* Driver for ACPI WMI (Windows Management Instrumentation)

* Driver for ACPI HP extra functionations, which required
  ACPI WMI driver.

Submitted by:	Michael <freebsdusb at bindone.de>
Approved by:	re
MFC after:	2 weeks

1 files changed, 1006 insertions, 0 deletions

diff --git a/sys/dev/acpi_support/acpi_wmi.c b/sys/dev/acpi_support/acpi_wmi.c
new file mode 100644
index 000000000000..3f4b511f1d3e
--- /dev/null
+++ b/sys/dev/acpi_support/acpi_wmi.c
@@ -0,0 +1,1006 @@
+/*-
+ * Copyright (c) 2009 Michael Gmelin <freebsd@grem.de>
+ * All rights reserved.
+ *
+ * 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("$FreeBSD$");
+
+/*
+ * Driver for acpi-wmi mapping, provides an interface for vendor specific
+ * implementations (e.g. HP and Acer laptops).
+ * Inspired by the ACPI-WMI mapping driver (c) 2008-2008 Carlos Corbacho which
+ * implements this functionality for Linux.
+ *
+ * WMI and ACPI: http://www.microsoft.com/whdc/system/pnppwr/wmi/wmi-acpi.mspx
+ * acpi-wmi for Linux: http://www.kernel.org
+ */
+
+#include "opt_acpi.h"
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/uio.h>
+#include <sys/proc.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/sbuf.h>
+#include <sys/module.h>
+#include <sys/bus.h>
+
+#include <contrib/dev/acpica/include/acpi.h>
+#include <contrib/dev/acpica/include/accommon.h>
+#include <dev/acpica/acpivar.h>
+#include "acpi_wmi_if.h"
+
+MALLOC_DEFINE(M_ACPIWMI, "acpiwmi", "ACPI-WMI mapping");
+
+#define _COMPONENT	ACPI_OEM
+ACPI_MODULE_NAME("ACPI_WMI");
+
+#define ACPI_WMI_REGFLAG_EXPENSIVE	0x1 /* GUID flag: Expensive operation */
+#define ACPI_WMI_REGFLAG_METHOD		0x2	/* GUID flag: Method call */
+#define ACPI_WMI_REGFLAG_STRING		0x4	/* GUID flag: String */
+#define ACPI_WMI_REGFLAG_EVENT		0x8	/* GUID flag: Event */
+
+/*
+ * acpi_wmi driver private structure
+ */
+struct acpi_wmi_softc {
+	device_t	wmi_dev;	/* wmi device id */
+	ACPI_HANDLE	wmi_handle;	/* handle of the PNP0C14 node */
+	device_t	ec_dev;		/* acpi_ec0 */
+	struct cdev	*wmistat_dev_t;	/* wmistat device handle */
+	struct sbuf	wmistat_sbuf;	/* sbuf for /dev/wmistat output */
+	pid_t		wmistat_open_pid; /* pid operating on /dev/wmistat */
+	int		wmistat_bufptr;	/* /dev/wmistat ptr to buffer position */
+};
+
+/*
+ * Struct that holds information about
+ * about a single GUID entry in _WDG
+ */
+struct guid_info {
+	char	guid[16];	/* 16 byte non human readable GUID */
+	char	oid[2];		/* object id or event notify id (first byte) */
+	UINT8	max_instance;	/* highest instance known for this GUID */
+	UINT8	flags;		/* ACPI_WMI_REGFLAG_%s */
+};
+
+/* WExx event generation state (on/off) */
+enum event_generation_state {
+	EVENT_GENERATION_ON = 1,
+	EVENT_GENERATION_OFF = 0
+};
+
+
+/*
+ * Information about one entry in _WDG.
+ * List of those is used to lookup information by GUID.
