Pioneer SR-link control - Raspberry PI

srlink.c

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

// SR Control pulses (IR pulses without modulation)
#define HDR_MARK    9000
#define HDR_PAUSE   4500
#define BIT_MARK    560
#define ONE_PAUSE   1600
#define ZERO_PAUSE  560

// SR Control codes:
#define SR_VOLUME_UP    0xA55A50AF
#define SR_VOLUME_DOWN  0xA55AD02F
#define SR_TOGGLE_PWR   0xA55A38C7
#define SR_INPUT_HDMI   0xA55A7A85

static volatile uint32_t *gpio;

void sendCode(unsigned long data, int nbits);
void sendPulse(long microsecs);

int main(int argc, char **argv)
{
	int fd, i;

	// Open memory handle
	if ((fd = open ("/dev/mem", O_RDWR | O_SYNC) ) < 0) {
		printf("Unable to open /dev/mem: %s\n", strerror(errno));
		return -1;
	}

	// map memory to gpio at offset 0x20200000 (gpio start..)
	gpio = (uint32_t *)mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0x20200000);

	if ((int32_t)gpio < 0){
		printf("Mmap failed: %s\n", strerror(errno));
		return -1;
	}

	//set gpio17 as an output
	*(gpio + 1) = (*(gpio + 1) & ~(7 << 21)) | (1 << 21);

	//set gpio17 high:
	*(gpio + 7) = 1 << 17;
	sleep(1);

	for (i = 0; i < 5; i++) {
		sendCode(SR_VOLUME_UP, 32);
		sleep(1);
		sendCode(SR_VOLUME_DOWN, 32);
		sleep(1);
	}
}

void sendPulse(long microsecs)
{
	// Take GPIO 17 low, wait, then high. (one pulse..)
	*(gpio + 10) = 1 << 17;
	usleep(microsecs);
	*(gpio + 7) = 1 << 17;
}

void sendCode(unsigned long data, int nbits)
{
	int i;
	
	sendPulse(HDR_MARK);
	usleep(HDR_PAUSE);
	
	for (i = 0; i < nbits; i++)
	{
		sendPulse(BIT_MARK);
		
		if (data & 0x80000000)
			usleep(ONE_PAUSE);
		else
			usleep(ZERO_PAUSE);
		
		data <<= 1;
	}
}

SR link appears to have a common header: A5 5A
then a one byte command and a one byte checksum. Command and checksum add to hex FF (255)
I wonder if those commands are publshed by Pioneer?