mempool.c

/*
 * File      : mempool.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2006-05-27     Bernard      implement memory pool
 * 2006-06-03     Bernard      fix the thread timer init bug
 * 2006-06-30     Bernard      fix the allocate/free block bug
 * 2006-08-04     Bernard      add hook support
 * 2006-08-10     Bernard      fix interrupt bug in rt_mp_alloc
 * 2010-07-13     Bernard      fix RT_ALIGN issue found by kuronca
 * 2010-10-26     yi.qiu       add module support in rt_mp_delete
 * 2011-01-24     Bernard      add object allocation check.
 * 2012-03-22     Bernard      fix align issue in rt_mp_init and rt_mp_create.
 */

#include <rthw.h>
#include <rtthread.h>

#ifdef RT_USING_MEMPOOL

#ifdef RT_USING_HOOK
static void (*rt_mp_alloc_hook)(struct rt_mempool *mp, void *block);
static void (*rt_mp_free_hook)(struct rt_mempool *mp, void *block);

/**
 * @addtogroup Hook
 */

/*@{*/

/**
 * This function will set a hook function, which will be invoked when a memory
 * block is allocated from memory pool.
 *
 * @param hook the hook function
 */
void rt_mp_alloc_sethook(void (*hook)(struct rt_mempool *mp, void *block))
{
	rt_mp_alloc_hook = hook;
}

/**
 * This function will set a hook function, which will be invoked when a memory
 * block is released to memory pool.
 *
 * @param hook the hook function
 */
void rt_mp_free_sethook(void (*hook)(struct rt_mempool *mp, void *block))
{
	rt_mp_free_hook = hook;
}

/*@}*/
#endif

/**
 * @addtogroup MM
 */

/*@{*/

/**
 * This function will initialize a memory pool object, normally which is used for
 * static object.
 *
 * @param mp the memory pool object
 * @param name the name of memory pool
 * @param start the star address of memory pool
 * @param size the total size of memory pool
 * @param block_size the size for each block
 *
 * @return RT_EOK
 */
rt_err_t rt_mp_init(struct rt_mempool *mp, const char *name, void *start, rt_size_t size, rt_size_t block_size)
{
	rt_uint8_t *block_ptr;
	register rt_base_t offset;

	/* parameter check */
	RT_ASSERT(mp != RT_NULL);

	/* initialize object */
	rt_object_init(&(mp->parent), RT_Object_Class_MemPool, name);

	/* initialize memory pool */
	mp->start_address = start;
	mp->size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);

	/* align the block size */
	block_size = RT_ALIGN(block_size, RT_ALIGN_SIZE);
	mp->block_size = block_size;

	/* align to align size byte */
	mp->block_total_count = mp->size / (mp->block_size + sizeof(rt_uint8_t *));
	mp->block_free_count = mp->block_total_count;

	/* initialize suspended thread list */
	rt_list_init(&(mp->suspend_thread));
	mp->suspend_thread_count = 0;

	/* initialize free block list */
	block_ptr = (rt_uint8_t *)mp->start_address;
	for (offset = 0; offset < mp->block_total_count; offset ++)
	{
		*(rt_uint8_t **)(block_ptr + offset * (block_size + sizeof(rt_uint8_t *)))
			= (rt_uint8_t *)(block_ptr + (offset + 1) * (block_size + sizeof(rt_uint8_t *)));
	}

	*(rt_uint8_t **)(block_ptr + (offset - 1) * (block_size + sizeof(rt_uint8_t *))) = RT_NULL;

	mp->block_list = block_ptr;

	return RT_EOK;
}
RTM_EXPORT(rt_mp_init);

/**
 * This function will detach a memory pool from system object management.
 *
 * @param mp the memory pool object
 *
 * @return RT_EOK
 */
rt_err_t rt_mp_detach(struct rt_mempool *mp)
{
	struct rt_thread *thread;
	register rt_ubase_t temp;

	/* parameter check */
	RT_ASSERT(mp != RT_NULL);

	/* wake up all suspended threads */
	while (!rt_list_isempty(&(mp->suspend_thread)))
	{
		/* disable interrupt */
		temp = rt_hw_interrupt_disable();

