1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright (C) 2014 ARM Limited
5  */
6 
7 #include <linux/clocksource.h>
8 #include <linux/io.h>
9 #include <linux/of_address.h>
10 #include <linux/sched_clock.h>
11 
12 #define SYS_24MHZ 0x05c
13 
14 static void __iomem *versatile_sys_24mhz;
15 
16 static u64 notrace versatile_sys_24mhz_read(void)
17 {
18 	return readl(versatile_sys_24mhz);
19 }
20 
21 static int __init versatile_sched_clock_init(struct device_node *node)
22 {
23 	void __iomem *base = of_iomap(node, 0);
24 
25 	if (!base)
26 		return -ENXIO;
27 
28 	versatile_sys_24mhz = base + SYS_24MHZ;
29 
30 	sched_clock_register(versatile_sys_24mhz_read, 32, 24000000);
31 
32 	return 0;
33 }
34 TIMER_OF_DECLARE(vexpress, "arm,vexpress-sysreg",
35 		       versatile_sched_clock_init);
36 TIMER_OF_DECLARE(versatile, "arm,versatile-sysreg",
37 		       versatile_sched_clock_init);
38