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 } 68