Changeset 615 for GPL/branches/uniaud32-next/lib32/timer.c

Timestamp:

Jan 1, 2021, 5:31:48 AM (5 years ago)

Author:

Paul Smedley

Message:

Add source for uniaud32 based on code from linux kernel 5.4.86

Location:

GPL/branches/uniaud32-next

Files:

• . (copied) (copied from GPL/branches/uniaud32-linux-3.2.102 )
• lib32/timer.c (modified) (2 diffs)

GPL/branches/uniaud32-next/lib32/timer.c

@@ -30 +30 @@
 #include <asm/io.h>
 #include <linux/time.h>
+#include <linux/math64.h>
+#include <linux/clocksource.h>
 
 #define LINUX
@@ -140 +142 @@
 //******************************************************************************
 //******************************************************************************
+
+/**
+ * ns_to_timespec - Convert nanoseconds to timespec
+ * @nsec:       the nanoseconds value to be converted
+ *
+ * Returns the timespec representation of the nsec parameter.
+ */
+struct timespec ns_to_timespec(const s64 nsec)
+{
+        struct timespec ts;
+        s32 rem;
+
+        if (!nsec) {
+                ts.tv_sec = 0;
+                ts.tv_nsec = 0;
+                return ts;
+        }
+
+        ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
+        if (unlikely(rem < 0)) {
+                ts.tv_sec--;
+                rem += NSEC_PER_SEC;
+        }
+        ts.tv_nsec = rem;
+
+        return ts;
+}
+
+
+//******************************************************************************
+//******************************************************************************
+
+void timecounter_init(struct timecounter *tc,
+                      const struct cyclecounter *cc,
+                      u64 start_tstamp)
+{
+        tc->cc = cc;
+        tc->cycle_last = cc->read(cc);
+        tc->nsec = start_tstamp;
+}
+
+/**
+ * timecounter_read_delta - get nanoseconds since last call of this function
+ * @tc:         Pointer to time counter
+ *
+ * When the underlying cycle counter runs over, this will be handled
+ * correctly as long as it does not run over more than once between
+ * calls.
+ *
+ * The first call to this function for a new time counter initializes
+ * the time tracking and returns an undefined result.
+ */
+static u64 timecounter_read_delta(struct timecounter *tc)
+{
+        cycle_t cycle_now, cycle_delta;
+        u64 ns_offset;
+
+        /* read cycle counter: */
+        cycle_now = tc->cc->read(tc->cc);
+
+        /* calculate the delta since the last timecounter_read_delta(): */
+        cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;
+
+        /* convert to nanoseconds: */
+        ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta);
+
+        /* update time stamp of timecounter_read_delta() call: */
+        tc->cycle_last = cycle_now;
+
+        return ns_offset;
+}
+
+u64 timecounter_read(struct timecounter *tc)
+{
+        u64 nsec;
+
+        /* increment time by nanoseconds since last call */
+        nsec = timecounter_read_delta(tc);
+        nsec += tc->nsec;
+        tc->nsec = nsec;
+
+        return nsec;
+}
+
+/**
+ * set_normalized_timespec - set timespec sec and nsec parts and normalize
+ *
+ * @ts:         pointer to timespec variable to be set
+ * @sec:        seconds to set
+ * @nsec:       nanoseconds to set
+ *
+ * Set seconds and nanoseconds field of a timespec variable and
+ * normalize to the timespec storage format
+ *
+ * Note: The tv_nsec part is always in the range of
+ *      0 <= tv_nsec < NSEC_PER_SEC
+ * For negative values only the tv_sec field is negative !
+ */
+void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
+{
+        while (nsec >= NSEC_PER_SEC) {
+                /*
+                 * The following asm() prevents the compiler from
+                 * optimising this loop into a modulo operation. See
+                 * also __iter_div_u64_rem() in include/linux/time.h
+                 */
+//              asm("" : "+rm"(nsec));
+                nsec -= NSEC_PER_SEC;
+                ++sec;
+        }
+        while (nsec < 0) {
+//              asm("" : "+rm"(nsec));
+                nsec += NSEC_PER_SEC;
+                --sec;
+        }
+        ts->tv_sec = sec;
+        ts->tv_nsec = nsec;
+}