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/timer64.h>
24
25 static u32 sched_clock_multiplier;
26 #define SCHED_CLOCK_SHIFT 16
27
tsc_read(struct clocksource * cs)28 static cycle_t tsc_read(struct clocksource *cs)
29 {
30 return get_cycles();
31 }
32
33 static struct clocksource clocksource_tsc = {
34 .name = "timestamp",
35 .rating = 300,
36 .read = tsc_read,
37 .mask = CLOCKSOURCE_MASK(64),
38 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
39 };
40
41 /*
42 * scheduler clock - returns current time in nanoseconds.
43 */
sched_clock(void)44 u64 sched_clock(void)
45 {
46 u64 tsc = get_cycles();
47
48 return (tsc * sched_clock_multiplier) >> SCHED_CLOCK_SHIFT;
49 }
50
time_init(void)51 void time_init(void)
52 {
53 u64 tmp = (u64)NSEC_PER_SEC << SCHED_CLOCK_SHIFT;
54
55 do_div(tmp, c6x_core_freq);
56 sched_clock_multiplier = tmp;
57
58 clocksource_register_hz(&clocksource_tsc, c6x_core_freq);
59
60 /* write anything into TSCL to enable counting */
61 set_creg(TSCL, 0);
62
63 /* probe for timer64 event timer */
64 timer64_init();
65 }
66