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 */
plat_time_init(void)28 void __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