linux/arch/mips/sgi-ip27/ip27-timer.c
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   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/pgtable.h>
  23#include <asm/sgialib.h>
  24#include <asm/sn/ioc3.h>
  25#include <asm/sn/klconfig.h>
  26#include <asm/sn/arch.h>
  27#include <asm/sn/addrs.h>
  28#include <asm/sn/sn_private.h>
  29#include <asm/sn/sn0/ip27.h>
  30#include <asm/sn/sn0/hub.h>
  31
  32#define TICK_SIZE (tick_nsec / 1000)
  33
  34/* Includes for ioc3_init().  */
  35#include <asm/sn/types.h>
  36#include <asm/sn/sn0/addrs.h>
  37#include <asm/sn/sn0/hubni.h>
  38#include <asm/sn/sn0/hubio.h>
  39#include <asm/pci/bridge.h>
  40
  41static void enable_rt_irq(struct irq_data *d)
  42{
  43}
  44
  45static void disable_rt_irq(struct irq_data *d)
  46{
  47}
  48
  49static struct irq_chip rt_irq_type = {
  50        .name           = "SN HUB RT timer",
  51        .irq_mask       = disable_rt_irq,
  52        .irq_unmask     = enable_rt_irq,
  53};
  54
  55static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
  56{
  57        unsigned int cpu = smp_processor_id();
  58        int slice = cputoslice(cpu);
  59        unsigned long cnt;
  60
  61        cnt = LOCAL_HUB_L(PI_RT_COUNT);
  62        cnt += delta;
  63        LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
  64
  65        return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
  66}
  67
  68unsigned int rt_timer_irq;
  69
  70static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  71static DEFINE_PER_CPU(char [11], hub_rt_name);
  72
  73static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
  74{
  75        unsigned int cpu = smp_processor_id();
  76        struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
  77        int slice = cputoslice(cpu);
  78
  79        /*
  80         * Ack
  81         */
  82        LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
  83        cd->event_handler(cd);
  84
  85        return IRQ_HANDLED;
  86}
  87
  88struct irqaction hub_rt_irqaction = {
  89        .handler        = hub_rt_counter_handler,
  90        .flags          = IRQF_PERCPU | IRQF_TIMER,
  91        .name           = "hub-rt",
  92};
  93
  94/*
  95 * This is a hack; we really need to figure these values out dynamically
  96 *
  97 * Since 800 ns works very well with various HUB frequencies, such as
  98 * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
  99 *
 100 * Ralf: which clock rate is used to feed the counter?
 101 */
 102#define NSEC_PER_CYCLE          800
 103#define CYCLES_PER_SEC          (NSEC_PER_SEC / NSEC_PER_CYCLE)
 104
 105void hub_rt_clock_event_init(void)
 106{
 107        unsigned int cpu = smp_processor_id();
 108        struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
 109        unsigned char *name = per_cpu(hub_rt_name, cpu);
 110        int irq = rt_timer_irq;
 111
 112        sprintf(name, "hub-rt %d", cpu);
 113        cd->name                = name;
 114        cd->features            = CLOCK_EVT_FEAT_ONESHOT;
 115        clockevent_set_clock(cd, CYCLES_PER_SEC);
 116        cd->max_delta_ns        = clockevent_delta2ns(0xfffffffffffff, cd);
 117        cd->max_delta_ticks     = 0xfffffffffffff;
 118        cd->min_delta_ns        = clockevent_delta2ns(0x300, cd);
 119        cd->min_delta_ticks     = 0x300;
 120        cd->rating              = 200;
 121        cd->irq                 = irq;
 122        cd->cpumask             = cpumask_of(cpu);
 123        cd->set_next_event      = rt_next_event;
 124        clockevents_register_device(cd);
 125}
 126
 127static void __init hub_rt_clock_event_global_init(void)
 128{
 129        int irq;
 130
 131        do {
 132                smp_wmb();
 133                irq = rt_timer_irq;
 134                if (irq)
 135                        break;
 136
 137                irq = allocate_irqno();
 138                if (irq < 0)
 139                        panic("Allocation of irq number for timer failed");
 140        } while (xchg(&rt_timer_irq, irq));
 141
 142        irq_set_chip_and_handler(irq, &rt_irq_type, handle_percpu_irq);
 143        setup_irq(irq, &hub_rt_irqaction);
 144}
 145
 146static u64 hub_rt_read(struct clocksource *cs)
 147{
 148        return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 149}
 150
 151struct clocksource hub_rt_clocksource = {
 152        .name   = "HUB-RT",
 153        .rating = 200,
 154        .read   = hub_rt_read,
 155        .mask   = CLOCKSOURCE_MASK(52),
 156        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 157};
 158
 159static u64 notrace hub_rt_read_sched_clock(void)
 160{
 161        return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 162}
 163
 164static void __init hub_rt_clocksource_init(void)
 165{
 166        struct clocksource *cs = &hub_rt_clocksource;
 167
 168        clocksource_register_hz(cs, CYCLES_PER_SEC);
 169
 170        sched_clock_register(hub_rt_read_sched_clock, 52, CYCLES_PER_SEC);
 171}
 172
 173void __init plat_time_init(void)
 174{
 175        hub_rt_clocksource_init();
 176        hub_rt_clock_event_global_init();
 177        hub_rt_clock_event_init();
 178}
 179
 180void cpu_time_init(void)
 181{
 182        lboard_t *board;
 183        klcpu_t *cpu;
 184        int cpuid;
 185
 186        /* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
 187        board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
 188        if (!board)
 189                panic("Can't find board info for myself.");
 190
 191        cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
 192        cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
 193        if (!cpu)
 194                panic("No information about myself?");
 195
 196        printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
 197
 198        set_c0_status(SRB_TIMOCLK);
 199}
 200
 201void hub_rtc_init(cnodeid_t cnode)
 202{
 203
 204        /*
 205         * We only need to initialize the current node.
 206         * If this is not the current node then it is a cpuless
 207         * node and timeouts will not happen there.
 208         */
 209        if (get_compact_nodeid() == cnode) {
 210                LOCAL_HUB_S(PI_RT_EN_A, 1);
 211                LOCAL_HUB_S(PI_RT_EN_B, 1);
 212                LOCAL_HUB_S(PI_PROF_EN_A, 0);
 213                LOCAL_HUB_S(PI_PROF_EN_B, 0);
 214                LOCAL_HUB_S(PI_RT_COUNT, 0);
 215                LOCAL_HUB_S(PI_RT_PEND_A, 0);
 216                LOCAL_HUB_S(PI_RT_PEND_B, 0);
 217        }
 218}
 219
 220static int __init sgi_ip27_rtc_devinit(void)
 221{
 222        struct resource res;
 223
 224        memset(&res, 0, sizeof(res));
 225        res.start = XPHYSADDR(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base +
 226                              IOC3_BYTEBUS_DEV0);
 227        res.end = res.start + 32767;
 228        res.flags = IORESOURCE_MEM;
 229
 230        return IS_ERR(platform_device_register_simple("rtc-m48t35", -1,
 231                                                      &res, 1));
 232}
 233
 234/*
 235 * kludge make this a device_initcall after ioc3 resource conflicts
 236 * are resolved
 237 */
 238late_initcall(sgi_ip27_rtc_devinit);
 239