LXR linux/drivers/clocksource/numachip.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *
   4 * Copyright (C) 2015 Numascale AS. All rights reserved.
   5 */
   6
   7#include <linux/clockchips.h>
   8
   9#include <asm/irq.h>
  10#include <asm/numachip/numachip.h>
  11#include <asm/numachip/numachip_csr.h>
  12
  13static DEFINE_PER_CPU(struct clock_event_device, numachip2_ced);
  14
  15static cycles_t numachip2_timer_read(struct clocksource *cs)
  16{
  17        return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW);
  18}
  19
  20static struct clocksource numachip2_clocksource = {
  21        .name            = "numachip2",
  22        .rating          = 295,
  23        .read            = numachip2_timer_read,
  24        .mask            = CLOCKSOURCE_MASK(64),
  25        .flags           = CLOCK_SOURCE_IS_CONTINUOUS,
  26        .mult            = 1,
  27        .shift           = 0,
  28};
  29
  30static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced)
  31{
  32        numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(),
  33                delta);
  34        return 0;
  35}
  36
  37static const struct clock_event_device numachip2_clockevent __initconst = {
  38        .name            = "numachip2",
  39        .rating          = 400,
  40        .set_next_event  = numachip2_set_next_event,
  41        .features        = CLOCK_EVT_FEAT_ONESHOT,
  42        .mult            = 1,
  43        .shift           = 0,
  44        .min_delta_ns    = 1250,
  45        .min_delta_ticks = 1250,
  46        .max_delta_ns    = LONG_MAX,
  47        .max_delta_ticks = LONG_MAX,
  48};
  49
  50static void numachip_timer_interrupt(void)
  51{
  52        struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
  53
  54        ced->event_handler(ced);
  55}
  56
  57static __init void numachip_timer_each(struct work_struct *work)
  58{
  59        unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff;
  60        struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced);
  61
  62        /* Setup IPI vector to local core and relative timing mode */
  63        numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(),
  64                (3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) |
  65                (local_apicid << 6));
  66
  67        *ced = numachip2_clockevent;
  68        ced->cpumask = cpumask_of(smp_processor_id());
  69        clockevents_register_device(ced);
  70}
  71
  72static int __init numachip_timer_init(void)
  73{
  74        if (numachip_system != 2)
  75                return -ENODEV;
  76
  77        /* Reset timer */
  78        numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0);
  79        clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC);
  80
  81        /* Setup per-cpu clockevents */
  82        x86_platform_ipi_callback = numachip_timer_interrupt;
  83        schedule_on_each_cpu(&numachip_timer_each);
  84
  85        return 0;
  86}
  87
  88arch_initcall(numachip_timer_init);
  89