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authorRalf Baechle <ralf@linux-mips.org>2007-11-01 11:45:37 -0400
committerRalf Baechle <ralf@linux-mips.org>2007-11-02 12:13:48 -0400
commit72fc19ff51cc32fe85ddb085cb0622b7b97b2158 (patch)
tree784f9cdfba9a0c34ef994a9619de23e00c3479e5 /include/asm-mips/timex.h
parentc9294022af5022584756d67164e68dba0be9302b (diff)
[MIPS] Fix and cleanup the MIPS part of the (ab)use of CLOCK_TICK_RATE.
This is the clock rate of the i8253 PIT. A MIPS system may not have a PIT by the symbol is used all over the kernel including some APIs. So keeping it defined to the number for the PIT is the only sane thing for now. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'include/asm-mips/timex.h')
-rw-r--r--include/asm-mips/timex.h25
1 files changed, 5 insertions, 20 deletions
diff --git a/include/asm-mips/timex.h b/include/asm-mips/timex.h
index 87c68ae76ff8..5816ad1569d6 100644
--- a/include/asm-mips/timex.h
+++ b/include/asm-mips/timex.h
@@ -13,27 +13,12 @@
13#include <asm/mipsregs.h> 13#include <asm/mipsregs.h>
14 14
15/* 15/*
16 * This is the frequency of the timer used for Linux's timer interrupt. 16 * This is the clock rate of the i8253 PIT. A MIPS system may not have
17 * The value should be defined as accurate as possible or under certain 17 * a PIT by the symbol is used all over the kernel including some APIs.
18 * circumstances Linux timekeeping might become inaccurate or fail. 18 * So keeping it defined to the number for the PIT is the only sane thing
19 * 19 * for now.
20 * For many system the exact clockrate of the timer isn't known but due to
21 * the way this value is used we can get away with a wrong value as long
22 * as this value is:
23 *
24 * - a multiple of HZ
25 * - a divisor of the actual rate
26 *
27 * 500000 is a good such cheat value.
28 *
29 * The obscure number 1193182 is the same as used by the original i8254
30 * time in legacy PC hardware; the chip unfortunately also found in a
31 * bunch of MIPS systems. The last remaining user of the i8254 for the
32 * timer interrupt is the RM200; it's a very standard system so there is
33 * no reason to make this a separate architecture.
34 */ 20 */
35 21#define CLOCK_TICK_RATE 1193182
36#include <timex.h>
37 22
38/* 23/*
39 * Standard way to access the cycle counter. 24 * Standard way to access the cycle counter.