[RFC,1/2] IPMI/ACPI: Locate the IPMI system interface in ACPI namespace

Commit Message

Zhao, Yakui Sept. 29, 2009, 5:29 a.m. UTC

From: Zhao Yakui <[e-mail]>

According to the IPMI 2.0 spec the IPMI system interface can be located with
ACPI. One is located in SPMI table(Service Processor Management Interface
table). Another is located in ACPI namespace.
This patch is to locate the IPMI system interface in ACPI namespace and
register it.
It includes the following two steps:
   1. enumerate the ACPI device tree to find the IPMI system interface
	The IPMI device type is IPI0001. When the device is found, it
will continue to parse the corresponding resources.
        For example: 
		interface type (KCS, BT, SMIC) (SSIF is not supported)
		interrupt number and type (_GPE or GSI)
		Memory or IO base address
    2. register the IPMI system interface.
			

Signed-off-by: Zhao Yakui <[e-mail]>
---
 drivers/char/ipmi/ipmi_si_intf.c |  394 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 394 insertions(+)

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Comments

Bjorn Helgaas Sept. 29, 2009, 3:51 p.m. UTC | #1

On Monday 28 September 2009 11:29:53 pm [e-mail] wrote:
> From: Zhao Yakui <[e-mail]>
> 
> According to the IPMI 2.0 spec the IPMI system interface can be located with
> ACPI. One is located in SPMI table(Service Processor Management Interface
> table). Another is located in ACPI namespace.
> This patch is to locate the IPMI system interface in ACPI namespace and
> register it.
> It includes the following two steps:
>    1. enumerate the ACPI device tree to find the IPMI system interface
> 	The IPMI device type is IPI0001. When the device is found, it
> will continue to parse the corresponding resources.
>         For example: 
> 		interface type (KCS, BT, SMIC) (SSIF is not supported)
> 		interrupt number and type (_GPE or GSI)
> 		Memory or IO base address
>     2. register the IPMI system interface.

I echo Corey's coding style comments.  The lack of consistency makes
it hard to read and review.

I don't like the fact that in this patch, you use acpi_walk_namespace()
to look for an IPI0001 device, and in the second patch, you register a
driver for IPI0001 devices.  You're making two bindings -- the one
done "by hand" here, and the other done by acpi_bus_register_driver().
There should only be one binding between the IPI0001 device and a driver,
so somehow the code in these two patches should be integrated.

The acpi_parse_io_ports() function is big and complicated, and that
points out another problem.  We shouldn't have to write all that code
every time we write an ACPI device driver.

I think you should register a *PNP* driver for IPI0001 devices, not an
ACPI driver.  That way, you can take advantage of all the resource
parsing code in PNPACPI, and all the acpi_parse_io_ports() code would
go away.

There is a problem here, though, because you still need ACPI so you
can evaluate _IFT, _GPE, _SRV, etc.  I think you should fix this by
adding a PNP interface to get back the ACPI handle from a PNP device
(this interface would fail if the device is not a PNPACPI device).

