2c8f92039d
Added initial support Xilinx Embedded Software. Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
743 lines
26 KiB
C
Executable file
743 lines
26 KiB
C
Executable file
/******************************************************************************
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*
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* Copyright (C) 2002 - 2014 Xilinx, Inc. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* Use of the Software is limited solely to applications:
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* (a) running on a Xilinx device, or
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* (b) that interact with a Xilinx device through a bus or interconnect.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* XILINX CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
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* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* Except as contained in this notice, the name of the Xilinx shall not be used
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* in advertising or otherwise to promote the sale, use or other dealings in
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* this Software without prior written authorization from Xilinx.
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*
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******************************************************************************/
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/****************************************************************************/
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/**
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*
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* @file xuartns550.c
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*
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* This file contains the required functions for the 16450/16550 UART driver.
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* Refer to the header file xuartns550.h for more detailed information.
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*
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* <pre>
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* MODIFICATION HISTORY:
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*
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* Ver Who Date Changes
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* ----- ---- -------- -----------------------------------------------
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* 1.00a ecm 08/16/01 First release
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* 1.00b jhl 03/11/02 Repartitioned driver for smaller files.
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* 1.00b rmm 05/14/03 Fixed diab compiler warnings relating to asserts.
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* 1.01a jvb 12/13/05 I changed Initialize() into CfgInitialize(), and made
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* CfgInitialize() take a pointer to a config structure
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* instead of a device id. I moved Initialize() into
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* xgpio_sinit.c, and had Initialize() call CfgInitialize()
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* after it retrieved the config structure using the device
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* id. I removed include of xparameters.h along with any
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* dependencies on xparameters.h and the _g.c config table.
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* 1.11a sv 03/20/07 Updated to use the new coding guidelines.
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* 2.00a ktn 10/20/09 Converted all register accesses to 32 bit access.
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* Updated to use HAL Processor APIs. _m is removed from the
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* name of all the macro definitions. XUartNs550_mClearStats
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* macro is removed, XUartNs550_ClearStats function should be
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* used in its place.
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* 2.01a bss 01/13/12 Removed unneccessary read of the LCR register in the
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* XUartNs550_CfgInitialize function. Removed compiler
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* warnings for unused variables in the
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* XUartNs550_StubHandler.
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* </pre>
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*
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*****************************************************************************/
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/***************************** Include Files ********************************/
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#include "xstatus.h"
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#include "xuartns550.h"
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#include "xuartns550_i.h"
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#include "xil_io.h"
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/************************** Constant Definitions ****************************/
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/* The following constant defines the amount of error that is allowed for
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* a specified baud rate. This error is the difference between the actual
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* baud rate that will be generated using the specified clock and the
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* desired baud rate.
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*/
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#define XUN_MAX_BAUD_ERROR_RATE 3 /* max % error allowed */
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/**************************** Type Definitions ******************************/
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/***************** Macros (Inline Functions) Definitions ********************/
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/************************** Variable Definitions ****************************/
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/************************** Function Prototypes *****************************/
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static void XUartNs550_StubHandler(void *CallBackRef, u32 Event,
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unsigned int ByteCount);
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/****************************************************************************/
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/**
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*
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* Initializes a specific XUartNs550 instance such that it is ready to be used.
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* The data format of the device is setup for 8 data bits, 1 stop bit, and no
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* parity by default. The baud rate is set to a default value specified by
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* Config->DefaultBaudRate if set, otherwise it is set to 19.2K baud. If the
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* device has FIFOs (16550), they are enabled and the a receive FIFO threshold
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* is set for 8 bytes. The default operating mode of the driver is polled mode.
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*
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* @param InstancePtr is a pointer to the XUartNs550 instance.
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* @param Config is a reference to a structure containing information
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* about a specific UART 16450/16550 device. XUartNs550_Init
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* initializes an InstancePtr object for a specific device
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* specified by the contents f Config. XUartNs550_Init can
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* initialize multiple instance objects with the use of multiple
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* calls giving different Config information on each call.
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* @param EffectiveAddr is the device base address in the virtual memory
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* address space. The caller is responsible for keeping the
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* address mapping from EffectiveAddr to the device physical base
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* address unchanged once this function is invoked. Unexpected
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* errors may occur if the address mapping changes after this
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* function is called. If address translation is not used,
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* use Config->BaseAddress for this parameters, passing the
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* physical address instead.
