/* 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/ctype.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/nls.h>
#include <linux/netdevice.h>
#include <linux/uuid.h>
#include <linux/crash_dump.h>

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

#define CURRENT_FILE_PC VISOR_BUS_PC_visorchipset_c

#define POLLJIFFIES_CONTROLVMCHANNEL_FAST 1
#define POLLJIFFIES_CONTROLVMCHANNEL_SLOW 100

#define MAX_CONTROLVM_PAYLOAD_BYTES (1024 * 128)

#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

/*
 * 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

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

struct vmcall_controlvm_addr {
	struct vmcall_io_controlvm_addr_params params;
	int err;
	u64 physaddr;
};

struct visorchipset_device {
	struct acpi_device *acpi_device;
	unsigned long poll_jiffies;
	/* when we got our last controlvm message */
	unsigned long most_recent_message_jiffies;
	struct delayed_work periodic_controlvm_work;
	struct visorchannel *controlvm_channel;
	unsigned long controlvm_payload_bytes_buffered;
	/*
	 * The following variables 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.
	 */
	struct controlvm_message controlvm_pending_msg;
	bool controlvm_pending_msg_valid;
	struct vmcall_controlvm_addr controlvm_addr;
};

static struct visorchipset_device *chipset_dev;

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

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

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 tool_action),
				&tool_action, sizeof(u8));
	if (err)
		return err;

	return sprintf(buf, "%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 err;

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

	err = visorchannel_write
		(chipset_dev->controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  tool_action),
		 &tool_action, sizeof(u8));

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

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

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 efi_spar_ind),
				&efi_spar_indication,
				sizeof(struct efi_spar_indication));

	if (err)
		return err;
	return sprintf(buf, "%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, err;
	struct efi_spar_indication efi_spar_indication;

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

	efi_spar_indication.boot_to_tool = val;
	err = visorchannel_write
		(chipset_dev->controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  efi_spar_ind), &(efi_spar_indication),
		 sizeof(struct efi_spar_indication));

	if (err)
		return err;
	return count;
}
static DEVICE_ATTR_RW(boottotool);

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

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 installation_error),
				&error, sizeof(u32));
	if (err)
		return err;
	return sprintf(buf, "%i\n", error);
}

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

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

	err = visorchannel_write
		(chipset_dev->controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_error),
		 &error, sizeof(u32));
	if (err)
		return err;
	return count;
}
static DEVICE_ATTR_RW(error);

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

	err = visorchannel_read
			(chipset_dev->controlvm_channel,
			 offsetof(struct spar_controlvm_channel_protocol,
				  installation_text_id),
			 &text_id, sizeof(u32));
	if (err)
		return err;

	return sprintf(buf, "%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 err;

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

	err = visorchannel_write
		(chipset_dev->controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_text_id),
		 &text_id, sizeof(u32));
	if (err)
		return err;
	return count;
}
static DEVICE_ATTR_RW(textid);

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

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 installation_remaining_steps),
				&remaining_steps, sizeof(u16));
	if (err)
		return err;

	return sprintf(buf, "%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 err;

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

	err = visorchannel_write
		(chipset_dev->controlvm_channel,
		 offsetof(struct spar_controlvm_channel_protocol,
			  installation_remaining_steps),
		 &remaining_steps, sizeof(u16));
	if (err)
		return err;
	return count;
}
static DEVICE_ATTR_RW(remaining_steps);

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

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

static void parser_done(struct parser_context *ctx)
{
	chipset_dev->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;

	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);
	if (!value)
		return NULL;
	if (value_length > 0)
		memcpy(value, pscan, value_length);
	((u8 *)(value))[value_length] = '\0';
	return value;
}

static void *
parser_name_get(struct parser_context *ctx)
{
	struct spar_controlvm_parameters_header *phdr = NULL;

	phdr = (struct spar_controlvm_parameters_header *)(ctx->data);

	if (phdr->name_offset + phdr->name_length > ctx->param_bytes)
		return NULL;

	ctx->curr = ctx->data + phdr->name_offset;
	ctx->bytes_remaining = phdr->name_length;
	return parser_string_get(ctx);
}

