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

   1 /**************************************************************************
   2  *
   3  *  BRIEF MODULE DESCRIPTION
   4  *     timer routines for IDT EB434 boards
   5  *
   6  *  Copyright 2004 IDT Inc. (rischelp@idt.com)
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  14  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  15  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  16  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  17  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  19  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  20  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  21  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  *
  24  *  You should have received a copy of the  GNU General Public License along
  25  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  26  *  675 Mass Ave, Cambridge, MA 02139, USA.
  27  *
  28  *
  29  **************************************************************************
  30  * May 2004 rkt, neb
  31  *
  32  * Initial Release
  33  *
  34  *
  35  *
  36  **************************************************************************
  37  */
  38
  39 #include <linux/autoconf.h>
  40 #include <linux/init.h>
  41 #include <linux/kernel_stat.h>
  42 #include <linux/sched.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/mc146818rtc.h>
  45 #include <linux/irq.h>
  46 #include <linux/timex.h>
  47
  48 #include <linux/param.h>
  49 #include <asm/mipsregs.h>
  50 #include <asm/ptrace.h>
  51 #include <asm/time.h>
  52 #include <asm/hardirq.h>
  53
  54 #include <asm/mipsregs.h>
  55 #include <asm/ptrace.h>
  56 #include <asm/debug.h>
  57 #include <asm/time.h>
  58
  59 #include <asm/idt-boards/rc32434/rc32434.h>
  60
  61 static unsigned long r4k_offset;        /* Amount to incr compare reg each time */
  62 static unsigned long r4k_cur;   /* What counter should be at next timer irq */
  63
  64 extern unsigned int idt_cpu_freq;
  65
  66 static unsigned long __init cal_r4koff(void)
  67 {
  68         mips_hpt_frequency = idt_cpu_freq * IDT_CLOCK_MULT / 2;
  69         return (mips_hpt_frequency / HZ);
  70 }
  71
  72 void __init aruba_time_init(void)
  73 {
  74         unsigned int est_freq, flags;
  75         local_irq_save(flags);
  76
  77         printk("calculating r4koff... ");
  78         r4k_offset = cal_r4koff();
  79         printk("%08lx(%d)\n", r4k_offset, (int)r4k_offset);
  80
  81         est_freq = 2 * r4k_offset * HZ;
  82         est_freq += 5000;       /* round */
  83         est_freq -= est_freq % 10000;
  84         printk("CPU frequency %d.%02d MHz\n", est_freq / 1000000,
  85                (est_freq % 1000000) * 100 / 1000000);
  86         local_irq_restore(flags);
  87
  88 }
  89
  90 void __init plat_timer_setup(struct irqaction *irq)
  91 {
  92         /* we are using the cpu counter for timer interrupts */
  93         setup_irq(MIPS_CPU_TIMER_IRQ, irq);
  94
  95         /* to generate the first timer interrupt */
  96         r4k_cur = (read_c0_count() + r4k_offset);
  97         write_c0_compare(r4k_cur);
  98
  99 }
 100
 101 asmlinkage void aruba_timer_interrupt(struct pt_regs *regs)
 102 {
 103         int irq = MIPS_CPU_TIMER_IRQ;
 104
 105         irq_enter();
 106         kstat_this_cpu.irqs[irq]++;
 107
 108         timer_interrupt(irq, NULL);
 109         irq_exit();
 110 }