1 | // SPDX-License-Identifier: GPL-2.0-only |
---|---|
2 | /* |
3 | * Carsten Langgaard, carstenl@mips.com |
4 | * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. |
5 | * |
6 | * Setting up the clock on the MIPS boards. |
7 | */ |
8 | |
9 | #include <linux/init.h> |
10 | #include <linux/kernel_stat.h> |
11 | #include <linux/ptrace.h> |
12 | #include <linux/sched.h> |
13 | #include <linux/spinlock.h> |
14 | #include <linux/mc146818rtc.h> |
15 | #include <linux/irq.h> |
16 | #include <linux/timex.h> |
17 | |
18 | #include <asm/mipsregs.h> |
19 | #include <asm/time.h> |
20 | #include <asm/mach-rc32434/rc32434.h> |
21 | |
22 | extern unsigned int idt_cpu_freq; |
23 | |
24 | /* |
25 | * Figure out the r4k offset, the amount to increment the compare |
26 | * register for each time tick. There is no RTC available. |
27 | * |
28 | * The RC32434 counts at half the CPU *core* speed. |
29 | */ |
30 | static unsigned long __init cal_r4koff(void) |
31 | { |
32 | mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2; |
33 | |
34 | return mips_hpt_frequency / HZ; |
35 | } |
36 | |
37 | void __init plat_time_init(void) |
38 | { |
39 | unsigned int est_freq; |
40 | unsigned long flags, r4k_offset; |
41 | |
42 | local_irq_save(flags); |
43 | |
44 | printk(KERN_INFO "calculating r4koff... "); |
45 | r4k_offset = cal_r4koff(); |
46 | printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset); |
47 | |
48 | est_freq = 2 * r4k_offset * HZ; |
49 | est_freq += 5000; /* round */ |
50 | est_freq -= est_freq % 10000; |
51 | printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000, |
52 | (est_freq % 1000000) * 100 / 1000000); |
53 | local_irq_restore(flags); |
54 | } |
55 |