![Mario Limonciello](/assets/img/avatar_default.png)
The Dell SMBIOS WMI interface will fail for some more complex calls unless a WMI hotfix has been included. Most platforms have this fix available in a maintenance BIOS release. In the case the driver is loaded on a platform without this fix, disable the userspace interface. A hotfix indicator is present in the dell-wmi-descriptor that represents whether or not more complex calls will work properly. "Simple" calls such as those used by dell-laptop and dell-wmi will continue to work properly so dell-smbios-wmi should not be blocked from binding and being used as the dell-smbios dispatcher. Suggested-by: Girish Prakash <girish.prakash@dell.com> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
214 lines
5 KiB
C
214 lines
5 KiB
C
/*
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* Dell WMI descriptor driver
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*
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* Copyright (C) 2017 Dell Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/acpi.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/wmi.h>
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#include "dell-wmi-descriptor.h"
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#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
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struct descriptor_priv {
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struct list_head list;
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u32 interface_version;
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u32 size;
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u32 hotfix;
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};
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static int descriptor_valid = -EPROBE_DEFER;
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static LIST_HEAD(wmi_list);
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static DEFINE_MUTEX(list_mutex);
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int dell_wmi_get_descriptor_valid(void)
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{
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if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
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return -ENODEV;
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return descriptor_valid;
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}
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EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
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bool dell_wmi_get_interface_version(u32 *version)
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{
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struct descriptor_priv *priv;
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bool ret = false;
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mutex_lock(&list_mutex);
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priv = list_first_entry_or_null(&wmi_list,
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struct descriptor_priv,
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list);
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if (priv) {
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*version = priv->interface_version;
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ret = true;
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}
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mutex_unlock(&list_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dell_wmi_get_interface_version);
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bool dell_wmi_get_size(u32 *size)
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{
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struct descriptor_priv *priv;
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bool ret = false;
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mutex_lock(&list_mutex);
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priv = list_first_entry_or_null(&wmi_list,
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struct descriptor_priv,
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list);
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if (priv) {
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*size = priv->size;
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ret = true;
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}
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mutex_unlock(&list_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dell_wmi_get_size);
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bool dell_wmi_get_hotfix(u32 *hotfix)
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{
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struct descriptor_priv *priv;
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bool ret = false;
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mutex_lock(&list_mutex);
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priv = list_first_entry_or_null(&wmi_list,
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struct descriptor_priv,
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list);
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if (priv) {
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*hotfix = priv->hotfix;
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ret = true;
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}
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mutex_unlock(&list_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dell_wmi_get_hotfix);
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/*
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* Descriptor buffer is 128 byte long and contains:
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*
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* Name Offset Length Value
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* Vendor Signature 0 4 "DELL"
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* Object Signature 4 4 " WMI"
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* WMI Interface Version 8 4 <version>
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* WMI buffer length 12 4 <length>
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* WMI hotfix number 16 4 <hotfix>
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*/
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static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
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{
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union acpi_object *obj = NULL;
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struct descriptor_priv *priv;
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u32 *buffer;
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int ret;
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obj = wmidev_block_query(wdev, 0);
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if (!obj) {
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dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");
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ret = -EIO;
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goto out;
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}
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if (obj->type != ACPI_TYPE_BUFFER) {
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dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
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ret = -EINVAL;
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descriptor_valid = ret;
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goto out;
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}
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/* Although it's not technically a failure, this would lead to
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* unexpected behavior
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*/
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if (obj->buffer.length != 128) {
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dev_err(&wdev->dev,
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"Dell descriptor buffer has unexpected length (%d)\n",
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obj->buffer.length);
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ret = -EINVAL;
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descriptor_valid = ret;
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goto out;
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}
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buffer = (u32 *)obj->buffer.pointer;
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if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
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dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
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buffer);
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ret = -EINVAL;
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descriptor_valid = ret;
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goto out;
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}
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descriptor_valid = 0;
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if (buffer[2] != 0 && buffer[2] != 1)
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dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
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(unsigned long) buffer[2]);
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priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),
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GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto out;
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}
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priv->interface_version = buffer[2];
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priv->size = buffer[3];
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priv->hotfix = buffer[4];
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ret = 0;
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dev_set_drvdata(&wdev->dev, priv);
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mutex_lock(&list_mutex);
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list_add_tail(&priv->list, &wmi_list);
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mutex_unlock(&list_mutex);
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dev_dbg(&wdev->dev, "Detected Dell WMI interface version %lu, buffer size %lu, hotfix %lu\n",
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(unsigned long) priv->interface_version,
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(unsigned long) priv->size,
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(unsigned long) priv->hotfix);
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out:
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kfree(obj);
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return ret;
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}
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static int dell_wmi_descriptor_remove(struct wmi_device *wdev)
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{
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struct descriptor_priv *priv = dev_get_drvdata(&wdev->dev);
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mutex_lock(&list_mutex);
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list_del(&priv->list);
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mutex_unlock(&list_mutex);
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return 0;
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}
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static const struct wmi_device_id dell_wmi_descriptor_id_table[] = {
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{ .guid_string = DELL_WMI_DESCRIPTOR_GUID },
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{ },
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};
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static struct wmi_driver dell_wmi_descriptor_driver = {
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.driver = {
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.name = "dell-wmi-descriptor",
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},
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.probe = dell_wmi_descriptor_probe,
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.remove = dell_wmi_descriptor_remove,
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.id_table = dell_wmi_descriptor_id_table,
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};
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module_wmi_driver(dell_wmi_descriptor_driver);
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MODULE_ALIAS("wmi:" DELL_WMI_DESCRIPTOR_GUID);
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MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
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MODULE_DESCRIPTION("Dell WMI descriptor driver");
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MODULE_LICENSE("GPL");
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