Re: [Resend PATCH] ACPI: Add the IPMI opregion driver to enable ACPI to access BMC controller

[ykzhao <yakui.zhao@intel.com>]

On Wed, 2009-12-09 at 09:58 +0800, Zhao, Yakui wrote:

Hi, Lenb
    Any comment about this patch?
    It is used to add the support of ACPI IPMI opregion so that ACPI can
also communicate with the BMC controller.

Thanks.
   Yakui
> From: Zhao Yakui <yakui.zhao@intel.com>
> 
> Add the IPMI opregion driver so that the AML code can communicate with BMC
> throught IPMI message.
>      It will create IPMI user interface for every IPMI device detected
> in ACPI namespace and install the corresponding IPMI opregion space handler.
> 
> The following describes how to process the IPMI request in IPMI space handler:
>     1. format the IPMI message based on the request in AML code.
>     IPMI system address. Now the address type is SYSTEM_INTERFACE_ADDR_TYPE
>     IPMI net function & command
>     IPMI message payload
>     2. send the IPMI message by using the function of ipmi_request_settime
>     3. wait for the completion of IPMI message. It can be done in different
> routes: One is in handled in IPMI user recv callback function. Another is
> handled in timeout function.
>     4. format the IPMI response and return it to ACPI AML code.
> 
> Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
> ---
>  drivers/acpi/Kconfig  |   12 +
>  drivers/acpi/Makefile |    1 +
>  drivers/acpi/ipmi.c   |  583 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 596 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/acpi/ipmi.c
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 93d2c79..23cd08a 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -204,6 +204,18 @@ 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
> +       default n
> +       select IPMI_HANDLER
> +       select IPMI_SI
> +       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:
> 
>  config ACPI_HOTPLUG_CPU
>         bool
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 7702118..61077b7 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_ACPI_BATTERY)    += battery.o
>  obj-$(CONFIG_ACPI_SBS)         += sbshc.o
>  obj-$(CONFIG_ACPI_SBS)         += sbs.o
>  obj-$(CONFIG_ACPI_POWER_METER) += power_meter.o
> +obj-$(CONFIG_ACPI_IPMI)                += ipmi.o
> 
>  # processor has its own "processor." module_param namespace
>  processor-y                    := processor_core.o processor_throttling.o
> diff --git a/drivers/acpi/ipmi.c b/drivers/acpi/ipmi.c
> new file mode 100644
> index 0000000..5c74936
> --- /dev/null
> +++ b/drivers/acpi/ipmi.c
> @@ -0,0 +1,583 @@
> +/*
> + *  ipmi.c - ACPI IPMI opregion
> + *
> + *  Copyright (C) 2009 Intel Corporation
> + *  Copyright (C) 2009 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>
> +
> +MODULE_AUTHOR("Zhao Yakui");
> +MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
> +MODULE_LICENSE("GPL");
> +
> +#define ACPI_IPMI_CLASS                        "IPMI"
> +#define ACPI_IPMI_DEVICE_NAME          "IPMI_dev"
> +#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;
> +       int if_type;
> +       /* 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;
> +};
> +
> +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 opration 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);
> +       return;
> +}
> +static void ipmi_destroy_tx_msg(struct acpi_ipmi_device *ipmi)
> +{
> +       struct acpi_ipmi_msg *tx_msg = NULL;
> +       int count = 20;
> +
> +       list_for_each_entry(tx_msg, &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 =
> +                       (struct acpi_ipmi_device *)user_msg_data;
> +       int msg_found = 0;
> +       struct acpi_ipmi_msg *tx_msg = NULL;
> +
> +       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;
> +       struct acpi_device *device;
> +       ipmi_user_t             user;
> +       int err;
> +
> +       if (list_empty(&driver_data.ipmi_devices))
> +               return;
> +
> +       list_for_each_entry(ipmi_device, &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;
> +
> +                       continue;
> +               }
> +               /*
> +                * In fact maybe the IPMI interface can be registered by
> +                * other methods. For example: SPMI, DMI, PCI
> +                * So we should also create the user interface.
> +                */
> +               err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
> +                                               ipmi_device, &user);
> +               if (err == 0)
> +                       ipmi_device->user_interface = user;
> +       }
> +       return;
> +}
> +
> +static void ipmi_bmc_gone(int iface)
> +{
> +       struct acpi_ipmi_device *ipmi_device;
> +
> +       if (list_empty(&driver_data.ipmi_devices))
