path: root/drivers/staging/unisys/visorbus/visorchipset.c

/* visorchipset_main.c
 *
 * Copyright (C) 2010 - 2015 UNISYS CORPORATION
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * 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, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 */

#include <linux/acpi.h>
#include <linux/cdev.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/nls.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/uuid.h>
#include <linux/crash_dump.h>

#include "version.h"
#include "visorbus.h"
#include "visorbus_private.h"
#include "vmcallinterface.h"

#define CURRENT_FILE_PC VISOR_CHIPSET_PC_visorchipset_main_c

#define POLLJIFFIES_CONTROLVMCHANNEL_FAST   1
#define POLLJIFFIES_CONTROLVMCHANNEL_SLOW 100

#define MAX_CONTROLVM_PAYLOAD_BYTES (1024 * 128)

#define VISORCHIPSET_MMAP_CONTROLCHANOFFSET	0x00000000

#define UNISYS_SPAR_LEAF_ID 0x40000000

/* The s-Par leaf ID returns "UnisysSpar64" encoded across ebx, ecx, edx */
#define UNISYS_SPAR_ID_EBX 0x73696e55
#define UNISYS_SPAR_ID_ECX 0x70537379
#define UNISYS_SPAR_ID_EDX 0x34367261

/*
 * Module parameters
 */
static int visorchipset_major;

static int
visorchipset_open(struct inode *inode, struct file *file)
{
	unsigned int minor_number = iminor(inode);

	if (minor_number)
		return -ENODEV;
	file->private_data = NULL;
	return 0;
}

static int
visorchipset_release(struct inode *inode, struct file *file)
{
	return 0;
}

/*
 * When the controlvm channel is idle for at least MIN_IDLE_SECONDS,
 * we switch to slow polling mode. As soon as we get a controlvm
 * message, we switch back to fast polling mode.
 */
#define MIN_IDLE_SECONDS 10
static unsigned long poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_FAST;
/* when we got our last controlvm message */
static unsigned long most_recent_message_jiffies;

struct parser_context {
	unsigned long allocbytes;
	unsigned long param_bytes;
	u8 *curr;
	unsigned long bytes_remaining;
	bool byte_stream;
	char data[0];
};

static struct delayed_work periodic_controlvm_work;

static struct cdev file_cdev;
static struct visorchannel **file_controlvm_channel;

static struct visorchannel *controlvm_channel;

/* Manages the request payload in the controlvm channel */
struct visor_controlvm_payload_info {
	u8 *ptr;		/* pointer to base address of payload pool */
	u64 offset;		/*
				 * offset from beginning of controlvm
				 * channel to beginning of payload * pool
				 */
	u32 bytes;		/* number of bytes in payload pool */
};

static struct visor_controlvm_payload_info controlvm_payload_info;
static unsigned long controlvm_payload_bytes_buffered;

/*
 * The following globals are used to handle the scenario where we are unable to
 * offload the payload from a controlvm message due to memory requirements. In
 * this scenario, we simply stash the controlvm message, then attempt to
 * process it again the next time controlvm_periodic_work() runs.
 */
static struct controlvm_message controlvm_pending_msg;
static bool controlvm_pending_msg_valid;

/*
 * This describes a buffer and its current state of transfer (e.g., how many
 * bytes have already been supplied as putfile data, and how many bytes are
 * remaining) for a putfile_request.
 */
struct putfile_active_buffer {
	/* a payload from a controlvm message, containing a file data buffer */
	struct parser_context *parser_ctx;
	/* points within data area of parser_ctx to next byte of data */
	size_t bytes_remaining;
};

#define PUTFILE_REQUEST_SIG 0x0906101302281211
/*
 * This identifies a single remote --> local CONTROLVM_TRANSMIT_FILE
 * conversation. Structs of this type are dynamically linked into
 * <Putfile_request_list>.
 */
struct putfile_request {
	u64 sig;		/* PUTFILE_REQUEST_SIG */

	/* header from original TransmitFile request */
	struct controlvm_message_header controlvm_header;

	/* link to next struct putfile_request */
	struct list_head next_putfile_request;

	/*
	 * head of putfile_buffer_entry list, which describes the data to be
	 * supplied as putfile data;
	 * - this list is added to when controlvm messages come in that supply
	 * file data
	 * - this list is removed from via the hotplug program that is actually
	 * consuming these buffers to write as file data
	 */
	struct list_head input_buffer_list;
	spinlock_t req_list_lock;	/* lock for input_buffer_list */

	/* waiters for input_buffer_list to go non-empty */
	wait_queue_head_t input_buffer_wq;

	/* data not yet read within current putfile_buffer_entry */
	struct putfile_active_buffer active_buf;

	/*
	 * <0 = failed, 0 = in-progress, >0 = successful;
	 * note that this must be set with req_list_lock, and if you set <0,
	 * it is your responsibility to also free up all of the other objects
	 * in this struct (like input_buffer_list, active_buf.parser_ctx)
	 * before releasing the lock
	 */
	int completion_status;
};

struct parahotplug_request {
	struct list_head list;
	int id;
	unsigned long expiration;
	struct controlvm_message msg;
};

static LIST_HEAD(parahotplug_request_list);
static DEFINE_SPINLOCK(parahotplug_request_list_lock);	/* lock for above */

/* info for /dev/visorchipset */
static dev_t major_dev = -1; /*< indicates major num for device */

/* prototypes for attributes */
static ssize_t toolaction_show(struct device *dev,
			       struct device_attribute *attr,
			       char *buf)
{
	u8 tool_action = 0;

	visorchannel_read(controlvm_channel,
			  offsetof(struct spar_controlvm_channel_protocol,
				   tool_action), &tool_action, sizeof(u8));
	return scnprintf(buf, PAGE_SIZE, "%u\n", tool_action);
}

static ssize_t toolaction_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	u8 tool_action;
	int ret;

	if (kstrtou8(buf, 10, &tool_action))
		return -EINVAL;

	ret = visorchannel_write
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  tool_action),
		 &tool_action, sizeof(u8));

	if (ret)
		return ret;
	return count;
}
static DEVICE_ATTR_RW(toolaction);

static ssize_t boottotool_show(struct device *dev,
			       struct device_attribute *attr, char *buf);
static ssize_t boottotool_store(struct device *dev,
				struct device_attribute *attr, const char *buf,
				size_t count);
static DEVICE_ATTR_RW(boottotool);

static ssize_t error_show(struct device *dev, struct device_attribute *attr,
			  char *buf);
static ssize_t error_store(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count);
static DEVICE_ATTR_RW(error);

static ssize_t textid_show(struct device *dev, struct device_attribute *attr,
			   char *buf);
static ssize_t textid_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count);
static DEVICE_ATTR_RW(textid);

static ssize_t remaining_steps_show(struct device *dev,
				    struct device_attribute *attr, char *buf);
static ssize_t remaining_steps_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count);
static DEVICE_ATTR_RW(remaining_steps);

static ssize_t devicedisabled_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count);
static DEVICE_ATTR_WO(devicedisabled);

static ssize_t deviceenabled_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count);
static DEVICE_ATTR_WO(deviceenabled);

static struct attribute *visorchipset_install_attrs[] = {
	&dev_attr_toolaction.attr,
	&dev_attr_boottotool.attr,
	&dev_attr_error.attr,
	&dev_attr_textid.attr,
	&dev_attr_remaining_steps.attr,
	NULL
};

static struct attribute_group visorchipset_install_group = {
	.name = "install",
	.attrs = visorchipset_install_attrs
};

static struct attribute *visorchipset_parahotplug_attrs[] = {
	&dev_attr_devicedisabled.attr,
	&dev_attr_deviceenabled.attr,
	NULL
};

static struct attribute_group visorchipset_parahotplug_group = {
	.name = "parahotplug",
	.attrs = visorchipset_parahotplug_attrs
};

static const struct attribute_group *visorchipset_dev_groups[] = {
	&visorchipset_install_group,
	&visorchipset_parahotplug_group,
	NULL
};

static void visorchipset_dev_release(struct device *dev)
{
}

/* /sys/devices/platform/visorchipset */
static struct platform_device visorchipset_platform_device = {
	.name = "visorchipset",
	.id = -1,
	.dev.groups = visorchipset_dev_groups,
	.dev.release = visorchipset_dev_release,
};

/* Function prototypes */
static void controlvm_respond_physdev_changestate(
		struct controlvm_message_header *msg_hdr, int response,
		struct spar_segment_state state);

static void parser_done(struct parser_context *ctx);

static struct parser_context *
parser_init_byte_stream(u64 addr, u32 bytes, bool local, bool *retry)
{
	int allocbytes = sizeof(struct parser_context) + bytes;
	struct parser_context *ctx;

	if (retry)
		*retry = false;

