[PATCH 04/12] platform/x86: dell-smbios: Switch to a WMI-ACPI interface

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The driver currently uses an SMI interface which grants direct access
to physical memory to the platform via a pointer.

Changing this to operate over WMI-ACPI will use an ACPI OperationRegion
for a buffer of data storage when platform calls are performed.

This is a safer approach to use in kernel drivers as the platform will
only have access to that OperationRegion.

As a result, this change removes the dependency on this driver on the
dcdbas kernel module.

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
---
 drivers/platform/x86/Kconfig       |  8 ++--
 drivers/platform/x86/dell-smbios.c | 76 ++++++++++++++++++++++++++------------
 drivers/platform/x86/dell-smbios.h | 11 +++---
 3 files changed, 63 insertions(+), 32 deletions(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 9e52f05daa2e..81d61c0f4ef8 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -92,13 +92,13 @@ config ASUS_LAPTOP
 	  If you have an ACPI-compatible ASUS laptop, say Y or M here.
 
 config DELL_SMBIOS
-	tristate
-	select DCDBAS
+	tristate "Dell WMI SMBIOS calling interface"
+	depends on ACPI_WMI
 	---help---
 	This module provides common functions for kernel modules using
-	Dell SMBIOS.
+	Dell SMBIOS over ACPI-WMI.
 
-	If you have a Dell laptop, say Y or M here.
+	If you have a Dell computer, say Y or M here.
 
 config DELL_LAPTOP
 	tristate "Dell Laptop Extras"
diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c
index e9b1ca07c872..c06262a89169 100644
--- a/drivers/platform/x86/dell-smbios.c
+++ b/drivers/platform/x86/dell-smbios.c
@@ -4,6 +4,7 @@
  *  Copyright (c) Red Hat <mjg@xxxxxxxxxx>
  *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>
  *  Copyright (c) 2014 Pali Rohár <pali.rohar@xxxxxxxxx>
+ *  Copyright (c) 2017 Dell Inc.
  *
  *  Based on documentation in the libsmbios package:
  *  Copyright (C) 2005-2014 Dell Inc.
@@ -18,13 +19,12 @@
 #include <linux/module.h>
 #include <linux/dmi.h>
 #include <linux/err.h>
-#include <linux/gfp.h>
 #include <linux/mutex.h>
-#include <linux/slab.h>
-#include <linux/io.h>
-#include "../../firmware/dcdbas.h"
+#include <linux/wmi.h>
 #include "dell-smbios.h"
 
+#define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"
+
 struct calling_interface_structure {
 	struct dmi_header header;
 	u16 cmdIOAddress;
@@ -76,20 +76,39 @@ void dell_smbios_release_buffer(void)
 }
 EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);
 
-void dell_smbios_send_request(int class, int select)
+int run_wmi_smbios_call(struct calling_interface_buffer *buffer)
 {
-	struct smi_cmd command;
+	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct acpi_buffer input;
+	union acpi_object *obj;
+	acpi_status status;
+
+	input.length = sizeof(struct calling_interface_buffer);
+	input.pointer = buffer;
+
+	status = wmi_evaluate_method(DELL_WMI_SMBIOS_GUID,
+				     0, 1, &input, &output);
+	if (ACPI_FAILURE(status)) {
+		pr_err("%x/%x [%x,%x,%x,%x] call failed\n",
+			buffer->class, buffer->select, buffer->input[0],
+			buffer->input[1], buffer->input[2], buffer->input[3]);
+			return -EIO;
+	}
+	obj = (union acpi_object *)output.pointer;
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		pr_err("invalid type : %d\n", obj->type);
+		return -EIO;
+	}
+	memcpy(buffer, obj->buffer.pointer, input.length);
 
-	command.magic = SMI_CMD_MAGIC;
-	command.command_address = da_command_address;
-	command.command_code = da_command_code;
-	command.ebx = virt_to_phys(buffer);
-	command.ecx = 0x42534931;
+	return 0;
+}
 
+void dell_smbios_send_request(int class, int select)
+{
 	buffer->class = class;
 	buffer->select = select;
-
-	dcdbas_smi_request(&command);
+	run_wmi_smbios_call(buffer);
 }
 EXPORT_SYMBOL_GPL(dell_smbios_send_request);
 
@@ -170,7 +189,7 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 	}
 }
 
-static int __init dell_smbios_init(void)
+static int dell_smbios_probe(struct wmi_device *wdev)
 {
 	int ret;
 
@@ -181,11 +200,7 @@ static int __init dell_smbios_init(void)
 		return -ENODEV;
 	}
 
-	/*
-	 * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
-	 * is passed to SMI handler.
-	 */
-	buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
+	buffer = (void *)__get_free_page(GFP_KERNEL);
 	if (!buffer) {
 		ret = -ENOMEM;
 		goto fail_buffer;
@@ -198,17 +213,32 @@ static int __init dell_smbios_init(void)
 	return ret;
 }
 
-static void __exit dell_smbios_exit(void)
+static int dell_smbios_remove(struct wmi_device *wdev)
 {
 	kfree(da_tokens);
 	free_page((unsigned long)buffer);
+	return 0;
 }
 
-subsys_initcall(dell_smbios_init);
-module_exit(dell_smbios_exit);
+static const struct wmi_device_id dell_smbios_id_table[] = {
+	{ .guid_string = DELL_WMI_SMBIOS_GUID },
+	{ },
+};
+
+static struct wmi_driver dell_smbios_driver = {
+	.driver = {
+		.name = "dell-smbios",
+	},
+	.probe = dell_smbios_probe,
+	.remove = dell_smbios_remove,
+	.id_table = dell_smbios_id_table,
+};
+module_wmi_driver(dell_smbios_driver);
+
 
 MODULE_AUTHOR("Matthew Garrett <mjg@xxxxxxxxxx>");
 MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>");
 MODULE_AUTHOR("Pali Rohár <pali.rohar@xxxxxxxxx>");
-MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
+MODULE_AUTHOR("Mario Limonciello <mario.limonciello@xxxxxxxx>");
+MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS over WMI");
 MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/dell-smbios.h b/drivers/platform/x86/dell-smbios.h
index 45cbc2292cd3..e1e29697b362 100644
--- a/drivers/platform/x86/dell-smbios.h
+++ b/drivers/platform/x86/dell-smbios.h
@@ -4,6 +4,7 @@
  *  Copyright (c) Red Hat <mjg@xxxxxxxxxx>
  *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@xxxxxxxxx>
  *  Copyright (c) 2014 Pali Rohár <pali.rohar@xxxxxxxxx>
+ *  Copyright (c) 2017 Dell Inc.
  *
  *  Based on documentation in the libsmbios package:
  *  Copyright (C) 2005-2014 Dell Inc.
@@ -18,14 +19,14 @@
 
 struct notifier_block;
 
-/* This structure will be modified by the firmware when we enter
- * system management mode, hence the volatiles */
-
 struct calling_interface_buffer {
 	u16 class;
 	u16 select;
-	volatile u32 input[4];
-	volatile u32 output[4];
+	u32 input[4];
+	u32 output[4];
+	u32 argattrib;
+	u32 blength;
+	u8 data[4052];
 } __packed;
 
 struct calling_interface_token {
-- 
2.14.1




[Index of Archives]     [Linux Kernel Development]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux