arch/xtensa/kernel/pci-dma.c

   1 /*
   2  * DMA coherent memory allocation.
   3  *
   4  * This program is free software; you can redistribute  it and/or modify it
   5  * under  the terms of  the GNU General  Public License as published by the
   6  * Free Software Foundation;  either version 2 of the  License, or (at your
   7  * option) any later version.
   8  *
   9  * Copyright (C) 2002 - 2005 Tensilica Inc.
  10  * Copyright (C) 2015 Cadence Design Systems Inc.
  11  *
  12  * Based on version for i386.
  13  *
  14  * Chris Zankel <chris@zankel.net>
  15  * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
  16  */
  17
  18 #include <linux/types.h>
  19 #include <linux/mm.h>
  20 #include <linux/string.h>
  21 #include <linux/pci.h>
  22 #include <linux/gfp.h>
  23 #include <linux/module.h>
  24 #include <asm/io.h>
  25 #include <asm/cacheflush.h>
  26
  27 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  28                     enum dma_data_direction dir)
  29 {
  30         switch (dir) {
  31         case DMA_BIDIRECTIONAL:
  32                 __flush_invalidate_dcache_range((unsigned long)vaddr, size);
  33                 break;
  34
  35         case DMA_FROM_DEVICE:
  36                 __invalidate_dcache_range((unsigned long)vaddr, size);
  37                 break;
  38
  39         case DMA_TO_DEVICE:
  40                 __flush_dcache_range((unsigned long)vaddr, size);
  41                 break;
  42
  43         case DMA_NONE:
  44                 BUG();
  45                 break;
  46         }
  47 }
  48 EXPORT_SYMBOL(dma_cache_sync);
  49
  50 static void xtensa_sync_single_for_cpu(struct device *dev,
  51                                        dma_addr_t dma_handle, size_t size,
  52                                        enum dma_data_direction dir)
  53 {
  54         void *vaddr;
  55
  56         switch (dir) {
  57         case DMA_BIDIRECTIONAL:
  58         case DMA_FROM_DEVICE:
  59                 vaddr = bus_to_virt(dma_handle);
  60                 __invalidate_dcache_range((unsigned long)vaddr, size);
  61                 break;
  62
  63         case DMA_NONE:
  64                 BUG();
  65                 break;
  66
  67         default:
  68                 break;
  69         }
  70 }
  71
  72 static void xtensa_sync_single_for_device(struct device *dev,
  73                                           dma_addr_t dma_handle, size_t size,
  74                                           enum dma_data_direction dir)
  75 {
  76         void *vaddr;
  77
  78         switch (dir) {
  79         case DMA_BIDIRECTIONAL:
  80         case DMA_TO_DEVICE:
  81                 vaddr = bus_to_virt(dma_handle);
  82                 __flush_dcache_range((unsigned long)vaddr, size);
  83                 break;
  84
  85         case DMA_NONE:
  86                 BUG();
  87                 break;
  88
  89         default:
  90                 break;
  91         }
  92 }
  93
  94 static void xtensa_sync_sg_for_cpu(struct device *dev,
  95                                    struct scatterlist *sg, int nents,
  96                                    enum dma_data_direction dir)
  97 {
  98         struct scatterlist *s;
  99         int i;
 100
 101         for_each_sg(sg, s, nents, i) {
 102                 xtensa_sync_single_for_cpu(dev, sg_dma_address(s),
 103                                            sg_dma_len(s), dir);
 104         }
 105 }
 106
 107 static void xtensa_sync_sg_for_device(struct device *dev,
 108                                       struct scatterlist *sg, int nents,
 109                                       enum dma_data_direction dir)
 110 {
 111         struct scatterlist *s;
 112         int i;
 113
 114         for_each_sg(sg, s, nents, i) {
 115                 xtensa_sync_single_for_device(dev, sg_dma_address(s),
 116                                               sg_dma_len(s), dir);
 117         }
 118 }
 119
 120 /*
 121  * Note: We assume that the full memory space is always mapped to 'kseg'
 122  *       Otherwise we have to use page attributes (not implemented).
