Lab 5: Simulated Interrupt Example
Raw: xintc_example.c
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/******************************************************************************
*
* @file xintc_example.c
*
* This file contains a design example using the Interrupt Controller driver
* (XIntc) and hardware device. Please reference other device driver examples to
* see more examples of how the intc and interrupts can be used by a software
* application.
*
* This example shows the use of the Interrupt Controller both with a PowerPC
* and MicroBlaze processor.
*
* Revision:
*
* Author: Tendayi Kamucheka (ftendayi@gmail.com)
* Date: 09/26/2024
* Changes:
* - Replaced XPAR_INTC_0_DEVICE_ID with constant (0) since
* param no longer generated by default in `xparameters.h`.
* - Added notes to clarify XIntc API usage and behaviours.
******************************************************************************/
/***************************** Include Files *********************************/
#include "xparameters.h"
#include "xstatus.h"
#include "xintc.h"
#include "xil_exception.h"
#include "xil_printf.h"
#include "xil_types.h"
/************************** Constant Definitions *****************************/
/*
* Under the hood, the tools create a list of all Interrupt controllers
* present in the block design. In our case, there's only one present
* (axi_intc_0), the device id will be (0).
*/
#define INTC_DEVICE_ID 0
/*
* This is the Interrupt Number of the Device whose Interrupt Output is
* connected to the Input of the Interrupt Controller.
* - Even though we're only simulating the interrupt with this example,
* we'll connect the Interrupt controller to AXI_GPIO_0.
* - The interrupt id we're using came from `xparameters.h`. These ids
* are generated based the order you connected your interrupt sources
* to the Concat IP.
* i.e.:
*
* (0) axi_timer_0 ---\
* ---> Concat ---> axi_intc_0
* (1) axi_gpio_0 ---/
*/
#define INTC_DEVICE_INT_ID XPAR_FABRIC_XGPIO_0_INTR
/**************************** Type Definitions *******************************/
/***************** Macros (Inline Functions) Definitions *********************/
/************************** Function Prototypes ******************************/
int IntcExample(u16 DeviceId);
int SetUpInterruptSystem(XIntc *XIntcInstancePtr);
void DeviceDriverHandler(void *CallbackRef);
/************************** Variable Definitions *****************************/
static XIntc InterruptController; /* Instance of the Interrupt Controller */
/*
* Create a shared variable to be used by the main thread of processing and
* the interrupt processing
*/
volatile static int InterruptProcessed = FALSE;
/*****************************************************************************/
/**
*
* This is the main function for the Interrupt Controller example.
*
* @param None.
*
* @return XST_SUCCESS to indicate success, otherwise XST_FAILURE.
*
* @note None.
*
****************************************************************************/
int main(void)
{
int Status;
/*
* Run the Intc example , specify the Device ID generated in
* xparameters.h
*/
Status = IntcExample(INTC_DEVICE_ID);
if (Status != XST_SUCCESS)
{
xil_printf("Intc Example Failed\r\n");
return XST_FAILURE;
}
xil_printf("Successfully ran Intc Example\r\n");
return XST_SUCCESS;
}
/*****************************************************************************/
/**
*
* This function is an example of how to use the interrupt controller driver
* component (XIntc) and the hardware device. This function is designed to
* work without any hardware devices to cause interrupts. It may not return
* if the interrupt controller is not properly connected to the processor in
* either software or hardware.
*
* This function relies on the fact that the interrupt controller hardware
* has come out of the reset state such that it will allow interrupts to be
* simulated by the software.
*
* @param DeviceId is Device ID of the Interrupt Controller Device,
* typically XPAR_<INTC_instance>_DEVICE_ID value from xparameters.h.
* NB: XPAR_<INTC_instance>_DEVICE_ID is NOT defined in xparameters.h.
*
* @return XST_SUCCESS to indicate success, otherwise XST_FAILURE.
*
* @note Since the device id was not automatically generated, we defined if
* above as XINC_DEVICE_ID = 0.