	/*
	 * alloc an 0 extra byte to ensure payload is
	 * '\0'-terminated
	 */
	allocbytes++;
	if ((controlvm_payload_bytes_buffered + bytes)
	    > MAX_CONTROLVM_PAYLOAD_BYTES) {
		if (retry)
			*retry = true;
		return NULL;
	}
	ctx = kzalloc(allocbytes, GFP_KERNEL | __GFP_NORETRY);
	if (!ctx) {
		if (retry)
			*retry = true;
		return NULL;
	}

	ctx->allocbytes = allocbytes;
	ctx->param_bytes = bytes;
	ctx->curr = NULL;
	ctx->bytes_remaining = 0;
	ctx->byte_stream = false;
	if (local) {
		void *p;

		if (addr > virt_to_phys(high_memory - 1))
			goto err_finish_ctx;
		p = __va((unsigned long)(addr));
		memcpy(ctx->data, p, bytes);
	} else {
		void *mapping = memremap(addr, bytes, MEMREMAP_WB);

		if (!mapping)
			goto err_finish_ctx;
		memcpy(ctx->data, mapping, bytes);
		memunmap(mapping);
	}

	ctx->byte_stream = true;
	controlvm_payload_bytes_buffered += ctx->param_bytes;

	return ctx;

err_finish_ctx:
	parser_done(ctx);
	return NULL;
}

static uuid_le
parser_id_get(struct parser_context *ctx)
{
	struct spar_controlvm_parameters_header *phdr = NULL;

	if (!ctx)
		return NULL_UUID_LE;
	phdr = (struct spar_controlvm_parameters_header *)(ctx->data);
	return phdr->id;
}

/*
 * Describes the state from the perspective of which controlvm messages have
 * been received for a bus or device.
 */

enum PARSER_WHICH_STRING {
	PARSERSTRING_INITIATOR,
	PARSERSTRING_TARGET,
	PARSERSTRING_CONNECTION,
	PARSERSTRING_NAME, /* TODO: only PARSERSTRING_NAME is used ? */
};

static void
parser_param_start(struct parser_context *ctx,
		   enum PARSER_WHICH_STRING which_string)
{
	struct spar_controlvm_parameters_header *phdr = NULL;

	if (!ctx)
		return;

	phdr = (struct spar_controlvm_parameters_header *)(ctx->data);
	switch (which_string) {
	case PARSERSTRING_INITIATOR:
		ctx->curr = ctx->data + phdr->initiator_offset;
		ctx->bytes_remaining = phdr->initiator_length;
		break;
	case PARSERSTRING_TARGET:
		ctx->curr = ctx->data + phdr->target_offset;
		ctx->bytes_remaining = phdr->target_length;
		break;
	case PARSERSTRING_CONNECTION:
		ctx->curr = ctx->data + phdr->connection_offset;
		ctx->bytes_remaining = phdr->connection_length;
		break;
	case PARSERSTRING_NAME:
		ctx->curr = ctx->data + phdr->name_offset;
		ctx->bytes_remaining = phdr->name_length;
		break;
	default:
		break;
	}
}

static void parser_done(struct parser_context *ctx)
{
	if (!ctx)
		return;
	controlvm_payload_bytes_buffered -= ctx->param_bytes;
	kfree(ctx);
}

static void *
parser_string_get(struct parser_context *ctx)
{
	u8 *pscan;
	unsigned long nscan;
	int value_length = -1;
	void *value = NULL;
	int i;

	if (!ctx)
		return NULL;
	pscan = ctx->curr;
	nscan = ctx->bytes_remaining;
	if (nscan == 0)
		return NULL;
	if (!pscan)
		return NULL;
	for (i = 0, value_length = -1; i < nscan; i++)
		if (pscan[i] == '\0') {
			value_length = i;
			break;
		}
	if (value_length < 0)	/* '\0' was not included in the length */
		value_length = nscan;
	value = kmalloc(value_length + 1, GFP_KERNEL | __GFP_NORETRY);
	if (!value)
		return NULL;
	if (value_length > 0)
		memcpy(value, pscan, value_length);
	((u8 *)(value))[value_length] = '\0';
	return value;
}

static ssize_t boottotool_show(struct device *dev,
			       struct device_attribute *attr,
			       char *buf)
{
	struct efi_spar_indication efi_spar_indication;

	visorchannel_read(controlvm_channel,
			  offsetof(struct spar_controlvm_channel_protocol,
				   efi_spar_ind), &efi_spar_indication,
			  sizeof(struct efi_spar_indication));
	return scnprintf(buf, PAGE_SIZE, "%u\n",
			 efi_spar_indication.boot_to_tool);
}

static ssize_t boottotool_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	int val, ret;
	struct efi_spar_indication efi_spar_indication;

	if (kstrtoint(buf, 10, &val))
		return -EINVAL;

	efi_spar_indication.boot_to_tool = val;
	ret = visorchannel_write
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  efi_spar_ind), &(efi_spar_indication),
		 sizeof(struct efi_spar_indication));

	if (ret)
		return ret;
	return count;
}

static ssize_t error_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	u32 error = 0;

	visorchannel_read(controlvm_channel,
			  offsetof(struct spar_controlvm_channel_protocol,
				   installation_error),
			  &error, sizeof(u32));
	return scnprintf(buf, PAGE_SIZE, "%i\n", error);
}

static ssize_t error_store(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	u32 error;
	int ret;

	if (kstrtou32(buf, 10, &error))
		return -EINVAL;

	ret = visorchannel_write
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_error),
		 &error, sizeof(u32));
	if (ret)
		return ret;
	return count;
}

static ssize_t textid_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	u32 text_id = 0;

	visorchannel_read
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_text_id),
		 &text_id, sizeof(u32));
	return scnprintf(buf, PAGE_SIZE, "%i\n", text_id);
}

static ssize_t textid_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	u32 text_id;
	int ret;

	if (kstrtou32(buf, 10, &text_id))
		return -EINVAL;

	ret = visorchannel_write
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_text_id),
		 &text_id, sizeof(u32));
	if (ret)
		return ret;
	return count;
}

static ssize_t remaining_steps_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	u16 remaining_steps = 0;

	visorchannel_read(controlvm_channel,
			  offsetof(struct spar_controlvm_channel_protocol,
				   installation_remaining_steps),
			  &remaining_steps, sizeof(u16));
	return scnprintf(buf, PAGE_SIZE, "%hu\n", remaining_steps);
}

static ssize_t remaining_steps_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	u16 remaining_steps;
	int ret;

	if (kstrtou16(buf, 10, &remaining_steps))
		return -EINVAL;

	ret = visorchannel_write
		(controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_remaining_steps),
		 &remaining_steps, sizeof(u16));
	if (ret)
		return ret;
	return count;
}

struct visor_busdev {
	u32 bus_no;
	u32 dev_no;
};

static int match_visorbus_dev_by_id(struct device *dev, void *data)
{
	struct visor_device *vdev = to_visor_device(dev);
	struct visor_busdev *id = data;
	u32 bus_no = id->bus_no;
	u32 dev_no = id->dev_no;

	if ((vdev->chipset_bus_no == bus_no) &&
	    (vdev->chipset_dev_no == dev_no))
		return 1;

	return 0;
}

struct visor_device *visorbus_get_device_by_id(u32 bus_no, u32 dev_no,
					       struct visor_device *from)
{
	struct device *dev;
	struct device *dev_start = NULL;
	struct visor_device *vdev = NULL;
	struct visor_busdev id = {
			.bus_no = bus_no,
			.dev_no = dev_no
		};

	if (from)
		dev_start = &from->device;
	dev = bus_find_device(&visorbus_type, dev_start, (void *)&id,
			      match_visorbus_dev_by_id);
	if (dev)
		vdev = to_visor_device(dev);
	return vdev;
}

static void
controlvm_init_response(struct controlvm_message *msg,
			struct controlvm_message_header *msg_hdr, int response)
{
	memset(msg, 0, sizeof(struct controlvm_message));
	memcpy(&msg->hdr, msg_hdr, sizeof(struct controlvm_message_header));
	msg->hdr.payload_bytes = 0;
	msg->hdr.payload_vm_offset = 0;
	msg->hdr.payload_max_bytes = 0;
	if (response < 0) {
		msg->hdr.flags.failed = 1;
		msg->hdr.completion_status = (u32)(-response);
	}
}

static void
controlvm_respond_chipset_init(struct controlvm_message_header *msg_hdr,
			       int response,
			       enum ultra_chipset_feature features)
{
	struct controlvm_message outmsg;

	controlvm_init_response(&outmsg, msg_hdr, response);
	outmsg.cmd.init_chipset.features = features;
	if (!visorchannel_signalinsert(controlvm_channel,
				       CONTROLVM_QUEUE_REQUEST, &outmsg)) {
		return;
	}
}

static void
chipset_init(struct controlvm_message *inmsg)
{
	static int chipset_inited;
	enum ultra_chipset_feature features = 0;
	int rc = CONTROLVM_RESP_SUCCESS;

