/*
 * 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>
 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include "osd.h"
#include "logging.h"
#include "VmbusPrivate.h"

/* Internal routines */
static int VmbusChannelCreateGpadlHeader(
        void *Kbuffer,  /* must be phys and virt contiguous */
        u32 Size,       /* page-size multiple */
        struct vmbus_channel_msginfo **msgInfo,
        u32 *MessageCount);
static void DumpVmbusChannel(struct vmbus_channel *channel);
static void VmbusChannelSetEvent(struct vmbus_channel *channel);


#if 0
static void DumpMonitorPage(struct hv_monitor_page *MonitorPage)
{
        int i = 0;
        int j = 0;

        DPRINT_DBG(VMBUS, "monitorPage - %p, trigger state - %d",
                   MonitorPage, MonitorPage->TriggerState);

        for (i = 0; i < 4; i++)
                DPRINT_DBG(VMBUS, "trigger group (%d) - %llx", i,
                           MonitorPage->TriggerGroup[i].AsUINT64);

        for (i = 0; i < 4; i++) {
                for (j = 0; j < 32; j++) {
                        DPRINT_DBG(VMBUS, "latency (%d)(%d) - %llx", i, j,
                                   MonitorPage->Latency[i][j]);
                }
        }
        for (i = 0; i < 4; i++) {
                for (j = 0; j < 32; j++) {
                        DPRINT_DBG(VMBUS, "param-conn id (%d)(%d) - %d", i, j,
                               MonitorPage->Parameter[i][j].ConnectionId.Asu32);
                        DPRINT_DBG(VMBUS, "param-flag (%d)(%d) - %d", i, j,
                                MonitorPage->Parameter[i][j].FlagNumber);
                }
        }
}
#endif

/**
 * VmbusChannelSetEvent - Trigger an event notification on the specified channel.
 */
static void VmbusChannelSetEvent(struct vmbus_channel *Channel)
{
        struct hv_monitor_page *monitorPage;

        DPRINT_ENTER(VMBUS);

        if (Channel->OfferMsg.MonitorAllocated) {
                /* Each u32 represents 32 channels */
                set_bit(Channel->OfferMsg.ChildRelId & 31,
                        (unsigned long *) gVmbusConnection.SendInterruptPage +
                        (Channel->OfferMsg.ChildRelId >> 5));

                monitorPage = gVmbusConnection.MonitorPages;
                monitorPage++; /* Get the child to parent monitor page */

                set_bit(Channel->MonitorBit,
                        (unsigned long *)&monitorPage->TriggerGroup
                                        [Channel->MonitorGroup].Pending);

        } else {
                VmbusSetEvent(Channel->OfferMsg.ChildRelId);
        }

        DPRINT_EXIT(VMBUS);
}

#if 0
static void VmbusChannelClearEvent(struct vmbus_channel *channel)
{
        struct hv_monitor_page *monitorPage;

        DPRINT_ENTER(VMBUS);

        if (Channel->OfferMsg.MonitorAllocated) {
                /* Each u32 represents 32 channels */
                clear_bit(Channel->OfferMsg.ChildRelId & 31,
                          (unsigned long *)gVmbusConnection.SendInterruptPage +
                          (Channel->OfferMsg.ChildRelId >> 5));

                monitorPage =
                        (struct hv_monitor_page *)gVmbusConnection.MonitorPages;
                monitorPage++; /* Get the child to parent monitor page */

                clear_bit(Channel->MonitorBit,
                          (unsigned long *)&monitorPage->TriggerGroup
                                        [Channel->MonitorGroup].Pending);
        }

        DPRINT_EXIT(VMBUS);
}

#endif
/**
 * VmbusChannelGetDebugInfo -Retrieve various channel debug info
 */
void VmbusChannelGetDebugInfo(struct vmbus_channel *Channel,
                              struct vmbus_channel_debug_info *DebugInfo)
{
        struct hv_monitor_page *monitorPage;
        u8 monitorGroup = (u8)Channel->OfferMsg.MonitorId / 32;
        u8 monitorOffset = (u8)Channel->OfferMsg.MonitorId % 32;
        /* u32 monitorBit       = 1 << monitorOffset; */

        DebugInfo->RelId = Channel->OfferMsg.ChildRelId;
        DebugInfo->State = Channel->State;
        memcpy(&DebugInfo->InterfaceType,
               &Channel->OfferMsg.Offer.InterfaceType, sizeof(struct hv_guid));
        memcpy(&DebugInfo->InterfaceInstance,
               &Channel->OfferMsg.Offer.InterfaceInstance,
               sizeof(struct hv_guid));

        monitorPage = (struct hv_monitor_page *)gVmbusConnection.MonitorPages;