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 int
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;
	return visorchannel_signalinsert(chipset_dev->controlvm_channel,
					 CONTROLVM_QUEUE_REQUEST, &outmsg);
}

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

	if (chipset_inited) {
		rc = -CONTROLVM_RESP_ALREADY_DONE;
		res = -EIO;
		goto out_respond;
	}
	chipset_inited = 1;

	/*
	 * 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)
		res = controlvm_respond_chipset_init(&inmsg->hdr, rc, features);

	return res;
}

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

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

	if (state) {
		outmsg.cmd.device_change_state.state = *state;
		outmsg.cmd.device_change_state.flags.phys_device = 1;
	}

	return visorchannel_signalinsert(chipset_dev->controlvm_channel,
					 CONTROLVM_QUEUE_REQUEST, &outmsg);
}

enum crash_obj_type {
	CRASH_DEV,
	CRASH_BUS,
};

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

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 saved_crash_message_count),
				&local_crash_msg_count, sizeof(u16));
	if (err) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read message count\n");
		return err;
	}

	if (local_crash_msg_count != CONTROLVM_CRASHMSG_MAX) {
		dev_err(&chipset_dev->acpi_device->dev,
			"invalid number of messages\n");
		return -EIO;
	}

	err = visorchannel_read(chipset_dev->controlvm_channel,
				offsetof(struct spar_controlvm_channel_protocol,
					 saved_crash_message_offset),
				&local_crash_msg_offset, sizeof(u32));
	if (err) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read offset\n");
		return err;
	}

	switch (typ) {
	case CRASH_DEV:
		local_crash_msg_offset += sizeof(struct controlvm_message);
		err = visorchannel_write(chipset_dev->controlvm_channel,
					 local_crash_msg_offset,
					 msg,
					 sizeof(struct controlvm_message));
		if (err) {
			dev_err(&chipset_dev->acpi_device->dev,
				"failed to write dev msg\n");
			return err;
		}
		break;
	case CRASH_BUS:
		err = visorchannel_write(chipset_dev->controlvm_channel,
					 local_crash_msg_offset,
					 msg,
					 sizeof(struct controlvm_message));
		if (err) {
			dev_err(&chipset_dev->acpi_device->dev,
				"failed to write bus msg\n");
			return err;
		}
		break;
	default:
		dev_err(&chipset_dev->acpi_device->dev,
			"Invalid crash_obj_type\n");
		break;
	}
	return 0;
}

static int
controlvm_responder(enum controlvm_id cmd_id,
		    struct controlvm_message_header *pending_msg_hdr,
		    int response)
{
	if (!pending_msg_hdr)
		return -EIO;

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

	return controlvm_respond(pending_msg_hdr, response, NULL);
}

static int
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 -EIO;
	if (p->pending_msg_hdr->id != cmd_id)
		return -EINVAL;

	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;

	return visorchannel_signalinsert(chipset_dev->controlvm_channel,
					 CONTROLVM_QUEUE_REQUEST, &outmsg);
}

static int
bus_create(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	struct controlvm_message_header *pmsg_hdr = NULL;
	u32 bus_no = cmd->create_bus.bus_no;
	struct visor_device *bus_info;
	struct visorchannel *visorchannel;
	int err;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (bus_info && (bus_info->state.created == 1)) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed bus_create: already exists\n");
		err = -EEXIST;
		goto err_respond;
	}

	bus_info = kzalloc(sizeof(*bus_info), GFP_KERNEL);
	if (!bus_info) {
		err = -ENOMEM;
		goto err_respond;
	}

