git: 2b74ff5fceb6 - main - ichwd: introduce i6300esbwd watch dog driver
Date: Mon, 25 Aug 2025 15:45:52 UTC
The branch main has been updated by aokblast:
URL: https://cgit.FreeBSD.org/src/commit/?id=2b74ff5fceb6623f6114ce39baee9f6ec5f79277
commit 2b74ff5fceb6623f6114ce39baee9f6ec5f79277
Author: ShengYi Hung <aokblast@FreeBSD.org>
AuthorDate: 2025-08-22 14:55:45 +0000
Commit: ShengYi Hung <aokblast@FreeBSD.org>
CommitDate: 2025-08-25 15:45:24 +0000
ichwd: introduce i6300esbwd watch dog driver
The intel 6300ESB watchdog is a special ICH-based watchdog device with a
different interface.
QEMU implements this watchdog for x86 systems.
This change enables watchdog mode (rather than free-running mode) and
introduces 1 sysctl:
- hw.i6300esbwd.0.locked: locks the watchdog register after the event is
triggered, preventing it from being disabled until a hard reset.
This feature has been tested on a Vultr AMD guest machine and local qemu
machine.
PR: 259673
Approved by: markj (mentor), lwhsu (mentor)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D52049
---
sys/conf/files.x86 | 1 +
sys/dev/ichwd/i6300esbwd.c | 245 +++++++++++++++++++++++++++++++++++++++++++++
sys/dev/ichwd/i6300esbwd.h | 46 +++++++++
sys/dev/ichwd/ichwd.c | 2 +-
sys/dev/ichwd/ichwd.h | 3 +-
sys/modules/ichwd/Makefile | 2 +-
6 files changed, 296 insertions(+), 3 deletions(-)
diff --git a/sys/conf/files.x86 b/sys/conf/files.x86
index 9976e9cfec5d..953da7dd1284 100644
--- a/sys/conf/files.x86
+++ b/sys/conf/files.x86
@@ -146,6 +146,7 @@ dev/hyperv/vmbus/vmbus_et.c optional hyperv
dev/hyperv/vmbus/vmbus_if.m optional hyperv
dev/hyperv/vmbus/vmbus_res.c optional hyperv
dev/hyperv/vmbus/vmbus_xact.c optional hyperv
+dev/ichwd/i6300esbwd.c optional ichwd
dev/ichwd/ichwd.c optional ichwd
dev/imcsmb/imcsmb.c optional imcsmb
dev/imcsmb/imcsmb_pci.c optional imcsmb pci
diff --git a/sys/dev/ichwd/i6300esbwd.c b/sys/dev/ichwd/i6300esbwd.c
new file mode 100644
index 000000000000..d95aeb53c3f5
--- /dev/null
+++ b/sys/dev/ichwd/i6300esbwd.c
@@ -0,0 +1,245 @@
+/*
+ * Copyright (c) 2025 The FreeBSD Foundation
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+/*
+ * Reference: Intel 6300ESB Controller Hub Datasheet Section 16
+ */
+
+#include <sys/param.h>
+#include <sys/eventhandler.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/sysctl.h>
+#include <sys/errno.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <machine/bus.h>
+#include <sys/rman.h>
+#include <machine/resource.h>
+#include <sys/watchdog.h>
+
+#include <dev/pci/pcireg.h>
+
+#include <dev/ichwd/ichwd.h>
+#include <dev/ichwd/i6300esbwd.h>
+
+#include <x86/pci_cfgreg.h>
+#include <dev/pci/pcivar.h>
+#include <dev/pci/pci_private.h>
+
+struct i6300esbwd_softc {
+ device_t dev;
+ int res_id;
+ struct resource *res;
+ eventhandler_tag ev_tag;
+ bool locked;
+};
+
+static const struct i6300esbwd_pci_id {
+ uint16_t id;
+ const char *name;
+} i6300esbwd_pci_devices[] = {
+ { DEVICEID_6300ESB_2, "6300ESB Watchdog Timer" },
+};
+
+static uint16_t
+i6300esbwd_cfg_read(struct i6300esbwd_softc *sc)
+{
+ return (pci_read_config(sc->dev, WDT_CONFIG_REG, 2));
+}
+
+static void
+i6300esbwd_cfg_write(struct i6300esbwd_softc *sc, uint16_t val)
+{
+ pci_write_config(sc->dev, WDT_CONFIG_REG, val, 2);
+}
+
+static uint8_t
+i6300esbwd_lock_read(struct i6300esbwd_softc *sc)
+{
+ return (pci_read_config(sc->dev, WDT_LOCK_REG, 1));
+}
+
+static void
+i6300esbwd_lock_write(struct i6300esbwd_softc *sc, uint8_t val)
+{
+ pci_write_config(sc->dev, WDT_LOCK_REG, val, 1);
+}
+
+/*
+ * According to Intel 6300ESB I/O Controller Hub Datasheet 16.5.2,
+ * the resource should be unlocked before modifing any registers.
