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/acpi.h> 8 #include <linux/of_clk.h> 9 #include <linux/clockchips.h> 10 #include <linux/clocksource.h> 11 #include <linux/delay.h> 12 #include <asm/sbi.h> 13 #include <asm/processor.h> 14 #include <asm/timex.h> 15 16 unsigned long riscv_timebase __ro_after_init; 17 EXPORT_SYMBOL_GPL(riscv_timebase); 18 time_init(void)19void __init time_init(void) 20 { 21 struct device_node *cpu; 22 struct acpi_table_rhct *rhct; 23 acpi_status status; 24 u32 prop; 25 26 if (acpi_disabled) { 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"); 30 31 of_node_put(cpu); 32 riscv_timebase = prop; 33 of_clk_init(NULL); 34 } else { 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"); 38 39 riscv_timebase = rhct->time_base_freq; 40 acpi_put_table((struct acpi_table_header *)rhct); 41 } 42 43 lpj_fine = riscv_timebase / HZ; 44 45 timer_probe(); 46 47 tick_setup_hrtimer_broadcast(); 48 } 49