linux/arch/sparc/kernel/time_32.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* linux/arch/sparc/kernel/time.c
   3 *
   4 * Copyright (C) 1995 David S. Miller (davem@davemloft.net)
   5 * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
   6 *
   7 * Chris Davis (cdavis@cois.on.ca) 03/27/1998
   8 * Added support for the intersil on the sun4/4200
   9 *
  10 * Gleb Raiko (rajko@mech.math.msu.su) 08/18/1998
  11 * Support for MicroSPARC-IIep, PCI CPU.
  12 *
  13 * This file handles the Sparc specific time handling details.
  14 *
  15 * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
  16 *              "A Kernel Model for Precision Timekeeping" by Dave Mills
  17 */
  18#include <linux/errno.h>
  19#include <linux/module.h>
  20#include <linux/sched.h>
  21#include <linux/kernel.h>
  22#include <linux/param.h>
  23#include <linux/string.h>
  24#include <linux/mm.h>
  25#include <linux/interrupt.h>
  26#include <linux/time.h>
  27#include <linux/rtc/m48t59.h>
  28#include <linux/timex.h>
  29#include <linux/clocksource.h>
  30#include <linux/clockchips.h>
  31#include <linux/init.h>
  32#include <linux/pci.h>
  33#include <linux/ioport.h>
  34#include <linux/profile.h>
  35#include <linux/of.h>
  36#include <linux/of_device.h>
  37#include <linux/platform_device.h>
  38
  39#include <asm/mc146818rtc.h>
  40#include <asm/oplib.h>
  41#include <asm/timex.h>
  42#include <asm/timer.h>
  43#include <asm/irq.h>
  44#include <asm/io.h>
  45#include <asm/idprom.h>
  46#include <asm/page.h>
  47#include <asm/pcic.h>
  48#include <asm/irq_regs.h>
  49#include <asm/setup.h>
  50
  51#include "kernel.h"
  52#include "irq.h"
  53
  54static __cacheline_aligned_in_smp DEFINE_SEQLOCK(timer_cs_lock);
  55static __volatile__ u64 timer_cs_internal_counter = 0;
  56static char timer_cs_enabled = 0;
  57
  58static struct clock_event_device timer_ce;
  59static char timer_ce_enabled = 0;
  60
  61#ifdef CONFIG_SMP
  62DEFINE_PER_CPU(struct clock_event_device, sparc32_clockevent);
  63#endif
  64
  65DEFINE_SPINLOCK(rtc_lock);
  66EXPORT_SYMBOL(rtc_lock);
  67
  68unsigned long profile_pc(struct pt_regs *regs)
  69{
  70        extern char __copy_user_begin[], __copy_user_end[];
  71        extern char __bzero_begin[], __bzero_end[];
  72
  73        unsigned long pc = regs->pc;
  74
  75        if (in_lock_functions(pc) ||
  76            (pc >= (unsigned long) __copy_user_begin &&
  77             pc < (unsigned long) __copy_user_end) ||
  78            (pc >= (unsigned long) __bzero_begin &&
  79             pc < (unsigned long) __bzero_end))
  80                pc = regs->u_regs[UREG_RETPC];
  81        return pc;
  82}
  83
  84EXPORT_SYMBOL(profile_pc);
  85
  86volatile u32 __iomem *master_l10_counter;
  87
  88irqreturn_t notrace timer_interrupt(int dummy, void *dev_id)
  89{
  90        if (timer_cs_enabled) {
  91                write_seqlock(&timer_cs_lock);
  92                timer_cs_internal_counter++;
  93                sparc_config.clear_clock_irq();
  94                write_sequnlock(&timer_cs_lock);
  95        } else {
  96                sparc_config.clear_clock_irq();
  97        }
  98
  99        if (timer_ce_enabled)
 100                timer_ce.event_handler(&timer_ce);
 101
 102        return IRQ_HANDLED;
 103}
 104
 105static int timer_ce_shutdown(struct clock_event_device *evt)
 106{
 107        timer_ce_enabled = 0;
 108        smp_mb();
 109        return 0;
 110}
 111
 112static int timer_ce_set_periodic(struct clock_event_device *evt)
 113{
 114        timer_ce_enabled = 1;
 115        smp_mb();
 116        return 0;
 117}
 118
 119static __init void setup_timer_ce(void)
 120{
 121        struct clock_event_device *ce = &timer_ce;
 122
 123        BUG_ON(smp_processor_id() != boot_cpu_id);
 124
 125        ce->name     = "timer_ce";
 126        ce->rating   = 100;