		/* get next suspend thread */
		thread = rt_list_entry(mp->suspend_thread.next, struct rt_thread, tlist);
		/* set error code to RT_ERROR */
		thread->error = -RT_ERROR;

		/*
		 * resume thread
		 * In rt_thread_resume function, it will remove current thread from suspend
		 * list
		 */
		rt_thread_resume(thread);

		/* decrease suspended thread count */
		mp->suspend_thread_count --;

		/* enable interrupt */
		rt_hw_interrupt_enable(temp);
	}

	/* detach object */
	rt_object_detach(&(mp->parent));

	return RT_EOK;
}
RTM_EXPORT(rt_mp_detach);

#ifdef RT_USING_HEAP
/**
 * This function will create a mempool object and allocate the memory pool from heap.
 *
 * @param name the name of memory pool
 * @param block_count the count of blocks in memory pool
 * @param block_size the size for each block
 *
 * @return the created mempool object
 */
rt_mp_t rt_mp_create(const char *name, rt_size_t block_count, rt_size_t block_size)
{
	rt_uint8_t *block_ptr;
	struct rt_mempool *mp;
	register rt_base_t offset;

	RT_DEBUG_NOT_IN_INTERRUPT;

	/* allocate object */
	mp = (struct rt_mempool *)rt_object_allocate(RT_Object_Class_MemPool, name);
	if (mp == RT_NULL)
		return RT_NULL; /* allocate object failed */

	/* initialize memory pool */
	block_size = RT_ALIGN(block_size, RT_ALIGN_SIZE);
	mp->block_size = block_size;
	mp->size = (block_size + sizeof(rt_uint8_t *)) * block_count;

	/* allocate memory */
	mp->start_address = rt_malloc((block_size + sizeof(rt_uint8_t *)) * block_count);
	if (mp->start_address == RT_NULL)
	{
		/* no memory, delete memory pool object */
		rt_object_delete(&(mp->parent));

		return RT_NULL;
	}

	mp->block_total_count = block_count;
	mp->block_free_count = mp->block_total_count;

	/* initialize suspended thread list */
	rt_list_init(&(mp->suspend_thread));
	mp->suspend_thread_count = 0;

	/* initialize free block list */
	block_ptr = (rt_uint8_t *)mp->start_address;
	for (offset = 0; offset < mp->block_total_count; offset ++)
	{
		*(rt_uint8_t **)(block_ptr + offset * (block_size + sizeof(rt_uint8_t *)))
			= block_ptr + (offset + 1) * (block_size + sizeof(rt_uint8_t *));
	}

	*(rt_uint8_t **)(block_ptr + (offset - 1) * (block_size + sizeof(rt_uint8_t *))) = RT_NULL;

	mp->block_list = block_ptr;

	return mp;
}
RTM_EXPORT(rt_mp_create);

/**
 * This function will delete a memory pool and release the object memory.
 *
 * @param mp the memory pool object
 *
 * @return RT_EOK
 */
rt_err_t rt_mp_delete(rt_mp_t mp)
{
	struct rt_thread *thread;
	register rt_ubase_t temp;

	RT_DEBUG_NOT_IN_INTERRUPT;

	/* parameter check */
	RT_ASSERT(mp != RT_NULL);

	/* wake up all suspended threads */
	while (!rt_list_isempty(&(mp->suspend_thread)))
	{
		/* disable interrupt */
		temp = rt_hw_interrupt_disable();

		/* get next suspend thread */
		thread = rt_list_entry(mp->suspend_thread.next, struct rt_thread, tlist);
		/* set error code to RT_ERROR */
		thread->error = -RT_ERROR;

		/*
		 * resume thread
		 * In rt_thread_resume function, it will remove current thread from suspend
		 * list
		 */
		rt_thread_resume(thread);

		/* decrease suspended thread count */
		mp->suspend_thread_count --;

		/* enable interrupt */
		rt_hw_interrupt_enable(temp);
	}

#if defined(RT_USING_MODULE) && defined(RT_USING_SLAB)
	/* the mp object belongs to an application module */
	if (mp->parent.flag & RT_OBJECT_FLAG_MODULE) 
		rt_module_free(mp->parent.module_id, mp->start_address);
	else
#endif

