--- /dev/null
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2015 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#define NSEC_PER_SEC 1000000000L
+
+/**
+ * Structure to hold the parameters of a running cycle counter to assist
+ * in converting cycles to nanoseconds.
+ */
+struct rte_timecounter {
+ /** Last cycle counter value read. */
+ uint64_t cycle_last;
+ /** Nanoseconds count. */
+ uint64_t nsec;
+ /** Bitmask separating nanosecond and sub-nanoseconds. */
+ uint64_t nsec_mask;
+ /** Sub-nanoseconds count. */
+ uint64_t nsec_frac;
+ /** Bitmask for two's complement substraction of non-64 bit counters. */
+ uint64_t cc_mask;
+ /** Cycle to nanosecond divisor (power of two). */
+ uint32_t cc_shift;
+};
+
+/**
+ * Converts cyclecounter cycles to nanoseconds.
+ */
+static inline uint64_t
+rte_cyclecounter_cycles_to_ns(struct rte_timecounter *tc, uint64_t cycles)
+{
+ uint64_t ns;
+
+ /* Add fractional nanoseconds. */
+ ns = cycles + tc->nsec_frac;
+ tc->nsec_frac = ns & tc->nsec_mask;
+
+ /* Shift to get only nanoseconds. */
+ return ns >> tc->cc_shift;
+}
+
+/**
+ * Update the internal nanosecond count in the structure.
+ */
+static inline uint64_t
+rte_timecounter_update(struct rte_timecounter *tc, uint64_t cycle_now)
+{
+ uint64_t cycle_delta, ns_offset;
+
+ /* Calculate the delta since the last call. */
+ if (tc->cycle_last <= cycle_now)
+ cycle_delta = (cycle_now - tc->cycle_last) & tc->cc_mask;
+ else
+ /* Handle cycle counts that have wrapped around . */
+ cycle_delta = (~(tc->cycle_last - cycle_now) & tc->cc_mask) + 1;
+
+ /* Convert to nanoseconds. */
+ ns_offset = rte_cyclecounter_cycles_to_ns(tc, cycle_delta);
+
+ /* Store current cycle counter for next call. */
+ tc->cycle_last = cycle_now;
+
+ /* Update the nanosecond count. */
+ tc->nsec += ns_offset;
+
+ return tc->nsec;
+}
+
+/**
+ * Convert from timespec structure into nanosecond units.
+ */
+static inline uint64_t
+rte_timespec_to_ns(const struct timespec *ts)
+{
+ return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
+}
+
+/**
+ * Convert from nanosecond units into timespec structure.
+ */
+static inline struct timespec
+rte_ns_to_timespec(uint64_t nsec)
+{
+ struct timespec ts = {0, 0};
+
+ if (nsec == 0)
+ return ts;
+
+ ts.tv_sec = nsec / NSEC_PER_SEC;
+ ts.tv_nsec = nsec % NSEC_PER_SEC;
+
+ return ts;
+}