/**************************************************************************** * include/nuttx/gran.h * General purpose granule memory allocator. * * Copyright (C) 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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_GRAN_H #define __INCLUDE_NUTTX_GRAN_H /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #ifdef CONFIG_GRAN /**************************************************************************** * Pre-Processor Definitions ****************************************************************************/ /* Configuration ************************************************************/ /* CONFIG_GRAN - Enable granual 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 ouput * 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 memory * and your hardware has specific memory alignment requirements. * * Geneneral 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 granual 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 * granual allocator interfaces. * ****************************************************************************/ #ifdef CONFIG_GRAN_SINGLE EXTERN int gran_initialize(FAR void *heapstart, size_t heapsize, uint8_t log2gran, uint8_t log2align); #else EXTERN GRAN_HANDLE gran_initialize(FAR void *heapstart, size_t heapsize, uint8_t log2gran, uint8_t log2align); #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 EXTERN FAR void *gran_alloc(size_t size); #else EXTERN 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 previoiusly allocated by gran_alloc. * * Returned Value: * None * ****************************************************************************/ #ifdef CONFIG_GRAN_SINGLE EXTERN void gran_free(FAR void *memory, size_t size); #else EXTERN void gran_free(GRAN_HANDLE handle, FAR void *memory, size_t size); #endif #undef EXTERN #ifdef __cplusplus } #endif #endif /* CONFIG_GRAN */ #endif /* __INCLUDE_NUTTX_GRAN_H */