342 lines
9.5 KiB
C++
342 lines
9.5 KiB
C++
/*
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* \brief Block-session component
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* \author Christian Helmuth
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* \author Stefan Kalkowski
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* \date 2011-05-20
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*/
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/*
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* Copyright (C) 2011-2017 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__BLOCK__COMPONENT_H_
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#define _INCLUDE__BLOCK__COMPONENT_H_
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#include <base/log.h>
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#include <base/component.h>
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#include <base/allocator_avl.h>
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#include <base/heap.h>
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#include <root/component.h>
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#include <block/driver.h>
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namespace Block {
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using namespace Genode;
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class Session_component_base;
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class Session_component;
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class Root;
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};
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/**
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* We have a hen and egg situation that makes this base class necessary.
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* The Block::Session_rpc_object construction depends on a dataspace for
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* the packet stream. The dataspace on the other hand is constructed by
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* the driver, which is created on demand when creating a session.
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* When creating the driver, and dataspace outside the Session_component
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* constructor within _create_session of the root component, we would have
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* to destroy the driver and dataspace within the destructor body of
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* Session_component, which will lead to problems, because the packet stream
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* destructors will be called after the shared memory already vanished.
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*/
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class Block::Session_component_base
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{
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protected:
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Driver_factory &_driver_factory;
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Driver &_driver;
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Ram_dataspace_capability _rq_ds;
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Session_component_base(Driver_factory &factory, size_t tx_buf_size)
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: _driver_factory(factory),
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_driver(*factory.create()),
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_rq_ds(_driver.alloc_dma_buffer(tx_buf_size)) {}
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~Session_component_base()
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{
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_driver.free_dma_buffer(_rq_ds);
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_driver_factory.destroy(&_driver);
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}
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};
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class Block::Session_component : public Block::Session_component_base,
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public Block::Driver_session
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{
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private:
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addr_t _rq_phys;
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Signal_handler<Session_component> _sink_ack;
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Signal_handler<Session_component> _sink_submit;
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bool _req_queue_full = false;
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bool _ack_queue_full = false;
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Packet_descriptor _p_to_handle { };
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unsigned _p_in_fly;
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Info const _info { _driver.info() };
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bool const _writeable;
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/**
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* Acknowledge a packet already handled
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*/
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inline void _ack_packet(Packet_descriptor &packet)
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{
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if (!tx_sink()->ready_to_ack())
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error("not ready to ack!");
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tx_sink()->acknowledge_packet(packet);
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_p_in_fly--;
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}
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/**
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* Range check packet request
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*/
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inline bool _range_check(Packet_descriptor &p) {
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return p.block_number() + p.block_count() - 1
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< _info.block_count; }
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/**
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* Handle a single request
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*/
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void _handle_packet(Packet_descriptor packet)
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{
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_p_to_handle = packet;
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_p_to_handle.succeeded(false);
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/* ignore invalid packets */
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bool const valid = packet.size() && _range_check(_p_to_handle)
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&& tx_sink()->packet_valid(packet)
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&& aligned(packet.offset(), _info.align_log2);
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if (!valid) {
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_ack_packet(_p_to_handle);
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return;
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}
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try {
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switch (_p_to_handle.operation()) {
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case Block::Packet_descriptor::READ:
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if (_driver.dma_enabled())
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_driver.read_dma(packet.block_number(),
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packet.block_count(),
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_rq_phys + packet.offset(),
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_p_to_handle);
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else
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_driver.read(packet.block_number(),
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packet.block_count(),
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tx_sink()->packet_content(packet),
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_p_to_handle);
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break;
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case Block::Packet_descriptor::WRITE:
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if (!_writeable) {
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_ack_packet(_p_to_handle);
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break;
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}
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if (_driver.dma_enabled())
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_driver.write_dma(packet.block_number(),
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packet.block_count(),
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_rq_phys + packet.offset(),
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_p_to_handle);
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else
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_driver.write(packet.block_number(),
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packet.block_count(),
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tx_sink()->packet_content(packet),
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_p_to_handle);
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break;
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case Block::Packet_descriptor::SYNC:
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/* perform (blocking) sync */
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_driver.sync();
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_p_to_handle.succeeded(true);
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_ack_packet(_p_to_handle);
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_p_to_handle = Packet_descriptor();
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break;
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case Block::Packet_descriptor::TRIM:
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/* trim is a nop */
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_p_to_handle.succeeded(true);
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_ack_packet(_p_to_handle);
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_p_to_handle = Packet_descriptor();
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break;
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default:
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throw Driver::Io_error();
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}
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} catch (Driver::Request_congestion) {
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_req_queue_full = true;
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} catch (Driver::Io_error) {
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_ack_packet(_p_to_handle);
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} catch (Genode::Packet_descriptor::Invalid_packet) {