+ */
+struct wmi_info {
+	TAILQ_ENTRY(wmi_info)	wmi_list;
+	struct guid_info	ginfo;		/* information on guid */
+	ACPI_NOTIFY_HANDLER	event_handler;/* client provided event handler */
+	void			*event_handler_user_data; /* ev handler cookie  */
+};
+
+TAILQ_HEAD(wmi_info_list_head, wmi_info)
+    wmi_info_list = TAILQ_HEAD_INITIALIZER(wmi_info_list);
+
+ACPI_SERIAL_DECL(acpi_wmi, "ACPI-WMI Mapping");
+
+/* public interface - declaration */
+/* standard device interface*/
+static int		acpi_wmi_probe(device_t dev);
+static int		acpi_wmi_attach(device_t dev);
+static int		acpi_wmi_detach(device_t dev);
+/* see acpi_wmi_if.m */
+static int		acpi_wmi_provides_guid_string_method(device_t dev,
+			    const char *guid_string);
+static ACPI_STATUS	acpi_wmi_evaluate_call_method(device_t dev,
+			    const char *guid_string, UINT8 instance,
+			    UINT32 method_id, const ACPI_BUFFER *in,
+			    ACPI_BUFFER *out);
+static ACPI_STATUS	acpi_wmi_install_event_handler_method(device_t dev,
+			    const char *guid_string, ACPI_NOTIFY_HANDLER handler,
+			    void *data);
+static ACPI_STATUS	acpi_wmi_remove_event_handler_method(device_t dev,
+			    const char *guid_string);
+static ACPI_STATUS	acpi_wmi_get_event_data_method(device_t dev,
+			    UINT32 event_id, ACPI_BUFFER *out);
+static ACPI_STATUS	acpi_wmi_get_block_method(device_t dev,
+			    const char *guid_string,
+			    UINT8 instance, ACPI_BUFFER *out);
+static ACPI_STATUS	acpi_wmi_set_block_method(device_t dev,
+			    const char *guid_string,
+			    UINT8 instance, const ACPI_BUFFER *in);
+/* private interface - declaration */
+/* callbacks */
+static void		acpi_wmi_notify_handler(ACPI_HANDLE h, UINT32 notify,
+			    void *context);
+static ACPI_STATUS	acpi_wmi_ec_handler(UINT32 function,
+			    ACPI_PHYSICAL_ADDRESS address, UINT32 width,
+			    ACPI_INTEGER *value, void *context,
+			    void *region_context);
+/* helpers */
+static ACPI_STATUS	acpi_wmi_read_wdg_blocks(ACPI_HANDLE h);
+static ACPI_STATUS	acpi_wmi_toggle_we_event_generation(device_t dev,
+			    struct wmi_info *winfo,
+			    enum event_generation_state state);
+static int		acpi_wmi_guid_string_to_guid(const UINT8 *guid_string,
+			    UINT8 *guid);
+static struct wmi_info* acpi_wmi_lookup_wmi_info_by_guid_string(
+			    const char *guid_string);
+
+static d_open_t acpi_wmi_wmistat_open;
+static d_close_t acpi_wmi_wmistat_close;
+static d_read_t acpi_wmi_wmistat_read;
+
+/* handler /dev/wmistat device */
+static struct cdevsw wmistat_cdevsw = {
+	.d_version = D_VERSION,
+	.d_open = acpi_wmi_wmistat_open,
+	.d_close = acpi_wmi_wmistat_close,
+	.d_read = acpi_wmi_wmistat_read,
+	.d_name = "wmistat",
+};
+
+
+static device_method_t acpi_wmi_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,	acpi_wmi_probe),
+	DEVMETHOD(device_attach, acpi_wmi_attach),
+	DEVMETHOD(device_detach, acpi_wmi_detach),
+
+	/* acpi_wmi interface */
+	DEVMETHOD(acpi_wmi_provides_guid_string,
+		    acpi_wmi_provides_guid_string_method),
+	DEVMETHOD(acpi_wmi_evaluate_call, acpi_wmi_evaluate_call_method),
+	DEVMETHOD(acpi_wmi_install_event_handler,
+		    acpi_wmi_install_event_handler_method),
+	DEVMETHOD(acpi_wmi_remove_event_handler,
+		    acpi_wmi_remove_event_handler_method),
+	DEVMETHOD(acpi_wmi_get_event_data, acpi_wmi_get_event_data_method),
+	DEVMETHOD(acpi_wmi_get_block, acpi_wmi_get_block_method),
+	DEVMETHOD(acpi_wmi_set_block, acpi_wmi_set_block_method),
+
+	{0, 0}
+};
+
+static driver_t acpi_wmi_driver = {
+	"acpi_wmi",
+	acpi_wmi_methods,
+	sizeof(struct acpi_wmi_softc),
+};
+
+static devclass_t acpi_wmi_devclass;
+DRIVER_MODULE(acpi_wmi, acpi, acpi_wmi_driver, acpi_wmi_devclass, 0, 0);
+MODULE_VERSION(acpi_wmi, 1);
+MODULE_DEPEND(acpi_wmi, acpi, 1, 1, 1);
+static char *wmi_ids[] = {"PNP0C14", "PNP0c14", NULL};
+
+/*
+ * Probe for the PNP0C14 ACPI node
+ */
+static int
+acpi_wmi_probe(device_t dev)
+{
+	if (acpi_disabled("wmi") ||
+	    ACPI_ID_PROBE(device_get_parent(dev), dev, wmi_ids) == NULL)
+		return (ENXIO);
+	device_set_desc(dev, "ACPI-WMI mapping");