Bjorn


> Signed-off-by: Zhao Yakui <[e-mail]>
> ---
>  drivers/char/ipmi/ipmi_si_intf.c |  394 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 394 insertions(+)
> 
> Index: linux-2.6/drivers/char/ipmi/ipmi_si_intf.c
> ===================================================================
> --- linux-2.6.orig/drivers/char/ipmi/ipmi_si_intf.c	2009-09-28 16:46:07.000000000 +0800
> +++ linux-2.6/drivers/char/ipmi/ipmi_si_intf.c	2009-09-29 13:18:17.000000000 +0800
> @@ -1813,6 +1813,35 @@
>   * are no more.
>   */
>  static int acpi_failure;
> +static LIST_HEAD(acpi_ipmi);
> +
> +struct acpi_device_ipmi {
> +	struct list_head link;
> +	u8 interfacetype;
> +	/*
> +	 * Bit 0 - SCI interrupt supported
> +	 * Bit 1 - I/O APIC/SAPIC
> +	 */
> +	u8	interrupttype;
> +	/*
> +	 * If bit 0 of InterruptType is set, then this is the SCI
> +	 * interrupt in the GPEx_STS register.
> +	 */
> +	u8	gpe;
> +	/*
> +	 * If bit 1 of InterruptType is set, then this is the I/O
> +	 * APIC/SAPIC interrupt.
> +	 */
> +	u32	global_interrupt;
> +
> +	/* The actual register address. */
> +	struct acpi_generic_address addr;
> +	struct acpi_generic_address sm_addr;
> +
> +	u16 ipmi_revision;
> +	u8 resource_count;
> +	struct device *dev;
> +};
>  
>  /* For GPE-type interrupts. */
>  static u32 ipmi_acpi_gpe(void *context)
> @@ -2002,6 +2031,367 @@
>  	return 0;
>  }
>  
> +static __devinit int try_init_acpi_device(struct acpi_device_ipmi *spmi)
> +{
> +	struct smi_info  *info;
> +	u8 		 addr_space;
> +
> +	if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
> +		addr_space = IPMI_MEM_ADDR_SPACE;
> +	else
> +		addr_space = IPMI_IO_ADDR_SPACE;
> +
> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> +	if (!info) {
> +		printk(KERN_ERR "ipmi_si: Could not allocate SI data (3)\n");
> +		return -ENOMEM;
> +	}
> +
> +	info->addr_source = "ACPI";
> +
> +	/* Figure out the interface type. */
> +	switch (spmi->interfacetype) {
> +	case 1:	/* KCS */
> +		info->si_type = SI_KCS;
> +		break;
> +	case 2:	/* SMIC */
> +		info->si_type = SI_SMIC;
> +		break;
> +	case 3:	/* BT */
> +		info->si_type = SI_BT;
> +		break;
> +	default:
> +		printk(KERN_INFO "ipmi_si: Unknown ACPI/SPMI SI type %d\n",
> +			spmi->interfacetype);
> +		kfree(info);
> +		return -EIO;
> +	}
> +
> +	if (spmi->interrupttype & 1) {
> +		/* We've got a GPE interrupt. */
> +		info->irq = spmi->gpe;
> +		info->irq_setup = acpi_gpe_irq_setup;
> +	} else if (spmi->interrupttype & 2) {
> +		/* We've got an APIC/SAPIC interrupt. */
> +		info->irq = spmi->global_interrupt;
> +		info->irq_setup = std_irq_setup;
> +	} else {
> +		/* Use the default interrupt setting. */
> +		info->irq = 0;
> +		info->irq_setup = NULL;
> +	}
> +
> +	if (spmi->addr.bit_width) {
> +		/* A (hopefully) properly formed register bit width. */
> +		info->io.regspacing = spmi->addr.bit_width / 8;
> +	} else {
> +		info->io.regspacing = DEFAULT_REGSPACING;
> +	}
> +	info->io.regsize = info->io.regspacing;
> +	info->io.regshift = spmi->addr.bit_offset;
> +
> +	if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
> +		info->io_setup = mem_setup;
> +		info->io.addr_type = IPMI_MEM_ADDR_SPACE;
> +	} else if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
> +		info->io_setup = port_setup;
> +		info->io.addr_type = IPMI_IO_ADDR_SPACE;
> +	} else {
> +		kfree(info);
> +		printk(KERN_WARNING
> +		       "ipmi_si: Unknown ACPI I/O Address type\n");
> +		return -EIO;
> +	}
> +	info->io.addr_data = spmi->addr.address;
> +	info->dev = spmi->dev;
> +
> +	try_smi_init(info);
> +
> +	return 0;
> +}
> +
> +static acpi_status
> +acpi_parse_io_ports(struct acpi_resource *resource, void *context)
> +{
> +	struct acpi_device_ipmi *p_ipmi = context;
> +
> +	if (resource->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ ||
> +		resource->type == ACPI_RESOURCE_TYPE_IRQ) {
> +		unsigned int irq_number;
> +		if (p_ipmi->interrupttype) {
> +			/*
> +			 * If it already support the interrupt through GPE,
> +			 * it is unnecessary to get this interrupt again.
> +			 */
> +			printk(KERN_WARNING "Interrupt through GPE is already"
> +				" supported.\n");
> +			return AE_OK;
> +		}
> +		if (resource->type == ACPI_RESOURCE_TYPE_IRQ) {
> +			struct acpi_resource_irq *irq;
> +			irq = &resource->data.irq;
> +			if (irq->interrupt_count != 1) {
> +				printk(KERN_WARNING "incorrect IRQ is "
> +					"defined in _CRS\n");
