1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 *  Port on Texas Instruments TMS320C6x architecture
 4 *
 5 *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
 6 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
 7 */
 8
 9#include <linux/kernel.h>
10#include <linux/clocksource.h>
11#include <linux/errno.h>
12#include <linux/sched.h>
13#include <linux/param.h>
14#include <linux/string.h>
15#include <linux/mm.h>
16#include <linux/interrupt.h>
17#include <linux/timex.h>
18#include <linux/profile.h>
19
20#include <asm/special_insns.h>
21#include <asm/timer64.h>
22
23static u32 sched_clock_multiplier;
24#define SCHED_CLOCK_SHIFT 16
25
26static u64 tsc_read(struct clocksource *cs)
27{
28	return get_cycles();
29}
30
31static struct clocksource clocksource_tsc = {
32	.name		= "timestamp",
33	.rating		= 300,
34	.read		= tsc_read,
35	.mask		= CLOCKSOURCE_MASK(64),
36	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
37};
38
39/*
40 * scheduler clock - returns current time in nanoseconds.
41 */
42u64 sched_clock(void)
43{
44	u64 tsc = get_cycles();
45
46	return (tsc * sched_clock_multiplier) >> SCHED_CLOCK_SHIFT;
47}
48
49void __init time_init(void)
50{
51	u64 tmp = (u64)NSEC_PER_SEC << SCHED_CLOCK_SHIFT;
52
53	do_div(tmp, c6x_core_freq);
54	sched_clock_multiplier = tmp;
55
56	clocksource_register_hz(&clocksource_tsc, c6x_core_freq);
57
58	/* write anything into TSCL to enable counting */
59	set_creg(TSCL, 0);
60
61	/* probe for timer64 event timer */
62	timer64_init();
63}