1 #include <linux/clocksource.h>
2 #include <linux/sched_clock.h>
3 #include <linux/of_address.h>
4 #include <linux/printk.h>
5 #include <linux/delay.h>
6 #include <linux/init.h>
7 #include <linux/clk.h>
8
9 static void __iomem *xtal_in_cnt;
10 static struct delay_timer delay_timer;
11
read_xtal_counter(void)12 static unsigned long notrace read_xtal_counter(void)
13 {
14 return readl_relaxed(xtal_in_cnt);
15 }
16
read_sched_clock(void)17 static u64 notrace read_sched_clock(void)
18 {
19 return read_xtal_counter();
20 }
21
read_clocksource(struct clocksource * cs)22 static cycle_t read_clocksource(struct clocksource *cs)
23 {
24 return read_xtal_counter();
25 }
26
27 static struct clocksource tango_xtal = {
28 .name = "tango-xtal",
29 .rating = 350,
30 .read = read_clocksource,
31 .mask = CLOCKSOURCE_MASK(32),
32 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
33 };
34
tango_clocksource_init(struct device_node * np)35 static void __init tango_clocksource_init(struct device_node *np)
36 {
37 struct clk *clk;
38 int xtal_freq, ret;
39
40 xtal_in_cnt = of_iomap(np, 0);
41 if (xtal_in_cnt == NULL) {
42 pr_err("%s: invalid address\n", np->full_name);
43 return;
44 }
45
46 clk = of_clk_get(np, 0);
47 if (IS_ERR(clk)) {
48 pr_err("%s: invalid clock\n", np->full_name);
49 return;
50 }
51
52 xtal_freq = clk_get_rate(clk);
53 delay_timer.freq = xtal_freq;
54 delay_timer.read_current_timer = read_xtal_counter;
55
56 ret = clocksource_register_hz(&tango_xtal, xtal_freq);
57 if (ret != 0) {
58 pr_err("%s: registration failed\n", np->full_name);
59 return;
60 }
61
62 sched_clock_register(read_sched_clock, 32, xtal_freq);
63 register_current_timer_delay(&delay_timer);
64 }
65
66 CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);
67