BCM_GPIO驱动测试

/***********************************************************
 * led.c
 * 53344中有16个GPIO，但是却不是在统一个GPIO寄存器中设置的，
 * GPIO0-GPIO3是以CMIC开头的寄存器，
 * GPIO4-GPIO16才是以GPIO开头的寄存器。
 *********************************************************/
typedef     volatile unsigned int U32;

#define     GPIO_INPUT    *(U32 *)0x18000060
#define     GPIO_OUT      *(U32 *)0x18000064
#define     GPIO_OUT_EN   *(U32 *)0x18000068

#define     CMIC_GP_DATA_IN    *(U32 *)0x48002000
#define     CMIC_GP_DATA_OUT   *(U32 *)0x48002004
#define     CMIC_GP_OUT_EN     *(U32 *)0x48002008
#define     CMIC_GP_INT_TYPE   *(U32 *)0x4800200c

void configure_output(int gpio);
void configure_input(int gpio);
void led_on(int gpio);
void led_off(int gpio);
void delay(void);
void delays(int count);

int _start(void)
{
    configure_output(0);
    configure_output(1);
    configure_output(2);

    CMIC_GP_OUT_EN |= 0xf;
    CMIC_GP_DATA_OUT &= ~0xf;

    while (1) {
        led_on(0);
        led_on(1);
        led_on(2);
        delay();
        led_off(0);
        led_off(1);
        led_off(2);
        delay();
    }

    return 0;
}
void configure_output(int gpio)
{
    GPIO_OUT_EN |= (1 << gpio);
}

void configure_input(int gpio)
{
    GPIO_OUT_EN &= ~(1 << gpio);
}

void led_on(int gpio)
{
    GPIO_OUT &= ~(1 << gpio);
}

void led_off(int gpio)
{
    GPIO_OUT |= (1 << gpio);
}

void delay(void)
{
    __asm__ __volatile__ (
    "ldr    r0 , =0x4ffffff \n"
    "delayloop:    \n"
    "subs r0 , r0 , #1      \n"
    "bne    delayloop     \n"
    :::"r0"
    );
}

void delays(int count)
{
    __asm__ __volatile__ (
    "mov    r0 , %0         \n"
    "delaysloop:    \n"
    "subs r0 , r0 , #1      \n"
    "bne    delaysloop     \n"
    ::"r"(count)
    :"r0"
    );

all:
    arm-linux-gcc -c  led.c  -o  led.o -fno-builtin
    arm-linux-ld  -T led.lds  led.o  -o  led
    arm-linux-objcopy -O binary led  led.bin
clean:
    rm -rf led  led.bin   *.o  

arm-linux-ld  -T0x61000000  led.o  -o  led

arm-linux-ld --verbose > led.lds

/* Script for -z combreloc: combine and sort reloc sections */
OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm",
          "elf32-littlearm")
OUTPUT_ARCH(arm)
ENTRY(_start)
SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/lib"); SEARCH_DIR("=/usr/lib");
SECTIONS
{
    . = 0x61000000 ; 　　/*  程序的起始地址 */
    
    .text :
    {   
        led.o(.text) ; 
        *(.text) ; 
    }   
    align = 4 ; 
}

go 0x61000000