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#include <stdio.h> | |
#include <stdint.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include <string.h> | |
#include <fcntl.h> | |
#include <sys/time.h> | |
#include <sys/mman.h> | |
#include <sys/types.h> | |
#include <sched.h> | |
#define BCM2708_PERI_BASE 0x20000000 | |
#define GPIO_BASE (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */ | |
#define PAGE_SIZE (4*1024) | |
#define BLOCK_SIZE (4*1024) | |
// I/O access | |
volatile unsigned *gpio; | |
// Time for easy calculations | |
static unsigned long long epoch; | |
#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3)) | |
// these define only works for the first 32 pins! | |
#define GPIO_LEV *(gpio+13) // read pin level: 0=LOW | 1=HIGH | |
#define TEST_INP 18 | |
#define TEST_INP_LEV (GPIO_LEV & (1 << TEST_INP)) | |
#define PASS_COUNT 3 | |
#define FAST_COUNT 10000000 | |
int piHiPri(); | |
unsigned int millis(); | |
int setup_io(); | |
int main(void) | |
{ | |
unsigned int i = PASS_COUNT; | |
uint32_t start, diff, count, sum; | |
printf ("Raspberry Pi native-C GPIO input speed test program\n") ; | |
piHiPri(); | |
if (setup_io() < 0) return -1; | |
INP_GPIO(TEST_INP); | |
for (; i--;) | |
{ | |
printf(" Pass: %d: ", i); | |
fflush(stdout); | |
count = FAST_COUNT; | |
start = millis(); | |
for (; count != 0;--count) { | |
if(TEST_INP_LEV) { /* do nothing */} | |
} | |
diff = millis() - start; | |
printf(" %8dmS\n", diff); | |
sum += diff; | |
} | |
uint32_t avg = sum / PASS_COUNT; // <- this calculates wrong w/o fix | |
//printf("%d\n",sum); // fixes O3 to O0-O2 levels (from ~350 million to ~12k) | |
//printf("%d / %d\n",sum, PASS_COUNT); // fixes all cases | |
printf(" Average: %8dmS", avg); // w/o fix this prints ~12k on O0-O2 and ~350 million on O3 | |
printf(": %6d/msec\n", (int)(double)FAST_COUNT / avg); | |
} | |
/* | |
* piHiPri: | |
* Attempt to set a high priority schedulling for the running program | |
* This function comes from wiringPi (slightly modified) ! | |
********************************************************************************* | |
*/ | |
int piHiPri() | |
{ | |
struct sched_param sched; | |
memset(&sched, 0, sizeof(sched)); | |
sched.sched_priority = sched_get_priority_max(SCHED_RR); | |
return sched_setscheduler(0, SCHED_RR, &sched); | |
} | |
/* | |
* millis: | |
* Return a number of milliseconds as an unsigned int. | |
********************************************************************************* | |
*/ | |
unsigned int millis (void) | |
{ | |
struct timeval tv ; | |
unsigned long long t1 ; | |
gettimeofday (&tv, NULL) ; | |
t1 = (tv.tv_sec * 1000000 + tv.tv_usec) / 1000 ; | |
return (uint32_t)(t1 - epoch) ; | |
} | |
// | |
// Set up a memory regions to access GPIO | |
// | |
int setup_io() | |
{ | |
int mem_fd; | |
char *gpio_mem, *gpio_map; | |
struct timeval tv; | |
/* open /dev/mem */ | |
if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) { | |
printf("can't open /dev/mem \n"); | |
return -1; | |
} | |
/* mmap GPIO */ | |
// Allocate MAP block | |
if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL) { | |
printf("allocation error \n"); | |
return -1; | |
} | |
// Make sure pointer is on 4K boundary | |
if ((unsigned long)gpio_mem % PAGE_SIZE) | |
gpio_mem += PAGE_SIZE - ((unsigned long)gpio_mem % PAGE_SIZE); | |
// Now map it | |
gpio_map = (unsigned char *)mmap( | |
(caddr_t)gpio_mem, | |
BLOCK_SIZE, | |
PROT_READ|PROT_WRITE, | |
MAP_SHARED|MAP_FIXED, | |
mem_fd, | |
GPIO_BASE | |
); | |
if ((long)gpio_map < 0) { | |
printf("mmap error %d\n", (int)gpio_map); | |
return -1; | |
} | |
// Always use volatile pointer! | |
gpio = (volatile unsigned *)gpio_map; | |
// Initialise our epoch for millis() | |
gettimeofday (&tv, NULL); | |
epoch = (tv.tv_sec * 1000000 + tv.tv_usec) / 1000; | |
return 0; | |
} // setup_io |
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