/*

   * Copyright (c) 2009, Microsoft Corporation.
   *
   * 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 it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
   * Place - Suite 330, Boston, MA 02111-1307 USA.
   *
   * Authors:
   *   Haiyang Zhang <haiyangz@microsoft.com>
   *   Hank Janssen  <hjanssen@microsoft.com>

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/kernel.h>

  #include <linux/sched.h>
  #include <linux/wait.h>

  #include <linux/mm.h>

  #include <linux/slab.h>

  #include <linux/list.h>

  #include <linux/module.h>

  #include <linux/completion.h>

  #include <linux/hyperv.h>

  #include "hyperv_vmbus.h"

  struct vmbus_channel_message_table_entry {

  	enum vmbus_channel_message_type message_type;

  	void (*message_handler)(struct vmbus_channel_message_header *msg);

  };

  #define MAX_MSG_TYPES                    4
  #define MAX_NUM_DEVICE_CLASSES_SUPPORTED 8

  static const uuid_le

  	supported_device_classes[MAX_NUM_DEVICE_CLASSES_SUPPORTED] = {

  	/* {ba6163d9-04a1-4d29-b605-72e2ffb1dc7f} */

  	/* Storage - SCSI */
  	{

  		.b  = {

  			0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
  			0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f
  		}
  	},

  	/* {F8615163-DF3E-46c5-913F-F2D2F965ED0E} */

  	/* Network */
  	{

  		.b = {

  			0x63, 0x51, 0x61, 0xF8, 0x3E, 0xDF, 0xc5, 0x46,
  			0x91, 0x3F, 0xF2, 0xD2, 0xF9, 0x65, 0xED, 0x0E
  		}
  	},

  	/* {CFA8B69E-5B4A-4cc0-B98B-8BA1A1F3F95A} */

  	/* Input */
  	{

  		.b = {

  			0x9E, 0xB6, 0xA8, 0xCF, 0x4A, 0x5B, 0xc0, 0x4c,
  			0xB9, 0x8B, 0x8B, 0xA1, 0xA1, 0xF3, 0xF9, 0x5A
  		}
  	},

  	/* {32412632-86cb-44a2-9b5c-50d1417354f5} */
  	/* IDE */
  	{

  		.b = {

  			0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
  			0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5
  		}
  	},

  	/* 0E0B6031-5213-4934-818B-38D90CED39DB */
  	/* Shutdown */
  	{

  		.b = {

  			0x31, 0x60, 0x0B, 0X0E, 0x13, 0x52, 0x34, 0x49,
  			0x81, 0x8B, 0x38, 0XD9, 0x0C, 0xED, 0x39, 0xDB
  		}
  	},

  	/* {9527E630-D0AE-497b-ADCE-E80AB0175CAF} */
  	/* TimeSync */
  	{

  		.b = {

  			0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
  			0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf
  		}
  	},

  	/* {57164f39-9115-4e78-ab55-382f3bd5422d} */
  	/* Heartbeat */
  	{

  		.b = {

  			0x39, 0x4f, 0x16, 0x57, 0x15, 0x91, 0x78, 0x4e,
  			0xab, 0x55, 0x38, 0x2f, 0x3b, 0xd5, 0x42, 0x2d
  		}
  	},

  	/* {A9A0F4E7-5A45-4d96-B827-8A841E8C03E6} */
  	/* KVP */
  	{

  		.b = {

  			0xe7, 0xf4, 0xa0, 0xa9, 0x45, 0x5a, 0x96, 0x4d,
  			0xb8, 0x27, 0x8a, 0x84, 0x1e, 0x8c, 0x3,  0xe6
  	}
  	},

  };

  
  /**

   * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message

   * @icmsghdrp: Pointer to msg header structure
   * @icmsg_negotiate: Pointer to negotiate message structure
   * @buf: Raw buffer channel data
   *
   * @icmsghdrp is of type &struct icmsg_hdr.
   * @negop is of type &struct icmsg_negotiate.
   * Set up and fill in default negotiate response message. This response can
   * come from both the vmbus driver and the hv_utils driver. The current api
   * will respond properly to both Windows 2008 and Windows 2008-R2 operating
   * systems.
   *
   * Mainly used by Hyper-V drivers.
   */

  void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  			       struct icmsg_negotiate *negop, u8 *buf)

