dma.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

         {
            HalpCopyBufferMap(Mdl, RealMapRegisterBase, CurrentVa, Length, FALSE);
      }
   }
   }

   RealMapRegisterBase->Counter = 0;

   return TRUE;
}

/**
 * @name IoMapTransfer
 *
 * Map a DMA for transfer and do the DMA if it's a slave.
 *
 * @param AdapterObject
 *        Adapter object to do the DMA on. Bus-master may pass NULL.
 * @param Mdl
 *        Locked-down user buffer to DMA in to or out of.
 * @param MapRegisterBase
 *        Handle to map registers to use for this dma.
 * @param CurrentVa
 *        Index into Mdl to transfer into/out of.
 * @param Length
 *        Length of transfer. Number of bytes actually transferred on
 *        output.
 * @param WriteToDevice
 *        TRUE if it's an output DMA, FALSE otherwise.
 *
 * @return
 *    A logical address that can be used to program a DMA controller, it's
 *    not meaningful for slave DMA device.
 *
 * @remarks
 *    This function does a copyover to contiguous memory <16MB represented
 *    by the map registers if needed. If the buffer described by MDL can be
 *    used as is no copyover is done.
 *    If it's a slave transfer, this function actually performs it.
 *
 * @implemented
 */

PHYSICAL_ADDRESS STDCALL
IoMapTransfer(
   IN PADAPTER_OBJECT AdapterObject,
   IN PMDL Mdl,
   IN PVOID MapRegisterBase,
   IN PVOID CurrentVa,
   IN OUT PULONG Length,
   IN BOOLEAN WriteToDevice)
{
   PPFN_NUMBER MdlPagesPtr;
   PFN_NUMBER MdlPage1, MdlPage2;
   ULONG ByteOffset;
   ULONG TransferOffset;
   ULONG TransferLength;
   BOOLEAN UseMapRegisters;
   PROS_MAP_REGISTER_ENTRY RealMapRegisterBase;
   PHYSICAL_ADDRESS PhysicalAddress;
   PHYSICAL_ADDRESS HighestAcceptableAddress;
   ULONG Counter;
   DMA_MODE AdapterMode;
   KIRQL OldIrql;
   
   /*
    * Precalculate some values that are used in all cases.
    *
    * ByteOffset is offset inside the page at which the transfer starts.
    * MdlPagesPtr is pointer inside the MDL page chain at the page where the
    *             transfer start.
    * PhysicalAddress is physical address corresponding to the transfer
    *                 start page and offset.
    * TransferLength is the inital length of the transfer, which is reminder
    *                of the first page. The actual value is calculated below.
    *
    * Note that all the variables can change during the processing which
    * takes place below. These are just initial values.
    */

   ByteOffset = BYTE_OFFSET(CurrentVa);

   MdlPagesPtr = MmGetMdlPfnArray(Mdl);
   MdlPagesPtr += ((ULONG_PTR)CurrentVa - (ULONG_PTR)Mdl->StartVa) >> PAGE_SHIFT;

   PhysicalAddress.QuadPart = *MdlPagesPtr << PAGE_SHIFT;
   PhysicalAddress.QuadPart += ByteOffset;

   TransferLength = PAGE_SIZE - ByteOffset;

   /*
    * Special case for bus master adapters with S/G support. We can directly
    * use the buffer specified by the MDL, so not much work has to be done.
    *
    * Just return the passed VA's corresponding physical address and update
    * length to the number of physically contiguous bytes found. Also
    * pages crossing the 4Gb boundary aren't considered physically contiguous.
    */

   if (MapRegisterBase == NULL)
   {
      while (TransferLength < *Length)
      {
         MdlPage1 = *MdlPagesPtr;
         MdlPage2 = *(MdlPagesPtr + 1);
         if (MdlPage1 + 1 != MdlPage2)
            break;
         if ((MdlPage1 ^ MdlPage2) & ~0xFFFFF)
            break;
         TransferLength += PAGE_SIZE;
         MdlPagesPtr++;
      }

      if (TransferLength < *Length)
         *Length = TransferLength;

      return PhysicalAddress;
   }

   /*
    * The code below applies to slave DMA adapters and bus master adapters
    * without hardward S/G support.
    */

   RealMapRegisterBase =
      (PROS_MAP_REGISTER_ENTRY)((ULONG_PTR)MapRegisterBase & ~MAP_BASE_SW_SG);

   /*
    * Try to calculate the size of the transfer. We can only transfer
    * pages that are physically contiguous and that don't cross the 
    * 64Kb boundary (this limitation applies only for ISA controllers).
    */

   while (TransferLength < *Length)
   {
      MdlPage1 = *MdlPagesPtr;
      MdlPage2 = *(MdlPagesPtr + 1);
      if (MdlPage1 + 1 != MdlPage2)
         break;
      if (!HalpEisaDma && ((MdlPage1 ^ MdlPage2) & ~0xF))
         break;
      TransferLength += PAGE_SIZE;
      MdlPagesPtr++;
   }

   if (TransferLength > *Length)
      TransferLength = *Length;