        DebugInfo->MonitorId = Channel->OfferMsg.MonitorId;

        DebugInfo->ServerMonitorPending =
                        monitorPage->TriggerGroup[monitorGroup].Pending;
        DebugInfo->ServerMonitorLatency =
                        monitorPage->Latency[monitorGroup][monitorOffset];
        DebugInfo->ServerMonitorConnectionId =
                        monitorPage->Parameter[monitorGroup]
                                              [monitorOffset].ConnectionId.u.Id;

        monitorPage++;

        DebugInfo->ClientMonitorPending =
                        monitorPage->TriggerGroup[monitorGroup].Pending;
        DebugInfo->ClientMonitorLatency =
                        monitorPage->Latency[monitorGroup][monitorOffset];
        DebugInfo->ClientMonitorConnectionId =
                        monitorPage->Parameter[monitorGroup]
                                              [monitorOffset].ConnectionId.u.Id;

        RingBufferGetDebugInfo(&Channel->Inbound, &DebugInfo->Inbound);
        RingBufferGetDebugInfo(&Channel->Outbound, &DebugInfo->Outbound);
}

/**
 * VmbusChannelOpen - Open the specified channel.
 */
int VmbusChannelOpen(struct vmbus_channel *NewChannel, u32 SendRingBufferSize,
                     u32 RecvRingBufferSize, void *UserData, u32 UserDataLen,
                     void (*OnChannelCallback)(void *context), void *Context)
{
        struct vmbus_channel_open_channel *openMsg;
        struct vmbus_channel_msginfo *openInfo;
        void *in, *out;
        unsigned long flags;
        int ret;

        DPRINT_ENTER(VMBUS);

        /* Aligned to page size */
        ASSERT(!(SendRingBufferSize & (PAGE_SIZE - 1)));
        ASSERT(!(RecvRingBufferSize & (PAGE_SIZE - 1)));

        NewChannel->OnChannelCallback = OnChannelCallback;
        NewChannel->ChannelCallbackContext = Context;

        /* Allocate the ring buffer */
        out = osd_PageAlloc((SendRingBufferSize + RecvRingBufferSize)
                             >> PAGE_SHIFT);
        ASSERT(out);
        ASSERT(((unsigned long)out & (PAGE_SIZE-1)) == 0);

        in = (void *)((unsigned long)out + SendRingBufferSize);

        NewChannel->RingBufferPages = out;
        NewChannel->RingBufferPageCount = (SendRingBufferSize +
                                           RecvRingBufferSize) >> PAGE_SHIFT;

        RingBufferInit(&NewChannel->Outbound, out, SendRingBufferSize);

        RingBufferInit(&NewChannel->Inbound, in, RecvRingBufferSize);

        /* Establish the gpadl for the ring buffer */
        DPRINT_DBG(VMBUS, "Establishing ring buffer's gpadl for channel %p...",
                   NewChannel);

        NewChannel->RingBufferGpadlHandle = 0;

        ret = VmbusChannelEstablishGpadl(NewChannel,
                                         NewChannel->Outbound.RingBuffer,
                                         SendRingBufferSize +
                                         RecvRingBufferSize,
                                         &NewChannel->RingBufferGpadlHandle);

        DPRINT_DBG(VMBUS, "channel %p <relid %d gpadl 0x%x send ring %p "
                   "size %d recv ring %p size %d, downstreamoffset %d>",
                   NewChannel, NewChannel->OfferMsg.ChildRelId,
                   NewChannel->RingBufferGpadlHandle,
                   NewChannel->Outbound.RingBuffer,
                   NewChannel->Outbound.RingSize,
                   NewChannel->Inbound.RingBuffer,
                   NewChannel->Inbound.RingSize,
                   SendRingBufferSize);

        /* Create and init the channel open message */
        openInfo = kmalloc(sizeof(*openInfo) +
                           sizeof(struct vmbus_channel_open_channel),
                           GFP_KERNEL);
        ASSERT(openInfo != NULL);

        openInfo->WaitEvent = osd_WaitEventCreate();

        openMsg = (struct vmbus_channel_open_channel *)openInfo->Msg;
        openMsg->Header.MessageType = ChannelMessageOpenChannel;
        openMsg->OpenId = NewChannel->OfferMsg.ChildRelId; /* FIXME */
        openMsg->ChildRelId = NewChannel->OfferMsg.ChildRelId;
        openMsg->RingBufferGpadlHandle = NewChannel->RingBufferGpadlHandle;
        ASSERT(openMsg->RingBufferGpadlHandle);
        openMsg->DownstreamRingBufferPageOffset = SendRingBufferSize >>
                                                  PAGE_SHIFT;
        openMsg->ServerContextAreaGpadlHandle = 0; /* TODO */

