1/*
2 *  Port on Texas Instruments TMS320C6x architecture
3 *
4 *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
5 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
6 *
7 *  This program is free software; you can redistribute it and/or modify
8 *  it under the terms of the GNU General Public License version 2 as
9 *  published by the Free Software Foundation.
10 */
11
12#include <linux/kernel.h>
13#include <linux/clocksource.h>
14#include <linux/errno.h>
15#include <linux/sched.h>
16#include <linux/param.h>
17#include <linux/string.h>
18#include <linux/mm.h>
19#include <linux/interrupt.h>
20#include <linux/timex.h>
21#include <linux/profile.h>
22
23#include <asm/special_insns.h>
24#include <asm/timer64.h>
25
26static u32 sched_clock_multiplier;
27#define SCHED_CLOCK_SHIFT 16
28
29static cycle_t tsc_read(struct clocksource *cs)
30{
31	return get_cycles();
32}
33
34static struct clocksource clocksource_tsc = {
35	.name		= "timestamp",
36	.rating		= 300,
37	.read		= tsc_read,
38	.mask		= CLOCKSOURCE_MASK(64),
39	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
40};
41
42/*
43 * scheduler clock - returns current time in nanoseconds.
44 */
45u64 sched_clock(void)
46{
47	u64 tsc = get_cycles();
48
49	return (tsc * sched_clock_multiplier) >> SCHED_CLOCK_SHIFT;
50}
51
52void time_init(void)
53{
54	u64 tmp = (u64)NSEC_PER_SEC << SCHED_CLOCK_SHIFT;
55
56	do_div(tmp, c6x_core_freq);
57	sched_clock_multiplier = tmp;
58
59	clocksource_register_hz(&clocksource_tsc, c6x_core_freq);
60
61	/* write anything into TSCL to enable counting */
62	set_creg(TSCL, 0);
63
64	/* probe for timer64 event timer */
65	timer64_init();
66}
67