  {
  	if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
  		icmsghdrp->icmsgsize = 0x10;
  
  		negop = (struct icmsg_negotiate *)&buf[
  			sizeof(struct vmbuspipe_hdr) +
  			sizeof(struct icmsg_hdr)];
  
  		if (negop->icframe_vercnt == 2 &&
  		   negop->icversion_data[1].major == 3) {
  			negop->icversion_data[0].major = 3;
  			negop->icversion_data[0].minor = 0;
  			negop->icversion_data[1].major = 3;
  			negop->icversion_data[1].minor = 0;
  		} else {
  			negop->icversion_data[0].major = 1;
  			negop->icversion_data[0].minor = 0;
  			negop->icversion_data[1].major = 1;
  			negop->icversion_data[1].minor = 0;
  		}
  
  		negop->icframe_vercnt = 1;
  		negop->icmsg_vercnt = 1;
  	}
  }

  EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);

  /*

   * alloc_channel - Allocate and initialize a vmbus channel object

   */

  static struct vmbus_channel *alloc_channel(void)

  {

  	struct vmbus_channel *channel;

  	channel = kzalloc(sizeof(*channel), GFP_ATOMIC);

  	if (!channel)

  		return NULL;

  	spin_lock_init(&channel->inbound_lock);

  	channel->controlwq = create_workqueue("hv_vmbus_ctl");
  	if (!channel->controlwq) {

  		kfree(channel);

  		return NULL;
  	}
  
  	return channel;
  }

  /*

   * release_hannel - Release the vmbus channel object itself

   */

  static void release_channel(struct work_struct *work)

  {

  	struct vmbus_channel *channel = container_of(work,
  						     struct vmbus_channel,
  						     work);

  	destroy_workqueue(channel->controlwq);

  	kfree(channel);

  }

  /*

   * free_channel - Release the resources used by the vmbus channel object

   */

  static void free_channel(struct vmbus_channel *channel)

  {

  	/*
  	 * We have to release the channel's workqueue/thread in the vmbus's
  	 * workqueue/thread context
  	 * ie we can't destroy ourselves.
  	 */

  	INIT_WORK(&channel->work, release_channel);

  	queue_work(vmbus_connection.work_queue, &channel->work);

  }

  /*
   * vmbus_process_rescind_offer -
   * Rescind the offer by initiating a device removal
   */
  static void vmbus_process_rescind_offer(struct work_struct *work)
  {
  	struct vmbus_channel *channel = container_of(work,
  						     struct vmbus_channel,
  						     work);

  	vmbus_device_unregister(channel->device_obj);

  }

  void vmbus_free_channels(void)
  {
  	struct vmbus_channel *channel;
  
  	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
  		vmbus_device_unregister(channel->device_obj);
  		kfree(channel->device_obj);
  		free_channel(channel);
  	}
  }

  /*

   * vmbus_process_offer - Process the offer by creating a channel/device

   * associated with this offer

   */

  static void vmbus_process_offer(struct work_struct *work)

  {

  	struct vmbus_channel *newchannel = container_of(work,
  							struct vmbus_channel,
  							work);

  	struct vmbus_channel *channel;

  	bool fnew = true;

  	int ret;

  	unsigned long flags;

  	/* The next possible work is rescind handling */
  	INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);

  	/* Make sure this is a new offer */

  	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);

  	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {

  		if (!uuid_le_cmp(channel->offermsg.offer.if_type,
  			newchannel->offermsg.offer.if_type) &&
  			!uuid_le_cmp(channel->offermsg.offer.if_instance,
  				newchannel->offermsg.offer.if_instance)) {

  			fnew = false;

  			break;
  		}
  	}

  	if (fnew)

  		list_add_tail(&newchannel->listentry,

  			      &vmbus_connection.chn_list);

