8 files changed, 653 insertions, 4 deletions

diff --git a/Documentation/IPMI.txt b/Documentation/IPMI.txt
index 69dd29ed824e..b2bea15137d2 100644
--- a/Documentation/IPMI.txt
+++ b/Documentation/IPMI.txt
@@ -533,6 +533,33 @@ completion during sending a panic event.
 Other Pieces
 ------------
 
+Get the detailed info related with the IPMI device
+--------------------------------------------------
+
+Some users need more detailed information about a device, like where
+the address came from or the raw base device for the IPMI interface.
+You can use the IPMI smi_watcher to catch the IPMI interfaces as they
+come or go, and to grab the information, you can use the function
+ipmi_get_smi_info(), which returns the following structure:
+
+struct ipmi_smi_info {
+        enum ipmi_addr_src addr_src;
+        struct device *dev;
+        union {
+                struct {
+                        void *acpi_handle;
+                } acpi_info;
+        } addr_info;
+};
+
+Currently special info for only for SI_ACPI address sources is
+returned.  Others may be added as necessary.
+
+Note that the dev pointer is included in the above structure, and
+assuming ipmi_smi_get_info returns success, you must call put_device
+on the dev pointer.
+
+
 Watchdog
 --------
 
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 788e88eb18ec..865fcb3c4807 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -207,6 +207,17 @@ config ACPI_PROCESSOR
 
           To compile this driver as a module, choose M here:
           the module will be called processor.
+config ACPI_IPMI
+        tristate "IPMI"
+        depends on EXPERIMENTAL && IPMI_SI && IPMI_HANDLER
+        default n
+        help
+          This driver enables the ACPI to access the BMC controller. And it
+          uses the IPMI request/response message to communicate with BMC
+          controller, which can be found on on the server.
+
+          To compile this driver as a module, choose M here:
+          the module will be called as acpi_ipmi.
 
 config ACPI_HOTPLUG_CPU
         bool
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 9cc9f2c4da79..d113fa5100b2 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -69,5 +69,6 @@ processor-y			+= processor_idle.o processor_thermal.o
 processor-$(CONFIG_CPU_FREQ)    += processor_perflib.o
 
 obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o
+obj-$(CONFIG_ACPI_IPMI)         += acpi_ipmi.o
 