+ * The way to unlock is by write 0x80, 0x86 to the reload register.
+ */
+static void
+i6300esbwd_unlock_res(struct i6300esbwd_softc *sc)
+{
+ bus_write_2(sc->res, WDT_RELOAD_REG, WDT_UNLOCK_SEQ_1_VAL);
+ bus_write_2(sc->res, WDT_RELOAD_REG, WDT_UNLOCK_SEQ_2_VAL);
+}
+
+static int
+i6300esbwd_sysctl_locked(SYSCTL_HANDLER_ARGS)
+{
+ struct i6300esbwd_softc *sc = (struct i6300esbwd_softc *)arg1;
+ int error;
+ int result;
+
+ result = sc->locked;
+ error = sysctl_handle_int(oidp, &result, 0, req);
+
+ if (error || !req->newptr)
+ return (error);
+
+ if (result == 1 && !sc->locked) {
+ i6300esbwd_lock_write(sc, i6300esbwd_lock_read(sc) | WDT_LOCK);
+ sc->locked = true;
+ }
+
+ return (0);
+}
+
+static void
+i6300esbwd_event(void *arg, unsigned int cmd, int *error)
+{
+ struct i6300esbwd_softc *sc = arg;
+ uint32_t timeout;
+ uint16_t regval;
+
+ cmd &= WD_INTERVAL;
+ if (cmd != 0 &&
+ (cmd < WD_TO_1MS || (cmd - WD_TO_1MS) >= WDT_PRELOAD_BIT)) {
+ *error = EINVAL;
+ return;
+ }
+ timeout = 1 << (cmd - WD_TO_1MS);
+
+ /* reset the timer to prevent timeout a timeout is about to occur */
+ i6300esbwd_unlock_res(sc);
+ bus_write_2(sc->res, WDT_RELOAD_REG, WDT_RELOAD);
+
+ if (!cmd) {
+ /*
+ * when the lock is enabled, we are unable to overwrite LOCK
+ * register
+ */
+ if (sc->locked)
+ *error = EPERM;
+ else
+ i6300esbwd_lock_write(sc,
+ i6300esbwd_lock_read(sc) & ~WDT_ENABLE);
+ return;
+ }
+
+ i6300esbwd_unlock_res(sc);
+ bus_write_4(sc->res, WDT_PRELOAD_1_REG, timeout);
+
+ i6300esbwd_unlock_res(sc);
+ bus_write_4(sc->res, WDT_PRELOAD_2_REG, timeout);
+
+ i6300esbwd_unlock_res(sc);
+ bus_write_2(sc->res, WDT_RELOAD_REG, WDT_RELOAD);
+
+ if (!sc->locked) {
+ i6300esbwd_lock_write(sc, WDT_ENABLE);
+ regval = i6300esbwd_lock_read(sc);
+ sc->locked = regval & WDT_LOCK;
+ }
+}
+
+static int
+i6300esbwd_probe(device_t dev)
+{
+ const struct i6300esbwd_pci_id *pci_id;
+ uint16_t pci_dev_id;
+ int err = ENXIO;
+
+ if (pci_get_vendor(dev) != VENDORID_INTEL)
+ goto end;
+
+ pci_dev_id = pci_get_device(dev);
+ for (pci_id = i6300esbwd_pci_devices;
+ pci_id < i6300esbwd_pci_devices + nitems(i6300esbwd_pci_devices);
+ ++pci_id) {
+ if (pci_id->id == pci_dev_id) {
+ device_set_desc(dev, pci_id->name);
+ err = BUS_PROBE_DEFAULT;
+ break;
+ }
+ }
+
+end:
+ return (err);
+}
+
+static int