  	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

  	if (!fnew) {

  		free_channel(newchannel);

  		return;
  	}

  	/*
  	 * Start the process of binding this offer to the driver
  	 * We need to set the DeviceObject field before calling

  	 * vmbus_child_dev_add()

  	 */

  	newchannel->device_obj = vmbus_device_create(

  		&newchannel->offermsg.offer.if_type,
  		&newchannel->offermsg.offer.if_instance,

  		newchannel);

  	/*
  	 * Add the new device to the bus. This will kick off device-driver
  	 * binding which eventually invokes the device driver's AddDevice()
  	 * method.
  	 */

  	ret = vmbus_device_register(newchannel->device_obj);

  	if (ret != 0) {

  		pr_err("unable to add child device object (relid %d)
  ",

  			   newchannel->offermsg.child_relid);

  		spin_lock_irqsave(&vmbus_connection.channel_lock, flags);

  		list_del(&newchannel->listentry);

  		spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

  		kfree(newchannel->device_obj);

  		free_channel(newchannel);

  	} else {

  		/*
  		 * This state is used to indicate a successful open
  		 * so that when we do close the channel normally, we
  		 * can cleanup properly
  		 */

  		newchannel->state = CHANNEL_OPEN_STATE;

  	}

  }

  /*

   * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.

   *

   */

  static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_offer_channel *offer;

  	struct vmbus_channel *newchannel;

  	uuid_le *guidtype;
  	uuid_le *guidinstance;

  	int i;

  	int fsupported = 0;

  	offer = (struct vmbus_channel_offer_channel *)hdr;
  	for (i = 0; i < MAX_NUM_DEVICE_CLASSES_SUPPORTED; i++) {

  		if (!uuid_le_cmp(offer->offer.if_type,
  				supported_device_classes[i])) {

  			fsupported = 1;

  			break;
  		}
  	}

  	if (!fsupported)

  		return;

  	guidtype = &offer->offer.if_type;
  	guidinstance = &offer->offer.if_instance;

  	/* Allocate the channel object and save this offer. */

  	newchannel = alloc_channel();

  	if (!newchannel) {

  		pr_err("Unable to allocate channel object
  ");

  		return;
  	}

  	memcpy(&newchannel->offermsg, offer,

  	       sizeof(struct vmbus_channel_offer_channel));

  	newchannel->monitor_grp = (u8)offer->monitorid / 32;
  	newchannel->monitor_bit = (u8)offer->monitorid % 32;

  	INIT_WORK(&newchannel->work, vmbus_process_offer);
  	queue_work(newchannel->controlwq, &newchannel->work);

  }

  /*

   * vmbus_onoffer_rescind - Rescind offer handler.

   *
   * We queue a work item to process this offer synchronously
   */

  static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_rescind_offer *rescind;

  	struct vmbus_channel *channel;

  	rescind = (struct vmbus_channel_rescind_offer *)hdr;

  	channel = relid2channel(rescind->child_relid);

  
  	if (channel == NULL)
  		/* Just return here, no channel found */

  		return;

  	/* work is initialized for vmbus_process_rescind_offer() from
  	 * vmbus_process_offer() where the channel got created */
  	queue_work(channel->controlwq, &channel->work);

  }

  /*

   * vmbus_onoffers_delivered -
   * This is invoked when all offers have been delivered.

   *
   * Nothing to do here.
   */

  static void vmbus_onoffers_delivered(

  			struct vmbus_channel_message_header *hdr)

  {

  }

  /*

   * vmbus_onopen_result - Open result handler.

