[RFC,v3,1/3] ethdev: add frequency adjustment API

diff --git a/lib/ethdev/ethdev_driver.h b/lib/ethdev/ethdev_driver.h
index 2c9d615..b6fce64 100644
--- a/lib/ethdev/ethdev_driver.h
+++ b/lib/ethdev/ethdev_driver.h
@@ -633,6 +633,9 @@  typedef int (*eth_timesync_read_tx_timestamp_t)(struct rte_eth_dev *dev,
 /** @internal Function used to adjust the device clock. */
 typedef int (*eth_timesync_adjust_time)(struct rte_eth_dev *dev, int64_t);
 
+/** @internal Function used to adjust the clock increment rate. */
+typedef int (*eth_timesync_adjust_fine)(struct rte_eth_dev *dev, int64_t);
+
 /** @internal Function used to get time from the device clock. */
 typedef int (*eth_timesync_read_time)(struct rte_eth_dev *dev,
 				      struct timespec *timestamp);
@@ -1344,6 +1347,8 @@  struct eth_dev_ops {
 	eth_timesync_read_tx_timestamp_t timesync_read_tx_timestamp;
 	/** Adjust the device clock */
 	eth_timesync_adjust_time   timesync_adjust_time;
+	/** Adjust the clock increment rate */
+	eth_timesync_adjust_fine   timesync_adjust_fine;
 	/** Get the device clock time */
 	eth_timesync_read_time     timesync_read_time;
 	/** Set the device clock time */
diff --git a/lib/ethdev/ethdev_trace.h b/lib/ethdev/ethdev_trace.h
index 3dc7d02..1b10aab 100644
--- a/lib/ethdev/ethdev_trace.h
+++ b/lib/ethdev/ethdev_trace.h
@@ -2196,6 +2196,15 @@  RTE_TRACE_POINT_FP(
 	rte_trace_point_emit_int(ret);
 )
 
+/* Called in loop in examples/ptpclient */
+RTE_TRACE_POINT_FP(
+	rte_eth_trace_timesync_adjust_fine,
+	RTE_TRACE_POINT_ARGS(uint16_t port_id, int64_t scaled_ppm, int ret),
+	rte_trace_point_emit_u16(port_id);
+	rte_trace_point_emit_i64(scaled_ppm);
+	rte_trace_point_emit_int(ret);
+)
+
 /* Called in loop in app/test-flow-perf */
 RTE_TRACE_POINT_FP(
 	rte_flow_trace_create,
diff --git a/lib/ethdev/ethdev_trace_points.c b/lib/ethdev/ethdev_trace_points.c
index 61010ca..b7ac391 100644
--- a/lib/ethdev/ethdev_trace_points.c
+++ b/lib/ethdev/ethdev_trace_points.c
@@ -406,6 +406,9 @@  RTE_TRACE_POINT_REGISTER(rte_eth_trace_timesync_read_tx_timestamp,
 RTE_TRACE_POINT_REGISTER(rte_eth_trace_timesync_adjust_time,
 	lib.ethdev.timesync_adjust_time)
 
+RTE_TRACE_POINT_REGISTER(rte_eth_trace_timesync_adjust_fine,
+	lib.ethdev.timesync_adjust_fine)
+
 RTE_TRACE_POINT_REGISTER(rte_eth_trace_timesync_read_time,
 	lib.ethdev.timesync_read_time)
 
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 4d03255..17be7c8 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -6017,6 +6017,25 @@  rte_eth_timesync_adjust_time(uint16_t port_id, int64_t delta)
 }
 
 int
+rte_eth_timesync_adjust_fine(uint16_t port_id, int64_t scaled_ppm)
+{
+	struct rte_eth_dev *dev;
+	int ret;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+	dev = &rte_eth_devices[port_id];
+
+	if (*dev->dev_ops->timesync_adjust_fine == NULL)
+		return -ENOTSUP;
+	ret = eth_err(port_id, (*dev->dev_ops->timesync_adjust_fine)(dev,
+								scaled_ppm));
+
+	rte_eth_trace_timesync_adjust_fine(port_id, scaled_ppm, ret);
+
+	return ret;
+}
+
+int
 rte_eth_timesync_read_time(uint16_t port_id, struct timespec *timestamp)
 {
 	struct rte_eth_dev *dev;
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index 99fe9e2..a743d83 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -5102,6 +5102,44 @@  int rte_eth_timesync_read_tx_timestamp(uint16_t port_id,
 int rte_eth_timesync_adjust_time(uint16_t port_id, int64_t delta);
 
 /**
+ * Adjust the frequency of the PHC cycle counter by the indicated amount
+ * from the base frequency.
+ *
+ * This function is used to do hardware timestamp adjustment in fine
+ * granularity. It can be used in conjunction with rte_eth_timesync_adjust_time
+ * to do more precise time control.
+ *
+ * E.g, below is a simple usage:
+ * if master offset > master offset threshold
+ *	do rte_eth_timesync_adjust_time;
+ * else
+ *	do rte_eth_timesync_adjust_fine;
+ *
+ * The user can apply a control algorithm to leverage these two APIs, one
+ * example is in dpdk-ptpclient.
+ *
+ * This API is implemented with the below basic logic:
+ *   - Determine a base frequency value
+ *   - Multiply this by the abs() of the requested adjustment, then divide by
+ *     the appropriate divisor (65536 billion).
+ *   - Add or subtract this difference from the base frequency to calculate a
+ *     new adjustment.
+ *
+ * @param port_id
+ *  The port identifier of the Ethernet device.
+ * @param scaled_ppm
+ *  Desired frequency change in scaled parts per million. Scaled parts per
+ *  million is ppm with a 16-bit binary fractional field.
+ *
+ * @return
+ *   - 0: Success.
+ *   - -ENODEV: The port ID is invalid.
+ *   - -EIO: if device is removed.
+ *   - -ENOTSUP: The function is not supported by the Ethernet driver.
+ */
+int rte_eth_timesync_adjust_fine(uint16_t port_id, int64_t scaled_ppm);
+
+/**
  * Read the time from the timesync clock on an Ethernet device.
  *
  * This is usually used in conjunction with other Ethdev timesync functions to