1/* 2 * time.c: MIPS CPU Count/Compare timer hookup 3 * 4 * Author: Mark.Zhan, <rongkai.zhan@windriver.com> 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file "COPYING" in the main directory of this archive 8 * for more details. 9 * 10 * Copyright (C) 1996, 1997, 2004 by Ralf Baechle (ralf@linux-mips.org) 11 * Copyright (C) 2006, Wind River System Inc. 12 */ 13#include <linux/init.h> 14#include <linux/interrupt.h> 15#include <linux/irq.h> 16 17#include <asm/gt64120.h> 18#include <asm/time.h> 19 20#define WRPPMC_CPU_CLK_FREQ 40000000 /* 40MHZ */ 21 22/* 23 * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect 24 * 25 * NOTE: We disable all GT64120 timers, and use MIPS processor internal 26 * timer as the source of kernel clock tick. 27 */ 28void __init plat_time_init(void) 29{ 30 /* Disable GT64120 timers */ 31 GT_WRITE(GT_TC_CONTROL_OFS, 0x00); 32 GT_WRITE(GT_TC0_OFS, 0x00); 33 GT_WRITE(GT_TC1_OFS, 0x00); 34 GT_WRITE(GT_TC2_OFS, 0x00); 35 GT_WRITE(GT_TC3_OFS, 0x00); 36 37 /* Use MIPS compare/count internal timer */ 38 mips_hpt_frequency = WRPPMC_CPU_CLK_FREQ; 39} 40