/*
 * Copyright (C) 2010, 2012 ARM Limited. All rights reserved.
 * 
 * This program is free software and is provided to you under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation, and any use by you of this program is subject to the terms of such GNU licence.
 * 
 * A copy of the licence is included with the program, and can also be obtained from Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "mali_kernel_common.h"
#include "mali_kernel_descriptor_mapping.h"
#include "mali_osk.h"
#include "mali_osk_bitops.h"

#define MALI_PAD_INT(x) (((x) + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1))

/**
 * Allocate a descriptor table capable of holding 'count' mappings
 * @param count Number of mappings in the table
 * @return Pointer to a new table, NULL on error
 */
static mali_descriptor_table * descriptor_table_alloc(int count);

/**
 * Free a descriptor table
 * @param table The table to free
 */
static void descriptor_table_free(mali_descriptor_table * table);

mali_descriptor_mapping * mali_descriptor_mapping_create(int init_entries, int max_entries)
{
	mali_descriptor_mapping * map = _mali_osk_calloc(1, sizeof(mali_descriptor_mapping));

	init_entries = MALI_PAD_INT(init_entries);
	max_entries = MALI_PAD_INT(max_entries);

	if (NULL != map)
	{
		map->table = descriptor_table_alloc(init_entries);
		if (NULL != map->table)
		{
            map->lock = _mali_osk_lock_init( (_mali_osk_lock_flags_t)(_MALI_OSK_LOCKFLAG_ORDERED | _MALI_OSK_LOCKFLAG_READERWRITER | _MALI_OSK_LOCKFLAG_NONINTERRUPTABLE), 0, _MALI_OSK_LOCK_ORDER_DESCRIPTOR_MAP);
            if (NULL != map->lock)
            {
			    _mali_osk_set_nonatomic_bit(0, map->table->usage); /* reserve bit 0 to prevent NULL/zero logic to kick in */
			    map->max_nr_mappings_allowed = max_entries;
			    map->current_nr_mappings = init_entries;
			    return map;
            }
        	descriptor_table_free(map->table);
		}
		_mali_osk_free(map);
	}
	return NULL;
}

void mali_descriptor_mapping_destroy(mali_descriptor_mapping * map)
{
	descriptor_table_free(map->table);
    _mali_osk_lock_term(map->lock);
	_mali_osk_free(map);
}

_mali_osk_errcode_t mali_descriptor_mapping_allocate_mapping(mali_descriptor_mapping * map, void * target, int *odescriptor)
{
	_mali_osk_errcode_t err = _MALI_OSK_ERR_FAULT;
	int new_descriptor;

    MALI_DEBUG_ASSERT_POINTER(map);
    MALI_DEBUG_ASSERT_POINTER(odescriptor);

    _mali_osk_lock_wait(map->lock, _MALI_OSK_LOCKMODE_RW);
	new_descriptor = _mali_osk_find_first_zero_bit(map->table->usage, map->current_nr_mappings);
	if (new_descriptor == map->current_nr_mappings)
	{
		/* no free descriptor, try to expand the table */
		mali_descriptor_table * new_table, * old_table;
		if (map->current_nr_mappings >= map->max_nr_mappings_allowed) goto unlock_and_exit;

        map->current_nr_mappings += BITS_PER_LONG;
		new_table = descriptor_table_alloc(map->current_nr_mappings);
		if (NULL == new_table) goto unlock_and_exit;

        old_table = map->table;
		_mali_osk_memcpy(new_table->usage, old_table->usage, (sizeof(unsigned long)*map->current_nr_mappings) / BITS_PER_LONG);
		_mali_osk_memcpy(new_table->mappings, old_table->mappings, map->current_nr_mappings * sizeof(void*));
		map->table = new_table;
		descriptor_table_free(old_table);
	}

