Merge tag 'platform-drivers-x86-v4.15-1' of git://git.infradead.org/linux-platform-drivers-x86

Pull x86 platform driver updates from Andy Shevchenko:
 "Here is the collected material against Platform Drivers x86 subsystem.
  It's rather bit busy cycle for PDx86, mostly due to Dell SMBIOS driver
  activity

  For this cycle we have quite an update for the Dell SMBIOS driver
  including WMI work to provide an interface for SMBIOS tokens via sysfs
  and WMI support for 2017+ Dell laptop models. SMM dispatcher code is
  split into a separate driver followed by a new WMI dispatcher. The
  latter provides a character device interface to user space.

  The git history also contains a merge of immutable branch from Wolfram
  Sang in order to apply a dependent fix to the Intel CherryTrail
  Battery Management driver.

  Other Intel drivers got a lot of cleanups. The Turbo Boost Max 3.0
  support is added for Intel Skylake.

  Peaq WMI hotkeys driver gets its own maintainer and white list of
  supported models.

  Silead DMI is expanded to support few additional platforms.

  Tablet mode via GMMS ACPI method is added to support some ThinkPad
  tablets.

  new driver:
   - Add driver to force WMI Thunderbolt controller power status

  asus-wmi:
   -  Add lightbar led support

  dell-laptop:
   -  Allocate buffer before rfkill use

  dell-smbios:
   -  fix string overflow
   -  Add filtering support
   -  Introduce dispatcher for SMM calls
   -  Add a sysfs interface for SMBIOS tokens
   -  only run if proper oem string is detected
   -  Prefix class/select with cmd_
   -  Add pr_fmt definition to driver

  dell-smbios-smm:
   -  test for WSMT

  dell-smbios-wmi:
   -  release mutex lock on WMI call failure
   -  introduce userspace interface
   -  Add new WMI dispatcher driver

  dell-smo8800:
   -  remove redundant assignments to byte_data

  dell-wmi:
   -  don't check length returned
   -  clean up wmi descriptor check
   -  increase severity of some failures
   -  Do not match on descriptor GUID modalias
   -  Label driver as handling notifications

  dell-*wmi*:
   -  Relay failed initial probe to dependent drivers

  dell-wmi-descriptor:
   -  check if memory was allocated
   -  split WMI descriptor into it's own driver

  fujitsu-laptop:
   -  Fix radio LED detection
   -  Don't oops when FUJ02E3 is not presnt

  hp_accel:
   -  Add quirk for HP ProBook 440 G4

  hp-wmi:
   -  Fix tablet mode detection for convertibles

  ideapad-laptop:
   -  Add Lenovo Yoga 920-13IKB to no_hw_rfkill dmi list

  intel_cht_int33fe:
   -  Update fusb302 type string, add properties
   -  make a couple of local functions static
   -  Work around BIOS bug on some devices

  intel-hid:
   -  Power button suspend on Dell Latitude 7275

  intel_ips:
   -  Convert timers to use timer_setup()
   -  Remove FSF address from GPL notice
   -  Remove unneeded fields and label
   -  Keep pointer to struct device
   -  Use PCI_VDEVICE() macro
   -  Switch to new PCI IRQ allocation API
   -  Simplify error handling via devres API

  intel_pmc_ipc:
   -  Revert Use MFD framework to create dependent devices
   -  Use MFD framework to create dependent devices
   -  Use spin_lock to protect GCR updates
   -  Use devm_* calls in driver probe function

  intel_punit_ipc:
   -  Fix resource ioremap warning

  intel_telemetry:
   -  Remove useless default in Kconfig
   -  Add needed inclusion
   -  cleanup redundant headers
   -  Fix typos
   -  Fix load failure info

  intel_telemetry_debugfs:
   -  Use standard ARRAY_SIZE() macro

  intel_turbo_max_3:
   -  Add Skylake platform

  intel-wmi-thunderbolt:
   -  Silence error cases

  mlx-platform:
   -  make a couple of structures static

  peaq_wmi:
   -  Fix missing terminating entry for peaq_dmi_table

  peaq-wmi:
   -  Remove unnecessary checks from peaq_wmi_exit
   -  Add DMI check before binding to the WMI interface
   -  Revert Blacklist Lenovo ideapad 700-15ISK
   -  Blacklist Lenovo ideapad 700-15ISK

