diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 99fecd2..6ce165d 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -65,7 +65,7 @@
 #include <linux/string.h>
 #include <linux/ctype.h>
 #include <linux/pnp.h>
-
+#include <linux/ipmi.h>
 #ifdef CONFIG_PPC_OF
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
@@ -1808,6 +1808,471 @@ static __devinit void hardcode_find_bmc(void)
 
 #include <linux/acpi.h>
 
+#define IPMI_FLAGS_HANDLER_INSTALL	0
+#define ACPI_IPMI_OK			0
+#define ACPI_IPMI_TIMEOUT		0x10
+#define ACPI_IPMI_UNKNOWN		0x07
+/* the IPMI timeout is 30s */
+#define IPMI_TIMEOUT			(30 * HZ)
+
+struct acpi_ipmi_device {
+	acpi_handle handle;
+	struct acpi_device *device;
+	/* the device list attached to driver_data.ipmi_devices */
+	struct list_head head;
+	ipmi_user_t 	user_interface;
+	struct mutex	mutex_lock;
+	/* the IPMI request message list */
+	struct list_head tx_msg_list;
+	long curr_msgid;
+	/* IPMI flags */
+	unsigned long flags;
+	/* IPMI interface number */
+	int ipmi_ifnum;
+	struct smi_info *smi_info;
+};
+
+struct ipmi_driver_data {
+	int device_count;
+	struct list_head	ipmi_devices;
+	struct ipmi_smi_watcher	bmc_events;
+	struct ipmi_user_hndl	ipmi_hndlrs;
+};
+
+struct acpi_ipmi_msg {
+	/* message list */
+	struct list_head head;
+	/*
+	 * General speaking the addr type should be SI_ADDR_TYPE. And
+	 * the addr channel should be BMC.
+	 * In fact it can also be IPMB type. But we will have to
+	 * parse it from the Netfn command buffer. It is so complex
+	 * that it is skipped.
+	 */
+	struct ipmi_addr addr;
+	/* tx message id */
+	long tx_msgid;
+	/* it is used to track whether the IPMI message is finished */
+	struct completion tx_complete;
+	struct kernel_ipmi_msg tx_message;
+	int	msg_done;
+	/* tx data . And copy it from ACPI object buffer */
+	u8	tx_data[64];
+	int	tx_len;
+	/* get the response data */
+	u8	rx_data[64];
+	/* the response length. The netfn & cmd is excluded. */
+	int	rx_len;
+	struct acpi_ipmi_device *device;
+};
+
+/*
+ * IPMI request/response buffer.
+ * The length is 66 bytes.
+ */
+struct acpi_ipmi_buffer {
+	/* status code of a given IPMI command */
+	u8 status_code;
+	/* the length of the payload */
+	u8 length;
+	/*
+	 * the payload. Before the operation is carried out, it represents the
+	 * request message payload. After the operation is carried out, it
+	 * stores the response message returned by IPMI command.
+	 */
+	u8 data[64];
+};
+
+
+static void ipmi_register_bmc(int iface, struct device *dev);
+static void ipmi_bmc_gone(int iface);
+static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
+
+static struct ipmi_driver_data driver_data = {
+	.ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
+	.bmc_events = {
+		.owner = THIS_MODULE,
+		.new_smi = ipmi_register_bmc,
+		.smi_gone = ipmi_bmc_gone,
+	},
+	.ipmi_hndlrs = {
+		.ipmi_recv_hndl = ipmi_msg_handler,
+	},
+};
+
+static
+struct acpi_ipmi_msg *acpi_alloc_ipmi_msg(struct acpi_ipmi_device *ipmi)
+{
+	struct acpi_ipmi_msg *ipmi_msg;
+
+	ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
+	if (!ipmi_msg)	{
+		printk(KERN_DEBUG "Can't allocate memory for ipmi_msg\n");
+		return NULL;
+	}
+	init_completion(&ipmi_msg->tx_complete);
+	INIT_LIST_HEAD(&ipmi_msg->head);
+	ipmi_msg->device = ipmi;
+	return ipmi_msg;
+}
+
+static void acpi_format_ipmi_msg(struct acpi_ipmi_msg *tx_msg,
+		acpi_physical_address address,