+
+	return (0);
+}
+
+/*
+ * Attach the device by:
+ * - Looking for the first ACPI EC device
+ * - Install the notify handler
+ * - Install the EC address space handler
+ * - Look for the _WDG node and read GUID information blocks
+ */
+static int
+acpi_wmi_attach(device_t dev)
+{
+	struct acpi_wmi_softc *sc;
+	int ret;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+	sc = device_get_softc(dev);
+	ret = ENXIO;
+
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	sc->wmi_dev = dev;
+	sc->wmi_handle = acpi_get_handle(dev);
+	TAILQ_INIT(&wmi_info_list);
+	/* XXX Only works with one EC, but nearly all systems only have one. */
+	if ((sc->ec_dev = devclass_get_device(devclass_find("acpi_ec"), 0))
+	    == NULL)
+		device_printf(dev, "cannot find EC device\n");
+	else if (ACPI_FAILURE((status = AcpiInstallNotifyHandler(sc->wmi_handle,
+		    ACPI_DEVICE_NOTIFY, acpi_wmi_notify_handler, sc))))
+		device_printf(sc->wmi_dev, "couldn't install notify handler - %s\n",
+		    AcpiFormatException(status));
+	else if (ACPI_FAILURE((status = AcpiInstallAddressSpaceHandler(
+		    sc->wmi_handle, ACPI_ADR_SPACE_EC, acpi_wmi_ec_handler,
+		    NULL, sc)))) {
+		device_printf(sc->wmi_dev, "couldn't install EC handler - %s\n",
+		    AcpiFormatException(status));
+		AcpiRemoveNotifyHandler(sc->wmi_handle, ACPI_DEVICE_NOTIFY,
+		    acpi_wmi_notify_handler);
+	} else if (ACPI_FAILURE((status = acpi_wmi_read_wdg_blocks(
+		    sc->wmi_handle)))) {
+		device_printf(sc->wmi_dev, "couldn't parse _WDG - %s\n",
+		    AcpiFormatException(status));
+		AcpiRemoveNotifyHandler(sc->wmi_handle, ACPI_DEVICE_NOTIFY,
+		    acpi_wmi_notify_handler);
+		AcpiRemoveAddressSpaceHandler(sc->wmi_handle, ACPI_ADR_SPACE_EC,
+		    acpi_wmi_ec_handler);
+	} else {
+		sc->wmistat_dev_t = make_dev(&wmistat_cdevsw, 0, UID_ROOT,
+		    GID_WHEEL, 0644, "wmistat");
+		sc->wmistat_dev_t->si_drv1 = sc;
+		sc->wmistat_open_pid = 0;
+		sc->wmistat_bufptr = -1;
+		ret = 0;
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}
+
+/*
+ * Detach the driver by:
+ * - Removing notification handler
+ * - Removing address space handler
+ * - Turning off event generation for all WExx event activated by
+ *   child drivers
+ */
+static int
+acpi_wmi_detach(device_t dev)
+{
+	struct wmi_info *winfo, *tmp;
+	struct acpi_wmi_softc *sc;
+	int ret;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+	sc = device_get_softc(dev);
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+
+	if (sc->wmistat_open_pid != 0) {
+		ret = EBUSY;
+	} else {
+		AcpiRemoveNotifyHandler(sc->wmi_handle, ACPI_DEVICE_NOTIFY,
+		    acpi_wmi_notify_handler);
+		AcpiRemoveAddressSpaceHandler(sc->wmi_handle,
+		    ACPI_ADR_SPACE_EC, acpi_wmi_ec_handler);
+		TAILQ_FOREACH_SAFE(winfo, &wmi_info_list, wmi_list, tmp) {
+			if (winfo->event_handler)
+				acpi_wmi_toggle_we_event_generation(dev,
+				    winfo, EVENT_GENERATION_OFF);
+			TAILQ_REMOVE(&wmi_info_list, winfo, wmi_list);
+			free(winfo, M_ACPIWMI);
+		}
+		if (sc->wmistat_bufptr != -1) {
+			sbuf_delete(&sc->wmistat_sbuf);
+			sc->wmistat_bufptr = -1;
+		}
+		sc->wmistat_open_pid = 0;
+		destroy_dev(sc->wmistat_dev_t);
+		ret = 0;
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}
+
+
+/*
+ * Check if the given GUID string (human readable format
+ * AABBCCDD-EEFF-GGHH-IIJJ-KKLLMMNNOOPP)
+ * exists within _WDG
+ */
+static int
+acpi_wmi_provides_guid_string_method(device_t dev, const char *guid_string)
+{
+	int ret;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	ret = (acpi_wmi_lookup_wmi_info_by_guid_string(guid_string) == NULL)?0:1;
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}
+
+/*
+ * Call a method "method_id" on the given GUID block
+ * write result into user provided output buffer
+ */
+static ACPI_STATUS
+acpi_wmi_evaluate_call_method(device_t dev, const char *guid_string,
+    UINT8 instance, UINT32 method_id, const ACPI_BUFFER *in, ACPI_BUFFER *out)
+{
+	ACPI_OBJECT params[3];
+	ACPI_OBJECT_LIST input;
+	char method[5] = "WMxx";
+	struct wmi_info *winfo;