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

	if (uuid_le_cmp(cmd->create_bus.bus_inst_uuid, spar_siovm_uuid) == 0) {
		err = save_crash_message(inmsg, CRASH_BUS);
		if (err)
			goto err_free_bus_info;
	}

	if (inmsg->hdr.flags.response_expected == 1) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr),
				   GFP_KERNEL);
		if (!pmsg_hdr) {
			err = -ENOMEM;
			goto err_free_bus_info;
		}

		memcpy(pmsg_hdr, &inmsg->hdr,
		       sizeof(struct controlvm_message_header));
		bus_info->pending_msg_hdr = pmsg_hdr;
	}

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

	if (!visorchannel) {
		err = -ENOMEM;
		goto err_free_pending_msg;
	}
	bus_info->visorchannel = visorchannel;

	/* Response will be handled by chipset_bus_create */
	err = chipset_bus_create(bus_info);
	/* If error chipset_bus_create didn't respond, need to respond here */
	if (err)
		goto err_destroy_channel;

	return 0;

err_destroy_channel:
	visorchannel_destroy(visorchannel);

err_free_pending_msg:
	kfree(bus_info->pending_msg_hdr);

err_free_bus_info:
	kfree(bus_info);

err_respond:
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

static int
bus_destroy(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	struct controlvm_message_header *pmsg_hdr = NULL;
	u32 bus_no = cmd->destroy_bus.bus_no;
	struct visor_device *bus_info;
	int err;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info) {
		err = -ENODEV;
		goto err_respond;
	}
	if (bus_info->state.created == 0) {
		err = -ENOENT;
		goto err_respond;
	}
	if (bus_info->pending_msg_hdr) {
		/* only non-NULL if dev is still waiting on a response */
		err = -EEXIST;
		goto err_respond;
	}
	if (inmsg->hdr.flags.response_expected == 1) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			err = -ENOMEM;
			goto err_respond;
		}

		memcpy(pmsg_hdr, &inmsg->hdr,
		       sizeof(struct controlvm_message_header));
		bus_info->pending_msg_hdr = pmsg_hdr;
	}

	/* Response will be handled by chipset_bus_destroy */
	chipset_bus_destroy(bus_info);
	return 0;

err_respond:
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

static int
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 err = 0;

	bus_no = cmd->configure_bus.bus_no;
	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info) {
		err = -EINVAL;
		goto err_respond;
	} else if (bus_info->state.created == 0) {
		err = -EINVAL;
		goto err_respond;
	} else if (bus_info->pending_msg_hdr) {
		err = -EIO;
		goto err_respond;
	}

	err = visorchannel_set_clientpartition
		(bus_info->visorchannel,
		 cmd->configure_bus.guest_handle);
	if (err)
		goto err_respond;

	if (parser_ctx) {
		bus_info->partition_uuid = parser_id_get(parser_ctx);
		bus_info->name = parser_name_get(parser_ctx);
	}

	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return 0;

err_respond:
	dev_err(&chipset_dev->acpi_device->dev,
		"bus_configured exited with err: %d\n", err);
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

static int
my_device_create(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	struct controlvm_message_header *pmsg_hdr = NULL;
	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 err;

	bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
	if (!bus_info) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to get bus by id: %d\n", bus_no);
		err = -ENODEV;
		goto err_respond;
	}

	if (bus_info->state.created == 0) {
		dev_err(&chipset_dev->acpi_device->dev,
			"bus not created, id: %d\n", bus_no);
		err = -EINVAL;
		goto err_respond;
	}

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (dev_info && (dev_info->state.created == 1)) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to get bus by id: %d/%d\n", bus_no, dev_no);
		err = -EEXIST;
		goto err_respond;
	}

	dev_info = kzalloc(sizeof(*dev_info), GFP_KERNEL);
	if (!dev_info) {
		err = -ENOMEM;
		goto err_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;