+		acpi_integer *value)
+{
+	struct kernel_ipmi_msg *msg;
+	u8	temp_value;
+	struct acpi_ipmi_buffer *buffer;
+	struct acpi_ipmi_device *device;
+
+	msg = &tx_msg->tx_message;
+	/* get the netfn */
+	temp_value = (address >> 8) & 0xff;
+	msg->netfn = temp_value;
+	/* get the command */
+	temp_value = address & 0xff;
+	msg->cmd = temp_value;
+	msg->data = tx_msg->tx_data;
+	/*
+	 * value is the parameter passed by the IPMI opregion space handler.
+	 * It points to the IPMI request message buffer
+	 */
+	buffer = (struct acpi_ipmi_buffer *)value;
+	/* copy the tx message data */
+	msg->data_len = buffer->length;
+	memcpy(tx_msg->tx_data, buffer->data, msg->data_len);
+	/*
+	 * now the default type is SYSTEM_INTERFACE and channel type is BMC.
+	 * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE,
+	 * the addr type should be changed to IPMB.
+	 */
+	tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	tx_msg->addr.channel = IPMI_BMC_CHANNEL;
+	tx_msg->addr.data[0] = 0;
+
+	/*
+	 * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE, we should
+	 * parse the IPMI request message buffer to get the IPMB address.
+	 * If so, please fix me.
+	 */
+
+	/* Get the msgid */
+	device = tx_msg->device;
+	mutex_lock(&device->mutex_lock);
+	device->curr_msgid++;
+	tx_msg->tx_msgid = device->curr_msgid;
+	mutex_unlock(&device->mutex_lock);
+}
+
+static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
+		acpi_integer *value, int timeout)
+{
+	struct acpi_ipmi_buffer *buffer;
+
+	/*
+	 * value is also used as output parameter. It represents the response
+	 * IPMI message returned by IPMI command.
+	 */
+	buffer = (struct acpi_ipmi_buffer *)value;
+	/* when timeout is zero, it means that the timeout happens */
+	if (!timeout) {
+		/* the status code is ACPI_IPMI_TIMEOUT */
+		buffer->status_code = ACPI_IPMI_TIMEOUT;
+		return;
+	}
+	/*
+	 * If the flag of msg_done is not set, it means that the IPMI command
+	 * is not executed correctly.
+	 * The status code will be ACPI_IPMI_UNKNOWN.
+	 */
+	if (!msg->msg_done) {
+		buffer->status_code = ACPI_IPMI_UNKNOWN;
+		return;
+	}
+	/*
+	 * If the IPMI response message is obtained correctly, the status code
+	 * will be ACPI_IPMI_OK
+	 */
+	buffer->status_code = ACPI_IPMI_OK;
+	buffer->length = msg->rx_len;
+	memcpy(buffer->data, msg->rx_data, msg->rx_len);
+}
+
+static void ipmi_destroy_tx_msg(struct acpi_ipmi_device *ipmi)
+{
+	struct acpi_ipmi_msg *tx_msg = NULL, *temp;
+	int count = 20;
+
+	list_for_each_entry_safe(tx_msg, temp, &ipmi->tx_msg_list, head) {
+		/* wake up the sleep thread on the Tx msg */
+		complete(&tx_msg->tx_complete);
+	}
+	/* wait for about 20 ticks to flush the tx message list */
+	while (count--) {
+		if (list_empty(&ipmi->tx_msg_list))
+			break;
+		schedule_timeout(1);
+	}
+	if (!list_empty(&ipmi->tx_msg_list))
+		printk(KERN_DEBUG "tx msg list is not NULL\n");
+
+}
+
+static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
+{
+	struct acpi_ipmi_device *ipmi_device = user_msg_data;
+	int msg_found = 0;
+	struct acpi_ipmi_msg *tx_msg;
+
+	if (msg->user != ipmi_device->user_interface) {
+		printk(KERN_DEBUG "Incorrect IPMI user\n");
+		ipmi_free_recv_msg(msg);
+		return;
+	}
+	mutex_lock(&ipmi_device->mutex_lock);
+	list_for_each_entry(tx_msg, &ipmi_device->tx_msg_list, head) {
+		if (msg->msgid == tx_msg->tx_msgid) {
+			/* find the message id */
+			msg_found = 1;
+			break;
+		}
+	}
+