   /*
    * If we're about to simulate software S/G and not all the pages are
    * physically contiguous then we must use the map registers to store
    * the data and allow the whole transfer to proceed at once.
    */

   if ((ULONG_PTR)MapRegisterBase & MAP_BASE_SW_SG &&
       TransferLength < *Length)
   {
      UseMapRegisters = TRUE;
      PhysicalAddress = RealMapRegisterBase->PhysicalAddress;
      PhysicalAddress.QuadPart += ByteOffset;
      TransferLength = *Length;
      RealMapRegisterBase->Counter = ~0;
      Counter = 0;
   }
   else
   {
      /*
       * This is ordinary DMA transfer, so just update the progress
       * counters. These are used by IoFlushAdapterBuffers to track
       * the transfer progress.
       */

      UseMapRegisters = FALSE;
      Counter = RealMapRegisterBase->Counter;
      RealMapRegisterBase->Counter += BYTES_TO_PAGES(ByteOffset + TransferLength);

      /*
       * Check if the buffer doesn't exceed the highest physical address
       * limit of the device. In that case we must use the map registers to
       * store the data.
       */

      HighestAcceptableAddress = HalpGetAdapterMaximumPhysicalAddress(AdapterObject);
      if (PhysicalAddress.QuadPart + TransferLength >
          HighestAcceptableAddress.QuadPart)
      {
         UseMapRegisters = TRUE;
         PhysicalAddress = RealMapRegisterBase[Counter].PhysicalAddress;
         PhysicalAddress.QuadPart += ByteOffset;
         if ((ULONG_PTR)MapRegisterBase & MAP_BASE_SW_SG)
         {
            RealMapRegisterBase->Counter = ~0;
            Counter = 0;
         }
      }
   }

   /*
    * If we decided to use the map registers (see above) and we're about
    * to transfer data to the device then copy the buffers into the map
    * register memory.
    */

   if (UseMapRegisters && WriteToDevice)
   {
      HalpCopyBufferMap(Mdl, RealMapRegisterBase + Counter,
                        CurrentVa, TransferLength, WriteToDevice);
   }

   /*
    * Return the length of transfer that actually takes place.
    */

   *Length = TransferLength;

   /*
    * If we're doing slave (system) DMA then program the (E)ISA controller
    * to actually start the transfer.
    */

   if (AdapterObject != NULL && !AdapterObject->MasterDevice)
   {
      AdapterMode = AdapterObject->AdapterMode;
      
      if (WriteToDevice)
      {
         AdapterMode.TransferType = WRITE_TRANSFER;
      }
      else
      {
         AdapterMode.TransferType = READ_TRANSFER;
         if (AdapterObject->IgnoreCount)
         {
            RtlZeroMemory((PUCHAR)RealMapRegisterBase[Counter].VirtualAddress +
                          ByteOffset, TransferLength);
         }
      }

      TransferOffset = PhysicalAddress.LowPart & 0xFFFF;
      if (AdapterObject->Width16Bits)
      {
         TransferLength >>= 1;
         TransferOffset >>= 1;
      }

      OldIrql = KfAcquireSpinLock(&AdapterObject->MasterAdapter->SpinLock);

      if (AdapterObject->AdapterNumber == 1)
      {
         PDMA1_CONTROL DmaControl1 = AdapterObject->AdapterBaseVa;

         /* Reset Register */
         WRITE_PORT_UCHAR(&DmaControl1->ClearBytePointer, 0);
         /* Set the Mode */
         WRITE_PORT_UCHAR(&DmaControl1->Mode, AdapterMode.Byte);
         /* Set the Offset Register */
         WRITE_PORT_UCHAR(&DmaControl1->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseAddress,
                          (UCHAR)(TransferOffset));
         WRITE_PORT_UCHAR(&DmaControl1->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseAddress,
                          (UCHAR)(TransferOffset >> 8));
         /* Set the Page Register */
         WRITE_PORT_UCHAR(AdapterObject->PagePort +
                          FIELD_OFFSET(EISA_CONTROL, DmaController1Pages),
                          (UCHAR)(PhysicalAddress.LowPart >> 16));
         if (HalpEisaDma)
         {
            WRITE_PORT_UCHAR(AdapterObject->PagePort +
                             FIELD_OFFSET(EISA_CONTROL, DmaController2Pages),
                             0);
         }
         /* Set the Length */
         WRITE_PORT_UCHAR(&DmaControl1->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseCount,
                          (UCHAR)(TransferLength - 1));
         WRITE_PORT_UCHAR(&DmaControl1->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseCount,
                          (UCHAR)((TransferLength - 1) >> 8));
         /* Unmask the Channel */
         WRITE_PORT_UCHAR(&DmaControl1->SingleMask,
                          AdapterObject->ChannelNumber | DMA_CLEARMASK);
      }
      else
      {
         PDMA2_CONTROL DmaControl2 = AdapterObject->AdapterBaseVa;