	POSTCODE_LINUX_2(CHIPSET_INIT_ENTRY_PC, POSTCODE_SEVERITY_INFO);
	if (chipset_inited) {
		rc = -CONTROLVM_RESP_ERROR_ALREADY_DONE;
		goto out_respond;
	}
	chipset_inited = 1;
	POSTCODE_LINUX_2(CHIPSET_INIT_EXIT_PC, POSTCODE_SEVERITY_INFO);

	/*
	 * Set features to indicate we support parahotplug (if Command
	 * also supports it).
	 */
	features =
	    inmsg->cmd.init_chipset.
	    features & ULTRA_CHIPSET_FEATURE_PARA_HOTPLUG;

	/*
	 * Set the "reply" bit so Command knows this is a
	 * features-aware driver.
	 */
	features |= ULTRA_CHIPSET_FEATURE_REPLY;

out_respond:
	if (inmsg->hdr.flags.response_expected)
		controlvm_respond_chipset_init(&inmsg->hdr, rc, features);
}

static void
controlvm_respond(struct controlvm_message_header *msg_hdr, int response)
{
	struct controlvm_message outmsg;

	controlvm_init_response(&outmsg, msg_hdr, response);
	if (outmsg.hdr.flags.test_message == 1)
		return;

	if (!visorchannel_signalinsert(controlvm_channel,
				       CONTROLVM_QUEUE_REQUEST, &outmsg)) {
		return;
	}
}

static void controlvm_respond_physdev_changestate(
		struct controlvm_message_header *msg_hdr, int response,
		struct spar_segment_state state)
{
	struct controlvm_message outmsg;

	controlvm_init_response(&outmsg, msg_hdr, response);
	outmsg.cmd.device_change_state.state = state;
	outmsg.cmd.device_change_state.flags.phys_device = 1;
	if (!visorchannel_signalinsert(controlvm_channel,
				       CONTROLVM_QUEUE_REQUEST, &outmsg)) {
		return;
	}
}

enum crash_obj_type {
	CRASH_DEV,
	CRASH_BUS,
};

static void
save_crash_message(struct controlvm_message *msg, enum crash_obj_type typ)
{
	u32 local_crash_msg_offset;
	u16 local_crash_msg_count;

	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_count),
			      &local_crash_msg_count, sizeof(u16)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	if (local_crash_msg_count != CONTROLVM_CRASHMSG_MAX) {
		POSTCODE_LINUX_3(CRASH_DEV_COUNT_FAILURE_PC,
				 local_crash_msg_count,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_offset),
			      &local_crash_msg_offset, sizeof(u32)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	if (typ == CRASH_BUS) {
		if (visorchannel_write(controlvm_channel,
				       local_crash_msg_offset,
				       msg,
				       sizeof(struct controlvm_message)) < 0) {
			POSTCODE_LINUX_2(SAVE_MSG_BUS_FAILURE_PC,
					 POSTCODE_SEVERITY_ERR);
			return;
		}
	} else {
		local_crash_msg_offset += sizeof(struct controlvm_message);
		if (visorchannel_write(controlvm_channel,
				       local_crash_msg_offset,
				       msg,
				       sizeof(struct controlvm_message)) < 0) {
			POSTCODE_LINUX_2(SAVE_MSG_DEV_FAILURE_PC,
					 POSTCODE_SEVERITY_ERR);
			return;
		}
	}
}

static void
bus_responder(enum controlvm_id cmd_id,
	      struct controlvm_message_header *pending_msg_hdr,
	      int response)
{
	if (!pending_msg_hdr)
		return;		/* no controlvm response needed */

	if (pending_msg_hdr->id != (u32)cmd_id)
		return;

	controlvm_respond(pending_msg_hdr, response);
}

static void
device_changestate_responder(enum controlvm_id cmd_id,
			     struct visor_device *p, int response,
			     struct spar_segment_state response_state)
{
	struct controlvm_message outmsg;
	u32 bus_no = p->chipset_bus_no;
	u32 dev_no = p->chipset_dev_no;

	if (!p->pending_msg_hdr)
		return;		/* no controlvm response needed */
	if (p->pending_msg_hdr->id != cmd_id)
		return;

	controlvm_init_response(&outmsg, p->pending_msg_hdr, response);

	outmsg.cmd.device_change_state.bus_no = bus_no;
	outmsg.cmd.device_change_state.dev_no = dev_no;
	outmsg.cmd.device_change_state.state = response_state;

	if (!visorchannel_signalinsert(controlvm_channel,
				       CONTROLVM_QUEUE_REQUEST, &outmsg))
		return;
}

static void
device_responder(enum controlvm_id cmd_id,
		 struct controlvm_message_header *pending_msg_hdr,
		 int response)
{
	if (!pending_msg_hdr)
		return;		/* no controlvm response needed */

	if (pending_msg_hdr->id != (u32)cmd_id)
		return;

	controlvm_respond(pending_msg_hdr, response);
}

static void
bus_epilog(struct visor_device *bus_info,
	   u32 cmd, struct controlvm_message_header *msg_hdr,
	   int response, bool need_response)
{
	struct controlvm_message_header *pmsg_hdr = NULL;

	if (!bus_info) {
		/*
		 * relying on a valid passed in response code
		 * be lazy and re-use msg_hdr for this failure, is this ok??
		 */
		pmsg_hdr = msg_hdr;
		goto out_respond;
	}

	if (bus_info->pending_msg_hdr) {
		/* only non-NULL if dev is still waiting on a response */
		response = -CONTROLVM_RESP_ERROR_MESSAGE_ID_INVALID_FOR_CLIENT;
		pmsg_hdr = bus_info->pending_msg_hdr;
		goto out_respond;
	}

	if (need_response) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			POSTCODE_LINUX_4(MALLOC_FAILURE_PC, cmd,
					 bus_info->chipset_bus_no,
					 POSTCODE_SEVERITY_ERR);
			return;
		}

		memcpy(pmsg_hdr, msg_hdr,
		       sizeof(struct controlvm_message_header));
		bus_info->pending_msg_hdr = pmsg_hdr;
	}

	if (response == CONTROLVM_RESP_SUCCESS) {
		switch (cmd) {
		case CONTROLVM_BUS_CREATE:
			chipset_bus_create(bus_info);
			break;
		case CONTROLVM_BUS_DESTROY:
			chipset_bus_destroy(bus_info);
			break;
		}
	}

out_respond:
	bus_responder(cmd, pmsg_hdr, response);
}

static void
device_epilog(struct visor_device *dev_info,
	      struct spar_segment_state state, u32 cmd,
	      struct controlvm_message_header *msg_hdr, int response,
	      bool need_response, bool for_visorbus)
{
	struct controlvm_message_header *pmsg_hdr = NULL;

	if (!dev_info) {
		/*
		 * relying on a valid passed in response code
		 * be lazy and re-use msg_hdr for this failure, is this ok??
		 */
		pmsg_hdr = msg_hdr;
		goto out_respond;
	}

	if (dev_info->pending_msg_hdr) {
		/* only non-NULL if dev is still waiting on a response */
		response = -CONTROLVM_RESP_ERROR_MESSAGE_ID_INVALID_FOR_CLIENT;
		pmsg_hdr = dev_info->pending_msg_hdr;
		goto out_respond;
	}

	if (need_response) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			response = -CONTROLVM_RESP_ERROR_KMALLOC_FAILED;
			goto out_respond;
		}

		memcpy(pmsg_hdr, msg_hdr,
		       sizeof(struct controlvm_message_header));
		dev_info->pending_msg_hdr = pmsg_hdr;
	}

