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
  37static void *frv_dma_alloc(struct device *hwdev, size_t size, dma_addr_t *dma_handle,
  38                gfp_t gfp, unsigned long 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
  88static void frv_dma_free(struct device *hwdev, size_t size, void *vaddr,
  89                dma_addr_t dma_handle, unsigned long 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
 108static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 109                int nents, enum dma_data_direction direction,
 110                unsigned long attrs)
 111{
 112        struct scatterlist *sg;
 113        int i;
 114
 115        BUG_ON(direction == DMA_NONE);
 116
 117        if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
 118                return nents;
 119
 120        for_each_sg(sglist, sg, nents, i) {
 121                frv_cache_wback_inv(sg_dma_address(sg),
 122                                    sg_dma_address(sg) + sg_dma_len(sg));
 123        }
 124
 125        return nents;
 126}
 127
 128static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
 129                unsigned long offset, size_t size,
 130                enum dma_data_direction direction, unsigned long attrs)
 131{
 132        BUG_ON(direction == DMA_NONE);
 133
 134        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 135                flush_dcache_page(page);
 136
 137        return (dma_addr_t) page_to_phys(page) + offset;
 138}
 139
 140static void frv_dma_sync_single_for_device(struct device *dev,
 141                dma_addr_t dma_handle, size_t size,
 142                enum dma_data_direction direction)
 143{
 144        flush_write_buffers();
 145}
 146
 147static void frv_dma_sync_sg_for_device(struct device *dev,
 148                struct scatterlist *sg, int nelems,
 149                enum dma_data_direction direction)
 150{
 151        flush_write_buffers();
 152}
 153
 154
 155static int frv_dma_supported(struct device *dev, u64 mask)
 156{
 157        /*
 158         * we fall back to GFP_DMA when the mask isn't all 1s,
 159         * so we can't guarantee allocations that must be
 160         * within a tighter range than GFP_DMA..
 161         */
 162        if (mask < 0x00ffffff)
 163                return 0;
 164        return 1;
 165}
 166
 167const struct dma_map_ops frv_dma_ops = {
 168        .alloc                  = frv_dma_alloc,
 169        .free                   = frv_dma_free,
 170        .map_page               = frv_dma_map_page,
 171        .map_sg                 = frv_dma_map_sg,
 172        .sync_single_for_device = frv_dma_sync_single_for_device,
 173        .sync_sg_for_device     = frv_dma_sync_sg_for_device,
 174        .dma_supported          = frv_dma_supported,
 175};
 176EXPORT_SYMBOL(frv_dma_ops);
 177