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/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, gfp_t 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
 86EXPORT_SYMBOL(dma_alloc_coherent);
 87
 88void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
 89{
 90	struct dma_alloc_record *rec;
 91	unsigned long flags;
 92
 93	spin_lock_irqsave(&dma_alloc_lock, flags);
 94
 95	list_for_each_entry(rec, &dma_alloc_list, list) {
 96		if (rec->ofs == dma_handle) {
 97			list_del(&rec->list);
 98			kfree(rec);
 99			spin_unlock_irqrestore(&dma_alloc_lock, flags);
100			return;
101		}
102	}
103	spin_unlock_irqrestore(&dma_alloc_lock, flags);
104	BUG();
105}
106
107EXPORT_SYMBOL(dma_free_coherent);
108
109dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
110			  enum dma_data_direction direction)
111{
112	BUG_ON(direction == DMA_NONE);
113
114	frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
115
116	return virt_to_bus(ptr);
117}
118
119EXPORT_SYMBOL(dma_map_single);
120
121int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
122	       enum dma_data_direction direction)
123{
124	int i;
125
126	for (i=0; i<nents; i++)
127		frv_cache_wback_inv(sg_dma_address(&sg[i]),
128				    sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
129
130	BUG_ON(direction == DMA_NONE);
131
132	return nents;
133}
134
135EXPORT_SYMBOL(dma_map_sg);
136
137dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
138			size_t size, enum dma_data_direction direction)
139{
140	BUG_ON(direction == DMA_NONE);
141	flush_dcache_page(page);
142	return (dma_addr_t) page_to_phys(page) + offset;
143}
144
145EXPORT_SYMBOL(dma_map_page);