LXR linux/arch/mips/sgi-ip27/ip27-timer.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
   4 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   5 */
   6#include <linux/bcd.h>
   7#include <linux/clockchips.h>
   8#include <linux/init.h>
   9#include <linux/kernel.h>
  10#include <linux/sched.h>
  11#include <linux/sched_clock.h>
  12#include <linux/interrupt.h>
  13#include <linux/kernel_stat.h>
  14#include <linux/param.h>
  15#include <linux/smp.h>
  16#include <linux/time.h>
  17#include <linux/timex.h>
  18#include <linux/mm.h>
  19#include <linux/platform_device.h>
  20
  21#include <asm/time.h>
  22#include <asm/sgialib.h>
  23#include <asm/sn/klconfig.h>
  24#include <asm/sn/arch.h>
  25#include <asm/sn/addrs.h>
  26#include <asm/sn/agent.h>
  27
  28#include "ip27-common.h"
  29
  30static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  31{
  32        unsigned int cpu = smp_processor_id();
  33        int slice = cputoslice(cpu);
  34        unsigned long cnt;
  35
  36        cnt = LOCAL_HUB_L(PI_RT_COUNT);
  37        cnt += delta;
  38        LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  39
  40        return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  41}
  42
  43static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  44static DEFINE_PER_CPU(char [11], hub_rt_name);
  45
  46static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  47{
  48        unsigned int cpu = smp_processor_id();
  49        struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  50        int slice = cputoslice(cpu);
  51
  52        /*
  53         * Ack
  54         */
  55        LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
  56        cd->event_handler(cd);
  57
  58        return IRQ_HANDLED;
  59}
  60
  61struct irqaction hub_rt_irqaction = {
  62        .handler        = hub_rt_counter_handler,
  63        .percpu_dev_id  = &hub_rt_clockevent,
  64        .flags          = IRQF_PERCPU | IRQF_TIMER,
  65        .name           = "hub-rt",
  66};
  67
  68/*
  69 * This is a hack; we really need to figure these values out dynamically
  70 *
  71 * Since 800 ns works very well with various HUB frequencies, such as
  72 * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
  73 *
  74 * Ralf: which clock rate is used to feed the counter?
  75 */
  76#define NSEC_PER_CYCLE          800
  77#define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
  78
  79void hub_rt_clock_event_init(void)
  80{
  81        unsigned int cpu = smp_processor_id();
  82        struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  83        unsigned char *name = per_cpu(hub_rt_name, cpu);
  84
  85        sprintf(name, "hub-rt %d", cpu);
  86        cd->name                = name;
  87        cd->features            = CLOCK_EVT_FEAT_ONESHOT;
  88        clockevent_set_clock(cd, CYCLES_PER_SEC);
  89        cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
  90        cd->max_delta_ticks     = 0xfffffffffffff;
  91        cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
  92        cd->min_delta_ticks     = 0x300;
  93        cd->rating              = 200;
  94        cd->irq                 = IP27_RT_TIMER_IRQ;
  95        cd->cpumask             = cpumask_of(cpu);
  96        cd->set_next_event      = rt_next_event;
  97        clockevents_register_device(cd);
  98
  99        enable_percpu_irq(IP27_RT_TIMER_IRQ, IRQ_TYPE_NONE);
 100}
 101
 102static void __init hub_rt_clock_event_global_init(void)
 103{
 104        irq_set_handler(IP27_RT_TIMER_IRQ, handle_percpu_devid_irq);
 105        irq_set_percpu_devid(IP27_RT_TIMER_IRQ);
 106        setup_percpu_irq(IP27_RT_TIMER_IRQ, &hub_rt_irqaction);
 107}
 108
 109static u64 hub_rt_read(struct clocksource *cs)
 110{
 111        return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 112}
 113
 114struct clocksource hub_rt_clocksource = {
 115        .name   = "HUB-RT",
 116        .rating = 200,
 117        .read   = hub_rt_read,
 118        .mask   = CLOCKSOURCE_MASK(52),
 119        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 120};
 121
 122static u64 notrace hub_rt_read_sched_clock(void)
 123{
 124        return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 125}
 126
 127static void __init hub_rt_clocksource_init(void)
 128{
 129        struct clocksource *cs = &hub_rt_clocksource;
 130
 131        clocksource_register_hz(cs, CYCLES_PER_SEC);
 132
 133        sched_clock_register(hub_rt_read_sched_clock, 52, CYCLES_PER_SEC);
 134}
 135
 136void __init plat_time_init(void)
 137{
 138        hub_rt_clocksource_init();
 139        hub_rt_clock_event_global_init();
 140        hub_rt_clock_event_init();
 141}
 142
 143void hub_rtc_init(nasid_t nasid)
 144{
 145
 146        /*
 147         * We only need to initialize the current node.
 148         * If this is not the current node then it is a cpuless
 149         * node and timeouts will not happen there.
 150         */
 151        if (get_nasid() == nasid) {
 152                LOCAL_HUB_S(PI_RT_EN_A, 1);
 153                LOCAL_HUB_S(PI_RT_EN_B, 1);
 154                LOCAL_HUB_S(PI_PROF_EN_A, 0);
 155                LOCAL_HUB_S(PI_PROF_EN_B, 0);
 156                LOCAL_HUB_S(PI_RT_COUNT, 0);
 157                LOCAL_HUB_S(PI_RT_PEND_A, 0);
 158                LOCAL_HUB_S(PI_RT_PEND_B, 0);
 159        }
 160}
 161