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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copytight (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
   4  * Copytight (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
  30 static 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
  43 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  44 static DEFINE_PER_CPU(char [11], hub_rt_name);
  45
  46 static 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
  61 struct 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
  79 void 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
 102 static 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
 109 static u64 hub_rt_read(struct clocksource *cs)
 110 {
 111         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 112 }
 113
 114 struct 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
 122 static u64 notrace hub_rt_read_sched_clock(void)
 123 {
 124         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 125 }
 126
 127 static 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
 136 void __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
 143 void 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 }