dma-mapping.c

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/*
 * SWIOTLB-based DMA API implementation
 *
 * Copyright (C) 2012 ARM Ltd.
 * Author: Catalin Marinas <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/swiotlb.h>

#include <asm/cacheflush.h>

struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);

static void *arm64_swiotlb_alloc_coherent(struct device *dev, size_t size,
                      dma_addr_t *dma_handle, gfp_t flags,
                      struct dma_attrs *attrs)
{
    if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
        dev->coherent_dma_mask <= DMA_BIT_MASK(32))
        flags |= GFP_DMA32;
    return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
}

static void arm64_swiotlb_free_coherent(struct device *dev, size_t size,
                    void *vaddr, dma_addr_t dma_handle,
                    struct dma_attrs *attrs)
{
    swiotlb_free_coherent(dev, size, vaddr, dma_handle);
}

static struct dma_map_ops arm64_swiotlb_dma_ops = {
    .alloc = arm64_swiotlb_alloc_coherent,
    .free = arm64_swiotlb_free_coherent,
    .map_page = swiotlb_map_page,
    .unmap_page = swiotlb_unmap_page,
    .map_sg = swiotlb_map_sg_attrs,
    .unmap_sg = swiotlb_unmap_sg_attrs,
    .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
    .sync_single_for_device = swiotlb_sync_single_for_device,
    .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
    .sync_sg_for_device = swiotlb_sync_sg_for_device,
    .dma_supported = swiotlb_dma_supported,
    .mapping_error = swiotlb_dma_mapping_error,
};

void __init arm64_swiotlb_init(void)
{
    dma_ops = &arm64_swiotlb_dma_ops;
    swiotlb_init(1);
}

#define PREALLOC_DMA_DEBUG_ENTRIES  4096

static int __init dma_debug_do_init(void)
{
    dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
    return 0;
}
fs_initcall(dma_debug_do_init);