[PATCH] examples/ptpclient: revert add frequency adjustment

[Mingjin Ye <mingjinx.ye@intel.com>]

This commit references GPL-licensed code and therefore cannot be applied
to the DPDK.

Therefore the following commit was reverted accordingly.

Fixes: 6d55af611fd5 ("examples/ptpclient: add frequency adjustment")

By resuming this commit, the basic functionality (PMD support for
high-precision clocks) will not be affected, but its accuracy will be
reduced to the microsecond level.

Fixes: 6d55af611fd5 ("examples/ptpclient: add frequency adjustment")

Signed-off-by: Mingjin Ye <mingjinx.ye@intel.com>
---
 doc/guides/sample_app_ug/ptpclient.rst |  17 +-
 examples/ptpclient/ptpclient.c         | 302 ++-----------------------
 2 files changed, 25 insertions(+), 294 deletions(-)

diff --git a/doc/guides/sample_app_ug/ptpclient.rst b/doc/guides/sample_app_ug/ptpclient.rst
index e03a8452d8..38f0479a0f 100644
--- a/doc/guides/sample_app_ug/ptpclient.rst
+++ b/doc/guides/sample_app_ug/ptpclient.rst
@@ -50,12 +50,6 @@ The adjustment for time receiver can be represented as:
 If the command line parameter ``-T 1`` is used the application also
 synchronizes the PTP PHC clock with the Linux kernel clock.
 
-If the command line parameter ``-c 1`` is used,
-the application will also use the servo of the local clock.
-Only one type of servo is currently implemented, the PI controller.
-Default 0 (not used).
-
-
 Compiling the Application
 -------------------------
 
@@ -71,7 +65,7 @@ To run the example in a ``linux`` environment:
 
 .. code-block:: console
 
-    ./<build_dir>/examples/dpdk-ptpclient -l 1 -n 4 -- -p 0x1 -T 0 -c 1
+    ./<build_dir>/examples/dpdk-ptpclient -l 1 -n 4 -- -p 0x1 -T 0
 
 Refer to *DPDK Getting Started Guide* for general information on running
 applications and the Environment Abstraction Layer (EAL) options.
@@ -79,15 +73,6 @@ applications and the Environment Abstraction Layer (EAL) options.
 * ``-p portmask``: Hexadecimal portmask.
 * ``-T 0``: Update only the PTP time receiver clock.
 * ``-T 1``: Update the PTP time receiver clock and synchronize the Linux Kernel to the PTP clock.
-* ``-c 0``: Not used clock servo controller.
-* ``-c 1``: The clock servo PI controller is used and the log will print information
-            about time transmitter offset.
-            Note that the PMD needs to support the ``rte_eth_timesync_adjust_freq()`` API
-            to enable the servo controller.
-
-Also, by adding ``-T 1`` and ``-c 1``, the time transmitter offset value printed in the log
-will slowly converge and eventually stabilise at the nanosecond level.
-The synchronisation accuracy is much higher compared to not using a servo controller.
 
 
 Code Explanation
diff --git a/examples/ptpclient/ptpclient.c b/examples/ptpclient/ptpclient.c
index 23fa487081..7b6862d951 100644
--- a/examples/ptpclient/ptpclient.c
+++ b/examples/ptpclient/ptpclient.c
@@ -46,35 +46,6 @@ static volatile bool force_quit;
 #define KERNEL_TIME_ADJUST_LIMIT  20000
 #define PTP_PROTOCOL             0x88F7
 
-#define KP 0.7
-#define KI 0.3
-#define FREQ_EST_MARGIN 0.001
-
-enum servo_state {
-	SERVO_UNLOCKED,
-	SERVO_JUMP,
-	SERVO_LOCKED,
-};
-
-struct pi_servo {
-	double offset[2];
-	double local[2];
-	double drift;
-	double last_freq;
-	int count;
-
-	double max_frequency;
-	double step_threshold;
-	double first_step_threshold;
-	int first_update;
-};
-
-enum controller_mode {
-	MODE_NONE,
-	MODE_PI,
-	MAX_ALL
-} mode = MODE_NONE;
-
 struct rte_mempool *mbuf_pool;
 uint32_t ptp_enabled_port_mask;
 uint8_t ptp_enabled_port_nb;
@@ -164,9 +135,6 @@ struct ptpv2_time_receiver_ordinary {
 	uint8_t ptpset;
 	uint8_t kernel_time_set;
 	uint16_t current_ptp_port;
-	int64_t master_offset;
-	int64_t path_delay;
-	struct pi_servo *servo;
 };
 
 static struct ptpv2_time_receiver_ordinary ptp_data;
@@ -294,19 +262,6 @@ port_init(uint16_t port, struct rte_mempool *mbuf_pool)
 		return retval;
 	}
 