 obj-$(CONFIG_ACPI_APEI)         += apei/
diff --git a/drivers/acpi/acpi_ipmi.c b/drivers/acpi/acpi_ipmi.c
new file mode 100644
index 000000000000..f40acef80269
--- /dev/null
+++ b/drivers/acpi/acpi_ipmi.c
@@ -0,0 +1,525 @@
+/*
+ *  acpi_ipmi.c - ACPI IPMI opregion
+ *
+ *  Copyright (C) 2010 Intel Corporation
+ *  Copyright (C) 2010 Zhao Yakui <yakui.zhao@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or (at
+ *  your option) any later version.
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <linux/ipmi.h>
+#include <linux/device.h>
+#include <linux/pnp.h>
+
+MODULE_AUTHOR("Zhao Yakui");
+MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
+MODULE_LICENSE("GPL");
+
+#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 5s */
+#define IPMI_TIMEOUT                    (5 * HZ)
+
+struct acpi_ipmi_device {
+        /* the device list attached to driver_data.ipmi_devices */
+        struct list_head head;
+        /* the IPMI request message list */
+        struct list_head tx_msg_list;
+        struct mutex    tx_msg_lock;
+        acpi_handle handle;
+        struct pnp_dev *pnp_dev;
+        ipmi_user_t     user_interface;
+        int ipmi_ifnum; /* IPMI interface number */
+        long curr_msgid;
+        unsigned long flags;
+        struct ipmi_smi_info smi_data;
+};
+
+struct ipmi_driver_data {
+        struct list_head        ipmi_devices;
+        struct ipmi_smi_watcher bmc_events;
+        struct ipmi_user_hndl   ipmi_hndlrs;
+        struct mutex            ipmi_lock;
+};
+
+struct acpi_ipmi_msg {
+        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;
+        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;
+        u8      rx_data[64];
+        int     rx_len;
+        struct acpi_ipmi_device *device;
+};
+
+/* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
+struct acpi_ipmi_buffer {
+        u8 status;
+        u8 length;
+        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 void acpi_add_ipmi_device(struct acpi_ipmi_device *ipmi_device);
+static void acpi_remove_ipmi_device(struct acpi_ipmi_device *ipmi_device);
+
+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;
+        struct pnp_dev *pnp_dev = ipmi->pnp_dev;
+
+        ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
+        if (!ipmi_msg)  {
+                dev_warn(&pnp_dev->dev, "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;
+}
+
+#define         IPMI_OP_RGN_NETFN(offset)       ((offset >> 8) & 0xff)
+#define         IPMI_OP_RGN_CMD(offset)         (offset & 0xff)
+static void acpi_format_ipmi_msg(struct acpi_ipmi_msg *tx_msg,
+                                acpi_physical_address address,
+                                acpi_integer *value)
+{
+        struct kernel_ipmi_msg *msg;
+        struct acpi_ipmi_buffer *buffer;
+        struct acpi_ipmi_device *device;
+
+        msg = &tx_msg->tx_message;
+        /*
+         * IPMI network function and command are encoded in the address
+         * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
+         */
+        msg->netfn = IPMI_OP_RGN_NETFN(address);
+        msg->cmd = IPMI_OP_RGN_CMD(address);
+        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. Then we will have to parse
+         * the IPMI request message buffer to get the IPMB address.
+         * If so, please fix me.
+         */
+        tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+        tx_msg->addr.channel = IPMI_BMC_CHANNEL;
+        tx_msg->addr.data[0] = 0;
+
+        /* Get the msgid */
+        device = tx_msg->device;
+        mutex_lock(&device->tx_msg_lock);
+        device->curr_msgid++;
+        tx_msg->tx_msgid = device->curr_msgid;
+        mutex_unlock(&device->tx_msg_lock);
+}
+
+static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
+                acpi_integer *value, int rem_time)
+{
+        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;
+        if (!rem_time && !msg->msg_done) {
+                buffer->status = ACPI_IPMI_TIMEOUT;
+                return;
+        }
+        /*
+         * If the flag of msg_done is not set or the recv length is zero, it
+         * means that the IPMI command is not executed correctly.
+         * The status code will be ACPI_IPMI_UNKNOWN.
+         */
+        if (!msg->msg_done || !msg->rx_len) {
+                buffer->status = ACPI_IPMI_UNKNOWN;
+                return;
+        }
+        /*
+         * If the IPMI response message is obtained correctly, the status code
+         * will be ACPI_IPMI_OK
+         */
+        buffer->status = ACPI_IPMI_OK;
+        buffer->length = msg->rx_len;
+        memcpy(buffer->data, msg->rx_data, msg->rx_len);
+}
+
+static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi)
+{
+        struct acpi_ipmi_msg *tx_msg, *temp;
+        int count = HZ / 10;
+        struct pnp_dev *pnp_dev = ipmi->pnp_dev;
+
+        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 100ms 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))
+                dev_warn(&pnp_dev->dev, "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;
+        struct pnp_dev *pnp_dev = ipmi_device->pnp_dev;
+
+        if (msg->user != ipmi_device->user_interface) {
+                dev_warn(&pnp_dev->dev, "Unexpected response is returned. "
+                        "returned user %p, expected user %p\n",
+                        msg->user, ipmi_device->user_interface);
+                ipmi_free_recv_msg(msg);
+                return;
+        }
+        mutex_lock(&ipmi_device->tx_msg_lock);
+        list_for_each_entry(tx_msg, &ipmi_device->tx_msg_list, head) {
+                if (msg->msgid == tx_msg->tx_msgid) {
+                        msg_found = 1;
+                        break;
+                }
+        }
+
+        mutex_unlock(&ipmi_device->tx_msg_lock);
+        if (!msg_found) {
+                dev_warn(&pnp_dev->dev, "Unexpected response (msg id %ld) is "
+                        "returned.\n", msg->msgid);
+                ipmi_free_recv_msg(msg);
+                return;
+        }
+
+        if (msg->msg.data_len) {
+                /* 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 pnp_dev *pnp_dev;
