/**
*
* This function receives a byte from PS/2. It operates in the polling mode
* and blocks until a byte of data is received.
*
* @param BaseAddress contains the base address of the PS/2 port.
*
* @return The data byte received by PS/2.
*
* @note None.
*
*****************************************************************************/
u8
XPs2_RecvByte(u32 BaseAddress)
{
while (XPs2_mIsReceiveEmpty(BaseAddress)) {
}
return (u8) XIo_In8(BaseAddress + XPS2_RX_REG_OFFSET);
}
/**
*
* This function receives a buffer that has been previously specified by setting
* up the instance variables of the instance. This function is designed to be
* an internal function for the XPs2 component such that it may be called
* from a shell function that sets up the buffer or from an interrupt handler.
*
* This function will attempt to receive a specified number of bytes of data
* from PS/2 and store it into the specified buffer. This function is
* designed for either polled or interrupt driven modes. It is non-blocking
* such that it will return if there is no data has already received.
*
* In a polled mode, this function will only receive 1 byte which is as much
* data as the receiver can buffer. The application may need to call it
* repeatedly to receive a buffer. Polled mode is the default mode of operation
* for the driver.
*
* In interrupt mode, this function will start receiving and then the interrupt
* handler of the driver will continue until the buffer has been received. A
* callback function, as specified by the application, will be called to indicate
* the completion of receiving the buffer or when any receive errors or timeouts
* occur. Interrupt mode must be enabled using the SetOptions function.
*
* @param InstancePtr is a pointer to the XPs2 instance to be worked on.
*
* @return
*
* The number of bytes received.
*
* @note
*
* None.
*
*****************************************************************************/
unsigned int XPs2_ReceiveBuffer(XPs2 *InstancePtr)
{
unsigned int ReceivedCount = 0;
/*
* Loop until there is no more date buffered by the PS/2 receiver or the
* specified number of bytes has been received
*/
while (ReceivedCount < InstancePtr->ReceiveBuffer.RemainingBytes)
{
/*
* If there is data ready to be read , then put the next byte
* read into the specified buffer
*/
if (!XPs2_mIsReceiveEmpty(InstancePtr->BaseAddress))
{
InstancePtr->ReceiveBuffer.NextBytePtr[ReceivedCount++] =
XPs2_RecvByte(InstancePtr->BaseAddress);
}
/*
* There is no more data buffered, so exit such that this function does
* not block waiting for data
*/
else
{
break;
}
}
/*
* Update the receive buffer to reflect the number of bytes that was
* received
*/
InstancePtr->ReceiveBuffer.NextBytePtr += ReceivedCount;
InstancePtr->ReceiveBuffer.RemainingBytes -= ReceivedCount;
return ReceivedCount;
}