  silead_dmi:
   -  Add silead, home-button property to some tablets
   -  Add entry for the Digma e200 tablet
   -  Fix GP-electronic T701 entry
   -  Add entry for the Chuwi Hi8 Pro tablet

  sony-laptop:
   -  Drop variable assignment in sony_nc_setup_rfkill()
   -  Fix error handling in sony_nc_setup_rfkill()

  thinkpad_acpi:
   -  Implement tablet mode using GMMS method

  tools/wmi:
   -  add a sample for dell smbios communication over WMI

  wmi:
   -  release mutex on module acquistion failure
   -  create userspace interface for drivers
   -  Don't allow drivers to get each other's GUIDs
   -  Add new method wmidev_evaluate_method
   -  Destroy on cleanup rather than unregister
   -  Cleanup exit routine in reverse order of init
   -  Sort include list"

* tag 'platform-drivers-x86-v4.15-1' of git://git.infradead.org/linux-platform-drivers-x86: (74 commits)
  platform/x86: silead_dmi: Add silead, home-button property to some tablets
  platform/x86: dell-laptop: Allocate buffer before rfkill use
  platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
  platform/x86: dell-wmi-descriptor: check if memory was allocated
  platform/x86: Revert intel_pmc_ipc: Use MFD framework to create dependent devices
  platform/x86: dell-smbios-wmi: release mutex lock on WMI call failure
  platform/x86: wmi: release mutex on module acquistion failure
  platform/x86: dell-smbios: fix string overflow
  platform/x86: intel_pmc_ipc: Use MFD framework to create dependent devices
  platform/x86: intel_punit_ipc: Fix resource ioremap warning
  platform/x86: dell-smo8800: remove redundant assignments to byte_data
  platform/x86: hp-wmi: Fix tablet mode detection for convertibles
  platform/x86: intel_ips: Convert timers to use timer_setup()
  platform/x86: sony-laptop: Drop variable assignment in sony_nc_setup_rfkill()
  platform/x86: sony-laptop: Fix error handling in sony_nc_setup_rfkill()
  tools/wmi: add a sample for dell smbios communication over WMI
  platform/x86: dell-smbios-wmi: introduce userspace interface
  platform/x86: wmi: create userspace interface for drivers
  platform/x86: dell-smbios: Add filtering support
  platform/x86: dell-smbios-smm: test for WSMT
  ...

1 files changed, 463 insertions, 49 deletions

diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c
index 0a5723468bff..6a60db515bda 100644
--- a/drivers/platform/x86/dell-smbios.c
+++ b/drivers/platform/x86/dell-smbios.c
@@ -12,33 +12,119 @@
  *  it under the terms of the GNU General Public License version 2 as
  *  published by the Free Software Foundation.
  */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/capability.h>
 #include <linux/dmi.h>
 #include <linux/err.h>
-#include <linux/gfp.h>
 #include <linux/mutex.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
-#include <linux/io.h>
-#include "../../firmware/dcdbas.h"
 #include "dell-smbios.h"
 
