Staging: hv: add the Hyper-V virtual bus
This is the virtual bus that all of the Linux Hyper-V drivers use.
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/hv/RingBuffer.c b/drivers/staging/hv/RingBuffer.c
new file mode 100644
index 0000000..57d944e
--- /dev/null
+++ b/drivers/staging/hv/RingBuffer.c
@@ -0,0 +1,630 @@
+/*
+ *
+ * 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 "logging.h"
+#include "RingBuffer.h"
+
+//
+// #defines
+//
+
+// Amount of space to write to
+#define BYTES_AVAIL_TO_WRITE(r, w, z) ((w) >= (r))?((z) - ((w) - (r))):((r) - (w))
+
+
+/*++
+
+Name:
+ GetRingBufferAvailBytes()
+
+Description:
+ Get number of bytes available to read and to write to
+ for the specified ring buffer
+
+--*/
+static inline void
+GetRingBufferAvailBytes(RING_BUFFER_INFO *rbi, UINT32 *read, UINT32 *write)
+{
+ UINT32 read_loc,write_loc;
+
+ // Capture the read/write indices before they changed
+ read_loc = rbi->RingBuffer->ReadIndex;
+ write_loc = rbi->RingBuffer->WriteIndex;
+
+ *write = BYTES_AVAIL_TO_WRITE(read_loc, write_loc, rbi->RingDataSize);
+ *read = rbi->RingDataSize - *write;
+}
+
+/*++
+
+Name:
+ GetNextWriteLocation()
+
+Description:
+ Get the next write location for the specified ring buffer
+
+--*/
+static inline UINT32
+GetNextWriteLocation(RING_BUFFER_INFO* RingInfo)
+{
+ UINT32 next = RingInfo->RingBuffer->WriteIndex;
+
+ ASSERT(next < RingInfo->RingDataSize);
+
+ return next;
+}
+
+/*++
+
+Name:
+ SetNextWriteLocation()
+
+Description:
+ Set the next write location for the specified ring buffer
+
+--*/
+static inline void
+SetNextWriteLocation(RING_BUFFER_INFO* RingInfo, UINT32 NextWriteLocation)
+{
+ RingInfo->RingBuffer->WriteIndex = NextWriteLocation;
+}
+
+/*++
+
+Name:
+ GetNextReadLocation()
+
+Description:
+ Get the next read location for the specified ring buffer
+
+--*/
+static inline UINT32
+GetNextReadLocation(RING_BUFFER_INFO* RingInfo)
+{
+ UINT32 next = RingInfo->RingBuffer->ReadIndex;
+
+ ASSERT(next < RingInfo->RingDataSize);
+
+ return next;
+}
+
+/*++
+
+Name:
+ GetNextReadLocationWithOffset()
+
+Description:
+ Get the next read location + offset for the specified ring buffer.
+ This allows the caller to skip
+
+--*/
+static inline UINT32
+GetNextReadLocationWithOffset(RING_BUFFER_INFO* RingInfo, UINT32 Offset)
+{
+ UINT32 next = RingInfo->RingBuffer->ReadIndex;
+
+ ASSERT(next < RingInfo->RingDataSize);
+ next += Offset;
+ next %= RingInfo->RingDataSize;
+
+ return next;
+}
+
+/*++
+
+Name:
+ SetNextReadLocation()
+
+Description:
+ Set the next read location for the specified ring buffer
+
+--*/
+static inline void
+SetNextReadLocation(RING_BUFFER_INFO* RingInfo, UINT32 NextReadLocation)
+{
+ RingInfo->RingBuffer->ReadIndex = NextReadLocation;
+}
+
+
+/*++
+
+Name:
+ GetRingBuffer()
+
+Description:
+ Get the start of the ring buffer
+
+--*/
+static inline PVOID
+GetRingBuffer(RING_BUFFER_INFO* RingInfo)
+{
+ return (PVOID)RingInfo->RingBuffer->Buffer;
+}
+
+
+/*++
+
+Name:
+ GetRingBufferSize()
+
+Description:
+ Get the size of the ring buffer
