xref: /openbmc/linux/arch/riscv/kernel/time.c (revision 2cf1c348)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Regents of the University of California
4  * Copyright (C) 2017 SiFive
5  */
6 
7 #include <linux/of_clk.h>
8 #include <linux/clocksource.h>
9 #include <linux/delay.h>
10 #include <asm/sbi.h>
11 #include <asm/processor.h>
12 #include <asm/timex.h>
13 
14 unsigned long riscv_timebase __ro_after_init;
15 EXPORT_SYMBOL_GPL(riscv_timebase);
16 
17 void __init time_init(void)
18 {
19 	struct device_node *cpu;
20 	u32 prop;
21 
22 	cpu = of_find_node_by_path("/cpus");
23 	if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
24 		panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
25 	of_node_put(cpu);
26 	riscv_timebase = prop;
27 
28 	lpj_fine = riscv_timebase / HZ;
29 
30 	of_clk_init(NULL);
31 	timer_probe();
32 }
33 
34 void clocksource_arch_init(struct clocksource *cs)
35 {
36 #ifdef CONFIG_GENERIC_GETTIMEOFDAY
37 	cs->vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER;
38 #else
39 	cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
40 #endif
41 }
42