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 *arm64_swiotlb_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 (IS_ENABLED(CONFIG_ZONE_DMA32) &&
  38             dev->coherent_dma_mask <= DMA_BIT_MASK(32))
  39                 flags |= GFP_DMA32;
  40         if (IS_ENABLED(CONFIG_DMA_CMA)) {
  41                 struct page *page;
  42
  43                 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
  44                                                         get_order(size));
  45                 if (!page)
  46                         return NULL;
  47
  48                 *dma_handle = phys_to_dma(dev, page_to_phys(page));
  49                 return page_address(page);
  50         } else {
  51                 return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
  52         }
  53 }
  54
  55 static void arm64_swiotlb_free_coherent(struct device *dev, size_t size,
  56                                         void *vaddr, dma_addr_t dma_handle,
  57                                         struct dma_attrs *attrs)
  58 {
  59         if (dev == NULL) {
  60                 WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
  61                 return;
  62         }
  63
  64         if (IS_ENABLED(CONFIG_DMA_CMA)) {
  65                 phys_addr_t paddr = dma_to_phys(dev, dma_handle);
  66
  67                 dma_release_from_contiguous(dev,
  68                                         phys_to_page(paddr),
  69                                         size >> PAGE_SHIFT);
  70         } else {
  71                 swiotlb_free_coherent(dev, size, vaddr, dma_handle);
  72         }
  73 }
  74
  75 static struct dma_map_ops arm64_swiotlb_dma_ops = {
  76         .alloc = arm64_swiotlb_alloc_coherent,
  77         .free = arm64_swiotlb_free_coherent,
  78         .map_page = swiotlb_map_page,
  79         .unmap_page = swiotlb_unmap_page,
  80         .map_sg = swiotlb_map_sg_attrs,
  81         .unmap_sg = swiotlb_unmap_sg_attrs,
  82         .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  83         .sync_single_for_device = swiotlb_sync_single_for_device,
  84         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  85         .sync_sg_for_device = swiotlb_sync_sg_for_device,
  86         .dma_supported = swiotlb_dma_supported,
  87         .mapping_error = swiotlb_dma_mapping_error,
  88 };
  89
  90 void __init arm64_swiotlb_init(void)
  91 {
  92         dma_ops = &arm64_swiotlb_dma_ops;
  93         swiotlb_init(1);
  94 }
  95
  96 #define PREALLOC_DMA_DEBUG_ENTRIES      4096
  97
  98 static int __init dma_debug_do_init(void)
  99 {
 100         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 101         return 0;
 102 }
 103 fs_initcall(dma_debug_do_init);