> +				return AE_OK;
> +			}
> +			irq_number = irq->interrupts[0];
> +		} else {
> +			struct acpi_resource_extended_irq *extended_irq;
> +			extended_irq = &resource->data.extended_irq;
> +			if (extended_irq->interrupt_count != 1) {
> +				printk(KERN_WARNING "incorrect IRQ is "
> +					"defined in _CRS\n");
> +				return AE_OK;
> +			}
> +			irq_number = extended_irq->interrupts[0];
> +		}
> +		p_ipmi->global_interrupt = irq_number;
> +		if (p_ipmi->global_interrupt) {
> +			/* GSI interrupt type */
> +			p_ipmi->interrupttype |= 0x02;
> +		}
> +		return AE_OK;
> +	}
> +	if (resource->type == ACPI_RESOURCE_TYPE_IO ||
> +		resource->type == ACPI_RESOURCE_TYPE_FIXED_IO) {
> +		u16 address;
> +		struct acpi_resource_io *io;
> +		struct acpi_resource_fixed_io *fixed_io;
> +
> +		fixed_io = &resource->data.fixed_io;
> +		if (p_ipmi->resource_count) {
> +			/*
> +			 * Multiply definitions of IO/memory address are
> +			 * obtained. It is incorrect. We will continue
> +			 * to use the first IO/memory definition.
> +			 * If not correct, please fix me.
> +			 */
> +			return AE_OK;
> +		}
> +		if (resource->type == ACPI_RESOURCE_TYPE_IO) {
> +			io = &resource->data.io;
> +			if (!io->minimum) {
> +				/* when IO address is zero, return */
> +				return AE_OK;
> +			}
> +			address = io->minimum;
> +		} else {
> +			fixed_io = &resource->data.fixed_io;
> +			if (!fixed_io->address)
> +				return AE_OK;
> +			address = fixed_io->address;
> +		}
> +		p_ipmi->resource_count++;
> +		p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
> +		p_ipmi->addr.address = address;
> +		return AE_OK;
> +	}
> +
> +	if (resource->type == ACPI_RESOURCE_TYPE_MEMORY32 ||
> +		resource->type == ACPI_RESOURCE_TYPE_MEMORY24 ||
> +		resource->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
> +		u32 address;
> +		if (p_ipmi->resource_count) {
> +			/*
> +			 * Multiply definitions of IO/memory address are
> +			 * obtained. It is incorrect. We will continue
> +			 * to use the first IO/memory definition.
> +			 * If not correct, please fix me.
> +			 */
> +			return AE_OK;
> +		}
> +		if (resource->type == ACPI_RESOURCE_TYPE_MEMORY32) {
> +			struct acpi_resource_memory32 *memory32;
> +			memory32 = &resource->data.memory32;
> +			address = memory32->minimum;
> +		} else if (resource->type == ACPI_RESOURCE_TYPE_MEMORY24) {
> +			struct acpi_resource_memory24 *memory24;
> +			memory24 = &resource->data.memory24;
> +			address = memory24->minimum;
> +		} else {
> +			struct acpi_resource_fixed_memory32 *fixed_memory32;
> +			fixed_memory32 = &resource->data.fixed_memory32;
> +			address = fixed_memory32->address;
> +		}
> +		p_ipmi->resource_count++;
> +		p_ipmi->addr.address = (u64) address;
> +		p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_MEMORY;
> +		return AE_OK;
> +	}
> +	if (resource->type == ACPI_RESOURCE_TYPE_ADDRESS16 ||
> +		resource->type == ACPI_RESOURCE_TYPE_ADDRESS32 ||
> +		resource->type == ACPI_RESOURCE_TYPE_ADDRESS64) {
> +		struct acpi_resource_address64 address64;
> +		acpi_resource_to_address64(resource, &address64);
> +		if (p_ipmi->resource_count) {
> +			/*
> +			 * Multiply definitions of IO/memory address are
> +			 * obtained. It is incorrect. We will continue
> +			 * to use the first IO/memory definition.
> +			 * If not correct, please fix me.
> +			 */
> +			return AE_OK;
> +		}
> +		if (address64.resource_type != ACPI_MEMORY_RANGE &&
> +			address64.resource_type != ACPI_IO_RANGE) {
> +			/* ignore the incorrect resource type */
> +			return AE_OK;
> +		}
> +		p_ipmi->addr.address = address64.minimum;
> +		p_ipmi->resource_count++;
> +		if (address64.resource_type == ACPI_MEMORY_RANGE)
> +			p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_MEMORY;
> +		else
> +			p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
> +
> +		return AE_OK;
> +	}
> +
> +	return AE_OK;
> +}
> +
> +/*
> + *  acpi_parse_bmc_resource -- parse the BMC resources from ACPI
> + *  @p_ipmi: the memory to store the BCM resource
> + *  @handle: ACPI device handle
> + */
> +static int acpi_parse_bmc_resource(struct acpi_device_ipmi *p_ipmi,
> +			acpi_handle handle)
> +{
> +	int parse_ok = false;
> +	unsigned long long	temp_data;
> +	acpi_status status;
> +
> +	/* According to IPMI spec there should exist the _IFT method
> +	 * for the IPMI device. So when there is no _IFT, it is regarded
