v4.19.13 snapshot.
diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
new file mode 100644
index 0000000..a1e772f
--- /dev/null
+++ b/arch/parisc/kernel/time.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/arch/parisc/kernel/time.c
+ *
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ * Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King
+ * Copyright (C) 1999 SuSE GmbH, (Philipp Rumpf, prumpf@tux.org)
+ *
+ * 1994-07-02 Alan Modra
+ * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
+ * 1998-12-20 Updated NTP code according to technical memorandum Jan '96
+ * "A Kernel Model for Precision Timekeeping" by Dave Mills
+ */
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/sched_clock.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/profile.h>
+#include <linux/clocksource.h>
+#include <linux/platform_device.h>
+#include <linux/ftrace.h>
+
+#include <linux/uaccess.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/page.h>
+#include <asm/param.h>
+#include <asm/pdc.h>
+#include <asm/led.h>
+
+#include <linux/timex.h>
+
+static unsigned long clocktick __read_mostly; /* timer cycles per tick */
+
+/*
+ * We keep time on PA-RISC Linux by using the Interval Timer which is
+ * a pair of registers; one is read-only and one is write-only; both
+ * accessed through CR16. The read-only register is 32 or 64 bits wide,
+ * and increments by 1 every CPU clock tick. The architecture only
+ * guarantees us a rate between 0.5 and 2, but all implementations use a
+ * rate of 1. The write-only register is 32-bits wide. When the lowest
+ * 32 bits of the read-only register compare equal to the write-only
+ * register, it raises a maskable external interrupt. Each processor has
+ * an Interval Timer of its own and they are not synchronised.
+ *
+ * We want to generate an interrupt every 1/HZ seconds. So we program
+ * CR16 to interrupt every @clocktick cycles. The it_value in cpu_data
+ * is programmed with the intended time of the next tick. We can be
+ * held off for an arbitrarily long period of time by interrupts being
+ * disabled, so we may miss one or more ticks.
+ */
+irqreturn_t __irq_entry timer_interrupt(int irq, void *dev_id)
+{
+ unsigned long now;
+ unsigned long next_tick;
+ unsigned long ticks_elapsed = 0;
+ unsigned int cpu = smp_processor_id();
+ struct cpuinfo_parisc *cpuinfo = &per_cpu(cpu_data, cpu);
+
+ /* gcc can optimize for "read-only" case with a local clocktick */
+ unsigned long cpt = clocktick;
+
+ profile_tick(CPU_PROFILING);
+
+ /* Initialize next_tick to the old expected tick time. */
+ next_tick = cpuinfo->it_value;
+
+ /* Calculate how many ticks have elapsed. */
+ now = mfctl(16);
+ do {
+ ++ticks_elapsed;
+ next_tick += cpt;
+ } while (next_tick - now > cpt);
+
+ /* Store (in CR16 cycles) up to when we are accounting right now. */
+ cpuinfo->it_value = next_tick;
+
+ /* Go do system house keeping. */
+ if (cpu == 0)
+ xtime_update(ticks_elapsed);
+
+ update_process_times(user_mode(get_irq_regs()));
+
+ /* Skip clockticks on purpose if we know we would miss those.
+ * The new CR16 must be "later" than current CR16 otherwise
+ * itimer would not fire until CR16 wrapped - e.g 4 seconds
+ * later on a 1Ghz processor. We'll account for the missed
+ * ticks on the next timer interrupt.
+ * We want IT to fire modulo clocktick even if we miss/skip some.
+ * But those interrupts don't in fact get delivered that regularly.
+ *
+ * "next_tick - now" will always give the difference regardless
+ * if one or the other wrapped. If "now" is "bigger" we'll end up
+ * with a very large unsigned number.
+ */
+ now = mfctl(16);
+ while (next_tick - now > cpt)
+ next_tick += cpt;
+
+ /* Program the IT when to deliver the next interrupt.
+ * Only bottom 32-bits of next_tick are writable in CR16!
+ * Timer interrupt will be delivered at least a few hundred cycles
+ * after the IT fires, so if we are too close (<= 8000 cycles) to the
+ * next cycle, simply skip it.