	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) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to create visorchannel: %d/%d\n",
			bus_no, dev_no);
		err = -ENOMEM;
		goto err_free_dev_info;
	}
	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) {
		err = save_crash_message(inmsg, CRASH_DEV);
		if (err)
			goto err_destroy_visorchannel;
	}

	if (inmsg->hdr.flags.response_expected == 1) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			err = -ENOMEM;
			goto err_destroy_visorchannel;
		}

		memcpy(pmsg_hdr, &inmsg->hdr,
		       sizeof(struct controlvm_message_header));
		dev_info->pending_msg_hdr = pmsg_hdr;
	}
	/* Chipset_device_create will send response */
	err = chipset_device_create(dev_info);
	if (err)
		goto err_destroy_visorchannel;

	return 0;

err_destroy_visorchannel:
	visorchannel_destroy(visorchannel);

err_free_dev_info:
	kfree(dev_info);

err_respond:
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

static int
my_device_changestate(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	struct controlvm_message_header *pmsg_hdr = NULL;
	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 err = 0;

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (!dev_info) {
		err = -ENODEV;
		goto err_respond;
	}
	if (dev_info->state.created == 0) {
		err = -EINVAL;
		goto err_respond;
	}
	if (dev_info->pending_msg_hdr) {
		/* only non-NULL if dev is still waiting on a response */
		err = -EIO;
		goto err_respond;
	}
	if (inmsg->hdr.flags.response_expected == 1) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			err = -ENOMEM;
			goto err_respond;
		}

		memcpy(pmsg_hdr, &inmsg->hdr,
		       sizeof(struct controlvm_message_header));
		dev_info->pending_msg_hdr = pmsg_hdr;
	}

	if (state.alive == segment_state_running.alive &&
	    state.operating == segment_state_running.operating)
		/* Response will be sent from chipset_device_resume */
		err = 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.
		 * Response will be sent from chipset_device_pause.
		 */
		err = chipset_device_pause(dev_info);
	if (err)
		goto err_respond;

	return 0;

err_respond:
	dev_err(&chipset_dev->acpi_device->dev, "failed: %d\n", err);
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

static int
my_device_destroy(struct controlvm_message *inmsg)
{
	struct controlvm_message_packet *cmd = &inmsg->cmd;
	struct controlvm_message_header *pmsg_hdr = NULL;
	u32 bus_no = cmd->destroy_device.bus_no;
	u32 dev_no = cmd->destroy_device.dev_no;
	struct visor_device *dev_info;
	int err;

	dev_info = visorbus_get_device_by_id(bus_no, dev_no, NULL);
	if (!dev_info) {
		err = -ENODEV;
		goto err_respond;
	}
	if (dev_info->state.created == 0) {
		err = -EINVAL;
		goto err_respond;
	}

	if (dev_info->pending_msg_hdr) {
		/* only non-NULL if dev is still waiting on a response */
		err = -EIO;
		goto err_respond;
	}
	if (inmsg->hdr.flags.response_expected == 1) {
		pmsg_hdr = kzalloc(sizeof(*pmsg_hdr), GFP_KERNEL);
		if (!pmsg_hdr) {
			err = -ENOMEM;
			goto err_respond;
		}

		memcpy(pmsg_hdr, &inmsg->hdr,
		       sizeof(struct controlvm_message_header));
		dev_info->pending_msg_hdr = pmsg_hdr;
	}

	chipset_device_destroy(dev_info);
	return 0;

err_respond:
	if (inmsg->hdr.flags.response_expected == 1)
		controlvm_responder(inmsg->hdr.id, &inmsg->hdr, err);
	return err;
}

/*
 * The general parahotplug flow works as follows. The visorchipset 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
 * /sys/devices/platform/visorchipset/parahotplug, which causes the
 * parahotplug store functions 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 /sys
 *                         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);
	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);
}

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

/*
 * 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 /sys 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(
				       &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;
}

/*
 * 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;
}
static DEVICE_ATTR_WO(devicedisabled);

/*
 * 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 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 const 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
};

/*
 * 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 int
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);

	return kobject_uevent_env(&chipset_dev->acpi_device->dev.kobj,
				  KOBJ_CHANGE, envp);
}