+	mutex_unlock(&ipmi_device->mutex_lock);
+	if (!msg_found) {
+		/* no matched msg is found . But we should free it */
+		ipmi_free_recv_msg(msg);
+		printk(KERN_DEBUG "Incorrect MSG is found \n");
+		return;
+	}
+
+	if (msg->msg.data_len > 1) {
+		/* copy the response data to Rx_data buffer */
+		memcpy(tx_msg->rx_data, msg->msg_data, msg->msg.data_len);
+		tx_msg->rx_len = msg->msg.data_len;
+		tx_msg->msg_done = 1;
+	}
+	complete(&tx_msg->tx_complete);
+	ipmi_free_recv_msg(msg);
+};
+
+static void ipmi_register_bmc(int iface, struct device *dev)
+{
+	struct acpi_ipmi_device *ipmi_device, *temp;
+	struct acpi_device *device;
+	ipmi_user_t		user;
+	int err;
+
+	if (list_empty(&driver_data.ipmi_devices))
+		return;
+
+	list_for_each_entry_safe(ipmi_device, temp,
+					&driver_data.ipmi_devices, head) {
+		device = ipmi_device->device;
+		if (ipmi_device->user_interface) {
+			/*
+			 * Only one user interface is allowed to be registered
+			 * for one IPMI device.
+			 * If we already create the user interface for
+			 * one IPMI device, skip it
+			 */
+			continue;
+		}
+		if (dev == &device->dev) {
+			/*
+			 * If the dev is identical to the ACPI device,
+			 * create the user interface.
+			 */
+			err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
+						ipmi_device, &user);
+			if (err == 0) {
+				ipmi_device->user_interface = user;
+				ipmi_device->ipmi_ifnum = iface;
+			}
+		}
+	}
+}
+
+static void ipmi_bmc_gone(int iface)
+{
+	struct acpi_ipmi_device *ipmi_device, *temp;
+
+	if (list_empty(&driver_data.ipmi_devices))
+		return;
+
+	list_for_each_entry_safe(ipmi_device, temp,
+				&driver_data.ipmi_devices, head) {
+		if (ipmi_device->user_interface &&
+				(ipmi_device->ipmi_ifnum == iface)) {
+			ipmi_destroy_user(ipmi_device->user_interface);
+			ipmi_device->user_interface = NULL;
+			ipmi_destroy_tx_msg(ipmi_device);
+		}
+	}
+}
+/* --------------------------------------------------------------------------
+ * 			Address Space Management
+   -------------------------------------------------------------------------- */
+/*
+ * This is the IPMI opregion space handler.
+ * @function: indicates the read/write. In fact as the IPMI message is driven
+ * by command, only write is meaningful.
+ * @address: This contains the netfn/command of IPMI request message.
+ * @bits   : not used.
+ * @value  : it is an in/out parameter. It points to the IPMI message buffer.
+ *	     Before the IPMI message is sent, it represents the actual request
+ *	     IPMI message. After the IPMI message is finished, it represents
+ *	     the response IPMI message returned by IPMI command.
+ * @handler_context: IPMI device context.
+ */
+
+static acpi_status
+acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
+		      u32 bits, acpi_integer *value,
+		      void *handler_context, void *region_context)
+{
+	struct acpi_ipmi_msg *tx_msg = NULL;
+	struct acpi_ipmi_device *ipmi_device =
+			(struct acpi_ipmi_device *) handler_context;
+	int err;
+	acpi_status status;
+	/*
+	 * IPMI opregion message.
+	 * IPMI message is firstly written to the BMC and system software
+	 * can get the respsonse. So it is unmeaningful for the IPMI read
+	 * access.
+	 */
+	if ((function & ACPI_IO_MASK) == ACPI_READ) {
+		/* Read function is not supported. AE_TYPE is returned. */
+		return AE_TYPE;
+	}
+	if (!ipmi_device->user_interface)
+		return AE_NOT_EXIST;
+
