itwd(4): driver for watchdog function in ITE Super I/O chips

The chips are commonly named with "IT" prefix.

MFC after:	19 days

1 files changed, 236 insertions, 0 deletions

diff --git a/sys/dev/itwd/itwd.c b/sys/dev/itwd/itwd.c
new file mode 100644
index 000000000000..ee2bf0d20080
--- /dev/null
+++ b/sys/dev/itwd/itwd.c
@@ -0,0 +1,236 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Andriy Gapon
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/bus.h>
+#include <sys/eventhandler.h>
+#include <sys/module.h>
+#include <sys/rman.h>
+#include <sys/systm.h>
+#include <sys/watchdog.h>
+
+#include <dev/superio/superio.h>
+
+#include <machine/bus.h>
+#include <machine/resource.h>
+
+
+struct itwd_softc {
+	eventhandler_tag	wd_ev;
+	void			*intr_handle;
+	struct resource		*intr_res;
+	int			intr_rid;
+};
+
+static void
+wd_func(void *priv, u_int cmd, int *error)
+{
+	device_t dev = priv;
+	uint64_t timeout;
+	uint8_t val;
+
+
+	if (cmd != 0) {
+		cmd &= WD_INTERVAL;
+
+		/*
+		 * Convert the requested timeout to seconds.
+		 * If the timeout is smaller than the minimal supported value
+		 * then set it to the minimum.
+		 * TODO This hardware actually supports 64ms resolution
+		 * when bit 5 of 0x72 is set.  Switch to that resolution when
+		 * needed.
+		 */
+		if (cmd >= WD_TO_1SEC)
+			timeout = (uint64_t)1 << (cmd - WD_TO_1SEC);
+		else
+			timeout = 1;
+
+		/* TODO If timeout is greater than maximum value
+		 * that can be specified in seconds, we should
+		 * switch the timer to minutes mode by clearing
+		 * bit 7 of 0x72 (ensure that bit 5 is also cleared).
+		 *
+		 * For now, just disable the timer to honor the
+		 * watchdog(9) protocol.
+		 *
+		 * XXX The timeout actually can be up to 65535 units
+		 * as it is set via two registers 0x73, LSB, and 0x74,
+		 * MSB.  But it is not clear what the protocol for writing
+		 * those two registers is.
+		 */
+		if (timeout <= UINT8_MAX) {
+			val = timeout;
+			*error = 0;
+		} else {
+			/* error left unchanged */
+			val = 0;
+		}
+	} else {
+		val = 0;
+	}
+#ifdef DIAGNOSTIC
+	if (bootverbose)
+		device_printf(dev, "setting timeout to %d\n", val);
+#endif
+	superio_write(dev, 0x73, val);
+	if (superio_read(dev, 0x73) != val)
+		superio_write(dev, 0x73, val);
+}
+
+static void
+itwd_intr(void *cookie)
+{
+	device_t dev = cookie;
+	uint8_t val;
+
+	val = superio_read(dev, 0x71);
+	if (bootverbose)
+		device_printf(dev, "got interrupt, wdt status = %d\n", val & 1);
+	superio_write(dev, 0x71, val & ~((uint8_t)0x01));
+}
+
+static int
+itwd_probe(device_t dev)
+{
+
+	if (superio_vendor(dev) != SUPERIO_VENDOR_ITE)
+		return (ENXIO);
+	if (superio_get_type(dev) != SUPERIO_DEV_WDT)
+		return (ENXIO);
+	device_set_desc(dev, "Watchdog Timer on ITE SuperIO");
+	return (BUS_PROBE_DEFAULT);
+}
+
+static int
+itwd_attach(device_t dev)
+{
+	struct itwd_softc *sc = device_get_softc(dev);
+	int irq = 0;
+	int nmi = 0;
+	int error;
+
+	/* First, reset the timeout, just in case. */
+	superio_write(dev, 0x74, 0);
+	superio_write(dev, 0x73, 0);
+
+	TUNABLE_INT_FETCH("dev.itwd.irq", &irq);
+	TUNABLE_INT_FETCH("dev.itwd.nmi", &nmi);
+	if (irq < 0 || irq > 15) {
+		device_printf(dev, "Ignoring invalid IRQ value %d\n", irq);
+		irq = 0;
+	}
+	if (irq == 0 && nmi) {
+		device_printf(dev, "Ignoring NMI mode if IRQ is not set\n");
+		nmi = 0;
+	}
+
+	/*
+	 * NB: if the interrupt has been configured for the NMI delivery,
+	 * then it is not available for the regular interrupt allocation.
+	 * Thus, we configure the hardware to generate the interrupt,
+	 * but do not attempt to allocate and setup it as a regular
+	 * interrupt.
+	 */
+	if (irq != 0 && !nmi) {
+		sc->intr_rid = 0;
+		bus_set_resource(dev, SYS_RES_IRQ, sc->intr_rid, irq, 1);
+
+		sc->intr_res = bus_alloc_resource_any(dev, SYS_RES_IRQ,
+		    &sc->intr_rid, RF_ACTIVE);
+		if (sc->intr_res == NULL) {
+			device_printf(dev, "unable to map interrupt\n");
+			return (ENXIO);
+		}
+		error = bus_setup_intr(dev, sc->intr_res,
+		    INTR_TYPE_MISC | INTR_MPSAFE, NULL, itwd_intr, dev,
+		    &sc->intr_handle);
+		if (error != 0) {
+			bus_release_resource(dev, SYS_RES_IRQ,
+			    sc->intr_rid, sc->intr_res);
+			device_printf(dev, "Unable to setup irq: error %d\n",
+			    error);
+			return (ENXIO);
+		}
+	}
+	if (irq != 0) {
+		device_printf(dev, "Using IRQ%d to signal timeout\n", irq);
+	} else {
+		/* System reset via KBRST. */
+		irq = 0x40;
+		device_printf(dev, "Configured for system reset on timeout\n");
+	}
+
+	superio_write(dev, 0x71, 0);
+	superio_write(dev, 0x72, 0x80 | (uint8_t)irq);
+
+	sc->wd_ev = EVENTHANDLER_REGISTER(watchdog_list, wd_func, dev, 0);
+	return (0);
+}
+
+static int
+itwd_detach(device_t dev)
+{
+	struct itwd_softc *sc = device_get_softc(dev);
+	int dummy;
+
+	if (sc->wd_ev != NULL)
+		EVENTHANDLER_DEREGISTER(watchdog_list, sc->wd_ev);
+	wd_func(dev, 0, &dummy);
+	if (sc->intr_handle)
+		bus_teardown_intr(dev, sc->intr_res, sc->intr_handle);
+	if (sc->intr_res)
+		bus_release_resource(dev, SYS_RES_IRQ, sc->intr_rid,
+		    sc->intr_res);
+	return (0);
+}
+
+static device_method_t itwd_methods[] = {
+	/* Methods from the device interface */
+	DEVMETHOD(device_probe,		itwd_probe),
+	DEVMETHOD(device_attach,	itwd_attach),
+	DEVMETHOD(device_detach,	itwd_detach),
+
+	/* Terminate method list */
+	{ 0, 0 }
+};
+
+static driver_t itwd_driver = {
+	"itwd",
+	itwd_methods,
+	sizeof (struct itwd_softc)
+};
+
+static devclass_t itwd_devclass;
+
+DRIVER_MODULE(itwd, superio, itwd_driver, itwd_devclass, NULL, NULL);
+MODULE_DEPEND(itwd, superio, 1, 1, 1);
+MODULE_VERSION(itwd, 1);