pci-dma.c

   1 /* pci-dma.c: Dynamic DMA mapping support for the FRV CPUs that have MMUs
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/list.h>
  15 #include <linux/pci.h>
  16 #include <linux/export.h>
  17 #include <linux/highmem.h>
  18 #include <linux/scatterlist.h>
  19 #include <asm/io.h>
  20
  21 static void *frv_dma_alloc(struct device *hwdev, size_t size,
  22                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
  23 {
  24         void *ret;
  25
  26         ret = consistent_alloc(gfp, size, dma_handle);
  27         if (ret)
  28                 memset(ret, 0, size);
  29
  30         return ret;
  31 }
  32
  33 static void frv_dma_free(struct device *hwdev, size_t size, void *vaddr,
  34                 dma_addr_t dma_handle, unsigned long attrs)
  35 {
  36         consistent_free(vaddr);
  37 }
  38
  39 static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
  40                 int nents, enum dma_data_direction direction,
  41                 unsigned long attrs)
  42 {
  43         unsigned long dampr2;
  44         void *vaddr;
  45         int i;
  46         struct scatterlist *sg;
  47
  48         BUG_ON(direction == DMA_NONE);
  49
  50         dampr2 = __get_DAMPR(2);
  51
  52         for_each_sg(sglist, sg, nents, i) {
  53                 vaddr = kmap_atomic_primary(sg_page(sg));
  54
  55                 frv_dcache_writeback((unsigned long) vaddr,
  56                                      (unsigned long) vaddr + PAGE_SIZE);
  57
  58         }
  59
  60         kunmap_atomic_primary(vaddr);
  61         if (dampr2) {
  62                 __set_DAMPR(2, dampr2);
  63                 __set_IAMPR(2, dampr2);
  64         }
  65
  66         return nents;
  67 }
  68
  69 static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
  70                 unsigned long offset, size_t size,
  71                 enum dma_data_direction direction, unsigned long attrs)
  72 {
  73         flush_dcache_page(page);
  74         return (dma_addr_t) page_to_phys(page) + offset;
  75 }
  76
  77 static void frv_dma_sync_single_for_device(struct device *dev,
  78                 dma_addr_t dma_handle, size_t size,
  79                 enum dma_data_direction direction)
  80 {
  81         flush_write_buffers();
  82 }
  83
  84 static void frv_dma_sync_sg_for_device(struct device *dev,
  85                 struct scatterlist *sg, int nelems,
  86                 enum dma_data_direction direction)
  87 {
  88         flush_write_buffers();
  89 }
  90
  91
  92 static int frv_dma_supported(struct device *dev, u64 mask)
  93 {
  94         /*
  95          * we fall back to GFP_DMA when the mask isn't all 1s,
  96          * so we can't guarantee allocations that must be
  97          * within a tighter range than GFP_DMA..
  98          */
  99         if (mask < 0x00ffffff)
 100                 return 0;
 101         return 1;
 102 }
 103
 104 struct dma_map_ops frv_dma_ops = {
 105         .alloc                  = frv_dma_alloc,
 106         .free                   = frv_dma_free,
 107         .map_page               = frv_dma_map_page,
 108         .map_sg                 = frv_dma_map_sg,
 109         .sync_single_for_device = frv_dma_sync_single_for_device,
 110         .sync_sg_for_device     = frv_dma_sync_sg_for_device,
 111         .dma_supported          = frv_dma_supported,
 112 };
 113 EXPORT_SYMBOL(frv_dma_ops);