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*
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* @return
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* - XST_SUCCESS if initialization was successful.
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* - XST_UART_BAUD_ERROR if the baud rate is not possible because
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* the input clock frequency is not divisible with an acceptable
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* amount of error.
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*
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* @note None.
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*
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*****************************************************************************/
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int XUartNs550_CfgInitialize(XUartNs550 *InstancePtr,
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XUartNs550_Config *Config,
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u32 EffectiveAddr)
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{
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int Status;
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u32 BaudRate;
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/*
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* Assert validates the input arguments
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*/
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Xil_AssertNonvoid(InstancePtr != NULL);
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/*
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* Setup the data that is from the configuration information
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*/
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InstancePtr->BaseAddress = EffectiveAddr;
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InstancePtr->InputClockHz = Config->InputClockHz;
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/*
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* Initialize the instance data to some default values and setup
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* a default handler
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*/
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InstancePtr->Handler = XUartNs550_StubHandler;
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InstancePtr->SendBuffer.NextBytePtr = NULL;
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InstancePtr->SendBuffer.RemainingBytes = 0;
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InstancePtr->SendBuffer.RequestedBytes = 0;
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InstancePtr->ReceiveBuffer.NextBytePtr = NULL;
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InstancePtr->ReceiveBuffer.RemainingBytes = 0;
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InstancePtr->ReceiveBuffer.RequestedBytes = 0;
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/*
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* Indicate the instance is now ready to use, initialized without error
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*/
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InstancePtr->IsReady = XIL_COMPONENT_IS_READY;
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/*
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* Set the default Baud rate here, can be changed prior to
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* starting the device
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*/
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BaudRate = Config->DefaultBaudRate;
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if (! BaudRate) {
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BaudRate = 19200;
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}
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Status = XUartNs550_SetBaudRate(InstancePtr, BaudRate);
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if (Status != XST_SUCCESS) {
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InstancePtr->IsReady = 0;
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return Status;
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}
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/*
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* Set up the default format for the data, 8 bit data, 1 stop bit,
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* no parity
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*/
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XUartNs550_SetLineControlReg(InstancePtr->BaseAddress,
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XUN_FORMAT_8_BITS);
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/*
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* Enable the FIFOs assuming they are present and set the receive FIFO
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* trigger level for 8 bytes assuming that this will work best with most
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* baud rates, enabling the FIFOs also clears them, note that this must
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* be done with 2 writes, 1st enabling the FIFOs then set the trigger
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* level
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*/
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XUartNs550_WriteReg(InstancePtr->BaseAddress,
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XUN_FCR_OFFSET, XUN_FIFO_ENABLE);
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XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_FCR_OFFSET,
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XUN_FIFO_ENABLE | XUN_FIFO_RX_TRIG_MSB);
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/*
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* Clear the statistics for this driver
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*/
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XUartNs550_ClearStats(InstancePtr);
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return XST_SUCCESS;
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}
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/****************************************************************************/
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/**
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*
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* This functions sends the specified buffer of data using the UART in either
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* polled or interrupt driven modes. This function is non-blocking such that it
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* will return before the data has been sent by the UART. If the UART is busy
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* sending data, it will return and indicate zero bytes were sent.
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*
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* In a polled mode, this function will only send as much data as the UART can
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* buffer, either in the transmitter or in the FIFO if present and enabled. The
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* application may need to call it repeatedly to send a buffer.
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*
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* In interrupt mode, this function will start sending the specified buffer and
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* then the interrupt handler of the driver will continue sending data until the
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* buffer has been sent. A callback function, as specified by the application,
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* will be called to indicate the completion of sending the buffer.
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*
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* @param InstancePtr is a pointer to the XUartNs550 instance.
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* @param BufferPtr is pointer to a buffer of data to be sent.
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* @param NumBytes contains the number of bytes to be sent. A value of
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* zero will stop a previous send operation that is in progress
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* in interrupt mode. Any data that was already put into the
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* transmit FIFO will be sent.
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*
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* @return The number of bytes actually sent.
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*
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* @note
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*
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* The number of bytes is not asserted so that this function may be called with
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* a value of zero to stop an operation that is already in progress.
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* <br><br>
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* This function and the XUartNs550_SetOptions() function modify shared data
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* such that there may be a need for mutual exclusion in a multithreaded
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* environment and if XUartNs550_SetOptions() if called from a handler.
