text: /******************************************************************************
  *
  * Copyright (C) 2002 - 2014 Xilinx, Inc.  All rights reserved.
  *
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  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * Use of the Software is limited solely to applications:
  * (a) running on a Xilinx device, or
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  ******************************************************************************/
  /****************************************************************************/
  /**
  *
  * @file xuartlite_intr.c
  *
  * This file contains interrupt-related functions for the UART Lite component
  * (XUartLite).
  *
  * <pre>
  * MODIFICATION HISTORY:
  *
  * Ver   Who  Date     Changes
  * ----- ---- -------- -----------------------------------------------
  * 1.00a ecm  08/31/01 First release
  * 1.00b jhl  02/21/02 Repartitioned the driver for smaller files
  * 1.02a rpm  02/14/07 Added check for outstanding transmission before
  *			calling the send callback (avoids extraneous
  *			callback invocations)
  * 2.00a ktn  10/20/09 Updated to use HAL Processor APIs. The macros have been
  *		      renamed to remove _m from the name.
  * </pre>
  *
  *****************************************************************************/
  
  /***************************** Include Files ********************************/
  
  #include "xuartlite.h"
  #include "xuartlite_i.h"
  #include "xil_io.h"
  
  /************************** Constant Definitions ****************************/
  
  /**************************** Type Definitions ******************************/
  
  /***************** Macros (Inline Functions) Definitions ********************/
  
  /************************** Function Prototypes *****************************/
  
  static void ReceiveDataHandler(XUartLite *InstancePtr);
  static void SendDataHandler(XUartLite *InstancePtr);
  
  /************************** Variable Definitions ****************************/
  
  typedef void (*Handler)(XUartLite *InstancePtr);
  
  /****************************************************************************/
  /**
  *
  * This function sets the handler that will be called when an event (interrupt)
  * occurs in the driver. The purpose of the handler is to allow application
  * specific processing to be performed.
  *
  * @param	InstancePtr is a pointer to the XUartLite instance.
  * @param	FuncPtr is the pointer to the callback function.
  * @param	CallBackRef is the upper layer callback reference passed back
  *		when the callback function is invoked.
  *
  * @return	None.
  *
  * @note		There is no assert on the CallBackRef since the driver doesn't
  *		know what it is (nor should it)
  *
  *****************************************************************************/
  void XUartLite_SetRecvHandler(XUartLite *InstancePtr,
  				XUartLite_Handler FuncPtr, void *CallBackRef)
  {
  	/*
  	 * Assert validates the input arguments
  	 * CallBackRef not checked, no way to know what is valid
  	 */
  	Xil_AssertVoid(InstancePtr != NULL);
  	Xil_AssertVoid(FuncPtr != NULL);
  	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
  
  	InstancePtr->RecvHandler = FuncPtr;
  	InstancePtr->RecvCallBackRef = CallBackRef;
  }
  
  /****************************************************************************/
  /**
  *
  * This function sets the handler that will be called when an event (interrupt)
  * occurs in the driver. The purpose of the handler is to allow application
  * specific processing to be performed.
  *
  * @param	InstancePtr is a pointer to the XUartLite instance .
  * @param	FuncPtr is the pointer to the callback function.
  * @param	CallBackRef is the upper layer callback reference passed back
  *		when the callback function is invoked.
  *
  * @return 	None.
  *
  * @note		There is no assert on the CallBackRef since the driver doesn't
  *		know what it is (nor should it)
  *
  *****************************************************************************/
  void XUartLite_SetSendHandler(XUartLite *InstancePtr,
  				XUartLite_Handler FuncPtr, void *CallBackRef)
  {
  	/*
  	 * Assert validates the input arguments
  	 * CallBackRef not checked, no way to know what is valid
  	 */
  	Xil_AssertVoid(InstancePtr != NULL);
  	Xil_AssertVoid(FuncPtr != NULL);
  	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
  
  	InstancePtr->SendHandler = FuncPtr;
  	InstancePtr->SendCallBackRef = CallBackRef;
  }
  
  /****************************************************************************/
  /**
  *
  * This function is the interrupt handler for the UART lite driver.
  * It must be connected to an interrupt system by the user such that it is
  * called when an interrupt for any UART lite occurs. This function
  * does not save or restore the processor context such that the user must
  * ensure this occurs.
  *
  * @param	InstancePtr contains a pointer to the instance of the UART that
  *		the interrupt is for.
  *
  * @return	None.
  *
  * @note		None.
  *
  ******************************************************************************/
  void XUartLite_InterruptHandler(XUartLite *InstancePtr)
  {
  	u32 IsrStatus;
  
  	Xil_AssertVoid(InstancePtr != NULL);
  
  	/*
  	 * Read the status register to determine which, coulb be both
  	 * interrupt is active
  	 */
  	IsrStatus = XUartLite_ReadReg(InstancePtr->RegBaseAddress,
  					XUL_STATUS_REG_OFFSET);
  
  	if ((IsrStatus & (XUL_SR_RX_FIFO_FULL |
  		XUL_SR_RX_FIFO_VALID_DATA)) != 0) {
  		ReceiveDataHandler(InstancePtr);
  	}
  
  	if (((IsrStatus & XUL_SR_TX_FIFO_EMPTY) != 0) &&
  		(InstancePtr->SendBuffer.RequestedBytes > 0)) {
  		SendDataHandler(InstancePtr);
  	}
  }
  
