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