+        ipmi_user_t             user;
+        int err;
+        struct ipmi_smi_info smi_data;
+        acpi_handle handle;
+
+        err = ipmi_get_smi_info(iface, &smi_data);
+
+        if (err)
+                return;
+
+        if (smi_data.addr_src != SI_ACPI) {
+                put_device(smi_data.dev);
+                return;
+        }
+
+        handle = smi_data.addr_info.acpi_info.acpi_handle;
+
+        mutex_lock(&driver_data.ipmi_lock);
+        list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
+                /*
+                 * if the corresponding ACPI handle is already added
+                 * to the device list, don't add it again.
+                 */
+                if (temp->handle == handle)
+                        goto out;
+        }
+
+        ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
+
+        if (!ipmi_device)
+                goto out;
+
+        pnp_dev = to_pnp_dev(smi_data.dev);
+        ipmi_device->handle = handle;
+        ipmi_device->pnp_dev = pnp_dev;
+
+        err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
+                                        ipmi_device, &user);
+        if (err) {
+                dev_warn(&pnp_dev->dev, "Can't create IPMI user interface\n");
+                kfree(ipmi_device);
+                goto out;
+        }
+        acpi_add_ipmi_device(ipmi_device);
+        ipmi_device->user_interface = user;
+        ipmi_device->ipmi_ifnum = iface;
+        mutex_unlock(&driver_data.ipmi_lock);
+        memcpy(&ipmi_device->smi_data, &smi_data, sizeof(struct ipmi_smi_info));
+        return;
+
+out:
+        mutex_unlock(&driver_data.ipmi_lock);
+        put_device(smi_data.dev);
+        return;
+}
+
+static void ipmi_bmc_gone(int iface)
+{
+        struct acpi_ipmi_device *ipmi_device, *temp;
+
+        mutex_lock(&driver_data.ipmi_lock);
+        list_for_each_entry_safe(ipmi_device, temp,
+                                &driver_data.ipmi_devices, head) {
+                if (ipmi_device->ipmi_ifnum != iface)
+                        continue;
+
+                acpi_remove_ipmi_device(ipmi_device);
+                put_device(ipmi_device->smi_data.dev);
+                kfree(ipmi_device);
+                break;
+        }
+        mutex_unlock(&driver_data.ipmi_lock);
+}
+/* --------------------------------------------------------------------------
+ *                      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;
+        struct acpi_ipmi_device *ipmi_device = handler_context;
+        int err, rem_time;
+        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 read access
+         * of IPMI opregion.
+         */
+        if ((function & ACPI_IO_MASK) == ACPI_READ)
+                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->tx_msg_lock);
+        list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
+        mutex_unlock(&ipmi_device->tx_msg_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;
+        }
+        rem_time = wait_for_completion_timeout(&tx_msg->tx_complete,
+                                        IPMI_TIMEOUT);
+        acpi_format_ipmi_response(tx_msg, value, rem_time);
+        status = AE_OK;
+
+end_label:
+        mutex_lock(&ipmi_device->tx_msg_lock);
+        list_del(&tx_msg->head);
+        mutex_unlock(&ipmi_device->tx_msg_lock);
+        kfree(tx_msg);
+        return status;
+}
+
+static void ipmi_remove_space_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_space_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)) {
+                struct pnp_dev *pnp_dev = ipmi->pnp_dev;
+                dev_warn(&pnp_dev->dev, "Can't register IPMI opregion space "
+                        "handle\n");
+                return -EINVAL;
+        }
+        set_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags);
+        return 0;
+}
+
+static void acpi_add_ipmi_device(struct acpi_ipmi_device *ipmi_device)
+{
+
+        INIT_LIST_HEAD(&ipmi_device->head);
+
+        mutex_init(&ipmi_device->tx_msg_lock);
+        INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
+        ipmi_install_space_handler(ipmi_device);
+
+        list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
+}
+
+static void acpi_remove_ipmi_device(struct acpi_ipmi_device *ipmi_device)
+{
+        /*
+         * If the IPMI user interface is created, it should be
+         * destroyed.
+         */
+        if (ipmi_device->user_interface) {
+                ipmi_destroy_user(ipmi_device->user_interface);
+                ipmi_device->user_interface = NULL;
+        }
+        /* flush the Tx_msg list */
+        if (!list_empty(&ipmi_device->tx_msg_list))
+                ipmi_flush_tx_msg(ipmi_device);
+
+        list_del(&ipmi_device->head);
+        ipmi_remove_space_handler(ipmi_device);
+}
+
+static int __init acpi_ipmi_init(void)
+{
+        int result = 0;
+
+        if (acpi_disabled)
+                return result;
+
+        mutex_init(&driver_data.ipmi_lock);
+
+        result = ipmi_smi_watcher_register(&driver_data.bmc_events);
+
+        return result;
+}
+
+static void __exit acpi_ipmi_exit(void)
+{
+        struct acpi_ipmi_device *ipmi_device, *temp;
+
+        if (acpi_disabled)
+                return;
+
+        ipmi_smi_watcher_unregister(&driver_data.bmc_events);
+
+        /*
+         * When one smi_watcher is unregistered, it is only deleted
+         * from the smi_watcher list. But the smi_gone callback function
+         * is not called. So explicitly uninstall the ACPI IPMI oregion
+         * handler and free it.
+         */
+        mutex_lock(&driver_data.ipmi_lock);
+        list_for_each_entry_safe(ipmi_device, temp,
+                                &driver_data.ipmi_devices, head) {
+                acpi_remove_ipmi_device(ipmi_device);
+                put_device(ipmi_device->smi_data.dev);
+                kfree(ipmi_device);
+        }
+        mutex_unlock(&driver_data.ipmi_lock);
+}
+
+module_init(acpi_ipmi_init);
+module_exit(acpi_ipmi_exit);
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 2fe72f8edf44..38223e93aa98 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -970,6 +970,33 @@ out_kfree:
 }
 EXPORT_SYMBOL(ipmi_create_user);
 