	if (response >= 0) {
		switch (cmd) {
		case CONTROLVM_DEVICE_CREATE:
			chipset_device_create(dev_info);
			break;
		case CONTROLVM_DEVICE_CHANGESTATE:
			/* ServerReady / ServerRunning / SegmentStateRunning */
			if (state.alive == segment_state_running.alive &&
			    state.operating ==
				segment_state_running.operating) {
				chipset_device_resume(dev_info);
			}
			/* ServerNotReady / ServerLost / SegmentStateStandby */
			else if (state.alive == segment_state_standby.alive &&
				 state.operating ==
				 segment_state_standby.operating) {
				/*
				 * technically this is standby case
				 * where server is lost
				 */
				chipset_device_pause(dev_info);
			}
			break;
		case CONTROLVM_DEVICE_DESTROY:
			chipset_device_destroy(dev_info);
			break;
		}
	}

out_respond:
	device_responder(cmd, pmsg_hdr, response);
}

static void
bus_create(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no = cmd->create_bus.bus_no;
	int rc = CONTROLVM_RESP_SUCCESS;
	struct visor_device *bus_info;
	struct visorchannel *visorchannel;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (bus_info && (bus_info->state.created == 1)) {
		POSTCODE_LINUX_3(BUS_CREATE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_ALREADY_DONE;
		goto out_bus_epilog;
	}
	bus_info = kzalloc(sizeof(*bus_info), GFP_KERNEL);
	if (!bus_info) {
		POSTCODE_LINUX_3(BUS_CREATE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_KMALLOC_FAILED;
		goto out_bus_epilog;
	}

	INIT_LIST_HEAD(&bus_info->list_all);
	bus_info->chipset_bus_no = bus_no;
	bus_info->chipset_dev_no = BUS_ROOT_DEVICE;

	POSTCODE_LINUX_3(BUS_CREATE_ENTRY_PC, bus_no, POSTCODE_SEVERITY_INFO);

	visorchannel = visorchannel_create(cmd->create_bus.channel_addr,
					   cmd->create_bus.channel_bytes,
					   GFP_KERNEL,
					   cmd->create_bus.bus_data_type_uuid);

	if (!visorchannel) {
		POSTCODE_LINUX_3(BUS_CREATE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_KMALLOC_FAILED;
		kfree(bus_info);
		bus_info = NULL;
		goto out_bus_epilog;
	}
	bus_info->visorchannel = visorchannel;
	if (uuid_le_cmp(cmd->create_bus.bus_inst_uuid, spar_siovm_uuid) == 0)
		save_crash_message(inmsg, CRASH_BUS);

	POSTCODE_LINUX_3(BUS_CREATE_EXIT_PC, bus_no, POSTCODE_SEVERITY_INFO);

out_bus_epilog:
	bus_epilog(bus_info, CONTROLVM_BUS_CREATE, &inmsg->hdr,
		   rc, inmsg->hdr.flags.response_expected == 1);
}

static void
bus_destroy(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no = cmd->destroy_bus.bus_no;
	struct visor_device *bus_info;
	int rc = CONTROLVM_RESP_SUCCESS;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info)
		rc = -CONTROLVM_RESP_ERROR_BUS_INVALID;
	else if (bus_info->state.created == 0)
		rc = -CONTROLVM_RESP_ERROR_ALREADY_DONE;

	bus_epilog(bus_info, CONTROLVM_BUS_DESTROY, &inmsg->hdr,
		   rc, inmsg->hdr.flags.response_expected == 1);

	/* bus_info is freed as part of the busdevice_release function */
}

static void
bus_configure(struct controlvm_message *inmsg,
	      struct parser_context *parser_ctx)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no;
	struct visor_device *bus_info;
	int rc = CONTROLVM_RESP_SUCCESS;

	bus_no = cmd->configure_bus.bus_no;
	POSTCODE_LINUX_3(BUS_CONFIGURE_ENTRY_PC, bus_no,
			 POSTCODE_SEVERITY_INFO);

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info) {
		POSTCODE_LINUX_3(BUS_CONFIGURE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_BUS_INVALID;
	} else if (bus_info->state.created == 0) {
		POSTCODE_LINUX_3(BUS_CONFIGURE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_BUS_INVALID;
	} else if (bus_info->pending_msg_hdr) {
		POSTCODE_LINUX_3(BUS_CONFIGURE_FAILURE_PC, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_MESSAGE_ID_INVALID_FOR_CLIENT;
	} else {
		visorchannel_set_clientpartition
			(bus_info->visorchannel,
			 cmd->configure_bus.guest_handle);
		bus_info->partition_uuid = parser_id_get(parser_ctx);
		parser_param_start(parser_ctx, PARSERSTRING_NAME);
		bus_info->name = parser_string_get(parser_ctx);

		POSTCODE_LINUX_3(BUS_CONFIGURE_EXIT_PC, bus_no,
				 POSTCODE_SEVERITY_INFO);
	}
	bus_epilog(bus_info, CONTROLVM_BUS_CONFIGURE, &inmsg->hdr,
		   rc, inmsg->hdr.flags.response_expected == 1);
}

static void
my_device_create(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no = cmd->create_device.bus_no;
	u32 dev_no = cmd->create_device.dev_no;
	struct visor_device *dev_info = NULL;
	struct visor_device *bus_info;
	struct visorchannel *visorchannel;
	int rc = CONTROLVM_RESP_SUCCESS;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info) {
		POSTCODE_LINUX_4(DEVICE_CREATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_BUS_INVALID;
		goto out_respond;
	}

	if (bus_info->state.created == 0) {
		POSTCODE_LINUX_4(DEVICE_CREATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_BUS_INVALID;
		goto out_respond;
	}

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (dev_info && (dev_info->state.created == 1)) {
		POSTCODE_LINUX_4(DEVICE_CREATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_ALREADY_DONE;
		goto out_respond;
	}

	dev_info = kzalloc(sizeof(*dev_info), GFP_KERNEL);
	if (!dev_info) {
		POSTCODE_LINUX_4(DEVICE_CREATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_KMALLOC_FAILED;
		goto out_respond;
	}

	dev_info->chipset_bus_no = bus_no;
	dev_info->chipset_dev_no = dev_no;
	dev_info->inst = cmd->create_device.dev_inst_uuid;

	/* not sure where the best place to set the 'parent' */
	dev_info->device.parent = &bus_info->device;

	POSTCODE_LINUX_4(DEVICE_CREATE_ENTRY_PC, dev_no, bus_no,
			 POSTCODE_SEVERITY_INFO);

	visorchannel =
	       visorchannel_create_with_lock(cmd->create_device.channel_addr,
					     cmd->create_device.channel_bytes,
					     GFP_KERNEL,
					     cmd->create_device.data_type_uuid);

	if (!visorchannel) {
		POSTCODE_LINUX_4(DEVICE_CREATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_KMALLOC_FAILED;
		kfree(dev_info);
		dev_info = NULL;
		goto out_respond;
	}
	dev_info->visorchannel = visorchannel;
	dev_info->channel_type_guid = cmd->create_device.data_type_uuid;
	if (uuid_le_cmp(cmd->create_device.data_type_uuid,
			spar_vhba_channel_protocol_uuid) == 0)
		save_crash_message(inmsg, CRASH_DEV);

	POSTCODE_LINUX_4(DEVICE_CREATE_EXIT_PC, dev_no, bus_no,
			 POSTCODE_SEVERITY_INFO);
out_respond:
	device_epilog(dev_info, segment_state_running,
		      CONTROLVM_DEVICE_CREATE, &inmsg->hdr, rc,
		      inmsg->hdr.flags.response_expected == 1, 1);
}

static void
my_device_changestate(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no = cmd->device_change_state.bus_no;
	u32 dev_no = cmd->device_change_state.dev_no;
	struct spar_segment_state state = cmd->device_change_state.state;
	struct visor_device *dev_info;
	int rc = CONTROLVM_RESP_SUCCESS;

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (!dev_info) {
		POSTCODE_LINUX_4(DEVICE_CHANGESTATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_DEVICE_INVALID;
	} else if (dev_info->state.created == 0) {
		POSTCODE_LINUX_4(DEVICE_CHANGESTATE_FAILURE_PC, dev_no, bus_no,
				 POSTCODE_SEVERITY_ERR);
		rc = -CONTROLVM_RESP_ERROR_DEVICE_INVALID;
	}
	if ((rc >= CONTROLVM_RESP_SUCCESS) && dev_info)
		device_epilog(dev_info, state,
			      CONTROLVM_DEVICE_CHANGESTATE, &inmsg->hdr, rc,
			      inmsg->hdr.flags.response_expected == 1, 1);
}

static void
my_device_destroy(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	u32 bus_no = cmd->destroy_device.bus_no;
	u32 dev_no = cmd->destroy_device.dev_no;
	struct visor_device *dev_info;
	int rc = CONTROLVM_RESP_SUCCESS;

