1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Carsten Langgaard, carstenl@mips.com 4*4882a593Smuzhiyun * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. 5*4882a593Smuzhiyun * 6*4882a593Smuzhiyun * Setting up the clock on the MIPS boards. 7*4882a593Smuzhiyun */ 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun #include <linux/init.h> 10*4882a593Smuzhiyun #include <linux/kernel_stat.h> 11*4882a593Smuzhiyun #include <linux/ptrace.h> 12*4882a593Smuzhiyun #include <linux/sched.h> 13*4882a593Smuzhiyun #include <linux/spinlock.h> 14*4882a593Smuzhiyun #include <linux/mc146818rtc.h> 15*4882a593Smuzhiyun #include <linux/irq.h> 16*4882a593Smuzhiyun #include <linux/timex.h> 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun #include <asm/mipsregs.h> 19*4882a593Smuzhiyun #include <asm/time.h> 20*4882a593Smuzhiyun #include <asm/mach-rc32434/rc32434.h> 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun extern unsigned int idt_cpu_freq; 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun /* 25*4882a593Smuzhiyun * Figure out the r4k offset, the amount to increment the compare 26*4882a593Smuzhiyun * register for each time tick. There is no RTC available. 27*4882a593Smuzhiyun * 28*4882a593Smuzhiyun * The RC32434 counts at half the CPU *core* speed. 29*4882a593Smuzhiyun */ cal_r4koff(void)30*4882a593Smuzhiyunstatic unsigned long __init cal_r4koff(void) 31*4882a593Smuzhiyun { 32*4882a593Smuzhiyun mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2; 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun return mips_hpt_frequency / HZ; 35*4882a593Smuzhiyun } 36*4882a593Smuzhiyun plat_time_init(void)37*4882a593Smuzhiyunvoid __init plat_time_init(void) 38*4882a593Smuzhiyun { 39*4882a593Smuzhiyun unsigned int est_freq; 40*4882a593Smuzhiyun unsigned long flags, r4k_offset; 41*4882a593Smuzhiyun 42*4882a593Smuzhiyun local_irq_save(flags); 43*4882a593Smuzhiyun 44*4882a593Smuzhiyun printk(KERN_INFO "calculating r4koff... "); 45*4882a593Smuzhiyun r4k_offset = cal_r4koff(); 46*4882a593Smuzhiyun printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset); 47*4882a593Smuzhiyun 48*4882a593Smuzhiyun est_freq = 2 * r4k_offset * HZ; 49*4882a593Smuzhiyun est_freq += 5000; /* round */ 50*4882a593Smuzhiyun est_freq -= est_freq % 10000; 51*4882a593Smuzhiyun printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000, 52*4882a593Smuzhiyun (est_freq % 1000000) * 100 / 1000000); 53*4882a593Smuzhiyun local_irq_restore(flags); 54*4882a593Smuzhiyun } 55