+
+--*/
+static inline UINT32
+GetRingBufferSize(RING_BUFFER_INFO* RingInfo)
+{
+ return RingInfo->RingDataSize;
+}
+
+/*++
+
+Name:
+ GetRingBufferIndices()
+
+Description:
+ Get the read and write indices as UINT64 of the specified ring buffer
+
+--*/
+static inline UINT64
+GetRingBufferIndices(RING_BUFFER_INFO* RingInfo)
+{
+ return ((UINT64)RingInfo->RingBuffer->WriteIndex << 32) || RingInfo->RingBuffer->ReadIndex;
+}
+
+
+/*++
+
+Name:
+ DumpRingInfo()
+
+Description:
+ Dump out to console the ring buffer info
+
+--*/
+void
+DumpRingInfo(RING_BUFFER_INFO* RingInfo, char *Prefix)
+{
+ UINT32 bytesAvailToWrite;
+ UINT32 bytesAvailToRead;
+
+ GetRingBufferAvailBytes(RingInfo, &bytesAvailToRead, &bytesAvailToWrite);
+
+ DPRINT(VMBUS, DEBUG_RING_LVL, "%s <<ringinfo %p buffer %p avail write %u avail read %u read idx %u write idx %u>>",
+ Prefix,
+ RingInfo,
+ RingInfo->RingBuffer->Buffer,
+ bytesAvailToWrite,
+ bytesAvailToRead,
+ RingInfo->RingBuffer->ReadIndex,
+ RingInfo->RingBuffer->WriteIndex);
+}
+
+//
+// Internal routines
+//
+static UINT32
+CopyToRingBuffer(
+ RING_BUFFER_INFO *RingInfo,
+ UINT32 StartWriteOffset,
+ PVOID Src,
+ UINT32 SrcLen);
+
+static UINT32
+CopyFromRingBuffer(
+ RING_BUFFER_INFO *RingInfo,
+ PVOID Dest,
+ UINT32 DestLen,
+ UINT32 StartReadOffset);
+
+
+
+/*++
+
+Name:
+ RingBufferGetDebugInfo()
+
+Description:
+ Get various debug metrics for the specified ring buffer
+
+--*/
+void
+RingBufferGetDebugInfo(
+ RING_BUFFER_INFO *RingInfo,
+ RING_BUFFER_DEBUG_INFO *DebugInfo
+ )
+{
+ UINT32 bytesAvailToWrite;
+ UINT32 bytesAvailToRead;
+
+ if (RingInfo->RingBuffer)
+ {
+ GetRingBufferAvailBytes(RingInfo, &bytesAvailToRead, &bytesAvailToWrite);
+
+ DebugInfo->BytesAvailToRead = bytesAvailToRead;
+ DebugInfo->BytesAvailToWrite = bytesAvailToWrite;
+ DebugInfo->CurrentReadIndex = RingInfo->RingBuffer->ReadIndex;
+ DebugInfo->CurrentWriteIndex = RingInfo->RingBuffer->WriteIndex;
+
+ DebugInfo->CurrentInterruptMask = RingInfo->RingBuffer->InterruptMask;
+ }
+}
+
+
+/*++
+
+Name:
+ GetRingBufferInterruptMask()
+
+Description:
+ Get the interrupt mask for the specified ring buffer
+
+--*/
+UINT32
+GetRingBufferInterruptMask(
+ RING_BUFFER_INFO *rbi
+ )
+{
+ return rbi->RingBuffer->InterruptMask;
+}
+
+/*++
+
+Name:
+ RingBufferInit()
+
+Description:
+ Initialize the ring buffer
+
+--*/
+int
+RingBufferInit(
+ RING_BUFFER_INFO *RingInfo,
+ VOID *Buffer,
+ UINT32 BufferLen
+ )
+{
+ ASSERT(sizeof(RING_BUFFER) == PAGE_SIZE);
+
+ memset(RingInfo, 0, sizeof(RING_BUFFER_INFO));
+
+ RingInfo->RingBuffer = (RING_BUFFER*)Buffer;
+ RingInfo->RingBuffer->ReadIndex = RingInfo->RingBuffer->WriteIndex = 0;
+
+ RingInfo->RingSize = BufferLen;
+ RingInfo->RingDataSize = BufferLen - sizeof(RING_BUFFER);
+
+ RingInfo->RingLock = SpinlockCreate();
+
+ return 0;
+}
+
+/*++
+
+Name:
+ RingBufferCleanup()
+
+Description:
+ Cleanup the ring buffer
+
+--*/
+void
+RingBufferCleanup(
+ RING_BUFFER_INFO* RingInfo
+ )
+{
+ SpinlockClose(RingInfo->RingLock);
+}
+
+/*++
+
+Name:
+ RingBufferWrite()
+
