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Release 4.12 include/linux/dma-contiguous.h

Directory: include/linux
#ifndef __LINUX_CMA_H

#define __LINUX_CMA_H

/*
 * Contiguous Memory Allocator for DMA mapping framework
 * Copyright (c) 2010-2011 by Samsung Electronics.
 * Written by:
 *      Marek Szyprowski <m.szyprowski@samsung.com>
 *      Michal Nazarewicz <mina86@mina86.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License or (at your optional) any later version of the license.
 */

/*
 * Contiguous Memory Allocator
 *
 *   The Contiguous Memory Allocator (CMA) makes it possible to
 *   allocate big contiguous chunks of memory after the system has
 *   booted.
 *
 * Why is it needed?
 *
 *   Various devices on embedded systems have no scatter-getter and/or
 *   IO map support and require contiguous blocks of memory to
 *   operate.  They include devices such as cameras, hardware video
 *   coders, etc.
 *
 *   Such devices often require big memory buffers (a full HD frame
 *   is, for instance, more then 2 mega pixels large, i.e. more than 6
 *   MB of memory), which makes mechanisms such as kmalloc() or
 *   alloc_page() ineffective.
 *
 *   At the same time, a solution where a big memory region is
 *   reserved for a device is suboptimal since often more memory is
 *   reserved then strictly required and, moreover, the memory is
 *   inaccessible to page system even if device drivers don't use it.
 *
 *   CMA tries to solve this issue by operating on memory regions
 *   where only movable pages can be allocated from.  This way, kernel
 *   can use the memory for pagecache and when device driver requests
 *   it, allocated pages can be migrated.
 *
 * Driver usage
 *
 *   CMA should not be used by the device drivers directly. It is
 *   only a helper framework for dma-mapping subsystem.
 *
 *   For more information, see kernel-docs in drivers/base/dma-contiguous.c
 */

#ifdef __KERNEL__

#include <linux/device.h>

struct cma;
struct page;

#ifdef CONFIG_DMA_CMA

extern struct cma *dma_contiguous_default_area;


static inline struct cma *dev_get_cma_area(struct device *dev) { if (dev && dev->cma_area) return dev->cma_area; return dma_contiguous_default_area; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski30100.00%1100.00%
Total30100.00%1100.00%


static inline void dev_set_cma_area(struct device *dev, struct cma *cma) { if (dev) dev->cma_area = cma; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski27100.00%1100.00%
Total27100.00%1100.00%


static inline void dma_contiguous_set_default(struct cma *cma) { dma_contiguous_default_area = cma; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski16100.00%1100.00%
Total16100.00%1100.00%

void dma_contiguous_reserve(phys_addr_t addr_limit); int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, phys_addr_t limit, struct cma **res_cma, bool fixed); /** * dma_declare_contiguous() - reserve area for contiguous memory handling * for particular device * @dev: Pointer to device structure. * @size: Size of the reserved memory. * @base: Start address of the reserved memory (optional, 0 for any). * @limit: End address of the reserved memory (optional, 0 for any). * * This function reserves memory for specified device. It should be * called by board specific code when early allocator (memblock or bootmem) * is still activate. */
static inline int dma_declare_contiguous(struct device *dev, phys_addr_t size, phys_addr_t base, phys_addr_t limit) { struct cma *cma; int ret; ret = dma_contiguous_reserve_area(size, base, limit, &cma, true); if (ret == 0) dev_set_cma_area(dev, cma); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski5895.08%250.00%
Akinobu Mita23.28%125.00%
Vitaly Andrianov11.64%125.00%
Total61100.00%4100.00%

struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, unsigned int order, gfp_t gfp_mask); bool dma_release_from_contiguous(struct device *dev, struct page *pages, int count); #else
static inline struct cma *dev_get_cma_area(struct device *dev) { return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski17100.00%1100.00%
Total17100.00%1100.00%


static inline void dev_set_cma_area(struct device *dev, struct cma *cma) { }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski16100.00%1100.00%
Total16100.00%1100.00%


static inline void dma_contiguous_set_default(struct cma *cma) { }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski11100.00%1100.00%
Total11100.00%1100.00%


static inline void dma_contiguous_reserve(phys_addr_t limit) { }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski9100.00%1100.00%
Total9100.00%1100.00%


static inline int dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, phys_addr_t limit, struct cma **res_cma, bool fixed) { return -ENOSYS; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski2689.66%150.00%
Akinobu Mita310.34%150.00%
Total29100.00%2100.00%


static inline int dma_declare_contiguous(struct device *dev, phys_addr_t size, phys_addr_t base, phys_addr_t limit) { return -ENOSYS; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski2496.00%150.00%
Vitaly Andrianov14.00%150.00%
Total25100.00%2100.00%


static inline struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, unsigned int order, gfp_t gfp_mask) { return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski2385.19%133.33%
Lucas Stach311.11%133.33%
Rohit Vaswani13.70%133.33%
Total27100.00%3100.00%


static inline bool dma_release_from_contiguous(struct device *dev, struct page *pages, int count) { return false; }

Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski23100.00%1100.00%
Total23100.00%1100.00%

#endif #endif #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Marek Szyprowski37594.46%225.00%
Akinobu Mita82.02%112.50%
Lucas Stach61.51%112.50%
JoonSoo Kim30.76%112.50%
Vitaly Andrianov20.50%112.50%
Rohit Vaswani20.50%112.50%
Aneesh Kumar K.V10.25%112.50%
Total397100.00%8100.00%
Directory: include/linux
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