xuartps.c

自学ZedBoard：使用IP通过ARM PS访问FPGA（源代码）

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/****************************************************************************/
/**
*
* @file xuartps.c
*
* This file contains the implementation of the interface functions for XUartPs
* driver. Refer to the header file xuartps.h for more detailed information.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who    Date	 Changes
* ----- ------ -------- ----------------------------------------------
* 1.00	drg/jz 01/13/10 First Release
* </pre>
*
*****************************************************************************/

/***************************** Include Files ********************************/

#include "xstatus.h"
#include "xuartps.h"
#include "xil_io.h"

/************************** Constant Definitions ****************************/

/* The following constant defines the amount of error that is allowed for
 * a specified baud rate. This error is the difference between the actual
 * baud rate that will be generated using the specified clock and the
 * desired baud rate.
 */
#define XUARTPS_MAX_BAUD_ERROR_RATE		 3	/* max % error allowed */

/**************************** Type Definitions ******************************/


/***************** Macros (Inline Functions) Definitions ********************/


/************************** Function Prototypes *****************************/

static void XUartPs_StubHandler(void *CallBackRef, u32 Event,
				 unsigned int ByteCount);

unsigned int XUartPs_SendBuffer(XUartPs *InstancePtr);

unsigned int XUartPs_ReceiveBuffer(XUartPs *InstancePtr);

/************************** Variable Definitions ****************************/

/****************************************************************************/
/**
*
* Initializes a specific XUartPs instance such that it is ready to be used.
* The data format of the device is setup for 8 data bits, 1 stop bit, and no
* parity by default. The baud rate is set to a default value specified by
* Config->DefaultBaudRate if set, otherwise it is set to 19.2K baud. The
* receive FIFO threshold is set for 8 bytes. The default operating mode of the
* driver is polled mode.
*
* @param	InstancePtr is a pointer to the XUartPs instance.
* @param	Config is a reference to a structure containing information
*		about a specific XUartPs driver.
* @param	EffectiveAddr is the device base address in the virtual memory
*		address space. The caller is responsible for keeping the address
*		mapping from EffectiveAddr to the device physical base address
*		unchanged once this function is invoked. Unexpected errors may
*		occur if the address mapping changes after this function is
*		called. If address translation is not used, pass in the physical
*		address instead.
*
* @return
*
*		- XST_SUCCESS if initialization was successful
*		- XST_UART_BAUD_ERROR if the baud rate is not possible because
*		  the inputclock frequency is not divisible with an acceptable
*		  amount of error
*
* @note
*
* The default configuration for the UART after initialization is:
*
* - 19,200 bps or XPAR_DFT_BAUDRATE if defined
* - 8 data bits
* - 1 stop bit
* - no parity
* - FIFO's are enabled with a receive threshold of 8 bytes
* - The RX timeout is enabled with a timeout of 1 (4 char times)
*
*   All interrupts are disabled.
*
*****************************************************************************/
int XUartPs_CfgInitialize(XUartPs *InstancePtr,
				   XUartPs_Config * Config, u32 EffectiveAddr)
{
	int Status;
	u32 ModeRegister;
	u32 BaudRate;

	/*
	 * Assert validates the input arguments
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(Config != NULL);

	/*
	 * Setup the driver instance using passed in parameters
	 */
	InstancePtr->Config.BaseAddress = EffectiveAddr;
	InstancePtr->Config.InputClockHz = Config->InputClockHz;
	InstancePtr->Config.ModemPinsConnected = Config->ModemPinsConnected;

	/*
	 * Initialize other instance data to default values
	 */
	InstancePtr->Handler = XUartPs_StubHandler;

	InstancePtr->SendBuffer.NextBytePtr = NULL;
	InstancePtr->SendBuffer.RemainingBytes = 0;
	InstancePtr->SendBuffer.RequestedBytes = 0;

	InstancePtr->ReceiveBuffer.NextBytePtr = NULL;
	InstancePtr->ReceiveBuffer.RemainingBytes = 0;
	InstancePtr->ReceiveBuffer.RequestedBytes = 0;

	/*
	 * Flag that the driver instance is ready to use
	 */
	InstancePtr->IsReady = XIL_COMPONENT_IS_READY;

	/*
	 * Set the default baud rate here, can be changed prior to
	 * starting the device
	 */
	BaudRate = XUARTPS_DFT_BAUDRATE;
	Status = XUartPs_SetBaudRate(InstancePtr, BaudRate);
	if (Status != XST_SUCCESS) {
		InstancePtr->IsReady = 0;
		return Status;
	}

	/*
	 * Set up the default data format: 8 bit data, 1 stop bit, no
	 * parity
	 */
	ModeRegister = XUartPs_ReadReg(InstancePtr->Config.BaseAddress,
				  XUARTPS_MR_OFFSET);

