--- /dev/null
+/*
+ * arch/ubicom32/kernel/time.c
+ * Initialize the timer list and start the appropriate timers.
+ *
+ * (C) Copyright 2009, Ubicom, Inc.
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ *
+ * This file is part of the Ubicom32 Linux Kernel Port.
+ *
+ * The Ubicom32 Linux Kernel Port is free software: you can redistribute
+ * it and/or modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * The Ubicom32 Linux Kernel Port is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the Ubicom32 Linux Kernel Port. If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Ubicom32 implementation derived from (with many thanks):
+ * arch/m68knommu
+ * arch/blackfin
+ * arch/parisc
+ */
+
+#include <linux/profile.h>
+#include <linux/smp.h>
+#include <asm/ip5000.h>
+#include <asm/machdep.h>
+
+/*
+ * A bitmap of the timers on the processor indicates
+ * that the timer is free or in-use.
+ */
+static unsigned int timers;
+
+/*
+ * timer_set()
+ * Init the specified compare register to go off <n> cycles from now.
+ */
+void timer_set(int timervector, unsigned int cycles)
+{
+ int idx = UBICOM32_VECTOR_TO_TIMER_INDEX(timervector);
+ UBICOM32_IO_TIMER->syscom[idx] =
+ UBICOM32_IO_TIMER->sysval + cycles;
+ ldsr_enable_vector(timervector);
+}
+
+/*
+ * timer_reset()
+ * Set/reset the timer to go off again.
+ *
+ * Because sysval is a continuous timer, this function is able
+ * to ensure that we do not have clock sku by using the previous
+ * value in syscom to set the next value for syscom.
+ *
+ * Returns the number of ticks that transpired since the last event.
+ */
+int timer_reset(int timervector, unsigned int cycles)
+{
+ /*
+ * Reset the timer in the LDSR thread to go off appropriately.
+ *
+ * Use the previous value of the timer to calculate the new stop
+ * time. This allows us to account for it taking an
+ * indeterminate amount of time to get here.
+ */
+ const int timer_index = UBICOM32_VECTOR_TO_TIMER_INDEX(timervector);
+ unsigned int prev = UBICOM32_IO_TIMER->syscom[timer_index];
+ unsigned int next = prev + cycles;
+ int scratchpad3;
+ int diff;
+ int ticks = 1;
+
+ /*
+ * If the difference is negative, we have missed at least one
+ * timer tick.
+ *
+ * TODO: Decide if we want to "ignore" time (as done below) or
+ * if we want to process time (unevenly) by calling timer_tick()
+ * lost_ticks times.
+ */
+ while (1) {
+ /*
+ * Set our future time first.
+ */
+ UBICOM32_IO_TIMER->syscom[timer_index] = next;
+
+ /*
+ * Then check if we are really set time in the futrue.
+ */
+ diff = (int)next - (int)UBICOM32_IO_TIMER->sysval;
+ if (diff >= 0) {
+ break;
+ }
+
+ /*
+ * Oops, we are too slow. Playing catch up.
+ *
+ * If the debugger is connected the there is a good
+ * chance that we lost time because we were in a
+ * break-point, so in this case we do not print out
+ * diagnostics.
+ */
+ asm volatile ("move.4 %0, scratchpad3"
+ : "=r" (scratchpad3));
+ if ((scratchpad3 & 0x1) == 0) {
+ /*
+ * No debugger attached, print to the console
+ */
+ printk(KERN_EMERG "diff: %d, timer has lost %u "
+ "ticks [rounded up]\n",
+ -diff,
+ (unsigned int)((-diff + cycles - 1) / cycles));
+ }
+
+ do {
+ next += cycles;
+ diff = (int)next - (int)UBICOM32_IO_TIMER->sysval;
+ ticks++;
+ } while (diff < 0);
+ }
+ return ticks;
+}
+
+/*
+ * sched_clock()
+ * Returns current time in nano-second units.
+ *
+ * Notes:
+ * 1) This is an override for the weak alias in
+ * kernel/sched_clock.c.
+ * 2) Do not use xtime_lock as this function is
+ * sometimes called with xtime_lock held.
+ * 3) We use a retry algorithm to ensure that
+ * we get a consistent value.
+ * 4) sched_clock must be overwritten if IRQ tracing
+ * is enabled because the default implementation uses
+ * the xtime_lock sequence while holding xtime_lock.
+ */
+unsigned long long sched_clock(void)
+{
+ unsigned long long my_jiffies;
+ unsigned long jiffies_top;
+ unsigned long jiffies_bottom;
+
+ do {
+ jiffies_top = jiffies_64 >> 32;
+ jiffies_bottom = jiffies_64 & 0xffffffff;
+ } while (unlikely(jiffies_top != (unsigned long)(jiffies_64 >> 32)));
+
+ my_jiffies = ((unsigned long long)jiffies_top << 32) | (jiffies_bottom);
+ return (my_jiffies - INITIAL_JIFFIES) * (NSEC_PER_SEC / HZ);
+}
+
+/*
+ * timer_free()
+ * Free a hardware timer.
+ */
+void timer_free(int interrupt)
+{
+ unsigned int bit = interrupt - TIMER_INT(0);
+
+ /*
+ * The timer had not been allocated.
+ */
+ BUG_ON(timers & (1 << bit));
+ timers |= (1 << bit);
+}
+
+/*
+ * timer_alloc()
+ * Allocate a hardware timer.
+ */
+int timer_alloc(void)
+{
+ unsigned int bit = find_first_bit((unsigned long *)&timers, 32);
+ if (!bit) {
+ printk(KERN_WARNING "no more free timers\n");
+ return -1;
+ }
+
+ timers &= ~(1 << bit);
+ return bit + TIMER_INT(0);
+}
+
+/*
+ * time_init()
+ * Time init function.
+ */
+void time_init(void)
+{
+ /*
+ * Find the processor node and determine what timers are
+ * available for us.
+ */
+ timers = processor_timers();
+ if (timers == 0) {
+ printk(KERN_WARNING "no timers are available for Linux\n");
+ return;
+ }
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+ timer_device_init();
+#else
+ timer_tick_init();
+#endif
+}
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