-	/*
-	 * If the clock servo controller is enabled, the PMD must support
-	 * adjustment of the clock frequency.
-	 */
-	if (mode != MODE_NONE) {
-		retval = rte_eth_timesync_adjust_freq(port, 0);
-		if (retval == -ENOTSUP) {
-			printf("The servo controller cannot work on devices that"
-					" do not support frequency adjustment.\n");
-			return retval;
-		}
-	}
-
 	return 0;
 }
 
@@ -342,40 +297,33 @@ print_clock_info(struct ptpv2_time_receiver_ordinary *ptp_data)
 			ptp_data->tstamp4.tv_sec,
 			(ptp_data->tstamp4.tv_nsec));
 
-	if (mode == MODE_NONE) {
-		printf("\nDelta between transmitter and receiver clocks:%"PRId64"ns\n",
-			ptp_data->delta);
+	printf("\nDelta between transmitter and receiver clocks:%"PRId64"ns\n",
+		ptp_data->delta);
 
-		clock_gettime(CLOCK_REALTIME, &sys_time);
-		rte_eth_timesync_read_time(ptp_data->current_ptp_port,
-					   &net_time);
+	clock_gettime(CLOCK_REALTIME, &sys_time);
+	rte_eth_timesync_read_time(ptp_data->current_ptp_port,
+					&net_time);
 
-		time_t ts = net_time.tv_sec;
+	time_t ts = net_time.tv_sec;
 
-		printf("\n\nComparison between Linux kernel Time and PTP:");
+	printf("\n\nComparison between Linux kernel Time and PTP:");
 
-		printf("\nCurrent PTP Time: %.24s %.9ld ns",
-			ctime(&ts), net_time.tv_nsec);
+	printf("\nCurrent PTP Time: %.24s %.9ld ns",
+		ctime(&ts), net_time.tv_nsec);
 
-		nsec = (int64_t)timespec64_to_ns(&net_time) -
-			(int64_t)timespec64_to_ns(&sys_time);
-		ptp_data->new_adj = ns_to_timeval(nsec);
+	nsec = (int64_t)timespec64_to_ns(&net_time) -
+		(int64_t)timespec64_to_ns(&sys_time);
+	ptp_data->new_adj = ns_to_timeval(nsec);
 
-		gettimeofday(&ptp_data->new_adj, NULL);
+	gettimeofday(&ptp_data->new_adj, NULL);
 
-		time_t tp = ptp_data->new_adj.tv_sec;
+	time_t tp = ptp_data->new_adj.tv_sec;
 
-		printf("\nCurrent SYS Time: %.24s %.6ld ns",
-			ctime(&tp), ptp_data->new_adj.tv_usec);
+	printf("\nCurrent SYS Time: %.24s %.6ld ns",
+		ctime(&tp), ptp_data->new_adj.tv_usec);
 
-		printf("\nDelta between PTP and Linux Kernel time:%"PRId64"ns\n",
-			nsec);
-	}
-
-	if (mode == MODE_PI) {
-		printf("path delay: %"PRId64"ns\n", ptp_data->path_delay);
-		printf("time transmitter offset: %"PRId64"ns\n", ptp_data->master_offset);
-	}
+	printf("\nDelta between PTP and Linux Kernel time:%"PRId64"ns\n",
+		nsec);
 
 	printf("[Ctrl+C to quit]\n");
 
@@ -582,149 +530,6 @@ update_kernel_time(void)
 
