sts1 |= TCO_TIMEOUT;
+    if (++tr->timeouts_no == 2) {
+        tr->tco.sts2 |= TCO_SECOND_TO_STS;
+        tr->tco.sts2 |= TCO_BOOT_STS;
+        tr->timeouts_no = 0;
+
+        if (!(gcs & ICH9_CC_GCS_NO_REBOOT)) {
+            watchdog_perform_action();
+            tco_timer_stop(tr);
+            return;
+        }
+    }
+
+    if (pm->smi_en & ICH9_PMIO_SMI_EN_TCO_EN) {
+        ich9_generate_smi();
+    } else {
+        ich9_generate_nmi();
+    }
+    tr->tco.rld = tr->tco.tmr;
+    tco_timer_reload(tr);
+}
+
+/* NOTE: values of 0 or 1 will be ignored by ICH */
+static inline int can_start_tco_timer(TCOIORegs *tr)
+{
+    return !(tr->tco.cnt1 & TCO_TMR_HLT) && tr->tco.tmr > 1;
+}
+
+static uint32_t tco_ioport_readw(TCOIORegs *tr, uint32_t addr)
+{
+    uint16_t rld;
+
+    switch (addr) {
+    case TCO_RLD:
+        if (tr->expire_time != -1) {
+            int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+            int64_t elapsed = (tr->expire_time - now) / TCO_TICK_NSEC;
+            rld = (uint16_t)elapsed | (tr->tco.rld & ~TCO_RLD_MASK);
+        } else {
+            rld = tr->tco.rld;
+        }
+        return rld;
+    case TCO_DAT_IN:
+        return tr->tco.din;
+    case TCO_DAT_OUT:
+        return tr->tco.dout;
+    case TCO1_STS:
+        return tr->tco.sts1;
+    case TCO2_STS:
+        return tr->tco.sts2;
+    case TCO1_CNT:
+        return tr->tco.cnt1;
+    case TCO2_CNT:
+        return tr->tco.cnt2;
+    case TCO_MESSAGE1:
+        return tr->tco.msg1;
+    case TCO_MESSAGE2:
+        return tr->tco.msg2;
+    case TCO_WDCNT:
+        return tr->tco.wdcnt;
+    case TCO_TMR:
+        return tr->tco.tmr;
+    case SW_IRQ_GEN:
+        return tr->sw_irq_gen;
+    }
+    return 0;
+}
+
+static void tco_ioport_writew(TCOIORegs *tr, uint32_t addr, uint32_t val)
+{
+    switch (addr) {
+    case TCO_RLD:
+        tr->timeouts_no = 0;
+        if (can_start_tco_timer(tr)) {
+            tr->tco.rld = tr->tco.tmr;
+            tco_timer_reload(tr);
+        } else {
+            tr->tco.rld = val;
+        }
+        break;
+    case TCO_DAT_IN:
+        tr->tco.din = val;
+        tr->tco.sts1 |= SW_TCO_SMI;
+        ich9_generate_smi();
+        break;
+    case TCO_DAT_OUT:
+        tr->tco.dout = val;
+        tr->tco.sts1 |= TCO_INT_STS;
+        /* TODO: cause an interrupt, as selected by the TCO_INT_SEL bits */
+        break;
+    case TCO1_STS:
+        tr->tco.sts1 = val & TCO1_STS_MASK;
+        break;
+    case TCO2_STS:
+        tr->tco.sts2 = val & TCO2_STS_MASK;
+        break;
+    case TCO1_CNT:
+        val &= TCO1_CNT_MASK;
+        /*
+         * once TCO_LOCK bit is set, it can not be cleared by software. a reset
+         * is required to change this bit from 1 to 0 -- it defaults to 0.
