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73b4390f RB |
1 | /* |
2 | * Carsten Langgaard, carstenl@mips.com | |
3 | * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. | |
4 | * | |
5 | * This program is free software; you can distribute it and/or modify it | |
6 | * under the terms of the GNU General Public License (Version 2) as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 | * for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along | |
15 | * with this program; if not, write to the Free Software Foundation, Inc., | |
16 | * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. | |
17 | * | |
18 | * Setting up the clock on the MIPS boards. | |
19 | */ | |
20 | ||
21 | #include <linux/init.h> | |
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/ptrace.h> | |
24 | #include <linux/sched.h> | |
25 | #include <linux/spinlock.h> | |
26 | #include <linux/mc146818rtc.h> | |
27 | #include <linux/irq.h> | |
28 | #include <linux/timex.h> | |
29 | ||
30 | #include <asm/mipsregs.h> | |
31 | #include <asm/debug.h> | |
32 | #include <asm/time.h> | |
33 | #include <asm/mach-rc32434/rc32434.h> | |
34 | ||
35 | extern unsigned int idt_cpu_freq; | |
36 | ||
37 | /* | |
38 | * Figure out the r4k offset, the amount to increment the compare | |
39 | * register for each time tick. There is no RTC available. | |
40 | * | |
41 | * The RC32434 counts at half the CPU *core* speed. | |
42 | */ | |
43 | static unsigned long __init cal_r4koff(void) | |
44 | { | |
45 | mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2; | |
46 | ||
47 | return mips_hpt_frequency / HZ; | |
48 | } | |
49 | ||
50 | void __init plat_time_init(void) | |
51 | { | |
8b32d6d0 AB |
52 | unsigned int est_freq; |
53 | unsigned long flags, r4k_offset; | |
73b4390f RB |
54 | |
55 | local_irq_save(flags); | |
56 | ||
57 | printk(KERN_INFO "calculating r4koff... "); | |
58 | r4k_offset = cal_r4koff(); | |
59 | printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset); | |
60 | ||
61 | est_freq = 2 * r4k_offset * HZ; | |
62 | est_freq += 5000; /* round */ | |
63 | est_freq -= est_freq % 10000; | |
64 | printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000, | |
65 | (est_freq % 1000000) * 100 / 1000000); | |
66 | local_irq_restore(flags); | |
67 | } |