        ASSERT(UserDataLen <= MAX_USER_DEFINED_BYTES);
        if (UserDataLen)
                memcpy(openMsg->UserData, UserData, UserDataLen);

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&openInfo->MsgListEntry,
                      &gVmbusConnection.ChannelMsgList);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        DPRINT_DBG(VMBUS, "Sending channel open msg...");

        ret = VmbusPostMessage(openMsg,
                               sizeof(struct vmbus_channel_open_channel));
        if (ret != 0) {
                DPRINT_ERR(VMBUS, "unable to open channel - %d", ret);
                goto Cleanup;
        }

        /* FIXME: Need to time-out here */
        osd_WaitEventWait(openInfo->WaitEvent);

        if (openInfo->Response.OpenResult.Status == 0)
                DPRINT_INFO(VMBUS, "channel <%p> open success!!", NewChannel);
        else
                DPRINT_INFO(VMBUS, "channel <%p> open failed - %d!!",
                            NewChannel, openInfo->Response.OpenResult.Status);

Cleanup:
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&openInfo->MsgListEntry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(openInfo->WaitEvent);
        kfree(openInfo);

        DPRINT_EXIT(VMBUS);

        return 0;
}

/**
 * DumpGpadlBody - Dump the gpadl body message to the console for debugging purposes.
 */
static void DumpGpadlBody(struct vmbus_channel_gpadl_body *Gpadl, u32 Len)
{
        int i;
        int pfnCount;

        pfnCount = (Len - sizeof(struct vmbus_channel_gpadl_body)) /
                   sizeof(u64);
        DPRINT_DBG(VMBUS, "gpadl body - len %d pfn count %d", Len, pfnCount);

        for (i = 0; i < pfnCount; i++)
                DPRINT_DBG(VMBUS, "gpadl body  - %d) pfn %llu",
                           i, Gpadl->Pfn[i]);
}

/**
 * DumpGpadlHeader - Dump the gpadl header message to the console for debugging purposes.
 */
static void DumpGpadlHeader(struct vmbus_channel_gpadl_header *Gpadl)
{
        int i, j;
        int pageCount;

        DPRINT_DBG(VMBUS,
                   "gpadl header - relid %d, range count %d, range buflen %d",
                   Gpadl->ChildRelId, Gpadl->RangeCount, Gpadl->RangeBufLen);
        for (i = 0; i < Gpadl->RangeCount; i++) {
                pageCount = Gpadl->Range[i].ByteCount >> PAGE_SHIFT;
                pageCount = (pageCount > 26) ? 26 : pageCount;

                DPRINT_DBG(VMBUS, "gpadl range %d - len %d offset %d "
                           "page count %d", i, Gpadl->Range[i].ByteCount,
                           Gpadl->Range[i].ByteOffset, pageCount);

                for (j = 0; j < pageCount; j++)
                        DPRINT_DBG(VMBUS, "%d) pfn %llu", j,
                                   Gpadl->Range[i].PfnArray[j]);
        }
}

/**
 * VmbusChannelCreateGpadlHeader - Creates a gpadl for the specified buffer
 */
static int VmbusChannelCreateGpadlHeader(void *Kbuffer, u32 Size,
                                         struct vmbus_channel_msginfo **MsgInfo,
                                         u32 *MessageCount)
{
        int i;
        int pageCount;
        unsigned long long pfn;
        struct vmbus_channel_gpadl_header *gpaHeader;
        struct vmbus_channel_gpadl_body *gpadlBody;
        struct vmbus_channel_msginfo *msgHeader;
        struct vmbus_channel_msginfo *msgBody;
        u32 msgSize;

        int pfnSum, pfnCount, pfnLeft, pfnCurr, pfnSize;

        /* ASSERT((kbuffer & (PAGE_SIZE-1)) == 0); */
        ASSERT((Size & (PAGE_SIZE-1)) == 0);

        pageCount = Size >> PAGE_SHIFT;
        pfn = virt_to_phys(Kbuffer) >> PAGE_SHIFT;

        /* do we need a gpadl body msg */
        pfnSize = MAX_SIZE_CHANNEL_MESSAGE -
                  sizeof(struct vmbus_channel_gpadl_header) -
                  sizeof(struct gpa_range);
        pfnCount = pfnSize / sizeof(u64);

        if (pageCount > pfnCount) {
                /* we need a gpadl body */
                /* fill in the header */
                msgSize = sizeof(struct vmbus_channel_msginfo) +
                          sizeof(struct vmbus_channel_gpadl_header) +
                          sizeof(struct gpa_range) + pfnCount * sizeof(u64);
                msgHeader =  kzalloc(msgSize, GFP_KERNEL);

