인터럽트 컨트롤러

• In this chapter, I will write Interrupt controler init code and handler mapping code.
• My system starts from Entry.S to main function in main.c. Therefore I'll add spinning section (while loop) in main function after CH3~ CH5 settings for checking Interrupt to work well.

#include "stdint.h"
#include "HalUart.h"
#include "stdio.h"

static void Hw_init();

void main(void){
	Hw_init();
	
	uint32_t i= 100;
	while(i--){
		Hal_uart_put_char('N');
	}
	putstr("\n");
	
	putstr("Jello world\n");			
	i=10;
	
	char *str = "hihi first printf";
	debug_printf("%u: %x %s\n",1,14,str);
	
	while(i--){
		uint8_t c= Hal_uart_get_char();
		
		Hal_uart_put_char(c);
	}
    
    while(true); // add here!
}


static void Hw_init(){
	Hal_uart_init();
}

• I'm done settings, so I'll start Interrupt controler coding.

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데이터시트

• RealviewPB has an Interrupt controler named GIC. At now, I examin the GIC register and make a GIC struct.

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CPU control register

typedef union CpuControl_t
{
    uint32_t all;
    struct {
        uint32_t Enable:1;          // 0
        uint32_t reserved:31;
    } bits;
} CpuControl_t;

• [31:1]
  - reserved
• [0]
  - b0 = disable the CPU interface for this GIC
  - b1 = enable the CPU interface for this GIC

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Priority Mask register.

typedef union PriorityMask_t
{
    uint32_t all;
    struct {
        uint32_t Reserved:4;        // 3:0
        uint32_t Prioritymask:4;    // 7:4
        uint32_t reserved:24;
    } bits;
} PriorityMask_t;

• The CPU Interface doesn't receive an Interrupt request if the priority of the Interrupt is equel to or greater than the mask set.
• [31:8]
  - reserved
• [7:4]
  -Priority Mask
• [3:0]
  - reserved
  

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BInsry Printer register

typedef union BinaryPoint_t
{
    uint32_t all;
    struct {
        uint32_t Binarypoint:3;     // 2:0
        uint32_t reserved:29;
    } bits;
} BinaryPoint_t;

• For the purpose of establishing the pre-emption criteria between Interrupts.
• [31:3]
  - reserved
• [2:0]
  - The criteria of comparing priority for pre-emption.
  • b011 : All priority bits are compared for pre-emption.
  • b100 : Only bits [7:5] of priority are compared.
  • b101 : Only bits [7:6] are compared.
  • b110 : Only bits [7] are.
  • b111 : No pre-emption is perfomed between Interrupts.

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Interrupt acknowledge register

typedef union InterruptAck_t
{
    uint32_t all;
    struct {
        uint32_t InterruptID:10;    // 9:0
        uint32_t CPUsourceID:3;     // 12:10
        uint32_t reserved:19;
    } bits;
} InterruptAck_t;

• The cpu acuire the interrupt number by reading this register
• [31:13]
  - reserved
• [12:10]
  - CPU ID, reserved for multi processor.
• [9:0]
  - The Interrupt number, read only.

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End of Interrupt register

typedef union EndOfInterrupt_t
{
    uint32_t all;
    struct {
        uint32_t InterruptID:10;    // 9:0
        uint32_t CPUsourceID:3;     // 12:10
        uint32_t reserved:19;
    } bits;
} EndOfInterrupt_t;

• When the Interrupt complete its works, it writes the Interrupt number to this register.