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141 lines
3.2 KiB
C++
141 lines
3.2 KiB
C++
/*
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* \brief Packet stream helper
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* \author Sebastian Sumpf
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* \date 2014-12-08
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*/
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/*
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* Copyright (C) 2014-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__USB__PACKET_HANDLER_
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#define _INCLUDE__USB__PACKET_HANDLER_
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#include <base/lock.h>
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#include <usb_session/connection.h>
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namespace Usb { class Packet_handler; }
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class Usb::Packet_handler
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{
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private:
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Usb::Connection &_connection;
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Genode::Entrypoint &_ep;
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Io_signal_handler<Packet_handler> _rpc_ack_avail {
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_ep, *this, &Packet_handler::_packet_handler };
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Io_signal_handler<Packet_handler> _rpc_ready_submit {
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_ep, *this, &Packet_handler::_ready_handler };
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bool _ready_submit = true;
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bool _in_completion = false;
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void _packet_handler()
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{
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if (!_ready_submit)
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return;
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while (packet_avail()) {
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Packet_descriptor p = _connection.source()->get_acked_packet();
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if (p.completion) {
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_in_completion = true;
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p.completion->complete(p);
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_in_completion = false;
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} else
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release(p);
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}
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}
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void _ready_handler()
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{
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_ready_submit = true;
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};
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public:
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Packet_handler(Connection &connection, Genode::Entrypoint &ep)
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: _connection(connection), _ep(ep)
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{
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/* connect 'ack_avail' to our rpc member */
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_connection.tx_channel()->sigh_ack_avail(_rpc_ack_avail);
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_connection.tx_channel()->sigh_ready_to_submit(_rpc_ready_submit);
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}
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/***************************
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** Packet stream wrapper **
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***************************/
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bool packet_avail() const
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{
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return _connection.source()->ack_avail();
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}
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void wait_for_packet()
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{
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if (packet_avail()) { _packet_handler(); }
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else { _ep.wait_and_dispatch_one_io_signal(); }
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}
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Packet_descriptor alloc(size_t size)
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{
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/* is size larger than packet stream */
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if (size > _connection.source()->bulk_buffer_size()) {
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Genode::error("packet allocation of (", size, " bytes) too large, "
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"buffer has ", _connection.source()->bulk_buffer_size(),
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" bytes");
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throw Usb::Session::Tx::Source::Packet_alloc_failed();
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}
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while (true) {
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try {
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Packet_descriptor p = _connection.source()->alloc_packet(size);
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return p;
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} catch (Usb::Session::Tx::Source::Packet_alloc_failed) {
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/* block until some packets are freed */
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wait_for_packet();
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}
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}
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}
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void submit(Packet_descriptor &p)
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{
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/* check if submit queue is full */
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if (!_connection.source()->ready_to_submit()) {
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_ready_submit = false;
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/* wait for ready_to_submit signal */
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while (!_ready_submit)
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_ep.wait_and_dispatch_one_io_signal();
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}
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_connection.source()->submit_packet(p);
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/*
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* If an acknowledgement available signal occurred in the meantime,
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* retrieve packets, but avoid recursion if 'submit()' was called
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* from the completion handler.
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*/
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if (packet_avail() && !_in_completion)
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_packet_handler();
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}
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void *content(Packet_descriptor &p)
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{
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return _connection.source()->packet_content(p);
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}
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void release(Packet_descriptor &p)
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{
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_connection.source()->release_packet(p);
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}
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};
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#endif /* _INCLUDE__USB__PACKET_HANDLER_ */
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