-struct calling_interface_structure {
-	struct dmi_header header;
-	u16 cmdIOAddress;
-	u8 cmdIOCode;
-	u32 supportedCmds;
-	struct calling_interface_token tokens[];
-} __packed;
-
-static struct calling_interface_buffer *buffer;
-static DEFINE_MUTEX(buffer_mutex);
-
-static int da_command_address;
-static int da_command_code;
+static u32 da_supported_commands;
 static int da_num_tokens;
+static struct platform_device *platform_device;
 static struct calling_interface_token *da_tokens;
+static struct device_attribute *token_location_attrs;
+static struct device_attribute *token_value_attrs;
+static struct attribute **token_attrs;
+static DEFINE_MUTEX(smbios_mutex);
+
+struct smbios_device {
+	struct list_head list;
+	struct device *device;
+	int (*call_fn)(struct calling_interface_buffer *);
+};
+
+struct smbios_call {
+	u32 need_capability;
+	int cmd_class;
+	int cmd_select;
+};
+
+/* calls that are whitelisted for given capabilities */
+static struct smbios_call call_whitelist[] = {
+	/* generally tokens are allowed, but may be further filtered or
+	 * restricted by token blacklist or whitelist
+	 */
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_READ,	SELECT_TOKEN_STD},
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_READ,	SELECT_TOKEN_AC},
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_READ,	SELECT_TOKEN_BAT},
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_WRITE,	SELECT_TOKEN_STD},
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_WRITE,	SELECT_TOKEN_AC},
+	{CAP_SYS_ADMIN,	CLASS_TOKEN_WRITE,	SELECT_TOKEN_BAT},
+	/* used by userspace: fwupdate */
+	{CAP_SYS_ADMIN, CLASS_ADMIN_PROP,	SELECT_ADMIN_PROP},
+	/* used by userspace: fwupd */
+	{CAP_SYS_ADMIN,	CLASS_INFO,		SELECT_DOCK},
+	{CAP_SYS_ADMIN,	CLASS_FLASH_INTERFACE,	SELECT_FLASH_INTERFACE},
+};
+
+/* calls that are explicitly blacklisted */
+static struct smbios_call call_blacklist[] = {
+	{0x0000, 01, 07}, /* manufacturing use */
+	{0x0000, 06, 05}, /* manufacturing use */
+	{0x0000, 11, 03}, /* write once */
+	{0x0000, 11, 07}, /* write once */
+	{0x0000, 11, 11}, /* write once */
+	{0x0000, 19, -1}, /* diagnostics */
+	/* handled by kernel: dell-laptop */
+	{0x0000, CLASS_INFO, SELECT_RFKILL},
+	{0x0000, CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT},
+};
+
+struct token_range {
+	u32 need_capability;
+	u16 min;
+	u16 max;
+};
+
+/* tokens that are whitelisted for given capabilities */
+static struct token_range token_whitelist[] = {
+	/* used by userspace: fwupdate */
+	{CAP_SYS_ADMIN,	CAPSULE_EN_TOKEN,	CAPSULE_DIS_TOKEN},
+	/* can indicate to userspace that WMI is needed */
+	{0x0000,	WSMT_EN_TOKEN,		WSMT_DIS_TOKEN}
+};
+
+/* tokens that are explicitly blacklisted */
+static struct token_range token_blacklist[] = {
+	{0x0000, 0x0058, 0x0059}, /* ME use */
+	{0x0000, 0x00CD, 0x00D0}, /* raid shadow copy */
+	{0x0000, 0x013A, 0x01FF}, /* sata shadow copy */
+	{0x0000, 0x0175, 0x0176}, /* write once */
+	{0x0000, 0x0195, 0x0197}, /* diagnostics */
+	{0x0000, 0x01DC, 0x01DD}, /* manufacturing use */
+	{0x0000, 0x027D, 0x0284}, /* diagnostics */
+	{0x0000, 0x02E3, 0x02E3}, /* manufacturing use */
+	{0x0000, 0x02FF, 0x02FF}, /* manufacturing use */
+	{0x0000, 0x0300, 0x0302}, /* manufacturing use */
+	{0x0000, 0x0325, 0x0326}, /* manufacturing use */
+	{0x0000, 0x0332, 0x0335}, /* fan control */
+	{0x0000, 0x0350, 0x0350}, /* manufacturing use */
+	{0x0000, 0x0363, 0x0363}, /* manufacturing use */
+	{0x0000, 0x0368, 0x0368}, /* manufacturing use */
+	{0x0000, 0x03F6, 0x03F7}, /* manufacturing use */
+	{0x0000, 0x049E, 0x049F}, /* manufacturing use */
+	{0x0000, 0x04A0, 0x04A3}, /* disagnostics */
+	{0x0000, 0x04E6, 0x04E7}, /* manufacturing use */
+	{0x0000, 0x4000, 0x7FFF}, /* internal BIOS use */
+	{0x0000, 0x9000, 0x9001}, /* internal BIOS use */
+	{0x0000, 0xA000, 0xBFFF}, /* write only */
+	{0x0000, 0xEFF0, 0xEFFF}, /* internal BIOS use */
+	/* handled by kernel: dell-laptop */
+	{0x0000, BRIGHTNESS_TOKEN,	BRIGHTNESS_TOKEN},
+	{0x0000, KBD_LED_OFF_TOKEN,	KBD_LED_AUTO_TOKEN},
+	{0x0000, KBD_LED_AC_TOKEN,	KBD_LED_AC_TOKEN},
+	{0x0000, KBD_LED_AUTO_25_TOKEN,	KBD_LED_AUTO_75_TOKEN},
+	{0x0000, KBD_LED_AUTO_100_TOKEN,	KBD_LED_AUTO_100_TOKEN},
+	{0x0000, GLOBAL_MIC_MUTE_ENABLE,	GLOBAL_MIC_MUTE_DISABLE},
+};
+
+static LIST_HEAD(smbios_device_list);
 