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_p_to_handle = Packet_descriptor();
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Genode::error("dropping invalid Block packet");
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}
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}
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/**
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* Called whenever a signal from the packet-stream interface triggered
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*/
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void _signal()
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{
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/*
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* as long as more packets are available, and we're able to ack
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* them, and the driver's request queue isn't full,
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* direct the packet request to the driver backend
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*/
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for (_ack_queue_full = (_p_in_fly >= tx_sink()->ack_slots_free());
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!_req_queue_full && !_ack_queue_full
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&& tx_sink()->packet_avail();
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_ack_queue_full = (++_p_in_fly >= tx_sink()->ack_slots_free()))
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_handle_packet(tx_sink()->get_packet());
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}
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public:
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/**
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* Constructor
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*
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* \param driver_factory factory to create and destroy driver objects
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* \param ep entrypoint handling this session component
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* \param buf_size size of packet-stream payload buffer
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*/
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Session_component(Driver_factory &driver_factory,
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Genode::Entrypoint &ep,
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Genode::Region_map &rm,
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size_t buf_size,
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bool writeable)
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: Session_component_base(driver_factory, buf_size),
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Driver_session(rm, _rq_ds, ep.rpc_ep()),
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_rq_phys(Dataspace_client(_rq_ds).phys_addr()),
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_sink_ack(ep, *this, &Session_component::_signal),
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_sink_submit(ep, *this, &Session_component::_signal),
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_req_queue_full(false),
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_p_in_fly(0),
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_writeable(writeable && _info.writeable)
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{
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_tx.sigh_ready_to_ack(_sink_ack);
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_tx.sigh_packet_avail(_sink_submit);
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_driver.session(this);
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}
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~Session_component() { _driver.session(nullptr); }
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/**
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* Acknowledges a packet processed by the driver to the client
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*
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* \param packet the packet to acknowledge
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* \param success indicated whether the processing was successful
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*
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* \throw Ack_congestion
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*/
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void ack_packet(Packet_descriptor &packet, bool success) override
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{
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packet.succeeded(success);
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_ack_packet(packet);
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if (!_req_queue_full && !_ack_queue_full)
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return;
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/*
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* when the driver's request queue was full,
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* handle last unprocessed packet taken out of submit queue
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*/
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if (_req_queue_full) {
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_req_queue_full = false;
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_handle_packet(_p_to_handle);
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}
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/* resume packet processing */
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_signal();
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}
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/*******************************
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** Block session interface **
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*******************************/
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Info info() const override { return _driver.info(); }
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};
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/**
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* Root component, handling new session requests
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*/
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class Block::Root : public Genode::Root_component<Block::Session_component,
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Single_client>
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{
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private:
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Driver_factory &_driver_factory;
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Genode::Entrypoint &_ep;
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Genode::Region_map &_rm;
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bool const _writeable;
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protected:
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/**
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* Always returns the singleton block-session component
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*/
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Session_component *_create_session(const char *args) override
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{
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size_t ram_quota =
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Arg_string::find_arg(args, "ram_quota" ).ulong_value(0);
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size_t tx_buf_size =
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Arg_string::find_arg(args, "tx_buf_size").ulong_value(0);
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/* delete ram quota by the memory needed for the session */
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size_t session_size = max((size_t)4096,
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sizeof(Session_component)
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+ sizeof(Allocator_avl));
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if (ram_quota < session_size)
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throw Insufficient_ram_quota();
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/*
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* Check if donated ram quota suffices for both
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* communication buffers. Also check both sizes separately
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* to handle a possible overflow of the sum of both sizes.
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*/
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if (tx_buf_size > ram_quota - session_size) {
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error("insufficient 'ram_quota', got ", ram_quota, ", need ",
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tx_buf_size + session_size);
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throw Insufficient_ram_quota();
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}
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bool writeable = _writeable
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? Arg_string::find_arg(args, "writeable").bool_value(true)
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: false;
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return new (md_alloc()) Session_component(_driver_factory,
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_ep, _rm, tx_buf_size,
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writeable);
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}
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public:
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/**
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* Constructor
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*
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* \param ep entrypoint handling this root component
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* \param md_alloc allocator to allocate session components
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* \param rm region map
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* \param driver_factory factory to create and destroy driver backend
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*/
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Root(Genode::Entrypoint &ep,
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Allocator &md_alloc,
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Genode::Region_map &rm,
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Driver_factory &driver_factory,
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bool writeable)
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:
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Root_component(ep, md_alloc),
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_driver_factory(driver_factory), _ep(ep), _rm(rm), _writeable(writeable)
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{ }
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};
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#endif /* _INCLUDE__BLOCK__COMPONENT_H_ */
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