> +	 * as the incorrect BMC device and won't parse the resource again.
> +	 */
> +	status = acpi_evaluate_integer(handle, "_IFT", NULL, &temp_data);
> +	if (ACPI_FAILURE(status))
> +		return parse_ok;
> +
> +	p_ipmi->interfacetype = temp_data;
> +	/* Figure out the interface type. If the interface type is not
> +	 * KCS/SMIC/BT, it is regared as the incorrect IPMI device.
> +	 * Of course the SSIF interface type is also defined, but we
> +	 * can't handle it. So it is not supported */
> +	switch (temp_data) {
> +	case 1:	/* KCS */
> +	case 2:	/* SMIC */
> +	case 3:	/* BT */
> +		break;
> +	default:
> +		printk(KERN_INFO "ipmi_si: Unknown ACPI/SPMI SI type %d\n",
> +			p_ipmi->interfacetype);
> +		return parse_ok;
> +	}
> +	/* check whether there exists the _GPE method. If it exists, it
> +	 * means that interrupt through GPE is supported.
> +	 */
> +	temp_data = 0;
> +	status = acpi_evaluate_integer(handle, "_GPE", NULL, &temp_data);
> +	if (ACPI_SUCCESS(status)) {
> +		p_ipmi->gpe = temp_data;
> +		/* set the GPE interrupt type */
> +		p_ipmi->interrupttype |= 0x01;
> +	}
> +	/* get the IPMI revision */
> +	temp_data = 0;
> +	status = acpi_evaluate_integer(handle, "_SRV", NULL,  &temp_data);
> +	if (ACPI_SUCCESS(status))
> +		p_ipmi->ipmi_revision = temp_data;
> +
> +	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> +				acpi_parse_io_ports, p_ipmi);
> +	if (ACPI_FAILURE(status)) {
> +		printk(KERN_WARNING "Can't parse the _CRS object \n");
> +		return parse_ok;
> +	}
> +	if (!p_ipmi->resource_count) {
> +		/* The incorrect IO/Memory address is parsed */
> +		printk(KERN_ERR "Incorrect IO/Memory address is parsed\n");
> +		return parse_ok;
> +	}
> +	parse_ok = true;
> +
> +	return parse_ok;
> +}
> +
> +const struct acpi_device_id ipmi_ids[] = {
> +	{"IPI0001", 0},
> +	{"", 0},
> +};
> +
> +/*
> + * acpi_check_bmc_device -- check whether @handle is a BMC device and then
> + *		get its corresponding resource. For example: IO/Mem
> + *		address, interface type
> + * @handle: ACPI device handle
> + * @level : depth in the ACPI namespace tree
> + * @context: the number of bmc device. In theory there is not more than
> + * 	one ACPI BMC device.
> + * @rv: a return value to fill if desired (Not use)
> + */
> +static acpi_status
> +acpi_check_bmc_device(acpi_handle handle, u32 level, void *context,
> +			void **return_value)
> +{
> +	struct acpi_device *acpi_dev;
> +	struct acpi_device_ipmi *p_ipmi = NULL;
> +	int *count = (int *)context;
> +
> +	acpi_dev = NULL;
> +	/* Get the acpi device for device handle */
> +	if (acpi_bus_get_device(handle, &acpi_dev) || !acpi_dev) {
> +		/* If there is no ACPI device for handle, return */
> +		return AE_OK;
> +	}
> +
> +	if (acpi_match_device_ids(acpi_dev, ipmi_ids))
> +		return AE_OK;
> +
> +	p_ipmi = kzalloc(sizeof(*p_ipmi), GFP_KERNEL);
> +	if (!p_ipmi) {
> +		printk(KERN_ERR "Can't allocate memory for IPMI device\n");
> +		return AE_OK;
> +	}
> +	p_ipmi->dev = &acpi_dev->dev;
> +	if (!acpi_parse_bmc_resource(p_ipmi, handle)) {
> +		kfree(p_ipmi);
> +	} else {
> +		list_add_tail(&p_ipmi->link, &acpi_ipmi);
> +		*count = *count + 1;
> +	}
> +
> +	return AE_OK;
> +}
> +
> +static __devinit void acpi_device_find_bmc(void)
> +{
> +	acpi_status      status;
> +	int              device_count = 0;
> +	struct acpi_device_ipmi *p_ipmi, *p_ipmi2;
> +
> +	if (acpi_disabled)
> +		return;
> +
> +	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
> +				ACPI_UINT32_MAX,
> +				acpi_check_bmc_device, &device_count, NULL);
> +	if (!device_count) {
> +		/* when no IPMI device is found in ACPI namespace, return */
> +		return;
> +	}
> +	list_for_each_entry_safe(p_ipmi, p_ipmi2, &acpi_ipmi, link) {
> +		try_init_acpi_device(p_ipmi);
> +		list_del(&p_ipmi->link);
> +		kfree(p_ipmi);
> +	}
> +
> +	return;
> +}
> +
>  static __devinit void acpi_find_bmc(void)
>  {
>  	acpi_status      status;
> @@ -2014,6 +2404,7 @@
>  	if (acpi_failure)
>  		return;
>  
> +	/* locate the IPMI system interface in ACPI SPMI table */
>  	for (i = 0; ; i++) {
>  		status = acpi_get_table(ACPI_SIG_SPMI, i+1,
>  					(struct acpi_table_header **)&spmi);
> @@ -2022,6 +2413,9 @@
>  
>  		try_init_acpi(spmi);
>  	}
> +
> +	/* locate the IPMI system interface in ACPI device */
> +	acpi_device_find_bmc();
>  }
>  #endif
>  
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Patch

