/* Precondition: A transfer is available. */
static int submit_transfer(struct bladerf_stream *stream, void *buffer)
{
int status;
struct bladerf_lusb *lusb = lusb_backend(stream->dev);
struct lusb_stream_data *stream_data = stream->backend_data;
struct libusb_transfer *transfer;
size_t bytes_per_buffer;
const unsigned char ep =
stream->module == BLADERF_MODULE_TX ? SAMPLE_EP_OUT : SAMPLE_EP_IN;
assert(stream_data->transfer_status[stream_data->i] == TRANSFER_AVAIL);
transfer = stream_data->transfers[stream_data->i];
switch (stream->format) {
case BLADERF_FORMAT_SC16_Q11:
bytes_per_buffer = c16_samples_to_bytes(stream->samples_per_buffer);
break;
default:
assert(!"Unexpected format");
return BLADERF_ERR_INVAL;
}
assert(bytes_per_buffer <= INT_MAX);
libusb_fill_bulk_transfer(transfer,
lusb->handle,
ep,
buffer,
(int)bytes_per_buffer,
lusb_stream_cb,
stream,
stream->dev->transfer_timeout[stream->module]);
status = libusb_submit_transfer(transfer);
if (status == 0) {
stream_data->transfer_status[stream_data->i] = TRANSFER_IN_FLIGHT;
stream_data->i = (stream_data->i + 1) % stream_data->num_transfers;
assert(stream_data->num_avail_transfers != 0);
stream_data->num_avail_transfers--;
} else {
log_error("Failed to submit transfer in %s: %s\n",
__FUNCTION__, libusb_error_name(status));
}
return error_conv(status);
}
/* Precondition: A transfer is available. */
static int submit_transfer(struct bladerf_stream *stream, void *buffer)
{
int status;
struct bladerf_lusb *lusb = lusb_backend(stream->dev);
struct lusb_stream_data *stream_data = stream->backend_data;
struct libusb_transfer *transfer;
const size_t bytes_per_buffer = async_stream_buf_bytes(stream);
size_t prev_idx;
const unsigned char ep =
stream->module == BLADERF_MODULE_TX ? SAMPLE_EP_OUT : SAMPLE_EP_IN;
transfer = get_next_available_transfer(stream_data);
assert(transfer != NULL);
assert(bytes_per_buffer <= INT_MAX);
libusb_fill_bulk_transfer(transfer,
lusb->handle,
ep,
buffer,
(int)bytes_per_buffer,
lusb_stream_cb,
stream,
stream->dev->transfer_timeout[stream->module]);
prev_idx = stream_data->i;
stream_data->transfer_status[stream_data->i] = TRANSFER_IN_FLIGHT;
stream_data->i = (stream_data->i + 1) % stream_data->num_transfers;
assert(stream_data->num_avail != 0);
stream_data->num_avail--;
/* FIXME We have an inherent issue here with lock ordering between
* stream->lock and libusb's underlying event lock, so we
* have to drop the stream->lock as a workaround.
*
* This implies that a callback can potentially execute,
* including a callback for this transfer. Therefore, the transfer
* has been setup and its metadata logged.
*
* Ultimately, we need to review our async scheme and associated
* lock schemes.
*/
MUTEX_UNLOCK(&stream->lock);
status = libusb_submit_transfer(transfer);
MUTEX_LOCK(&stream->lock);
if (status != 0) {
log_error("Failed to submit transfer in %s: %s\n",
__FUNCTION__, libusb_error_name(status));
/* We need to undo the metadata we updated prior to dropping
* the lock and attempting to submit the transfer */
assert(stream_data->transfer_status[prev_idx] == TRANSFER_IN_FLIGHT);
stream_data->transfer_status[prev_idx] = TRANSFER_AVAIL;
stream_data->num_avail++;
if (stream_data->i == 0) {
stream_data->i = stream_data->num_transfers - 1;
} else {
stream_data->i--;
}
}
return error_conv(status);
}
