Created
August 15, 2016 21:58
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Memtest
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/* | |
* This test application is to read/write data directly from/to the device | |
* from userspace. | |
* | |
*/ | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include <sys/mman.h> | |
#include <fcntl.h> | |
#define IN 0 | |
#define OUT 1 | |
void usage(void) | |
{ | |
printf("*argv[0] -g <GPIO_ADDRESS> -i|-o <VALUE>\n"); | |
printf(" -g <GPIO_ADDR> GPIO physical address\n"); | |
printf(" -i Input from GPIO\n"); | |
printf(" -o <VALUE> Output to GPIO\n"); | |
return; | |
} | |
int main(int argc, char *argv[]) | |
{ | |
int c; | |
int fd; | |
int direction=IN; | |
unsigned gpio_addr = 0; | |
int value = 0; | |
unsigned page_addr, page_offset; | |
void *ptr; | |
unsigned page_size=sysconf(_SC_PAGESIZE); | |
printf("GPIO access through /dev/mem.\n", page_size); | |
/* Parse command line arguements */ | |
while((c = getopt(argc, argv, "g:io:h")) != -1) { | |
switch(c) { | |
case 'g': | |
gpio_addr=strtoul(optarg,NULL, 0); | |
break; | |
case 'i': | |
direction=IN; | |
break; | |
case 'o': | |
direction=OUT; | |
value=atoi(optarg); | |
break; | |
case 'h': | |
usage(); | |
return 0; | |
default: | |
printf("invalid option: %c\n", (char)c); | |
usage(); | |
return -1; | |
} | |
} | |
if (gpio_addr == 0) { | |
printf("GPIO physical address is required.\n"); | |
usage(); | |
return -1; | |
} | |
/* Open /dev/mem file */ | |
fd = open ("/dev/mem", O_RDWR); | |
if (fd < 1) { | |
perror(argv[0]); | |
return -1; | |
} | |
/* mmap the device into memory */ | |
page_addr = (gpio_addr & (~(page_size-1))); | |
page_offset = gpio_addr - page_addr; | |
ptr = mmap(NULL, page_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, page_addr); | |
if (direction == IN) { | |
/* Read value from the device register */ | |
value = *((unsigned *)(ptr + page_offset)); | |
printf("gpio dev-mem test: input: %08x\n",value); | |
} else { | |
/* Write value to the device register */ | |
*((unsigned *)(ptr + page_offset)) = value; | |
} | |
munmap(ptr, page_size); | |
return 0; | |
} |
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