1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2014 ARM Limited
12 */
13
14 #include <linux/clocksource.h>
15 #include <linux/io.h>
16 #include <linux/of_address.h>
17 #include <linux/sched_clock.h>
18
19 #define SYS_24MHZ 0x05c
20
21 static void __iomem *versatile_sys_24mhz;
22
versatile_sys_24mhz_read(void)23 static u64 notrace versatile_sys_24mhz_read(void)
24 {
25 return readl(versatile_sys_24mhz);
26 }
27
versatile_sched_clock_init(struct device_node * node)28 static int __init versatile_sched_clock_init(struct device_node *node)
29 {
30 void __iomem *base = of_iomap(node, 0);
31
32 if (!base)
33 return -ENXIO;
34
35 versatile_sys_24mhz = base + SYS_24MHZ;
36
37 sched_clock_register(versatile_sys_24mhz_read, 32, 24000000);
38
39 return 0;
40 }
41 TIMER_OF_DECLARE(vexpress, "arm,vexpress-sysreg",
42 versatile_sched_clock_init);
43 TIMER_OF_DECLARE(versatile, "arm,versatile-sysreg",
44 versatile_sched_clock_init);
45
