blob: aab0fa8ea28386fb6d3275da63a0b08440ac86fe (
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
|
/*
* Linux DMA channel management.
* Copyright (C) 1995 Shantanu Goel.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#define MACH_INCLUDE
#include <linux/errno.h>
#include <asm/dma.h>
/*
* Bitmap of allocated/free DMA channels.
*/
static int dma_busy = 0x10;
/*
* Allocate a DMA channel.
*/
int
request_dma(unsigned int drq, const char *name)
{
if (drq > 7)
panic("request_dma: bad DRQ number");
if (dma_busy & (1 << drq))
return (-LINUX_EBUSY);
dma_busy |= 1 << drq;
return (0);
}
/*
* Free a DMA channel.
*/
void
free_dma(unsigned int drq)
{
if (drq > 7)
panic("free_dma: bad DRQ number");
dma_busy &= ~(1 << drq);
}
|
