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@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/slab.h>
  14 #include <linux/dma-mapping.h>
  15 #include <linux/list.h>
  16 #include <linux/pci.h>
  17 #include <asm/io.h>
  18
  19 #if 1
  20 #define DMA_SRAM_START  dma_coherent_mem_start
  21 #define DMA_SRAM_END    dma_coherent_mem_end
  22 #else // Use video RAM on Matrox
  23 #define DMA_SRAM_START  0xe8900000
  24 #define DMA_SRAM_END    0xe8a00000
  25 #endif
  26
  27 struct dma_alloc_record {
  28         struct list_head        list;
  29         unsigned long           ofs;
  30         unsigned long           len;
  31 };
  32
  33 static DEFINE_SPINLOCK(dma_alloc_lock);
  34 static LIST_HEAD(dma_alloc_list);
  35
  36 void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, int gfp)
  37 {
  38         struct dma_alloc_record *new;
  39         struct list_head *this = &dma_alloc_list;
  40         unsigned long flags;
  41         unsigned long start = DMA_SRAM_START;
  42         unsigned long end;
  43
  44         if (!DMA_SRAM_START) {
  45                 printk("%s called without any DMA area reserved!\n", __func__);
  46                 return NULL;
  47         }
  48
  49         new = kmalloc(sizeof (*new), GFP_ATOMIC);
  50         if (!new)
  51                 return NULL;
  52
  53         /* Round up to a reasonable alignment */
  54         new->len = (size + 31) & ~31;
  55
  56         spin_lock_irqsave(&dma_alloc_lock, flags);
  57
  58         list_for_each (this, &dma_alloc_list) {
  59                 struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
  60                 end = this_r->ofs;
  61
  62                 if (end - start >= size)
  63                         goto gotone;
  64
  65                 start = this_r->ofs + this_r->len;
  66         }
  67         /* Reached end of list. */
  68         end = DMA_SRAM_END;
  69         this = &dma_alloc_list;
  70
  71         if (end - start >= size) {
  72         gotone:
  73                 new->ofs = start;
  74                 list_add_tail(&new->list, this);
  75                 spin_unlock_irqrestore(&dma_alloc_lock, flags);
  76
  77                 *dma_handle = start;
  78                 return (void *)start;
  79         }
  80
  81         kfree(new);
  82         spin_unlock_irqrestore(&dma_alloc_lock, flags);
  83         return NULL;
  84 }
  85
  86 void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
  87 {
  88         struct dma_alloc_record *rec;
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&dma_alloc_lock, flags);
  92
  93         list_for_each_entry(rec, &dma_alloc_list, list) {
  94                 if (rec->ofs == dma_handle) {
  95                         list_del(&rec->list);
  96                         kfree(rec);
  97                         spin_unlock_irqrestore(&dma_alloc_lock, flags);
  98                         return;
  99                 }
 100         }
 101         spin_unlock_irqrestore(&dma_alloc_lock, flags);
 102         BUG();
 103 }
 104
 105 /*
 106  * Map a single buffer of the indicated size for DMA in streaming mode.
 107  * The 32-bit bus address to use is returned.
 108  *
 109  * Once the device is given the dma address, the device owns this memory
 110  * until either pci_unmap_single or pci_dma_sync_single is performed.
 111  */
 112 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
 113                           enum dma_data_direction direction)
 114 {
 115         if (direction == DMA_NONE)
 116                 BUG();
 117
 118         frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
 119
 120         return virt_to_bus(ptr);
 121 }
 122
 123 /*
 124  * Map a set of buffers described by scatterlist in streaming
 125  * mode for DMA.  This is the scather-gather version of the
 126  * above pci_map_single interface.  Here the scatter gather list
 127  * elements are each tagged with the appropriate dma address
 128  * and length.  They are obtained via sg_dma_{address,length}(SG).
 129  *
 130  * NOTE: An implementation may be able to use a smaller number of
 131  *       DMA address/length pairs than there are SG table elements.
 132  *       (for example via virtual mapping capabilities)
 133  *       The routine returns the number of addr/length pairs actually
 134  *       used, at most nents.
 135  *
 136  * Device ownership issues as mentioned above for pci_map_single are
 137  * the same here.
 138  */
 139 int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 140                enum dma_data_direction direction)
 141 {
 142         int i;
 143
 144         for (i=0; i<nents; i++)
 145                 frv_cache_wback_inv(sg_dma_address(&sg[i]),
 146                                     sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
 147
 148         if (direction == DMA_NONE)
 149                 BUG();
 150
 151         return nents;
 152 }