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
21static void __iomem *versatile_sys_24mhz;
22
23static u64 notrace versatile_sys_24mhz_read(void)
24{
25	return readl(versatile_sys_24mhz);
26}
27
28static void __init versatile_sched_clock_init(struct device_node *node)
29{
30	void __iomem *base = of_iomap(node, 0);
31
32	if (!base)
33		return;
34
35	versatile_sys_24mhz = base + SYS_24MHZ;
36
37	sched_clock_register(versatile_sys_24mhz_read, 32, 24000000);
38}
39CLOCKSOURCE_OF_DECLARE(versatile, "arm,vexpress-sysreg",
40		       versatile_sched_clock_init);
41