/* This function calibrates the datarate (i.e. determines the maximal
* usable data rate) and sets the global variable ft_qic_std to qic_std
*
*/
int ftape_calibrate_data_rate(unsigned int qic_std)
{
int rate = ft_fdc_rate_limit;
int result;
TRACE_FUN(ft_t_flow);
ft_qic_std = qic_std;
if (ft_qic_std == -1) {
TRACE_ABORT(-EIO, ft_t_err,
"Unable to determine data rate if QIC standard is unknown");
}
/* Select highest rate supported by both fdc and drive.
* Start with highest rate supported by the fdc.
*/
while (fdc_set_data_rate(rate) < 0 && rate > 250) {
rate /= 2;
}
TRACE(ft_t_info,
"Highest FDC supported data rate: %d Kbps", rate);
ft_fdc_max_rate = rate;
do {
result = ftape_set_data_rate(rate, ft_qic_std);
} while (result == -EINVAL && (rate /= 2) > 250);
if (result < 0) {
TRACE_ABORT(-EIO, ft_t_err, "set datarate failed");
}
ft_data_rate = rate;
TRACE_EXIT 0;
}
int ftape_set_data_rate(unsigned int new_rate /* Kbps */, unsigned int qic_std)
{
int status;
int result = 0;
unsigned int data_rate = new_rate;
static int supported;
int rate_changed = 0;
qic_model dummy_model;
unsigned int dummy_qic_std, dummy_tape_len;
TRACE_FUN(ft_t_any);
if (ft_drive_max_rate == 0) { /* first time */
supported = ftape_set_rate_test(&ft_drive_max_rate);
}
if (supported) {
ftape_command(QIC_SELECT_RATE);
result = ftape_parameter_wait(qic_rate_code(new_rate),
1 * FT_SECOND, &status);
if (result >= 0 && !(status & QIC_STATUS_ERROR)) {
rate_changed = 1;
}
}
TRACE_CATCH(result = ftape_report_configuration(&dummy_model,
&data_rate,
&dummy_qic_std,
&dummy_tape_len),);
if (data_rate != new_rate) {
if (!supported) {
TRACE(ft_t_warn, "Rate change not supported!");
} else if (rate_changed) {
TRACE(ft_t_warn, "Requested: %d, got %d",
new_rate, data_rate);
} else {
TRACE(ft_t_warn, "Rate change failed!");
}
result = -EINVAL;
}
/*
* Set data rate and write precompensation as specified:
*
* | QIC-40/80 | QIC-3010/3020
* rate | precomp | precomp
* ----------+-------------+--------------
* 250 Kbps. | 250 ns. | 0 ns.
* 500 Kbps. | 125 ns. | 0 ns.
* 1 Mbps. | 42 ns. | 0 ns.
* 2 Mbps | N/A | 0 ns.
*/
if ((qic_std == QIC_TAPE_QIC40 && data_rate > 500) ||
(qic_std == QIC_TAPE_QIC80 && data_rate > 1000)) {
TRACE_ABORT(-EINVAL,
ft_t_warn, "Datarate too high for QIC-mode");
}
TRACE_CATCH(fdc_set_data_rate(data_rate),_res = -EINVAL);
ft_data_rate = data_rate;
if (qic_std == QIC_TAPE_QIC40 || qic_std == QIC_TAPE_QIC80) {
switch (data_rate) {
case 250:
fdc_set_write_precomp(250);
break;
default:
case 500:
fdc_set_write_precomp(125);
break;
case 1000:
fdc_set_write_precomp(42);
break;
}
} else {
fdc_set_write_precomp(0);
}
TRACE_EXIT result;
}