 int dell_smbios_error(int value)
 {
@@ -55,42 +141,175 @@ int dell_smbios_error(int value)
 }
 EXPORT_SYMBOL_GPL(dell_smbios_error);
 
-struct calling_interface_buffer *dell_smbios_get_buffer(void)
+int dell_smbios_register_device(struct device *d, void *call_fn)
 {
-	mutex_lock(&buffer_mutex);
-	dell_smbios_clear_buffer();
-	return buffer;
+	struct smbios_device *priv;
+
+	priv = devm_kzalloc(d, sizeof(struct smbios_device), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	get_device(d);
+	priv->device = d;
+	priv->call_fn = call_fn;
+	mutex_lock(&smbios_mutex);
+	list_add_tail(&priv->list, &smbios_device_list);
+	mutex_unlock(&smbios_mutex);
+	dev_dbg(d, "Added device: %s\n", d->driver->name);
+	return 0;
 }
-EXPORT_SYMBOL_GPL(dell_smbios_get_buffer);
+EXPORT_SYMBOL_GPL(dell_smbios_register_device);
 
-void dell_smbios_clear_buffer(void)
+void dell_smbios_unregister_device(struct device *d)
 {
-	memset(buffer, 0, sizeof(struct calling_interface_buffer));
+	struct smbios_device *priv;
+
+	mutex_lock(&smbios_mutex);
+	list_for_each_entry(priv, &smbios_device_list, list) {
+		if (priv->device == d) {
+			list_del(&priv->list);
+			put_device(d);
+			break;
+		}
+	}
+	mutex_unlock(&smbios_mutex);
+	dev_dbg(d, "Remove device: %s\n", d->driver->name);
 }
-EXPORT_SYMBOL_GPL(dell_smbios_clear_buffer);
+EXPORT_SYMBOL_GPL(dell_smbios_unregister_device);
 
