xscugic_intr.c

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/**
*
* @file xscugic_intr.c
*
* This file contains the interrupt processing for the driver for the Xilinx
* Interrupt Controller.  The interrupt processing is partitioned separately such
* that users are not required to use the provided interrupt processing.  This
* file requires other files of the driver to be linked in also.
*
* The interrupt handler, XScuGic_InterruptHandler, uses an input argument which
* is an instance pointer to an interrupt controller driver such that multiple
* interrupt controllers can be supported.  This handler requires the calling
* function to pass it the appropriate argument, so another level of indirection
* may be required.
*
* The interrupt processing may be used by connecting the interrupt handler to
* the interrupt system.  The handler does not save and restore the processor
* context but only handles the processing of the Interrupt Controller. The user
* is encouraged to supply their own interrupt handler when performance tuning is
* deemed necessary.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- ---------------------------------------------------------
* 1.00a drg  01/19/10 First release
* 1.01a sdm  11/09/11 XScuGic_InterruptHandler has changed correspondingly
*		      since the HandlerTable has now moved to XScuGic_Config.
*
* </pre>
*
* @internal
*
* This driver assumes that the context of the processor has been saved prior to
* the calling of the Interrupt Controller interrupt handler and then restored
* after the handler returns. This requires either the running RTOS to save the
* state of the machine or that a wrapper be used as the destination of the
* interrupt vector to save the state of the processor and restore the state
* after the interrupt handler returns.
*
******************************************************************************/

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

#include "xil_types.h"
#include "xil_assert.h"
#include "xscugic.h"

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

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

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

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

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

/*****************************************************************************/
/**
* This function is the primary interrupt handler for the driver.  It must be
* connected to the interrupt source such that it is called when an interrupt of
* the interrupt controller is active. It will resolve which interrupts are
* active and enabled and call the appropriate interrupt handler. It uses
* the Interrupt Type information to determine when to acknowledge the interrupt.
* Highest priority interrupts are serviced first.
*
* This function assumes that an interrupt vector table has been previously
* initialized.  It does not verify that entries in the table are valid before
* calling an interrupt handler.
*
* This handler also defaults to having nested interrupts disabled. The define
* is XSCUGIC_NESTED_INTERRUPTS and if it is not defined, the option to service
* all of the interrupts is honored. If nested interrupts are enabled, the
* standard interrupt processing will always only service one interrupt and then
* return.
*
* @param	InstancePtr is a pointer to the XScuGic instance.
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
void XScuGic_InterruptHandler(XScuGic *InstancePtr)
{

    u32 IntID;
    XScuGic_VectorTableEntry *TablePtr;

    /* Assert that the pointer to the instance is valid
     */
    Xil_AssertVoid(InstancePtr != NULL);

    /*
     * Read the int_ack register to identify the highest priority interrupt ID
     * and make sure it is valid. Reading Int_Ack will clear the interrupt
     * in the GIC.
     */
    IntID = XScuGic_CPUReadReg(InstancePtr, XSCUGIC_INT_ACK_OFFSET) &
			XSCUGIC_ACK_INTID_MASK;
    if(XSCUGIC_MAX_NUM_INTR_INPUTS < IntID){
	goto IntrExit;
    }

    /*
     * If the interrupt is shared, do some locking here if there are multiple
     * processors.
     */
    /*
     * If pre-eption is required:
     * Re-enable pre-emption by setting the CPSR I bit for non-secure ,
     * interrupts or the F bit for secure interrupts
     */

    /*
     * If we need to change security domains, issue a SMC instruction here.
     */

    /*
     * Execute the ISR. Jump into the Interrupt service routine based on the
     * IRQSource. A software trigger is cleared by the ACK.
     */
        TablePtr = &(InstancePtr->Config->HandlerTable[IntID]);
        TablePtr->Handler(TablePtr->CallBackRef);

IntrExit:
    /*
     * Write to the EOI register, we are all done here.
     * Let this function return, the boot code will restore the stack.
     */
    XScuGic_CPUWriteReg(InstancePtr, XSCUGIC_EOI_OFFSET, IntID);

    /*
     * Return from the interrupt. Change security domains could happen here.
     */
}