Index: linux-2.6/drivers/char/ipmi/ipmi_si_intf.c
===================================================================
--- linux-2.6.orig/drivers/char/ipmi/ipmi_si_intf.c	2009-09-28 16:46:07.000000000 +0800
+++ linux-2.6/drivers/char/ipmi/ipmi_si_intf.c	2009-09-29 13:18:17.000000000 +0800
@@ -1813,6 +1813,35 @@ 
  * are no more.
  */
 static int acpi_failure;
+static LIST_HEAD(acpi_ipmi);
+
+struct acpi_device_ipmi {
+	struct list_head link;
+	u8 interfacetype;
+	/*
+	 * Bit 0 - SCI interrupt supported
+	 * Bit 1 - I/O APIC/SAPIC
+	 */
+	u8	interrupttype;
+	/*
+	 * If bit 0 of InterruptType is set, then this is the SCI
+	 * interrupt in the GPEx_STS register.
+	 */
+	u8	gpe;
+	/*
+	 * If bit 1 of InterruptType is set, then this is the I/O
+	 * APIC/SAPIC interrupt.
+	 */
+	u32	global_interrupt;
+
+	/* The actual register address. */
+	struct acpi_generic_address addr;
+	struct acpi_generic_address sm_addr;
+
+	u16 ipmi_revision;
+	u8 resource_count;
+	struct device *dev;
+};
 