+	struct acpi_wmi_softc *sc;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if ((winfo = acpi_wmi_lookup_wmi_info_by_guid_string(guid_string))
+		    == NULL)
+		status = AE_NOT_FOUND;
+	else if (!(winfo->ginfo.flags & ACPI_WMI_REGFLAG_METHOD))
+		status = AE_BAD_DATA;
+	else if (instance > winfo->ginfo.max_instance)
+		status = AE_BAD_PARAMETER;
+	else {
+		params[0].Type = ACPI_TYPE_INTEGER;
+		params[0].Integer.Value = instance;
+		params[1].Type = ACPI_TYPE_INTEGER;
+		params[1].Integer.Value = method_id;
+		input.Pointer = params;
+		input.Count = 2;
+		if (in) {
+			params[2].Type =
+			    (winfo->ginfo.flags & ACPI_WMI_REGFLAG_STRING)
+			    ?ACPI_TYPE_STRING:ACPI_TYPE_BUFFER;
+			params[2].Buffer.Length = in->Length;
+			params[2].Buffer.Pointer = in->Pointer;
+			input.Count = 3;
+		}
+		method[2] = winfo->ginfo.oid[0];
+		method[3] = winfo->ginfo.oid[1];
+		status = AcpiEvaluateObject(sc->wmi_handle, method,
+			    &input, out);
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Install a user provided event_handler on the given GUID
+ * provided *data will be passed on callback
+ * If there is already an existing event handler registered it will be silently
+ * discarded
+ */
+static ACPI_STATUS
+acpi_wmi_install_event_handler_method(device_t dev, const char *guid_string,
+    ACPI_NOTIFY_HANDLER event_handler, void *data)
+{
+	struct wmi_info *winfo;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	status = AE_OK;
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (guid_string == NULL || event_handler == NULL)
+		status = AE_BAD_PARAMETER;
+	else if ((winfo = acpi_wmi_lookup_wmi_info_by_guid_string(guid_string))
+		    == NULL)
+		status = AE_NOT_EXIST;
+	else if (winfo->event_handler != NULL ||
+		(status = acpi_wmi_toggle_we_event_generation(dev, winfo,
+		    EVENT_GENERATION_ON)) == AE_OK) {
+		winfo->event_handler = event_handler;
+		winfo->event_handler_user_data = data;
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Remove a previously installed event handler from the given GUID
+ * If there was none installed, this call is silently discarded and
+ * reported as AE_OK
+ */
+static ACPI_STATUS
+acpi_wmi_remove_event_handler_method(device_t dev, const char *guid_string)
+{
+	struct wmi_info *winfo;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	status = AE_OK;
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (guid_string &&
+	    (winfo = acpi_wmi_lookup_wmi_info_by_guid_string(guid_string))
+	    != NULL && winfo->event_handler) {
+		status = acpi_wmi_toggle_we_event_generation(dev, winfo,
+			    EVENT_GENERATION_OFF);
+		winfo->event_handler = NULL;
+		winfo->event_handler_user_data = NULL;
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Get details on an event received through a callback registered
+ * through ACPI_WMI_REMOVE_EVENT_HANDLER into a user provided output buffer.
+ * (event_id equals "notify" passed in the callback)
+ */
+static ACPI_STATUS
+acpi_wmi_get_event_data_method(device_t dev, UINT32 event_id, ACPI_BUFFER *out)
+{
+	ACPI_OBJECT_LIST input;
+	ACPI_OBJECT params[1];
+	struct acpi_wmi_softc *sc;
+	struct wmi_info *winfo;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	status = AE_NOT_FOUND;	
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	params[0].Type = ACPI_TYPE_INTEGER;
+	params[0].Integer.Value = event_id;
+	input.Pointer = params;
+	input.Count = 1;
+	TAILQ_FOREACH(winfo, &wmi_info_list, wmi_list) {
+		if ((winfo->ginfo.flags & ACPI_WMI_REGFLAG_EVENT) &&
+		    ((UINT8) winfo->ginfo.oid[0] == event_id)) {
+			status = AcpiEvaluateObject(sc->wmi_handle, "_WED",
+				    &input, out);
+			break;
+		}
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Read a block of data from the given GUID (using WQxx (query))
+ * Will be returned in a user provided buffer (out).
+ * If the method is marked as expensive (ACPI_WMI_REGFLAG_EXPENSIVE)
+ * we will first call the WCxx control method to lock the node to
+ * lock the node for data collection and release it afterwards.
