drivers/platform/x86/dell-smbios-wmi.c - third_party/linux - Git at Google

 /*
  *  WMI methods for use with dell-smbios
  *
  *  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.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/dmi.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/uaccess.h>
 #include <linux/wmi.h>
 #include "dell-smbios.h"
 #include "dell-wmi-descriptor.h"

 static DEFINE_MUTEX(call_mutex);
 static DEFINE_MUTEX(list_mutex);
 static int wmi_supported;

 struct misc_bios_flags_structure {
 	struct dmi_header header;
 	u16 flags0;
 } __packed;
 #define FLAG_HAS_ACPI_WMI 0x02

 #define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"

 struct wmi_smbios_priv {
 	struct dell_wmi_smbios_buffer *buf;
 	struct list_head list;
 	struct wmi_device *wdev;
 	struct device *child;
 	u32 req_buf_size;
 };
 static LIST_HEAD(wmi_list);

 static inline struct wmi_smbios_priv *get_first_smbios_priv(void)
 {
 	return list_first_entry_or_null(&wmi_list,
 					struct wmi_smbios_priv,
 					list);
 }

 static int run_smbios_call(struct wmi_device *wdev)
 {
 	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 	struct wmi_smbios_priv *priv;
 	struct acpi_buffer input;
 	union acpi_object *obj;
 	acpi_status status;

 	priv = dev_get_drvdata(&wdev->dev);
 	input.length = priv->req_buf_size - sizeof(u64);
 	input.pointer = &priv->buf->std;

 	dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n",
 		priv->buf->std.cmd_class, priv->buf->std.cmd_select,
 		priv->buf->std.input[0], priv->buf->std.input[1],
 		priv->buf->std.input[2], priv->buf->std.input[3]);

 	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
 	if (ACPI_FAILURE(status))
 		return -EIO;
 	obj = (union acpi_object *)output.pointer;
 	if (obj->type != ACPI_TYPE_BUFFER) {
 		dev_dbg(&wdev->dev, "received type: %d\n", obj->type);
 		if (obj->type == ACPI_TYPE_INTEGER)
 			dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n",
 				obj->integer.value);
 		kfree(output.pointer);
 		return -EIO;
 	}
 	memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length);
 	dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n",
 		priv->buf->std.output[0], priv->buf->std.output[1],
 		priv->buf->std.output[2], priv->buf->std.output[3]);
 	kfree(output.pointer);

 	return 0;
 }

 static int dell_smbios_wmi_call(struct calling_interface_buffer *buffer)
 {
 	struct wmi_smbios_priv *priv;
 	size_t difference;
 	size_t size;
 	int ret;

 	mutex_lock(&call_mutex);
 	priv = get_first_smbios_priv();
 	if (!priv) {
 		ret = -ENODEV;
 		goto out_wmi_call;
 	}

 	size = sizeof(struct calling_interface_buffer);
 	difference = priv->req_buf_size - sizeof(u64) - size;

 	memset(&priv->buf->ext, 0, difference);
 	memcpy(&priv->buf->std, buffer, size);
 	ret = run_smbios_call(priv->wdev);
 	memcpy(buffer, &priv->buf->std, size);
 out_wmi_call:
 	mutex_unlock(&call_mutex);

 	return ret;
 }

 static long dell_smbios_wmi_filter(struct wmi_device *wdev, unsigned int cmd,
 				   struct wmi_ioctl_buffer *arg)
 {
 	struct wmi_smbios_priv *priv;
 	int ret = 0;

 	switch (cmd) {
 	case DELL_WMI_SMBIOS_CMD:
 		mutex_lock(&call_mutex);
 		priv = dev_get_drvdata(&wdev->dev);
 		if (!priv) {
 			ret = -ENODEV;
 			goto fail_smbios_cmd;
 		}
 		memcpy(priv->buf, arg, priv->req_buf_size);
 		if (dell_smbios_call_filter(&wdev->dev, &priv->buf->std)) {
 			dev_err(&wdev->dev, "Invalid call %d/%d:%8x\n",
 				priv->buf->std.cmd_class,
 				priv->buf->std.cmd_select,
 				priv->buf->std.input[0]);
 			ret = -EFAULT;
 			goto fail_smbios_cmd;
 		}
 		ret = run_smbios_call(priv->wdev);
 		if (ret)
 			goto fail_smbios_cmd;
 		memcpy(arg, priv->buf, priv->req_buf_size);
 fail_smbios_cmd:
 		mutex_unlock(&call_mutex);
 		break;
 	default:
 		ret = -ENOIOCTLCMD;
 	}
 	return ret;
 }

