[PARISC] GENERIC_TIME patchset for parisc

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

2 files changed, 28 insertions, 110 deletions

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 848a67a024b..e18eeecae85 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -50,6 +50,10 @@ config GENERIC_CALIBRATE_DELAY
         bool
         default y
 
+config GENERIC_TIME
+        bool
+        default y
+
 config TIME_LOW_RES
         bool
         depends on SMP
diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index bad7d1eb62b..e47e27cea42 100644
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/profile.h>
+#include <linux/clocksource.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -172,121 +173,23 @@ unsigned long profile_pc(struct pt_regs *regs)
 EXPORT_SYMBOL(profile_pc);
 
 
-/*
- * Return the number of micro-seconds that elapsed since the last
- * update to wall time (aka xtime).  The xtime_lock
- * must be at least read-locked when calling this routine.
- */
-static inline unsigned long gettimeoffset (void)
-{
-#ifndef CONFIG_SMP
-        /*
-         * FIXME: This won't work on smp because jiffies are updated by cpu 0.
-         *    Once parisc-linux learns the cr16 difference between processors,
-         *    this could be made to work.
-         */
-        unsigned long now;
-        unsigned long prev_tick;
-        unsigned long next_tick;
-        unsigned long elapsed_cycles;
-        unsigned long usec;
-        unsigned long cpuid = smp_processor_id();
-        unsigned long cpt = clocktick;
+/* clock source code */
 
-        next_tick = cpu_data[cpuid].it_value;
-        now = mfctl(16);        /* Read the hardware interval timer.  */
-
-        prev_tick = next_tick - cpt;
-
-        /* Assume Scenario 1: "now" is later than prev_tick.  */
-        elapsed_cycles = now - prev_tick;
-
-/* aproximate HZ with shifts. Intended math is "(elapsed/clocktick) > HZ" */
-#if HZ == 1000
-        if (elapsed_cycles > (cpt << 10) )
-#elif HZ == 250
-        if (elapsed_cycles > (cpt << 8) )
-#elif HZ == 100
-        if (elapsed_cycles > (cpt << 7) )
-#else
-#warn WTF is HZ set to anyway?
-        if (elapsed_cycles > (HZ * cpt) )
-#endif
-        {
-                /* Scenario 3: clock ticks are missing. */
-                printk (KERN_CRIT "gettimeoffset(CPU %ld): missing %ld ticks!"
-                        " cycles %lX prev/now/next %lX/%lX/%lX  clock %lX\n",
-                        cpuid, elapsed_cycles / cpt,
-                        elapsed_cycles, prev_tick, now, next_tick, cpt);
-        }
-
-        /* FIXME: Can we improve the precision? Not with PAGE0. */
-        usec = (elapsed_cycles * 10000) / PAGE0->mem_10msec;
-        return usec;
-#else
-        return 0;
-#endif
-}
-
-void
-do_gettimeofday (struct timeval *tv)
+static cycle_t read_cr16(void)
 {
-        unsigned long flags, seq, usec, sec;
-
-        /* Hold xtime_lock and adjust timeval.  */
-        do {
-                seq = read_seqbegin_irqsave(&xtime_lock, flags);
-                usec = gettimeoffset();
-                sec = xtime.tv_sec;
-                usec += (xtime.tv_nsec / 1000);
-        } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
-        /* Move adjusted usec's into sec's.  */
-        while (usec >= USEC_PER_SEC) {
-                usec -= USEC_PER_SEC;
-                ++sec;
-        }
-
-        /* Return adjusted result.  */
-        tv->tv_sec = sec;
-        tv->tv_usec = usec;
+        return get_cycles();
 }
 
-EXPORT_SYMBOL(do_gettimeofday);
-
-int
-do_settimeofday (struct timespec *tv)
-{
-        time_t wtm_sec, sec = tv->tv_sec;
-        long wtm_nsec, nsec = tv->tv_nsec;
-
-        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-                return -EINVAL;
-
-        write_seqlock_irq(&xtime_lock);
-        {
-                /*
-                 * This is revolting. We need to set "xtime"
-                 * correctly. However, the value in this location is
-                 * the value at the most recent update of wall time.
-                 * Discover what correction gettimeofday would have
-                 * done, and then undo it!
-                 */
-                nsec -= gettimeoffset() * 1000;
+static struct clocksource clocksource_cr16 = {
+        .name                   = "cr16",
+        .rating                 = 300,
+        .read                   = read_cr16,
+        .mask                   = CLOCKSOURCE_MASK(BITS_PER_LONG),
+        .mult                   = 0, /* to be set */
+        .shift                  = 22,
+        .is_continuous          = 1,
+};
 
-                wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-                wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
-                set_normalized_timespec(&xtime, sec, nsec);
-                set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
-                ntp_clear();
-        }
-        write_sequnlock_irq(&xtime_lock);
-        clock_was_set();
-        return 0;
-}
-EXPORT_SYMBOL(do_settimeofday);
 
 /*
  * XXX: We can do better than this.
@@ -312,11 +215,22 @@ void __init start_cpu_itimer(void)
 void __init time_init(void)
 {
         static struct pdc_tod tod_data;
+        unsigned long current_cr16_khz;
 
         clocktick = (100 * PAGE0->mem_10msec) / HZ;
 
         start_cpu_itimer();     /* get CPU 0 started */
 
+        /* register at clocksource framework */
+        current_cr16_khz = PAGE0->mem_10msec/10;  /* kHz */
+        clocksource_cr16.mult = clocksource_khz2mult(current_cr16_khz,
+                                                clocksource_cr16.shift);
+        /* lower the rating if we already know its unstable: */
+        if (num_online_cpus()>1)
+                clocksource_cr16.rating = 200;
+
+        clocksource_register(&clocksource_cr16);
+
         if (pdc_tod_read(&tod_data) == 0) {
                 unsigned long flags;