                INIT_LIST_HEAD(&msgHeader->SubMsgList);
                msgHeader->MessageSize = msgSize;

                gpaHeader = (struct vmbus_channel_gpadl_header *)msgHeader->Msg;
                gpaHeader->RangeCount = 1;
                gpaHeader->RangeBufLen = sizeof(struct gpa_range) +
                                         pageCount * sizeof(u64);
                gpaHeader->Range[0].ByteOffset = 0;
                gpaHeader->Range[0].ByteCount = Size;
                for (i = 0; i < pfnCount; i++)
                        gpaHeader->Range[0].PfnArray[i] = pfn+i;
                *MsgInfo = msgHeader;
                *MessageCount = 1;

                pfnSum = pfnCount;
                pfnLeft = pageCount - pfnCount;

                /* how many pfns can we fit */
                pfnSize = MAX_SIZE_CHANNEL_MESSAGE -
                          sizeof(struct vmbus_channel_gpadl_body);
                pfnCount = pfnSize / sizeof(u64);

                /* fill in the body */
                while (pfnLeft) {
                        if (pfnLeft > pfnCount)
                                pfnCurr = pfnCount;
                        else
                                pfnCurr = pfnLeft;

                        msgSize = sizeof(struct vmbus_channel_msginfo) +
                                  sizeof(struct vmbus_channel_gpadl_body) +
                                  pfnCurr * sizeof(u64);
                        msgBody = kzalloc(msgSize, GFP_KERNEL);
                        ASSERT(msgBody);
                        msgBody->MessageSize = msgSize;
                        (*MessageCount)++;
                        gpadlBody =
                                (struct vmbus_channel_gpadl_body *)msgBody->Msg;

                        /*
                         * FIXME:
                         * Gpadl is u32 and we are using a pointer which could
                         * be 64-bit
                         */
                        /* gpadlBody->Gpadl = kbuffer; */
                        for (i = 0; i < pfnCurr; i++)
                                gpadlBody->Pfn[i] = pfn + pfnSum + i;

                        /* add to msg header */
                        list_add_tail(&msgBody->MsgListEntry,
                                      &msgHeader->SubMsgList);
                        pfnSum += pfnCurr;
                        pfnLeft -= pfnCurr;
                }
        } else {
                /* everything fits in a header */
                msgSize = sizeof(struct vmbus_channel_msginfo) +
                          sizeof(struct vmbus_channel_gpadl_header) +
                          sizeof(struct gpa_range) + pageCount * sizeof(u64);
                msgHeader = kzalloc(msgSize, GFP_KERNEL);
                msgHeader->MessageSize = msgSize;

                gpaHeader = (struct vmbus_channel_gpadl_header *)msgHeader->Msg;
                gpaHeader->RangeCount = 1;
                gpaHeader->RangeBufLen = sizeof(struct gpa_range) +
                                         pageCount * sizeof(u64);
                gpaHeader->Range[0].ByteOffset = 0;
                gpaHeader->Range[0].ByteCount = Size;
                for (i = 0; i < pageCount; i++)
                        gpaHeader->Range[0].PfnArray[i] = pfn+i;

                *MsgInfo = msgHeader;
                *MessageCount = 1;
        }

        return 0;
}

/**
 * VmbusChannelEstablishGpadl - Estabish a GPADL for the specified buffer
 *
 * @Channel: a channel
 * @Kbuffer: from kmalloc
 * @Size: page-size multiple
 * @GpadlHandle: some funky thing
 */
int VmbusChannelEstablishGpadl(struct vmbus_channel *Channel, void *Kbuffer,
                               u32 Size, u32 *GpadlHandle)
{
        struct vmbus_channel_gpadl_header *gpadlMsg;
        struct vmbus_channel_gpadl_body *gpadlBody;
        /* struct vmbus_channel_gpadl_created *gpadlCreated; */
        struct vmbus_channel_msginfo *msgInfo;
        struct vmbus_channel_msginfo *subMsgInfo;
        u32 msgCount;
        struct list_head *curr;
        u32 nextGpadlHandle;
        unsigned long flags;
        int ret;

        DPRINT_ENTER(VMBUS);

        nextGpadlHandle = atomic_read(&gVmbusConnection.NextGpadlHandle);
        atomic_inc(&gVmbusConnection.NextGpadlHandle);

        VmbusChannelCreateGpadlHeader(Kbuffer, Size, &msgInfo, &msgCount);
        ASSERT(msgInfo != NULL);
        ASSERT(msgCount > 0);

        msgInfo->WaitEvent = osd_WaitEventCreate();
        gpadlMsg = (struct vmbus_channel_gpadl_header *)msgInfo->Msg;
        gpadlMsg->Header.MessageType = ChannelMessageGpadlHeader;
        gpadlMsg->ChildRelId = Channel->OfferMsg.ChildRelId;
        gpadlMsg->Gpadl = nextGpadlHandle;