-void dell_smbios_release_buffer(void)
+int dell_smbios_call_filter(struct device *d,
+			    struct calling_interface_buffer *buffer)
 {
-	mutex_unlock(&buffer_mutex);
+	u16 t = 0;
+	int i;
+
+	/* can't make calls over 30 */
+	if (buffer->cmd_class > 30) {
+		dev_dbg(d, "class too big: %u\n", buffer->cmd_class);
+		return -EINVAL;
+	}
+
+	/* supported calls on the particular system */
+	if (!(da_supported_commands & (1 << buffer->cmd_class))) {
+		dev_dbg(d, "invalid command, supported commands: 0x%8x\n",
+			da_supported_commands);
+		return -EINVAL;
+	}
+
+	/* match against call blacklist  */
+	for (i = 0; i < ARRAY_SIZE(call_blacklist); i++) {
+		if (buffer->cmd_class != call_blacklist[i].cmd_class)
+			continue;
+		if (buffer->cmd_select != call_blacklist[i].cmd_select &&
+		    call_blacklist[i].cmd_select != -1)
+			continue;
+		dev_dbg(d, "blacklisted command: %u/%u\n",
+			buffer->cmd_class, buffer->cmd_select);
+		return -EINVAL;
+	}
+
+	/* if a token call, find token ID */
+
+	if ((buffer->cmd_class == CLASS_TOKEN_READ ||
+	     buffer->cmd_class == CLASS_TOKEN_WRITE) &&
+	     buffer->cmd_select < 3) {
+		/* find the matching token ID */
+		for (i = 0; i < da_num_tokens; i++) {
+			if (da_tokens[i].location != buffer->input[0])
+				continue;
+			t = da_tokens[i].tokenID;
+			break;
+		}
+
+		/* token call; but token didn't exist */
+		if (!t) {
+			dev_dbg(d, "token at location %04x doesn't exist\n",
+				buffer->input[0]);
+			return -EINVAL;
+		}
+
+		/* match against token blacklist */
+		for (i = 0; i < ARRAY_SIZE(token_blacklist); i++) {
+			if (!token_blacklist[i].min || !token_blacklist[i].max)
+				continue;
+			if (t >= token_blacklist[i].min &&
+			    t <= token_blacklist[i].max)
+				return -EINVAL;
+		}
+
+		/* match against token whitelist */
+		for (i = 0; i < ARRAY_SIZE(token_whitelist); i++) {
+			if (!token_whitelist[i].min || !token_whitelist[i].max)
+				continue;
+			if (t < token_whitelist[i].min ||
+			    t > token_whitelist[i].max)
+				continue;
+			if (!token_whitelist[i].need_capability ||
+			    capable(token_whitelist[i].need_capability)) {
+				dev_dbg(d, "whitelisted token: %x\n", t);
+				return 0;
+			}
+
+		}
+	}
+	/* match against call whitelist */
+	for (i = 0; i < ARRAY_SIZE(call_whitelist); i++) {
+		if (buffer->cmd_class != call_whitelist[i].cmd_class)
+			continue;
+		if (buffer->cmd_select != call_whitelist[i].cmd_select)
+			continue;
+		if (!call_whitelist[i].need_capability ||
+		    capable(call_whitelist[i].need_capability)) {
+			dev_dbg(d, "whitelisted capable command: %u/%u\n",
+			buffer->cmd_class, buffer->cmd_select);
+			return 0;
+		}
+		dev_dbg(d, "missing capability %d for %u/%u\n",
+			call_whitelist[i].need_capability,
+			buffer->cmd_class, buffer->cmd_select);
+
+	}
+
+	/* not in a whitelist, only allow processes with capabilities */
+	if (capable(CAP_SYS_RAWIO)) {
+		dev_dbg(d, "Allowing %u/%u due to CAP_SYS_RAWIO\n",
+			buffer->cmd_class, buffer->cmd_select);
+		return 0;
+	}
+
+	return -EACCES;
 }
-EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);
+EXPORT_SYMBOL_GPL(dell_smbios_call_filter);
 
-void dell_smbios_send_request(int class, int select)
+int dell_smbios_call(struct calling_interface_buffer *buffer)
 {
-	struct smi_cmd command;
+	int (*call_fn)(struct calling_interface_buffer *) = NULL;
+	struct device *selected_dev = NULL;
+	struct smbios_device *priv;
+	int ret;
 
-	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;
+	mutex_lock(&smbios_mutex);
+	list_for_each_entry(priv, &smbios_device_list, list) {
+		if (!selected_dev || priv->device->id >= selected_dev->id) {
+			dev_dbg(priv->device, "Trying device ID: %d\n",
+				priv->device->id);
+			call_fn = priv->call_fn;
+			selected_dev = priv->device;
+		}
+	}
+
+	if (!selected_dev) {
+		ret = -ENODEV;
+		pr_err("No dell-smbios drivers are loaded\n");
+		goto out_smbios_call;
+	}
 