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (!dev_info)
		rc = -CONTROLVM_RESP_ERROR_DEVICE_INVALID;
	else if (dev_info->state.created == 0)
		rc = -CONTROLVM_RESP_ERROR_ALREADY_DONE;

	if ((rc >= CONTROLVM_RESP_SUCCESS) && dev_info)
		device_epilog(dev_info, segment_state_running,
			      CONTROLVM_DEVICE_DESTROY, &inmsg->hdr, rc,
			      inmsg->hdr.flags.response_expected == 1, 1);
}

/**
 * initialize_controlvm_payload_info() - init controlvm_payload_info struct
 * @phys_addr: the physical address of controlvm channel
 * @offset:    the offset to payload
 * @bytes:     the size of the payload in bytes
 * @info:      the returning valid struct
 *
 * When provided with the physical address of the controlvm channel
 * (phys_addr), the offset to the payload area we need to manage
 * (offset), and the size of this payload area (bytes), fills in the
 * controlvm_payload_info struct.
 *
 * Return: CONTROLVM_RESP_SUCCESS for success or a negative for failure
 */
static int
initialize_controlvm_payload_info(u64 phys_addr, u64 offset, u32 bytes,
				  struct visor_controlvm_payload_info *info)
{
	u8 *payload = NULL;

	if (!info)
		return -CONTROLVM_RESP_ERROR_PAYLOAD_INVALID;

	memset(info, 0, sizeof(struct visor_controlvm_payload_info));
	if ((offset == 0) || (bytes == 0))
		return -CONTROLVM_RESP_ERROR_PAYLOAD_INVALID;

	payload = memremap(phys_addr + offset, bytes, MEMREMAP_WB);
	if (!payload)
		return -CONTROLVM_RESP_ERROR_IOREMAP_FAILED;

	info->offset = offset;
	info->bytes = bytes;
	info->ptr = payload;

	return CONTROLVM_RESP_SUCCESS;
}

static void
destroy_controlvm_payload_info(struct visor_controlvm_payload_info *info)
{
	if (info->ptr) {
		memunmap(info->ptr);
		info->ptr = NULL;
	}
	memset(info, 0, sizeof(struct visor_controlvm_payload_info));
}

static void
initialize_controlvm_payload(void)
{
	u64 phys_addr = visorchannel_get_physaddr(controlvm_channel);
	u64 payload_offset = 0;
	u32 payload_bytes = 0;

	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       request_payload_offset),
			      &payload_offset, sizeof(payload_offset)) < 0) {
		POSTCODE_LINUX_2(CONTROLVM_INIT_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}
	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       request_payload_bytes),
			      &payload_bytes, sizeof(payload_bytes)) < 0) {
		POSTCODE_LINUX_2(CONTROLVM_INIT_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}
	initialize_controlvm_payload_info(phys_addr,
					  payload_offset, payload_bytes,
					  &controlvm_payload_info);
}

/**
 * visorchipset_chipset_ready() - sends chipset_ready action
 *
 * Send ACTION=online for DEVPATH=/sys/devices/platform/visorchipset.
 *
 * Return: CONTROLVM_RESP_SUCCESS
 */
static int
visorchipset_chipset_ready(void)
{
	kobject_uevent(&visorchipset_platform_device.dev.kobj, KOBJ_ONLINE);
	return CONTROLVM_RESP_SUCCESS;
}

static int
visorchipset_chipset_selftest(void)
{
	char env_selftest[20];
	char *envp[] = { env_selftest, NULL };

	sprintf(env_selftest, "SPARSP_SELFTEST=%d", 1);
	kobject_uevent_env(&visorchipset_platform_device.dev.kobj, KOBJ_CHANGE,
			   envp);
	return CONTROLVM_RESP_SUCCESS;
}

/**
 * visorchipset_chipset_notready() - sends chipset_notready action
 *
 * Send ACTION=offline for DEVPATH=/sys/devices/platform/visorchipset.
 *
 * Return: CONTROLVM_RESP_SUCCESS
 */
static int
visorchipset_chipset_notready(void)
{
	kobject_uevent(&visorchipset_platform_device.dev.kobj, KOBJ_OFFLINE);
	return CONTROLVM_RESP_SUCCESS;
}

static void
chipset_ready(struct controlvm_message_header *msg_hdr)
{
	int rc = visorchipset_chipset_ready();

	if (rc != CONTROLVM_RESP_SUCCESS)
		rc = -rc;
	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, rc);
}

static void
chipset_selftest(struct controlvm_message_header *msg_hdr)
{
	int rc = visorchipset_chipset_selftest();

	if (rc != CONTROLVM_RESP_SUCCESS)
		rc = -rc;
	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, rc);
}

static void
chipset_notready(struct controlvm_message_header *msg_hdr)
{
	int rc = visorchipset_chipset_notready();

	if (rc != CONTROLVM_RESP_SUCCESS)
		rc = -rc;
	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, rc);
}

/*
 * The general parahotplug flow works as follows. The visorchipset
 * driver receives a DEVICE_CHANGESTATE message from Command
 * specifying a physical device to enable or disable. The CONTROLVM
 * message handler calls parahotplug_process_message, which then adds
 * the message to a global list and kicks off a udev event which
 * causes a user level script to enable or disable the specified
 * device. The udev script then writes to
 * /proc/visorchipset/parahotplug, which causes parahotplug_proc_write
 * to get called, at which point the appropriate CONTROLVM message is
 * retrieved from the list and responded to.
 */

#define PARAHOTPLUG_TIMEOUT_MS 2000

/**
 * parahotplug_next_id() - generate unique int to match an outstanding CONTROLVM
 *                         message with a udev script /proc response
 *
 * Return: a unique integer value
 */
static int
parahotplug_next_id(void)
{
	static atomic_t id = ATOMIC_INIT(0);

	return atomic_inc_return(&id);
}

/**
 * parahotplug_next_expiration() - returns the time (in jiffies) when a
 *                                 CONTROLVM message on the list should expire
 *                                 -- PARAHOTPLUG_TIMEOUT_MS in the future
 *
 * Return: expected expiration time (in jiffies)
 */
static unsigned long
parahotplug_next_expiration(void)
{
	return jiffies + msecs_to_jiffies(PARAHOTPLUG_TIMEOUT_MS);
}

/**
 * parahotplug_request_create() - create a parahotplug_request, which is
 *                                basically a wrapper for a CONTROLVM_MESSAGE
 *                                that we can stick on a list
 * @msg: the message to insert in the request
 *
 * Return: the request containing the provided message
 */
static struct parahotplug_request *
parahotplug_request_create(struct controlvm_message *msg)
{
	struct parahotplug_request *req;

	req = kmalloc(sizeof(*req), GFP_KERNEL | __GFP_NORETRY);
	if (!req)
		return NULL;

	req->id = parahotplug_next_id();
	req->expiration = parahotplug_next_expiration();
	req->msg = *msg;

	return req;
}

/**
 * parahotplug_request_destroy() - free a parahotplug_request
 * @req: the request to deallocate
 */
static void
parahotplug_request_destroy(struct parahotplug_request *req)
{
	kfree(req);
}

/**
 * parahotplug_request_kickoff() - initiate parahotplug request
 * @req: the request to initiate
 *
 * Cause uevent to run the user level script to do the disable/enable specified
 * in the parahotplug_request.
 */
static void
parahotplug_request_kickoff(struct parahotplug_request *req)
{
	struct controlvm_message_packet *cmd = &req->msg.cmd;
	char env_cmd[40], env_id[40], env_state[40], env_bus[40], env_dev[40],
	    env_func[40];
	char *envp[] = {
		env_cmd, env_id, env_state, env_bus, env_dev, env_func, NULL
	};

	sprintf(env_cmd, "SPAR_PARAHOTPLUG=1");
	sprintf(env_id, "SPAR_PARAHOTPLUG_ID=%d", req->id);
	sprintf(env_state, "SPAR_PARAHOTPLUG_STATE=%d",
		cmd->device_change_state.state.active);
	sprintf(env_bus, "SPAR_PARAHOTPLUG_BUS=%d",
		cmd->device_change_state.bus_no);
	sprintf(env_dev, "SPAR_PARAHOTPLUG_DEVICE=%d",
		cmd->device_change_state.dev_no >> 3);
	sprintf(env_func, "SPAR_PARAHOTPLUG_FUNCTION=%d",
		cmd->device_change_state.dev_no & 0x7);

	kobject_uevent_env(&visorchipset_platform_device.dev.kobj, KOBJ_CHANGE,
			   envp);
}