+ * (Failed WCxx calls are ignored to "support" broken implementations)
+ */
+static ACPI_STATUS
+acpi_wmi_get_block_method(device_t dev, const char *guid_string, UINT8 instance,
+	ACPI_BUFFER *out)
+{
+	char wc_method[5] = "WCxx";
+	char wq_method[5] = "WQxx";
+	ACPI_OBJECT_LIST wc_input;
+	ACPI_OBJECT_LIST wq_input;
+	ACPI_OBJECT wc_params[1];
+	ACPI_OBJECT wq_params[1];
+	ACPI_HANDLE wc_handle;
+	struct acpi_wmi_softc *sc;
+	struct wmi_info *winfo;
+	ACPI_STATUS status;
+	ACPI_STATUS wc_status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	wc_status = AE_ERROR;
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (guid_string == NULL || out == NULL)
+		status = AE_BAD_PARAMETER;
+	else if ((winfo = acpi_wmi_lookup_wmi_info_by_guid_string(guid_string))
+		    == NULL)
+		status = AE_ERROR;
+	else if (instance > winfo->ginfo.max_instance)
+		status = AE_BAD_PARAMETER;
+	else if ((winfo->ginfo.flags & ACPI_WMI_REGFLAG_EVENT) ||
+	    (winfo->ginfo.flags & ACPI_WMI_REGFLAG_METHOD))
+		status = AE_ERROR;
+	else {
+		wq_params[0].Type = ACPI_TYPE_INTEGER;
+		wq_params[0].Integer.Value = instance;
+		wq_input.Pointer = wq_params;
+		wq_input.Count = 1;
+		if (winfo->ginfo.flags & ACPI_WMI_REGFLAG_EXPENSIVE) {
+			wc_params[0].Type = ACPI_TYPE_INTEGER;
+			wc_params[0].Integer.Value = 1;
+			wc_input.Pointer = wc_params;
+			wc_input.Count = 1;
+			wc_method[2] = winfo->ginfo.oid[0];
+			wc_method[3] = winfo->ginfo.oid[1];
+			wc_status = AcpiGetHandle(sc->wmi_handle, wc_method,
+				    &wc_handle);
+			if (ACPI_SUCCESS(wc_status))
+				wc_status = AcpiEvaluateObject(wc_handle,
+						wc_method, &wc_input, NULL);
+		}
+		wq_method[2] = winfo->ginfo.oid[0];
+		wq_method[3] = winfo->ginfo.oid[1];
+		status = AcpiEvaluateObject(sc->wmi_handle, wq_method,
+			    &wq_input, out);
+		if ((winfo->ginfo.flags & ACPI_WMI_REGFLAG_EXPENSIVE)
+		    && ACPI_SUCCESS(wc_status)) {
+			wc_params[0].Integer.Value = 0;
+			status = AcpiEvaluateObject(wc_handle, wc_method,
+				    &wc_input, NULL);  /* XXX this might be
+				    			 the wrong status to
+				    			 return? */
+		}
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Write a block of data to the given GUID (using WSxx)
+ */
+static ACPI_STATUS
+acpi_wmi_set_block_method(device_t dev, const char *guid_string, UINT8 instance,
+	const ACPI_BUFFER *in)
+{
+	char method[5] = "WSxx";
+	ACPI_OBJECT_LIST input;
+	ACPI_OBJECT params[2];
+	struct wmi_info *winfo;
+	struct acpi_wmi_softc *sc;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (guid_string == NULL || in == NULL)
+		status = AE_BAD_DATA;
+	else if ((winfo = acpi_wmi_lookup_wmi_info_by_guid_string(guid_string))
+		    == NULL)
+		status = AE_ERROR;
+	else if (instance > winfo->ginfo.max_instance)
+		status = AE_BAD_PARAMETER;
+	else if ((winfo->ginfo.flags & ACPI_WMI_REGFLAG_EVENT) ||
+		    (winfo->ginfo.flags & ACPI_WMI_REGFLAG_METHOD))
+		status = AE_ERROR;
+	else {
+		params[0].Type = ACPI_TYPE_INTEGER;
+		params[0].Integer.Value = instance;
+		input.Pointer = params;
+		input.Count = 2;
+		params[1].Type = (winfo->ginfo.flags & ACPI_WMI_REGFLAG_STRING)
+		    ?ACPI_TYPE_STRING:ACPI_TYPE_BUFFER;
+		params[1].Buffer.Length = in->Length;
+		params[1].Buffer.Pointer = in->Pointer;
+		method[2] = winfo->ginfo.oid[0];
+		method[3] = winfo->ginfo.oid[1];
+		status = AcpiEvaluateObject(sc->wmi_handle, method,
+			    &input, NULL);
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (status);
+}
+
+/*
+ * Handle events received and dispatch them to