+Description:
+ Write to the ring buffer
+
+--*/
+int
+RingBufferWrite(
+ RING_BUFFER_INFO* OutRingInfo,
+ SG_BUFFER_LIST SgBuffers[],
+ UINT32 SgBufferCount
+ )
+{
+ int i=0;
+ UINT32 byteAvailToWrite;
+ UINT32 byteAvailToRead;
+ UINT32 totalBytesToWrite=0;
+
+ volatile UINT32 nextWriteLocation;
+ UINT64 prevIndices=0;
+
+ DPRINT_ENTER(VMBUS);
+
+ for (i=0; i < SgBufferCount; i++)
+ {
+ totalBytesToWrite += SgBuffers[i].Length;
+ }
+
+ totalBytesToWrite += sizeof(UINT64);
+
+ SpinlockAcquire(OutRingInfo->RingLock);
+
+ GetRingBufferAvailBytes(OutRingInfo, &byteAvailToRead, &byteAvailToWrite);
+
+ DPRINT_DBG(VMBUS, "Writing %u bytes...", totalBytesToWrite);
+
+ //DumpRingInfo(OutRingInfo, "BEFORE ");
+
+ // If there is only room for the packet, assume it is full. Otherwise, the next time around, we think the ring buffer
+ // is empty since the read index == write index
+ if (byteAvailToWrite <= totalBytesToWrite)
+ {
+ DPRINT_DBG(VMBUS, "No more space left on outbound ring buffer (needed %u, avail %u)", totalBytesToWrite, byteAvailToWrite);
+
+ SpinlockRelease(OutRingInfo->RingLock);
+
+ DPRINT_EXIT(VMBUS);
+
+ return -1;
+ }
+
+ // Write to the ring buffer
+ nextWriteLocation = GetNextWriteLocation(OutRingInfo);
+
+ for (i=0; i < SgBufferCount; i++)
+ {
+ nextWriteLocation = CopyToRingBuffer(OutRingInfo,
+ nextWriteLocation,
+ SgBuffers[i].Data,
+ SgBuffers[i].Length);
+ }
+
+ // Set previous packet start
+ prevIndices = GetRingBufferIndices(OutRingInfo);
+
+ nextWriteLocation = CopyToRingBuffer(OutRingInfo,
+ nextWriteLocation,
+ &prevIndices,
+ sizeof(UINT64));
+
+ // Make sure we flush all writes before updating the writeIndex
+ MemoryFence();
+
+ // Now, update the write location
+ SetNextWriteLocation(OutRingInfo, nextWriteLocation);
+
+ //DumpRingInfo(OutRingInfo, "AFTER ");
+
+ SpinlockRelease(OutRingInfo->RingLock);
+
+ DPRINT_EXIT(VMBUS);
+
+ return 0;
+}
+
+
+/*++
+
+Name:
+ RingBufferPeek()
+
+Description:
+ Read without advancing the read index
+
+--*/
+int
+RingBufferPeek(
+ RING_BUFFER_INFO* InRingInfo,
+ void* Buffer,
+ UINT32 BufferLen
+ )
+{
+ UINT32 bytesAvailToWrite;
+ UINT32 bytesAvailToRead;
+ UINT32 nextReadLocation=0;
+
+ SpinlockAcquire(InRingInfo->RingLock);
+
+ GetRingBufferAvailBytes(InRingInfo, &bytesAvailToRead, &bytesAvailToWrite);
+
+ // Make sure there is something to read
+ if (bytesAvailToRead < BufferLen )
+ {
+ //DPRINT_DBG(VMBUS, "got callback but not enough to read <avail to read %d read size %d>!!", bytesAvailToRead, BufferLen);
+
+ SpinlockRelease(InRingInfo->RingLock);
+
+ return -1;
+ }
+
+ // Convert to byte offset
+ nextReadLocation = GetNextReadLocation(InRingInfo);
+
+ nextReadLocation = CopyFromRingBuffer(InRingInfo,
+ Buffer,
+ BufferLen,
+ nextReadLocation);
+
+ SpinlockRelease(InRingInfo->RingLock);
+
+ return 0;
+}
+
+
+/*++
+
+Name:
+ RingBufferRead()
+
+Description:
+ Read and advance the read index
+
+--*/
+int
+RingBufferRead(
+ RING_BUFFER_INFO* InRingInfo,
+ PVOID Buffer,
+ UINT32 BufferLen,
+ UINT32 Offset
+ )
+{
+ UINT32 bytesAvailToWrite;