/*
 * 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 int
parahotplug_process_message(struct controlvm_message *inmsg)
{
	struct parahotplug_request *req;
	int err;

	req = parahotplug_request_create(inmsg);

	if (!req)
		return -ENOMEM;

	/*
	 * For enable messages, just respond with success right away, we don't
	 * need to wait to see if the enable was successful.
	 */
	if (inmsg->cmd.device_change_state.state.active) {
		err = parahotplug_request_kickoff(req);
		if (err)
			goto err_respond;
		controlvm_respond(&inmsg->hdr, CONTROLVM_RESP_SUCCESS,
				  &inmsg->cmd.device_change_state.state);
		parahotplug_request_destroy(req);
		return 0;
	}

	/*
	 * 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);

	err = parahotplug_request_kickoff(req);
	if (err)
		goto err_respond;
	return 0;

err_respond:
	controlvm_respond(&inmsg->hdr, err,
			  &inmsg->cmd.device_change_state.state);
	return err;
}

/*
 * chipset_ready_uevent() - sends chipset_ready action
 *
 * Send ACTION=online for DEVPATH=/sys/devices/platform/visorchipset.
 *
 * Return: 0 on success, negative on failure
 */
static int
chipset_ready_uevent(struct controlvm_message_header *msg_hdr)
{
	int res;

	res = kobject_uevent(&chipset_dev->acpi_device->dev.kobj,
			     KOBJ_ONLINE);

	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, res, NULL);

	return res;
}

/*
 * chipset_selftest_uevent() - sends chipset_selftest action
 *
 * Send ACTION=online for DEVPATH=/sys/devices/platform/visorchipset.
 *
 * Return: 0 on success, negative on failure
 */
static int
chipset_selftest_uevent(struct controlvm_message_header *msg_hdr)
{
	char env_selftest[20];
	char *envp[] = { env_selftest, NULL };
	int res;

	sprintf(env_selftest, "SPARSP_SELFTEST=%d", 1);
	res = kobject_uevent_env(&chipset_dev->acpi_device->dev.kobj,
				 KOBJ_CHANGE, envp);

	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, res, NULL);

	return res;
}

/*
 * chipset_notready_uevent() - sends chipset_notready action
 *
 * Send ACTION=offline for DEVPATH=/sys/devices/platform/visorchipset.
 *
 * Return: 0 on success, negative on failure
 */
static int
chipset_notready_uevent(struct controlvm_message_header *msg_hdr)
{
	int res;

	res = kobject_uevent(&chipset_dev->acpi_device->dev.kobj,
			     KOBJ_OFFLINE);
	if (msg_hdr->flags.response_expected)
		controlvm_respond(msg_hdr, res, NULL);

	return res;
}

static int unisys_vmcall(unsigned long tuple, unsigned long param)
{
	int result = 0;
	unsigned int cpuid_eax, cpuid_ebx, cpuid_ecx, cpuid_edx;
	unsigned long reg_ebx;
	unsigned long reg_ecx;

	reg_ebx = param & 0xFFFFFFFF;
	reg_ecx = param >> 32;

	cpuid(0x00000001, &cpuid_eax, &cpuid_ebx, &cpuid_ecx, &cpuid_edx);
	if (!(cpuid_ecx & 0x80000000))
		return -EPERM;

	__asm__ __volatile__(".byte 0x00f, 0x001, 0x0c1" : "=a"(result) :
		"a"(tuple), "b"(reg_ebx), "c"(reg_ecx));

	if (result)
		goto error;

	return 0;

error: /* Need to convert from VMCALL error codes to Linux */
	switch (result) {
	case VMCALL_RESULT_INVALID_PARAM:
		return -EINVAL;
	case VMCALL_RESULT_DATA_UNAVAILABLE:
		return -ENODEV;
	default:
		return -EFAULT;
	}
}
static unsigned int
issue_vmcall_io_controlvm_addr(u64 *control_addr, u32 *control_bytes)
{
	chipset_dev->controlvm_addr.physaddr = virt_to_phys(
					   &chipset_dev->controlvm_addr.params);
	chipset_dev->controlvm_addr.err = unisys_vmcall(VMCALL_CONTROLVM_ADDR,
					  chipset_dev->controlvm_addr.physaddr);
	if (chipset_dev->controlvm_addr.err)
		return chipset_dev->controlvm_addr.err;