+ * stakeholders that registered through ACPI_WMI_INSTALL_EVENT_HANDLER
+ */
+static void
+acpi_wmi_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
+{
+	ACPI_NOTIFY_HANDLER handler;
+	void *handler_data;
+	struct wmi_info *winfo;
+
+	ACPI_FUNCTION_TRACE_U32((char *)(uintptr_t)__func__, notify);
+
+	handler = NULL;
+	handler_data = NULL;
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	TAILQ_FOREACH(winfo, &wmi_info_list, wmi_list) {
+		if ((winfo->ginfo.flags & ACPI_WMI_REGFLAG_EVENT) &&
+				((UINT8) winfo->ginfo.oid[0] == notify)) {
+			if (winfo->event_handler) {
+				handler = winfo->event_handler;
+				handler_data = winfo->event_handler_user_data;
+				break;
+			}
+		}
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+	if (handler) {
+		handler(h, notify, handler_data);
+	}
+}
+
+/*
+ * Handle EC address space notifications reveived on the WDG node
+ * (this mimics EcAddressSpaceHandler in acpi_ec.c)
+ */
+static ACPI_STATUS
+acpi_wmi_ec_handler(UINT32 function, ACPI_PHYSICAL_ADDRESS address,
+    UINT32 width, ACPI_INTEGER *value, void *context,
+    void *region_context)
+{
+	struct acpi_wmi_softc *sc;
+	int i;
+	ACPI_INTEGER ec_data;
+	UINT8 ec_addr;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE_U32((char *)(uintptr_t)__func__, (UINT32)Address);
+
+	sc = (struct acpi_wmi_softc *)context;
+	if (width % 8 != 0 || value == NULL || context == NULL)
+		return (AE_BAD_PARAMETER);
+	if (address + (width / 8) - 1 > 0xFF)
+		return (AE_BAD_ADDRESS);
+	if (function == ACPI_READ)
+		*value = 0;
+	ec_addr = address;
+	status = AE_ERROR;
+
+	for (i = 0; i < width; i += 8, ++ec_addr) {
+		switch (function) {
+		case ACPI_READ:
+			status = ACPI_EC_READ(sc->ec_dev, ec_addr, &ec_data, 1);
+			if (ACPI_SUCCESS(status))
+				*value |= ((ACPI_INTEGER)ec_data) << i;
+		break;
+		case ACPI_WRITE:
+			ec_data = (UINT8)((*value) >> i);
+			status = ACPI_EC_WRITE(sc->ec_dev, ec_addr, ec_data, 1);
+			break;
+		default:
+			device_printf(sc->wmi_dev,
+			    "invalid acpi_wmi_ec_handler function %d\n",
+			    function);
+			status = AE_BAD_PARAMETER;
+			break;
+		}
+		if (ACPI_FAILURE(status))
+			break;
+	}
+
+	return (status);
+}
+
+/*
+ * Read GUID blocks from the _WDG node
+ * into wmi_info_list.
+ */
+static ACPI_STATUS
+acpi_wmi_read_wdg_blocks(ACPI_HANDLE h)
+{
+	ACPI_BUFFER out = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct guid_info *ginfo;
+	ACPI_OBJECT *obj;
+	struct wmi_info *winfo;
+	UINT32 i;
+	UINT32 wdg_block_count;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	ACPI_SERIAL_ASSERT(acpi_wmi);
+	if (ACPI_FAILURE(status = AcpiEvaluateObject(h, "_WDG", NULL, &out)))
+		return (status);
+	obj = (ACPI_OBJECT*) out.Pointer;
+	wdg_block_count = obj->Buffer.Length / sizeof(struct guid_info);
+	if ((ginfo = malloc(obj->Buffer.Length, M_ACPIWMI, M_NOWAIT))
+		    == NULL) {
+		AcpiOsFree(out.Pointer);
+		return (AE_NO_MEMORY);
+	}
+	memcpy(ginfo, obj->Buffer.Pointer, obj->Buffer.Length);
+	for (i = 0; i < wdg_block_count; ++i) {
+		if ((winfo = malloc(sizeof(struct wmi_info), M_ACPIWMI,
+			    M_NOWAIT | M_ZERO)) == NULL) {
+			AcpiOsFree(out.Pointer);
+			free(ginfo, M_ACPIWMI);
+			return (AE_NO_MEMORY);
+		}
+		winfo->ginfo = ginfo[i];
+		TAILQ_INSERT_TAIL(&wmi_info_list, winfo, wmi_list);
+	}
+	AcpiOsFree(out.Pointer);
+	free(ginfo, M_ACPIWMI);
+
+	return (status);
+}
+
+/*
+ * Toggle event generation in for the given GUID (passed by winfo)
+ * Turn on to get notified (through acpi_wmi_notify_handler) if events happen
+ * on the given GUID.
