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*
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*
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******************************************************************************/
/****************************************************************************/
/**
*
* @file xuartns550.c
*
* This file contains the required functions for the 16450/16550 UART driver.
* Refer to the header file xuartns550.h for more detailed information.
*
*
* MODIFICATION HISTORY:
*
* Ver Who Date Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a ecm 08/16/01 First release
* 1.00b jhl 03/11/02 Repartitioned driver for smaller files.
* 1.00b rmm 05/14/03 Fixed diab compiler warnings relating to asserts.
* 1.01a jvb 12/13/05 I changed Initialize() into CfgInitialize(), and made
* CfgInitialize() take a pointer to a config structure
* instead of a device id. I moved Initialize() into
* xgpio_sinit.c, and had Initialize() call CfgInitialize()
* after it retrieved the config structure using the device
* id. I removed include of xparameters.h along with any
* dependencies on xparameters.h and the _g.c config table.
* 1.11a sv 03/20/07 Updated to use the new coding guidelines.
* 2.00a ktn 10/20/09 Converted all register accesses to 32 bit access.
* Updated to use HAL Processor APIs. _m is removed from the
* name of all the macro definitions. XUartNs550_mClearStats
* macro is removed, XUartNs550_ClearStats function should be
* used in its place.
* 2.01a bss 01/13/12 Removed unneccessary read of the LCR register in the
* XUartNs550_CfgInitialize function. Removed compiler
* warnings for unused variables in the
* XUartNs550_StubHandler.
*
*
*****************************************************************************/
/***************************** Include Files ********************************/
#include "xstatus.h"
#include "xuartns550.h"
#include "xuartns550_i.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 XUN_MAX_BAUD_ERROR_RATE 3 /* max % error allowed */
/**************************** Type Definitions ******************************/
/***************** Macros (Inline Functions) Definitions ********************/
/************************** Variable Definitions ****************************/
/************************** Function Prototypes *****************************/
static void XUartNs550_StubHandler(void *CallBackRef, u32 Event,
unsigned int ByteCount);
/****************************************************************************/
/**
*
* Initializes a specific XUartNs550 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. If the
* device has FIFOs (16550), they are enabled and the a 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 XUartNs550 instance.
* @param Config is a reference to a structure containing information
* about a specific UART 16450/16550 device. XUartNs550_Init
* initializes an InstancePtr object for a specific device
* specified by the contents f Config. XUartNs550_Init can
* initialize multiple instance objects with the use of multiple
* calls giving different Config information on each call.
* @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,
* use Config->BaseAddress for this parameters, passing the
* physical address instead.
*
* @return
* - XST_SUCCESS if initialization was successful.
* - XST_UART_BAUD_ERROR if the baud rate is not possible because
* the input clock frequency is not divisible with an acceptable
* amount of error.
*
* @note None.
*
*****************************************************************************/
int XUartNs550_CfgInitialize(XUartNs550 *InstancePtr,
XUartNs550_Config *Config,
u32 EffectiveAddr)
{
int Status;
u32 BaudRate;
/*
* Assert validates the input arguments
*/
Xil_AssertNonvoid(InstancePtr != NULL);
/*
* Setup the data that is from the configuration information
*/
InstancePtr->BaseAddress = EffectiveAddr;
InstancePtr->InputClockHz = Config->InputClockHz;
/*
* Initialize the instance data to some default values and setup
* a default handler
*/
InstancePtr->Handler = XUartNs550_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;
/*
* Indicate the instance is now ready to use, initialized without error
*/
InstancePtr->IsReady = XIL_COMPONENT_IS_READY;
/*
* Set the default Baud rate here, can be changed prior to
* starting the device
*/
BaudRate = Config->DefaultBaudRate;
if (! BaudRate) {
BaudRate = 19200;
}
Status = XUartNs550_SetBaudRate(InstancePtr, BaudRate);
if (Status != XST_SUCCESS) {
InstancePtr->IsReady = 0;
return Status;
}
/*
* Set up the default format for the data, 8 bit data, 1 stop bit,
* no parity
*/
XUartNs550_SetLineControlReg(InstancePtr->BaseAddress,
XUN_FORMAT_8_BITS);
/*
* Enable the FIFOs assuming they are present and set the receive FIFO
* trigger level for 8 bytes assuming that this will work best with most
* baud rates, enabling the FIFOs also clears them, note that this must
* be done with 2 writes, 1st enabling the FIFOs then set the trigger
* level
*/
XUartNs550_WriteReg(InstancePtr->BaseAddress,
XUN_FCR_OFFSET, XUN_FIFO_ENABLE);
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_FCR_OFFSET,
XUN_FIFO_ENABLE | XUN_FIFO_RX_TRIG_MSB);
/*
* Clear the statistics for this driver
*/
XUartNs550_ClearStats(InstancePtr);
return XST_SUCCESS;
}
/****************************************************************************/
/**
*
* This functions sends the specified buffer of data using the UART in either
* polled or interrupt driven modes. This function is non-blocking such that it
* will return before the data has been sent by the UART. If the UART is busy
* sending data, it will return and indicate zero bytes were sent.