	/* we have found a valid descriptor, set the value and usage bit */
	_mali_osk_set_nonatomic_bit(new_descriptor, map->table->usage);
	map->table->mappings[new_descriptor] = target;
	*odescriptor = new_descriptor;
    err = _MALI_OSK_ERR_OK;

unlock_and_exit:
    _mali_osk_lock_signal(map->lock, _MALI_OSK_LOCKMODE_RW);
    MALI_ERROR(err);
}

void mali_descriptor_mapping_call_for_each(mali_descriptor_mapping * map, void (*callback)(int, void*))
{
	int i;

	MALI_DEBUG_ASSERT_POINTER(map);
	MALI_DEBUG_ASSERT_POINTER(callback);

    _mali_osk_lock_wait(map->lock, _MALI_OSK_LOCKMODE_RO);
	/* id 0 is skipped as it's an reserved ID not mapping to anything */
	for (i = 1; i < map->current_nr_mappings; ++i)
	{
		if (_mali_osk_test_bit(i, map->table->usage))
		{
			callback(i, map->table->mappings[i]);
		}
	}
    _mali_osk_lock_signal(map->lock, _MALI_OSK_LOCKMODE_RO);
}

_mali_osk_errcode_t mali_descriptor_mapping_get(mali_descriptor_mapping * map, int descriptor, void** target)
{
	_mali_osk_errcode_t result = _MALI_OSK_ERR_FAULT;
	MALI_DEBUG_ASSERT_POINTER(map);
    _mali_osk_lock_wait(map->lock, _MALI_OSK_LOCKMODE_RO);
	if ( (descriptor >= 0) && (descriptor < map->current_nr_mappings) && _mali_osk_test_bit(descriptor, map->table->usage) )
	{
		*target = map->table->mappings[descriptor];
		result = _MALI_OSK_ERR_OK;
	}
	else *target = NULL;
    _mali_osk_lock_signal(map->lock, _MALI_OSK_LOCKMODE_RO);
	MALI_ERROR(result);
}

_mali_osk_errcode_t mali_descriptor_mapping_set(mali_descriptor_mapping * map, int descriptor, void * target)
{
	_mali_osk_errcode_t result = _MALI_OSK_ERR_FAULT;
    _mali_osk_lock_wait(map->lock, _MALI_OSK_LOCKMODE_RO);
	if ( (descriptor >= 0) && (descriptor < map->current_nr_mappings) && _mali_osk_test_bit(descriptor, map->table->usage) )
	{
		map->table->mappings[descriptor] = target;
		result = _MALI_OSK_ERR_OK;
	}
    _mali_osk_lock_signal(map->lock, _MALI_OSK_LOCKMODE_RO);
	MALI_ERROR(result);
}

void *mali_descriptor_mapping_free(mali_descriptor_mapping * map, int descriptor)
{
	void *old_value = NULL;

    _mali_osk_lock_wait(map->lock, _MALI_OSK_LOCKMODE_RW);
	if ( (descriptor >= 0) && (descriptor < map->current_nr_mappings) && _mali_osk_test_bit(descriptor, map->table->usage) )
	{
		old_value = map->table->mappings[descriptor];
		map->table->mappings[descriptor] = NULL;
		_mali_osk_clear_nonatomic_bit(descriptor, map->table->usage);
	}
    _mali_osk_lock_signal(map->lock, _MALI_OSK_LOCKMODE_RW);

	return old_value;
}

static mali_descriptor_table * descriptor_table_alloc(int count)
{
	mali_descriptor_table * table;

	table = _mali_osk_calloc(1, sizeof(mali_descriptor_table) + ((sizeof(unsigned long) * count)/BITS_PER_LONG) + (sizeof(void*) * count));

	if (NULL != table)
	{
		table->usage = (u32*)((u8*)table + sizeof(mali_descriptor_table));
		table->mappings = (void**)((u8*)table + sizeof(mali_descriptor_table) + ((sizeof(unsigned long) * count)/BITS_PER_LONG));
	}

	return table;
}

static void descriptor_table_free(mali_descriptor_table * table)
{
	_mali_osk_free(table);
}