+	tx_msg = acpi_alloc_ipmi_msg(ipmi_device);
+	if (!tx_msg)
+		return AE_NO_MEMORY;
+
+	acpi_format_ipmi_msg(tx_msg, address, value);
+	mutex_lock(&ipmi_device->mutex_lock);
+	list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
+	mutex_unlock(&ipmi_device->mutex_lock);
+	err = ipmi_request_settime(ipmi_device->user_interface,
+					&tx_msg->addr,
+					tx_msg->tx_msgid,
+					&tx_msg->tx_message,
+					NULL, 0, 0, 0);
+	if (err) {
+		status = AE_ERROR;
+		goto end_label;
+	}
+	err = wait_for_completion_timeout(&tx_msg->tx_complete, IPMI_TIMEOUT);
+
+	acpi_format_ipmi_response(tx_msg, value, err);
+	status = AE_OK;
+
+end_label:
+	mutex_lock(&ipmi_device->mutex_lock);
+	list_del(&tx_msg->head);
+	mutex_unlock(&ipmi_device->mutex_lock);
+	kfree(tx_msg);
+	return status;
+}
+
+static void ipmi_remove_handler(struct acpi_ipmi_device *ipmi)
+{
+	if (!test_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags))
+		return;
+
+	acpi_remove_address_space_handler(ipmi->handle,
+				ACPI_ADR_SPACE_IPMI, &acpi_ipmi_space_handler);
+
+	clear_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags);
+}
+
+static int ipmi_install_handler(struct acpi_ipmi_device *ipmi)
+{
+	acpi_status status;
+
+	if (test_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags))
+		return 0;
+
+	status = acpi_install_address_space_handler(ipmi->handle,
+						    ACPI_ADR_SPACE_IPMI,
+						    &acpi_ipmi_space_handler,
+						    NULL, ipmi);
+	if (ACPI_FAILURE(status)) {
+		printk(KERN_DEBUG "Can't register IPMI opregion %s\n",
+					acpi_device_bid(ipmi->device));
+		return -EINVAL;
+	}
+
+	test_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags);
+
+	return 0;
+}
+
+static void acpi_register_ipmi_handler(struct acpi_ipmi_device *ipmi_device)
+{
+
+	mutex_init(&ipmi_device->mutex_lock);
+	INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
+
+	if (ipmi_install_handler(ipmi_device)) {
+		/*
+		 * can't register the IPMI opregion. We will print
+		 * some debug info and continue to register ipmi
+		 * opregion for next device.
+		 */
+		printk(KERN_DEBUG "Can't register IPMI opregion %s\n",
+				acpi_device_bid(ipmi_device->device));
+	}
+	list_add(&ipmi_device->head, &driver_data.ipmi_devices);
+}
+
+static void acpi_remove_ipmi_handler(struct acpi_ipmi_device *ipmi_device)
+{
+	if (!ipmi_device)
+		return;
+
+	if (ipmi_device->user_interface) {
+		/*
+		 * If the IPMI user interface is created, it
+		 * should be destroyed.
+		 */
+		ipmi_destroy_user(ipmi_device->user_interface);
+		ipmi_device->user_interface = NULL;
+	}
+	list_del(&ipmi_device->head);
+
+	if (!list_empty(&ipmi_device->tx_msg_list))
+		ipmi_destroy_tx_msg(ipmi_device);
+
+	ipmi_remove_handler(ipmi_device);
+	kfree(ipmi_device);
+}
+
+static int acpi_ipmi_opregion_init(void)
+{
+	int result = 0;
+
+	if (acpi_disabled)
+		return result;
+
+	result = ipmi_smi_watcher_register(&driver_data.bmc_events);
+
+	return result;
+}
+
+static void acpi_ipmi_opregion_exit(void)
+{
+	if (acpi_disabled)
+		return;
+
+	ipmi_smi_watcher_unregister(&driver_data.bmc_events);
+
+}
+
 /*
  * Once we get an ACPI failure, we don't try any more, because we go
  * through the tables sequentially.  Once we don't find a table, there
@@ -2033,6 +2498,8 @@ static int __devinit ipmi_pnp_probe(struct pnp_dev *dev,
 	acpi_handle handle;
 	acpi_status status;
 	unsigned long long tmp;
+	int ret;
+	struct acpi_ipmi_device *p_ipmi;
 
