Commit 92b8c540 authored by Mario Limonciello's avatar Mario Limonciello Committed by Darren Hart (VMware)
Browse files

platform/x86: dell-wmi-descriptor: split WMI descriptor into it's own driver 



All communication on individual GUIDs should occur in separate drivers.
Allowing a driver to communicate with the bus to another GUID is just
a hack that discourages drivers to adopt the bus model.

The information found from the WMI descriptor driver is now exported
for use by other drivers.

Signed-off-by: default avatarMario Limonciello <mario.limonciello@dell.com>
Reviewed-by: default avatarEdward O'Callaghan <quasisec@google.com>
Signed-off-by: default avatarDarren Hart (VMware) <dvhart@infradead.org>
parent fa9f924c

MAINTAINERS

+5 −0
Original line number Diff line number Diff line
@@ -4013,6 +4013,11 @@ M: Pali Rohár <pali.rohar@gmail.com> 
S:	Maintained

F:	drivers/platform/x86/dell-wmi.c



DELL WMI DESCRIPTOR DRIVER

M:	Mario Limonciello <mario.limonciello@dell.com>

S:	Maintained

F:	drivers/platform/x86/dell-wmi-descriptor.c



DELTA ST MEDIA DRIVER

M:	Hugues Fruchet <hugues.fruchet@st.com>

L:	linux-media@vger.kernel.org

drivers/platform/x86/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ config DELL_WMI 
	depends on DMI

	depends on INPUT

	depends on ACPI_VIDEO || ACPI_VIDEO = n

	select DELL_WMI_DESCRIPTOR

	select DELL_SMBIOS

	select INPUT_SPARSEKMAP

	---help---
@@ -129,6 +130,10 @@ config DELL_WMI 
	  To compile this driver as a module, choose M here: the module will

	  be called dell-wmi.



config DELL_WMI_DESCRIPTOR

	tristate

	depends on ACPI_WMI



config DELL_WMI_AIO

	tristate "WMI Hotkeys for Dell All-In-One series"

	depends on ACPI_WMI

drivers/platform/x86/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ obj-$(CONFIG_COMPAL_LAPTOP) += compal-laptop.o 
obj-$(CONFIG_DELL_SMBIOS)	+= dell-smbios.o

obj-$(CONFIG_DELL_LAPTOP)	+= dell-laptop.o

obj-$(CONFIG_DELL_WMI)		+= dell-wmi.o

obj-$(CONFIG_DELL_WMI_DESCRIPTOR)	+= dell-wmi-descriptor.o

obj-$(CONFIG_DELL_WMI_AIO)	+= dell-wmi-aio.o

obj-$(CONFIG_DELL_WMI_LED)	+= dell-wmi-led.o

obj-$(CONFIG_DELL_SMO8800)	+= dell-smo8800.o

drivers/platform/x86/dell-wmi-descriptor.c

0 → 100644
+170 −0
Original line number Diff line number Diff line 
/*

 * Dell WMI descriptor driver

 *

 * Copyright (C) 2017 Dell Inc. All Rights Reserved.

 *

 *  This program is free software; you can redistribute it and/or modify it

 *  under the terms of the GNU General Public License version 2 as published

 *  by the Free Software Foundation.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 */



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/acpi.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/wmi.h>

#include "dell-wmi-descriptor.h"



struct descriptor_priv {

	struct list_head list;

	u32 interface_version;

	u32 size;

};

static LIST_HEAD(wmi_list);

static DEFINE_MUTEX(list_mutex);



bool dell_wmi_get_interface_version(u32 *version)

{

	struct descriptor_priv *priv;

	bool ret = false;



	mutex_lock(&list_mutex);

	priv = list_first_entry_or_null(&wmi_list,

					struct descriptor_priv,

					list);

	if (priv) {

		*version = priv->interface_version;

		ret = true;

	}

	mutex_unlock(&list_mutex);

	return ret;

}

EXPORT_SYMBOL_GPL(dell_wmi_get_interface_version);



bool dell_wmi_get_size(u32 *size)

