summaryrefslogtreecommitdiff
path: root/arch/mn10300/mm/dma-alloc.c
blob: 86108d2496b35fa3727a6c9625b792fa47a21e90 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/* MN10300 Dynamic DMA mapping support
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Derived from: arch/i386/kernel/pci-dma.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <asm/io.h>

static unsigned long pci_sram_allocated = 0xbc000000;

static void *mn10300_dma_alloc(struct device *dev, size_t size,
		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
	unsigned long addr;
	void *ret;

	pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
		 dev ? dev_name(dev) : "?", size, gfp);

	if (0xbe000000 - pci_sram_allocated >= size) {
		size = (size + 255) & ~255;
		addr = pci_sram_allocated;
		pci_sram_allocated += size;
		ret = (void *) addr;
		goto done;
	}

	/* ignore region specifiers */
	gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);

	if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
		gfp |= GFP_DMA;

	addr = __get_free_pages(gfp, get_order(size));
	if (!addr)
		return NULL;

	/* map the coherent memory through the uncached memory window */
	ret = (void *) (addr | 0x20000000);

	/* fill the memory with obvious rubbish */
	memset((void *) addr, 0xfb, size);

	/* write back and evict all cache lines covering this region */
	mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);

done:
	*dma_handle = virt_to_bus((void *) addr);
	printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
	return ret;
}

static void mn10300_dma_free(struct device *dev, size_t size, void *vaddr,
		dma_addr_t dma_handle, unsigned long attrs)
{
	unsigned long addr = (unsigned long) vaddr & ~0x20000000;

	if (addr >= 0x9c000000)
		return;

	free_pages(addr, get_order(size));
}

static int mn10300_dma_map_sg(struct device *dev, struct scatterlist *sglist,
		int nents, enum dma_data_direction direction,
		unsigned long attrs)
{
	struct scatterlist *sg;
	int i;

	for_each_sg(sglist, sg, nents, i) {
		BUG_ON(!sg_page(sg));

		sg->dma_address = sg_phys(sg);
	}

	mn10300_dcache_flush_inv();
	return nents;
}

static dma_addr_t mn10300_dma_map_page(struct device *dev, struct page *page,
		unsigned long offset, size_t size,
		enum dma_data_direction direction, unsigned long attrs)
{
	return page_to_bus(page) + offset;
}

static void mn10300_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,
				size_t size, enum dma_data_direction direction)
{
	mn10300_dcache_flush_inv();
}

static void mn10300_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
			    int nelems, enum dma_data_direction direction)
{
	mn10300_dcache_flush_inv();
}

static int mn10300_dma_supported(struct device *dev, u64 mask)
{
	/*
	 * we fall back to GFP_DMA when the mask isn't all 1s, so we can't
	 * guarantee allocations that must be within a tighter range than
	 * GFP_DMA
	 */
	if (mask < 0x00ffffff)
		return 0;
	return 1;
}

const struct dma_map_ops mn10300_dma_ops = {
	.alloc			= mn10300_dma_alloc,
	.free			= mn10300_dma_free,
	.map_page		= mn10300_dma_map_page,
	.map_sg			= mn10300_dma_map_sg,
	.sync_single_for_device	= mn10300_dma_sync_single_for_device,
	.sync_sg_for_device	= mn10300_dma_sync_sg_for_device,
};