LXR linux/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
  27struct dma_alloc_record {
  28        struct list_head        list;
  29        unsigned long           ofs;
  30        unsigned long           len;
  31};
  32
  33static DEFINE_SPINLOCK(dma_alloc_lock);
  34static LIST_HEAD(dma_alloc_list);
  35
  36void *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
  86void 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 */
 112dma_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 */
 139int 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}
 153