xbuf_descriptor.h

linux嵌入式系统的dma方式的实现代码

*
* DestinationAddress contains the destination address field for the buffer
* descriptor.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetDestAddress(InstancePtr, Destination) \
    (*((Xuint32 *)InstancePtr + XBD_DESTINATION_OFFSET) = (Xuint32)Destination)

/*****************************************************************************/
/**
*
* This function gets the length of the data transfer if the buffer descriptor
* has been processed by the DMA channel hardware.  If the buffer descriptor
* has not been processed, the return value will be zero indicating that no data
* has been transferred yet.  This function uses both the length and requested
* length fields of the buffer descriptor to determine the number of bytes
* transferred by the DMA operation. The length field of the buffer descriptor
* contains the number of bytes remaining from the requested length.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* The number of bytes which have been transferred by a DMA operation on the
* buffer descriptor.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_GetLength(InstancePtr)                           \
    (Xuint32)(*((Xuint32 *)InstancePtr + XBD_RQSTED_LENGTH_OFFSET) -    \
              *((Xuint32 *)InstancePtr + XBD_LENGTH_OFFSET))

/*****************************************************************************/
/**
*
* This function sets the length and the requested length fields of the buffer
* descriptor.  The length field indicates the number of bytes to transfer for
* the DMA operation and the requested length is written with the same value.
* The requested length is not modified by the DMA hardware while the length
* field is modified by the hardware to indicate the number of bytes remaining
* in the transfer after the transfer is complete.  The requested length allows
* the software to calculate the actual number of bytes transferred for the DMA
* operation.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @param
*
* Length contains the length to put in the length and requested length fields
* of the buffer descriptor.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetLength(InstancePtr, Length)                       \
{                                                                           \
    (*((Xuint32 *)InstancePtr + XBD_LENGTH_OFFSET) = (Xuint32)(Length));    \
    (*((Xuint32 *)InstancePtr + XBD_RQSTED_LENGTH_OFFSET) = (Xuint32)(Length));\
}

/*****************************************************************************/
/**
*
* This function gets the status field of a buffer descriptor component. The
* status field is written to the buffer descriptor by the DMA channel hardware
* after processing of a buffer descriptor is complete.  The status field
* indicates the status of the DMA operation.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* The status field contents of the buffer descriptor. One or more of the
* following values may be contained the field. Each of the values are
* unique bit masks.
*                               <br><br>
* - XDC_DMASR_BUSY_MASK         The DMA channel is busy
*                               <br><br>
* - XDC_DMASR_BUS_ERROR_MASK    A bus error occurred
*                               <br><br>
* - XDC_DMASR_BUS_TIMEOUT_MASK  A bus timeout occurred
*                               <br><br>
* - XDC_DMASR_LAST_BD_MASK      The last buffer descriptor of a packet
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_GetStatus(InstancePtr)    \
    (Xuint32)(*((Xuint32 *)InstancePtr + XBD_STATUS_OFFSET))

/*****************************************************************************/
/**
*
* This function sets the status field of a buffer descriptor component.  The
* status field is written to the buffer descriptor by the DMA channel hardware
* after processing of a buffer descriptor is complete.  This function would
* typically be used during debugging of buffer descriptor processing.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @param
*
* Status contains the status field for the buffer descriptor.
* The status register contents of the DMA channel. One or more of the
* following values may be contained the register. Each of the values are
* unique bit masks.
* - XDC_DMASR_BUSY_MASK         The DMA channel is busy
* - XDC_DMASR_BUS_ERROR_MASK    A bus error occurred
* - XDC_DMASR_BUS_TIMEOUT_MASK  A bus timeout occurred
* - XDC_DMASR_LAST_BD_MASK      The last buffer descriptor of a packet
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetStatus(InstancePtr, Status)    \
    (*((Xuint32 *)InstancePtr + XBD_STATUS_OFFSET) = (Xuint32)Status)

/*****************************************************************************/
/**
*
* This function determines if this buffer descriptor is marked as being the
* last in the status field.  A packet may be broken up across multiple
* buffer descriptors such that the last buffer descriptor is the end of the
* packet.  The DMA channel hardware copies the status register contents to
* the buffer descriptor of the DMA channel after processing of the buffer
* descriptor is complete.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* XTRUE if the buffer descriptor is marked as last in the status field,
* otherwise, XFALSE.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_IsLastStatus(InstancePtr) \
    (Xboolean)((*((Xuint32 *)InstancePtr + XBD_STATUS_OFFSET) & \
               XDC_STATUS_LAST_BD_MASK) == XDC_STATUS_LAST_BD_MASK)

