| 1 | /* |
| 2 | * arch/ubicom32/kernel/timer_tick.c |
| 3 | * Impelemets a perodic timer. |
| 4 | * |
| 5 | * (C) Copyright 2009, Ubicom, Inc. |
| 6 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds |
| 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 | */ |
| 29 | |
| 30 | #include <linux/profile.h> |
| 31 | |
| 32 | #include <asm/ip5000.h> |
| 33 | #include <asm/machdep.h> |
| 34 | #if defined(CONFIG_SMP) |
| 35 | #include <asm/smp.h> |
| 36 | #endif |
| 37 | |
| 38 | static unsigned int timervector; |
| 39 | static unsigned int frequency; |
| 40 | |
| 41 | /* |
| 42 | * timer_tick() |
| 43 | * Kernel system timer support. Needs to keep up the real-time clock, |
| 44 | * as well as call the "do_timer()" routine every clocktick. |
| 45 | */ |
| 46 | static irqreturn_t timer_tick(int irq, void *dummy) |
| 47 | { |
| 48 | int ticks; |
| 49 | |
| 50 | BUG_ON(!irqs_disabled()); |
| 51 | ticks = timer_reset(timervector, frequency); |
| 52 | |
| 53 | write_seqlock(&xtime_lock); |
| 54 | do_timer(ticks); |
| 55 | write_sequnlock(&xtime_lock); |
| 56 | |
| 57 | update_process_times(user_mode(get_irq_regs())); |
| 58 | profile_tick(CPU_PROFILING); |
| 59 | |
| 60 | #if defined(CONFIG_SMP) |
| 61 | smp_send_timer_all(); |
| 62 | #endif |
| 63 | return(IRQ_HANDLED); |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Data used by setup_irq for the timer. |
| 68 | */ |
| 69 | static struct irqaction timer_irq = { |
| 70 | .name = "timer", |
| 71 | .flags = IRQF_DISABLED | IRQF_TIMER, |
| 72 | .handler = timer_tick, |
| 73 | }; |
| 74 | |
| 75 | /* |
| 76 | * timer_tick_init() |
| 77 | * Implements a periodic timer |
| 78 | * |
| 79 | * This implementation directly calls the timer_tick() and move |
| 80 | * the Linux kernel forward. This is used when the user has not |
| 81 | * selected GENERIC_CLOCKEVENTS. |
| 82 | */ |
| 83 | void timer_tick_init(void) |
| 84 | { |
| 85 | /* |
| 86 | * Now allocate a timer to ourselves. |
| 87 | */ |
| 88 | timervector = timer_alloc(); |
| 89 | if (timervector == -1) { |
| 90 | printk(KERN_WARNING "where did the timer go?\n"); |
| 91 | return; |
| 92 | } |
| 93 | |
| 94 | setup_irq(timervector, &timer_irq); |
| 95 | |
| 96 | /* |
| 97 | * Get the frequency from the processor device tree node or use |
| 98 | * the default if not available. We will store this as the frequency |
| 99 | * of the timer to avoid future calculations. |
| 100 | */ |
| 101 | frequency = processor_frequency(); |
| 102 | if (frequency == 0) { |
| 103 | frequency = CLOCK_TICK_RATE; |
| 104 | } |
| 105 | frequency /= CONFIG_HZ; |
| 106 | |
| 107 | printk(KERN_NOTICE "timer will interrupt every: %d cycles\n", frequency); |
| 108 | timer_set(timervector, frequency); |
| 109 | } |
| 110 | |
