/*
 * \brief  Mapping of Genode's capability names to kernel capabilities.
 * \author Alexander Boettcher
 * \date   2013-08-26
 */

/*
 * Copyright (C) 2013-2013 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.
 */

#include <base/cap_map.h>

/* base-nova specific include */
#include <nova/syscalls.h>

using namespace Genode;


Capability_map *Genode::cap_map() {
	static Genode::Capability_map map;
	return &map;
}


/***********************
 **  Cap_index class  **
 ***********************/


Cap_range *Cap_range::find_by_id(addr_t id)
{
	if (_match(id)) return this;

	Cap_range *obj = this->child(id > _base);
	return obj ? obj->find_by_id(id) : 0;
}


void Cap_range::inc(unsigned id, bool inc_if_one) {

	Lock::Guard guard(_lock);

	if (inc_if_one && _cap_array[id] != 1)
		return;

	if (_cap_array[id] == 255) {
//		PERR("cap overflow - selector %lx - return address %p",
//		     _base + id, __builtin_return_address(0));
		*reinterpret_cast<addr_t *>(0) = 0xdead;
	}

	_cap_array[id]++;
}


void Cap_range::dec(unsigned id, bool revoke) {

	Lock::Guard guard(_lock);

	if (_cap_array[id] == 0)
		*reinterpret_cast<addr_t *>(0) = 0xdead;

	if (revoke && _cap_array[id] == 1)
		Nova::revoke(Nova::Obj_crd(_base + id, 0));

	_cap_array[id]--;
}


addr_t Cap_range::alloc(size_t const num_log2)
{
	addr_t const step = 1UL << num_log2;

	{
		Lock::Guard guard(_lock);

		unsigned max  = elements();
		addr_t   last = _last;

		do {

			/* align i to num_log2 */
			unsigned i = ((_base + last + step - 1) & ~(step - 1)) - _base;
			unsigned j;
			for (; i + step < max; i += step) {
				for (j = 0; j < step; j++)
					if (_cap_array[i+j])
						break;
				if (j < step)
					continue;

				for (j = 0; j < step; j++)
					_cap_array[i+j] = 1;

				_last = i;
				return _base + i;
			}

			max  = last;
			last = 0;

		} while (max);
	}

	Cap_range *child = this->child(LEFT);
	if (child) {
		addr_t res = child->alloc(num_log2);
		if (res != ~0UL)
			return res;
	}
	child = this->child(RIGHT);
	if (child) {
		addr_t res = child->alloc(num_log2);
		return res;
	}

	return ~0UL;
}


/****************************
 **  Capability_map class  **
 ****************************/


Cap_index Capability_map::find(Genode::addr_t id) {
	return Cap_index(_tree.first() ? _tree.first()->find_by_id(id) : 0, id); }


addr_t Capability_map::insert(size_t const num_log_2, addr_t const sel)
{
	if (sel == ~0UL)
		return _tree.first() ? _tree.first()->alloc(num_log_2) : ~0UL;

	Cap_range * range = _tree.first() ? _tree.first()->find_by_id(sel) : 0;
	if (!range)
		return ~0UL;

	for (unsigned i = 0; i < 1UL << num_log_2; i++)
		range->inc(sel + i - range->base());

	return sel;
}


void Capability_map::remove(Genode::addr_t sel, uint8_t num_log_2, bool revoke)
{
	Cap_range * range = _tree.first() ? _tree.first()->find_by_id(sel) : 0;
	if (!range)
		return;

	for (unsigned i = 0; i < 1UL << num_log_2; i++)
		range->dec(sel + i - range->base(), revoke);
}