#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <rtai.h>
#include <rtai_sched.h>
#include <rtai_shm.h>
#include <rtai_nam2num.h>

MODULE_DESCRIPTION("Simple SHM demo");
MODULE_AUTHOR("Y. Kobayashi");
MODULE_LICENSE("GPL");

#define STACK_SIZE    4000

#include "adc.h"
#include "period.h"

static RT_TASK thread;

static float *data;
static struct my_msg_struct * msg;
static RTIME tick_period;

static void fun(long t_dummy)
{
	RTIME s_time;
	float t, t0;
	int count, count_record = 0, flag = 0;

	while (1) {

		if (msg->command == START_TASK) {
			msg->command = STOP_TASK;
			flag = 1;

			count = 0;
			count_record = 0;
			s_time = rt_get_time();
			t0 = 0;
			rt_task_make_periodic(&thread, s_time, tick_period);
		}

		if(flag == 1){
			  
			t = count2nano(rt_get_time() - s_time)*1.0e-9;

			count++;
			if(count == 2){
				da_conv(1.0, 0);
				count = 0;
			}else{
				da_conv(0, 0);
			}

			if(count_record < BUF_LEN * RECORDING_SAMPLES){
				data[count_record++] = t; // 現在時刻
				data[count_record++] = t - t0; // 前回からの差分
				t0 = t;
			}else{
				flag = 0;
				rt_task_make_periodic(&thread, rt_get_time(), tick_period*PERIOD_COUNT);
			}

		}

		rt_task_wait_period();

	}
}

int
init_module(void)
{
  //	RTIME tick_period;
	RTIME now;

	if((data = (float *)rtai_kmalloc(nam2num("data"), BUF_LEN * RECORDING_SAMPLES * sizeof(float))) == NULL){
		return -ENOMEM;
	}

	if((msg = (struct my_msg_struct *)rtai_kmalloc(nam2num("msg"), sizeof(struct my_msg_struct))) == NULL){
		return -ENOMEM;
	}
	msg->command = STOP_TASK;

	rt_task_init(&thread, fun, 0, STACK_SIZE, 0, 1, 0); // 後ろから 2 番地目の 1 = use_fpu を有効にしておかないと、data[] の一部に nan が入る
	tick_period = start_rt_timer(nano2count(SAMPLING_PERIOD));
	rt_linux_use_fpu(1);
	now = rt_get_time();
	rt_task_make_periodic(&thread, now + tick_period, tick_period*PERIOD_COUNT);

	init_dac();

	return 0;
}

void
cleanup_module(void)
{
	stop_rt_timer();
	rt_busy_sleep(10000000);
	rt_task_delete(&thread);
	rtai_kfree(nam2num("data"));
	rtai_kfree(nam2num("msg"));

	cleanup_dac();
}