/*
 *
 * 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>
 *
 */


#ifndef _CHANNEL_MGMT_H_
#define _CHANNEL_MGMT_H_

#include <linux/list.h>
#include <linux/timer.h>
#include "ring_buffer.h"
#include "vmbus_channel_interface.h"
#include "vmbus_packet_format.h"

/* Version 1 messages */
enum vmbus_channel_message_type {
	CHANNELMSG_INVALID			=  0,
	CHANNELMSG_OFFERCHANNEL		=  1,
	CHANNELMSG_RESCIND_CHANNELOFFER	=  2,
	CHANNELMSG_REQUESTOFFERS		=  3,
	CHANNELMSG_ALLOFFERS_DELIVERED	=  4,
	CHANNELMSG_OPENCHANNEL		=  5,
	CHANNELMSG_OPENCHANNEL_RESULT		=  6,
	CHANNELMSG_CLOSECHANNEL		=  7,
	CHANNELMSG_GPADL_HEADER		=  8,
	CHANNELMSG_GPADL_BODY			=  9,
	CHANNELMSG_GPADL_CREATED		= 10,
	CHANNELMSG_GPADL_TEARDOWN		= 11,
	CHANNELMSG_GPADL_TORNDOWN		= 12,
	CHANNELMSG_RELID_RELEASED		= 13,
	CHANNELMSG_INITIATE_CONTACT		= 14,
	CHANNELMSG_VERSION_RESPONSE		= 15,
	CHANNELMSG_UNLOAD			= 16,
#ifdef VMBUS_FEATURE_PARENT_OR_PEER_MEMORY_MAPPED_INTO_A_CHILD
	CHANNELMSG_VIEWRANGE_ADD		= 17,
	CHANNELMSG_VIEWRANGE_REMOVE		= 18,
#endif
	CHANNELMSG_COUNT
};

struct vmbus_channel_message_header {
	enum vmbus_channel_message_type msgtype;
	u32 padding;
} __attribute__((packed));

/* Query VMBus Version parameters */
struct vmbus_channel_query_vmbus_version {
	struct vmbus_channel_message_header header;
	u32 version;
} __attribute__((packed));

/* VMBus Version Supported parameters */
struct vmbus_channel_version_supported {
	struct vmbus_channel_message_header header;
	bool version_supported;
} __attribute__((packed));

/* Offer Channel parameters */
struct vmbus_channel_offer_channel {
	struct vmbus_channel_message_header header;
	struct vmbus_channel_offer offer;
	u32 child_relid;
	u8 monitorid;
	bool monitor_allocated;
} __attribute__((packed));

/* Rescind Offer parameters */
struct vmbus_channel_rescind_offer {
	struct vmbus_channel_message_header header;
	u32 child_relid;
} __attribute__((packed));

/*
 * Request Offer -- no parameters, SynIC message contains the partition ID
 * Set Snoop -- no parameters, SynIC message contains the partition ID
 * Clear Snoop -- no parameters, SynIC message contains the partition ID
 * All Offers Delivered -- no parameters, SynIC message contains the partition
 *		           ID
 * Flush Client -- no parameters, SynIC message contains the partition ID
 */

/* Open Channel parameters */
struct vmbus_channel_open_channel {
	struct vmbus_channel_message_header header;

	/* Identifies the specific VMBus channel that is being opened. */
	u32 child_relid;

	/* ID making a particular open request at a channel offer unique. */
	u32 openid;

	/* GPADL for the channel's ring buffer. */
	u32 ringbuffer_gpadlhandle;

	/* GPADL for the channel's server context save area. */
	u32 server_contextarea_gpadlhandle;

	/*
	* The upstream ring buffer begins at offset zero in the memory
	* described by RingBufferGpadlHandle. The downstream ring buffer
	* follows it at this offset (in pages).
	*/
	u32 downstream_ringbuffer_pageoffset;

	/* User-specific data to be passed along to the server endpoint. */
	unsigned char userdata[MAX_USER_DEFINED_BYTES];
} __attribute__((packed));

/* Open Channel Result parameters */
struct vmbus_channel_open_result {
	struct vmbus_channel_message_header header;
	u32 child_relid;
	u32 openid;
	u32 status;
} __attribute__((packed));

/* Close channel parameters; */
struct vmbus_channel_close_channel {
	struct vmbus_channel_message_header header;
	u32 child_relid;
} __attribute__((packed));

/* Channel Message GPADL */
#define GPADL_TYPE_RING_BUFFER		1
#define GPADL_TYPE_SERVER_SAVE_AREA	2
#define GPADL_TYPE_TRANSACTION		8

/*
 * The number of PFNs in a GPADL message is defined by the number of
 * pages that would be spanned by ByteCount and ByteOffset.  If the
 * implied number of PFNs won't fit in this packet, there will be a
 * follow-up packet that contains more.
 */
struct vmbus_channel_gpadl_header {
	struct vmbus_channel_message_header header;
	u32 child_relid;
	u32 gpadl;
	u16 range_buflen;
	u16 rangecount;
	struct gpa_range range[0];
} __attribute__((packed));