/*****************************************************************************/
/**
*
* This function gets the device status field of the buffer descriptor.  The
* device status is device specific such that the definition of the contents
* of this field are not defined in this function. The device is defined as the
* device which is using the DMA channel, such as an ethernet controller.  The
* DMA channel hardware copies the contents of the device status register into
* the buffer descriptor when processing of the buffer descriptor is complete.
* This value is typically used by the device driver for the device to determine
* the status of the DMA operation with respect to the device.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* The device status field of the buffer descriptor.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_GetDeviceStatus(InstancePtr) \
    ((Xuint32)(*((Xuint32 *)InstancePtr + XBD_DEVICE_STATUS_OFFSET)))

/*****************************************************************************/
/**
*
* This function sets the device status field of the buffer descriptor.  The
* device status is device specific such that the definition of the contents
* of this field are not defined in this function. The device is defined as the
* device which is using the DMA channel, such as an ethernet controller.  This
* function is typically only used for debugging/testing.
*
* The DMA channel hardware copies the contents of the device status register
* into the buffer descriptor when processing of the buffer descriptor is
* complete.  This value is typically used by the device driver for the device
* to determine the status of the DMA operation with respect to the device.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @param
*
* Status contains the device status field for the buffer descriptor.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetDeviceStatus(InstancePtr, Status) \
{                                                                   \
    Xuint32 Register;                                               \
    Register = (*((Xuint32 *)InstancePtr + XBD_DEVICE_STATUS_OFFSET));     \
    Register &= XDC_DMASR_RX_CS_RAW_MASK;                         \
    (*((Xuint32 *)InstancePtr + XBD_DEVICE_STATUS_OFFSET)) =               \
              Register | ((Xuint32) (Status));               \
}

/*****************************************************************************/
/**
*
* This function gets the next pointer field of the buffer descriptor.  This
* field is used to link the buffer descriptors together such that multiple DMA
* operations can be automated for scatter gather.  It also allows a single
* packet to be broken across multiple buffer descriptors.  The DMA channel
* hardware traverses the list of buffer descriptors using the next pointer
* of each buffer descriptor.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* The next pointer field of the buffer descriptor.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_GetNextPtr(InstancePtr) \
    (XBufDescriptor *)(*((Xuint32 *)InstancePtr + XBD_NEXT_PTR_OFFSET))

/*****************************************************************************/
/**
*
* This function sets the next pointer field of the buffer descriptor.  This
* field is used to link the buffer descriptors together such that many DMA
* operations can be automated for scatter gather.  It also allows a single
* packet to be broken across multiple buffer descriptors.  The DMA channel
* hardware traverses the list of buffer descriptors using the next pointer
* of each buffer descriptor.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @param
*
* NextPtr contains the next pointer field for the buffer descriptor.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetNextPtr(InstancePtr, NextPtr) \
    (*((Xuint32 *)InstancePtr + XBD_NEXT_PTR_OFFSET) = (Xuint32)NextPtr)

/*****************************************************************************/
/**
*
* This function gets the ID field of the buffer descriptor.  The ID field is
* provided to allow a device driver to correlate the buffer descriptor to other
* data structures which may be operating system specific, such as a pointer to
* a higher level memory block. The ID field is not used by the DMA channel
* hardware and is application specific.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @return
*
* The ID field of the buffer descriptor.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_GetId(InstancePtr) \
    (Xuint32)(*((Xuint32 *)InstancePtr + XBD_ID_OFFSET))

/*****************************************************************************/
/**
*
* This function sets the ID field of the buffer descriptor.  The ID field is
* provided to allow a device driver to correlate the buffer descriptor to other
* data structures which may be operating system specific, such as a pointer to
* a higher level memory block. The ID field is not used by the DMA channel
* hardware and is application specific.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.
*
* @param
*
* Id contains the ID field for the buffer descriptor.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
#define XBufDescriptor_SetId(InstancePtr, Id) \
    (*((Xuint32 *)InstancePtr + XBD_ID_OFFSET) = (Xuint32)Id)

/*****************************************************************************/
/**
*
* This function gets the flags field of the buffer descriptor.  The flags
* field is not used by the DMA channel hardware and is used for software
* processing of buffer descriptors.
*
* @param
*
* InstancePtr points to the buffer descriptor to operate on.