/**
 * parahotplug_request_complete() - mark request as complete
 * @id:     the id of the request
 * @active: indicates whether the request is assigned to active partition
 *
 * Called from the /proc handler, which means the user script has
 * finished the enable/disable. Find the matching identifier, and
 * respond to the CONTROLVM message with success.
 *
 * Return: 0 on success or -EINVAL on failure
 */
static int
parahotplug_request_complete(int id, u16 active)
{
	struct list_head *pos;
	struct list_head *tmp;

	spin_lock(&parahotplug_request_list_lock);

	/* Look for a request matching "id". */
	list_for_each_safe(pos, tmp, &parahotplug_request_list) {
		struct parahotplug_request *req =
		    list_entry(pos, struct parahotplug_request, list);
		if (req->id == id) {
			/*
			 * Found a match. Remove it from the list and
			 * respond.
			 */
			list_del(pos);
			spin_unlock(&parahotplug_request_list_lock);
			req->msg.cmd.device_change_state.state.active = active;
			if (req->msg.hdr.flags.response_expected)
				controlvm_respond_physdev_changestate(
					&req->msg.hdr, CONTROLVM_RESP_SUCCESS,
					req->msg.cmd.device_change_state.state);
			parahotplug_request_destroy(req);
			return 0;
		}
	}

	spin_unlock(&parahotplug_request_list_lock);
	return -EINVAL;
}

/**
 * parahotplug_process_message() - enables or disables a PCI device by kicking
 *                                 off a udev script
 * @inmsg: the message indicating whether to enable or disable
 */
static void
parahotplug_process_message(struct controlvm_message *inmsg)
{
	struct parahotplug_request *req;

	req = parahotplug_request_create(inmsg);

	if (!req)
		return;

	if (inmsg->cmd.device_change_state.state.active) {
		/*
		 * For enable messages, just respond with success
		 * right away. This is a bit of a hack, but there are
		 * issues with the early enable messages we get (with
		 * either the udev script not detecting that the device
		 * is up, or not getting called at all). Fortunately
		 * the messages that get lost don't matter anyway, as
		 *
		 * devices are automatically enabled at
		 * initialization.
		*/
		parahotplug_request_kickoff(req);
		controlvm_respond_physdev_changestate
			(&inmsg->hdr,
			 CONTROLVM_RESP_SUCCESS,
			 inmsg->cmd.device_change_state.state);
		parahotplug_request_destroy(req);
	} else {
		/*
		 * For disable messages, add the request to the
		 * request list before kicking off the udev script. It
		 * won't get responded to until the script has
		 * indicated it's done.
		 */
		spin_lock(&parahotplug_request_list_lock);
		list_add_tail(&req->list, &parahotplug_request_list);
		spin_unlock(&parahotplug_request_list_lock);

		parahotplug_request_kickoff(req);
	}
}

static inline unsigned int
issue_vmcall_io_controlvm_addr(u64 *control_addr, u32 *control_bytes)
{
	struct vmcall_io_controlvm_addr_params params;
	int result = VMCALL_SUCCESS;
	u64 physaddr;

	physaddr = virt_to_phys(&params);
	ISSUE_IO_VMCALL(VMCALL_IO_CONTROLVM_ADDR, physaddr, result);
	if (VMCALL_SUCCESSFUL(result)) {
		*control_addr = params.address;
		*control_bytes = params.channel_bytes;
	}
	return result;
}

static u64 controlvm_get_channel_address(void)
{
	u64 addr = 0;
	u32 size = 0;

	if (!VMCALL_SUCCESSFUL(issue_vmcall_io_controlvm_addr(&addr, &size)))
		return 0;

	return addr;
}

static void
setup_crash_devices_work_queue(struct work_struct *work)
{
	struct controlvm_message local_crash_bus_msg;
	struct controlvm_message local_crash_dev_msg;
	struct controlvm_message msg;
	u32 local_crash_msg_offset;
	u16 local_crash_msg_count;

	POSTCODE_LINUX_2(CRASH_DEV_ENTRY_PC, POSTCODE_SEVERITY_INFO);

	/* send init chipset msg */
	msg.hdr.id = CONTROLVM_CHIPSET_INIT;
	msg.cmd.init_chipset.bus_count = 23;
	msg.cmd.init_chipset.switch_count = 0;

	chipset_init(&msg);

	/* get saved message count */
	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_count),
			      &local_crash_msg_count, sizeof(u16)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	if (local_crash_msg_count != CONTROLVM_CRASHMSG_MAX) {
		POSTCODE_LINUX_3(CRASH_DEV_COUNT_FAILURE_PC,
				 local_crash_msg_count,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	/* get saved crash message offset */
	if (visorchannel_read(controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_offset),
			      &local_crash_msg_offset, sizeof(u32)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	/* read create device message for storage bus offset */
	if (visorchannel_read(controlvm_channel,
			      local_crash_msg_offset,
			      &local_crash_bus_msg,
			      sizeof(struct controlvm_message)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_RD_BUS_FAIULRE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	/* read create device message for storage device */
	if (visorchannel_read(controlvm_channel,
			      local_crash_msg_offset +
			      sizeof(struct controlvm_message),
			      &local_crash_dev_msg,
			      sizeof(struct controlvm_message)) < 0) {
		POSTCODE_LINUX_2(CRASH_DEV_RD_DEV_FAIULRE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	/* reuse IOVM create bus message */
	if (local_crash_bus_msg.cmd.create_bus.channel_addr) {
		bus_create(&local_crash_bus_msg);
	} else {
		POSTCODE_LINUX_2(CRASH_DEV_BUS_NULL_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}

	/* reuse create device message for storage device */
	if (local_crash_dev_msg.cmd.create_device.channel_addr) {
		my_device_create(&local_crash_dev_msg);
	} else {
		POSTCODE_LINUX_2(CRASH_DEV_DEV_NULL_FAILURE_PC,
				 POSTCODE_SEVERITY_ERR);
		return;
	}
	POSTCODE_LINUX_2(CRASH_DEV_EXIT_PC, POSTCODE_SEVERITY_INFO);
}

void
bus_create_response(struct visor_device *bus_info, int response)
{
	if (response >= 0)
		bus_info->state.created = 1;

	bus_responder(CONTROLVM_BUS_CREATE, bus_info->pending_msg_hdr,
		      response);

	kfree(bus_info->pending_msg_hdr);
	bus_info->pending_msg_hdr = NULL;
}

void
bus_destroy_response(struct visor_device *bus_info, int response)
{
	bus_responder(CONTROLVM_BUS_DESTROY, bus_info->pending_msg_hdr,
		      response);

	kfree(bus_info->pending_msg_hdr);
	bus_info->pending_msg_hdr = NULL;
}

void
device_create_response(struct visor_device *dev_info, int response)
{
	if (response >= 0)
		dev_info->state.created = 1;

	device_responder(CONTROLVM_DEVICE_CREATE, dev_info->pending_msg_hdr,
			 response);

	kfree(dev_info->pending_msg_hdr);
	dev_info->pending_msg_hdr = NULL;
}

void
device_destroy_response(struct visor_device *dev_info, int response)
{
	device_responder(CONTROLVM_DEVICE_DESTROY, dev_info->pending_msg_hdr,
			 response);

	kfree(dev_info->pending_msg_hdr);
	dev_info->pending_msg_hdr = NULL;
}

void
device_pause_response(struct visor_device *dev_info,
		      int response)
{
	device_changestate_responder(CONTROLVM_DEVICE_CHANGESTATE,
				     dev_info, response,
				     segment_state_standby);

	kfree(dev_info->pending_msg_hdr);
	dev_info->pending_msg_hdr = NULL;
}

void
device_resume_response(struct visor_device *dev_info, int response)
{
	device_changestate_responder(CONTROLVM_DEVICE_CHANGESTATE,
				     dev_info, response,
				     segment_state_running);

	kfree(dev_info->pending_msg_hdr);
	dev_info->pending_msg_hdr = NULL;
}

/**
 * devicedisabled_store() - disables the hotplug device
 * @dev:   sysfs interface variable not utilized in this function
 * @attr:  sysfs interface variable not utilized in this function
 * @buf:   buffer containing the device id
 * @count: the size of the buffer
 *
 * The parahotplug/devicedisabled interface gets called by our support script
 * when an SR-IOV device has been shut down. The ID is passed to the script
 * and then passed back when the device has been removed.
 *
 * Return: the size of the buffer for success or negative for error
 */
static ssize_t devicedisabled_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	unsigned int id;
	int err;

	if (kstrtouint(buf, 10, &id))
		return -EINVAL;

	err = parahotplug_request_complete(id, 0);
	if (err < 0)
		return err;
	return count;
}

