arch/frv/mb93090-mb00/pci-dma-nommu.c

   1 /* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Woodhouse (dwmw2@infradead.org)
   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/slab.h>
  14 #include <linux/export.h>
  15 #include <linux/dma-mapping.h>
  16 #include <linux/list.h>
  17 #include <linux/pci.h>
  18 #include <asm/io.h>
  19
  20 #if 1
  21 #define DMA_SRAM_START  dma_coherent_mem_start
  22 #define DMA_SRAM_END    dma_coherent_mem_end
  23 #else // Use video RAM on Matrox
  24 #define DMA_SRAM_START  0xe8900000
  25 #define DMA_SRAM_END    0xe8a00000
  26 #endif
  27
  28 struct dma_alloc_record {
  29         struct list_head        list;
  30         unsigned long           ofs;
  31         unsigned long           len;
  32 };
  33
  34 static DEFINE_SPINLOCK(dma_alloc_lock);
  35 static LIST_HEAD(dma_alloc_list);
  36
  37 static void *frv_dma_alloc(struct device *hwdev, size_t size, dma_addr_t *dma_handle,
  38                 gfp_t gfp, struct dma_attrs *attrs)
  39 {
  40         struct dma_alloc_record *new;
  41         struct list_head *this = &dma_alloc_list;
  42         unsigned long flags;
  43         unsigned long start = DMA_SRAM_START;
  44         unsigned long end;
  45
  46         if (!DMA_SRAM_START) {
  47                 printk("%s called without any DMA area reserved!\n", __func__);
  48                 return NULL;
  49         }
  50
  51         new = kmalloc(sizeof (*new), GFP_ATOMIC);
  52         if (!new)
  53                 return NULL;
  54
  55         /* Round up to a reasonable alignment */
  56         new->len = (size + 31) & ~31;
  57
  58         spin_lock_irqsave(&dma_alloc_lock, flags);
  59
  60         list_for_each (this, &dma_alloc_list) {
  61                 struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
  62                 end = this_r->ofs;
  63
  64                 if (end - start >= size)
  65                         goto gotone;
  66
  67                 start = this_r->ofs + this_r->len;
  68         }
  69         /* Reached end of list. */
  70         end = DMA_SRAM_END;
  71         this = &dma_alloc_list;
  72
  73         if (end - start >= size) {
  74         gotone:
  75                 new->ofs = start;
  76                 list_add_tail(&new->list, this);
  77                 spin_unlock_irqrestore(&dma_alloc_lock, flags);
  78
  79                 *dma_handle = start;
  80                 return (void *)start;
  81         }
  82
  83         kfree(new);
  84         spin_unlock_irqrestore(&dma_alloc_lock, flags);
  85         return NULL;
  86 }
  87
  88 static void frv_dma_free(struct device *hwdev, size_t size, void *vaddr,
  89                 dma_addr_t dma_handle, struct dma_attrs *attrs)
  90 {
  91         struct dma_alloc_record *rec;
  92         unsigned long flags;
  93
  94         spin_lock_irqsave(&dma_alloc_lock, flags);
  95
  96         list_for_each_entry(rec, &dma_alloc_list, list) {
  97                 if (rec->ofs == dma_handle) {
  98                         list_del(&rec->list);
  99                         kfree(rec);
 100                         spin_unlock_irqrestore(&dma_alloc_lock, flags);
 101                         return;
 102                 }
 103         }
 104         spin_unlock_irqrestore(&dma_alloc_lock, flags);
 105         BUG();
 106 }
 107
 108 static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 109                 int nents, enum dma_data_direction direction,
 110                 struct dma_attrs *attrs)
 111 {
 112         int i;
 113         struct scatterlist *sg;
 114
 115         for_each_sg(sglist, sg, nents, i) {
 116                 frv_cache_wback_inv(sg_dma_address(sg),
 117                                     sg_dma_address(sg) + sg_dma_len(sg));
 118         }
 119
 120         BUG_ON(direction == DMA_NONE);
 121
 122         return nents;
 123 }
 124
 125 static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
 126                 unsigned long offset, size_t size,
 127                 enum dma_data_direction direction, struct dma_attrs *attrs)
 128 {
 129         BUG_ON(direction == DMA_NONE);
 130         flush_dcache_page(page);
 131         return (dma_addr_t) page_to_phys(page) + offset;
 132 }
 133
 134 static void frv_dma_sync_single_for_device(struct device *dev,
 135                 dma_addr_t dma_handle, size_t size,
 136                 enum dma_data_direction direction)
 137 {
 138         flush_write_buffers();
 139 }
 140
 141 static void frv_dma_sync_sg_for_device(struct device *dev,
 142                 struct scatterlist *sg, int nelems,
 143                 enum dma_data_direction direction)
 144 {
 145         flush_write_buffers();
 146 }
 147
 148
 149 static int frv_dma_supported(struct device *dev, u64 mask)
 150 {
 151         /*
 152          * we fall back to GFP_DMA when the mask isn't all 1s,
 153          * so we can't guarantee allocations that must be
 154          * within a tighter range than GFP_DMA..
 155          */
 156         if (mask < 0x00ffffff)
 157                 return 0;
 158         return 1;
 159 }
 160
 161 struct dma_map_ops frv_dma_ops = {
 162         .alloc                  = frv_dma_alloc,
 163         .free                   = frv_dma_free,
 164         .map_page               = frv_dma_map_page,
 165         .map_sg                 = frv_dma_map_sg,
 166         .sync_single_for_device = frv_dma_sync_single_for_device,
 167         .sync_sg_for_device     = frv_dma_sync_sg_for_device,
 168         .dma_supported          = frv_dma_supported,
 169 };
 170 EXPORT_SYMBOL(frv_dma_ops);