From f9dd82c0ea5588bac5f9ba284c8e609ffd9dfbe5 Mon Sep 17 00:00:00 2001
From: "Darren Hart (VMware)" <dvhart@infradead.org>
Date: Tue, 6 Jun 2017 10:07:32 -0700
Subject: [PATCH] platform/x86: wmi-bmof: New driver to expose embedded Binary WMI MOF metadata
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Git-commit: f9dd82c0ea5588bac5f9ba284c8e609ffd9dfbe5
Patch-mainline: v4.13-rc1
References: FATE#325842
Many laptops (and maybe servers?) have embedded WMI Binary MOF metadata.
We do not yet have open-source tools for processing the data, although
one is in the works thanks to Pali:
https://github.com/pali/bmfdec
There is currently no interface to get the data in the first place. By
exposing it, we facilitate the development of new tools.
This is based on the original work of Andy Lutomirski <luto@kernel.org>,
but contains several modifications in response to various reviews.
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: platform-driver-x86@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/platform/x86/Kconfig | 12 +++
drivers/platform/x86/Makefile | 1
drivers/platform/x86/wmi-bmof.c | 124 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 137 insertions(+)
create mode 100644 drivers/platform/x86/wmi-bmof.c
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -656,6 +656,18 @@ config ACPI_WMI
It is safe to enable this driver even if your DSDT doesn't define
any ACPI-WMI devices.
+config WMI_BMOF
+ tristate "WMI embedded Binary MOF driver"
+ depends on ACPI_WMI
+ default ACPI_WMI
+ ---help---
+ Say Y here if you want to be able to read a firmware-embedded
+ WMI Binary MOF data. Using this requires userspace tools and may be
+ rather tedious.
+
+ To compile this driver as a module, choose M here: the module will
+ be called wmi-bmof.
+
config MSI_WMI
tristate "MSI WMI extras"
depends on ACPI_WMI
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_ACPI_WMI) += wmi.o
obj-$(CONFIG_MSI_WMI) += msi-wmi.o
obj-$(CONFIG_SURFACE3_WMI) += surface3-wmi.o
obj-$(CONFIG_TOPSTAR_LAPTOP) += topstar-laptop.o
+obj-$(CONFIG_WMI_BMOF) += wmi-bmof.o
# toshiba_acpi must link after wmi to ensure that wmi devices are found
# before toshiba_acpi initializes
--- /dev/null
+++ b/drivers/platform/x86/wmi-bmof.c
@@ -0,0 +1,124 @@
+/*
+ * WMI embedded Binary MOF driver
+ *
+ * Copyright (c) 2015 Andrew Lutomirski
+ *
+ * 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/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/wmi.h>
+
+#define WMI_BMOF_GUID "05901221-D566-11D1-B2F0-00A0C9062910"
+
+struct bmof_priv {
+ union acpi_object *bmofdata;
+ struct bin_attribute bmof_bin_attr;
+};
+
+static ssize_t
+read_bmof(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct bmof_priv *priv =
+ container_of(attr, struct bmof_priv, bmof_bin_attr);
+
+ if (off < 0)
+ return -EINVAL;
+
+ if (off >= priv->bmofdata->buffer.length)
+ return 0;
+
+ if (count > priv->bmofdata->buffer.length - off)
+ count = priv->bmofdata->buffer.length - off;
+
+ memcpy(buf, priv->bmofdata->buffer.pointer + off, count);
+ return count;
+}
+
+static int wmi_bmof_probe(struct wmi_device *wdev)
+{
+ struct bmof_priv *priv;
+ int ret;
+
+ priv = devm_kzalloc(&wdev->dev, sizeof(struct bmof_priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ dev_set_drvdata(&wdev->dev, priv);
+
+ priv->bmofdata = wmidev_block_query(wdev, 0);
+ if (!priv->bmofdata) {
+ dev_err(&wdev->dev, "failed to read Binary MOF\n");
+ return -EIO;
+ }
+
+ if (priv->bmofdata->type != ACPI_TYPE_BUFFER) {
+ dev_err(&wdev->dev, "Binary MOF is not a buffer\n");
+ ret = -EIO;
+ goto err_free;
+ }
+
+ sysfs_bin_attr_init(&priv->bmof_bin_attr);
+ priv->bmof_bin_attr.attr.name = "bmof";
+ priv->bmof_bin_attr.attr.mode = 0400;
+ priv->bmof_bin_attr.read = read_bmof;
+ priv->bmof_bin_attr.size = priv->bmofdata->buffer.length;
+
+ ret = sysfs_create_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr);
+ if (ret)
+ goto err_free;
+
+ return 0;
+
+ err_free:
+ kfree(priv->bmofdata);
+ return ret;
+}
+
+static int wmi_bmof_remove(struct wmi_device *wdev)
+{
+ struct bmof_priv *priv = dev_get_drvdata(&wdev->dev);
+
+ sysfs_remove_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr);
+ kfree(priv->bmofdata);
+ return 0;
+}
+
+static const struct wmi_device_id wmi_bmof_id_table[] = {
+ { .guid_string = WMI_BMOF_GUID },
+ { },
+};
+
+static struct wmi_driver wmi_bmof_driver = {
+ .driver = {
+ .name = "wmi-bmof",
+ },
+ .probe = wmi_bmof_probe,
+ .remove = wmi_bmof_remove,
+ .id_table = wmi_bmof_id_table,
+};
+
+module_wmi_driver(wmi_bmof_driver);
+
+MODULE_ALIAS("wmi:" WMI_BMOF_GUID);
+MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
+MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
+MODULE_LICENSE("GPL");