	/*
	 * Mask off what's already there
	 */
	ModeRegister &= ~(XUARTPS_MR_CHARLEN_MASK |
					 XUARTPS_MR_STOPMODE_MASK |
					 XUARTPS_MR_PARITY_MASK);

	/*
	 * Set the register value to the desired data format
	 */
	ModeRegister |=	(XUARTPS_MR_CHARLEN_8_BIT |
					XUARTPS_MR_STOPMODE_1_BIT |
					XUARTPS_MR_PARITY_NONE);

	/*
	 * Write the mode register out
	 */
	XUartPs_WriteReg(InstancePtr->Config.BaseAddress, XUARTPS_MR_OFFSET,
			   ModeRegister);

	/*
	 * Set the RX FIFO trigger at 8 data bytes.
	 */
	XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
			   XUARTPS_RXWM_OFFSET, 0x08);

	/*
	 * Set the RX timeout to 1, which will be 4 character time
	 */
	XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
			   XUARTPS_RXTOUT_OFFSET, 0x01);

	/*
	 * Disable all interrupts, polled mode is the default
	 */
	XUartPs_WriteReg(InstancePtr->Config.BaseAddress, XUARTPS_IDR_OFFSET,
			   XUARTPS_IXR_MASK);

	return XST_SUCCESS;
}

/****************************************************************************/
/**
*
* This functions sends the specified buffer using the device in either
* polled or interrupt driven mode. This function is non-blocking, if the device
* is busy sending data, it will return and indicate zero bytes were sent.
* Otherwise, it fills the TX FIFO as much as it can, and return the number of
* bytes sent.
*
* In a polled mode, this function will only send as much data as TX FIFO can
* buffer. The application may need to call it repeatedly to send the entire
* buffer.
*
* In interrupt mode, this function will start sending the specified buffer,
* then the interrupt handler will continue sending data until the entire
* buffer has been sent. A callback function, as specified by the application,
* will be called to indicate the completion of sending.
*
* @param	InstancePtr is a pointer to the XUartPs instance.
* @param	BufferPtr is pointer to a buffer of data to be sent.
* @param  	NumBytes contains the number of bytes to be sent. A value of
*		zero will stop a previous send operation that is in progress
*		in interrupt mode. Any data that was already put into the
*		transmit FIFO will be sent.
*
* @return	The number of bytes actually sent.
*
* @note
*
* The number of bytes is not asserted so that this function may be called with
* a value of zero to stop an operation that is already in progress.
* <br><br>
*
*****************************************************************************/
unsigned int XUartPs_Send(XUartPs *InstancePtr, u8 *BufferPtr,
			   unsigned int NumBytes)
{
	unsigned int BytesSent;

	/*
	 * Asserts validate the input arguments
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(BufferPtr != NULL);
	Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Disable the UART transmit interrupts to allow this call to stop a
	 * previous operation that may be interrupt driven.
	 */
	XUartPs_WriteReg(InstancePtr->Config.BaseAddress, XUARTPS_IDR_OFFSET,
					  (XUARTPS_IXR_TXEMPTY | XUARTPS_IXR_TXFULL));

	/*
	 * Setup the buffer parameters
	 */
	InstancePtr->SendBuffer.RequestedBytes = NumBytes;
	InstancePtr->SendBuffer.RemainingBytes = NumBytes;
	InstancePtr->SendBuffer.NextBytePtr = BufferPtr;

	/*
	 * Transmit interrupts will be enabled in XUartPs_SendBuffer(), after
	 * filling the TX FIFO.
	 */
	BytesSent = XUartPs_SendBuffer(InstancePtr);

	return BytesSent;
}

/****************************************************************************/
/**
*
* This function attempts to receive a specified number of bytes of data
* from the device and store it into the specified buffer. This function works
* for both polled or interrupt driven modes. It is non-blocking.
*
* In a polled mode, this function will only receive the data already in the
* RX FIFO. The application may need to call it repeatedly to receive the
* entire buffer. Polled mode is the default mode of operation for the device.
*
* In interrupt mode, this function will start the receiving, if not the entire
* buffer has been received, the interrupt handler will continue receiving data
* until the entire buffer has been received. A callback function, as specified
* by the application, will be called to indicate the completion of the
* receiving or error conditions.
*
* @param	InstancePtr is a pointer to the XUartPs instance
* @param	BufferPtr is pointer to buffer for data to be received into
* @param	NumBytes is the number of bytes to be received. A value of zero
*		will stop a previous receive operation that is in progress in
*		interrupt mode.
*
* @return	The number of bytes received.
*
* @note
*
* The number of bytes is not asserted so that this function may be called
* with a value of zero to stop an operation that is already in progress.
*
*****************************************************************************/
unsigned int XUartPs_Recv(XUartPs *InstancePtr,
			   u8 *BufferPtr, unsigned int NumBytes)
{
	unsigned int ReceivedCount;
	u32 ImrRegister;

	/*
	 * Assert validates the input arguments