arch/microblaze/kernel/dma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2009-2010 PetaLogix
   4  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   5  *
   6  * Provide default implementations of the DMA mapping callbacks for
   7  * directly mapped busses.
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/gfp.h>
  13 #include <linux/dma-debug.h>
  14 #include <linux/export.h>
  15 #include <linux/bug.h>
  16 #include <asm/cacheflush.h>
  17
  18 static void *dma_nommu_alloc_coherent(struct device *dev, size_t size,
  19                                        dma_addr_t *dma_handle, gfp_t flag,
  20                                        unsigned long attrs)
  21 {
  22         return consistent_alloc(flag, size, dma_handle);
  23 }
  24
  25 static void dma_nommu_free_coherent(struct device *dev, size_t size,
  26                                      void *vaddr, dma_addr_t dma_handle,
  27                                      unsigned long attrs)
  28 {
  29         consistent_free(size, vaddr);
  30 }
  31
  32 static inline void __dma_sync(unsigned long paddr,
  33                               size_t size, enum dma_data_direction direction)
  34 {
  35         switch (direction) {
  36         case DMA_TO_DEVICE:
  37         case DMA_BIDIRECTIONAL:
  38                 flush_dcache_range(paddr, paddr + size);
  39                 break;
  40         case DMA_FROM_DEVICE:
  41                 invalidate_dcache_range(paddr, paddr + size);
  42                 break;
  43         default:
  44                 BUG();
  45         }
  46 }
  47
  48 static int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,
  49                              int nents, enum dma_data_direction direction,
  50                              unsigned long attrs)
  51 {
  52         struct scatterlist *sg;
  53         int i;
  54
  55         /* FIXME this part of code is untested */
  56         for_each_sg(sgl, sg, nents, i) {
  57                 sg->dma_address = sg_phys(sg);
  58
  59                 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
  60                         continue;
  61
  62                 __dma_sync(sg_phys(sg), sg->length, direction);
  63         }
  64
  65         return nents;
  66 }
  67
  68 static inline dma_addr_t dma_nommu_map_page(struct device *dev,
  69                                              struct page *page,
  70                                              unsigned long offset,
  71                                              size_t size,
  72                                              enum dma_data_direction direction,
  73                                              unsigned long attrs)
  74 {
  75         if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
  76                 __dma_sync(page_to_phys(page) + offset, size, direction);
  77         return page_to_phys(page) + offset;
  78 }
  79
  80 static inline void dma_nommu_unmap_page(struct device *dev,
  81                                          dma_addr_t dma_address,
  82                                          size_t size,
  83                                          enum dma_data_direction direction,
  84                                          unsigned long attrs)
  85 {
  86 /* There is not necessary to do cache cleanup
  87  *
  88  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
  89  * dma_address is physical address
  90  */
  91         if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
  92                 __dma_sync(dma_address, size, direction);
  93 }
  94
  95 static inline void
  96 dma_nommu_sync_single_for_cpu(struct device *dev,
  97                                dma_addr_t dma_handle, size_t size,
  98                                enum dma_data_direction direction)
  99 {
 100         /*
 101          * It's pointless to flush the cache as the memory segment
 102          * is given to the CPU
 103          */
 104
 105         if (direction == DMA_FROM_DEVICE)
 106                 __dma_sync(dma_handle, size, direction);
 107 }
 108
 109 static inline void
 110 dma_nommu_sync_single_for_device(struct device *dev,
 111                                   dma_addr_t dma_handle, size_t size,
 112                                   enum dma_data_direction direction)
 113 {
 114         /*
 115          * It's pointless to invalidate the cache if the device isn't
 116          * supposed to write to the relevant region
 117          */
 118
 119         if (direction == DMA_TO_DEVICE)
 120                 __dma_sync(dma_handle, size, direction);
 121 }
 122
 123 static inline void
 124 dma_nommu_sync_sg_for_cpu(struct device *dev,
 125                            struct scatterlist *sgl, int nents,
 126                            enum dma_data_direction direction)
 127 {
 128         struct scatterlist *sg;
 129         int i;
 130
 131         /* FIXME this part of code is untested */
 132         if (direction == DMA_FROM_DEVICE)
 133                 for_each_sg(sgl, sg, nents, i)
 134                         __dma_sync(sg->dma_address, sg->length, direction);
 135 }
 136
 137 static inline void
 138 dma_nommu_sync_sg_for_device(struct device *dev,
 139                               struct scatterlist *sgl, int nents,
 140                               enum dma_data_direction direction)
 141 {
 142         struct scatterlist *sg;
 143         int i;
 144
 145         /* FIXME this part of code is untested */
 146         if (direction == DMA_TO_DEVICE)
 147                 for_each_sg(sgl, sg, nents, i)
 148                         __dma_sync(sg->dma_address, sg->length, direction);
 149 }
 150
 151 static
 152 int dma_nommu_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
 153                              void *cpu_addr, dma_addr_t handle, size_t size,
 154                              unsigned long attrs)
 155 {
 156 #ifdef CONFIG_MMU
 157         unsigned long user_count = vma_pages(vma);
 158         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 159         unsigned long off = vma->vm_pgoff;
 160         unsigned long pfn;
 161
 162         if (off >= count || user_count > (count - off))
 163                 return -ENXIO;
 164
 165         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 166         pfn = consistent_virt_to_pfn(cpu_addr);
 167         return remap_pfn_range(vma, vma->vm_start, pfn + off,
 168                                vma->vm_end - vma->vm_start, vma->vm_page_prot);
 169 #else
 170         return -ENXIO;
 171 #endif
 172 }
 173
 174 const struct dma_map_ops dma_nommu_ops = {
 175         .alloc                  = dma_nommu_alloc_coherent,
 176         .free                   = dma_nommu_free_coherent,
 177         .mmap                   = dma_nommu_mmap_coherent,
 178         .map_sg                 = dma_nommu_map_sg,
 179         .map_page               = dma_nommu_map_page,
 180         .unmap_page             = dma_nommu_unmap_page,
 181         .sync_single_for_cpu    = dma_nommu_sync_single_for_cpu,
 182         .sync_single_for_device = dma_nommu_sync_single_for_device,
 183         .sync_sg_for_cpu        = dma_nommu_sync_sg_for_cpu,
 184         .sync_sg_for_device     = dma_nommu_sync_sg_for_device,
 185 };
 186 EXPORT_SYMBOL(dma_nommu_ops);