 static int dell_smbios_wmi_probe(struct wmi_device *wdev)
 {
 	struct wmi_driver *wdriver =
 		container_of(wdev->dev.driver, struct wmi_driver, driver);
 	struct wmi_smbios_priv *priv;
 	u32 hotfix;
 	int count;
 	int ret;

 	ret = dell_wmi_get_descriptor_valid();
 	if (ret)
 		return ret;

 	priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
 			    GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	/* WMI buffer size will be either 4k or 32k depending on machine */
 	if (!dell_wmi_get_size(&priv->req_buf_size))
 		return -EPROBE_DEFER;

 	/* some SMBIOS calls fail unless BIOS contains hotfix */
 	if (!dell_wmi_get_hotfix(&hotfix))
 		return -EPROBE_DEFER;
 	if (!hotfix) {
 		dev_warn(&wdev->dev,
 			"WMI SMBIOS userspace interface not supported(%u), try upgrading to a newer BIOS\n",
 			hotfix);
 		wdriver->filter_callback = NULL;
 	}

 	/* add in the length object we will use internally with ioctl */
 	priv->req_buf_size += sizeof(u64);
 	ret = set_required_buffer_size(wdev, priv->req_buf_size);
 	if (ret)
 		return ret;

 	count = get_order(priv->req_buf_size);
 	priv->buf = (void *)__get_free_pages(GFP_KERNEL, count);
 	if (!priv->buf)
 		return -ENOMEM;

 	/* ID is used by dell-smbios to set priority of drivers */
 	wdev->dev.id = 1;
 	ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call);
 	if (ret)
 		goto fail_register;

 	priv->wdev = wdev;
 	dev_set_drvdata(&wdev->dev, priv);
 	mutex_lock(&list_mutex);
 	list_add_tail(&priv->list, &wmi_list);
 	mutex_unlock(&list_mutex);

 	return 0;

 fail_register:
 	free_pages((unsigned long)priv->buf, count);
 	return ret;
 }

 static int dell_smbios_wmi_remove(struct wmi_device *wdev)
 {
 	struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev);
 	int count;

 	mutex_lock(&call_mutex);
 	mutex_lock(&list_mutex);
 	list_del(&priv->list);
 	mutex_unlock(&list_mutex);
 	dell_smbios_unregister_device(&wdev->dev);
 	count = get_order(priv->req_buf_size);
 	free_pages((unsigned long)priv->buf, count);
 	mutex_unlock(&call_mutex);
 	return 0;
 }

 static const struct wmi_device_id dell_smbios_wmi_id_table[] = {
 	{ .guid_string = DELL_WMI_SMBIOS_GUID },
 	{ },
 };

 static void parse_b1_table(const struct dmi_header *dm)
 {
 	struct misc_bios_flags_structure *flags =
 	container_of(dm, struct misc_bios_flags_structure, header);

 	/* 4 bytes header, 8 bytes flags */
 	if (dm->length < 12)
 		return;
 	if (dm->handle != 0xb100)
 		return;
 	if ((flags->flags0 & FLAG_HAS_ACPI_WMI))
 		wmi_supported = 1;
 }

 static void find_b1(const struct dmi_header *dm, void *dummy)
 {
 	switch (dm->type) {
 	case 0xb1: /* misc bios flags */
 		parse_b1_table(dm);
 		break;
 	}
 }

 static struct wmi_driver dell_smbios_wmi_driver = {
 	.driver = {
 		.name = "dell-smbios",
 	},
 	.probe = dell_smbios_wmi_probe,
 	.remove = dell_smbios_wmi_remove,
 	.id_table = dell_smbios_wmi_id_table,
 	.filter_callback = dell_smbios_wmi_filter,
 };

 int init_dell_smbios_wmi(void)
 {
 	dmi_walk(find_b1, NULL);

 	if (!wmi_supported)
 		return -ENODEV;

 	return wmi_driver_register(&dell_smbios_wmi_driver);
 }

 void exit_dell_smbios_wmi(void)
 {
 	if (wmi_supported)
 		wmi_driver_unregister(&dell_smbios_wmi_driver);
 }

