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

[Corey Minyard <minyard@acm.org>]

Len Brown wrote:
> On Wed, 9 Dec 2009, Bjorn Helgaas wrote:
>
>   
>> On Tuesday 08 December 2009 06:58:45 pm yakui.zhao@intel.com wrote:
>>     
>>> 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.
>>>       
>> I think this should be part of the ipmi_si_intf module, not a separate
>> module.  This opregion code is of no use without ipmi_si_intf.  The
>> opregion code can still be under its own config option, but I don't
>> see the value in having it be a separate module.
>>     
>
>
> I agree.  Corey?
>   
Yes, that is a good idea.

-corey

> thanks,
> -Len Brown, Intel Open Source technology Center
>
>   
>> The opregion code should definitely not use acpi_bus_register_driver()
>> to claim IPI0001 devices.  The ipmi_si_intf driver already uses
>> pnp_register_driver() to claim IPI0001 devices.  The fact that Linux
>> allows two drivers to claim the same device (one via pnp_register_driver()
>> and the other via acpi_bus_register_driver()) is a defect in Linux, and
>> we shouldn't take advantage of that.
>>
>> Bjorn
>>
>>     
>>> 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);
>>>       
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