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/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
  41 static void enable_rt_irq(struct irq_data *d)
  42 {
  43 }
  44
  45 static void disable_rt_irq(struct irq_data *d)
  46 {
  47 }
  48
  49 static 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
  55 static 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
  68 unsigned int rt_timer_irq;
  69
  70 static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
  71 static DEFINE_PER_CPU(char [11], hub_rt_name);
  72
  73 static 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
  88 struct 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
 105 void 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
 127 static 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
 146 static u64 hub_rt_read(struct clocksource *cs)
 147 {
 148         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 149 }
 150
 151 struct 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
 159 static u64 notrace hub_rt_read_sched_clock(void)
 160 {
 161         return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
 162 }
 163
 164 static 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
 173 void __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
 180 void 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
 201 void 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
 220 static 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  */
 238 late_initcall(sgi_ip27_rtc_devinit);