-	buffer->class = class;
-	buffer->select = select;
+	ret = call_fn(buffer);
 
-	dcdbas_smi_request(&command);
+out_smbios_call:
+	mutex_unlock(&smbios_mutex);
+	return ret;
 }
-EXPORT_SYMBOL_GPL(dell_smbios_send_request);
+EXPORT_SYMBOL_GPL(dell_smbios_call);
 
 struct calling_interface_token *dell_smbios_find_token(int tokenid)
 {
@@ -139,8 +358,7 @@ static void __init parse_da_table(const struct dmi_header *dm)
 	if (dm->length < 17)
 		return;
 
-	da_command_address = table->cmdIOAddress;
-	da_command_code = table->cmdIOCode;
+	da_supported_commands = table->supportedCmds;
 
 	new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
 				 sizeof(struct calling_interface_token),
@@ -156,6 +374,27 @@ static void __init parse_da_table(const struct dmi_header *dm)
 	da_num_tokens += tokens;
 }
 
+static void zero_duplicates(struct device *dev)
+{
+	int i, j;
+
+	for (i = 0; i < da_num_tokens; i++) {
+		if (da_tokens[i].tokenID == 0)
+			continue;
+		for (j = i+1; j < da_num_tokens; j++) {
+			if (da_tokens[j].tokenID == 0)
+				continue;
+			if (da_tokens[i].tokenID == da_tokens[j].tokenID) {
+				dev_dbg(dev, "Zeroing dup token ID %x(%x/%x)\n",
+					da_tokens[j].tokenID,
+					da_tokens[j].location,
+					da_tokens[j].value);
+				da_tokens[j].tokenID = 0;
+			}
+		}
+	}
+}
+
 static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 {
 	switch (dm->type) {
@@ -169,10 +408,160 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 	}
 }
 