         /* Reset Register */
         WRITE_PORT_UCHAR(&DmaControl2->ClearBytePointer, 0);
         /* Set the Mode */
         WRITE_PORT_UCHAR(&DmaControl2->Mode, AdapterMode.Byte);
         /* Set the Offset Register */
         WRITE_PORT_UCHAR(&DmaControl2->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseAddress,
                          (UCHAR)(TransferOffset));
         WRITE_PORT_UCHAR(&DmaControl2->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseAddress,
                          (UCHAR)(TransferOffset >> 8));
         /* Set the Page Register */
         WRITE_PORT_UCHAR(AdapterObject->PagePort +
                          FIELD_OFFSET(EISA_CONTROL, DmaController1Pages),
                          (UCHAR)(PhysicalAddress.u.LowPart >> 16));
         if (HalpEisaDma)
         {
            WRITE_PORT_UCHAR(AdapterObject->PagePort +
                             FIELD_OFFSET(EISA_CONTROL, DmaController2Pages),
                             0);
         }
         /* Set the Length */
         WRITE_PORT_UCHAR(&DmaControl2->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseCount,
                          (UCHAR)(TransferLength - 1));
         WRITE_PORT_UCHAR(&DmaControl2->DmaAddressCount[AdapterObject->ChannelNumber].DmaBaseCount,
                          (UCHAR)((TransferLength - 1) >> 8));
         /* Unmask the Channel */
         WRITE_PORT_UCHAR(&DmaControl2->SingleMask,
                          AdapterObject->ChannelNumber | DMA_CLEARMASK);
      }

      KfReleaseSpinLock(&AdapterObject->MasterAdapter->SpinLock, OldIrql);
   }

   /*
    * Return physical address of the buffer with data that is used for the
    * transfer. It can either point inside the Mdl that was passed by the
    * caller or into the map registers if the Mdl buffer can't be used
    * directly.
    */

   return PhysicalAddress;
}

/**
 * @name HalFlushCommonBuffer
 *
 * @implemented
 */
BOOLEAN
NTAPI
HalFlushCommonBuffer(IN PADAPTER_OBJECT AdapterObject,
                     IN ULONG Length,
                     IN PHYSICAL_ADDRESS LogicalAddress,
                     IN PVOID VirtualAddress)
{
    /* Function always returns true */
    return TRUE;
}

/*
 * @implemented
 */
PVOID
NTAPI
HalAllocateCrashDumpRegisters(IN PADAPTER_OBJECT AdapterObject,
                              IN OUT PULONG NumberOfMapRegisters)
{
    PADAPTER_OBJECT MasterAdapter = AdapterObject->MasterAdapter;
    ULONG MapRegisterNumber;

    /* Check if it needs map registers */
    if (AdapterObject->NeedsMapRegisters)
    {
        /* Check if we have enough */
        if (*NumberOfMapRegisters > AdapterObject->MapRegistersPerChannel)
        {
            /* We don't, fail */
            AdapterObject->NumberOfMapRegisters = 0;
            return NULL;
        }

        /* Try to find free map registers */
        MapRegisterNumber = -1;
        MapRegisterNumber = RtlFindClearBitsAndSet(MasterAdapter->MapRegisters,
                                                   *NumberOfMapRegisters,
                                                   0);

        /* Check if nothing was found */
        if (MapRegisterNumber == -1)
        {
            /* No free registers found, so use the base registers */
            RtlSetBits(MasterAdapter->MapRegisters,
                       0,
                       *NumberOfMapRegisters);
            MapRegisterNumber = 0;
        }

        /* Calculate the new base */
        AdapterObject->MapRegisterBase =
            (PROS_MAP_REGISTER_ENTRY)(MasterAdapter->MapRegisterBase +
                                      MapRegisterNumber);

        /* Check if scatter gather isn't supported */
        if (!AdapterObject->ScatterGather)
        {
            /* Set the flag */
            AdapterObject->MapRegisterBase =
                (PROS_MAP_REGISTER_ENTRY)
                ((ULONG_PTR)AdapterObject->MapRegisterBase | MAP_BASE_SW_SG);
        }
    }
    else
    {
        AdapterObject->MapRegisterBase = NULL;
        AdapterObject->NumberOfMapRegisters = 0;
    }

    /* Return the base */
    return AdapterObject->MapRegisterBase;
}

/* EOF */