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 void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
  38 {
  39         struct dma_alloc_record *new;
  40         struct list_head *this = &dma_alloc_list;
  41         unsigned long flags;
  42         unsigned long start = DMA_SRAM_START;
  43         unsigned long end;
  44
  45         if (!DMA_SRAM_START) {
  46                 printk("%s called without any DMA area reserved!\n", __func__);
  47                 return NULL;
  48         }
  49
  50         new = kmalloc(sizeof (*new), GFP_ATOMIC);
  51         if (!new)
  52                 return NULL;
  53
  54         /* Round up to a reasonable alignment */
  55         new->len = (size + 31) & ~31;
  56
  57         spin_lock_irqsave(&dma_alloc_lock, flags);
  58
  59         list_for_each (this, &dma_alloc_list) {
  60                 struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
  61                 end = this_r->ofs;
  62
  63                 if (end - start >= size)
  64                         goto gotone;
  65
  66                 start = this_r->ofs + this_r->len;
  67         }
  68         /* Reached end of list. */
  69         end = DMA_SRAM_END;
  70         this = &dma_alloc_list;
  71
  72         if (end - start >= size) {
  73         gotone:
  74                 new->ofs = start;
  75                 list_add_tail(&new->list, this);
  76                 spin_unlock_irqrestore(&dma_alloc_lock, flags);
  77
  78                 *dma_handle = start;
  79                 return (void *)start;
  80         }
  81
  82         kfree(new);
  83         spin_unlock_irqrestore(&dma_alloc_lock, flags);
  84         return NULL;
  85 }
  86
  87 EXPORT_SYMBOL(dma_alloc_coherent);
  88
  89 void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
  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 EXPORT_SYMBOL(dma_free_coherent);
 109
 110 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
 111                           enum dma_data_direction direction)
 112 {
 113         BUG_ON(direction == DMA_NONE);
 114
 115         frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
 116
 117         return virt_to_bus(ptr);
 118 }
 119
 120 EXPORT_SYMBOL(dma_map_single);
 121
 122 int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 123                enum dma_data_direction direction)
 124 {
 125         int i;
 126
 127         for (i=0; i<nents; i++)
 128                 frv_cache_wback_inv(sg_dma_address(&sg[i]),
 129                                     sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
 130
 131         BUG_ON(direction == DMA_NONE);
 132
 133         return nents;
 134 }
 135
 136 EXPORT_SYMBOL(dma_map_sg);
 137
 138 dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
 139                         size_t size, enum dma_data_direction direction)
 140 {
 141         BUG_ON(direction == DMA_NONE);
 142         flush_dcache_page(page);
 143         return (dma_addr_t) page_to_phys(page) + offset;
 144 }
 145
 146 EXPORT_SYMBOL(dma_map_page);