include/asm-arm/arch-ebsa110/time.h

   1 /*
   2  * linux/include/asm-arm/arch-ebsa110/time.h
   3  *
   4  * Copyright (c) 1996,1997,1998 Russell King.
   5  *
   6  * No real time clock on the evalulation board!
   7  *
   8  * Changelog:
   9  *  10-Oct-1996 RMK     Created
  10  *  04-Dec-1997 RMK     Updated for new arch/arm/kernel/time.c
  11  *  07-Aug-1998 RMK     Updated for arch/arm/kernel/leds.c
  12  *  28-Dec-1998 APH     Made leds code optional
  13  */
  14
  15 #include <asm/leds.h>
  16
  17 #define MCLK_47_8
  18
  19 #if defined(MCLK_42_3)
  20 #define PIT1_COUNT 0xecbe
  21 #elif defined(MCLK_47_8)
  22 /*
  23  * This should be 0x10B43, but that doesn't exactly fit.
  24  * We run the timer interrupt at 5ms, and then divide it by
  25  * two in software...  This is so that the user processes
  26  * see exactly the same model whichever ARM processor they're
  27  * running on.
  28  */
  29 #define PIT1_COUNT 0x85A1
  30 #define DIVISOR 2
  31 #endif
  32
  33 static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
  34 {
  35         *PIT_T1 = (PIT1_COUNT) & 0xff;
  36         *PIT_T1 = (PIT1_COUNT) >> 8;
  37
  38 #ifdef DIVISOR
  39         {
  40                 static unsigned int divisor;
  41
  42                 if (divisor--)
  43                         return;
  44                 divisor = DIVISOR - 1;
  45         }
  46 #endif
  47         do_leds();
  48         do_timer(regs);
  49         do_profile(regs);
  50 }
  51
  52 /*
  53  * Set up timer interrupt.
  54  */
  55 extern __inline__ void setup_timer(void)
  56 {
  57         /*
  58          * Timer 1, mode 0, 16-bit, autoreload
  59          */
  60         *PIT_CTRL = 0x70;
  61
  62         /*
  63          * Refresh counter clocked at 47.8MHz/7 = 146.4ns
  64          * We want centi-second interrupts
  65          */
  66         *PIT_T1 = (PIT1_COUNT) & 0xff;
  67         *PIT_T1 = (PIT1_COUNT) >> 8;
  68
  69         timer_irq.handler = timer_interrupt;
  70
  71         setup_arm_irq(IRQ_EBSA110_TIMER0, &timer_irq);
  72 }
  73
  74