/* This is the followup packet that contains more PFNs. */
struct vmbus_channel_gpadl_body {
	struct vmbus_channel_message_header header;
	u32 msgnumber;
	u32 gpadl;
	u64 pfn[0];
} __attribute__((packed));

struct vmbus_channel_gpadl_created {
	struct vmbus_channel_message_header header;
	u32 child_relid;
	u32 gpadl;
	u32 creation_status;
} __attribute__((packed));

struct vmbus_channel_gpadl_teardown {
	struct vmbus_channel_message_header header;
	u32 child_relid;
	u32 gpadl;
} __attribute__((packed));

struct vmbus_channel_gpadl_torndown {
	struct vmbus_channel_message_header header;
	u32 gpadl;
} __attribute__((packed));

#ifdef VMBUS_FEATURE_PARENT_OR_PEER_MEMORY_MAPPED_INTO_A_CHILD
struct vmbus_channel_view_range_add {
	struct vmbus_channel_message_header header;
	PHYSICAL_ADDRESS viewrange_base;
	u64 viewrange_length;
	u32 child_relid;
} __attribute__((packed));

struct vmbus_channel_view_range_remove {
	struct vmbus_channel_message_header header;
	PHYSICAL_ADDRESS viewrange_base;
	u32 child_relid;
} __attribute__((packed));
#endif

struct vmbus_channel_relid_released {
	struct vmbus_channel_message_header header;
	u32 child_relid;
} __attribute__((packed));

struct vmbus_channel_initiate_contact {
	struct vmbus_channel_message_header header;
	u32 vmbus_version_requested;
	u32 padding2;
	u64 interrupt_page;
	u64 monitor_page1;
	u64 monitor_page2;
} __attribute__((packed));

struct vmbus_channel_version_response {
	struct vmbus_channel_message_header header;
	bool version_supported;
} __attribute__((packed));

enum vmbus_channel_state {
	CHANNEL_OFFER_STATE,
	CHANNEL_OPENING_STATE,
	CHANNEL_OPEN_STATE,
};

struct vmbus_channel {
	struct list_head listentry;

	struct hv_device *device_obj;

	struct timer_list poll_timer; /* SA-111 workaround */
	struct work_struct work;

	enum vmbus_channel_state state;

	struct vmbus_channel_offer_channel offermsg;
	/*
	 * These are based on the OfferMsg.MonitorId.
	 * Save it here for easy access.
	 */
	u8 monitor_grp;
	u8 monitor_bit;

	u32 ringbuffer_gpadlhandle;

	/* Allocated memory for ring buffer */
	void *ringbuffer_pages;
	u32 ringbuffer_pagecount;
	struct hv_ring_buffer_info outbound;	/* send to parent */
	struct hv_ring_buffer_info inbound;	/* receive from parent */
	spinlock_t inbound_lock;
	struct workqueue_struct *controlwq;

	/* Channel callback are invoked in this workqueue context */
	/* HANDLE dataWorkQueue; */

	void (*onchannel_callback)(void *context);
	void *channel_callback_context;
};

struct vmbus_channel_debug_info {
	u32 relid;
	enum vmbus_channel_state state;
	struct hv_guid interfacetype;
	struct hv_guid interface_instance;
	u32 monitorid;
	u32 servermonitor_pending;
	u32 servermonitor_latency;
	u32 servermonitor_connectionid;
	u32 clientmonitor_pending;
	u32 clientmonitor_latency;
	u32 clientmonitor_connectionid;

	struct hv_ring_buffer_debug_info inbound;
	struct hv_ring_buffer_debug_info outbound;
};

/*
 * Represents each channel msg on the vmbus connection This is a
 * variable-size data structure depending on the msg type itself
 */
struct vmbus_channel_msginfo {
	/* Bookkeeping stuff */
	struct list_head msglistentry;

	/* So far, this is only used to handle gpadl body message */
	struct list_head submsglist;

	/* Synchronize the request/response if needed */
	struct osd_waitevent *waitevent;

	union {
		struct vmbus_channel_version_supported version_supported;
		struct vmbus_channel_open_result open_result;
		struct vmbus_channel_gpadl_torndown gpadl_torndown;
		struct vmbus_channel_gpadl_created gpadl_created;
		struct vmbus_channel_version_response version_response;
	} response;

	u32 msgsize;
	/*
	 * The channel message that goes out on the "wire".
	 * It will contain at minimum the VMBUS_CHANNEL_MESSAGE_HEADER header
	 */
	unsigned char msg[0];
};


void free_channel(struct vmbus_channel *channel);

void vmbus_onmessage(void *context);

int vmbus_request_offers(void);

void vmbus_release_unattached_channels(void);

#endif /* _CHANNEL_MGMT_H_ */