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
17static 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
46static 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