/**
 * deviceenabled_store() - enables the hotplug device
 * @dev:   sysfs interface variable not utilized in this function
 * @attr:  sysfs interface variable not utilized in this function
 * @buf:   buffer containing the device id
 * @count: the size of the buffer
 *
 * The parahotplug/deviceenabled interface gets called by our support script
 * when an SR-IOV device has been recovered. The ID is passed to the script
 * and then passed back when the device has been brought back up.
 *
 * Return: the size of the buffer for success or negative for error
 */
static ssize_t deviceenabled_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	unsigned int id;

	if (kstrtouint(buf, 10, &id))
		return -EINVAL;

	parahotplug_request_complete(id, 1);
	return count;
}

static int
visorchipset_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long physaddr = 0;
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	u64 addr = 0;

	/* sv_enable_dfp(); */
	if (offset & (PAGE_SIZE - 1))
		return -ENXIO;	/* need aligned offsets */

	switch (offset) {
	case VISORCHIPSET_MMAP_CONTROLCHANOFFSET:
		vma->vm_flags |= VM_IO;
		if (!*file_controlvm_channel)
			return -ENXIO;

		visorchannel_read
			(*file_controlvm_channel,
			 offsetof(struct spar_controlvm_channel_protocol,
				  gp_control_channel),
			 &addr, sizeof(addr));
		if (!addr)
			return -ENXIO;

		physaddr = (unsigned long)addr;
		if (remap_pfn_range(vma, vma->vm_start,
				    physaddr >> PAGE_SHIFT,
				    vma->vm_end - vma->vm_start,
				    /*pgprot_noncached */
				    (vma->vm_page_prot))) {
			return -EAGAIN;
		}
		break;
	default:
		return -ENXIO;
	}
	return 0;
}

static inline s64 issue_vmcall_query_guest_virtual_time_offset(void)
{
	u64 result = VMCALL_SUCCESS;
	u64 physaddr = 0;

	ISSUE_IO_VMCALL(VMCALL_QUERY_GUEST_VIRTUAL_TIME_OFFSET, physaddr,
			result);
	return result;
}

static inline int issue_vmcall_update_physical_time(u64 adjustment)
{
	int result = VMCALL_SUCCESS;

	ISSUE_IO_VMCALL(VMCALL_UPDATE_PHYSICAL_TIME, adjustment, result);
	return result;
}

static long visorchipset_ioctl(struct file *file, unsigned int cmd,
			       unsigned long arg)
{
	u64 adjustment;
	s64 vrtc_offset;

	switch (cmd) {
	case VMCALL_QUERY_GUEST_VIRTUAL_TIME_OFFSET:
		/* get the physical rtc offset */
		vrtc_offset = issue_vmcall_query_guest_virtual_time_offset();
		if (copy_to_user((void __user *)arg, &vrtc_offset,
				 sizeof(vrtc_offset))) {
			return -EFAULT;
		}
		return 0;
	case VMCALL_UPDATE_PHYSICAL_TIME:
		if (copy_from_user(&adjustment, (void __user *)arg,
				   sizeof(adjustment))) {
			return -EFAULT;
		}
		return issue_vmcall_update_physical_time(adjustment);
	default:
		return -EFAULT;
	}
}

static const struct file_operations visorchipset_fops = {
	.owner = THIS_MODULE,
	.open = visorchipset_open,
	.read = NULL,
	.write = NULL,
	.unlocked_ioctl = visorchipset_ioctl,
	.release = visorchipset_release,
	.mmap = visorchipset_mmap,
};

static int
visorchipset_file_init(dev_t major_dev, struct visorchannel **controlvm_channel)
{
	int rc = 0;

	file_controlvm_channel = controlvm_channel;
	cdev_init(&file_cdev, &visorchipset_fops);
	file_cdev.owner = THIS_MODULE;
	if (MAJOR(major_dev) == 0) {
		rc = alloc_chrdev_region(&major_dev, 0, 1, "visorchipset");
		/* dynamic major device number registration required */
		if (rc < 0)
			return rc;
	} else {
		/* static major device number registration required */
		rc = register_chrdev_region(major_dev, 1, "visorchipset");
		if (rc < 0)
			return rc;
	}
	rc = cdev_add(&file_cdev, MKDEV(MAJOR(major_dev), 0), 1);
	if (rc < 0) {
		unregister_chrdev_region(major_dev, 1);
		return rc;
	}
	return 0;
}

static void
visorchipset_file_cleanup(dev_t major_dev)
{
	if (file_cdev.ops)
		cdev_del(&file_cdev);
	file_cdev.ops = NULL;
	unregister_chrdev_region(major_dev, 1);
}

/**
 * handle_command() - process a controlvm message
 * @inmsg:        the message to process
 * @channel_addr: address of the controlvm channel
 *
 * Return:
 *    false - this function will return false only in the case where the
 *            controlvm message was NOT processed, but processing must be
 *            retried before reading the next controlvm message; a
 *            scenario where this can occur is when we need to throttle
 *            the allocation of memory in which to copy out controlvm
 *            payload data
 *    true  - processing of the controlvm message completed,
 *            either successfully or with an error
 */
static bool
handle_command(struct controlvm_message inmsg, u64 channel_addr)
{
	struct controlvm_message_packet *cmd = &inmsg.cmd;
	u64 parm_addr;
	u32 parm_bytes;
	struct parser_context *parser_ctx = NULL;
	bool local_addr;
	struct controlvm_message ackmsg;

	/* create parsing context if necessary */
	local_addr = (inmsg.hdr.flags.test_message == 1);
	if (channel_addr == 0)
		return true;
	parm_addr = channel_addr + inmsg.hdr.payload_vm_offset;
	parm_bytes = inmsg.hdr.payload_bytes;

	/*
	 * Parameter and channel addresses within test messages actually lie
	 * within our OS-controlled memory. We need to know that, because it
	 * makes a difference in how we compute the virtual address.
	 */
	if (parm_addr && parm_bytes) {
		bool retry = false;

		parser_ctx =
		    parser_init_byte_stream(parm_addr, parm_bytes,
					    local_addr, &retry);
		if (!parser_ctx && retry)
			return false;
	}

	if (!local_addr) {
		controlvm_init_response(&ackmsg, &inmsg.hdr,
					CONTROLVM_RESP_SUCCESS);
		if (controlvm_channel)
			visorchannel_signalinsert(controlvm_channel,
						  CONTROLVM_QUEUE_ACK,
						  &ackmsg);
	}
	switch (inmsg.hdr.id) {
	case CONTROLVM_CHIPSET_INIT:
		chipset_init(&inmsg);
		break;
	case CONTROLVM_BUS_CREATE:
		bus_create(&inmsg);
		break;
	case CONTROLVM_BUS_DESTROY:
		bus_destroy(&inmsg);
		break;
	case CONTROLVM_BUS_CONFIGURE:
		bus_configure(&inmsg, parser_ctx);
		break;
	case CONTROLVM_DEVICE_CREATE:
		my_device_create(&inmsg);
		break;
	case CONTROLVM_DEVICE_CHANGESTATE:
		if (cmd->device_change_state.flags.phys_device) {
			parahotplug_process_message(&inmsg);
		} else {
			/*
			 * save the hdr and cmd structures for later use
			 * when sending back the response to Command
			 */
			my_device_changestate(&inmsg);
			break;
		}
		break;
	case CONTROLVM_DEVICE_DESTROY:
		my_device_destroy(&inmsg);
		break;
	case CONTROLVM_DEVICE_CONFIGURE:
		/* no op for now, just send a respond that we passed */
		if (inmsg.hdr.flags.response_expected)
			controlvm_respond(&inmsg.hdr, CONTROLVM_RESP_SUCCESS);
		break;
	case CONTROLVM_CHIPSET_READY:
		chipset_ready(&inmsg.hdr);
		break;
	case CONTROLVM_CHIPSET_SELFTEST:
		chipset_selftest(&inmsg.hdr);
		break;
	case CONTROLVM_CHIPSET_STOP:
		chipset_notready(&inmsg.hdr);
		break;
	default:
		if (inmsg.hdr.flags.response_expected)
			controlvm_respond
				(&inmsg.hdr,
				 -CONTROLVM_RESP_ERROR_MESSAGE_ID_UNKNOWN);
		break;
	}

	if (parser_ctx) {
		parser_done(parser_ctx);
		parser_ctx = NULL;
	}
	return true;
}