	*control_addr = chipset_dev->controlvm_addr.params.address;
	*control_bytes = chipset_dev->controlvm_addr.params.channel_bytes;

	return 0;
}

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

	if (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;

	/* 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(chipset_dev->controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_count),
			      &local_crash_msg_count, sizeof(u16)) < 0) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read channel\n");
		return;
	}

	if (local_crash_msg_count != CONTROLVM_CRASHMSG_MAX) {
		dev_err(&chipset_dev->acpi_device->dev,
			"invalid count\n");
		return;
	}

	/* get saved crash message offset */
	if (visorchannel_read(chipset_dev->controlvm_channel,
			      offsetof(struct spar_controlvm_channel_protocol,
				       saved_crash_message_offset),
			      &local_crash_msg_offset, sizeof(u32)) < 0) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read channel\n");
		return;
	}

	/* read create device message for storage bus offset */
	if (visorchannel_read(chipset_dev->controlvm_channel,
			      local_crash_msg_offset,
			      &local_crash_bus_msg,
			      sizeof(struct controlvm_message)) < 0) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read channel\n");
		return;
	}

	/* read create device message for storage device */
	if (visorchannel_read(chipset_dev->controlvm_channel,
			      local_crash_msg_offset +
			      sizeof(struct controlvm_message),
			      &local_crash_dev_msg,
			      sizeof(struct controlvm_message)) < 0) {
		dev_err(&chipset_dev->acpi_device->dev,
			"failed to read channel\n");
		return;
	}

	/* reuse IOVM create bus message */
	if (!local_crash_bus_msg.cmd.create_bus.channel_addr) {
		dev_err(&chipset_dev->acpi_device->dev,
			"no valid create_bus message\n");
		return;
	}
	bus_create(&local_crash_bus_msg);

	/* reuse create device message for storage device */
	if (!local_crash_dev_msg.cmd.create_device.channel_addr) {
		dev_err(&chipset_dev->acpi_device->dev,
			"no valid create_device message\n");
		return;
	}
	my_device_create(&local_crash_dev_msg);
}

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

	controlvm_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)
{
	controlvm_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;

	controlvm_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)
{
	controlvm_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;
}

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;

	*retry = false;

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

	return ctx;

err_finish_ctx:
	parser_done(ctx);
	return NULL;
}

/*
 * handle_command() - process a controlvm message
 * @inmsg:        the message to process
 * @channel_addr: address of the controlvm channel
 *
 * Return:
 *	0	- Successfully processed the message
 *	-EAGAIN - ControlVM message was not processed and should be retried
 *		  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.
 *	< 0	- error: ControlVM message was processed but an error occurred.
 */
static int
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;
	int err = 0;

	/* create parsing context if necessary */
	local_addr = (inmsg.hdr.flags.test_message == 1);
	if (channel_addr == 0)
		return -EINVAL;

	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 -EAGAIN;
	}

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

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

/*
 * read_controlvm_event() - retreives the next message from the
 *                          CONTROLVM_QUEUE_EVENT queue in the controlvm
 *                          channel
 * @msg: pointer to the retrieved message
 *
 * Return: 0 if valid message was retrieved or -error
 */
static int
read_controlvm_event(struct controlvm_message *msg)
{
	int err;

	err = visorchannel_signalremove(chipset_dev->controlvm_channel,
					CONTROLVM_QUEUE_EVENT, msg);
	if (err)
		return err;

	/* got a message */
	if (msg->hdr.flags.test_message == 1)
		return -EINVAL;

	return 0;
}

/*
 * 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(
				&req->msg.hdr,
				CONTROLVM_RESP_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;
	int count = 0;
	int err;

