/*
 * \brief  Pistachio pager support for Genode
 * \author Christian Helmuth
 * \date   2006-06-14
 */

/*
 * Copyright (C) 2006-2012 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__BASE__IPC_PAGER_H_
#define _INCLUDE__BASE__IPC_PAGER_H_

/* Genode includes */
#include <base/native_types.h>
#include <base/ipc.h>
#include <base/stdint.h>
#include <util/touch.h>
#include <pistachio/kip.h>

/* Pistachio includes */
namespace Pistachio {
#include <l4/types.h>
}

namespace Genode {

	class Mapping
	{
		private:

			union {
				Pistachio::L4_MapItem_t   _map_item;
				Pistachio::L4_GrantItem_t _grant_item;
			};

			/*
			 * On Pistachio, the write-combining attribute is not part of a mapping
			 * but it can be applied to a flexpage via the memory-control system
			 * call. Therefore, we need to keep the flag in an extra member variable.
			 */
			bool _write_combined;  /* enable write-combined access to I/O memory */

		public:

			/**
			 * Constructor
			 */
			Mapping(addr_t dst_addr, addr_t src_addr,
			        bool write_combined, bool io_mem,
			        unsigned l2size = Pistachio::get_page_size_log2(),
			        bool rw = true, bool grant = false);

			/**
			 * Construct invalid mapping
			 */
			Mapping();

			addr_t _dst_addr() const { return Pistachio::L4_SndBase(_map_item); }

			Pistachio::L4_Fpage_t fpage() const {
				return Pistachio::L4_MapItemSndFpage(_map_item); }

			Pistachio::L4_MapItem_t map_item() const { return _map_item; };

			/**
			 * Prepare map operation
			 *
			 * On Pistachio, we need to map a page locally to be able to map it
			 * to another address space.
			 */
			void prepare_map_operation()
			{
				using namespace Pistachio;
				unsigned char volatile *core_local_addr =
					(unsigned char volatile *)L4_Address(_map_item.X.snd_fpage);

				if (L4_Rights(_map_item.X.snd_fpage) & L4_Writable)
					touch_read_write(core_local_addr);
				else
					touch_read(core_local_addr);
			}
	};


	/**
	 * Special paging server class
	 */
	class Ipc_pager : public Native_capability
	{
		private:

			Pistachio::L4_ThreadId_t _last;       /* origin of last fault message   */
			Pistachio::L4_Word_t     _flags;      /* page-fault attributes          */
			addr_t                   _pf_addr;    /* page-fault address             */
			addr_t                   _pf_ip;      /* instruction pointer of faulter */
			Pistachio::L4_MapItem_t  _map_item;   /* page-fault answer              */

		protected:

			/**
			 * Wait for short-message (register) IPC -- pagefault
			 */
			void _wait();

			/**
			 * Send short flex page and
			 * wait for next short-message (register) IPC -- pagefault
			 */
			void _reply_and_wait();

		public:

			/**
			 * Constructor
			 */
			Ipc_pager();

			/**
			 * Wait for a new fault received as short message IPC
			 */
			void wait_for_fault();

			/**
			 * Reply current fault and wait for a new one
			 *
			 * Send short flex page and wait for next short-message (register)
			 * IPC -- pagefault
			 */
			void reply_and_wait_for_fault();

			/**
			 * Request instruction pointer of current fault
			 */
			addr_t fault_ip() { return _pf_ip; }

			/**
			 * Request fault address of current page fault
			 */
			addr_t fault_addr() { return _pf_addr & ~3; }

			/**
			 * Set parameters for next reply
			 */
			void set_reply_mapping(Mapping m) { _map_item = m.map_item(); }

			/**
			 * Set destination for next reply
			 */
			void set_reply_dst(Native_capability pager_object) {
				_last.raw = pager_object.local_name(); }

			/**
			 * Answer call without sending a flex-page mapping
			 *
			 * This function is used to acknowledge local calls from one of
			 * core's region-manager sessions.
			 */
			void acknowledge_wakeup();

			/**
			 * Return thread ID of last faulter
			 */
			Native_thread_id last() const { return _last; }

			/**
			 * Return badge for faulting thread
			 *
			 * As L4v4 has no server-defined badges for fault messages,
			 * we interpret the sender ID as badge.
			 */
			unsigned long badge() const { return _last.raw; }

			/**
			 * Return true if last fault was a write fault
			 */
			bool is_write_fault() const { return (_flags & 2); }

			/**
			 * Return true if last fault was an exception
			 */
			bool is_exception() const
			{
				/*
				 * Reflection of exceptions is not supported on this platform.
				 */
				return false;
			}
	};
}

#endif /* _INCLUDE__BASE__IPC_PAGER_H_ */