 /* For GPE-type interrupts. */
 static u32 ipmi_acpi_gpe(void *context)
@@ -2002,6 +2031,367 @@ 
 	return 0;
 }
 
+static __devinit int try_init_acpi_device(struct acpi_device_ipmi *spmi)
+{
+	struct smi_info  *info;
+	u8 		 addr_space;
+
+	if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		addr_space = IPMI_MEM_ADDR_SPACE;
+	else
+		addr_space = IPMI_IO_ADDR_SPACE;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		printk(KERN_ERR "ipmi_si: Could not allocate SI data (3)\n");
+		return -ENOMEM;
+	}
+
+	info->addr_source = "ACPI";
+
+	/* Figure out the interface type. */
+	switch (spmi->interfacetype) {
+	case 1:	/* KCS */
+		info->si_type = SI_KCS;
+		break;
+	case 2:	/* SMIC */
+		info->si_type = SI_SMIC;
+		break;
+	case 3:	/* BT */
+		info->si_type = SI_BT;
+		break;
+	default:
+		printk(KERN_INFO "ipmi_si: Unknown ACPI/SPMI SI type %d\n",
+			spmi->interfacetype);
+		kfree(info);
+		return -EIO;
+	}
+
+	if (spmi->interrupttype & 1) {
+		/* We've got a GPE interrupt. */
+		info->irq = spmi->gpe;
+		info->irq_setup = acpi_gpe_irq_setup;
+	} else if (spmi->interrupttype & 2) {
+		/* We've got an APIC/SAPIC interrupt. */
+		info->irq = spmi->global_interrupt;
+		info->irq_setup = std_irq_setup;
+	} else {
+		/* Use the default interrupt setting. */
+		info->irq = 0;
+		info->irq_setup = NULL;
+	}
+
+	if (spmi->addr.bit_width) {
+		/* A (hopefully) properly formed register bit width. */
+		info->io.regspacing = spmi->addr.bit_width / 8;
+	} else {
+		info->io.regspacing = DEFAULT_REGSPACING;
+	}
+	info->io.regsize = info->io.regspacing;
+	info->io.regshift = spmi->addr.bit_offset;
+
+	if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+		info->io_setup = mem_setup;
+		info->io.addr_type = IPMI_MEM_ADDR_SPACE;
+	} else if (spmi->addr.space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+		info->io_setup = port_setup;
+		info->io.addr_type = IPMI_IO_ADDR_SPACE;
+	} else {
+		kfree(info);
+		printk(KERN_WARNING
+		       "ipmi_si: Unknown ACPI I/O Address type\n");
+		return -EIO;
+	}
+	info->io.addr_data = spmi->addr.address;
+	info->dev = spmi->dev;
+
+	try_smi_init(info);
+
+	return 0;
+}
+
+static acpi_status
+acpi_parse_io_ports(struct acpi_resource *resource, void *context)
+{
+	struct acpi_device_ipmi *p_ipmi = context;
+
+	if (resource->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ ||
+		resource->type == ACPI_RESOURCE_TYPE_IRQ) {
+		unsigned int irq_number;
+		if (p_ipmi->interrupttype) {
+			/*
+			 * If it already support the interrupt through GPE,
+			 * it is unnecessary to get this interrupt again.
+			 */
+			printk(KERN_WARNING "Interrupt through GPE is already"
+				" supported.\n");
+			return AE_OK;
+		}
+		if (resource->type == ACPI_RESOURCE_TYPE_IRQ) {
+			struct acpi_resource_irq *irq;
+			irq = &resource->data.irq;
+			if (irq->interrupt_count != 1) {
+				printk(KERN_WARNING "incorrect IRQ is "
+					"defined in _CRS\n");
+				return AE_OK;
+			}
+			irq_number = irq->interrupts[0];
+		} else {
+			struct acpi_resource_extended_irq *extended_irq;
+			extended_irq = &resource->data.extended_irq;
+			if (extended_irq->interrupt_count != 1) {
+				printk(KERN_WARNING "incorrect IRQ is "
+					"defined in _CRS\n");
+				return AE_OK;
+			}
+			irq_number = extended_irq->interrupts[0];
+		}
+		p_ipmi->global_interrupt = irq_number;
+		if (p_ipmi->global_interrupt) {
+			/* GSI interrupt type */
+			p_ipmi->interrupttype |= 0x02;
+		}
+		return AE_OK;
+	}
+	if (resource->type == ACPI_RESOURCE_TYPE_IO ||
+		resource->type == ACPI_RESOURCE_TYPE_FIXED_IO) {
+		u16 address;
+		struct acpi_resource_io *io;
+		struct acpi_resource_fixed_io *fixed_io;
+
+		fixed_io = &resource->data.fixed_io;