/**
 * read_controlvm_event() - retreives the next message from the
 *                          CONTROLVM_QUEUE_EVENT queue in the controlvm
 *                          channel
 * @msg: pointer to the retrieved message
 *
 * Return: true if a valid message was retrieved or false otherwise
 */
static bool
read_controlvm_event(struct controlvm_message *msg)
{
	if (visorchannel_signalremove(controlvm_channel,
				      CONTROLVM_QUEUE_EVENT, msg)) {
		/* got a message */
		if (msg->hdr.flags.test_message == 1)
			return false;
		return true;
	}
	return false;
}

/**
 * parahotplug_process_list() - remove any request from the list that's been on
 *                              there too long and respond with an error
 */
static void
parahotplug_process_list(void)
{
	struct list_head *pos;
	struct list_head *tmp;

	spin_lock(&parahotplug_request_list_lock);

	list_for_each_safe(pos, tmp, &parahotplug_request_list) {
		struct parahotplug_request *req =
		    list_entry(pos, struct parahotplug_request, list);

		if (!time_after_eq(jiffies, req->expiration))
			continue;

		list_del(pos);
		if (req->msg.hdr.flags.response_expected)
			controlvm_respond_physdev_changestate(
				&req->msg.hdr,
				CONTROLVM_RESP_ERROR_DEVICE_UDEV_TIMEOUT,
				req->msg.cmd.device_change_state.state);
		parahotplug_request_destroy(req);
	}

	spin_unlock(&parahotplug_request_list_lock);
}

static void
controlvm_periodic_work(struct work_struct *work)
{
	struct controlvm_message inmsg;
	bool got_command = false;
	bool handle_command_failed = false;

	while (visorchannel_signalremove(controlvm_channel,
					 CONTROLVM_QUEUE_RESPONSE,
					 &inmsg))
		;
	if (!got_command) {
		if (controlvm_pending_msg_valid) {
			/*
			 * we throttled processing of a prior
			 * msg, so try to process it again
			 * rather than reading a new one
			 */
			inmsg = controlvm_pending_msg;
			controlvm_pending_msg_valid = false;
			got_command = true;
		} else {
			got_command = read_controlvm_event(&inmsg);
		}
	}

	handle_command_failed = false;
	while (got_command && (!handle_command_failed)) {
		most_recent_message_jiffies = jiffies;
		if (handle_command(inmsg,
				   visorchannel_get_physaddr
				   (controlvm_channel)))
			got_command = read_controlvm_event(&inmsg);
		else {
			/*
			 * this is a scenario where throttling
			 * is required, but probably NOT an
			 * error...; we stash the current
			 * controlvm msg so we will attempt to
			 * reprocess it on our next loop
			 */
			handle_command_failed = true;
			controlvm_pending_msg = inmsg;
			controlvm_pending_msg_valid = true;
		}
	}

	/* parahotplug_worker */
	parahotplug_process_list();

	if (time_after(jiffies,
		       most_recent_message_jiffies + (HZ * MIN_IDLE_SECONDS))) {
		/*
		 * it's been longer than MIN_IDLE_SECONDS since we
		 * processed our last controlvm message; slow down the
		 * polling
		 */
		if (poll_jiffies != POLLJIFFIES_CONTROLVMCHANNEL_SLOW)
			poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_SLOW;
	} else {
		if (poll_jiffies != POLLJIFFIES_CONTROLVMCHANNEL_FAST)
			poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_FAST;
	}

	schedule_delayed_work(&periodic_controlvm_work, poll_jiffies);
}

static int
visorchipset_init(struct acpi_device *acpi_device)
{
	int err = -ENODEV;
	u64 addr;
	uuid_le uuid = SPAR_CONTROLVM_CHANNEL_PROTOCOL_UUID;

	addr = controlvm_get_channel_address();
	if (!addr)
		goto error;

	memset(&controlvm_payload_info, 0, sizeof(controlvm_payload_info));

	controlvm_channel = visorchannel_create_with_lock(addr, 0,
							  GFP_KERNEL, uuid);
	if (!controlvm_channel)
		goto error;

	if (SPAR_CONTROLVM_CHANNEL_OK_CLIENT(
		    visorchannel_get_header(controlvm_channel))) {
		initialize_controlvm_payload();
	} else {
		goto error_destroy_channel;
	}

	major_dev = MKDEV(visorchipset_major, 0);
	err = visorchipset_file_init(major_dev, &controlvm_channel);
	if (err < 0)
		goto error_destroy_payload;

	/* if booting in a crash kernel */
	if (is_kdump_kernel())
		INIT_DELAYED_WORK(&periodic_controlvm_work,
				  setup_crash_devices_work_queue);
	else
		INIT_DELAYED_WORK(&periodic_controlvm_work,
				  controlvm_periodic_work);

	most_recent_message_jiffies = jiffies;
	poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_FAST;
	schedule_delayed_work(&periodic_controlvm_work, poll_jiffies);

	visorchipset_platform_device.dev.devt = major_dev;
	if (platform_device_register(&visorchipset_platform_device) < 0) {
		POSTCODE_LINUX_2(DEVICE_REGISTER_FAILURE_PC, DIAG_SEVERITY_ERR);
		err = -ENODEV;
		goto error_cancel_work;
	}
	POSTCODE_LINUX_2(CHIPSET_INIT_SUCCESS_PC, POSTCODE_SEVERITY_INFO);

	err = visorbus_init();
	if (err < 0)
		goto error_unregister;

	return 0;

error_unregister:
	platform_device_unregister(&visorchipset_platform_device);

error_cancel_work:
	cancel_delayed_work_sync(&periodic_controlvm_work);
	visorchipset_file_cleanup(major_dev);

error_destroy_payload:
	destroy_controlvm_payload_info(&controlvm_payload_info);

error_destroy_channel:
	visorchannel_destroy(controlvm_channel);

error:
	POSTCODE_LINUX_3(CHIPSET_INIT_FAILURE_PC, err, POSTCODE_SEVERITY_ERR);
	return err;
}

static int
visorchipset_exit(struct acpi_device *acpi_device)
{
	POSTCODE_LINUX_2(DRIVER_EXIT_PC, POSTCODE_SEVERITY_INFO);

	visorbus_exit();

	cancel_delayed_work_sync(&periodic_controlvm_work);
	destroy_controlvm_payload_info(&controlvm_payload_info);

	visorchannel_destroy(controlvm_channel);

	visorchipset_file_cleanup(visorchipset_platform_device.dev.devt);
	platform_device_unregister(&visorchipset_platform_device);
	POSTCODE_LINUX_2(DRIVER_EXIT_PC, POSTCODE_SEVERITY_INFO);

	return 0;
}

static const struct acpi_device_id unisys_device_ids[] = {
	{"PNP0A07", 0},
	{"", 0},
};

static struct acpi_driver unisys_acpi_driver = {
	.name = "unisys_acpi",
	.class = "unisys_acpi_class",
	.owner = THIS_MODULE,
	.ids = unisys_device_ids,
	.ops = {
		.add = visorchipset_init,
		.remove = visorchipset_exit,
		},
};

MODULE_DEVICE_TABLE(acpi, unisys_device_ids);

static __init uint32_t visorutil_spar_detect(void)
{
	unsigned int eax, ebx, ecx, edx;

	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
		/* check the ID */
		cpuid(UNISYS_SPAR_LEAF_ID, &eax, &ebx, &ecx, &edx);
		return  (ebx == UNISYS_SPAR_ID_EBX) &&
			(ecx == UNISYS_SPAR_ID_ECX) &&
			(edx == UNISYS_SPAR_ID_EDX);
	} else {
		return 0;
	}
}

static int init_unisys(void)
{
	int result;

	if (!visorutil_spar_detect())
		return -ENODEV;

	result = acpi_bus_register_driver(&unisys_acpi_driver);
	if (result)
		return -ENODEV;

	pr_info("Unisys Visorchipset Driver Loaded.\n");
	return 0;
};

static void exit_unisys(void)
{
	acpi_bus_unregister_driver(&unisys_acpi_driver);
}

module_param_named(major, visorchipset_major, int, S_IRUGO);
MODULE_PARM_DESC(visorchipset_major,
		 "major device number to use for the device node");

module_init(init_unisys);
module_exit(exit_unisys);

MODULE_AUTHOR("Unisys");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Supervisor chipset driver for service partition: ver "
		   VERSION);
MODULE_VERSION(VERSION);