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685060e12c0eab63db10794033a7f69ff8d057ef
aes67-ESP32-P4/components/aes67_ptp/ptp_clock.c
T
bsncubed 685060e12c Step 3.3a: PTP servo, clock locks to the GM 
- ptp_hw: ptp_hw_adj_freq() (ETH_MAC_ESP_CMD_ADJ_PTP_TIME, absolute ppb
  vs nominal, clamped +-500 ppm, retried while the addend update is
  busy) and ptp_hw_step() (read + write time).
- ptp_clock: first Sync after a GM is selected seeds the integral with
  the measured rate and steps the clock; then linuxptp-style PI (kp/ki
  from the Sync interval: 0.7/0.3 at 1 s). Re-step above 1 ms. Locked
  after 8 Syncs with |offset| < 1 us, unlocked after 3 above; GM change
  or loss unlocks and keeps the frequency (holdover).
- Verified vs ptp4l: stepped to GM time, locked after ~19 s; locked
  offset within +-510 ns (mostly < 300 ns), correction +39.9 ppm
  (crystal -39.8 ppm), path delay ~10.2 us.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-25 06:15:26 +10:00

412 lines
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C
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#include "ptp_clock.h"
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "aes67_cfg.h"
#include "esp_log.h"
#include "esp_random.h"
#include "esp_timer.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "lwip/sockets.h"
#include "ptp_hw.h"
#define PTP_MCAST "224.0.1.129"
#define PTP_EVENT_PORT 319
#define PTP_GENERAL_PORT 320
#define HDR_LEN 34
#define FLAG_TWO_STEP 0x0200
#define STEP_NS 1000000 // re-step instead of slewing above 1 ms
#define LOCK_NS 1000 // |offset| below this counts as good
#define LOCK_GOOD 8 // consecutive good Syncs to lock
#define LOCK_BAD 3 // consecutive bad Syncs to unlock
#define MAX_DRIFT_PPB 500000.0
static const char *TAG = "ptp";
static const uint8_t PTP_MCAST_MAC[6] = { 0x01, 0x00, 0x5e, 0x00, 0x01, 0x81 };
typedef struct {
bool valid;
uint8_t port_id[10]; // sourcePortIdentity of the GM (clockId + port)
uint32_t ip; // source address, for hybrid mode later
uint8_t p1, cls, acc, p2;
uint16_t var;
uint8_t gm_id[8];
uint16_t steps;
int8_t log_announce;
int64_t last_us; // last Announce (esp_timer)
} master_t;
static struct {
esp_netif_t *netif;
int ev, gen;
uint8_t domain, dscp, timeout;
uint8_t port_id[10]; // our clockId (EUI-64 from MAC) + port 1
master_t gm;
// Sync / Follow_Up
uint16_t sync_seq;
bool sync_pending;
int64_t t1, t2, sync_corr;
// Delay_Req / Delay_Resp
uint16_t dreq_seq;
bool dreq_pending;
int64_t t3;
int8_t log_dreq; // from Delay_Resp logMessageInterval
int64_t next_dreq_us;
int64_t delay_ns; // mean path delay, 0 = not measured yet
// Drift of (t2 - t1) between Syncs: corrects the delay for the time between t2 and t3
// while the local clock is not yet syntonised.
int64_t raw, prev_raw, prev_t2;
double rate;
int8_t log_sync; // GM's Sync interval (from Sync logMessageInterval)
// Servo (PI, linuxptp-style gains)
bool stepped; // clock set to GM time since this GM was selected
double drift_ppb; // integral term
double freq_ppb; // correction currently applied (positive = faster)
int64_t offset_ns;
int good, bad;
bool locked;
} s;
static void set_locked(bool locked);
/* ----- helpers ----- */
static uint16_t rd16(const uint8_t *p) { return (p[0] << 8) | p[1]; }
static int64_t rd_ts(const uint8_t *p) // 48-bit seconds + 32-bit ns
{
uint64_t sec = ((uint64_t)rd16(p) << 32) | ((uint32_t)p[2] << 24) | (p[3] << 16) | (p[4] << 8) | p[5];
uint32_t ns = ((uint32_t)p[6] << 24) | (p[7] << 16) | (p[8] << 8) | p[9];
return (int64_t)sec * 1000000000LL + ns;
}
static int64_t rd_corr_ns(const uint8_t *p) // correctionField: ns * 2^16
{
int64_t v = 0;
for (int i = 0; i < 8; i++) {
v = (v << 8) | p[i];
}
return v >> 16;
}
static int64_t mac_ns(const eth_mac_time_t *t)
{
return (int64_t)t->seconds * 1000000000LL + t->nanoseconds;
}
static void fmt_id(char *out, const uint8_t *id)
{
sprintf(out, "%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x", id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7]);
}
// IEEE 1588 dataset comparison (without the topology part): <0 if a is better.
