File: consistent.c

package info (click to toggle)
kernel-source-2.4.14 2.4.14-1
  • links: PTS
  • area: main
  • in suites: woody
  • size: 139,160 kB
  • ctags: 428,423
  • sloc: ansic: 2,435,554; asm: 141,119; makefile: 8,258; sh: 3,099; perl: 2,561; yacc: 1,177; cpp: 755; tcl: 577; lex: 352; awk: 251; lisp: 218; sed: 72
file content (159 lines) | stat: -rw-r--r-- 3,694 bytes parent folder | download | duplicates (8)
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
 *  linux/arch/arm/mm/consistent.c
 *
 *  Copyright (C) 2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Dynamic DMA mapping support.
 */
#include <linux/config.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/init.h>

#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>

/*
 * This allocates one page of cache-coherent memory space and returns
 * both the virtual and a "dma" address to that space.  It is not clear
 * whether this could be called from an interrupt context or not.  For
 * now, we expressly forbid it, especially as some of the stuff we do
 * here is not interrupt context safe.
 *
 * Note that this does *not* zero the allocated area!
 */
void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle)
{
	struct page *page, *end, *free;
	unsigned long order;
	void *ret, *virt;

	if (in_interrupt())
		BUG();

	size = PAGE_ALIGN(size);
	order = get_order(size);

	page = alloc_pages(gfp, order);
	if (!page)
		goto no_page;

	/*
	 * We could do with a page_to_phys and page_to_bus here.
	 */
	virt = page_address(page);
	*dma_handle = virt_to_bus(virt);
	ret = __ioremap(virt_to_phys(virt), size, 0);
	if (!ret)
		goto no_remap;

#if 0 /* ioremap_does_flush_cache_all */
	/*
	 * we need to ensure that there are no cachelines in use, or
	 * worse dirty in this area.  Really, we don't need to do
	 * this since __ioremap does a flush_cache_all() anyway. --rmk
	 */
	invalidate_dcache_range(virt, virt + size);
#endif

	/*
	 * free wasted pages.  We skip the first page since we know
	 * that it will have count = 1 and won't require freeing.
	 * We also mark the pages in use as reserved so that
	 * remap_page_range works.
	 */
	page = virt_to_page(virt);
	free = page + (size >> PAGE_SHIFT);
	end  = page + (1 << order);

	for (; page < end; page++) {
		set_page_count(page, 1);
		if (page >= free)
			__free_page(page);
		else
			SetPageReserved(page);
	}
	return ret;

no_remap:
	__free_pages(page, order);
no_page:
	return NULL;
}

void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size, dma_addr_t *handle)
{
	void *__ret;
	int __gfp = GFP_KERNEL;

#ifdef CONFIG_PCI
	if ((hwdev) == NULL ||
	    (hwdev)->dma_mask != 0xffffffff)
#endif
		__gfp |= GFP_DMA;

	__ret = consistent_alloc(__gfp, (size),
				 (handle));
	return __ret;
}

/*
 * free a page as defined by the above mapping.  We expressly forbid
 * calling this from interrupt context.
 */
void consistent_free(void *vaddr, size_t size, dma_addr_t handle)
{
	struct page *page, *end;
	void *virt;

	if (in_interrupt())
		BUG();

	virt = bus_to_virt(handle);

	/*
	 * More messing around with the MM internals.  This is
	 * sick, but then so is remap_page_range().
	 */
	size = PAGE_ALIGN(size);
	page = virt_to_page(virt);
	end = page + (size >> PAGE_SHIFT);

	for (; page < end; page++)
		ClearPageReserved(page);

	__iounmap(vaddr);
}

/*
 * make an area consistent.
 */
void consistent_sync(void *vaddr, size_t size, int direction)
{
	unsigned long start = (unsigned long)vaddr;
	unsigned long end   = start + size;

	switch (direction) {
	case PCI_DMA_NONE:
		BUG();
	case PCI_DMA_FROMDEVICE:	/* invalidate only */
		invalidate_dcache_range(start, end);
		break;
	case PCI_DMA_TODEVICE:		/* writeback only */
		clean_dcache_range(start, end);
		break;
	case PCI_DMA_BIDIRECTIONAL:	/* writeback and invalidate */
		flush_dcache_range(start, end);
		break;
	}
}