+ */
+ if (next_tick - now <= 8000)
+ next_tick += cpt;
+ mtctl(next_tick, 16);
+
+ return IRQ_HANDLED;
+}
+
+
+unsigned long profile_pc(struct pt_regs *regs)
+{
+ unsigned long pc = instruction_pointer(regs);
+
+ if (regs->gr[0] & PSW_N)
+ pc -= 4;
+
+#ifdef CONFIG_SMP
+ if (in_lock_functions(pc))
+ pc = regs->gr[2];
+#endif
+
+ return pc;
+}
+EXPORT_SYMBOL(profile_pc);
+
+
+/* clock source code */
+
+static u64 notrace read_cr16(struct clocksource *cs)
+{
+ return get_cycles();
+}
+
+static struct clocksource clocksource_cr16 = {
+ .name = "cr16",
+ .rating = 300,
+ .read = read_cr16,
+ .mask = CLOCKSOURCE_MASK(BITS_PER_LONG),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+void __init start_cpu_itimer(void)
+{
+ unsigned int cpu = smp_processor_id();
+ unsigned long next_tick = mfctl(16) + clocktick;
+
+ mtctl(next_tick, 16); /* kick off Interval Timer (CR16) */
+
+ per_cpu(cpu_data, cpu).it_value = next_tick;
+}
+
+#if IS_ENABLED(CONFIG_RTC_DRV_GENERIC)
+static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
+{
+ struct pdc_tod tod_data;
+
+ memset(tm, 0, sizeof(*tm));
+ if (pdc_tod_read(&tod_data) < 0)
+ return -EOPNOTSUPP;
+
+ /* we treat tod_sec as unsigned, so this can work until year 2106 */
+ rtc_time64_to_tm(tod_data.tod_sec, tm);
+ return 0;
+}
+
+static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
+{
+ time64_t secs = rtc_tm_to_time64(tm);
+
+ if (pdc_tod_set(secs, 0) < 0)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
+static const struct rtc_class_ops rtc_generic_ops = {
+ .read_time = rtc_generic_get_time,
+ .set_time = rtc_generic_set_time,
+};
+
+static int __init rtc_init(void)
+{
+ struct platform_device *pdev;
+
+ pdev = platform_device_register_data(NULL, "rtc-generic", -1,
+ &rtc_generic_ops,
+ sizeof(rtc_generic_ops));
+
+ return PTR_ERR_OR_ZERO(pdev);
+}
+device_initcall(rtc_init);
+#endif
+
+void read_persistent_clock64(struct timespec64 *ts)
+{
+ static struct pdc_tod tod_data;
+ if (pdc_tod_read(&tod_data) == 0) {
+ ts->tv_sec = tod_data.tod_sec;
+ ts->tv_nsec = tod_data.tod_usec * 1000;
+ } else {
+ printk(KERN_ERR "Error reading tod clock\n");
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
+ }
+}
+
+
+static u64 notrace read_cr16_sched_clock(void)
+{
+ return get_cycles();
+}
+
+
+/*
+ * timer interrupt and sched_clock() initialization
+ */
+
+void __init time_init(void)
+{
+ unsigned long cr16_hz;
+
+ clocktick = (100 * PAGE0->mem_10msec) / HZ;
+ start_cpu_itimer(); /* get CPU 0 started */
+
+ cr16_hz = 100 * PAGE0->mem_10msec; /* Hz */
+
+ /* register as sched_clock source */
+ sched_clock_register(read_cr16_sched_clock, BITS_PER_LONG, cr16_hz);
+}
+
+static int __init init_cr16_clocksource(void)
+{
+ /*
+ * The cr16 interval timers are not syncronized across CPUs on
+ * different sockets, so mark them unstable and lower rating on
+ * multi-socket SMP systems.
+ */
+ if (num_online_cpus() > 1 && !running_on_qemu) {
+ int cpu;
+ unsigned long cpu0_loc;
+ cpu0_loc = per_cpu(cpu_data, 0).cpu_loc;
+
+ for_each_online_cpu(cpu) {
+ if (cpu == 0)
+ continue;
+ if ((cpu0_loc != 0) &&
+ (cpu0_loc == per_cpu(cpu_data, cpu).cpu_loc))
+ continue;
+
+ clocksource_cr16.name = "cr16_unstable";
+ clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
+ clocksource_cr16.rating = 0;
+ break;
+ }
+ }
+
+ /* XXX: We may want to mark sched_clock stable here if cr16 clocks are
+ * in sync:
+ * (clocksource_cr16.flags == CLOCK_SOURCE_IS_CONTINUOUS) */
+
+ /* register at clocksource framework */
+ clocksource_register_hz(&clocksource_cr16,
+ 100 * PAGE0->mem_10msec);
+
+ return 0;
+}
+
+device_initcall(init_cr16_clocksource);