 MODULE_ALIAS("wmi:" DELL_WMI_SMBIOS_GUID);
	/*
	* WMI methods for use with dell-smbios
	*
	* 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.
	*/
	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/dmi.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/uaccess.h>
	#include <linux/wmi.h>
	#include "dell-smbios.h"
	#include "dell-wmi-descriptor.h"

	static DEFINE_MUTEX(call_mutex);
	static DEFINE_MUTEX(list_mutex);
	static int wmi_supported;

	struct misc_bios_flags_structure {
	struct dmi_header header;
	u16 flags0;
	} __packed;
	#define FLAG_HAS_ACPI_WMI 0x02

	#define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"

	struct wmi_smbios_priv {
	struct dell_wmi_smbios_buffer *buf;
	struct list_head list;
	struct wmi_device *wdev;
	struct device *child;
	u32 req_buf_size;
	};
	static LIST_HEAD(wmi_list);

	static inline struct wmi_smbios_priv *get_first_smbios_priv(void)
	{
	return list_first_entry_or_null(&wmi_list,
	struct wmi_smbios_priv,
	list);
	}

	static int run_smbios_call(struct wmi_device *wdev)
	{
	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
	struct wmi_smbios_priv *priv;
	struct acpi_buffer input;
	union acpi_object *obj;
	acpi_status status;

	priv = dev_get_drvdata(&wdev->dev);
	input.length = priv->req_buf_size - sizeof(u64);
	input.pointer = &priv->buf->std;

	dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n",
	priv->buf->std.cmd_class, priv->buf->std.cmd_select,
	priv->buf->std.input[0], priv->buf->std.input[1],
	priv->buf->std.input[2], priv->buf->std.input[3]);

	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
	if (ACPI_FAILURE(status))
	return -EIO;
	obj = (union acpi_object *)output.pointer;
	if (obj->type != ACPI_TYPE_BUFFER) {
	dev_dbg(&wdev->dev, "received type: %d\n", obj->type);
	if (obj->type == ACPI_TYPE_INTEGER)
	dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n",
	obj->integer.value);
	kfree(output.pointer);
	return -EIO;
	}
	memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length);
	dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n",
	priv->buf->std.output[0], priv->buf->std.output[1],
	priv->buf->std.output[2], priv->buf->std.output[3]);
	kfree(output.pointer);

	return 0;
	}

	static int dell_smbios_wmi_call(struct calling_interface_buffer *buffer)
	{
	struct wmi_smbios_priv *priv;
	size_t difference;
	size_t size;
	int ret;

	mutex_lock(&call_mutex);
	priv = get_first_smbios_priv();
	if (!priv) {
	ret = -ENODEV;
	goto out_wmi_call;
	}

	size = sizeof(struct calling_interface_buffer);
	difference = priv->req_buf_size - sizeof(u64) - size;

	memset(&priv->buf->ext, 0, difference);
	memcpy(&priv->buf->std, buffer, size);
	ret = run_smbios_call(priv->wdev);
	memcpy(buffer, &priv->buf->std, size);
	out_wmi_call:
	mutex_unlock(&call_mutex);

	return ret;
	}

	static long dell_smbios_wmi_filter(struct wmi_device *wdev, unsigned int cmd,
	struct wmi_ioctl_buffer *arg)
	{
	struct wmi_smbios_priv *priv;
	int ret = 0;

	switch (cmd) {
	case DELL_WMI_SMBIOS_CMD:
	mutex_lock(&call_mutex);
	priv = dev_get_drvdata(&wdev->dev);
	if (!priv) {
	ret = -ENODEV;
	goto fail_smbios_cmd;
	}
	memcpy(priv->buf, arg, priv->req_buf_size);
	if (dell_smbios_call_filter(&wdev->dev, &priv->buf->std)) {
	dev_err(&wdev->dev, "Invalid call %d/%d:%8x\n",
	priv->buf->std.cmd_class,
	priv->buf->std.cmd_select,
	priv->buf->std.input[0]);
	ret = -EFAULT;
	goto fail_smbios_cmd;
	}
	ret = run_smbios_call(priv->wdev);
	if (ret)
	goto fail_smbios_cmd;
	memcpy(arg, priv->buf, priv->req_buf_size);
	fail_smbios_cmd:
	mutex_unlock(&call_mutex);
	break;
	default:
	ret = -ENOIOCTLCMD;
	}
	return ret;
	}