 127        ce->features = CLOCK_EVT_FEAT_PERIODIC;
 128        ce->set_state_shutdown = timer_ce_shutdown;
 129        ce->set_state_periodic = timer_ce_set_periodic;
 130        ce->tick_resume = timer_ce_set_periodic;
 131        ce->cpumask  = cpu_possible_mask;
 132        ce->shift    = 32;
 133        ce->mult     = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
 134                              ce->shift);
 135        clockevents_register_device(ce);
 136}
 137
 138static unsigned int sbus_cycles_offset(void)
 139{
 140        u32 val, offset;
 141
 142        val = sbus_readl(master_l10_counter);
 143        offset = (val >> TIMER_VALUE_SHIFT) & TIMER_VALUE_MASK;
 144
 145        /* Limit hit? */
 146        if (val & TIMER_LIMIT_BIT)
 147                offset += sparc_config.cs_period;
 148
 149        return offset;
 150}
 151
 152static u64 timer_cs_read(struct clocksource *cs)
 153{
 154        unsigned int seq, offset;
 155        u64 cycles;
 156
 157        do {
 158                seq = read_seqbegin(&timer_cs_lock);
 159
 160                cycles = timer_cs_internal_counter;
 161                offset = sparc_config.get_cycles_offset();
 162        } while (read_seqretry(&timer_cs_lock, seq));
 163
 164        /* Count absolute cycles */
 165        cycles *= sparc_config.cs_period;
 166        cycles += offset;
 167
 168        return cycles;
 169}
 170
 171static struct clocksource timer_cs = {
 172        .name   = "timer_cs",
 173        .rating = 100,
 174        .read   = timer_cs_read,
 175        .mask   = CLOCKSOURCE_MASK(64),
 176        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 177};
 178
 179static __init int setup_timer_cs(void)
 180{
 181        timer_cs_enabled = 1;
 182        return clocksource_register_hz(&timer_cs, sparc_config.clock_rate);
 183}
 184
 185#ifdef CONFIG_SMP
 186static int percpu_ce_shutdown(struct clock_event_device *evt)
 187{
 188        int cpu = cpumask_first(evt->cpumask);
 189
 190        sparc_config.load_profile_irq(cpu, 0);
 191        return 0;
 192}
 193
 194static int percpu_ce_set_periodic(struct clock_event_device *evt)
 195{
 196        int cpu = cpumask_first(evt->cpumask);
 197
 198        sparc_config.load_profile_irq(cpu, SBUS_CLOCK_RATE / HZ);
 199        return 0;
 200}
 201
 202static int percpu_ce_set_next_event(unsigned long delta,
 203                                    struct clock_event_device *evt)
 204{
 205        int cpu = cpumask_first(evt->cpumask);
 206        unsigned int next = (unsigned int)delta;
 207
 208        sparc_config.load_profile_irq(cpu, next);
 209        return 0;
 210}
 211
 212void register_percpu_ce(int cpu)
 213{
 214        struct clock_event_device *ce = &per_cpu(sparc32_clockevent, cpu);
 215        unsigned int features = CLOCK_EVT_FEAT_PERIODIC;
 216
 217        if (sparc_config.features & FEAT_L14_ONESHOT)
 218                features |= CLOCK_EVT_FEAT_ONESHOT;
 219
 220        ce->name           = "percpu_ce";
 221        ce->rating         = 200;
 222        ce->features       = features;
 223        ce->set_state_shutdown = percpu_ce_shutdown;
 224        ce->set_state_periodic = percpu_ce_set_periodic;
 225        ce->set_state_oneshot = percpu_ce_shutdown;
 226        ce->set_next_event = percpu_ce_set_next_event;
 227        ce->cpumask        = cpumask_of(cpu);
 228        ce->shift          = 32;
 229        ce->mult           = div_sc(sparc_config.clock_rate, NSEC_PER_SEC,
 230                                    ce->shift);
 231        ce->max_delta_ns   = clockevent_delta2ns(sparc_config.clock_rate, ce);
 232        ce->max_delta_ticks = (unsigned long)sparc_config.clock_rate;
 233        ce->min_delta_ns   = clockevent_delta2ns(100, ce);
 234        ce->min_delta_ticks = 100;
 235
 236        clockevents_register_device(ce);
 237}