*
******************************************************************************/
int IntcExample(u16 DeviceId)
{
int Status;
/*
* Initialize the interrupt controller driver so that it is ready to
* use.
*
* NB: The device id is used to determine which interrupt controller
* to initialize. This is only necessary when there are multiple
* interrupt controllers present in the block design. Here,
* we're only using one interrupt controller, so the device id
* is set to 0.
*/
Status = XIntc_Initialize(&InterruptController, DeviceId);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Perform a self-test to ensure that the hardware was built
* correctly.
*/
Status = XIntc_SelfTest(&InterruptController);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Setup the Interrupt System.
*/
Status = SetUpInterruptSystem(&InterruptController);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Simulate the Interrupt.
*/
Status = XIntc_SimulateIntr(&InterruptController, INTC_DEVICE_INT_ID);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Wait for the interrupt to be processed, if the interrupt does not
* occur this loop will wait forever.
* NB: The software interrupt has already been triggered by the call to
* `XIntc_SimulateIntr` above and the connected interrupt handler
* has already set InterruptProcessed = TRUE.
*/
while (1)
{
/*
* If the interrupt occurred which is indicated by the global
* variable which is set in the device driver handler, then
* stop waiting.
*/
if (InterruptProcessed)
{
break;
}
}
return XST_SUCCESS;
}
/******************************************************************************/
/**
*
* This function connects the interrupt handler of the interrupt controller to
* the processor. This function is separate to allow it to be customized for
* each application. Each processor or RTOS may require unique processing to
* connect the interrupt handler.
*
* @param None.
*
* @return None.
*
* @note None.
*
****************************************************************************/
int SetUpInterruptSystem(XIntc *XIntcInstancePtr)
{
int Status;
/*
* Connect a device driver handler that will be called when an interrupt
* for the device occurs, the device driver handler performs the
* specific interrupt processing for the device.
*/
Status = XIntc_Connect(XIntcInstancePtr, INTC_DEVICE_INT_ID,
(XInterruptHandler)DeviceDriverHandler,
(void *)0);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Start the interrupt controller such that interrupts are enabled for
* all devices that cause interrupts, specify simulation mode so that
* an interrupt can be caused by software rather than a real hardware
* interrupt.
*/
Status = XIntc_Start(XIntcInstancePtr, XIN_SIMULATION_MODE);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
/*
* Enable the interrupt for the device and then cause (simulate) an
* interrupt so the handlers will be called.
*/
XIntc_Enable(XIntcInstancePtr, INTC_DEVICE_INT_ID);
/*
* Initialize the exception table.
*/
Xil_ExceptionInit();
/*
* Register the interrupt controller handler with the exception table.
*/
Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
(Xil_ExceptionHandler)XIntc_InterruptHandler,
XIntcInstancePtr);
/*
* Enable exceptions.
*/
Xil_ExceptionEnable();
return XST_SUCCESS;
}
/******************************************************************************/
/**
*
* This function is designed to look like an interrupt handler in a device
* driver. This is typically a 2nd level handler that is called from the
* interrupt controller interrupt handler. This handler would typically
* perform device specific processing such as reading and writing the registers
* of the device to clear the interrupt condition and pass any data to an
* application using the device driver. Many drivers already provide this
* handler and the user is not required to create it.
*
* @param CallbackRef is passed back to the device driver's interrupt
* handler by the XIntc driver. It was given to the XIntc driver
* in the XIntc_Connect() function call. It is typically a pointer
* to the device driver instance variable if using the Xilinx
* Level 1 device drivers. In this example, we do not care about
* the callback reference, so we passed it a 0 when connecting the
* handler to the XIntc driver and we make no use of it here.
*
* @return None.
*
* @note None.
*
****************************************************************************/
void DeviceDriverHandler(void *CallbackRef)
{
/*
* Indicate the interrupt has been processed using a shared variable.
*/
InterruptProcessed = TRUE;
xil_printf("Interrupt occurred!\n");
}