1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Regents of the University of California
4 * Copyright (C) 2017 SiFive
7 #include <linux/acpi.h>
8 #include <linux/of_clk.h>
9 #include <linux/clockchips.h>
10 #include <linux/clocksource.h>
11 #include <linux/delay.h>
13 #include <asm/processor.h>
14 #include <asm/timex.h>
16 unsigned long riscv_timebase __ro_after_init;
17 EXPORT_SYMBOL_GPL(riscv_timebase);
19 void __init time_init(void)
21 struct device_node *cpu;
22 struct acpi_table_rhct *rhct;
27 cpu = of_find_node_by_path("/cpus");
28 if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
29 panic("RISC-V system with no 'timebase-frequency' in DTS\n");
32 riscv_timebase = prop;
35 status = acpi_get_table(ACPI_SIG_RHCT, 0, (struct acpi_table_header **)&rhct);
36 if (ACPI_FAILURE(status))
37 panic("RISC-V ACPI system with no RHCT table\n");
39 riscv_timebase = rhct->time_base_freq;
40 acpi_put_table((struct acpi_table_header *)rhct);
43 lpj_fine = riscv_timebase / HZ;
47 tick_setup_hrtimer_broadcast();