67 строки
1.9 KiB
C
67 строки
1.9 KiB
C
/*
|
|
* Carsten Langgaard, carstenl@mips.com
|
|
* Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
|
|
*
|
|
* This program is free software; you can distribute it and/or modify it
|
|
* under the terms of the GNU General Public License (Version 2) as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
|
|
*
|
|
* Setting up the clock on the MIPS boards.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/mc146818rtc.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/timex.h>
|
|
|
|
#include <asm/mipsregs.h>
|
|
#include <asm/time.h>
|
|
#include <asm/mach-rc32434/rc32434.h>
|
|
|
|
extern unsigned int idt_cpu_freq;
|
|
|
|
/*
|
|
* Figure out the r4k offset, the amount to increment the compare
|
|
* register for each time tick. There is no RTC available.
|
|
*
|
|
* The RC32434 counts at half the CPU *core* speed.
|
|
*/
|
|
static unsigned long __init cal_r4koff(void)
|
|
{
|
|
mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2;
|
|
|
|
return mips_hpt_frequency / HZ;
|
|
}
|
|
|
|
void __init plat_time_init(void)
|
|
{
|
|
unsigned int est_freq;
|
|
unsigned long flags, r4k_offset;
|
|
|
|
local_irq_save(flags);
|
|
|
|
printk(KERN_INFO "calculating r4koff... ");
|
|
r4k_offset = cal_r4koff();
|
|
printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset);
|
|
|
|
est_freq = 2 * r4k_offset * HZ;
|
|
est_freq += 5000; /* round */
|
|
est_freq -= est_freq % 10000;
|
|
printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000,
|
|
(est_freq % 1000000) * 100 / 1000000);
|
|
local_irq_restore(flags);
|
|
}
|