/*++
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;
}
/* Allocate Physical Page below 1 mb */
PhysAddr_t MmPhysicalAllocateBlockDma(void)
{
/* Get free bit */
int bit;
/* Get Spinlock */
SpinlockAcquire(&MemoryLock);
/* Get bit */
bit = MmGetFreeMapBitLow();
/* Release Spinlock */
SpinlockRelease(&MemoryLock);
/* Sanity */
assert(bit != -1);
/* Set it */
MmMemoryMapSetBit(bit);
/* Statistics */
MemoryBlocksUsed++;
return (PhysAddr_t)(bit * PAGE_SIZE);
}
/* Free Physical Page */
void MmPhysicalFreeBlock(PhysAddr_t Addr)
{
/* Calculate Bit */
int bit = (int32_t)(Addr / PAGE_SIZE);
/* Sanity */
if (Addr > MemorySize
|| Addr < 0x200000)
return;
/* Get Spinlock */
SpinlockAcquire(&MemoryLock);
/* Sanity */
assert(MmMemoryMapTestBit(bit) != 0);
/* Free it */
MmMemoryMapUnsetBit(bit);
/* Release Spinlock */
SpinlockRelease(&MemoryLock);
/* Statistics */
if (MemoryBlocksUsed != 0)
MemoryBlocksUsed--;
}
DevId_t DmCreateDevice(char *Name, MCoreDevice_t *Device)
{
/* Grap lock */
SpinlockAcquire(&GlbDmLock);
/* Set name and data */
Device->Name = strdup(Name);
Device->Id = GlbDmIdentfier;
/* Increase */
GlbDmIdentfier++;
/* Release */
SpinlockRelease(&GlbDmLock);
/* Add to list */
list_append(GlbDmDeviceList, list_create_node(Device->Id, (void*)Device));
/* Call some broadcast function so systems know a new device is avaiable
* depending on the device type */
switch (Device->Type)
{
/* Give access to timer */
case DeviceTimer:
{
/* Cast */
MCoreTimerDevice_t *Timer = (MCoreTimerDevice_t*)Device->Data;
Timer->ReportMs = TimersApplyMs;
} break;
/* Give access to input */
case DeviceInput:
{
/* Cast */
MCoreInputDevice_t *Input = (MCoreInputDevice_t*)Device->Data;
Input->ReportEvent = EmCreateEvent;
} break;
/* Register with Vfs */
case DeviceStorage:
{
/* Call */
VfsRegisterDisk(Device->Id);
} break;
/* No special actions */
default:
break;
}
/* Info Log */
LogInformation("DRVM", "New Device: %s", Name);
/* Done */
return Device->Id;
}
/*++
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:
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;
}