/* * time.c: MIPS CPU Count/Compare timer hookup * * Author: Mark.Zhan, <rongkai.zhan@windriver.com> * * 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) 1996, 1997, 2004 by Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 2006, Wind River System Inc. */ #include <linux/config.h> #include <linux/init.h> #include <linux/string.h> #include <linux/kernel.h> #include <linux/param.h> /* for HZ */ #include <linux/irq.h> #include <linux/timex.h> #include <linux/interrupt.h> #include <asm/reboot.h> #include <asm/time.h> #include <asm/io.h> #include <asm/bootinfo.h> #include <asm/gt64120.h> #define WRPPMC_CPU_CLK_FREQ 40000000 /* 40MHZ */ void __init wrppmc_timer_setup(struct irqaction *irq) { /* Install ISR for timer interrupt */ setup_irq(WRPPMC_MIPS_TIMER_IRQ, irq); /* to generate the first timer interrupt */ write_c0_compare(mips_hpt_frequency/HZ); write_c0_count(0); } /* * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect * * NOTE: We disable all GT64120 timers, and use MIPS processor internal * timer as the source of kernel clock tick. */ void __init wrppmc_time_init(void) { /* Disable GT64120 timers */ GT_WRITE(GT_TC_CONTROL_OFS, 0x00); GT_WRITE(GT_TC0_OFS, 0x00); GT_WRITE(GT_TC1_OFS, 0x00); GT_WRITE(GT_TC2_OFS, 0x00); GT_WRITE(GT_TC3_OFS, 0x00); /* Use MIPS compare/count internal timer */ mips_hpt_frequency = WRPPMC_CPU_CLK_FREQ; }