        DumpGpadlHeader(gpadlMsg);

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&msgInfo->MsgListEntry,
                      &gVmbusConnection.ChannelMsgList);

        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);
        DPRINT_DBG(VMBUS, "buffer %p, size %d msg cnt %d",
                   Kbuffer, Size, msgCount);

        DPRINT_DBG(VMBUS, "Sending GPADL Header - len %zd",
                   msgInfo->MessageSize - sizeof(*msgInfo));

        ret = VmbusPostMessage(gpadlMsg, msgInfo->MessageSize -
                               sizeof(*msgInfo));
        if (ret != 0) {
                DPRINT_ERR(VMBUS, "Unable to open channel - %d", ret);
                goto Cleanup;
        }

        if (msgCount > 1) {
                list_for_each(curr, &msgInfo->SubMsgList) {

                        /* FIXME: should this use list_entry() instead ? */
                        subMsgInfo = (struct vmbus_channel_msginfo *)curr;
                        gpadlBody =
                             (struct vmbus_channel_gpadl_body *)subMsgInfo->Msg;

                        gpadlBody->Header.MessageType = ChannelMessageGpadlBody;
                        gpadlBody->Gpadl = nextGpadlHandle;

                        DPRINT_DBG(VMBUS, "Sending GPADL Body - len %zd",
                                   subMsgInfo->MessageSize -
                                   sizeof(*subMsgInfo));

                        DumpGpadlBody(gpadlBody, subMsgInfo->MessageSize -
                                      sizeof(*subMsgInfo));
                        ret = VmbusPostMessage(gpadlBody,
                                               subMsgInfo->MessageSize -
                                               sizeof(*subMsgInfo));
                        ASSERT(ret == 0);
                }
        }
        osd_WaitEventWait(msgInfo->WaitEvent);

        /* At this point, we received the gpadl created msg */
        DPRINT_DBG(VMBUS, "Received GPADL created "
                   "(relid %d, status %d handle %x)",
                   Channel->OfferMsg.ChildRelId,
                   msgInfo->Response.GpadlCreated.CreationStatus,
                   gpadlMsg->Gpadl);

        *GpadlHandle = gpadlMsg->Gpadl;

Cleanup:
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&msgInfo->MsgListEntry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(msgInfo->WaitEvent);
        kfree(msgInfo);

        DPRINT_EXIT(VMBUS);

        return ret;
}

/**
 * VmbusChannelTeardownGpadl -Teardown the specified GPADL handle
 */
int VmbusChannelTeardownGpadl(struct vmbus_channel *Channel, u32 GpadlHandle)
{
        struct vmbus_channel_gpadl_teardown *msg;
        struct vmbus_channel_msginfo *info;
        unsigned long flags;
        int ret;

        DPRINT_ENTER(VMBUS);

        ASSERT(GpadlHandle != 0);

        info = kmalloc(sizeof(*info) +
                       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
        ASSERT(info != NULL);

        info->WaitEvent = osd_WaitEventCreate();

        msg = (struct vmbus_channel_gpadl_teardown *)info->Msg;

        msg->Header.MessageType = ChannelMessageGpadlTeardown;
        msg->ChildRelId = Channel->OfferMsg.ChildRelId;
        msg->Gpadl = GpadlHandle;

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&info->MsgListEntry,
                      &gVmbusConnection.ChannelMsgList);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        ret = VmbusPostMessage(msg,
                               sizeof(struct vmbus_channel_gpadl_teardown));
        if (ret != 0) {
                /* TODO: */
                /* something... */
        }

        osd_WaitEventWait(info->WaitEvent);

        /* Received a torndown response */
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&info->MsgListEntry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(info->WaitEvent);
        kfree(info);

        DPRINT_EXIT(VMBUS);

        return ret;
}

/**
 * VmbusChannelClose - Close the specified channel
 */
void VmbusChannelClose(struct vmbus_channel *Channel)
{
        struct vmbus_channel_close_channel *msg;
        struct vmbus_channel_msginfo *info;
        unsigned long flags;
        int ret;

        DPRINT_ENTER(VMBUS);

        /* Stop callback and cancel the timer asap */
        Channel->OnChannelCallback = NULL;
        del_timer_sync(&Channel->poll_timer);

        /* Send a closing message */
        info = kmalloc(sizeof(*info) +
                       sizeof(struct vmbus_channel_close_channel), GFP_KERNEL);
        ASSERT(info != NULL);

        /* info->waitEvent = osd_WaitEventCreate(); */

        msg = (struct vmbus_channel_close_channel *)info->Msg;
        msg->Header.MessageType = ChannelMessageCloseChannel;
        msg->ChildRelId = Channel->OfferMsg.ChildRelId;

        ret = VmbusPostMessage(msg, sizeof(struct vmbus_channel_close_channel));
        if (ret != 0) {
                /* TODO: */
                /* something... */
        }