 123  */
 124
 125 static void *xtensa_dma_alloc(struct device *dev, size_t size,
 126                               dma_addr_t *handle, gfp_t flag,
 127                               struct dma_attrs *attrs)
 128 {
 129         unsigned long ret;
 130         unsigned long uncached = 0;
 131
 132         /* ignore region speicifiers */
 133
 134         flag &= ~(__GFP_DMA | __GFP_HIGHMEM);
 135
 136         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
 137                 flag |= GFP_DMA;
 138         ret = (unsigned long)__get_free_pages(flag, get_order(size));
 139
 140         if (ret == 0)
 141                 return NULL;
 142
 143         /* We currently don't support coherent memory outside KSEG */
 144
 145         BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
 146                ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 147
 148         uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
 149         *handle = virt_to_bus((void *)ret);
 150         __invalidate_dcache_range(ret, size);
 151
 152         return (void *)uncached;
 153 }
 154
 155 static void xtensa_dma_free(struct device *hwdev, size_t size, void *vaddr,
 156                             dma_addr_t dma_handle, struct dma_attrs *attrs)
 157 {
 158         unsigned long addr = (unsigned long)vaddr +
 159                 XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
 160
 161         BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
 162                addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 163
 164         free_pages(addr, get_order(size));
 165 }
 166
 167 static dma_addr_t xtensa_map_page(struct device *dev, struct page *page,
 168                                   unsigned long offset, size_t size,
 169                                   enum dma_data_direction dir,
 170                                   struct dma_attrs *attrs)
 171 {
 172         dma_addr_t dma_handle = page_to_phys(page) + offset;
 173
 174         BUG_ON(PageHighMem(page));
 175         xtensa_sync_single_for_device(dev, dma_handle, size, dir);
 176         return dma_handle;
 177 }
 178
 179 static void xtensa_unmap_page(struct device *dev, dma_addr_t dma_handle,
 180                               size_t size, enum dma_data_direction dir,
 181                               struct dma_attrs *attrs)
 182 {
 183         xtensa_sync_single_for_cpu(dev, dma_handle, size, dir);
 184 }
 185
 186 static int xtensa_map_sg(struct device *dev, struct scatterlist *sg,
 187                          int nents, enum dma_data_direction dir,
 188                          struct dma_attrs *attrs)
 189 {
 190         struct scatterlist *s;
 191         int i;
 192
 193         for_each_sg(sg, s, nents, i) {
 194                 s->dma_address = xtensa_map_page(dev, sg_page(s), s->offset,
 195                                                  s->length, dir, attrs);
 196         }
 197         return nents;
 198 }
 199
 200 static void xtensa_unmap_sg(struct device *dev,
 201                             struct scatterlist *sg, int nents,
 202                             enum dma_data_direction dir,
 203                             struct dma_attrs *attrs)
 204 {
 205         struct scatterlist *s;
 206         int i;
 207
 208         for_each_sg(sg, s, nents, i) {
 209                 xtensa_unmap_page(dev, sg_dma_address(s),
 210                                   sg_dma_len(s), dir, attrs);
 211         }
 212 }
 213
 214 int xtensa_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 215 {
 216         return 0;
 217 }
 218
 219 struct dma_map_ops xtensa_dma_map_ops = {
 220         .alloc = xtensa_dma_alloc,
 221         .free = xtensa_dma_free,
 222         .map_page = xtensa_map_page,
 223         .unmap_page = xtensa_unmap_page,
 224         .map_sg = xtensa_map_sg,
 225         .unmap_sg = xtensa_unmap_sg,
 226         .sync_single_for_cpu = xtensa_sync_single_for_cpu,
 227         .sync_single_for_device = xtensa_sync_single_for_device,
 228         .sync_sg_for_cpu = xtensa_sync_sg_for_cpu,
 229         .sync_sg_for_device = xtensa_sync_sg_for_device,
 230         .mapping_error = xtensa_dma_mapping_error,
 231 };
 232 EXPORT_SYMBOL(xtensa_dma_map_ops);
 233
 234 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 235
 236 static int __init xtensa_dma_init(void)
 237 {
 238         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 239         return 0;
 240 }
 241 fs_initcall(xtensa_dma_init);