| /* |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| * |
| * Copyright (C) 1998, 1999, 2003 by Ralf Baechle |
| */ |
| #ifndef _ASM_TIMEX_H |
| #define _ASM_TIMEX_H |
| |
| #include <asm/mipsregs.h> |
| |
| /* |
| * This is the frequency of the timer used for Linux's timer interrupt. |
| * The value should be defined as accurate as possible or under certain |
| * circumstances Linux timekeeping might become inaccurate or fail. |
| * |
| * For many system the exact clockrate of the timer isn't known but due to |
| * the way this value is used we can get away with a wrong value as long |
| * as this value is: |
| * |
| * - a multiple of HZ |
| * - a divisor of the actual rate |
| * |
| * 500000 is a good such cheat value. |
| * |
| * The obscure number 1193182 is the same as used by the original i8254 |
| * time in legacy PC hardware; the chip unfortunately also found in a |
| * bunch of MIPS systems. The last remaining user of the i8254 for the |
| * timer interrupt is the RM200; it's a very standard system so there is |
| * no reason to make this a separate architecture. |
| */ |
| |
| #include <timex.h> |
| |
| /* |
| * Standard way to access the cycle counter. |
| * Currently only used on SMP for scheduling. |
| * |
| * Only the low 32 bits are available as a continuously counting entity. |
| * But this only means we'll force a reschedule every 8 seconds or so, |
| * which isn't an evil thing. |
| * |
| * We know that all SMP capable CPUs have cycle counters. |
| */ |
| |
| typedef unsigned int cycles_t; |
| |
| static inline cycles_t get_cycles (void) |
| { |
| return read_c0_count(); |
| } |
| |
| #endif /* _ASM_TIMEX_H */ |