        /* Tear down the gpadl for the channel's ring buffer */
        if (Channel->RingBufferGpadlHandle)
                VmbusChannelTeardownGpadl(Channel,
                                          Channel->RingBufferGpadlHandle);

        /* TODO: Send a msg to release the childRelId */

        /* Cleanup the ring buffers for this channel */
        RingBufferCleanup(&Channel->Outbound);
        RingBufferCleanup(&Channel->Inbound);

        osd_PageFree(Channel->RingBufferPages, Channel->RingBufferPageCount);

        kfree(info);

        /*
         * If we are closing the channel during an error path in
         * opening the channel, don't free the channel since the
         * caller will free the channel
         */

        if (Channel->State == CHANNEL_OPEN_STATE) {
                spin_lock_irqsave(&gVmbusConnection.channel_lock, flags);
                list_del(&Channel->ListEntry);
                spin_unlock_irqrestore(&gVmbusConnection.channel_lock, flags);

                FreeVmbusChannel(Channel);
        }

        DPRINT_EXIT(VMBUS);
}

/**
 * VmbusChannelSendPacket - Send the specified buffer on the given channel
 */
int VmbusChannelSendPacket(struct vmbus_channel *Channel, const void *Buffer,
                           u32 BufferLen, u64 RequestId,
                           enum vmbus_packet_type Type, u32 Flags)
{
        struct vmpacket_descriptor desc;
        u32 packetLen = sizeof(struct vmpacket_descriptor) + BufferLen;
        u32 packetLenAligned = ALIGN_UP(packetLen, sizeof(u64));
        struct scatterlist bufferList[3];
        u64 alignedData = 0;
        int ret;

        DPRINT_ENTER(VMBUS);
        DPRINT_DBG(VMBUS, "channel %p buffer %p len %d",
                   Channel, Buffer, BufferLen);

        DumpVmbusChannel(Channel);

        ASSERT((packetLenAligned - packetLen) < sizeof(u64));

        /* Setup the descriptor */
        desc.Type = Type; /* VmbusPacketTypeDataInBand; */
        desc.Flags = Flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
        /* in 8-bytes granularity */
        desc.DataOffset8 = sizeof(struct vmpacket_descriptor) >> 3;
        desc.Length8 = (u16)(packetLenAligned >> 3);
        desc.TransactionId = RequestId;

        sg_init_table(bufferList, 3);
        sg_set_buf(&bufferList[0], &desc, sizeof(struct vmpacket_descriptor));
        sg_set_buf(&bufferList[1], Buffer, BufferLen);
        sg_set_buf(&bufferList[2], &alignedData, packetLenAligned - packetLen);

        ret = RingBufferWrite(&Channel->Outbound, bufferList, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !GetRingBufferInterruptMask(&Channel->Outbound))
                VmbusChannelSetEvent(Channel);

        DPRINT_EXIT(VMBUS);

        return ret;
}

/**
 * VmbusChannelSendPacketPageBuffer - Send a range of single-page buffer packets using a GPADL Direct packet type.
 */
int VmbusChannelSendPacketPageBuffer(struct vmbus_channel *Channel,
                                     struct hv_page_buffer PageBuffers[],
                                     u32 PageCount, void *Buffer, u32 BufferLen,
                                     u64 RequestId)
{
        int ret;
        int i;
        struct VMBUS_CHANNEL_PACKET_PAGE_BUFFER desc;
        u32 descSize;
        u32 packetLen;
        u32 packetLenAligned;
        struct scatterlist bufferList[3];
        u64 alignedData = 0;

        DPRINT_ENTER(VMBUS);

        ASSERT(PageCount <= MAX_PAGE_BUFFER_COUNT);

        DumpVmbusChannel(Channel);

        /*
         * Adjust the size down since VMBUS_CHANNEL_PACKET_PAGE_BUFFER is the
         * largest size we support
         */
        descSize = sizeof(struct VMBUS_CHANNEL_PACKET_PAGE_BUFFER) -
                          ((MAX_PAGE_BUFFER_COUNT - PageCount) *
                          sizeof(struct hv_page_buffer));
        packetLen = descSize + BufferLen;
        packetLenAligned = ALIGN_UP(packetLen, sizeof(u64));

        ASSERT((packetLenAligned - packetLen) < sizeof(u64));

