xref: /OK3568_Linux_fs/kernel/arch/mips/cobalt/time.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  *  Cobalt time initialization.
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  *  Copyright (C) 2007  Yoichi Yuasa <yuasa@linux-mips.org>
6*4882a593Smuzhiyun  */
7*4882a593Smuzhiyun #include <linux/i8253.h>
8*4882a593Smuzhiyun #include <linux/init.h>
9*4882a593Smuzhiyun 
10*4882a593Smuzhiyun #include <asm/gt64120.h>
11*4882a593Smuzhiyun #include <asm/time.h>
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun #define GT641XX_BASE_CLOCK	50000000	/* 50MHz */
14*4882a593Smuzhiyun 
plat_time_init(void)15*4882a593Smuzhiyun void __init plat_time_init(void)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun 	u32 start, end;
18*4882a593Smuzhiyun 	int i = HZ / 10;
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun 	setup_pit_timer();
21*4882a593Smuzhiyun 
22*4882a593Smuzhiyun 	gt641xx_set_base_clock(GT641XX_BASE_CLOCK);
23*4882a593Smuzhiyun 
24*4882a593Smuzhiyun 	/*
25*4882a593Smuzhiyun 	 * MIPS counter frequency is measured during a 100msec interval
26*4882a593Smuzhiyun 	 * using GT64111 timer0.
27*4882a593Smuzhiyun 	 */
28*4882a593Smuzhiyun 	while (!gt641xx_timer0_state())
29*4882a593Smuzhiyun 		;
30*4882a593Smuzhiyun 
31*4882a593Smuzhiyun 	start = read_c0_count();
32*4882a593Smuzhiyun 
33*4882a593Smuzhiyun 	while (i--)
34*4882a593Smuzhiyun 		while (!gt641xx_timer0_state())
35*4882a593Smuzhiyun 			;
36*4882a593Smuzhiyun 
37*4882a593Smuzhiyun 	end = read_c0_count();
38*4882a593Smuzhiyun 
39*4882a593Smuzhiyun 	mips_hpt_frequency = (end - start) * 10;
40*4882a593Smuzhiyun 	printk(KERN_INFO "MIPS counter frequency %dHz\n", mips_hpt_frequency);
41*4882a593Smuzhiyun }
42