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>

1 files changed, 56 insertions, 1 deletions

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)