Re: [PATCH_v8 2/2] ACPI: Add the IPMI opregion driver to enable ACPI to access BMC controller

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

On Tue, 2010-07-27 at 00:54 +0800, Bjorn Helgaas wrote:
> On Monday, July 26, 2010 08:46:05 am yakui.zhao@intel.com wrote:
> >
> >         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:
> 
> I've mentioned this three times already.  Will you please fix it?
> The sentence above is not complete.  It needs to say something like
> this:

Sorry that I miss the above comment as I am focused on the discussion of
hook function.

> 
>         To compile this driver as a module, choose M here:
>         the module will be called acpi_ipmi.
> 
> There are a couple other comments below that I've mentioned in the
> past, too, so don't stop reading here :-)
> 
> >  config ACPI_HOTPLUG_CPU
> >       bool
> > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > index 6ee3316..5ca31f1 100644
> > --- a/drivers/acpi/Makefile
> > +++ b/drivers/acpi/Makefile
> > @@ -67,5 +67,6 @@ 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 0000000..f5a9412
> > --- /dev/null
> > +++ b/drivers/acpi/acpi_ipmi.c
> > @@ -0,0 +1,548 @@
> > +/*
> > + *  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;
> > +     acpi_handle handle;
> > +     struct pnp_dev  *pnp_dev;
> > +     ipmi_user_t     user_interface;
> > +     struct mutex    mutex_lock;
> > +     int ipmi_ifnum; /* IPMI interface number */
> > +     long curr_msgid;
> > +     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 {
> > +     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);
> 
> Please reorder the function definitions below so you don't need
> these forward declarations (if possible).

thanks for the comment. 

I tried what you mentioned. But it will fail in compilation without the
forward declarations. So I use the forward declaration as used in other
code.(For example: drivers/hwmon/ibmaem.c)

> 
> > +
> > +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,
> > +     },
> > +};
> > +
> > +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->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 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_destroy_tx_msg(struct acpi_ipmi_device *ipmi)
> > +{
> > +     struct acpi_ipmi_msg *tx_msg, *temp;
> > +     int count = 20;
> > +     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 20 ticks to flush the tx message list */
> > +     while (count--) {
> > +             if (list_empty(&ipmi->tx_msg_list))
> > +                     break;
> > +             schedule_timeout(1);
> 
> I mentioned this before, too.  This timeout is meaningless because
> you don't know how long a tick is.  Please change this to something
> that is related to the tick length.  For example, compute the number
> of ticks using HZ or msec_to_jiffies().
> 

OK. I will add one time definition and then transfer it to the
corresponding jiffies.


> > +     }
> > +     if (!list_empty(&ipmi->tx_msg_list))
> > +             dev_warn(&pnp_dev->dev, "tx msg list is not NULL\n");
> > +
> 
> Remove this blank line.
> 
> > +}
> > +
> > +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;
> 
> You don't need a cast here because "user_msg_data" is a "void *".
> 
> > +     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, "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);
> > +             dev_warn(&pnp_dev->dev, "Incorrect MSG is found\n");
> 
> Is there a MSG ID or something you can include in the warning message?
> 
> > +             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;
> > +     struct pnp_dev *device;
> > +     ipmi_user_t             user;
> > +     int err;
> > +
> > +     if (list_empty(&driver_data.ipmi_devices))
> > +             return;
> 
> You don't need to check the list for empty before using
> list_for_each_entry().

OK. I will delete it.

> 
> > +
> > +     list_for_each_entry(ipmi_device, &driver_data.ipmi_devices, head) {
> > +             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;
> > +             }
> > +             device = ipmi_device->pnp_dev;
> > +             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;
> > +                     }
> > +
> > +                     break;
> > +             }
> > +     }
> > +}
> > +
> > +static void ipmi_bmc_gone(int iface)
> > +{
> > +     struct acpi_ipmi_device *ipmi_device, *temp;
> > +
> > +     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);
> > +                     break;
> > +             }
> > +     }
> > +}
> > +/* --------------------------------------------------------------------------
> > + *                   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 =
> > +                     (struct acpi_ipmi_device *) handler_context;
> 
> You don't need a cast here, since "handler_context" is a "void *".

OK. I can delete the redundant cast transform. In fact IMO it will be
easy to understand. 