 }
 
-static void
-clock_path_delay(struct ptpv2_time_receiver_ordinary *ptp_data)
-{
-	uint64_t t1_ns, t2_ns, t3_ns, t4_ns;
-	int64_t pd, diff;
-
-	t1_ns = timespec64_to_ns(&ptp_data->tstamp1);
-	t2_ns = timespec64_to_ns(&ptp_data->tstamp2);
-	t3_ns = timespec64_to_ns(&ptp_data->tstamp3);
-	t4_ns = timespec64_to_ns(&ptp_data->tstamp4);
-
-	pd = (t2_ns - t3_ns) + (t4_ns - t1_ns);
-	diff = t3_ns - t2_ns;
-	if (diff <= INT32_MAX && diff >= INT32_MIN)
-		ptp_data->path_delay = pd / 2;
-	else
-		ptp_data->path_delay = 0;
-}
-
-static double
-pi_sample(struct pi_servo *s, int64_t offset, double local_ts,
-	  enum servo_state *state)
-{
-	double ki_term, ppb = s->last_freq;
-	double freq_est_interval, localdiff;
-
-	switch (s->count) {
-	case 0:
-		s->offset[0] = offset;
-		s->local[0] = local_ts;
-		*state = SERVO_UNLOCKED;
-		s->count = 1;
-		break;
-	case 1:
-		s->offset[1] = offset;
-		s->local[1] = local_ts;
-
-		/* Make sure the first sample is older than the second. */
-		if (s->local[0] >= s->local[1]) {
-			*state = SERVO_UNLOCKED;
-			s->count = 0;
-			break;
-		}
-
-		/* Wait long enough before estimating the frequency offset. */
-		localdiff = (s->local[1] - s->local[0]) / 1e9;
-		localdiff += localdiff * FREQ_EST_MARGIN;
-		freq_est_interval = 0.016 / KI;
-		if (freq_est_interval > 1000.0)
-			freq_est_interval = 1000.0;
-
-		if (localdiff < freq_est_interval) {
-			*state = SERVO_UNLOCKED;
-			break;
-		}
-
-		/* Adjust drift by the measured frequency offset. */
-		s->drift += (1e9 - s->drift) * (s->offset[1] - s->offset[0]) /
-						(s->local[1] - s->local[0]);
-
-		if (s->drift < -s->max_frequency)
-			s->drift = -s->max_frequency;
-		else if (s->drift > s->max_frequency)
-			s->drift = s->max_frequency;
-
-		if ((s->first_update &&
-		     s->first_step_threshold &&
-		     s->first_step_threshold < llabs(offset)) ||
-		    (s->step_threshold &&
-		     s->step_threshold < llabs(offset)))
-			*state = SERVO_JUMP;
-		else
-			*state = SERVO_LOCKED;
-
-		ppb = s->drift;
-		s->count = 2;
-		break;
-	case 2:
-		/*
-		 * reset the clock servo when offset is greater than the max
-		 * offset value. Note that the clock jump will be performed in
-		 * step 1, so it is not necessary to have clock jump
-		 * immediately. This allows re-calculating drift as in initial
-		 * clock startup.
-		 */
-		if (s->step_threshold &&
-		    s->step_threshold < llabs(offset)) {
-			*state = SERVO_UNLOCKED;
-			s->count = 0;
-			break;
-		}
-
-		ki_term = KI * offset;
-		ppb = KP * offset + s->drift + ki_term;
-		if (ppb < -s->max_frequency)
-			ppb = -s->max_frequency;
-		else if (ppb > s->max_frequency)
-			ppb = s->max_frequency;
-		else
-			s->drift += ki_term;
-
-		*state = SERVO_LOCKED;
-		break;
-	}
-
-	s->last_freq = ppb;
-	return ppb;
-}
-
-static void
-ptp_adjust_servo(struct ptpv2_time_receiver_ordinary *ptp_data)
-{
-	uint64_t t1_ns, t2_ns;
-	double adj_freq;
-	enum servo_state state = SERVO_UNLOCKED;
-
-	t1_ns = timespec64_to_ns(&ptp_data->tstamp1);
-	t2_ns = timespec64_to_ns(&ptp_data->tstamp2);
-	ptp_data->master_offset = t2_ns - t1_ns - ptp_data->path_delay;
-	if (!ptp_data->path_delay)
-		return;
-
-	adj_freq = pi_sample(ptp_data->servo, ptp_data->master_offset, t2_ns,
-		     &state);
-
-	switch (state) {
-	case SERVO_UNLOCKED:
-		break;
-	case SERVO_JUMP:
-		ptp_data->servo->first_update = 0;
-		rte_eth_timesync_adjust_freq(ptp_data->portid,
-						-(long)(adj_freq * 65.536));
-		rte_eth_timesync_adjust_time(ptp_data->portid,
-					     -ptp_data->master_offset);
-		break;
-	case SERVO_LOCKED:
-		ptp_data->servo->first_update = 0;
-		rte_eth_timesync_adjust_freq(ptp_data->portid,
-					     -(long)(adj_freq * 65.536));
-		break;
-	}
-}
-
 /*
  * Parse the DELAY_RESP message.
  */
@@ -749,16 +554,11 @@ parse_drsp(struct ptpv2_time_receiver_ordinary *ptp_data)
 				((uint64_t)ntohl(rx_tstamp->sec_lsb)) |
 				(((uint64_t)ntohs(rx_tstamp->sec_msb)) << 32);
 
