| Ralf Baechle | 73b4390 | 2008-07-16 16:12:25 +0100 | [diff] [blame^] | 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 | { |
| 52 | unsigned int est_freq, flags; |
| 53 | unsigned long r4k_offset; |
| 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 | } |