{

	struct descriptor_priv *priv;

	bool ret = false;



	mutex_lock(&list_mutex);

	priv = list_first_entry_or_null(&wmi_list,

					struct descriptor_priv,

					list);

	if (priv) {

		*size = priv->size;

		ret = true;

	}

	mutex_unlock(&list_mutex);

	return ret;

}

EXPORT_SYMBOL_GPL(dell_wmi_get_size);



/*

 * Descriptor buffer is 128 byte long and contains:

 *

 *       Name             Offset  Length  Value

 * Vendor Signature          0       4    "DELL"

 * Object Signature          4       4    " WMI"

 * WMI Interface Version     8       4    <version>

 * WMI buffer length        12       4    <length>

 */

static int dell_wmi_descriptor_probe(struct wmi_device *wdev)

{

	union acpi_object *obj = NULL;

	struct descriptor_priv *priv;

	u32 *buffer;

	int ret;



	obj = wmidev_block_query(wdev, 0);

	if (!obj) {

		dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");

		ret = -EIO;

		goto out;

	}



	if (obj->type != ACPI_TYPE_BUFFER) {

		dev_err(&wdev->dev, "Dell descriptor has wrong type\n");

		ret = -EINVAL;

		goto out;

	}



	/* Although it's not technically a failure, this would lead to

	 * unexpected behavior

	 */

	if (obj->buffer.length != 128) {

		dev_err(&wdev->dev,

			"Dell descriptor buffer has unexpected length (%d)\n",

			obj->buffer.length);

		ret = -EINVAL;

		goto out;

	}



	buffer = (u32 *)obj->buffer.pointer;



	if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {

		dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",

			buffer);

		ret = -EINVAL;

		goto out;

	}



	if (buffer[2] != 0 && buffer[2] != 1)

		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",

			(unsigned long) buffer[2]);



	priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),

	GFP_KERNEL);



	priv->interface_version = buffer[2];

	priv->size = buffer[3];

	ret = 0;

	dev_set_drvdata(&wdev->dev, priv);

	mutex_lock(&list_mutex);

	list_add_tail(&priv->list, &wmi_list);

	mutex_unlock(&list_mutex);



	dev_dbg(&wdev->dev, "Detected Dell WMI interface version %lu and buffer size %lu\n",

		(unsigned long) priv->interface_version,

		(unsigned long) priv->size);



out:

	kfree(obj);

	return ret;

}



static int dell_wmi_descriptor_remove(struct wmi_device *wdev)

{

	struct descriptor_priv *priv = dev_get_drvdata(&wdev->dev);



	mutex_lock(&list_mutex);

	list_del(&priv->list);

	mutex_unlock(&list_mutex);

	return 0;

}



static const struct wmi_device_id dell_wmi_descriptor_id_table[] = {

	{ .guid_string = DELL_WMI_DESCRIPTOR_GUID },

	{ },

};



static struct wmi_driver dell_wmi_descriptor_driver = {

	.driver = {

		.name = "dell-wmi-descriptor",

	},

	.probe = dell_wmi_descriptor_probe,

	.remove = dell_wmi_descriptor_remove,

	.id_table = dell_wmi_descriptor_id_table,

};



module_wmi_driver(dell_wmi_descriptor_driver);



MODULE_ALIAS("wmi:" DELL_WMI_DESCRIPTOR_GUID);

MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");

MODULE_DESCRIPTION("Dell WMI descriptor driver");

MODULE_LICENSE("GPL");

drivers/platform/x86/dell-wmi-descriptor.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
/*

 *  Dell WMI descriptor driver

 *

 *  Copyright (c) 2017 Dell Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License version 2 as

 *  published by the Free Software Foundation.

 */



#ifndef _DELL_WMI_DESCRIPTOR_H_

#define _DELL_WMI_DESCRIPTOR_H_



#include <linux/wmi.h>



#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"



bool dell_wmi_get_interface_version(u32 *version);

bool dell_wmi_get_size(u32 *size);



#endif

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