| 1 | /* |
| 2 | * arch/ubicom32/kernel/timer_broadcast.c |
| 3 | * Implements a dummy clock event for each cpu. |
| 4 | * |
| 5 | * Copyright (C) 2008 Paul Mundt |
| 6 | * (C) Copyright 2009, Ubicom, Inc. |
| 7 | * |
| 8 | * This file is part of the Ubicom32 Linux Kernel Port. |
| 9 | * |
| 10 | * The Ubicom32 Linux Kernel Port is free software: you can redistribute |
| 11 | * it and/or modify it under the terms of the GNU General Public License |
| 12 | * as published by the Free Software Foundation, either version 2 of the |
| 13 | * License, or (at your option) any later version. |
| 14 | * |
| 15 | * The Ubicom32 Linux Kernel Port is distributed in the hope that it |
| 16 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 17 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 18 | * the GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with the Ubicom32 Linux Kernel Port. If not, |
| 22 | * see <http://www.gnu.org/licenses/>. |
| 23 | * |
| 24 | * Ubicom32 implementation derived from (with many thanks): |
| 25 | * arch/m68knommu |
| 26 | * arch/blackfin |
| 27 | * arch/parisc |
| 28 | * arch/arm |
| 29 | * arch/sh |
| 30 | */ |
| 31 | #include <linux/init.h> |
| 32 | #include <linux/kernel.h> |
| 33 | #include <linux/delay.h> |
| 34 | #include <linux/device.h> |
| 35 | #include <linux/smp.h> |
| 36 | #include <linux/jiffies.h> |
| 37 | #include <linux/percpu.h> |
| 38 | #include <linux/clockchips.h> |
| 39 | #include <linux/irq.h> |
| 40 | |
| 41 | static DEFINE_PER_CPU(struct clock_event_device, local_clockevent); |
| 42 | |
| 43 | /* |
| 44 | * The broadcast trick only works when the timer will be used in a periodic mode. |
| 45 | * If the user has configured either NO_HZ or HIGH_RES_TIMERS they must have |
| 46 | * a per cpu timer. |
| 47 | */ |
| 48 | #if defined(CONFIG_NO_HZ) || defined(CONFIG_HIGH_RES_TIMERS) |
| 49 | #error "Tickless and High Resolution Timers require per-CPU local timers: CONFIG_LOCAL_TIMERS" |
| 50 | #endif |
| 51 | |
| 52 | /* |
| 53 | * local_timer_interrupt() |
| 54 | * Used on SMP for local timer interrupt sent via an IPI. |
| 55 | */ |
| 56 | void local_timer_interrupt(void) |
| 57 | { |
| 58 | struct clock_event_device *dev = &__get_cpu_var(local_clockevent); |
| 59 | |
| 60 | dev->event_handler(dev); |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * dummy_timer_set_next_event() |
| 65 | * Cause the timer to go off "cycles" from now. |
| 66 | */ |
| 67 | static int dummy_timer_set_next_event(unsigned long cycles, struct clock_event_device *dev) |
| 68 | { |
| 69 | return 0; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * dummy_timer_set_mode() |
| 74 | * Do Nothing. |
| 75 | */ |
| 76 | static void dummy_timer_set_mode(enum clock_event_mode mode, |
| 77 | struct clock_event_device *clk) |
| 78 | { |
| 79 | } |
| 80 | |
| 81 | /* |
| 82 | * local_timer_setup() |
| 83 | * Adds a clock event for the specified cpu. |
| 84 | */ |
| 85 | int __cpuinit local_timer_setup(unsigned int cpu) |
| 86 | { |
| 87 | struct clock_event_device *dev = &per_cpu(local_clockevent, cpu); |
| 88 | |
| 89 | dev->name = "timer-dummy"; |
| 90 | dev->features = CLOCK_EVT_FEAT_DUMMY; |
| 91 | dev->rating = 200; |
| 92 | dev->mult = 1; |
| 93 | dev->set_mode = dummy_timer_set_mode; |
| 94 | dev->set_next_event = dummy_timer_set_next_event; |
| 95 | dev->broadcast = smp_timer_broadcast; |
| 96 | dev->cpumask = cpumask_of_cpu(cpu); |
| 97 | dev->irq = -1; |
| 98 | printk(KERN_NOTICE "timer[%d]: %s - created\n", dev->irq, dev->name); |
| 99 | |
| 100 | clockevents_register_device(dev); |
| 101 | return 0; |
| 102 | } |
| 103 | |