*
* In a polled mode, this function will only send as much data as the UART can
* buffer, either in the transmitter or in the FIFO if present and enabled. The
* application may need to call it repeatedly to send a buffer.
*
* In interrupt mode, this function will start sending the specified buffer and
* then the interrupt handler of the driver will continue sending data until the
* buffer has been sent. A callback function, as specified by the application,
* will be called to indicate the completion of sending the buffer.
*
* @param InstancePtr is a pointer to the XUartNs550 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.
*
* This function and the XUartNs550_SetOptions() function modify shared data
* such that there may be a need for mutual exclusion in a multithreaded
* environment and if XUartNs550_SetOptions() if called from a handler.
*
*****************************************************************************/
unsigned int XUartNs550_Send(XUartNs550 *InstancePtr, u8 *BufferPtr,
unsigned int NumBytes)
{
unsigned int BytesSent;
u32 IerRegister;
/*
* Assert validates the input arguments
*/
Xil_AssertNonvoid(InstancePtr != NULL);
Xil_AssertNonvoid(BufferPtr != NULL);
Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
Xil_AssertNonvoid(((signed)NumBytes) >= 0);
/*
* Enter a critical region by disabling the UART transmit interrupts to
* allow this call to stop a previous operation that may be interrupt
* driven, only stop the transmit interrupt since this critical region
* is not really exited in the normal manner
*/
IerRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_IER_OFFSET);
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET,
IerRegister & ~XUN_IER_TX_EMPTY);
/*
* Setup the specified buffer to be sent by setting the instance
* variables so it can be sent with polled or interrupt mode
*/
InstancePtr->SendBuffer.RequestedBytes = NumBytes;
InstancePtr->SendBuffer.RemainingBytes = NumBytes;
InstancePtr->SendBuffer.NextBytePtr = BufferPtr;
/*
* Send the buffer using the UART and return the number of bytes sent
*/
BytesSent = XUartNs550_SendBuffer(InstancePtr);
/*
* The critical region is not exited in this function because of the way
* the transmit interrupts work. The other function called enables the
* tranmit interrupt such that this function can't restore a value to
* the interrupt enable register and does not need to exit the critical
* region
*/
return BytesSent;
}
/****************************************************************************/
/**
*
* This function will attempt to receive a specified number of bytes of data
* from the UART 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 no data has already received by the UART.
*
* In a polled mode, this function will only receive as much data as the UART
* can buffer, either in the receiver or in the FIFO if present and enabled.
* 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 receiving data 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 XUartNs550 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 XUartNs550_Recv(XUartNs550 *InstancePtr, u8 *BufferPtr,
unsigned int NumBytes)
{
unsigned int ReceivedCount;
u32 IerRegister;
/*
* Assert validates the input arguments
*/
Xil_AssertNonvoid(InstancePtr != NULL);
Xil_AssertNonvoid(BufferPtr != NULL);
Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
Xil_AssertNonvoid(((signed)NumBytes) >= 0);
/*
* Enter a critical region by disabling all the UART interrupts to allow
* this call to stop a previous operation that may be interrupt driven
*/
IerRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_IER_OFFSET);
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET, 0);
/*
* Setup the specified buffer to be received by setting the instance
* variables so it can be received with polled or interrupt mode
*/
InstancePtr->ReceiveBuffer.RequestedBytes = NumBytes;
InstancePtr->ReceiveBuffer.RemainingBytes = NumBytes;
InstancePtr->ReceiveBuffer.NextBytePtr = BufferPtr;
/*
* Receive the data from the UART and return the number of bytes
* received
*/
ReceivedCount = XUartNs550_ReceiveBuffer(InstancePtr);
/*
* Restore the interrupt enable register to it's previous value such
* that the critical region is exited
*/
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET,
IerRegister);
return ReceivedCount;
}
/****************************************************************************/
/**
*
* This function sends 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 XUartNs550 component such that it may be called
* from a shell function that sets up the buffer or from an interrupt handler.
*
* This function sends the specified buffer of data to the UART in either
* polled or interrupt driven modes. This function is non-blocking such that
* it will return before the data has been sent by the UART.
*
* In a polled mode, this function will only send as much data as the UART can
* buffer, either in the transmitter or in the FIFO if present and enabled.
* The application may need to call it repeatedly to send a buffer.