+         */
+        tr->tco.cnt1 = val | (tr->tco.cnt1 & TCO_LOCK);
+        if (can_start_tco_timer(tr)) {
+            tr->tco.rld = tr->tco.tmr;
+            tco_timer_reload(tr);
+        } else {
+            tco_timer_stop(tr);
+        }
+        break;
+    case TCO2_CNT:
+        tr->tco.cnt2 = val;
+        break;
+    case TCO_MESSAGE1:
+        tr->tco.msg1 = val;
+        break;
+    case TCO_MESSAGE2:
+        tr->tco.msg2 = val;
+        break;
+    case TCO_WDCNT:
+        tr->tco.wdcnt = val;
+        break;
+    case TCO_TMR:
+        tr->tco.tmr = val;
+        break;
+    case SW_IRQ_GEN:
+        tr->sw_irq_gen = val;
+        break;
+    }
+}
+
+static uint64_t tco_io_readw(void *opaque, hwaddr addr, unsigned width)
+{
+    TCOIORegs *tr = opaque;
+    return tco_ioport_readw(tr, addr);
+}
+
+static void tco_io_writew(void *opaque, hwaddr addr, uint64_t val,
+                          unsigned width)
+{
+    TCOIORegs *tr = opaque;
+    tco_ioport_writew(tr, addr, val);
+}
+
+static const MemoryRegionOps tco_io_ops = {
+    .read = tco_io_readw,
+    .write = tco_io_writew,
+    .valid.min_access_size = 1,
+    .valid.max_access_size = 4,
+    .impl.min_access_size = 1,
+    .impl.max_access_size = 2,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+void acpi_pm_tco_init(TCOIORegs *tr, MemoryRegion *parent)
+{
+    *tr = (TCOIORegs) {
+        .tco = {
+            .rld      = TCO_RLD_DEFAULT,
+            .din      = TCO_DAT_IN_DEFAULT,
+            .dout     = TCO_DAT_OUT_DEFAULT,
+            .sts1     = TCO1_STS_DEFAULT,
+            .sts2     = TCO2_STS_DEFAULT,
+            .cnt1     = TCO1_CNT_DEFAULT,
+            .cnt2     = TCO2_CNT_DEFAULT,
+            .msg1     = TCO_MESSAGE1_DEFAULT,
+            .msg2     = TCO_MESSAGE2_DEFAULT,
+            .wdcnt    = TCO_WDCNT_DEFAULT,
+            .tmr      = TCO_TMR_DEFAULT,
+        },
+        .sw_irq_gen    = SW_IRQ_GEN_DEFAULT,
+        .tco_timer     = timer_new_ns(QEMU_CLOCK_VIRTUAL, tco_timer_expired, tr),
+        .expire_time   = -1,
+        .timeouts_no   = 0,
+    };
+    memory_region_init_io(&tr->io, memory_region_owner(parent),
+                          &tco_io_ops, tr, "sm-tco", ICH9_PMIO_TCO_LEN);
+    memory_region_add_subregion(parent, ICH9_PMIO_TCO_RLD, &tr->io);
+}
+
+const VMStateDescription vmstate_tco_io_sts = {
+    .name = "tco io device status",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT16(tco.rld, TCOIORegs),
+        VMSTATE_UINT8(tco.din, TCOIORegs),
+        VMSTATE_UINT8(tco.dout, TCOIORegs),
+        VMSTATE_UINT16(tco.sts1, TCOIORegs),
+        VMSTATE_UINT16(tco.sts2, TCOIORegs),
+        VMSTATE_UINT16(tco.cnt1, TCOIORegs),
+        VMSTATE_UINT16(tco.cnt2, TCOIORegs),
+        VMSTATE_UINT8(tco.msg1, TCOIORegs),
+        VMSTATE_UINT8(tco.msg2, TCOIORegs),
+        VMSTATE_UINT8(tco.wdcnt, TCOIORegs),
+        VMSTATE_UINT16(tco.tmr, TCOIORegs),
+        VMSTATE_UINT8(sw_irq_gen, TCOIORegs),
+        VMSTATE_TIMER_PTR(tco_timer, TCOIORegs),
+        VMSTATE_INT64(expire_time, TCOIORegs),
+        VMSTATE_UINT8(timeouts_no, TCOIORegs),
+        VMSTATE_END_OF_LIST()
+    }
+};