+static int match_attribute(struct device *dev,
+			   struct device_attribute *attr)
+{
+	int i;
+
+	for (i = 0; i < da_num_tokens * 2; i++) {
+		if (!token_attrs[i])
+			continue;
+		if (strcmp(token_attrs[i]->name, attr->attr.name) == 0)
+			return i/2;
+	}
+	dev_dbg(dev, "couldn't match: %s\n", attr->attr.name);
+	return -EINVAL;
+}
+
+static ssize_t location_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	int i;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	i = match_attribute(dev, attr);
+	if (i > 0)
+		return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].location);
+	return 0;
+}
+
+static ssize_t value_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	int i;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	i = match_attribute(dev, attr);
+	if (i > 0)
+		return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].value);
+	return 0;
+}
+
+static struct attribute_group smbios_attribute_group = {
+	.name = "tokens"
+};
+
+static struct platform_driver platform_driver = {
+	.driver = {
+		.name = "dell-smbios",
+	},
+};
+
+static int build_tokens_sysfs(struct platform_device *dev)
+{
+	char *location_name;
+	char *value_name;
+	size_t size;
+	int ret;
+	int i, j;
+
+	/* (number of tokens  + 1 for null terminated */
+	size = sizeof(struct device_attribute) * (da_num_tokens + 1);
+	token_location_attrs = kzalloc(size, GFP_KERNEL);
+	if (!token_location_attrs)
+		return -ENOMEM;
+	token_value_attrs = kzalloc(size, GFP_KERNEL);
+	if (!token_value_attrs)
+		goto out_allocate_value;
+
+	/* need to store both location and value + terminator*/
+	size = sizeof(struct attribute *) * ((2 * da_num_tokens) + 1);
+	token_attrs = kzalloc(size, GFP_KERNEL);
+	if (!token_attrs)
+		goto out_allocate_attrs;
+
+	for (i = 0, j = 0; i < da_num_tokens; i++) {
+		/* skip empty */
+		if (da_tokens[i].tokenID == 0)
+			continue;
+		/* add location */
+		location_name = kasprintf(GFP_KERNEL, "%04x_location",
+					  da_tokens[i].tokenID);
+		if (location_name == NULL)
+			goto out_unwind_strings;
+		sysfs_attr_init(&token_location_attrs[i].attr);
+		token_location_attrs[i].attr.name = location_name;
+		token_location_attrs[i].attr.mode = 0444;
+		token_location_attrs[i].show = location_show;
+		token_attrs[j++] = &token_location_attrs[i].attr;
+
+		/* add value */
+		value_name = kasprintf(GFP_KERNEL, "%04x_value",
+				       da_tokens[i].tokenID);
+		if (value_name == NULL)
+			goto loop_fail_create_value;
+		sysfs_attr_init(&token_value_attrs[i].attr);
+		token_value_attrs[i].attr.name = value_name;
+		token_value_attrs[i].attr.mode = 0444;
+		token_value_attrs[i].show = value_show;
+		token_attrs[j++] = &token_value_attrs[i].attr;
+		continue;
+
+loop_fail_create_value:
+		kfree(value_name);
+		goto out_unwind_strings;
+	}
+	smbios_attribute_group.attrs = token_attrs;
+
+	ret = sysfs_create_group(&dev->dev.kobj, &smbios_attribute_group);
+	if (ret)
+		goto out_unwind_strings;
+	return 0;
+
+out_unwind_strings:
+	for (i = i-1; i > 0; i--) {
+		kfree(token_location_attrs[i].attr.name);
+		kfree(token_value_attrs[i].attr.name);
+	}
+	kfree(token_attrs);
+out_allocate_attrs:
+	kfree(token_value_attrs);
+out_allocate_value:
+	kfree(token_location_attrs);
+
+	return -ENOMEM;
+}
+
+static void free_group(struct platform_device *pdev)
+{
+	int i;
+
+	sysfs_remove_group(&pdev->dev.kobj,
+				&smbios_attribute_group);
+	for (i = 0; i < da_num_tokens; i++) {
+		kfree(token_location_attrs[i].attr.name);
+		kfree(token_value_attrs[i].attr.name);
+	}
+	kfree(token_attrs);
+	kfree(token_value_attrs);
+	kfree(token_location_attrs);
+}
+
 static int __init dell_smbios_init(void)
 {
+	const struct dmi_device *valid;
 	int ret;
 
+	valid = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL);
+	if (!valid) {
+		pr_err("Unable to run on non-Dell system\n");
+		return -ENODEV;
+	}
+
 	dmi_walk(find_tokens, NULL);
 
 	if (!da_tokens)  {
@@ -180,27 +569,52 @@ 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);
-	if (!buffer) {
+	ret = platform_driver_register(&platform_driver);
+	if (ret)
+		goto fail_platform_driver;
+
+	platform_device = platform_device_alloc("dell-smbios", 0);
+	if (!platform_device) {
 		ret = -ENOMEM;
-		goto fail_buffer;
+		goto fail_platform_device_alloc;
 	}
+	ret = platform_device_add(platform_device);
+	if (ret)
+		goto fail_platform_device_add;
+
+	/* duplicate tokens will cause problems building sysfs files */
+	zero_duplicates(&platform_device->dev);
+
+	ret = build_tokens_sysfs(platform_device);
+	if (ret)
+		goto fail_create_group;
 
 	return 0;
 
-fail_buffer:
+fail_create_group:
+	platform_device_del(platform_device);
+
+fail_platform_device_add:
+	platform_device_put(platform_device);
+
+fail_platform_device_alloc:
+	platform_driver_unregister(&platform_driver);
+
+fail_platform_driver:
 	kfree(da_tokens);
 	return ret;
 }
 
 static void __exit dell_smbios_exit(void)
 {
+	mutex_lock(&smbios_mutex);
+	if (platform_device) {
+		free_group(platform_device);
+		platform_device_unregister(platform_device);
+		platform_driver_unregister(&platform_driver);
+	}
 	kfree(da_tokens);
-	free_page((unsigned long)buffer);
+	mutex_unlock(&smbios_mutex);
 }
 
 subsys_initcall(dell_smbios_init);