+		if (p_ipmi->resource_count) {
+			/*
+			 * Multiply definitions of IO/memory address are
+			 * obtained. It is incorrect. We will continue
+			 * to use the first IO/memory definition.
+			 * If not correct, please fix me.
+			 */
+			return AE_OK;
+		}
+		if (resource->type == ACPI_RESOURCE_TYPE_IO) {
+			io = &resource->data.io;
+			if (!io->minimum) {
+				/* when IO address is zero, return */
+				return AE_OK;
+			}
+			address = io->minimum;
+		} else {
+			fixed_io = &resource->data.fixed_io;
+			if (!fixed_io->address)
+				return AE_OK;
+			address = fixed_io->address;
+		}
+		p_ipmi->resource_count++;
+		p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
+		p_ipmi->addr.address = address;
+		return AE_OK;
+	}
+
+	if (resource->type == ACPI_RESOURCE_TYPE_MEMORY32 ||
+		resource->type == ACPI_RESOURCE_TYPE_MEMORY24 ||
+		resource->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
+		u32 address;
+		if (p_ipmi->resource_count) {
+			/*
+			 * Multiply definitions of IO/memory address are
+			 * obtained. It is incorrect. We will continue
+			 * to use the first IO/memory definition.
+			 * If not correct, please fix me.
+			 */
+			return AE_OK;
+		}
+		if (resource->type == ACPI_RESOURCE_TYPE_MEMORY32) {
+			struct acpi_resource_memory32 *memory32;
+			memory32 = &resource->data.memory32;
+			address = memory32->minimum;
+		} else if (resource->type == ACPI_RESOURCE_TYPE_MEMORY24) {
+			struct acpi_resource_memory24 *memory24;
+			memory24 = &resource->data.memory24;
+			address = memory24->minimum;
+		} else {
+			struct acpi_resource_fixed_memory32 *fixed_memory32;
+			fixed_memory32 = &resource->data.fixed_memory32;
+			address = fixed_memory32->address;
+		}
+		p_ipmi->resource_count++;
+		p_ipmi->addr.address = (u64) address;
+		p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_MEMORY;
+		return AE_OK;
+	}
+	if (resource->type == ACPI_RESOURCE_TYPE_ADDRESS16 ||
+		resource->type == ACPI_RESOURCE_TYPE_ADDRESS32 ||
+		resource->type == ACPI_RESOURCE_TYPE_ADDRESS64) {
+		struct acpi_resource_address64 address64;
+		acpi_resource_to_address64(resource, &address64);
+		if (p_ipmi->resource_count) {
+			/*
+			 * Multiply definitions of IO/memory address are
+			 * obtained. It is incorrect. We will continue
+			 * to use the first IO/memory definition.
+			 * If not correct, please fix me.
+			 */
+			return AE_OK;
+		}
+		if (address64.resource_type != ACPI_MEMORY_RANGE &&
+			address64.resource_type != ACPI_IO_RANGE) {
+			/* ignore the incorrect resource type */
+			return AE_OK;
+		}
+		p_ipmi->addr.address = address64.minimum;
+		p_ipmi->resource_count++;
+		if (address64.resource_type == ACPI_MEMORY_RANGE)
+			p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_MEMORY;
+		else
+			p_ipmi->addr.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
+
+		return AE_OK;
+	}
+
+	return AE_OK;
+}
+
+/*
+ *  acpi_parse_bmc_resource -- parse the BMC resources from ACPI
+ *  @p_ipmi: the memory to store the BCM resource
+ *  @handle: ACPI device handle
+ */
+static int acpi_parse_bmc_resource(struct acpi_device_ipmi *p_ipmi,
+			acpi_handle handle)
+{
+	int parse_ok = false;
+	unsigned long long	temp_data;
+	acpi_status status;
+
+	/* According to IPMI spec there should exist the _IFT method
+	 * for the IPMI device. So when there is no _IFT, it is regarded
+	 * as the incorrect BMC device and won't parse the resource again.
+	 */
+	status = acpi_evaluate_integer(handle, "_IFT", NULL, &temp_data);
+	if (ACPI_FAILURE(status))
+		return parse_ok;
+
+	p_ipmi->interfacetype = temp_data;
+	/* Figure out the interface type. If the interface type is not
