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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: Mario Limonciello <mario.limonciello@dell.com> Reviewed-by: Edward O'Callaghan <quasisec@google.com> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
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Mario Limonciello
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Darren Hart (VMware)
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Nov 3, 2017
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,170 @@ | ||
| /* | ||
| * 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; | ||
|
|
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| 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]); | ||
|
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| priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv), | ||
| GFP_KERNEL); | ||
|
|
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| 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); | ||
|
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| 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; | ||
| } | ||
|
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| static int dell_wmi_descriptor_remove(struct wmi_device *wdev) | ||
| { | ||
| struct descriptor_priv *priv = dev_get_drvdata(&wdev->dev); | ||
|
|
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| mutex_lock(&list_mutex); | ||
| list_del(&priv->list); | ||
| mutex_unlock(&list_mutex); | ||
| return 0; | ||
| } | ||
|
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||
| static const struct wmi_device_id dell_wmi_descriptor_id_table[] = { | ||
| { .guid_string = DELL_WMI_DESCRIPTOR_GUID }, | ||
| { }, | ||
| }; | ||
|
|
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| 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, | ||
| }; | ||
|
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| module_wmi_driver(dell_wmi_descriptor_driver); | ||
|
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| MODULE_ALIAS("wmi:" DELL_WMI_DESCRIPTOR_GUID); | ||
| MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>"); | ||
| MODULE_DESCRIPTION("Dell WMI descriptor driver"); | ||
| MODULE_LICENSE("GPL"); |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,21 @@ | ||
| /* | ||
| * 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_ | ||
|
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| #include <linux/wmi.h> | ||
|
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| #define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492" | ||
|
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| bool dell_wmi_get_interface_version(u32 *version); | ||
| bool dell_wmi_get_size(u32 *size); | ||
|
|
||
| #endif |
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