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mmtimer.h
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1 /*
2  * Intel Multimedia Timer device interface
3  *
4  * This file is subject to the terms and conditions of the GNU General Public
5  * License. See the file "COPYING" in the main directory of this archive
6  * for more details.
7  *
8  * Copyright (c) 2001-2004 Silicon Graphics, Inc. All rights reserved.
9  *
10  * This file should define an interface compatible with the IA-PC Multimedia
11  * Timers Draft Specification (rev. 0.97) from Intel. Note that some
12  * hardware may not be able to safely export its registers to userspace,
13  * so the ioctl interface should support all necessary functionality.
14  *
15  * 11/01/01 - jbarnes - initial revision
16  * 9/10/04 - Christoph Lameter - remove interrupt support
17  * 9/17/04 - jbarnes - remove test program, move some #defines to the driver
18  */
19 
20 #ifndef _LINUX_MMTIMER_H
21 #define _LINUX_MMTIMER_H
22 
23 /*
24  * Breakdown of the ioctl's available. An 'optional' next to the command
25  * indicates that supporting this command is optional, while 'required'
26  * commands must be implemented if conformance is desired.
27  *
28  * MMTIMER_GETOFFSET - optional
29  * Should return the offset (relative to the start of the page where the
30  * registers are mapped) for the counter in question.
31  *
32  * MMTIMER_GETRES - required
33  * The resolution of the clock in femto (10^-15) seconds
34  *
35  * MMTIMER_GETFREQ - required
36  * Frequency of the clock in Hz
37  *
38  * MMTIMER_GETBITS - required
39  * Number of bits in the clock's counter
40  *
41  * MMTIMER_MMAPAVAIL - required
42  * Returns nonzero if the registers can be mmap'd into userspace, 0 otherwise
43  *
44  * MMTIMER_GETCOUNTER - required
45  * Gets the current value in the counter
46  */
47 #define MMTIMER_IOCTL_BASE 'm'
48 
49 #define MMTIMER_GETOFFSET _IO(MMTIMER_IOCTL_BASE, 0)
50 #define MMTIMER_GETRES _IOR(MMTIMER_IOCTL_BASE, 1, unsigned long)
51 #define MMTIMER_GETFREQ _IOR(MMTIMER_IOCTL_BASE, 2, unsigned long)
52 #define MMTIMER_GETBITS _IO(MMTIMER_IOCTL_BASE, 4)
53 #define MMTIMER_MMAPAVAIL _IO(MMTIMER_IOCTL_BASE, 6)
54 #define MMTIMER_GETCOUNTER _IOR(MMTIMER_IOCTL_BASE, 9, unsigned long)
55 
56 #endif /* _LINUX_MMTIMER_H */