mmapped GPIO test

mmapped_oe_test.c

/*
 * memmapped_oe_test.c
 *
 *  Created on: Jun 11, 2013
 *      Author: jacek
 * Compile the code:
 *      gcc memmapped_oe_test.c -o memmapped_oe_test -std=c99
 */

#include <stdint.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>


#define DATA_OUT_REG    0x13C
#define DATA_IN_REG     0x138
#define GPIO_OE_REG     0x134

int main()
{
        const uint32_t gpioAddrs[] =
                { 0x44E07000, 0x4804C000, 0x481AC000, 0x481AE000 };
        uint32_t *gpios[4];
        int gpioFd;

        gpioFd = open("/dev/mem", O_RDWR | O_SYNC);
        for (int i = 0; i < 4; i++)
        {
                gpios[i] = (uint32_t *) mmap(NULL, 0xfff,
                                PROT_READ | PROT_WRITE, MAP_SHARED, gpioFd, gpioAddrs[i]);
                printf("gpio[%i] at address 0x%08x mapped at 0x%08x\n",i,gpioAddrs[i],gpios[i]);
        }

        int i;
        i=0; //Bus error
        //i=1; //OK
        //i=2; //Bus error
        //i=3; //Bus error
        printf("i=%i\n",i);
        printf("OUT[%i]=0x%08x\n",i,gpios[i][DATA_OUT_REG/4]);
        printf("IN[%i]=0x%08x\n",i,gpios[i][DATA_IN_REG/4]);
        printf("OE[%i]=0x%08x\n",i,gpios[i][GPIO_OE_REG/4]);
}