*
* In interrupt mode, this function will start sending the specified buffer and
* then the interrupt handler of the driver will continue until the buffer
* has been sent. A callback function, as specified by the application, will
* be called to indicate the completion of sending the buffer.
*
* @param InstancePtr is a pointer to the XUartNs550 instance.
*
* @return NumBytes is the number of bytes actually sent (put into the
* UART tranmitter and/or FIFO).
*
* @note None.
*
*****************************************************************************/
unsigned int XUartNs550_SendBuffer(XUartNs550 *InstancePtr)
{
unsigned int SentCount = 0;
unsigned int BytesToSend = 0; /* default to not send anything */
unsigned int FifoSize;
u32 LsrRegister;
u32 IirRegister;
u32 IerRegister;
/*
* Read the line status register to determine if the transmitter is
* empty
*/
LsrRegister = XUartNs550_GetLineStatusReg(InstancePtr->BaseAddress);
/*
* If the transmitter is not empty then don't send any data, the empty
* room in the FIFO is not available
*/
if (LsrRegister & XUN_LSR_TX_BUFFER_EMPTY) {
/*
* Read the interrupt ID register to determine if FIFOs
* are enabled
*/
IirRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_IIR_OFFSET);
/*
* When there are FIFOs, send up to the FIFO size. When there
* are no FIFOs, only send 1 byte of data
*/
if (IirRegister & XUN_INT_ID_FIFOS_ENABLED) {
/*
* Determine how many bytes can be sent depending on if
* the transmitter is empty, a FIFO size of N is really
* N - 1 plus the transmitter register
*/
if (LsrRegister & XUN_LSR_TX_EMPTY) {
FifoSize = XUN_FIFO_SIZE;
} else {
FifoSize = XUN_FIFO_SIZE - 1;
}
/*
* FIFOs are enabled, if the number of bytes to send
* is less than the size of the FIFO, then send all
* bytes, otherwise fill the FIFO
*/
if (InstancePtr->SendBuffer.RemainingBytes < FifoSize) {
BytesToSend =
InstancePtr->SendBuffer.RemainingBytes;
} else {
BytesToSend = FifoSize;
}
} else if (InstancePtr->SendBuffer.RemainingBytes > 0) {
/*
* Without FIFOs, we can only send 1 byte. We needed to
* check for non-zero remaining bytes in case this
* routine was called only to kick the transmitter and
* enable the UART interrupt
*/
BytesToSend = 1;
}
/*
* Fill the FIFO if it's present or the transmitter only from
* the the buffer that was specified
*/
for (SentCount = 0; SentCount < BytesToSend; SentCount++) {
XUartNs550_WriteReg(InstancePtr->BaseAddress,
XUN_THR_OFFSET,
InstancePtr->SendBuffer.NextBytePtr[SentCount]);
}
}
/*
* Update the buffer to reflect the bytes that were sent from it
*/
InstancePtr->SendBuffer.NextBytePtr += SentCount;
InstancePtr->SendBuffer.RemainingBytes -= SentCount;
/*
* Increment associated counters
*/
InstancePtr->Stats.CharactersTransmitted += SentCount;
/*
* If interrupts are enabled as indicated by the receive interrupt, then
* enable the transmit interrupt, it is not enabled continuously because
* it causes an interrupt whenever the FIFO is empty
*/
IerRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_IER_OFFSET);
if (IerRegister & XUN_IER_RX_DATA) {
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET,
IerRegister | XUN_IER_TX_EMPTY);
}
/*
* Return the number of bytes that were sent, althought they really were
* only put into the FIFO, not completely sent yet
*/
return SentCount;
}
/****************************************************************************/
/**
*
* 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 XUartNs550 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 the UART 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 by the
* UART.
*
* In a polled mode, this function will only receive as much data as the UART
* can buffer, either in the receiver or in the FIFO if present and enabled.
* 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 XUartNs550 instance.
*
* @return The number of bytes received.
*
* @note None.
