SR_PRIV unsigned int fx2lafw_get_timeout(struct dev_context *devc) { size_t total_size; unsigned int timeout; total_size = fx2lafw_get_buffer_size(devc) * fx2lafw_get_number_of_transfers(devc); timeout = total_size / to_bytes_per_ms(devc->cur_samplerate); return timeout + timeout / 4; /* Leave a headroom of 25% percent. */ }
SR_PRIV unsigned int fx2lafw_get_number_of_transfers(struct dev_context *devc) { unsigned int n; /* Total buffer size should be able to hold about 500ms of data. */ n = (500 * to_bytes_per_ms(devc->cur_samplerate) / fx2lafw_get_buffer_size(devc)); if (n > NUM_SIMUL_TRANSFERS) return NUM_SIMUL_TRANSFERS; return n; }
static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data) { struct dev_context *devc; struct drv_context *drvc; struct sr_usb_dev_inst *usb; struct sr_trigger *trigger; struct libusb_transfer *transfer; unsigned int i, timeout, num_transfers; int ret; unsigned char *buf; size_t size; if (sdi->status != SR_ST_ACTIVE) return SR_ERR_DEV_CLOSED; drvc = di->priv; devc = sdi->priv; usb = sdi->conn; devc->cb_data = cb_data; devc->sent_samples = 0; devc->acq_aborted = FALSE; devc->empty_transfer_count = 0; if ((trigger = sr_session_trigger_get())) { devc->stl = soft_trigger_logic_new(sdi, trigger); devc->trigger_fired = FALSE; } else devc->trigger_fired = TRUE; timeout = fx2lafw_get_timeout(devc); num_transfers = fx2lafw_get_number_of_transfers(devc); size = fx2lafw_get_buffer_size(devc); devc->submitted_transfers = 0; devc->transfers = g_try_malloc0(sizeof(*devc->transfers) * num_transfers); if (!devc->transfers) { sr_err("USB transfers malloc failed."); return SR_ERR_MALLOC; } devc->num_transfers = num_transfers; for (i = 0; i < num_transfers; i++) { if (!(buf = g_try_malloc(size))) { sr_err("USB transfer buffer malloc failed."); return SR_ERR_MALLOC; } transfer = libusb_alloc_transfer(0); libusb_fill_bulk_transfer(transfer, usb->devhdl, 2 | LIBUSB_ENDPOINT_IN, buf, size, fx2lafw_receive_transfer, (void *)sdi, timeout); if ((ret = libusb_submit_transfer(transfer)) != 0) { sr_err("Failed to submit transfer: %s.", libusb_error_name(ret)); libusb_free_transfer(transfer); g_free(buf); fx2lafw_abort_acquisition(devc); return SR_ERR; } devc->transfers[i] = transfer; devc->submitted_transfers++; } devc->ctx = drvc->sr_ctx; usb_source_add(devc->ctx, timeout, receive_data, NULL); /* Send header packet to the session bus. */ std_session_send_df_header(cb_data, LOG_PREFIX); if ((ret = fx2lafw_command_start_acquisition(sdi)) != SR_OK) { fx2lafw_abort_acquisition(devc); return ret; } return SR_OK; }