+int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data)
+{
+        int           rv = 0;
+        ipmi_smi_t    intf;
+        struct ipmi_smi_handlers *handlers;
+
+        mutex_lock(&ipmi_interfaces_mutex);
+        list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
+                if (intf->intf_num == if_num)
+                        goto found;
+        }
+        /* Not found, return an error */
+        rv = -EINVAL;
+        mutex_unlock(&ipmi_interfaces_mutex);
+        return rv;
+
+found:
+        handlers = intf->handlers;
+        rv = -ENOSYS;
+        if (handlers->get_smi_info)
+                rv = handlers->get_smi_info(intf->send_info, data);
+        mutex_unlock(&ipmi_interfaces_mutex);
+
+        return rv;
+}
+EXPORT_SYMBOL(ipmi_get_smi_info);
+
 static void free_user(struct kref *ref)
 {
         ipmi_user_t user = container_of(ref, struct ipmi_user, refcount);
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index c4bacc6ec450..3a3643c6a579 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -57,6 +57,7 @@
 #include <asm/irq.h>
 #include <linux/interrupt.h>
 #include <linux/rcupdate.h>
+#include <linux/ipmi.h>
 #include <linux/ipmi_smi.h>
 #include <asm/io.h>
 #include "ipmi_si_sm.h"
@@ -107,10 +108,6 @@ enum si_type {
 };
 static char *si_to_str[] = { "kcs", "smic", "bt" };
 
