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 /*
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 */
16
timer_interrupt(int irq,void * dev_id,struct pt_regs * regs)17 static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
18 {
19 static int count = 25;
20 unsigned char stat = __raw_readb(DUART_BASE + 0x14);
21 if (!(stat & 0x10))
22 return; /* Not for us */
23
24 /* Reset counter */
25 __raw_writeb(0x90, DUART_BASE + 8);
26
27 if (--count == 0) {
28 static int state = 1;
29 state ^= 1;
30 __raw_writeb(0x1a + state, INTCONT_BASE);
31 __raw_writeb(0x18 + state, INTCONT_BASE);
32 count = 50;
33 }
34
35 /* Wait for slow rise time */
36 __raw_readb(DUART_BASE + 0x14);
37 __raw_readb(DUART_BASE + 0x14);
38 __raw_readb(DUART_BASE + 0x14);
39 __raw_readb(DUART_BASE + 0x14);
40 __raw_readb(DUART_BASE + 0x14);
41 __raw_readb(DUART_BASE + 0x14);
42
43 do_timer(regs);
44 }
45
setup_timer(void)46 static inline void setup_timer(void)
47 {
48 int tick = 3686400 / 16 / 2 / 100;
49
50 __raw_writeb(tick & 0xff, DUART_BASE + 0x1c);
51 __raw_writeb(tick >> 8, DUART_BASE + 0x18);
52 __raw_writeb(0x80, DUART_BASE + 8);
53 __raw_writeb(0x10, DUART_BASE + 0x14);
54
55 timer_irq.handler = timer_interrupt;
56 timer_irq.flags = SA_SHIRQ;
57
58 setup_arm_irq(IRQ_TIMER, &timer_irq);
59 }
60