	/* Drain the RESPONSE queue make it empty */
	do {
		err = visorchannel_signalremove(chipset_dev->controlvm_channel,
						CONTROLVM_QUEUE_RESPONSE,
						&inmsg);
	} while ((!err) && (++count < CONTROLVM_MESSAGE_MAX));

	if (err != -EAGAIN)
		goto schedule_out;

	if (chipset_dev->controlvm_pending_msg_valid) {
		/*
		 * we throttled processing of a prior
		 * msg, so try to process it again
		 * rather than reading a new one
		 */
		inmsg = chipset_dev->controlvm_pending_msg;
		chipset_dev->controlvm_pending_msg_valid = false;
		err = 0;
	} else {
		err = read_controlvm_event(&inmsg);
	}

	while (!err) {
		chipset_dev->most_recent_message_jiffies = jiffies;
		err = handle_command(inmsg,
				     visorchannel_get_physaddr
				     (chipset_dev->controlvm_channel));
		if (err == -EAGAIN) {
			chipset_dev->controlvm_pending_msg = inmsg;
			chipset_dev->controlvm_pending_msg_valid = true;
			break;
		}

		err = read_controlvm_event(&inmsg);
	}

	/* parahotplug_worker */
	parahotplug_process_list();

schedule_out:
	if (time_after(jiffies, chipset_dev->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 (chipset_dev->poll_jiffies !=
					      POLLJIFFIES_CONTROLVMCHANNEL_SLOW)
			chipset_dev->poll_jiffies =
					      POLLJIFFIES_CONTROLVMCHANNEL_SLOW;
	} else {
		if (chipset_dev->poll_jiffies !=
					      POLLJIFFIES_CONTROLVMCHANNEL_FAST)
			chipset_dev->poll_jiffies =
					      POLLJIFFIES_CONTROLVMCHANNEL_FAST;
	}

	schedule_delayed_work(&chipset_dev->periodic_controlvm_work,
			      chipset_dev->poll_jiffies);
}

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

	chipset_dev = kzalloc(sizeof(*chipset_dev), GFP_KERNEL);
	if (!chipset_dev)
		goto error;

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

	acpi_device->driver_data = chipset_dev;

	chipset_dev->acpi_device = acpi_device;
	chipset_dev->poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_FAST;
	controlvm_channel = visorchannel_create_with_lock(addr,
							  0, GFP_KERNEL, uuid);

	if (!controlvm_channel)
		goto error_free_chipset_dev;

	chipset_dev->controlvm_channel = controlvm_channel;

	err = sysfs_create_groups(&chipset_dev->acpi_device->dev.kobj,
				  visorchipset_dev_groups);
	if (err < 0)
		goto error_destroy_channel;

	if (!SPAR_CONTROLVM_CHANNEL_OK_CLIENT(
				visorchannel_get_header(controlvm_channel)))
		goto error_delete_groups;

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

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

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

	return 0;

error_cancel_work:
	cancel_delayed_work_sync(&chipset_dev->periodic_controlvm_work);

error_delete_groups:
	sysfs_remove_groups(&chipset_dev->acpi_device->dev.kobj,
			    visorchipset_dev_groups);

error_destroy_channel:
	visorchannel_destroy(chipset_dev->controlvm_channel);

error_free_chipset_dev:
	kfree(chipset_dev);

error:
	dev_err(&acpi_device->dev, "failed with error %d\n", err);
	return err;
}

static int
visorchipset_exit(struct acpi_device *acpi_device)
{
	visorbus_exit();
	cancel_delayed_work_sync(&chipset_dev->periodic_controlvm_work);
	sysfs_remove_groups(&chipset_dev->acpi_device->dev.kobj,
			    visorchipset_dev_groups);

	visorchannel_destroy(chipset_dev->controlvm_channel);
	kfree(chipset_dev);

	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 int 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_init(init_unisys);
module_exit(exit_unisys);

MODULE_AUTHOR("Unisys");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("s-Par visorbus driver for virtual device buses");