   *
   * This is invoked when we received a response to our channel open request.
   * Find the matching request, copy the response and signal the requesting
   * thread.
   */

  static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_open_result *result;

  	struct vmbus_channel_msginfo *msginfo;
  	struct vmbus_channel_message_header *requestheader;
  	struct vmbus_channel_open_channel *openmsg;

  	unsigned long flags;

  	result = (struct vmbus_channel_open_result *)hdr;

  	/*
  	 * Find the open msg, copy the result and signal/unblock the wait event
  	 */

  	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

  	list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
  				msglistentry) {

  		requestheader =

  			(struct vmbus_channel_message_header *)msginfo->msg;

  		if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {

  			openmsg =

  			(struct vmbus_channel_open_channel *)msginfo->msg;
  			if (openmsg->child_relid == result->child_relid &&
  			    openmsg->openid == result->openid) {
  				memcpy(&msginfo->response.open_result,

  				       result,

  				       sizeof(
  					struct vmbus_channel_open_result));
  				complete(&msginfo->waitevent);

  				break;
  			}
  		}
  	}

  	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

  }

  /*

   * vmbus_ongpadl_created - GPADL created handler.

   *
   * This is invoked when we received a response to our gpadl create request.
   * Find the matching request, copy the response and signal the requesting
   * thread.
   */

  static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_gpadl_created *gpadlcreated;

  	struct vmbus_channel_msginfo *msginfo;
  	struct vmbus_channel_message_header *requestheader;
  	struct vmbus_channel_gpadl_header *gpadlheader;

  	unsigned long flags;

  	gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;

  	/*
  	 * Find the establish msg, copy the result and signal/unblock the wait
  	 * event
  	 */

  	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

  	list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
  				msglistentry) {

  		requestheader =

  			(struct vmbus_channel_message_header *)msginfo->msg;

  		if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {

  			gpadlheader =
  			(struct vmbus_channel_gpadl_header *)requestheader;

  			if ((gpadlcreated->child_relid ==
  			     gpadlheader->child_relid) &&
  			    (gpadlcreated->gpadl == gpadlheader->gpadl)) {
  				memcpy(&msginfo->response.gpadl_created,

  				       gpadlcreated,

  				       sizeof(
  					struct vmbus_channel_gpadl_created));
  				complete(&msginfo->waitevent);

  				break;
  			}
  		}
  	}

  	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

  }

  /*

   * vmbus_ongpadl_torndown - GPADL torndown handler.

   *
   * This is invoked when we received a response to our gpadl teardown request.
   * Find the matching request, copy the response and signal the requesting
   * thread.
   */

  static void vmbus_ongpadl_torndown(

  			struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_gpadl_torndown *gpadl_torndown;

  	struct vmbus_channel_msginfo *msginfo;
  	struct vmbus_channel_message_header *requestheader;
  	struct vmbus_channel_gpadl_teardown *gpadl_teardown;

  	unsigned long flags;

  	gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;

  
  	/*
  	 * Find the open msg, copy the result and signal/unblock the wait event
  	 */

  	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

  	list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
  				msglistentry) {

  		requestheader =

  			(struct vmbus_channel_message_header *)msginfo->msg;

  		if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {

  			gpadl_teardown =
  			(struct vmbus_channel_gpadl_teardown *)requestheader;

  			if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
  				memcpy(&msginfo->response.gpadl_torndown,

  				       gpadl_torndown,

  				       sizeof(
  					struct vmbus_channel_gpadl_torndown));
  				complete(&msginfo->waitevent);

  				break;
  			}
  		}
  	}

  	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

  }

  /*

   * vmbus_onversion_response - Version response handler

   *
   * This is invoked when we received a response to our initiate contact request.
   * Find the matching request, copy the response and signal the requesting
   * thread.
   */

  static void vmbus_onversion_response(

  		struct vmbus_channel_message_header *hdr)

  {

  	struct vmbus_channel_msginfo *msginfo;
  	struct vmbus_channel_message_header *requestheader;

  	struct vmbus_channel_initiate_contact *initiate;

  	struct vmbus_channel_version_response *version_response;

  	unsigned long flags;

  	version_response = (struct vmbus_channel_version_response *)hdr;

