diff options
Diffstat (limited to 'arch/mips/rb532/time.c')
| -rw-r--r-- | arch/mips/rb532/time.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/mips/rb532/time.c b/arch/mips/rb532/time.c new file mode 100644 index 00000000000..db74edf8cef --- /dev/null +++ b/arch/mips/rb532/time.c @@ -0,0 +1,67 @@ +/* + * 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/debug.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, flags; + unsigned long 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); +} |