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/gfp.h>
  19 #include <linux/highmem.h>
  20 #include <linux/mm.h>
  21 #include <linux/module.h>
  22 #include <linux/pci.h>
  23 #include <linux/string.h>
  24 #include <linux/types.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/io.h>
  27
  28 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
  29                     enum dma_data_direction dir)
  30 {
  31         switch (dir) {
  32         case DMA_BIDIRECTIONAL:
  33                 __flush_invalidate_dcache_range((unsigned long)vaddr, size);
  34                 break;
  35
  36         case DMA_FROM_DEVICE:
  37                 __invalidate_dcache_range((unsigned long)vaddr, size);
  38                 break;
  39
  40         case DMA_TO_DEVICE:
  41                 __flush_dcache_range((unsigned long)vaddr, size);
  42                 break;
  43
  44         case DMA_NONE:
  45                 BUG();
  46                 break;
  47         }
  48 }
  49 EXPORT_SYMBOL(dma_cache_sync);
  50
  51 static void do_cache_op(dma_addr_t dma_handle, size_t size,
  52                         void (*fn)(unsigned long, unsigned long))
  53 {
  54         unsigned long off = dma_handle & (PAGE_SIZE - 1);
  55         unsigned long pfn = PFN_DOWN(dma_handle);
  56         struct page *page = pfn_to_page(pfn);
  57
  58         if (!PageHighMem(page))
  59                 fn((unsigned long)bus_to_virt(dma_handle), size);
  60         else
  61                 while (size > 0) {
  62                         size_t sz = min_t(size_t, size, PAGE_SIZE - off);
  63                         void *vaddr = kmap_atomic(page);
  64
  65                         fn((unsigned long)vaddr + off, sz);
  66                         kunmap_atomic(vaddr);
  67                         off = 0;
  68                         ++page;
  69                         size -= sz;
  70                 }
  71 }
  72
  73 static void xtensa_sync_single_for_cpu(struct device *dev,
  74                                        dma_addr_t dma_handle, size_t size,
  75                                        enum dma_data_direction dir)
  76 {
  77         switch (dir) {
  78         case DMA_BIDIRECTIONAL:
  79         case DMA_FROM_DEVICE:
  80                 do_cache_op(dma_handle, size, __invalidate_dcache_range);
  81                 break;
  82
  83         case DMA_NONE:
  84                 BUG();
  85                 break;
  86
  87         default:
  88                 break;
  89         }
  90 }
  91
  92 static void xtensa_sync_single_for_device(struct device *dev,
  93                                           dma_addr_t dma_handle, size_t size,
  94                                           enum dma_data_direction dir)
  95 {
  96         switch (dir) {
  97         case DMA_BIDIRECTIONAL:
  98         case DMA_TO_DEVICE:
  99                 if (XCHAL_DCACHE_IS_WRITEBACK)
 100                         do_cache_op(dma_handle, size, __flush_dcache_range);
 101                 break;
 102
 103         case DMA_NONE:
 104                 BUG();
 105                 break;
 106
 107         default:
 108                 break;
 109         }
 110 }
 111
 112 static void xtensa_sync_sg_for_cpu(struct device *dev,
 113                                    struct scatterlist *sg, int nents,
 114                                    enum dma_data_direction dir)
 115 {
 116         struct scatterlist *s;
 117         int i;
 118
 119         for_each_sg(sg, s, nents, i) {
 120                 xtensa_sync_single_for_cpu(dev, sg_dma_address(s),
 121                                            sg_dma_len(s), dir);
 122         }
 123 }
 124
 125 static void xtensa_sync_sg_for_device(struct device *dev,
 126                                       struct scatterlist *sg, int nents,
 127                                       enum dma_data_direction dir)
 128 {
 129         struct scatterlist *s;
 130         int i;
 131
 132         for_each_sg(sg, s, nents, i) {
 133                 xtensa_sync_single_for_device(dev, sg_dma_address(s),
 134                                               sg_dma_len(s), dir);
 135         }
 136 }
 137
 138 /*
 139  * Note: We assume that the full memory space is always mapped to 'kseg'
 140  *       Otherwise we have to use page attributes (not implemented).