  	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

  	list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
  				msglistentry) {

  		requestheader =

  			(struct vmbus_channel_message_header *)msginfo->msg;

  		if (requestheader->msgtype ==
  		    CHANNELMSG_INITIATE_CONTACT) {

  			initiate =
  			(struct vmbus_channel_initiate_contact *)requestheader;

  			memcpy(&msginfo->response.version_response,

  			      version_response,

  			      sizeof(struct vmbus_channel_version_response));

  			complete(&msginfo->waitevent);

  		}
  	}

  	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

  }

  /* Channel message dispatch table */
  static struct vmbus_channel_message_table_entry

  	channel_message_table[CHANNELMSG_COUNT] = {

  	{CHANNELMSG_INVALID,			NULL},
  	{CHANNELMSG_OFFERCHANNEL,		vmbus_onoffer},
  	{CHANNELMSG_RESCIND_CHANNELOFFER,	vmbus_onoffer_rescind},
  	{CHANNELMSG_REQUESTOFFERS,		NULL},
  	{CHANNELMSG_ALLOFFERS_DELIVERED,	vmbus_onoffers_delivered},
  	{CHANNELMSG_OPENCHANNEL,		NULL},
  	{CHANNELMSG_OPENCHANNEL_RESULT,	vmbus_onopen_result},
  	{CHANNELMSG_CLOSECHANNEL,		NULL},
  	{CHANNELMSG_GPADL_HEADER,		NULL},
  	{CHANNELMSG_GPADL_BODY,		NULL},
  	{CHANNELMSG_GPADL_CREATED,		vmbus_ongpadl_created},
  	{CHANNELMSG_GPADL_TEARDOWN,		NULL},
  	{CHANNELMSG_GPADL_TORNDOWN,		vmbus_ongpadl_torndown},
  	{CHANNELMSG_RELID_RELEASED,		NULL},
  	{CHANNELMSG_INITIATE_CONTACT,		NULL},
  	{CHANNELMSG_VERSION_RESPONSE,		vmbus_onversion_response},
  	{CHANNELMSG_UNLOAD,			NULL},

  };

  /*

   * vmbus_onmessage - Handler for channel protocol messages.

   *
   * This is invoked in the vmbus worker thread context.
   */

  void vmbus_onmessage(void *context)

  {

  	struct hv_message *msg = context;

  	struct vmbus_channel_message_header *hdr;

  	int size;

  	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
  	size = msg->header.payload_size;

  	if (hdr->msgtype >= CHANNELMSG_COUNT) {

  		pr_err("Received invalid channel message type %d size %d
  ",

  			   hdr->msgtype, size);

  		print_hex_dump_bytes("", DUMP_PREFIX_NONE,

  				     (unsigned char *)msg->u.payload, size);

  		return;
  	}

  	if (channel_message_table[hdr->msgtype].message_handler)
  		channel_message_table[hdr->msgtype].message_handler(hdr);

  	else

  		pr_err("Unhandled channel message type %d
  ", hdr->msgtype);

  }

  /*

   * vmbus_request_offers - Send a request to get all our pending offers.

   */

  int vmbus_request_offers(void)

  {

  	struct vmbus_channel_message_header *msg;

  	struct vmbus_channel_msginfo *msginfo;

  	int ret, t;

  	msginfo = kmalloc(sizeof(*msginfo) +

  			  sizeof(struct vmbus_channel_message_header),
  			  GFP_KERNEL);

  	if (!msginfo)

  		return -ENOMEM;

  	init_completion(&msginfo->waitevent);

  	msg = (struct vmbus_channel_message_header *)msginfo->msg;

  	msg->msgtype = CHANNELMSG_REQUESTOFFERS;

  	ret = vmbus_post_msg(msg,

  			       sizeof(struct vmbus_channel_message_header));
  	if (ret != 0) {

  		pr_err("Unable to request offers - %d
  ", ret);

  		goto cleanup;
  	}

  	t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);

  	if (t == 0) {

  		ret = -ETIMEDOUT;
  		goto cleanup;

  	}

  cleanup:

  	kfree(msginfo);

  	return ret;
  }

  /* eof */