> 
> > +     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)
> > +             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)) {
> > +             struct pnp_dev *pnp_dev = ipmi->pnp_dev;
> > +             dev_warn(&pnp_dev->dev, "Can't register IPMI opregion for %s\n",
> > +                                     pnp_dev_name(pnp_dev));
> > +             return -EINVAL;
> > +     }
> > +     set_bit(IPMI_FLAGS_HANDLER_INSTALL, &ipmi->flags);
> > +     return 0;
> > +}
> > +
> > +
> > +static int acpi_add_ipmi_device(struct pnp_dev *pnp_dev)
> > +{
> > +     struct acpi_ipmi_device *ipmi_device;
> > +     struct acpi_device *acpi_dev;
> > +
> > +     /* check whether it is already registered */
> > +     list_for_each_entry(ipmi_device, &driver_data.ipmi_devices, head) {
> > +             if (ipmi_device->pnp_dev == pnp_dev) {
> > +                     dev_warn(&pnp_dev->dev,
> > +                             "device is already installed\n");
> > +                     return NOTIFY_DONE;
> > +             }
> > +     }
> > +
> > +     ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
> > +     if (!ipmi_device)
> > +             return NOTIFY_DONE;
> > +
> > +     acpi_dev = pnp_acpi_device(pnp_dev);
> > +     INIT_LIST_HEAD(&ipmi_device->head);
> > +     ipmi_device->pnp_dev = pnp_dev;
> > +     ipmi_device->handle = acpi_dev->handle;
> > +     list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
> > +
> > +     mutex_init(&ipmi_device->mutex_lock);
> > +     INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
> > +     ipmi_install_handler(ipmi_device);
> > +
> > +     return NOTIFY_OK;
> > +}
> > +
> > +static int acpi_remove_ipmi_device(struct pnp_dev *pnp_dev)
> > +{
> > +     struct acpi_ipmi_device *ipmi_device, *temp;
> > +     int ret = NOTIFY_DONE;
> > +
> > +     list_for_each_entry_safe(ipmi_device, temp, &driver_data.ipmi_devices,
> > +                                     head) {
> > +             if (ipmi_device->pnp_dev != pnp_dev)
> > +                     continue;
> > +
> > +             /*
> > +              * 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;
> > +             }
> > +             list_del(&ipmi_device->head);
> > +
> > +             /* destroy the Tx_msg list */
> > +             if (!list_empty(&ipmi_device->tx_msg_list))
> > +                     ipmi_destroy_tx_msg(ipmi_device);
> > +
> > +             ipmi_remove_handler(ipmi_device);
> > +             kfree(ipmi_device);
> > +             ret = NOTIFY_OK;
> > +             break;
> > +     }
> > +     return ret;
> > +}
> > +
> > +
> > +static int acpi_ipmi_notifier(struct notifier_block *nb,
> > +                                    unsigned long event, void *data)
> > +{
> > +     struct pnp_dev *pnp_dev = data;
> > +     int ret = NOTIFY_DONE;
> > +
> > +     switch (event) {
> > +     case IPMI_PNP_ADD:
> > +             ret = acpi_add_ipmi_device(pnp_dev);
> > +             break;
> > +     case IPMI_PNP_REMOVE:
> > +             ret = acpi_remove_ipmi_device(pnp_dev);
> > +             break;
> > +     default:
> > +             dev_warn(&pnp_dev->dev, "Incorrect event\n");
> 
> Please print the invalid event value here.

OK. I will add it.

> 
> > +             break;
> > +     }
> > +     return ret;
> > +}
> > +
> > +static struct notifier_block acpi_ipmi_notifier_block = {
> > +     .notifier_call = acpi_ipmi_notifier,
> > +};
> > +
> > +static int __init acpi_ipmi_init(void)
> > +{
> > +     int result = 0;
> > +
> > +     if (acpi_disabled)
> > +             return result;
> > +
> > +     result = acpi_ipmi_notifier_register(&acpi_ipmi_notifier_block);
> > +     if (result)
> > +             return result;
> > +
> > +     result = ipmi_smi_watcher_register(&driver_data.bmc_events);
> > +
> > +     if (result)
> > +             acpi_ipmi_notifier_unregister(&acpi_ipmi_notifier_block);
> > +
> > +     return result;
> > +}
> > +
> > +static void __exit acpi_ipmi_exit(void)
> > +{
> > +     if (acpi_disabled)
> > +             return;
> > +
> > +     ipmi_smi_watcher_unregister(&driver_data.bmc_events);
> > +
> > +     acpi_ipmi_notifier_unregister(&acpi_ipmi_notifier_block);
> > +}
> > +
> > +module_init(acpi_ipmi_init);
> > +module_exit(acpi_ipmi_exit);
> >
> --
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