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@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
  28struct dma_alloc_record {
  29        struct list_head        list;
  30        unsigned long           ofs;
  31        unsigned long           len;
  32};
  33
  34static DEFINE_SPINLOCK(dma_alloc_lock);
  35static LIST_HEAD(dma_alloc_list);
  36
  37void *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
  87EXPORT_SYMBOL(dma_alloc_coherent);
  88
  89void 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
 108EXPORT_SYMBOL(dma_free_coherent);
 109
 110dma_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
 120EXPORT_SYMBOL(dma_map_single);
 121
 122int 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
 136EXPORT_SYMBOL(dma_map_sg);
 137
 138dma_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
 146EXPORT_SYMBOL(dma_map_page);
 147