 238#endif
 239
 240static unsigned char mostek_read_byte(struct device *dev, u32 ofs)
 241{
 242        struct platform_device *pdev = to_platform_device(dev);
 243        struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 244
 245        return readb(pdata->ioaddr + ofs);
 246}
 247
 248static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
 249{
 250        struct platform_device *pdev = to_platform_device(dev);
 251        struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 252
 253        writeb(val, pdata->ioaddr + ofs);
 254}
 255
 256static struct m48t59_plat_data m48t59_data = {
 257        .read_byte = mostek_read_byte,
 258        .write_byte = mostek_write_byte,
 259};
 260
 261/* resource is set at runtime */
 262static struct platform_device m48t59_rtc = {
 263        .name           = "rtc-m48t59",
 264        .id             = 0,
 265        .num_resources  = 1,
 266        .dev    = {
 267                .platform_data = &m48t59_data,
 268        },
 269};
 270
 271static int clock_probe(struct platform_device *op)
 272{
 273        struct device_node *dp = op->dev.of_node;
 274        const char *model = of_get_property(dp, "model", NULL);
 275
 276        if (!model)
 277                return -ENODEV;
 278
 279        /* Only the primary RTC has an address property */
 280        if (!of_find_property(dp, "address", NULL))
 281                return -ENODEV;
 282
 283        m48t59_rtc.resource = &op->resource[0];
 284        if (!strcmp(model, "mk48t02")) {
 285                /* Map the clock register io area read-only */
 286                m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
 287                                                2048, "rtc-m48t59");
 288                m48t59_data.type = M48T59RTC_TYPE_M48T02;
 289        } else if (!strcmp(model, "mk48t08")) {
 290                m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
 291                                                8192, "rtc-m48t59");
 292                m48t59_data.type = M48T59RTC_TYPE_M48T08;
 293        } else
 294                return -ENODEV;
 295
 296        if (platform_device_register(&m48t59_rtc) < 0)
 297                printk(KERN_ERR "Registering RTC device failed\n");
 298
 299        return 0;
 300}
 301
 302static const struct of_device_id clock_match[] = {
 303        {
 304                .name = "eeprom",
 305        },
 306        {},
 307};
 308
 309static struct platform_driver clock_driver = {
 310        .probe          = clock_probe,
 311        .driver = {
 312                .name = "rtc",
 313                .of_match_table = clock_match,
 314        },
 315};
 316
 317
 318/* Probe for the mostek real time clock chip. */
 319static int __init clock_init(void)
 320{
 321        return platform_driver_register(&clock_driver);
 322}
 323/* Must be after subsys_initcall() so that busses are probed.  Must
 324 * be before device_initcall() because things like the RTC driver
 325 * need to see the clock registers.
 326 */
 327fs_initcall(clock_init);
 328
 329static void __init sparc32_late_time_init(void)
 330{
 331        if (sparc_config.features & FEAT_L10_CLOCKEVENT)
 332                setup_timer_ce();
 333        if (sparc_config.features & FEAT_L10_CLOCKSOURCE)
 334                setup_timer_cs();
 335#ifdef CONFIG_SMP
 336        register_percpu_ce(smp_processor_id());
 337#endif
 338}
 339
 340static void __init sbus_time_init(void)
 341{
 342        sparc_config.get_cycles_offset = sbus_cycles_offset;
 343        sparc_config.init_timers();
 344}
 345
 346void __init time_init(void)
 347{
 348        sparc_config.features = 0;
 349        late_time_init = sparc32_late_time_init;
 350
 351        if (pcic_present())
 352                pci_time_init();
 353        else
 354                sbus_time_init();
 355}
 356
 357