mirror of https://gitee.com/openkylin/linux.git
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Carsten Langgaard, carstenl@mips.com
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* Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
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*
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* Setting up the clock on the MIPS boards.
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*/
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#include <linux/init.h>
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#include <linux/kernel_stat.h>
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#include <linux/ptrace.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/mc146818rtc.h>
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#include <linux/irq.h>
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#include <linux/timex.h>
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#include <asm/mipsregs.h>
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#include <asm/time.h>
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#include <asm/mach-rc32434/rc32434.h>
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extern unsigned int idt_cpu_freq;
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/*
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* Figure out the r4k offset, the amount to increment the compare
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* register for each time tick. There is no RTC available.
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*
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* The RC32434 counts at half the CPU *core* speed.
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*/
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static unsigned long __init cal_r4koff(void)
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{
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mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2;
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return mips_hpt_frequency / HZ;
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}
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void __init plat_time_init(void)
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{
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unsigned int est_freq;
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unsigned long flags, r4k_offset;
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local_irq_save(flags);
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printk(KERN_INFO "calculating r4koff... ");
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r4k_offset = cal_r4koff();
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printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset);
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est_freq = 2 * r4k_offset * HZ;
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est_freq += 5000; /* round */
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est_freq -= est_freq % 10000;
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printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000,
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(est_freq % 1000000) * 100 / 1000000);
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local_irq_restore(flags);
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}
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