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