diff options
Diffstat (limited to 'target/linux/rb532/files/arch/mips/rb500/time.c')
| -rw-r--r-- | target/linux/rb532/files/arch/mips/rb500/time.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/target/linux/rb532/files/arch/mips/rb500/time.c b/target/linux/rb532/files/arch/mips/rb500/time.c new file mode 100644 index 000000000..13320a6ca --- /dev/null +++ b/target/linux/rb532/files/arch/mips/rb500/time.c @@ -0,0 +1,94 @@ +/* +**************************************************************************** +* 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. +* +**************************************************************************** +* P. Sadik Oct 10, 2003 +* +* Started change log. +* mips_counter_frequency is now calculated at run time, based on idt_cpu_freq. +* Code cleanup +**************************************************************************** +*/ + +#include <linux/autoconf.h> +#include <linux/init.h> +#include <linux/kernel_stat.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/mc146818rtc.h> +#include <linux/irq.h> +#include <linux/timex.h> + +#include <asm/irq_cpu.h> +#include <asm/mipsregs.h> +#include <asm/ptrace.h> +#include <asm/debug.h> +#include <asm/rc32434/rc32434.h> + +static unsigned long r4k_offset; /* Amount to incr compare reg each time */ +static unsigned long r4k_cur; /* What counter should be at next timer irq */ +extern unsigned int mips_hpt_frequency; +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 rc32434_time_init(void) +{ + unsigned int est_freq, flags; + + local_irq_save(flags); + + printk("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("CPU frequency %d.%02d MHz\n", est_freq/1000000, + (est_freq%1000000)*100/1000000); + local_irq_restore(flags); +} + +void __init plat_timer_setup(struct irqaction *irq) +{ + /* we are using the cpu counter for timer interrupts */ + setup_irq(MIPS_CPU_TIMER_IRQ, irq); + + /* to generate the first timer interrupt */ + r4k_cur = (read_c0_count() + r4k_offset); + write_c0_compare(r4k_cur); +} + |