+ */
+static ACPI_STATUS
+acpi_wmi_toggle_we_event_generation(device_t dev, struct wmi_info *winfo,
+    enum event_generation_state state)
+{
+	char method[5] = "WExx";
+	ACPI_OBJECT_LIST input;
+	ACPI_OBJECT params[1];
+	struct acpi_wmi_softc *sc;
+	ACPI_STATUS status;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	ACPI_SERIAL_ASSERT(acpi_wmi);
+	params[0].Type = ACPI_TYPE_INTEGER;
+	params[0].Integer.Value = state==EVENT_GENERATION_ON?1:0;
+	input.Pointer = params;
+	input.Count = 1;
+	
+	UINT8 hi = ((UINT8) winfo->ginfo.oid[0]) >> 4;
+	UINT8 lo = ((UINT8) winfo->ginfo.oid[0]) & 0xf;
+	method[2] = (hi > 9 ? hi + 55: hi + 48);
+	method[3] = (lo > 9 ? lo + 55: lo + 48);
+	status = AcpiEvaluateObject(sc->wmi_handle, method, &input, NULL);
+	if (status == AE_NOT_FOUND) status = AE_OK;
+
+	return (status);
+}
+
+/*
+ * Convert given two digit hex string (hexin) to an UINT8 referenced
+ * by byteout.
+ * Return != 0 if the was a problem (invalid input)
+ */
+static __inline int acpi_wmi_hex_to_int(const UINT8 *hexin, UINT8 *byteout)
+{
+	unsigned int hi;
+	unsigned int lo;
+
+	hi = hexin[0];
+	lo = hexin[1];
+	if ('0' <= hi && hi <= '9')
+		hi -= '0';
+	else if ('A' <= hi && hi <= 'F')
+		hi -= ('A' - 10);
+	else if ('a' <= hi && hi <= 'f')
+		hi -= ('a' - 10);
+	else
+		return (1);
+	if ('0' <= lo && lo <= '9')
+		lo -= '0';
+	else if ('A' <= lo && lo <= 'F')
+		lo -= ('A' - 10);
+	else if ('a' <= lo && lo <= 'f')
+		lo -= ('a' - 10);
+	else
+		return (1);
+	*byteout = (hi << 4) + lo;
+
+	return (0);
+}
+
+/*
+ * Convert a human readable 36 character GUID into a 16byte
+ * machine readable one.
+ * The basic algorithm looks as follows:
+ * Input:  AABBCCDD-EEFF-GGHH-IIJJ-KKLLMMNNOOPP
+ * Output: DCBAFEHGIJKLMNOP
+ * (AA BB CC etc. represent two digit hex numbers == bytes)
+ * Return != 0 if passed guid string is invalid
+ */
+static int
+acpi_wmi_guid_string_to_guid(const UINT8 *guid_string, UINT8 *guid)
+{
+	static const int mapping[20] = {3, 2, 1, 0, -1, 5, 4, -1, 7, 6, -1,
+	    8, 9, -1, 10, 11, 12, 13, 14, 15};
+	int i;
+
+	for (i = 0; i < 20; ++i, ++guid_string) {
+		if (mapping[i] >= 0) {
+			if (acpi_wmi_hex_to_int(guid_string,
+			    &guid[mapping[i]]))
+				return (-1);
+			++guid_string;
+		} else if (*guid_string != '-')
+			return (-1);
+	}
+
+	return (0);
+}
+
+/*
+ * Lookup a wmi_info structure in wmi_list based on a
+ * human readable GUID
+ * Return NULL if the GUID is unknown in the _WDG
+ */
+static struct wmi_info*
+acpi_wmi_lookup_wmi_info_by_guid_string(const char *guid_string)
+{
+	char guid[16];
+	struct wmi_info *winfo;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	ACPI_SERIAL_ASSERT(acpi_wmi);
+
+	if (!acpi_wmi_guid_string_to_guid(guid_string, guid)) {
+		TAILQ_FOREACH(winfo, &wmi_info_list, wmi_list) {
+			if (!memcmp(winfo->ginfo.guid, guid, 16)) {
+				return (winfo);
+			}
+		}
+	}
+
+	return (NULL);
+}
+
+/*
+ * open wmistat device
+ */
+static int
+acpi_wmi_wmistat_open(struct cdev* dev, int flags, int mode, struct thread *td)
+{
+	struct acpi_wmi_softc *sc;
+	int ret;
+
+	if (dev == NULL || dev->si_drv1 == NULL)
+		return (EBADF);
+	sc = dev->si_drv1;
+
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (sc->wmistat_open_pid != 0) {
+		ret = EBUSY;
