2 * time.c: MIPS CPU Count/Compare timer hookup
4 * Author: Mark.Zhan, <rongkai.zhan@windriver.com>
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
10 * Copyright (C) 1996, 1997, 2004 by Ralf Baechle (ralf@linux-mips.org)
11 * Copyright (C) 2006, Wind River System Inc.
13 #include <linux/config.h>
14 #include <linux/init.h>
15 #include <linux/string.h>
16 #include <linux/kernel.h>
17 #include <linux/param.h> /* for HZ */
18 #include <linux/irq.h>
19 #include <linux/timex.h>
20 #include <linux/interrupt.h>
22 #include <asm/reboot.h>
25 #include <asm/bootinfo.h>
26 #include <asm/gt64120.h>
28 #define WRPPMC_CPU_CLK_FREQ 40000000 /* 40MHZ */
30 void __init wrppmc_timer_setup(struct irqaction *irq)
32 /* Install ISR for timer interrupt */
33 setup_irq(WRPPMC_MIPS_TIMER_IRQ, irq);
35 /* to generate the first timer interrupt */
36 write_c0_compare(mips_hpt_frequency/HZ);
41 * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect
43 * NOTE: We disable all GT64120 timers, and use MIPS processor internal
44 * timer as the source of kernel clock tick.
46 void __init wrppmc_time_init(void)
48 /* Disable GT64120 timers */
49 GT_WRITE(GT_TC_CONTROL_OFS, 0x00);
50 GT_WRITE(GT_TC0_OFS, 0x00);
51 GT_WRITE(GT_TC1_OFS, 0x00);
52 GT_WRITE(GT_TC2_OFS, 0x00);
53 GT_WRITE(GT_TC3_OFS, 0x00);
55 /* Use MIPS compare/count internal timer */
56 mips_hpt_frequency = WRPPMC_CPU_CLK_FREQ;