+i6300esbwd_attach(device_t dev)
+{
+ struct i6300esbwd_softc *sc = device_get_softc(dev);
+ uint16_t regval;
+
+ sc->dev = dev;
+ sc->res_id = PCIR_BAR(0);
+ sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->res_id,
+ RF_ACTIVE);
+ if (sc->res == NULL) {
+ device_printf(dev, "unable to map memory region\n");
+ return (ENXIO);
+ }
+
+ i6300esbwd_cfg_write(sc, WDT_INT_TYPE_DISABLED_VAL);
+ regval = i6300esbwd_lock_read(sc);
+ if (regval & WDT_LOCK)
+ sc->locked = true;
+ else {
+ sc->locked = false;
+ i6300esbwd_lock_write(sc, WDT_TOUT_CNF_WT_MODE);
+ }
+
+ i6300esbwd_unlock_res(sc);
+ bus_write_2(sc->res, WDT_RELOAD_REG, WDT_RELOAD | WDT_TIMEOUT);
+
+ sc->ev_tag = EVENTHANDLER_REGISTER(watchdog_list, i6300esbwd_event, sc,
+ 0);
+
+ SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
+ SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "locked",
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
+ i6300esbwd_sysctl_locked, "I",
+ "Lock the timer so that we cannot disable it");
+
+ return (0);
+}
+
+static int
+i6300esbwd_detach(device_t dev)
+{
+ struct i6300esbwd_softc *sc = device_get_softc(dev);
+
+ if (sc->ev_tag)
+ EVENTHANDLER_DEREGISTER(watchdog_list, sc->ev_tag);
+
+ if (sc->res)
+ bus_release_resource(dev, SYS_RES_MEMORY, sc->res_id, sc->res);
+
+ return (0);
+}
+
+static device_method_t i6300esbwd_methods[] = {
+ DEVMETHOD(device_probe, i6300esbwd_probe),
+ DEVMETHOD(device_attach, i6300esbwd_attach),
+ DEVMETHOD(device_detach, i6300esbwd_detach),
+ DEVMETHOD(device_shutdown, i6300esbwd_detach),
+ DEVMETHOD_END
+};
+
+static driver_t i6300esbwd_driver = {
+ "i6300esbwd",
+ i6300esbwd_methods,
+ sizeof(struct i6300esbwd_softc),
+};
+
+DRIVER_MODULE(i6300esbwd, pci, i6300esbwd_driver, NULL, NULL);
diff --git a/sys/dev/ichwd/i6300esbwd.h b/sys/dev/ichwd/i6300esbwd.h
new file mode 100644
index 000000000000..39ed5d5a84f6
--- /dev/null
+++ b/sys/dev/ichwd/i6300esbwd.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2025 The FreeBSD Foundation
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#ifndef _I6300ESBWD_H_
+#define _I6300ESBWD_H_
+
+#define WDT_CONFIG_REG 0x60
+#define WDT_LOCK_REG 0x68
+
+#define WDT_PRELOAD_1_REG 0x00
+#define WDT_PRELOAD_2_REG 0x04
+#define WDT_INTR_REG 0x08
+#define WDT_RELOAD_REG 0x0C
+
+/* For config register */
+#define WDT_OUTPUT_EN (0x1 << 5)