 	acpi_dev = pnp_acpi_device(dev);
 	if (!acpi_dev)
@@ -2042,6 +2509,13 @@ static int __devinit ipmi_pnp_probe(struct pnp_dev *dev,
 	if (!info)
 		return -ENOMEM;
 
+	p_ipmi = kzalloc(sizeof(*p_ipmi), GFP_KERNEL);
+	if (!p_ipmi) {
+		printk(KERN_ERR "Can't allocate memory for IPMI device\n");
+		kfree(info);
+		return -ENOMEM;
+	}
+
 	info->addr_source = "ACPI";
 
 	handle = acpi_dev->handle;
@@ -2094,20 +2568,36 @@ static int __devinit ipmi_pnp_probe(struct pnp_dev *dev,
 	}
 
 	info->dev = &acpi_dev->dev;
-	pnp_set_drvdata(dev, info);
+	p_ipmi->smi_info = info;
+	pnp_set_drvdata(dev, p_ipmi);
 
-	return try_smi_init(info);
+	p_ipmi->device = acpi_dev;
+	p_ipmi->handle = handle;
+	p_ipmi->ipmi_ifnum = -1;
 
+	ret = try_smi_init(info);
+	if (!ret) {
+		acpi_register_ipmi_handler(p_ipmi);
+		return ret;
+	}
 err_free:
+	pnp_set_drvdata(dev, NULL);
+	kfree(p_ipmi);
 	kfree(info);
 	return -EINVAL;
 }
 
 static void __devexit ipmi_pnp_remove(struct pnp_dev *dev)
 {
-	struct smi_info *info = pnp_get_drvdata(dev);
+	struct acpi_ipmi_device *p_ipmi;
+	struct smi_info *info;
+
+	p_ipmi = pnp_get_drvdata(dev);
+	info = p_ipmi->smi_info;
 
+	acpi_remove_ipmi_handler(p_ipmi);
 	cleanup_one_si(info);
+	pnp_set_drvdata(dev, NULL);
 }
 
 static const struct pnp_device_id pnp_dev_table[] = {
@@ -3207,6 +3697,7 @@ static __devinit int init_ipmi_si(void)
 
 #ifdef CONFIG_ACPI
 	spmi_find_bmc();
+	acpi_ipmi_opregion_init();
 #endif
 
 #ifdef CONFIG_PCI
@@ -3327,10 +3818,14 @@ static __exit void cleanup_ipmi_si(void)
 
 	if (!initialized)
 		return;
+#ifdef CONFIG_ACPI
+	acpi_ipmi_opregion_exit();
+#endif
 
 #ifdef CONFIG_PCI
 	pci_unregister_driver(&ipmi_pci_driver);
 #endif
+
 #ifdef CONFIG_PNP
 	pnp_unregister_driver(&ipmi_pnp_driver);
 #endif