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*
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*****************************************************************************/
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unsigned int XUartNs550_Send(XUartNs550 *InstancePtr, u8 *BufferPtr,
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unsigned int NumBytes)
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{
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unsigned int BytesSent;
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u32 IerRegister;
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/*
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* Assert validates the input arguments
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*/
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Xil_AssertNonvoid(InstancePtr != NULL);
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Xil_AssertNonvoid(BufferPtr != NULL);
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Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
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Xil_AssertNonvoid(((signed)NumBytes) >= 0);
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/*
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* Enter a critical region by disabling the UART transmit interrupts to
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* allow this call to stop a previous operation that may be interrupt
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* driven, only stop the transmit interrupt since this critical region
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* is not really exited in the normal manner
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*/
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IerRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
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XUN_IER_OFFSET);
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XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET,
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IerRegister & ~XUN_IER_TX_EMPTY);
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/*
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* Setup the specified buffer to be sent by setting the instance
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* variables so it can be sent with polled or interrupt mode
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*/
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InstancePtr->SendBuffer.RequestedBytes = NumBytes;
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InstancePtr->SendBuffer.RemainingBytes = NumBytes;
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InstancePtr->SendBuffer.NextBytePtr = BufferPtr;
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/*
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* Send the buffer using the UART and return the number of bytes sent
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*/
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BytesSent = XUartNs550_SendBuffer(InstancePtr);
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/*
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* The critical region is not exited in this function because of the way
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* the transmit interrupts work. The other function called enables the
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* tranmit interrupt such that this function can't restore a value to
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* the interrupt enable register and does not need to exit the critical
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* region
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*/
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return BytesSent;
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}
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/****************************************************************************/
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/**
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*
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* This function will attempt to receive a specified number of bytes of data
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* from the UART and store it into the specified buffer. This function is
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* designed for either polled or interrupt driven modes. It is non-blocking
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* such that it will return if no data has already received by the UART.
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*
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* In a polled mode, this function will only receive as much data as the UART
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* can buffer, either in the receiver or in the FIFO if present and enabled.
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* The application may need to call it repeatedly to receive a buffer. Polled
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* mode is the default mode of operation for the driver.
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*
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* In interrupt mode, this function will start receiving and then the interrupt
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* handler of the driver will continue receiving data until the buffer has been
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* received. A callback function, as specified by the application, will be called
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* to indicate the completion of receiving the buffer or when any receive errors
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* or timeouts occur. Interrupt mode must be enabled using the SetOptions function.
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*
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* @param InstancePtr is a pointer to the XUartNs550 instance.
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* @param BufferPtr is pointer to buffer for data to be received into
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* @param NumBytes is the number of bytes to be received. A value of zero
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* will stop a previous receive operation that is in progress in
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* interrupt mode.
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*
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* @return The number of bytes received.
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*
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* @note
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*
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* The number of bytes is not asserted so that this function may be called with
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* a value of zero to stop an operation that is already in progress.
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*
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*****************************************************************************/
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unsigned int XUartNs550_Recv(XUartNs550 *InstancePtr, u8 *BufferPtr,
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unsigned int NumBytes)
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{
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unsigned int ReceivedCount;
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u32 IerRegister;
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/*
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* Assert validates the input arguments
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*/
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Xil_AssertNonvoid(InstancePtr != NULL);
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Xil_AssertNonvoid(BufferPtr != NULL);
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Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
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Xil_AssertNonvoid(((signed)NumBytes) >= 0);
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/*
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* Enter a critical region by disabling all the UART interrupts to allow
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* this call to stop a previous operation that may be interrupt driven
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*/
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IerRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
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XUN_IER_OFFSET);
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XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET, 0);
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/*
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* Setup the specified buffer to be received by setting the instance
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* variables so it can be received with polled or interrupt mode
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*/
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InstancePtr->ReceiveBuffer.RequestedBytes = NumBytes;
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InstancePtr->ReceiveBuffer.RemainingBytes = NumBytes;
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InstancePtr->ReceiveBuffer.NextBytePtr = BufferPtr;
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/*
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* Receive the data from the UART and return the number of bytes
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* received
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*/
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ReceivedCount = XUartNs550_ReceiveBuffer(InstancePtr);
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/*
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* Restore the interrupt enable register to it's previous value such
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* that the critical region is exited
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*/
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XUartNs550_WriteReg(InstancePtr->BaseAddress, XUN_IER_OFFSET,
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IerRegister);
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return ReceivedCount;
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}
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/****************************************************************************/
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/**
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*
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* This function sends a buffer that has been previously specified by setting
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* up the instance variables of the instance. This function is designed to be
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* an internal function for the XUartNs550 component such that it may be called
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* from a shell function that sets up the buffer or from an interrupt handler.
