diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-i386/mach-default/mach_timer.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-i386/mach-default/mach_timer.h')
-rw-r--r-- | include/asm-i386/mach-default/mach_timer.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/include/asm-i386/mach-default/mach_timer.h b/include/asm-i386/mach-default/mach_timer.h new file mode 100644 index 000000000000..4b9703bb0288 --- /dev/null +++ b/include/asm-i386/mach-default/mach_timer.h | |||
@@ -0,0 +1,48 @@ | |||
1 | /* | ||
2 | * include/asm-i386/mach-default/mach_timer.h | ||
3 | * | ||
4 | * Machine specific calibrate_tsc() for generic. | ||
5 | * Split out from timer_tsc.c by Osamu Tomita <tomita@cinet.co.jp> | ||
6 | */ | ||
7 | /* ------ Calibrate the TSC ------- | ||
8 | * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset(). | ||
9 | * Too much 64-bit arithmetic here to do this cleanly in C, and for | ||
10 | * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2) | ||
11 | * output busy loop as low as possible. We avoid reading the CTC registers | ||
12 | * directly because of the awkward 8-bit access mechanism of the 82C54 | ||
13 | * device. | ||
14 | */ | ||
15 | #ifndef _MACH_TIMER_H | ||
16 | #define _MACH_TIMER_H | ||
17 | |||
18 | #define CALIBRATE_LATCH (5 * LATCH) | ||
19 | |||
20 | static inline void mach_prepare_counter(void) | ||
21 | { | ||
22 | /* Set the Gate high, disable speaker */ | ||
23 | outb((inb(0x61) & ~0x02) | 0x01, 0x61); | ||
24 | |||
25 | /* | ||
26 | * Now let's take care of CTC channel 2 | ||
27 | * | ||
28 | * Set the Gate high, program CTC channel 2 for mode 0, | ||
29 | * (interrupt on terminal count mode), binary count, | ||
30 | * load 5 * LATCH count, (LSB and MSB) to begin countdown. | ||
31 | * | ||
32 | * Some devices need a delay here. | ||
33 | */ | ||
34 | outb(0xb0, 0x43); /* binary, mode 0, LSB/MSB, Ch 2 */ | ||
35 | outb_p(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */ | ||
36 | outb_p(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */ | ||
37 | } | ||
38 | |||
39 | static inline void mach_countup(unsigned long *count_p) | ||
40 | { | ||
41 | unsigned long count = 0; | ||
42 | do { | ||
43 | count++; | ||
44 | } while ((inb_p(0x61) & 0x20) == 0); | ||
45 | *count_p = count; | ||
46 | } | ||
47 | |||
48 | #endif /* !_MACH_TIMER_H */ | ||