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

   1 /*
   2  * linux/include/asm-arm/arch-nexuspci/time.h
   3  *
   4  * Copyright (c) 1997, 1998, 1999, 2000 FutureTV Labs Ltd.
   5  *
   6  * The FTV PCI card has no real-time clock.  We get timer ticks from the
   7  * SCC chip.
   8  */
   9
  10 static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
  11 {
  12         static int count = 25;
  13         unsigned char stat = __raw_readb(DUART_BASE + 0x14);
  14         if (!(stat & 0x10))
  15                 return;         /* Not for us */
  16
  17         /* Reset counter */
  18         __raw_writeb(0x90, DUART_BASE + 8);
  19
  20         if (--count == 0) {
  21                 static int state = 1;
  22                 state ^= 1;
  23                 __raw_writeb(0x1a + state, INTCONT_BASE);
  24                 __raw_writeb(0x18 + state, INTCONT_BASE);
  25                 count = 50;
  26         }
  27
  28         /* Wait for slow rise time */
  29         __raw_readb(DUART_BASE + 0x14);
  30         __raw_readb(DUART_BASE + 0x14);
  31         __raw_readb(DUART_BASE + 0x14);
  32         __raw_readb(DUART_BASE + 0x14);
  33         __raw_readb(DUART_BASE + 0x14);
  34         __raw_readb(DUART_BASE + 0x14);
  35
  36         do_timer(regs);
  37 }
  38
  39 extern __inline__ void setup_timer(void)
  40 {
  41         int tick = 3686400 / 16 / 2 / 100;
  42
  43         __raw_writeb(tick & 0xff, DUART_BASE + 0x1c);
  44         __raw_writeb(tick >> 8, DUART_BASE + 0x18);
  45         __raw_writeb(0x80, DUART_BASE + 8);
  46         __raw_writeb(0x10, DUART_BASE + 0x14);
  47
  48         timer_irq.handler = timer_interrupt;
  49         timer_irq.flags = SA_SHIRQ;
  50
  51         setup_arm_irq(IRQ_TIMER, &timer_irq);
  52 }