arch/arm64/mm/dma-mapping.c

   1 /*
   2  * SWIOTLB-based DMA API implementation
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  * Author: Catalin Marinas <catalin.marinas@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/gfp.h>
  21 #include <linux/export.h>
  22 #include <linux/slab.h>
  23 #include <linux/dma-mapping.h>
  24 #include <linux/dma-contiguous.h>
  25 #include <linux/vmalloc.h>
  26 #include <linux/swiotlb.h>
  27
  28 #include <asm/cacheflush.h>
  29
  30 struct dma_map_ops *dma_ops;
  31 EXPORT_SYMBOL(dma_ops);
  32
  33 static void *__dma_alloc_coherent(struct device *dev, size_t size,
  34                                   dma_addr_t *dma_handle, gfp_t flags,
  35                                   struct dma_attrs *attrs)
  36 {
  37         if (dev == NULL) {
  38                 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
  39                 return NULL;
  40         }
  41
  42         if (IS_ENABLED(CONFIG_ZONE_DMA) &&
  43             dev->coherent_dma_mask <= DMA_BIT_MASK(32))
  44                 flags |= GFP_DMA;
  45         if (IS_ENABLED(CONFIG_DMA_CMA)) {
  46                 struct page *page;
  47
  48                 size = PAGE_ALIGN(size);
  49                 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
  50                                                         get_order(size));
  51                 if (!page)
  52                         return NULL;
  53
  54                 *dma_handle = phys_to_dma(dev, page_to_phys(page));
  55                 return page_address(page);
  56         } else {
  57                 return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
  58         }
  59 }
  60
  61 static void __dma_free_coherent(struct device *dev, size_t size,
  62                                 void *vaddr, dma_addr_t dma_handle,
  63                                 struct dma_attrs *attrs)
  64 {
  65         if (dev == NULL) {
  66                 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
  67                 return;
  68         }
  69
  70         if (IS_ENABLED(CONFIG_DMA_CMA)) {
  71                 phys_addr_t paddr = dma_to_phys(dev, dma_handle);
  72
  73                 dma_release_from_contiguous(dev,
  74                                         phys_to_page(paddr),
  75                                         size >> PAGE_SHIFT);
  76         } else {
  77                 swiotlb_free_coherent(dev, size, vaddr, dma_handle);
  78         }
  79 }
  80
  81 static struct dma_map_ops coherent_swiotlb_dma_ops = {
  82         .alloc = __dma_alloc_coherent,
  83         .free = __dma_free_coherent,
  84         .map_page = swiotlb_map_page,
  85         .unmap_page = swiotlb_unmap_page,
  86         .map_sg = swiotlb_map_sg_attrs,
  87         .unmap_sg = swiotlb_unmap_sg_attrs,
  88         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  89         .sync_single_for_device = swiotlb_sync_single_for_device,
  90         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  91         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  92         .dma_supported = swiotlb_dma_supported,
  93         .mapping_error = swiotlb_dma_mapping_error,
  94 };
  95
  96 void __init arm64_swiotlb_init(void)
  97 {
  98         dma_ops = &coherent_swiotlb_dma_ops;
  99         swiotlb_init(1);
 100 }
 101
 102 #define PREALLOC_DMA_DEBUG_ENTRIES      4096
 103
 104 static int __init dma_debug_do_init(void)
 105 {
 106         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 107         return 0;
 108 }
 109 fs_initcall(dma_debug_do_init);