+	}
+	else {
+		if (sbuf_new(&sc->wmistat_sbuf, NULL, 4096, SBUF_AUTOEXTEND)
+			    == NULL) {
+			ret = ENXIO;
+		} else {
+			sc->wmistat_open_pid = td->td_proc->p_pid;
+			sc->wmistat_bufptr = 0;
+			ret = 0;
+		}
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}
+
+/*
+ * close wmistat device
+ */
+static int
+acpi_wmi_wmistat_close(struct cdev* dev, int flags, int mode,
+    struct thread *td)
+{
+	struct acpi_wmi_softc *sc;
+	int ret;
+
+	if (dev == NULL || dev->si_drv1 == NULL)
+		return (EBADF);
+	sc = dev->si_drv1;
+
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (sc->wmistat_open_pid == 0) {
+		ret = EBADF;
+	}
+	else {
+		if (sc->wmistat_bufptr != -1) {
+			sbuf_delete(&sc->wmistat_sbuf);
+			sc->wmistat_bufptr = -1;
+		}
+		sc->wmistat_open_pid = 0;
+		ret = 0;
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}
+
+/*
+ * Read from wmistat guid information
+ */
+static int
+acpi_wmi_wmistat_read(struct cdev *dev, struct uio *buf, int flag)
+{
+	struct acpi_wmi_softc *sc;
+	struct wmi_info *winfo;
+	int l;
+	int ret;
+	UINT8* guid;
+
+	if (dev == NULL || dev->si_drv1 == NULL)
+		return (EBADF);
+	sc = dev->si_drv1;
+	
+	ACPI_SERIAL_BEGIN(acpi_wmi);
+	if (sc->wmistat_open_pid != buf->uio_td->td_proc->p_pid ||
+			sc->wmistat_bufptr == -1) {
+		ret = EBADF;
+	}
+	else {
+		if (!sbuf_done(&sc->wmistat_sbuf)) {
+			sbuf_printf(&sc->wmistat_sbuf, "GUID                 "
+				    "                 INST EXPE METH STR "
+				    "EVENT OID\n");
+			TAILQ_FOREACH(winfo, &wmi_info_list, wmi_list) {
+				guid = (UINT8*)winfo->ginfo.guid;
+				sbuf_printf(&sc->wmistat_sbuf,
+					    "{%02X%02X%02X%02X-%02X%02X-"
+					    "%02X%02X-%02X%02X-%02X%02X"
+					    "%02X%02X%02X%02X} %3d %-5s",
+					guid[3], guid[2], guid[1], guid[0],
+					guid[5], guid[4],
+					guid[7], guid[6],
+					guid[8], guid[9],
+					guid[10], guid[11], guid[12],
+					guid[13], guid[14], guid[15],
+					winfo->ginfo.max_instance,
+					(winfo->ginfo.flags&
+						ACPI_WMI_REGFLAG_EXPENSIVE)?
+						"YES":"NO"
+					);
+				if (winfo->ginfo.flags&ACPI_WMI_REGFLAG_METHOD)
+					sbuf_printf(&sc->wmistat_sbuf,
+						    "WM%c%c ",
+						    winfo->ginfo.oid[0],
+						    winfo->ginfo.oid[1]);
+				else
+					sbuf_printf(&sc->wmistat_sbuf, "NO   ");
+				sbuf_printf(&sc->wmistat_sbuf, "%-4s",
+					    (winfo->ginfo.flags&
+					    ACPI_WMI_REGFLAG_STRING)?"YES":"NO"
+					);
+				if (winfo->ginfo.flags&ACPI_WMI_REGFLAG_EVENT)
+					sbuf_printf(&sc->wmistat_sbuf,
+						    "0x%02X%s -\n",
+						    (UINT8)winfo->ginfo.oid[0],
+						    winfo->event_handler==NULL?
+						    " ":"+");
+				else
+					sbuf_printf(&sc->wmistat_sbuf,
+						    "NO    %c%c\n",
+						    winfo->ginfo.oid[0],
+						    winfo->ginfo.oid[1]);
+			}
+			sbuf_finish(&sc->wmistat_sbuf);
+		}
+		if (sbuf_len(&sc->wmistat_sbuf) <= 0) {
+			sbuf_delete(&sc->wmistat_sbuf);
+			sc->wmistat_bufptr = -1;
+			sc->wmistat_open_pid = 0;
+			ret = ENOMEM;
+		} else {
+			l = min(buf->uio_resid, sbuf_len(&sc->wmistat_sbuf) -
+				    sc->wmistat_bufptr);
+			ret = (l > 0)?uiomove(sbuf_data(&sc->wmistat_sbuf) +
+				    sc->wmistat_bufptr, l, buf) : 0;
+			sc->wmistat_bufptr += l;
+		}
+	}
+	ACPI_SERIAL_END(acpi_wmi);
+
+	return (ret);
+}