*
*****************************************************************************/
unsigned int XUartNs550_ReceiveBuffer(XUartNs550 *InstancePtr)
{
u32 LsrRegister;
unsigned int ReceivedCount = 0;
/*
* Loop until there is not more data buffered by the UART or the
* specified number of bytes is received
*/
while (ReceivedCount < InstancePtr->ReceiveBuffer.RemainingBytes) {
/*
* Read the Line Status Register to determine if there is any
* data in the receiver/FIFO
*/
LsrRegister =
XUartNs550_GetLineStatusReg(InstancePtr->BaseAddress);
/*
* If there is a break condition then a zero data byte was put
* into the receiver, just read it and dump it and update the
* stats
*/
if (LsrRegister & XUN_LSR_BREAK_INT) {
(void)XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_RBR_OFFSET);
XUartNs550_UpdateStats(InstancePtr, (u8)LsrRegister);
}
/*
* If there is data ready to be removed, then put the next byte
* received into the specified buffer and update the stats to
* reflect any receive errors for the byte
*/
else if (LsrRegister & XUN_LSR_DATA_READY) {
InstancePtr->ReceiveBuffer.NextBytePtr[ReceivedCount++] =
XUartNs550_ReadReg(InstancePtr->BaseAddress,
XUN_RBR_OFFSET);
XUartNs550_UpdateStats(InstancePtr, (u8)LsrRegister);
}
/*
* There's 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;
/*
* Increment associated counters in the statistics
*/
InstancePtr->Stats.CharactersReceived += ReceivedCount;
return ReceivedCount;
}
/****************************************************************************
*
* Sets the baud rate for the specified UART. Checks the input value for
* validity and also verifies that the requested rate can be configured to
* within the 3 percent error range for RS-232 communications. If the provided
* rate is not valid, the current setting is unchanged.
*
* This function is designed to be an internal function only used within the
* XUartNs550 component. It is necessary for initialization and for the user
* available function that sets the data format.
*
* @param InstancePtr is a pointer to the XUartNs550 instance.
* @param BaudRate to be set in the hardware.
*
* @return
* - XST_SUCCESS if everything configures as expected
* - XST_UART_BAUD_ERROR if the requested rate is not available
* because there was too much error due to the input clock
*
* @note None.
*
*****************************************************************************/
int XUartNs550_SetBaudRate(XUartNs550 *InstancePtr, u32 BaudRate)
{
u32 BaudLSB;
u32 BaudMSB;
u32 LcrRegister;
u32 Divisor;
u32 TargetRate;
u32 Error;
u32 PercentError;
/*
* Assert validates the input arguments
*/
Xil_AssertNonvoid(InstancePtr != NULL);
Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
/*
* Determine what the divisor should be to get the specified baud
* rater based upon the input clock frequency and a baud clock prescaler
* of 16
*/
Divisor = InstancePtr->InputClockHz / (BaudRate * 16UL);
/*
* check for too much error between the baud rate that will be generated
* using the divisor and the expected baud rate, integer division also
* truncates always positive
*/
TargetRate = Divisor * BaudRate * 16UL;
Error = InstancePtr->InputClockHz - TargetRate;
/*
* Error has total error now compute the percentage multiplied by 100 to
* avoid floating point calculations, should be less than 3% as per
* RS-232 spec
*/
PercentError = (Error * 100UL) / InstancePtr->InputClockHz;
if (PercentError > XUN_MAX_BAUD_ERROR_RATE) {
return XST_UART_BAUD_ERROR;
}
/*
* Get the least significant and most significant bytes of the divisor
* so they can be written to 2 byte registers
*/
BaudLSB = Divisor & XUN_DIVISOR_BYTE_MASK;
BaudMSB = (Divisor >> 8) & XUN_DIVISOR_BYTE_MASK;
/*
* Save the baud rate in the instance so that the get baud rate function
* won't have to calculate it from the divisor
*/
InstancePtr->BaudRate = BaudRate;
/*
* Get the line control register contents and set the divisor latch
* access bit so the baud rate can be set
*/
LcrRegister = XUartNs550_GetLineControlReg(InstancePtr->BaseAddress);
XUartNs550_SetLineControlReg(InstancePtr->BaseAddress ,
LcrRegister | XUN_LCR_DLAB);
/*
* Set the baud Divisors to set rate, the initial write of 0xFF is
* to keep the divisor from being 0 which is not recommended as per
* the NS16550D spec sheet
*/
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_DRLS_OFFSET, 0xFF);
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_DRLM_OFFSET,
BaudMSB);
XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_DRLS_OFFSET,
BaudLSB);
/*
* Clear the Divisor latch access bit, DLAB to allow nornal
* operation and write to the line control register
*/
XUartNs550_SetLineControlReg(InstancePtr->BaseAddress, LcrRegister);
return XST_SUCCESS;
}
/****************************************************************************/
/**
*
* This function is a stub handler that is the default handler such that if the
* application has not set the handler when interrupts are enabled, this
* function will be called. The function interface has to match the interface
* specified for a handler even though none of the arguments are used.
*
* @param CallBackRef is unused by this function.
* @param Event is unused by this function.
* @param ByteCount is unused by this function.
*
* @return None.
*
* @note None.
*
*****************************************************************************/
static void XUartNs550_StubHandler(void *CallBackRef, u32 Event,
unsigned int ByteCount)
{
(void) CallBackRef;
(void) Event;
(void) ByteCount;
/*
* Assert occurs always since this is a stub and should never be called
*/
Xil_AssertVoidAlways();
}