952 /*****************************************************************************/

   953 

   954 /**

   955    Measures the time, a frame is on the bus.

   956 */

   957 

   958 void ec_master_measure_bus_time(ec_master_t *master)

   959 {

   960     ec_datagram_t datagram;

   961     cycles_t t_start, t_end, t_timeout;

   962     uint32_t times[100], sum, min, max, i;

   963 

   964     ec_datagram_init(&datagram);

   965 

   966     if (ec_datagram_brd(&datagram, 0x130, 2)) {

   967         EC_ERR("Failed to allocate datagram for bus time measuring.\n");

   968         ec_datagram_clear(&datagram);

   969         return;

   970     }

   971 

   972     t_timeout = (cycles_t) EC_IO_TIMEOUT * (cpu_khz / 1000);

   973 

   974     sum = 0;

   975     min = 0xFFFFFFFF;

   976     max = 0;

   977 

   978     for (i = 0; i < 100; i++) {

   979         ec_master_queue_datagram(master, &datagram);

   980         ecrt_master_send(master);

   981         t_start = get_cycles();

   982 

   983         while (1) { // active waiting

   984             ec_device_call_isr(master->device);

   985             t_end = get_cycles(); // take current time

   986 

   987             if (datagram.state == EC_DATAGRAM_RECEIVED) {

   988                 break;

   989             }

   990             else if (datagram.state == EC_DATAGRAM_ERROR) {

   991                 EC_WARN("Failed to measure bus time.\n");

   992                 goto error;

   993             }

   994             else if (t_end - t_start >= t_timeout) {

   995                 EC_WARN("Timeout while measuring bus time.\n");

   996                 goto error;

   997             }

   998         }

   999 

  1000         times[i] = (unsigned int) (t_end - t_start) * 1000 / cpu_khz;

  1001         sum += times[i];

  1002         if (times[i] > max) max = times[i];

  1003         if (times[i] < min) min = times[i];

  1004     }

  1005 

  1006     EC_INFO("Bus time is (min/avg/max) %u/%u.%u/%u us.\n",

  1007             min, sum / 100, sum % 100, max);

  1008 

  1009   error:

  1010     // Dequeue and free datagram

  1011     list_del(&datagram.queue);

  1012     ec_datagram_clear(&datagram);

  1013 }

  1014