> +               return;
> +
> +       list_for_each_entry(ipmi_device, &driver_data.ipmi_devices, head) {
> +               if (ipmi_device->user_interface) {
> +                       ipmi_destroy_user(ipmi_device->user_interface);
> +                       ipmi_device->user_interface = NULL;
> +                       /* we should also destory tx msg list */
> +                       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) {
> +               /* there doesn't exist user interface*/
> +               return AE_NOT_EXIST;
> +       }
> +       tx_msg = acpi_alloc_ipmi_msg(ipmi_device);
> +       if (!tx_msg) {
> +               /* no memory is allocated */
> +               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);
> +
> +end_label:
> +       acpi_format_ipmi_response(tx_msg, value, err);
> +       status = AE_OK;
> +       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_handlers(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_handlers(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;
> +       }
> +       set_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags);
> +       return 0;
> +}
> +
> +static int acpi_ipmi_add(struct acpi_device *device)
> +{
> +       struct acpi_ipmi_device *ipmi_device;
> +       acpi_handle handle;
> +       unsigned long long temp;
> +       acpi_status status;
> +       if (!device)
> +               return -EINVAL;
> +
> +       handle = device->handle;
> +       temp = 0;
> +       status = acpi_evaluate_integer(handle, "_IFT", NULL, &temp);
> +       if (ACPI_FAILURE(status)) {
> +               printk(KERN_DEBUG "Incorrect _IFT object for %s\n",
> +                               acpi_device_bid(device));
> +               return -ENODEV;
> +       }
> +       ipmi_device = kzalloc(sizeof(struct acpi_ipmi_device), GFP_KERNEL);
> +       if (!ipmi_device) {
> +               printk(KERN_DEBUG "Can't allocate memory space\n");
> +               return -ENOMEM;
> +       }
> +       ipmi_device->if_type = temp;
> +       switch (ipmi_device->if_type) {
> +       case 1:
> +       case 2:
> +       case 3:
> +               break;
> +       default:
> +               printk(KERN_DEBUG "Unknow IPMI:SI interface type %d\n",
> +                               ipmi_device->if_type);
> +               kfree(ipmi_device);
> +               return -EINVAL;
> +       }
> +       ipmi_device->handle = device->handle;
> +       ipmi_device->device = device;
> +       mutex_init(&ipmi_device->mutex_lock);
> +       INIT_LIST_HEAD(&ipmi_device->head);
> +       INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
> +
> +       if (ipmi_install_handlers(ipmi_device)) {
> +               /* can't register the IPMI opregion */
> +               kfree(ipmi_device);
> +               return -EINVAL;
> +       }
> +
> +       /* add it to the IPMI device list */
> +       list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
> +       device->driver_data = ipmi_device;
> +       return 0;
> +}
> +
> +static int acpi_ipmi_remove(struct acpi_device *device, int type)
> +{
> +       struct acpi_ipmi_device *ipmi_device;
> +
> +       ipmi_device = acpi_driver_data(device);
> +       if (!ipmi_device)
> +               return 0;
> +
> +       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)) {
> +               /* destroy the Tx_msg list */
> +               ipmi_destroy_tx_msg(ipmi_device);
> +       }
> +       ipmi_remove_handlers(ipmi_device);
> +       kfree(ipmi_device);
> +       device->driver_data = NULL;
> +       return 0;
> +}
> +
> +static const struct acpi_device_id ipmi_device_ids[] = {
> +       {"IPI0001", 0},
> +       {"", 0},
> +};
> +
> +static struct acpi_driver acpi_ipmi_driver = {
> +       .name = "ipmi",
> +       .class = ACPI_IPMI_CLASS,
> +       .ids = ipmi_device_ids,
> +       .ops = {
> +               .add = acpi_ipmi_add,
> +               .remove = acpi_ipmi_remove,
> +               },
> +};
> +
> +static int __init acpi_ipmi_init(void)
> +{
> +       int result = 0;
> +
> +       if (acpi_disabled)
> +               return result;
> +
> +       result = acpi_bus_register_driver(&acpi_ipmi_driver);
> +
> +       if (result)
> +               return result;
> +
> +       result = ipmi_smi_watcher_register(&driver_data.bmc_events);
> +
> +       if (result)
> +               acpi_bus_unregister_driver(&acpi_ipmi_driver);
> +
> +       return result;
> +}
> +
> +static void __exit acpi_ipmi_exit(void)
> +{
> +       if (acpi_disabled)
> +               return;
> +
> +       ipmi_smi_watcher_unregister(&driver_data.bmc_events);
> +       acpi_bus_unregister_driver(&acpi_ipmi_driver);
> +
> +       return;
> +}
> +
> +module_init(acpi_ipmi_init);
> +module_exit(acpi_ipmi_exit);
> --
> 1.5.4.5
>