genode/repos/os/include/nic/component.h

/*
 * \brief  Glue between device-specific NIC driver code and Genode
 * \author Norman Feske
 * \date   2011-05-21
 */

/*
 * Copyright (C) 2011-2013 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU General Public License version 2.
 */

#ifndef _INCLUDE__NIC__COMPONENT_H_
#define _INCLUDE__NIC__COMPONENT_H_

#include <base/env.h>
#include <nic_session/rpc_object.h>
#include <base/allocator_avl.h>
#include <util/arg_string.h>
#include <base/rpc_server.h>
#include <root/component.h>
#include <nic/driver.h>

enum { VERBOSE_RX = false };

namespace Nic {

	class Session_component;

	/**
	 * Shortcut for single-client NIC root component
	 */
	typedef Genode::Root_component<Session_component, Genode::Single_client>
	        Root_component;

	class Root;
}


class Nic::Session_component : public Genode::Allocator_avl,
                               public Session_rpc_object, public Rx_buffer_alloc,
                               public Driver_notification
{
	private:

		Driver_factory &_driver_factory;
		Driver         &_driver;

		Genode::Signal_context_capability _link_state_sigh;

		/* rx packet descriptor */
		Genode::Packet_descriptor _curr_rx_packet;

		enum { TX_STACK_SIZE = 8*1024 };
		class Tx_thread : public Genode::Thread<TX_STACK_SIZE>
		{
			private:

				Tx::Sink *_tx_sink;
				Driver   &_driver;

			public:

				Tx_thread(Tx::Sink *tx_sink, Driver &driver)
				:
					Genode::Thread<TX_STACK_SIZE>("tx"),
					_tx_sink(tx_sink), _driver(driver)
				{
					start();
				}

				void entry()
				{
					using namespace Genode;

					while (true) {

						/* block for packet from client */
						Packet_descriptor packet = _tx_sink->get_packet();
						if (!packet.valid()) {
							PWRN("received invalid packet");
							continue;
						}

						_driver.tx(_tx_sink->packet_content(packet),
						           packet.size());

						/* acknowledge packet to the client */
						if (!_tx_sink->ready_to_ack())
							PDBG("need to wait until ready-for-ack");
						_tx_sink->acknowledge_packet(packet);
					}
				}
		} _tx_thread;

		void dump()
		{
			using namespace Genode;

			if (!VERBOSE_RX) return;

			char  *buf  = (char *)_rx.source()->packet_content(_curr_rx_packet);
			size_t size = _curr_rx_packet.size();

			printf("rx packet:");
			for (unsigned i = 0; i < size; i++)
				printf("%02x,", buf[i]);
			printf("\n");
		}

	public:

		/**
		 * Constructor
		 *
		 * \param tx_buf_size        buffer size for tx channel
		 * \param rx_buf_size        buffer size for rx channel
		 * \param rx_block_alloc     rx block allocator
		 * \param ep                 entry point used for packet stream
		 */
		Session_component(Genode::size_t          tx_buf_size,
		                  Genode::size_t          rx_buf_size,
		                  Nic::Driver_factory    &driver_factory,
		                  Genode::Rpc_entrypoint &ep)
		:
			Genode::Allocator_avl(Genode::env()->heap()),
			Session_rpc_object(Genode::env()->ram_session()->alloc(tx_buf_size),
			                   Genode::env()->ram_session()->alloc(rx_buf_size),
			                   static_cast<Genode::Range_allocator *>(this), ep),
			_driver_factory(driver_factory),
			_driver(*driver_factory.create(*this, *this)),
			_tx_thread(_tx.sink(), _driver)
		{ }

		/**
		 * Destructor
		 */
		~Session_component()
		{
			_driver_factory.destroy(&_driver);
		}

		/***********************************
		 ** Driver-notification interface **
		 ***********************************/

		void link_state_changed() override
		{
			if (_link_state_sigh.valid())
				Genode::Signal_transmitter(_link_state_sigh).submit();
		}

		/*******************************
		 ** Rx_buffer_alloc interface **
		 *******************************/

		void *alloc(Genode::size_t size) override
		{
			/* assign rx packet descriptor */
			_curr_rx_packet = _rx.source()->alloc_packet(size);

			return _rx.source()->packet_content(_curr_rx_packet);
		}

		void submit() override
		{
			/* check for acknowledgements from the client */
			while (_rx.source()->ack_avail()) {
				Genode::Packet_descriptor packet = _rx.source()->get_acked_packet();

				/* free packet buffer */
				_rx.source()->release_packet(packet);
			}

			dump();

			_rx.source()->submit_packet(_curr_rx_packet);

			/* invalidate rx packet descriptor */
			_curr_rx_packet = Packet_descriptor();
		}


		/****************************
		 ** Nic::Session interface **
		 ****************************/

		Mac_address mac_address() { return _driver.mac_address(); }
		bool        link_state()  { return _driver.link_state(); }
		Tx::Sink*   tx_sink()     { return _tx.sink();   }
		Rx::Source* rx_source()   { return _rx.source(); }

		void link_state_sigh(Genode::Signal_context_capability sigh) override
		{
			_link_state_sigh = sigh;
		}
};


/*
 * Root component, handling new session requests.
 */
class Nic::Root : public Root_component
{
	private:

		Driver_factory         &_driver_factory;
		Genode::Rpc_entrypoint &_ep;

	protected:

		/*
		 * Always returns the singleton nic-session component.
		 */
		Session_component *_create_session(const char *args)
		{
			using namespace Genode;

			Genode::size_t ram_quota =
				Arg_string::find_arg(args, "ram_quota"  ).ulong_value(0);
			Genode::size_t tx_buf_size =
				Arg_string::find_arg(args, "tx_buf_size").ulong_value(0);
			Genode::size_t rx_buf_size =
				Arg_string::find_arg(args, "rx_buf_size").ulong_value(0);

			/* delete ram quota by the memory needed for the session */
			Genode::size_t session_size = max((Genode::size_t)4096, sizeof(Session_component)
			                                  + sizeof(Allocator_avl));
			if (ram_quota < session_size)
				throw Root::Quota_exceeded();

			/*
			 * Check if donated ram quota suffices for both
			 * communication buffers. Also check both sizes separately
			 * to handle a possible overflow of the sum of both sizes.
			 */
			if (tx_buf_size                  > ram_quota - session_size
				|| rx_buf_size               > ram_quota - session_size
				|| tx_buf_size + rx_buf_size > ram_quota - session_size) {
				PERR("insufficient 'ram_quota', got %zd, need %zd",
				     ram_quota, tx_buf_size + rx_buf_size + session_size);
				throw Root::Quota_exceeded();
			}

			return new (md_alloc()) Session_component(tx_buf_size,
			                                          rx_buf_size,
			                                          _driver_factory,
			                                          _ep);
		}

	public:

		Root(Genode::Rpc_entrypoint *session_ep,
		     Genode::Allocator      *md_alloc,
		     Nic::Driver_factory    &driver_factory)
		:
			Root_component(session_ep, md_alloc),
			_driver_factory(driver_factory),
			_ep(*session_ep)
		{ }
};

#endif /* _INCLUDE__NIC__COMPONENT_H_ */