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//
// Copyright 2019 Ettus Research, a National Instruments Brand
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
#pragma once
#include <uhd/transport/adapter_id.hpp>
#include <uhd/types/device_addr.hpp>
#include <uhdlib/transport/io_service.hpp>
#include <uhdlib/transport/link_if.hpp>
#include <uhdlib/transport/links.hpp>
#include <uhdlib/usrp/common/io_service_args.hpp>
#include <memory>
namespace uhd { namespace usrp {
/*! Class to create and manage I/O services
*
* The I/O service manager connects links to I/O services, instantiating new I/O
* services as needed. It chooses the I/O service to connect based on options
* from the user passed through stream_args, as well as defaults provided by the
* caller.
*
* The I/O service manager supports two types of I/O services: inline I/O service
* and offload I/O service. Inline I/O services execute all I/O in the caller
* thread. Offload I/O services execute all I/O in an offload thread. The offload
* thread can be configured to block or poll. All control links use inline I/O
* services, only RX and TX data links currently use offload I/O services.
*
* If polling I/O services are requested, the I/O service manager instantiates
* the number of I/O services specified by the user through args. It chooses
* which I/O service to connect a set of links to by selecting the I/O service
* with the fewest number of connections.
*
* If blocking I/O services are requested, the I/O service manager instantiates
* one offload I/O service for each transport adapter used by a streamer. When
* there are multiple streamers, this manager creates a separate set of I/O
* services for each streamer.
*
* Offload I/O services have a number of restrictions that must be observed:
* - Offload I/O services currently do not support links that require frame
* buffers to be released in order.
* - Blocking I/O services should only be used for groups of RX or TX data
* transport in the same streamer. Since the I/O service blocks on each
* channel, if two streamers were to be configured to share the I/O service,
* one streamer would block the progress of the other. The I/O service
* manager ensures this restriction is observed by grouping I/O services
* and links appropriately.
* - Blocking I/O services do not currently support muxed links, since the I/O
* service is specialized to either RX or TX data and the procedure to configure
* a data transport requires both RX and TX clients. The I/O service manager
* throws an exception if requested to mux a link configured with a blocking
* I/O service.
*/
class io_service_mgr
{
public:
using sptr = std::shared_ptr<io_service_mgr>;
/*! Connects a pair of links to an I/O service
*
* Call this method to connect a pair of links to an I/O service. For muxed
* links, the I/O service manager keeps track of the number of muxed
* connections (the number of times this method has been called with the same
* links).
*
* The last two parameters are ignored for control links.
*
* \param recv_link The recv link to connect to an I/O service
* \param send_link The send link to connect to an I/O service
* \param link_type The type of transport in which the links will be used
* \param io_srv_args The default stream args for the device
* \param stream_args The user-provided stream args
* \param streamer_id A unique ID for the streamer that will use the links
* \return The I/O service to which the links are connected
*/
virtual transport::io_service::sptr connect_links(
transport::recv_link_if::sptr recv_link,
transport::send_link_if::sptr send_link,
const transport::link_type_t link_type,
const io_service_args_t& default_args = io_service_args_t(),
const uhd::device_addr_t& stream_args = uhd::device_addr_t(),
const std::string& streamer_id = "") = 0;
/*! Disconnects links from their I/O service
*
* \param recv_link The recv link to disconnect from an I/O service
* \param send_link The send link to disconnect from an I/O service
*/
virtual void disconnect_links(transport::recv_link_if::sptr recv_link,
transport::send_link_if::sptr send_link) = 0;
/*! Creates an instance of an I/O service manager
*
* \params Device args used to create the UHD session
* \return The I/O service manager instance
*/
static sptr make(const uhd::device_addr_t& args);
};
}} // namespace uhd::usrp
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