/* * 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 #ifdef __KERNEL__ #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 /* __KERNEL__ */ #endif /* _ASM_TIMEX_H */