+	 * KCS/SMIC/BT, it is regared as the incorrect IPMI device.
+	 * Of course the SSIF interface type is also defined, but we
+	 * can't handle it. So it is not supported */
+	switch (temp_data) {
+	case 1:	/* KCS */
+	case 2:	/* SMIC */
+	case 3:	/* BT */
+		break;
+	default:
+		printk(KERN_INFO "ipmi_si: Unknown ACPI/SPMI SI type %d\n",
+			p_ipmi->interfacetype);
+		return parse_ok;
+	}
+	/* check whether there exists the _GPE method. If it exists, it
+	 * means that interrupt through GPE is supported.
+	 */
+	temp_data = 0;
+	status = acpi_evaluate_integer(handle, "_GPE", NULL, &temp_data);
+	if (ACPI_SUCCESS(status)) {
+		p_ipmi->gpe = temp_data;
+		/* set the GPE interrupt type */
+		p_ipmi->interrupttype |= 0x01;
+	}
+	/* get the IPMI revision */
+	temp_data = 0;
+	status = acpi_evaluate_integer(handle, "_SRV", NULL,  &temp_data);
+	if (ACPI_SUCCESS(status))
+		p_ipmi->ipmi_revision = temp_data;
+
+	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+				acpi_parse_io_ports, p_ipmi);
+	if (ACPI_FAILURE(status)) {
+		printk(KERN_WARNING "Can't parse the _CRS object \n");
+		return parse_ok;
+	}
+	if (!p_ipmi->resource_count) {
+		/* The incorrect IO/Memory address is parsed */
+		printk(KERN_ERR "Incorrect IO/Memory address is parsed\n");
+		return parse_ok;
+	}
+	parse_ok = true;
+
+	return parse_ok;
+}
+
+const struct acpi_device_id ipmi_ids[] = {
+	{"IPI0001", 0},
+	{"", 0},
+};
+
+/*
+ * acpi_check_bmc_device -- check whether @handle is a BMC device and then
+ *		get its corresponding resource. For example: IO/Mem
+ *		address, interface type
+ * @handle: ACPI device handle
+ * @level : depth in the ACPI namespace tree
+ * @context: the number of bmc device. In theory there is not more than
+ * 	one ACPI BMC device.
+ * @rv: a return value to fill if desired (Not use)
+ */
+static acpi_status
+acpi_check_bmc_device(acpi_handle handle, u32 level, void *context,
+			void **return_value)
+{
+	struct acpi_device *acpi_dev;
+	struct acpi_device_ipmi *p_ipmi = NULL;
+	int *count = (int *)context;
+
+	acpi_dev = NULL;
+	/* Get the acpi device for device handle */
+	if (acpi_bus_get_device(handle, &acpi_dev) || !acpi_dev) {
+		/* If there is no ACPI device for handle, return */
+		return AE_OK;
+	}
+
+	if (acpi_match_device_ids(acpi_dev, ipmi_ids))
+		return AE_OK;
+
+	p_ipmi = kzalloc(sizeof(*p_ipmi), GFP_KERNEL);
+	if (!p_ipmi) {
+		printk(KERN_ERR "Can't allocate memory for IPMI device\n");
+		return AE_OK;
+	}
+	p_ipmi->dev = &acpi_dev->dev;
+	if (!acpi_parse_bmc_resource(p_ipmi, handle)) {
+		kfree(p_ipmi);
+	} else {
+		list_add_tail(&p_ipmi->link, &acpi_ipmi);
+		*count = *count + 1;
+	}
+
+	return AE_OK;
+}
+
+static __devinit void acpi_device_find_bmc(void)
+{
+	acpi_status      status;
+	int              device_count = 0;
+	struct acpi_device_ipmi *p_ipmi, *p_ipmi2;
+
+	if (acpi_disabled)
+		return;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+				ACPI_UINT32_MAX,
+				acpi_check_bmc_device, &device_count, NULL);
+	if (!device_count) {
+		/* when no IPMI device is found in ACPI namespace, return */
+		return;
+	}
+	list_for_each_entry_safe(p_ipmi, p_ipmi2, &acpi_ipmi, link) {
+		try_init_acpi_device(p_ipmi);
+		list_del(&p_ipmi->link);
+		kfree(p_ipmi);
+	}
+
+	return;
+}
+
 static __devinit void acpi_find_bmc(void)
 {
 	acpi_status      status;
@@ -2014,6 +2404,7 @@ 
 	if (acpi_failure)
 		return;
 
+	/* locate the IPMI system interface in ACPI SPMI table */
 	for (i = 0; ; i++) {
 		status = acpi_get_table(ACPI_SIG_SPMI, i+1,
 					(struct acpi_table_header **)&spmi);
@@ -2022,6 +2413,9 @@ 
 
 		try_init_acpi(spmi);
 	}
+
+	/* locate the IPMI system interface in ACPI device */
+	acpi_device_find_bmc();
 }
 #endif