irq_ser.c

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/*******************************************************************************
 * 
 * ARM Strategic Support Group
 *
 *******************************************************************************/

/*******************************************************************************
 *
 * Module       : irq_ser.c
 * Description  : Setups Samsung KS32C50100 IRQ registers and services the 
 * 				  IRQ (button interrupt requests)
 * Too Chain	: ARM Developer Suite v1.0
 * Platform     : Evaluator7T
 * History      : 
 *
 * 		980416 ASloss
 *		- added button interrupt service
 *      - added header information
 *		  
 *		980625 ASloss
 *		- irq_installhandler alter to be Load PC compatible	
 *
 *		2000-04-04 Andrew N. Sloss
 *		- port to the Evaluator7T
 *
 * Notes        : Refer to the Samsung KS32C50100 documentation 
 *
 *******************************************************************************/

/*******************************************************************************
 * IMPORT
 *******************************************************************************/

#include <stdio.h>
#include "switch.h"

/*******************************************************************************
 * MACRO'S
 *******************************************************************************/

// -- Samsung KS32C50100............. 

#define SYSCFG                          0x03FF0000
#define IOPMOD                          (SYSCFG + 0x5000)
#define IOPCON                          (SYSCFG + 0x5004)
#define IOPDATA                         (SYSCFG + 0x5008)

#define INTPND							(SYSCFG + 0x4004)
#define INTMSK							(SYSCFG + 0x4008)
#define INT_GLOBAL						(21)

#define INT_SW3_MASK					(1)

#define IO_ENABLE_INT0					(1<<4)
#define IO_ACTIVE_HIGH_INT0				(1<<3)
#define IO_RISING_EDGE_INT0				(1)

// -- Standard Macros...............

#define IRQVector (unsigned *) 0x18
#define PIPE_OFFSET            0x08
#define WORD_OFFSET            0x02
#define CHECK_24_BIT    0xff000000
#define BRANCH_OP_CODE  0xea000000
#define MAX_CT_LOAD		0x0000ffff
#define LOWER_16_MASK	0x0000ffff

/*****************************************************************************
 * EXTERN's
 *****************************************************************************/

extern void handler_irq(void);
extern void SetupSVC(void);
extern int  Angel_IRQ_Address;

/*****************************************************************************
 * STATICS
 *****************************************************************************/

// none...

/*****************************************************************************
 * ROUTINES
 *****************************************************************************/

/* -- irq_installhandler ------------------------------------------------------
 *                                                            
 * Description  : Places a branch instruction for the routine into the defined 
 *                'vector' location - this function returns the original 
 *                contents of the 'vector      
 *
 * Parameters   : unsigned routine - IRQ handler
 *				: unsigned *vector - IRQ vector   
 * Return       : 
 * Notes        : 'routine' MUST BE WITHIN A  RANGE OF 32Mbytes FROM 'vector'
 *                                                                             
 */

static void irq_installhandler (unsigned routine, unsigned *vector) 
{
unsigned old_vector_value = 0;
unsigned *absolute;   
  
   old_vector_value = 0;

	/***********************************************************************	
	 * Now the inverse must be done on the original vector to retrieve the 
	 * Angel IRQ Handler routine .                                                
	 ***********************************************************************/
   
   old_vector_value  = *vector;  	 // Get old vector contents ....................
   old_vector_value ^= 0xe59ff000;	 // Mask off the instruction to get the offset
 
	// ** calculate absolute address

   absolute	     	= (unsigned *) (0x18 + old_vector_value+0x8); 
					// IRQ Address
   Angel_IRQ_Address 	= *absolute; 	// chain Angel Interrupt Handler	  
   *absolute		= routine; 	// IRQ handler

}

/* -- irq_initbutton ---------------------------------------------------------
 *                                                            
 * Description  :  Initialises the button interrupt    
 *
 * Parameters   : none...   
 * Return       : none...
 * Notes        : none...
 *                                                                             
 */

static void irq_initbutton (void)
{

	// unmask the switch interrupt ...........	
	*(volatile int*)INTMSK &= ~((1<<INT_GLOBAL) | (1<<0));   
	
  	*(unsigned *)IOPCON 	|= IO_ENABLE_INT0; 			// enable int0
  	*(unsigned *)IOPCON	|= IO_ACTIVE_HIGH_INT0; 	// set as active high
  	*(unsigned *)IOPCON	|= IO_RISING_EDGE_INT0;		// allow for RISING EDGE
}

/* -- irq_buttonpress -----------------------------------------------------------
 *
 * Description  : handles the button press interrupt...
 *
 * Parameters   : none...
 * Return       : none...
 * Notes        : none...
 *
 */ 

void  irq_buttonpress (void) 
{
   /* Read in the Interrupt source .................................. */

	switch_interrupt();
	
	*(unsigned *) INTPND |= INT_SW3_MASK;
}

/* -- irq_init ----------------------------------------------------------------
 * 
 * Description  : This module is where all system setup would be placed - in 
 *                this case it is only Counter/Timer that we are initialising 
 *                so we only have a routine to initialise this. Also called 
 *                from here is the Interrupt Handler install routine and 
 *                initialize button interrupt
 *
 * Parameters   : none...
 * Return       : none...
 * Notes        : none...
 *
 */

void irq_init (void)
{
	SetupSVC();		/* This is necessary if Angel is not running
				 *  on the target (as when running semi-hosted
				 *  from E-Ice) otherwise, let Angel handle it */

	irq_initbutton ();

	irq_installhandler ((unsigned)handler_irq, IRQVector);
}


/*******************************************************************************
 * END OF irq_ser.c
 *******************************************************************************/