openwrt/target/linux/aruba-2.6/files/arch/mips/aruba/time.c

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/**************************************************************************
*
* BRIEF MODULE DESCRIPTION
* timer routines for IDT EB434 boards
*
* Copyright 2004 IDT Inc. (rischelp@idt.com)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
**************************************************************************
* May 2004 rkt, neb
*
* Initial Release
*
*
*
**************************************************************************
*/
#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 <linux/param.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
#include <asm/time.h>
#include <asm/hardirq.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
#include <asm/debug.h>
#include <asm/time.h>
#include <asm/idt-boards/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 idt_cpu_freq;
static unsigned long __init cal_r4koff(void)
{
mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2;
return (mips_hpt_frequency / HZ);
}
void __init aruba_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);
}
asmlinkage void aruba_timer_interrupt(struct pt_regs *regs)
{
int irq = MIPS_CPU_TIMER_IRQ;
irq_enter();
kstat_this_cpu.irqs[irq]++;
timer_interrupt(irq, NULL);
irq_exit();
}