-enum ipmi_addr_src {
-        SI_INVALID = 0, SI_HOTMOD, SI_HARDCODED, SI_SPMI, SI_ACPI, SI_SMBIOS,
-        SI_PCI, SI_DEVICETREE, SI_DEFAULT
-};
 static char *ipmi_addr_src_to_str[] = { NULL, "hotmod", "hardcoded", "SPMI",
                                         "ACPI", "SMBIOS", "PCI",
                                         "device-tree", "default" };
@@ -291,6 +288,7 @@ struct smi_info {
         struct task_struct *thread;
 
         struct list_head link;
+        union ipmi_smi_info_union addr_info;
 };
 
 #define smi_inc_stat(smi, stat) \
@@ -1186,6 +1184,18 @@ static int smi_start_processing(void       *send_info,
         return 0;
 }
 
+static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
+{
+        struct smi_info *smi = send_info;
+
+        data->addr_src = smi->addr_source;
+        data->dev = smi->dev;
+        data->addr_info = smi->addr_info;
+        get_device(smi->dev);
+
+        return 0;
+}
+
 static void set_maintenance_mode(void *send_info, int enable)
 {
         struct smi_info   *smi_info = send_info;
@@ -1197,6 +1207,7 @@ static void set_maintenance_mode(void *send_info, int enable)
 static struct ipmi_smi_handlers handlers = {
         .owner                  = THIS_MODULE,
         .start_processing       = smi_start_processing,
+        .get_smi_info           = get_smi_info,
         .sender                 = sender,
         .request_events         = request_events,
         .set_maintenance_mode   = set_maintenance_mode,
@@ -2157,6 +2168,7 @@ static int __devinit ipmi_pnp_probe(struct pnp_dev *dev,
         printk(KERN_INFO PFX "probing via ACPI\n");
 
         handle = acpi_dev->handle;
+        info->addr_info.acpi_info.acpi_handle = handle;
 
         /* _IFT tells us the interface type: KCS, BT, etc */
         status = acpi_evaluate_integer(handle, "_IFT", NULL, &tmp);
diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
index 65aae34759de..045f2f275cd0 100644
--- a/include/linux/ipmi.h
+++ b/include/linux/ipmi.h
@@ -454,6 +454,44 @@ unsigned int ipmi_addr_length(int addr_type);
 /* Validate that the given IPMI address is valid. */
 int ipmi_validate_addr(struct ipmi_addr *addr, int len);
 
+/*
+ * How did the IPMI driver find out about the device?
+ */
+enum ipmi_addr_src {
+        SI_INVALID = 0, SI_HOTMOD, SI_HARDCODED, SI_SPMI, SI_ACPI, SI_SMBIOS,
+        SI_PCI, SI_DEVICETREE, SI_DEFAULT
+};
+
+union ipmi_smi_info_union {
+        /*
+         * the acpi_info element is defined for the SI_ACPI
+         * address type
+         */
+        struct {
+                void *acpi_handle;
+        } acpi_info;
+};
+
+struct ipmi_smi_info {
+        enum ipmi_addr_src addr_src;
+
+        /*
+         * Base device for the interface.  Don't forget to put this when
+         * you are done.
+         */
+        struct device *dev;
+
+        /*
+         * The addr_info provides more detailed info for some IPMI
+         * devices, depending on the addr_src.  Currently only SI_ACPI
+         * info is provided.
+         */
+        union ipmi_smi_info_union addr_info;
+};
+
+/* This is to get the private info of ipmi_smi_t */
+extern int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data);
+
 #endif /* __KERNEL__ */
 
 
diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index 4b48318ac542..906590aa6907 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -39,6 +39,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
+#include <linux/ipmi.h>
 
 /* This files describes the interface for IPMI system management interface
    drivers to bind into the IPMI message handler. */
@@ -86,6 +87,13 @@ struct ipmi_smi_handlers {
         int (*start_processing)(void       *send_info,
                                 ipmi_smi_t new_intf);
 
+        /*
+         * Get the detailed private info of the low level interface and store
+         * it into the structure of ipmi_smi_data. For example: the
+         * ACPI device handle will be returned for the pnp_acpi IPMI device.
+         */
+        int (*get_smi_info)(void *send_info, struct ipmi_smi_info *data);
+
         /* Called to enqueue an SMI message to be sent.  This
            operation is not allowed to fail.  If an error occurs, it
            should report back the error in a received message.  It may