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*
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* This function sends the specified buffer of data to the UART in either
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* polled or interrupt driven modes. This function is non-blocking such that
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* it will return before the data has been sent by the UART.
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*
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* In a polled mode, this function will only send as much data as the UART can
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* buffer, either in the transmitter or in the FIFO if present and enabled.
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* The application may need to call it repeatedly to send a buffer.
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*
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* In interrupt mode, this function will start sending the specified buffer and
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* then the interrupt handler of the driver will continue until the buffer
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* has been sent. A callback function, as specified by the application, will
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* be called to indicate the completion of sending the buffer.
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*
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* @param InstancePtr is a pointer to the XUartNs550 instance.
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*
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* @return NumBytes is the number of bytes actually sent (put into the
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* UART tranmitter and/or FIFO).
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*
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* @note None.
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*
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*****************************************************************************/
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unsigned int XUartNs550_SendBuffer(XUartNs550 *InstancePtr)
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{
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unsigned int SentCount = 0;
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unsigned int BytesToSend = 0; /* default to not send anything */
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unsigned int FifoSize;
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u32 LsrRegister;
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u32 IirRegister;
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u32 IerRegister;
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/*
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* Read the line status register to determine if the transmitter is
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* empty
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*/
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LsrRegister = XUartNs550_GetLineStatusReg(InstancePtr->BaseAddress);
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/*
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* If the transmitter is not empty then don't send any data, the empty
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* room in the FIFO is not available
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*/
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if (LsrRegister & XUN_LSR_TX_BUFFER_EMPTY) {
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/*
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* Read the interrupt ID register to determine if FIFOs
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* are enabled
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*/
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IirRegister = XUartNs550_ReadReg(InstancePtr->BaseAddress,
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XUN_IIR_OFFSET);
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/*
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* When there are FIFOs, send up to the FIFO size. When there
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* are no FIFOs, only send 1 byte of data
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*/
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if (IirRegister & XUN_INT_ID_FIFOS_ENABLED) {
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/*
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* Determine how many bytes can be sent depending on if
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* the transmitter is empty, a FIFO size of N is really
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* N - 1 plus the transmitter register
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*/
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if (LsrRegister & XUN_LSR_TX_EMPTY) {
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FifoSize = XUN_FIFO_SIZE;
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} else {
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FifoSize = XUN_FIFO_SIZE - 1;
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}
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/*
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* FIFOs are enabled, if the number of bytes to send
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* is less than the size of the FIFO, then send all
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* bytes, otherwise fill the FIFO
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*/
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if (InstancePtr->SendBuffer.RemainingBytes < FifoSize) {
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BytesToSend =
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InstancePtr->SendBuffer.RemainingBytes;
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} else {
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BytesToSend = FifoSize;
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}
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} else if (InstancePtr->SendBuffer.RemainingBytes > 0) {
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/*
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* Without FIFOs, we can only send 1 byte. We needed to
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* check for non-zero remaining bytes in case this
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* routine was called only to kick the transmitter and
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* enable the UART interrupt
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*/
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BytesToSend = 1;
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}
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/*
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* Fill the FIFO if it's present or the transmitter only from
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* the the buffer that was specified
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*/
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for (SentCount = 0; SentCount < BytesToSend; SentCount++) {
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XUartNs550_WriteReg(InstancePtr->BaseAddress,
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XUN_THR_OFFSET,
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InstancePtr->SendBuffer.NextBytePtr[SentCount]);
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}
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}
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/*
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* Update the buffer to reflect the bytes that were sent from it
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*/
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InstancePtr->SendBuffer.NextBytePtr += SentCount;
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InstancePtr->SendBuffer.RemainingBytes -= SentCount;
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/*
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* Increment associated counters
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*/
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InstancePtr->Stats.CharactersTransmitted += SentCount;
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/*
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* If interrupts are enabled as indicated by the receive interrupt, then
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* enable the transmit interrupt, it is not enabled continuously because
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* it causes an interrupt whenever the FIFO is empty
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|
*/
|
|
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();
|
|
}
|
|
|