1 /*
2 * linux/arch/m68k/hp300/time.c
3 *
4 * Copyright (C) 1998 Philip Blundell <philb@gnu.org>
5 *
6 * This file contains the HP300-specific time handling code.
7 */
8
9 #include <asm/ptrace.h>
10 #include <linux/types.h>
11 #include <linux/init.h>
12 #include <linux/sched.h>
13 #include <linux/kernel_stat.h>
14 #include <linux/interrupt.h>
15 #include <asm/machdep.h>
16 #include <asm/irq.h>
17 #include <asm/io.h>
18 #include <asm/system.h>
19 #include <asm/traps.h>
20 #include "ints.h"
21
22 /* Clock hardware definitions */
23
24 #define CLOCKBASE 0xf05f8000
25
26 #define CLKCR1 0x1
27 #define CLKCR2 0x3
28 #define CLKCR3 CLKCR1
29 #define CLKSR CLKCR2
30 #define CLKMSB1 0x5
31 #define CLKMSB2 0x9
32 #define CLKMSB3 0xD
33
34 /* This is for machines which generate the exact clock. */
35 #define USECS_PER_JIFFY (1000000/HZ)
36
37 #define INTVAL ((10000 / 4) - 1)
38
hp300_tick(int irq,void * dev_id,struct pt_regs * regs)39 static void hp300_tick(int irq, void *dev_id, struct pt_regs *regs)
40 {
41 unsigned long tmp;
42 void (*vector)(int, void *, struct pt_regs *) = dev_id;
43 in_8(CLOCKBASE + CLKSR);
44 asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
45 vector(irq, NULL, regs);
46 }
47
hp300_gettimeoffset(void)48 unsigned long hp300_gettimeoffset(void)
49 {
50 /* Read current timer 1 value */
51 unsigned char lsb, msb1, msb2;
52 unsigned short ticks;
53
54 msb1 = in_8(CLOCKBASE + 5);
55 lsb = in_8(CLOCKBASE + 7);
56 msb2 = in_8(CLOCKBASE + 5);
57 if (msb1 != msb2)
58 /* A carry happened while we were reading. Read it again */
59 lsb = in_8(CLOCKBASE + 7);
60 ticks = INTVAL - ((msb2 << 8) | lsb);
61 return (USECS_PER_JIFFY * ticks) / INTVAL;
62 }
63
hp300_sched_init(void (* vector)(int,void *,struct pt_regs *))64 void __init hp300_sched_init(void (*vector)(int, void *, struct pt_regs *))
65 {
66 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
67 out_8(CLOCKBASE + CLKCR1, 0x1); /* reset */
68
69 asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
70
71 sys_request_irq(6, hp300_tick, IRQ_FLG_STD, "timer tick", vector);
72
73 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
74 out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
75 }
76