 141  */
 142
 143 static void *xtensa_dma_alloc(struct device *dev, size_t size,
 144                               dma_addr_t *handle, gfp_t flag,
 145                               unsigned long attrs)
 146 {
 147         unsigned long ret;
 148         unsigned long uncached = 0;
 149
 150         /* ignore region speicifiers */
 151
 152         flag &= ~(__GFP_DMA | __GFP_HIGHMEM);
 153
 154         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
 155                 flag |= GFP_DMA;
 156         ret = (unsigned long)__get_free_pages(flag, get_order(size));
 157
 158         if (ret == 0)
 159                 return NULL;
 160
 161         /* We currently don't support coherent memory outside KSEG */
 162
 163         BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
 164                ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 165
 166         uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
 167         *handle = virt_to_bus((void *)ret);
 168         __invalidate_dcache_range(ret, size);
 169
 170         return (void *)uncached;
 171 }
 172
 173 static void xtensa_dma_free(struct device *hwdev, size_t size, void *vaddr,
 174                             dma_addr_t dma_handle, unsigned long attrs)
 175 {
 176         unsigned long addr = (unsigned long)vaddr +
 177                 XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
 178
 179         BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
 180                addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 181
 182         free_pages(addr, get_order(size));
 183 }
 184
 185 static dma_addr_t xtensa_map_page(struct device *dev, struct page *page,
 186                                   unsigned long offset, size_t size,
 187                                   enum dma_data_direction dir,
 188                                   unsigned long attrs)
 189 {
 190         dma_addr_t dma_handle = page_to_phys(page) + offset;
 191
 192         xtensa_sync_single_for_device(dev, dma_handle, size, dir);
 193         return dma_handle;
 194 }
 195
 196 static void xtensa_unmap_page(struct device *dev, dma_addr_t dma_handle,
 197                               size_t size, enum dma_data_direction dir,
 198                               unsigned long attrs)
 199 {
 200         xtensa_sync_single_for_cpu(dev, dma_handle, size, dir);
 201 }
 202
 203 static int xtensa_map_sg(struct device *dev, struct scatterlist *sg,
 204                          int nents, enum dma_data_direction dir,
 205                          unsigned long attrs)
 206 {
 207         struct scatterlist *s;
 208         int i;
 209
 210         for_each_sg(sg, s, nents, i) {
 211                 s->dma_address = xtensa_map_page(dev, sg_page(s), s->offset,
 212                                                  s->length, dir, attrs);
 213         }
 214         return nents;
 215 }
 216
 217 static void xtensa_unmap_sg(struct device *dev,
 218                             struct scatterlist *sg, int nents,
 219                             enum dma_data_direction dir,
 220                             unsigned long attrs)
 221 {
 222         struct scatterlist *s;
 223         int i;
 224
 225         for_each_sg(sg, s, nents, i) {
 226                 xtensa_unmap_page(dev, sg_dma_address(s),
 227                                   sg_dma_len(s), dir, attrs);
 228         }
 229 }
 230
 231 int xtensa_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 232 {
 233         return 0;
 234 }
 235
 236 struct dma_map_ops xtensa_dma_map_ops = {
 237         .alloc = xtensa_dma_alloc,
 238         .free = xtensa_dma_free,
 239         .map_page = xtensa_map_page,
 240         .unmap_page = xtensa_unmap_page,
 241         .map_sg = xtensa_map_sg,
 242         .unmap_sg = xtensa_unmap_sg,
 243         .sync_single_for_cpu = xtensa_sync_single_for_cpu,
 244         .sync_single_for_device = xtensa_sync_single_for_device,
 245         .sync_sg_for_cpu = xtensa_sync_sg_for_cpu,
 246         .sync_sg_for_device = xtensa_sync_sg_for_device,
 247         .mapping_error = xtensa_dma_mapping_error,
 248 };
 249 EXPORT_SYMBOL(xtensa_dma_map_ops);
 250
 251 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 252
 253 static int __init xtensa_dma_init(void)
 254 {
 255         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 256         return 0;
 257 }
 258 fs_initcall(xtensa_dma_init);