	/* release allocated room */
	rt_free(mp->start_address);

	/* detach object */
	rt_object_delete(&(mp->parent));

	return RT_EOK;
}
RTM_EXPORT(rt_mp_delete);
#endif

/**
 * This function will allocate a block from memory pool
 *
 * @param mp the memory pool object
 * @param time the waiting time
 *
 * @return the allocated memory block or RT_NULL on allocated failed
 */
void *rt_mp_alloc(rt_mp_t mp, rt_int32_t time)
{
	rt_uint8_t *block_ptr;
	register rt_base_t level;
	struct rt_thread *thread;

	/* disable interrupt */
	level = rt_hw_interrupt_disable();

	if (mp->block_free_count)
	{
		/* memory block is available. decrease the free block counter */
		mp->block_free_count --;

		/* get block from block list */
		block_ptr = mp->block_list;
		mp->block_list = *(rt_uint8_t **)block_ptr;

		/* point to memory pool */
		*(rt_uint8_t **)block_ptr = (rt_uint8_t *)mp;
	}
	else
	{
		/* memory block is unavailable. */
		if (time == 0)
		{
			/* enable interrupt */
			rt_hw_interrupt_enable(level);
			return RT_NULL;
		}
		else
		{
			RT_DEBUG_NOT_IN_INTERRUPT;

			/* get current thread */
			thread = rt_thread_self();

			/* need suspend thread */
			rt_thread_suspend(thread);
			rt_list_insert_after(&(mp->suspend_thread), &(thread->tlist));
			mp->suspend_thread_count ++;

			if (time > 0)
			{
				/* init thread timer and start it */
				rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &time);
				rt_timer_start(&(thread->thread_timer));
			}

			/* enable interrupt */
			rt_hw_interrupt_enable(level);

			/* do a schedule */
			rt_schedule();

			if (thread->error != RT_EOK)
				return RT_NULL;

			/* disable interrupt */
			level = rt_hw_interrupt_disable();

			/* decrease free block */
			mp->block_free_count --;

			/* get block from block list */
			block_ptr = mp->block_list;
			mp->block_list = *(rt_uint8_t **)block_ptr;

			/* point to memory pool */
			*(rt_uint8_t **)block_ptr = (rt_uint8_t *)mp;
		}
	}

	/* enable interrupt */
	rt_hw_interrupt_enable(level);

	RT_OBJECT_HOOK_CALL(rt_mp_alloc_hook, (mp, (rt_uint8_t *)(block_ptr + sizeof(rt_uint8_t *))));

	return (rt_uint8_t *)(block_ptr + sizeof(rt_uint8_t *));
}
RTM_EXPORT(rt_mp_alloc);

/**
 * This function will release a memory block
 *
 * @param block the address of memory block to be released
 */
void rt_mp_free(void *block)
{
	rt_uint8_t **block_ptr;
	struct rt_mempool *mp;
	struct rt_thread *thread;
	register rt_base_t level;

	/* get the control block of pool which the block belongs to */
	block_ptr = (rt_uint8_t **)((rt_uint8_t *)block - sizeof(rt_uint8_t *));
	mp = (struct rt_mempool *)*block_ptr;

	RT_OBJECT_HOOK_CALL(rt_mp_free_hook, (mp, block));

	/* disable interrupt */
	level = rt_hw_interrupt_disable();

	/* increase the free block count */
	mp->block_free_count ++;

	/* link the block into the block list */
	*block_ptr = mp->block_list;
	mp->block_list = (rt_uint8_t *)block_ptr;

	if (mp->suspend_thread_count > 0)
	{
		/* get the suspended thread */
		thread = rt_list_entry(mp->suspend_thread.next, struct rt_thread, tlist);

		/* set error */
		thread->error = RT_EOK;

		/* resume thread */
		rt_thread_resume(thread);

		/* decrease suspended thread count */
		mp->suspend_thread_count --;

		/* enable interrupt */
		rt_hw_interrupt_enable(level);

		/* do a schedule */
		rt_schedule();

		return;
	}

	/* enable interrupt */
	rt_hw_interrupt_enable(level);
}
RTM_EXPORT(rt_mp_free);

/*@}*/

#endif