-			if (mode == MODE_PI) {
-				clock_path_delay(ptp_data);
-				ptp_adjust_servo(ptp_data);
-			} else {
-				/* Evaluate the delta for adjustment. */
-				ptp_data->delta = delta_eval(ptp_data);
+			/* Evaluate the delta for adjustment. */
+			ptp_data->delta = delta_eval(ptp_data);
 
-				rte_eth_timesync_adjust_time(ptp_data->portid,
-								ptp_data->delta);
-			}
+			rte_eth_timesync_adjust_time(ptp_data->portid,
+							ptp_data->delta);
 
 			ptp_data->current_ptp_port = ptp_data->portid;
 
@@ -853,9 +653,7 @@ print_usage(const char *prgname)
 	printf("%s [EAL options] -- -p PORTMASK -T VALUE\n"
 		" -T VALUE: 0 - Disable, 1 - Enable Linux Clock"
 		" Synchronization (0 default)\n"
-		" -p PORTMASK: hexadecimal bitmask of ports to configure\n"
-		" -c CONTROLLER: 0 - Not used, 1 - PI. The servo which is"
-		" used to synchronize the local clock. (0 default)\n",
+		" -p PORTMASK: hexadecimal bitmask of ports to configure\n",
 		prgname);
 }
 
@@ -891,36 +689,6 @@ parse_ptp_kernel(const char *param)
 	return 1;
 }
 
-static int
-parse_ptp_servo_mode(const char *param)
-{
-	char *end = NULL;
-	unsigned long pm;
-
-	/* Parse the hexadecimal string. */
-	pm = strtoul(param, &end, 10);
-
-	if ((param[0] == '\0') || (end == NULL) || (*end != '\0'))
-		return -1;
-
-	return pm;
-}
-
-static void
-servo_init(struct pi_servo *servo)
-{
-	memset(servo, 0x00, sizeof(*servo));
-
-	servo->drift = 100000000;
-	servo->last_freq = 100000000;
-	servo->count = 0;
-
-	servo->max_frequency = 100000000;
-	servo->step_threshold = 0.1 * NSEC_PER_SEC;
-	servo->first_step_threshold = 0.00002 * NSEC_PER_SEC;
-	servo->first_update = 1;
-}
-
 /* Parse the commandline arguments. */
 static int
 ptp_parse_args(int argc, char **argv)
@@ -933,7 +701,7 @@ ptp_parse_args(int argc, char **argv)
 
 	argvopt = argv;
 
-	while ((opt = getopt_long(argc, argvopt, "p:T:c:",
+	while ((opt = getopt_long(argc, argvopt, "p:T:",
 				  lgopts, &option_index)) != EOF) {
 
 		switch (opt) {
@@ -957,17 +725,6 @@ ptp_parse_args(int argc, char **argv)
 
 			ptp_data.kernel_time_set = ret;
 			break;
-		case 'c':
-			ret = parse_ptp_servo_mode(optarg);
-			if (ret == 0) {
-				mode = MODE_NONE;
-			} else if (ret == 1) {
-				mode = MODE_PI;
-			} else {
-				print_usage(prgname);
-				return -1;
-			}
-			break;
 
 		default:
 			print_usage(prgname);
@@ -1022,14 +779,6 @@ main(int argc, char *argv[])
 		rte_exit(EXIT_FAILURE, "Error with PTP initialization\n");
 	/* >8 End of parsing specific arguments. */
 
-	if (mode == MODE_PI) {
-		ptp_data.servo = malloc(sizeof(*(ptp_data.servo)));
-		if (!ptp_data.servo)
-			rte_exit(EXIT_FAILURE, "no memory for servo\n");
-
-		servo_init(ptp_data.servo);
-	}
-
 	/* Check that there is an even number of ports to send/receive on. */
 	nb_ports = rte_eth_dev_count_avail();
 
@@ -1083,9 +832,6 @@ main(int argc, char *argv[])
 		rte_eth_dev_close(portid);
 	}
 
-	if (mode == MODE_PI)
-		free(ptp_data.servo);
-
 	/* clean up the EAL */
 	rte_eal_cleanup();
 
-- 
2.25.1