| /* |
| * Copyright 2001 MontaVista Software Inc. |
| * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net |
| * Copyright (c) 2003, 2004 Maciej W. Rozycki |
| * |
| * Common time service routines for MIPS machines. |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2 of the License, or (at your |
| * option) any later version. |
| */ |
| #include <linux/bug.h> |
| #include <linux/clockchips.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/sched.h> |
| #include <linux/param.h> |
| #include <linux/time.h> |
| #include <linux/timex.h> |
| #include <linux/smp.h> |
| #include <linux/spinlock.h> |
| #include <linux/export.h> |
| |
| #include <asm/cpu-features.h> |
| #include <asm/cpu-type.h> |
| #include <asm/div64.h> |
| #include <asm/time.h> |
| |
| /* |
| * forward reference |
| */ |
| DEFINE_SPINLOCK(rtc_lock); |
| EXPORT_SYMBOL(rtc_lock); |
| |
| int __weak rtc_mips_set_time(unsigned long sec) |
| { |
| return -ENODEV; |
| } |
| |
| int __weak rtc_mips_set_mmss(unsigned long nowtime) |
| { |
| return rtc_mips_set_time(nowtime); |
| } |
| |
| int update_persistent_clock(struct timespec now) |
| { |
| return rtc_mips_set_mmss(now.tv_sec); |
| } |
| |
| static int null_perf_irq(void) |
| { |
| return 0; |
| } |
| |
| int (*perf_irq)(void) = null_perf_irq; |
| |
| EXPORT_SYMBOL(perf_irq); |
| |
| /* |
| * time_init() - it does the following things. |
| * |
| * 1) plat_time_init() - |
| * a) (optional) set up RTC routines, |
| * b) (optional) calibrate and set the mips_hpt_frequency |
| * (only needed if you intended to use cpu counter as timer interrupt |
| * source) |
| * 2) calculate a couple of cached variables for later usage |
| */ |
| |
| unsigned int mips_hpt_frequency; |
| |
| /* |
| * This function exists in order to cause an error due to a duplicate |
| * definition if platform code should have its own implementation. The hook |
| * to use instead is plat_time_init. plat_time_init does not receive the |
| * irqaction pointer argument anymore. This is because any function which |
| * initializes an interrupt timer now takes care of its own request_irq rsp. |
| * setup_irq calls and each clock_event_device should use its own |
| * struct irqrequest. |
| */ |
| void __init plat_timer_setup(void) |
| { |
| BUG(); |
| } |
| |
| static __init int cpu_has_mfc0_count_bug(void) |
| { |
| switch (current_cpu_type()) { |
| case CPU_R4000PC: |
| case CPU_R4000SC: |
| case CPU_R4000MC: |
| /* |
| * V3.0 is documented as suffering from the mfc0 from count bug. |
| * Afaik this is the last version of the R4000. Later versions |
| * were marketed as R4400. |
| */ |
| return 1; |
| |
| case CPU_R4400PC: |
| case CPU_R4400SC: |
| case CPU_R4400MC: |
| /* |
| * The published errata for the R4400 up to 3.0 say the CPU |
| * has the mfc0 from count bug. |
| */ |
| if ((current_cpu_data.processor_id & 0xff) <= 0x30) |
| return 1; |
| |
| /* |
| * we assume newer revisions are ok |
| */ |
| return 0; |
| } |
| |
| return 0; |
| } |
| |
| void __init time_init(void) |
| { |
| plat_time_init(); |
| |
| /* |
| * The use of the R4k timer as a clock event takes precedence; |
| * if reading the Count register might interfere with the timer |
| * interrupt, then we don't use the timer as a clock source. |
| * We may still use the timer as a clock source though if the |
| * timer interrupt isn't reliable; the interference doesn't |
| * matter then, because we don't use the interrupt. |
| */ |
| if (mips_clockevent_init() != 0 || !cpu_has_mfc0_count_bug()) |
| init_mips_clocksource(); |
| } |