        /* Setup the descriptor */
        desc.Type = VmbusPacketTypeDataUsingGpaDirect;
        desc.Flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
        desc.DataOffset8 = descSize >> 3; /* in 8-bytes grandularity */
        desc.Length8 = (u16)(packetLenAligned >> 3);
        desc.TransactionId = RequestId;
        desc.RangeCount = PageCount;

        for (i = 0; i < PageCount; i++) {
                desc.Range[i].Length = PageBuffers[i].Length;
                desc.Range[i].Offset = PageBuffers[i].Offset;
                desc.Range[i].Pfn        = PageBuffers[i].Pfn;
        }

        sg_init_table(bufferList, 3);
        sg_set_buf(&bufferList[0], &desc, descSize);
        sg_set_buf(&bufferList[1], Buffer, BufferLen);
        sg_set_buf(&bufferList[2], &alignedData, packetLenAligned - packetLen);

        ret = RingBufferWrite(&Channel->Outbound, bufferList, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !GetRingBufferInterruptMask(&Channel->Outbound))
                VmbusChannelSetEvent(Channel);

        DPRINT_EXIT(VMBUS);

        return ret;
}

/**
 * VmbusChannelSendPacketMultiPageBuffer - Send a multi-page buffer packet using a GPADL Direct packet type.
 */
int VmbusChannelSendPacketMultiPageBuffer(struct vmbus_channel *Channel,
                                struct hv_multipage_buffer *MultiPageBuffer,
                                void *Buffer, u32 BufferLen, u64 RequestId)
{
        int ret;
        struct VMBUS_CHANNEL_PACKET_MULITPAGE_BUFFER desc;
        u32 descSize;
        u32 packetLen;
        u32 packetLenAligned;
        struct scatterlist bufferList[3];
        u64 alignedData = 0;
        u32 PfnCount = NUM_PAGES_SPANNED(MultiPageBuffer->Offset,
                                         MultiPageBuffer->Length);

        DPRINT_ENTER(VMBUS);

        DumpVmbusChannel(Channel);

        DPRINT_DBG(VMBUS, "data buffer - offset %u len %u pfn count %u",
                   MultiPageBuffer->Offset, MultiPageBuffer->Length, PfnCount);

        ASSERT(PfnCount > 0);
        ASSERT(PfnCount <= MAX_MULTIPAGE_BUFFER_COUNT);

        /*
         * Adjust the size down since VMBUS_CHANNEL_PACKET_MULITPAGE_BUFFER is
         * the largest size we support
         */
        descSize = sizeof(struct VMBUS_CHANNEL_PACKET_MULITPAGE_BUFFER) -
                          ((MAX_MULTIPAGE_BUFFER_COUNT - PfnCount) *
                          sizeof(u64));
        packetLen = descSize + BufferLen;
        packetLenAligned = ALIGN_UP(packetLen, sizeof(u64));

        ASSERT((packetLenAligned - packetLen) < sizeof(u64));

        /* Setup the descriptor */
        desc.Type = VmbusPacketTypeDataUsingGpaDirect;
        desc.Flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
        desc.DataOffset8 = descSize >> 3; /* in 8-bytes grandularity */
        desc.Length8 = (u16)(packetLenAligned >> 3);
        desc.TransactionId = RequestId;
        desc.RangeCount = 1;

        desc.Range.Length = MultiPageBuffer->Length;
        desc.Range.Offset = MultiPageBuffer->Offset;

        memcpy(desc.Range.PfnArray, MultiPageBuffer->PfnArray,
               PfnCount * sizeof(u64));

        sg_init_table(bufferList, 3);
        sg_set_buf(&bufferList[0], &desc, descSize);
        sg_set_buf(&bufferList[1], Buffer, BufferLen);
        sg_set_buf(&bufferList[2], &alignedData, packetLenAligned - packetLen);

        ret = RingBufferWrite(&Channel->Outbound, bufferList, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !GetRingBufferInterruptMask(&Channel->Outbound))
                VmbusChannelSetEvent(Channel);

        DPRINT_EXIT(VMBUS);

        return ret;
}

/**
 * VmbusChannelRecvPacket - Retrieve the user packet on the specified channel
 */
/* TODO: Do we ever receive a gpa direct packet other than the ones we send ? */
int VmbusChannelRecvPacket(struct vmbus_channel *Channel, void *Buffer,
                           u32 BufferLen, u32 *BufferActualLen, u64 *RequestId)
{
        struct vmpacket_descriptor desc;
        u32 packetLen;
        u32 userLen;
        int ret;
        unsigned long flags;

        DPRINT_ENTER(VMBUS);

        *BufferActualLen = 0;
        *RequestId = 0;

        spin_lock_irqsave(&Channel->inbound_lock, flags);

        ret = RingBufferPeek(&Channel->Inbound, &desc,
                             sizeof(struct vmpacket_descriptor));
        if (ret != 0) {
                spin_unlock_irqrestore(&Channel->inbound_lock, flags);