+ UINT32 bytesAvailToRead;
+ UINT32 nextReadLocation=0;
+ UINT64 prevIndices=0;
+
+ ASSERT(BufferLen > 0);
+
+ SpinlockAcquire(InRingInfo->RingLock);
+
+ GetRingBufferAvailBytes(InRingInfo, &bytesAvailToRead, &bytesAvailToWrite);
+
+ DPRINT_DBG(VMBUS, "Reading %u bytes...", BufferLen);
+
+ //DumpRingInfo(InRingInfo, "BEFORE ");
+
+ // Make sure there is something to read
+ if (bytesAvailToRead < BufferLen )
+ {
+ DPRINT_DBG(VMBUS, "got callback but not enough to read <avail to read %d read size %d>!!", bytesAvailToRead, BufferLen);
+
+ SpinlockRelease(InRingInfo->RingLock);
+
+ return -1;
+ }
+
+ nextReadLocation = GetNextReadLocationWithOffset(InRingInfo, Offset);
+
+ nextReadLocation = CopyFromRingBuffer(InRingInfo,
+ Buffer,
+ BufferLen,
+ nextReadLocation);
+
+ nextReadLocation = CopyFromRingBuffer(InRingInfo,
+ &prevIndices,
+ sizeof(UINT64),
+ nextReadLocation);
+
+ // Make sure all reads are done before we update the read index since
+ // the writer may start writing to the read area once the read index is updated
+ MemoryFence();
+
+ // Update the read index
+ SetNextReadLocation(InRingInfo, nextReadLocation);
+
+ //DumpRingInfo(InRingInfo, "AFTER ");
+
+ SpinlockRelease(InRingInfo->RingLock);
+
+ return 0;
+}
+
+
+/*++
+
+Name:
+ CopyToRingBuffer()
+
+Description:
+ Helper routine to copy from source to ring buffer.
+ Assume there is enough room. Handles wrap-around in dest case only!!
+
+--*/
+UINT32
+CopyToRingBuffer(
+ RING_BUFFER_INFO *RingInfo,
+ UINT32 StartWriteOffset,
+ PVOID Src,
+ UINT32 SrcLen)
+{
+ PVOID ringBuffer=GetRingBuffer(RingInfo);
+ UINT32 ringBufferSize=GetRingBufferSize(RingInfo);
+ UINT32 fragLen;
+
+ if (SrcLen > ringBufferSize - StartWriteOffset) // wrap-around detected!
+ {
+ DPRINT_DBG(VMBUS, "wrap-around detected!");
+
+ fragLen = ringBufferSize - StartWriteOffset;
+ memcpy(ringBuffer + StartWriteOffset, Src, fragLen);
+ memcpy(ringBuffer, Src + fragLen, SrcLen - fragLen);
+ }
+ else
+ {
+ memcpy(ringBuffer + StartWriteOffset, Src, SrcLen);
+ }
+
+ StartWriteOffset += SrcLen;
+ StartWriteOffset %= ringBufferSize;
+
+ return StartWriteOffset;
+}
+
+
+/*++
+
+Name:
+ CopyFromRingBuffer()
+
+Description:
+ Helper routine to copy to source from ring buffer.
+ Assume there is enough room. Handles wrap-around in src case only!!
+
+--*/
+UINT32
+CopyFromRingBuffer(
+ RING_BUFFER_INFO *RingInfo,
+ PVOID Dest,
+ UINT32 DestLen,
+ UINT32 StartReadOffset)
+{
+ PVOID ringBuffer=GetRingBuffer(RingInfo);
+ UINT32 ringBufferSize=GetRingBufferSize(RingInfo);
+
+ UINT32 fragLen;
+
+ if (DestLen > ringBufferSize - StartReadOffset) // wrap-around detected at the src
+ {
+ DPRINT_DBG(VMBUS, "src wrap-around detected!");
+
+ fragLen = ringBufferSize - StartReadOffset;
+
+ memcpy(Dest, ringBuffer + StartReadOffset, fragLen);
+ memcpy(Dest + fragLen, ringBuffer, DestLen - fragLen);
+ }
+ else
+ {
+ memcpy(Dest, ringBuffer + StartReadOffset, DestLen);
+ }
+
+ StartReadOffset += DestLen;
+ StartReadOffset %= ringBufferSize;
+
+ return StartReadOffset;
+}
+
+
+// eof