	static int dell_smbios_wmi_probe(struct wmi_device *wdev)
	{
	struct wmi_driver *wdriver =
	container_of(wdev->dev.driver, struct wmi_driver, driver);
	struct wmi_smbios_priv *priv;
	u32 hotfix;
	int count;
	int ret;

	ret = dell_wmi_get_descriptor_valid();
	if (ret)
	return ret;

	priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
	GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	/* WMI buffer size will be either 4k or 32k depending on machine */
	if (!dell_wmi_get_size(&priv->req_buf_size))
	return -EPROBE_DEFER;

	/* some SMBIOS calls fail unless BIOS contains hotfix */
	if (!dell_wmi_get_hotfix(&hotfix))
	return -EPROBE_DEFER;
	if (!hotfix) {
	dev_warn(&wdev->dev,
	"WMI SMBIOS userspace interface not supported(%u), try upgrading to a newer BIOS\n",
	hotfix);
	wdriver->filter_callback = NULL;
	}

	/* add in the length object we will use internally with ioctl */
	priv->req_buf_size += sizeof(u64);
	ret = set_required_buffer_size(wdev, priv->req_buf_size);
	if (ret)
	return ret;

	count = get_order(priv->req_buf_size);
	priv->buf = (void *)__get_free_pages(GFP_KERNEL, count);
	if (!priv->buf)
	return -ENOMEM;

	/* ID is used by dell-smbios to set priority of drivers */
	wdev->dev.id = 1;
	ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call);
	if (ret)
	goto fail_register;

	priv->wdev = wdev;
	dev_set_drvdata(&wdev->dev, priv);
	mutex_lock(&list_mutex);
	list_add_tail(&priv->list, &wmi_list);
	mutex_unlock(&list_mutex);

	return 0;

	fail_register:
	free_pages((unsigned long)priv->buf, count);
	return ret;
	}

	static int dell_smbios_wmi_remove(struct wmi_device *wdev)
	{
	struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev);
	int count;

	mutex_lock(&call_mutex);
	mutex_lock(&list_mutex);
	list_del(&priv->list);
	mutex_unlock(&list_mutex);
	dell_smbios_unregister_device(&wdev->dev);
	count = get_order(priv->req_buf_size);
	free_pages((unsigned long)priv->buf, count);
	mutex_unlock(&call_mutex);
	return 0;
	}

	static const struct wmi_device_id dell_smbios_wmi_id_table[] = {
	{ .guid_string = DELL_WMI_SMBIOS_GUID },
	{ },
	};

	static void parse_b1_table(const struct dmi_header *dm)
	{
	struct misc_bios_flags_structure *flags =
	container_of(dm, struct misc_bios_flags_structure, header);

	/* 4 bytes header, 8 bytes flags */
	if (dm->length < 12)
	return;
	if (dm->handle != 0xb100)
	return;
	if ((flags->flags0 & FLAG_HAS_ACPI_WMI))
	wmi_supported = 1;
	}

	static void find_b1(const struct dmi_header dm, void dummy)
	{
	switch (dm->type) {
	case 0xb1: /* misc bios flags */
	parse_b1_table(dm);
	break;
	}
	}

	static struct wmi_driver dell_smbios_wmi_driver = {
	.driver = {
	.name = "dell-smbios",
	},
	.probe = dell_smbios_wmi_probe,
	.remove = dell_smbios_wmi_remove,
	.id_table = dell_smbios_wmi_id_table,
	.filter_callback = dell_smbios_wmi_filter,
	};

	int init_dell_smbios_wmi(void)
	{
	dmi_walk(find_b1, NULL);

	if (!wmi_supported)
	return -ENODEV;

	return wmi_driver_register(&dell_smbios_wmi_driver);
	}

	void exit_dell_smbios_wmi(void)
	{
	if (wmi_supported)
	wmi_driver_unregister(&dell_smbios_wmi_driver);
	}

	MODULE_ALIAS("wmi:" DELL_WMI_SMBIOS_GUID);