                /* DPRINT_DBG(VMBUS, "nothing to read!!"); */
                DPRINT_EXIT(VMBUS);
                return 0;
        }

        /* VmbusChannelClearEvent(Channel); */

        packetLen = desc.Length8 << 3;
        userLen = packetLen - (desc.DataOffset8 << 3);
        /* ASSERT(userLen > 0); */

        DPRINT_DBG(VMBUS, "packet received on channel %p relid %d <type %d "
                   "flag %d tid %llx pktlen %d datalen %d> ",
                   Channel, Channel->OfferMsg.ChildRelId, desc.Type,
                   desc.Flags, desc.TransactionId, packetLen, userLen);

        *BufferActualLen = userLen;

        if (userLen > BufferLen) {
                spin_unlock_irqrestore(&Channel->inbound_lock, flags);

                DPRINT_ERR(VMBUS, "buffer too small - got %d needs %d",
                           BufferLen, userLen);
                DPRINT_EXIT(VMBUS);

                return -1;
        }

        *RequestId = desc.TransactionId;

        /* Copy over the packet to the user buffer */
        ret = RingBufferRead(&Channel->Inbound, Buffer, userLen,
                             (desc.DataOffset8 << 3));

        spin_unlock_irqrestore(&Channel->inbound_lock, flags);

        DPRINT_EXIT(VMBUS);

        return 0;
}

/**
 * VmbusChannelRecvPacketRaw - Retrieve the raw packet on the specified channel
 */
int VmbusChannelRecvPacketRaw(struct vmbus_channel *Channel, void *Buffer,
                              u32 BufferLen, u32 *BufferActualLen,
                              u64 *RequestId)
{
        struct vmpacket_descriptor desc;
        u32 packetLen;
        u32 userLen;
        int ret;
        unsigned long flags;

        DPRINT_ENTER(VMBUS);

        *BufferActualLen = 0;
        *RequestId = 0;

        spin_lock_irqsave(&Channel->inbound_lock, flags);

        ret = RingBufferPeek(&Channel->Inbound, &desc,
                             sizeof(struct vmpacket_descriptor));
        if (ret != 0) {
                spin_unlock_irqrestore(&Channel->inbound_lock, flags);

                /* DPRINT_DBG(VMBUS, "nothing to read!!"); */
                DPRINT_EXIT(VMBUS);
                return 0;
        }

        /* VmbusChannelClearEvent(Channel); */

        packetLen = desc.Length8 << 3;
        userLen = packetLen - (desc.DataOffset8 << 3);

        DPRINT_DBG(VMBUS, "packet received on channel %p relid %d <type %d "
                   "flag %d tid %llx pktlen %d datalen %d> ",
                   Channel, Channel->OfferMsg.ChildRelId, desc.Type,
                   desc.Flags, desc.TransactionId, packetLen, userLen);

        *BufferActualLen = packetLen;

        if (packetLen > BufferLen) {
                spin_unlock_irqrestore(&Channel->inbound_lock, flags);

                DPRINT_ERR(VMBUS, "buffer too small - needed %d bytes but "
                           "got space for only %d bytes", packetLen, BufferLen);
                DPRINT_EXIT(VMBUS);
                return -2;
        }

        *RequestId = desc.TransactionId;

        /* Copy over the entire packet to the user buffer */
        ret = RingBufferRead(&Channel->Inbound, Buffer, packetLen, 0);

        spin_unlock_irqrestore(&Channel->inbound_lock, flags);

        DPRINT_EXIT(VMBUS);

        return 0;
}

/**
 * VmbusChannelOnChannelEvent - Channel event callback
 */
void VmbusChannelOnChannelEvent(struct vmbus_channel *Channel)
{
        DumpVmbusChannel(Channel);
        ASSERT(Channel->OnChannelCallback);

        Channel->OnChannelCallback(Channel->ChannelCallbackContext);

        mod_timer(&Channel->poll_timer, jiffies + usecs_to_jiffies(100));
}

/**
 * VmbusChannelOnTimer - Timer event callback
 */
void VmbusChannelOnTimer(unsigned long data)
{
        struct vmbus_channel *channel = (struct vmbus_channel *)data;

        if (channel->OnChannelCallback) {
                channel->OnChannelCallback(channel->ChannelCallbackContext);
        }
}

/**
 * DumpVmbusChannel - Dump vmbus channel info to the console

 */
static void DumpVmbusChannel(struct vmbus_channel *Channel)
{
        DPRINT_DBG(VMBUS, "Channel (%d)", Channel->OfferMsg.ChildRelId);
        DumpRingInfo(&Channel->Outbound, "Outbound ");
        DumpRingInfo(&Channel->Inbound, "Inbound ");
}