+#define WDT_PRE_SEL (0x1 << 2)
+#define WDT_INT_TYPE_BITS (0x3)
+#define WDT_INT_TYPE_IRQ_VAL (0x0)
+#define WDT_INT_TYPE_RES_VAL (0x1)
+#define WDT_INT_TYPE_SMI_VAL (0x2)
+#define WDT_INT_TYPE_DISABLED_VAL (0x3)
+
+/* For lock register */
+#define WDT_TOUT_CNF_WT_MODE (0x0 << 2)
+#define WDT_TOUT_CNF_FR_MODE (0x1 << 2)
+#define WDT_ENABLE (0x02)
+#define WDT_LOCK (0x01)
+
+/* For preload 1/2 registers */
+#define WDT_PRELOAD_BIT 20
+#define WDT_PRELOAD_BITS ((0x1 << WDT_PRELOAD_BIT) - 1)
+
+/* For interrupt register */
+#define WDT_INTR_ACT (0x01 << 0)
+
+/* For reload register */
+#define WDT_TIMEOUT (0x01 << 9)
+#define WDT_RELOAD (0x01 << 8)
+#define WDT_UNLOCK_SEQ_1_VAL 0x80
+#define WDT_UNLOCK_SEQ_2_VAL 0x86
+
+#endif /* _I6300ESBWD_H_ */
diff --git a/sys/dev/ichwd/ichwd.c b/sys/dev/ichwd/ichwd.c
index cade2cc4fb45..5481553cc175 100644
--- a/sys/dev/ichwd/ichwd.c
+++ b/sys/dev/ichwd/ichwd.c
@@ -90,7 +90,7 @@ static struct ichwd_device ichwd_devices[] = {
{ DEVICEID_82801E, "Intel 82801E watchdog timer", 5, 1 },
{ DEVICEID_82801EB, "Intel 82801EB watchdog timer", 5, 1 },
{ DEVICEID_82801EBR, "Intel 82801EB/ER watchdog timer", 5, 1 },
- { DEVICEID_6300ESB, "Intel 6300ESB watchdog timer", 5, 1 },
+ { DEVICEID_6300ESB_1, "Intel 6300ESB watchdog timer", 5, 1 },
{ DEVICEID_82801FBR, "Intel 82801FB/FR watchdog timer", 6, 2 },
{ DEVICEID_ICH6M, "Intel ICH6M watchdog timer", 6, 2 },
{ DEVICEID_ICH6W, "Intel ICH6W watchdog timer", 6, 2 },
diff --git a/sys/dev/ichwd/ichwd.h b/sys/dev/ichwd/ichwd.h
index 90fda08b74c1..72d0ca1cd6aa 100644
--- a/sys/dev/ichwd/ichwd.h
+++ b/sys/dev/ichwd/ichwd.h
@@ -151,7 +151,8 @@ struct ichwd_softc {
#define DEVICEID_82801E 0x2450
#define DEVICEID_82801EB 0x24dc
#define DEVICEID_82801EBR 0x24d0
-#define DEVICEID_6300ESB 0x25a1
+#define DEVICEID_6300ESB_1 0x25a1
+#define DEVICEID_6300ESB_2 0x25ab
#define DEVICEID_82801FBR 0x2640
#define DEVICEID_ICH6M 0x2641
#define DEVICEID_ICH6W 0x2642
diff --git a/sys/modules/ichwd/Makefile b/sys/modules/ichwd/Makefile
index 3c3bbc37eff5..27b4c38437ff 100644
--- a/sys/modules/ichwd/Makefile
+++ b/sys/modules/ichwd/Makefile
@@ -1,6 +1,6 @@
.PATH: ${SRCTOP}/sys/dev/ichwd
KMOD= ichwd
-SRCS= ichwd.c device_if.h bus_if.h pci_if.h isa_if.h
+SRCS= i6300esbwd.c ichwd.c device_if.h bus_if.h pci_if.h isa_if.h
.include <bsd.kmod.mk>