arch/mips/sgi-ip30/ip30-timer.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * ip30-timer.c: Clocksource/clockevent support for the
   4  *               HEART chip in SGI Octane (IP30) systems.
   5  *
   6  * Copyright (C) 2004-2007 Stanislaw Skowronek <skylark@unaligned.org>
   7  * Copyright (C) 2009 Johannes Dickgreber <tanzy@gmx.de>
   8  * Copyright (C) 2011 Joshua Kinard <kumba@gentoo.org>
   9  */
  10
  11 #include <linux/clocksource.h>
  12 #include <linux/cpumask.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/percpu.h>
  16 #include <linux/sched_clock.h>
  17
  18 #include <asm/time.h>
  19 #include <asm/cevt-r4k.h>
  20 #include <asm/sgi/heart.h>
  21
  22 static u64 ip30_heart_counter_read(struct clocksource *cs)
  23 {
  24         return heart_read(&heart_regs->count);
  25 }
  26
  27 struct clocksource ip30_heart_clocksource = {
  28         .name   = "HEART",
  29         .rating = 400,
  30         .read   = ip30_heart_counter_read,
  31         .mask   = CLOCKSOURCE_MASK(52),
  32         .flags  = (CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VALID_FOR_HRES),
  33 };
  34
  35 static u64 notrace ip30_heart_read_sched_clock(void)
  36 {
  37         return heart_read(&heart_regs->count);
  38 }
  39
  40 static void __init ip30_heart_clocksource_init(void)
  41 {
  42         struct clocksource *cs = &ip30_heart_clocksource;
  43
  44         clocksource_register_hz(cs, HEART_CYCLES_PER_SEC);
  45
  46         sched_clock_register(ip30_heart_read_sched_clock, 52,
  47                              HEART_CYCLES_PER_SEC);
  48 }
  49
  50 void __init plat_time_init(void)
  51 {
  52         int irq = get_c0_compare_int();
  53
  54         cp0_timer_irq_installed = 1;
  55         c0_compare_irqaction.percpu_dev_id = &mips_clockevent_device;
  56         c0_compare_irqaction.flags &= ~IRQF_SHARED;
  57         irq_set_handler(irq, handle_percpu_devid_irq);
  58         irq_set_percpu_devid(irq);
  59         setup_percpu_irq(irq, &c0_compare_irqaction);
  60         enable_percpu_irq(irq, IRQ_TYPE_NONE);
  61
  62         ip30_heart_clocksource_init();
  63 }