  /****************************************************************************/
  /**
  *
  * This function handles the interrupt when data is received, either a single
  * byte when FIFOs are not enabled, or multiple bytes with the FIFO.
  *
  * @param	InstancePtr is a pointer to the XUartLite instance.
  *
  * @return	None.
  *
  * @note		None.
  *
  *****************************************************************************/
  static void ReceiveDataHandler(XUartLite *InstancePtr)
  {
  	/*
  	 * If there are bytes still to be received in the specified buffer
  	 * go ahead and receive them
  	 */
  	if (InstancePtr->ReceiveBuffer.RemainingBytes != 0) {
  		XUartLite_ReceiveBuffer(InstancePtr);
  	}
  
  	/*
  	 * If the last byte of a message was received then call the application
  	 * handler, this code should not use an else from the previous check of
  	 * the number of bytes to receive because the call to receive the buffer
  	 * updates the bytes to receive
  	 */
  	if (InstancePtr->ReceiveBuffer.RemainingBytes == 0) {
  		InstancePtr->RecvHandler(InstancePtr->RecvCallBackRef,
  		InstancePtr->ReceiveBuffer.RequestedBytes -
  		InstancePtr->ReceiveBuffer.RemainingBytes);
  	}
  
  	/*
  	 * Update the receive stats to reflect the receive interrupt
  	 */
  	InstancePtr->Stats.ReceiveInterrupts++;
  }
  
  /****************************************************************************/
  /**
  *
  * This function handles the interrupt when data has been sent, the transmit
  * FIFO is empty (transmitter holding register).
  *
  * @param	InstancePtr is a pointer to the XUartLite instance .
  *
  * @return	None.
  *
  * @note		None.
  *
  *****************************************************************************/
  static void SendDataHandler(XUartLite *InstancePtr)
  {
  	/*
  	 * If there are not bytes to be sent from the specified buffer,
  	 * call the callback function
  	 */
  	if (InstancePtr->SendBuffer.RemainingBytes == 0) {
  		int SaveReq;
  
  		/*
  		 * Save and zero the requested bytes since transmission
  		 * is complete
  		 */
  		SaveReq = InstancePtr->SendBuffer.RequestedBytes;
  		InstancePtr->SendBuffer.RequestedBytes = 0;
  
  		/*
  		 * Call the application handler to indicate
  		 * the data has been sent
  		 */
  		InstancePtr->SendHandler(InstancePtr->SendCallBackRef, SaveReq);
  	}
  	/*
  	 * Otherwise there is still more data to send in the specified buffer
  	 * so go ahead and send it
  	 */
  	else {
  		XUartLite_SendBuffer(InstancePtr);
  	}
  
  	/*
  	 * Update the transmit stats to reflect the transmit interrupt
  	 */
  	InstancePtr->Stats.TransmitInterrupts++;
  }
  
  
  /*****************************************************************************/
  /**
  *
  * This function disables the UART interrupt. After calling this function,
  * data may still be received by the UART but no interrupt will be generated
  * since the hardware device has no way to disable the receiver.
  *
  * @param	InstancePtr is a pointer to the XUartLite instance.
  *
  * @return	None.
  *
  * @note		None.
  *
  *****************************************************************************/
  void XUartLite_DisableInterrupt(XUartLite *InstancePtr)
  {
  	Xil_AssertVoid(InstancePtr != NULL);
  	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
  
  	/*
  	 * Write to the control register to disable the interrupts, the only
  	 * other bits in this register are the FIFO reset bits such that
  	 * writing them to zero will not affect them.
  	 */
  	XUartLite_WriteReg(InstancePtr->RegBaseAddress,
  				XUL_CONTROL_REG_OFFSET, 0);
  }
  
  /*****************************************************************************/
  /**
  *
  * This function enables the UART interrupt such that an interrupt will occur
  * when data is received or data has been transmitted. The device contains
  * 16 byte receive and transmit FIFOs such that an interrupt is generated
  * anytime there is data in the receive FIFO and when the transmit FIFO
  * transitions from not empty to empty.
  *
  * @param	InstancePtr is a pointer to the XUartLite instance.
  *
  * @return	None.
  *
  * @note		None.
  *
  *****************************************************************************/
  void XUartLite_EnableInterrupt(XUartLite *InstancePtr)
  {
  	Xil_AssertVoid(InstancePtr != NULL);
  	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
  
  	/*
  	 * Write to the control register to enable the interrupts, the only
  	 * other bits in this register are the FIFO reset bits such that
  	 * writing them to zero will not affect them.
  	 */
  	XUartLite_WriteReg(InstancePtr->RegBaseAddress,
  				XUL_CONTROL_REG_OFFSET, XUL_CR_ENABLE_INTR);
  }
  
  