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/****************************************************************************
* include/nuttx/mm/gran.h
* General purpose granule memory allocator.
*
* Copyright (C) 2012, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_MM_GRAN_H
#define __INCLUDE_NUTTX_MM_GRAN_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#ifdef CONFIG_GRAN
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* CONFIG_GRAN - Enable granule allocator support
* CONFIG_GRAN_SINGLE - Select if there is only one instance of the
* granule allocator (i.e., gran_initialize will be called only once.
* In this case, (1) there are a few optimizations that can can be done
* and (2) the GRAN_HANDLE is not needed.
* CONFIG_GRAN_INTR - Normally mutual exclusive access to granule allocator
* data is assured using a semaphore. If this option is set then, instead,
* mutual exclusion logic will disable interrupts. While this options is
* more invasive to system performance, it will also support use of the
* granule allocator from interrupt level logic.
* CONFIG_DEBUG_GRAN - Just like CONFIG_DEBUG_MM, but only generates output
* from the gran allocation logic.
*/
/****************************************************************************
* Public Types
****************************************************************************/
#ifndef CONFIG_GRAN_SINGLE
typedef FAR void *GRAN_HANDLE;
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Name: gran_initialize
*
* Description:
* Set up one granule allocator instance. Allocations will be aligned to
* the alignment size (log2align; allocations will be in units of the
* granule size (log2gran). Larger granules will give better performance
* and less overhead but more losses of memory due to quantization waste.
* Additional memory waste can occur from alignment; log2align should be
* set to 0 unless you are using the granule allocator to manage DMA
* or page-aligned memory and your hardware has specific memory alignment
* requirements.
*
* General Usage Summary. This is an example using the GCC section
* attribute to position a DMA heap in memory (logic in the linker script
* would assign the section .dmaheap to the DMA memory.
*
* FAR uint32_t g_dmaheap[DMAHEAP_SIZE] __attribute__((section(.dmaheap)));
*
* The heap is created by calling gran_initialize. Here the granule size
* is set to 64 bytes and the alignment to 16 bytes:
*
* GRAN_HANDLE handle = gran_initialize(g_dmaheap, DMAHEAP_SIZE, 6, 4);
*
* Then the GRAN_HANDLE can be used to allocate memory (There is no
* GRAN_HANDLE if CONFIG_GRAN_SINGLE=y):
*
* FAR uint8_t *dma_memory = (FAR uint8_t *)gran_alloc(handle, 47);
*
* The actual memory allocates will be 64 byte (wasting 17 bytes) and
* will be aligned at least to (1 << log2align).
*
* NOTE: The current implementation also restricts the maximum allocation
* size to 32 granules. That restriction could be eliminated with some
* additional coding effort.
*
* Input Parameters:
* heapstart - Start of the granule allocation heap
* heapsize - Size of heap in bytes
* log2gran - Log base 2 of the size of one granule. 0->1 byte,
* 1->2 bytes, 2->4 bytes, 3->8 bytes, etc.
* log2align - Log base 2 of required alignment. 0->1 byte,
* 1->2 bytes, 2->4 bytes, 3->8 bytes, etc. Note that
* log2gran must be greater than or equal to log2align
* so that all contiguous granules in memory will meet
* the minimum alignment requirement. A value of zero
* would mean that no alignment is required.
*
* Returned Value:
* On success, a non-NULL handle is returned that may be used with other
* granule allocator interfaces.
*
****************************************************************************/
#ifdef CONFIG_GRAN_SINGLE
int gran_initialize(FAR void *heapstart, size_t heapsize, uint8_t log2gran,
uint8_t log2align);
#else
GRAN_HANDLE gran_initialize(FAR void *heapstart, size_t heapsize,
uint8_t log2gran, uint8_t log2align);
#endif
/****************************************************************************
* Name: gran_release
*
* Description:
* Uninitialize a gram memory allocator and release resources held by the
* allocator.
*
* Input Parameters:
* handle - The handle previously returned by gran_initialize
*
* Returned Value:
* None.
*
****************************************************************************/
#ifdef CONFIG_GRAN_SINGLE
void gran_release(void);
#else
void gran_release(GRAN_HANDLE handle);
#endif
/****************************************************************************
* Name: gran_reserve
*
* Description:
* Reserve memory in the granule heap. This will reserve the granules
* that contain the start and end addresses plus all of the granules
* in between. This should be done early in the initialization sequence
* before any other allocations are made.
*
* Reserved memory can never be allocated (it can be freed however which
* essentially unreserves the memory).
*
* Input Parameters:
* handle - The handle previously returned by gran_initialize
* start - The address of the beginning of the region to be reserved.
* size - The size of the region to be reserved
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_GRAN_SINGLE
void gran_reserve(uintptr_t start, size_t size);
#else
void gran_reserve(GRAN_HANDLE handle, uintptr_t start, size_t size);
#endif
/****************************************************************************
* Name: gran_alloc
*
* Description:
* Allocate memory from the granule heap.
*
* NOTE: The current implementation also restricts the maximum allocation
* size to 32 granules. That restriction could be eliminated with some
* additional coding effort.
*
* Input Parameters:
* handle - The handle previously returned by gran_initialize
* size - The size of the memory region to allocate.
*
* Returned Value:
* On success, either a non-NULL pointer to the allocated memory (if
* CONFIG_GRAN_SINGLE) or zero (if !CONFIG_GRAN_SINGLE) is returned.
*
****************************************************************************/
#ifdef CONFIG_GRAN_SINGLE
FAR void *gran_alloc(size_t size);
#else
FAR void *gran_alloc(GRAN_HANDLE handle, size_t size);
#endif
/****************************************************************************
* Name: gran_free
*
* Description:
* Return memory to the granule heap.
*
* Input Parameters:
* handle - The handle previously returned by gran_initialize
* memory - A pointer to memory previously allocated by gran_alloc.
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_GRAN_SINGLE
void gran_free(FAR void *memory, size_t size);
#else
void gran_free(GRAN_HANDLE handle, FAR void *memory, size_t size);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_GRAN */
#endif /* __INCLUDE_NUTTX_MM_GRAN_H */
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