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// SPDX-License-Identifier: GPL-2.0-only
/*
* WMI methods for use with dell-smbios
*
* Copyright (c) 2017 Dell Inc.
*/
#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(input.pointer, 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, const void *context)
{
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 void 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);
}
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_DEVICE_TABLE(wmi, dell_smbios_wmi_id_table);
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