static int compare(const master_t *a, const master_t *b)
{
if (a->p1 != b->p1) return a->p1 - b->p1;
if (a->cls != b->cls) return a->cls - b->cls;
if (a->acc != b->acc) return a->acc - b->acc;
if (a->var != b->var) return a->var - b->var;
if (a->p2 != b->p2) return a->p2 - b->p2;
int c = memcmp(a->gm_id, b->gm_id, 8);
if (c) return c;
return a->steps - b->steps;
}
static int open_socket(uint16_t port, struct in_addr ifaddr)
{
int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
int one = 1;
setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
struct sockaddr_in a = { .sin_family = AF_INET, .sin_port = htons(port), .sin_addr.s_addr = htonl(INADDR_ANY) };
struct ip_mreq m = { .imr_interface = ifaddr };
inet_aton(PTP_MCAST, &m.imr_multiaddr);
if (bind(fd, (struct sockaddr *)&a, sizeof(a)) < 0 ||
setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &m, sizeof(m)) < 0) {
ESP_LOGE(TAG, "socket %u: bind/join failed (errno %d)", port, errno);
close(fd);
return -1;
}
return fd;
}
static bool from_gm(const uint8_t *b)
{
return s.gm.valid && memcmp(b + 20, s.gm.port_id, 10) == 0;
}
/* ----- message handling ----- */
static void on_announce(const uint8_t *b, int len, uint32_t src_ip)
{
if (len < 64) {
return;
}
master_t m = {
.valid = true, .ip = src_ip, .p1 = b[47], .cls = b[48], .acc = b[49], .var = rd16(b + 50),
.p2 = b[52], .steps = rd16(b + 61), .log_announce = (int8_t)b[33], .last_us = esp_timer_get_time(),
};
memcpy(m.port_id, b + 20, 10);
memcpy(m.gm_id, b + 53, 8);
if (memcmp(m.port_id, s.port_id, 10) == 0) {
return; // our own
}
if (from_gm(b)) {
s.gm = m; // refresh dataset and timeout
} else if (!s.gm.valid || compare(&m, &s.gm) < 0) {
char id[24];
fmt_id(id, m.gm_id);
ESP_LOGI(TAG, "TimeTransmitter %s (p1 %u class %u p2 %u, %u hops) from " IPSTR,
id, m.p1, m.cls, m.p2, m.steps, IP2STR((esp_ip4_addr_t *)&src_ip));
s.gm = m;
s.sync_pending = s.dreq_pending = false;
s.delay_ns = s.prev_t2 = 0;
s.stepped = false;
set_locked(false);
s.log_dreq = 0;
s.next_dreq_us = 0;
}
}
static void set_locked(bool locked)
{
if (locked != s.locked) {
s.locked = locked;
if (locked) {
ESP_LOGI(TAG, "locked: offset %+lld ns, frequency %+.3f ppm, path delay %lld ns",
s.offset_ns, s.freq_ppb / 1000, s.delay_ns);
} else {
ESP_LOGW(TAG, "unlocked");
}
}
if (!locked) {
s.good = 0;
}
}
// offset = local - GM (ns)
static void servo(int64_t offset)
{
s.offset_ns = offset;
if (!s.stepped || llabs(offset) > STEP_NS) {
if (!s.stepped) {
// Seed the integral with the measured rate error (measured with the current correction applied).
s.drift_ppb += s.rate * 1e9;
}
s.freq_ppb = -s.drift_ppb;
ptp_hw_adj_freq(s.freq_ppb);
esp_err_t err = ptp_hw_step(offset);
ESP_LOGI(TAG, "clock stepped by %+lld ns (%s), frequency %+.3f ppm", -offset, esp_err_to_name(err),
s.freq_ppb / 1000);
s.stepped = true;
s.prev_t2 = 0; // rate across the step is meaningless
s.bad = 0;
set_locked(false);
return;
}
// linuxptp PI gains for hardware timestamps, scaled by the Sync interval
double iv = ldexp(1.0, s.log_sync);
double kp = fmin(0.7 * pow(iv, -0.3), 0.7 / iv);
double ki = fmin(0.3 * pow(iv, 0.4), 0.3 / iv);
double ppb = kp * offset + s.drift_ppb;
s.drift_ppb = fmax(-MAX_DRIFT_PPB, fmin(MAX_DRIFT_PPB, s.drift_ppb + ki * offset));
s.freq_ppb = -ppb;
ptp_hw_adj_freq(s.freq_ppb);
if (llabs(offset) < LOCK_NS) {
s.bad = 0;
if (++s.good >= LOCK_GOOD) {
set_locked(true);
}
} else {
s.good = 0;
if (s.locked && ++s.bad >= LOCK_BAD) {
set_locked(false);
}
}
}
static void sync_complete(void)
{
s.sync_pending = false;
s.raw = s.t2 - s.t1 - s.sync_corr;
if (s.prev_t2 && s.t2 > s.prev_t2) {
s.rate = (double)(s.raw - s.prev_raw) / (double)(s.t2 - s.prev_t2);
}
s.prev_raw = s.raw;
s.prev_t2 = s.t2;
if (!s.delay_ns) {
return;
}
// offset = t2 - t1 - corrections - mean path delay
servo(s.raw - s.delay_ns);
ESP_LOGI(TAG, "seq %u: offset %+lld ns, freq %+.3f ppm, path delay %lld ns%s", s.sync_seq, s.offset_ns,
s.freq_ppb / 1000, s.delay_ns, s.locked ? ", locked" : "");
}
static void on_sync(const uint8_t *b, int len)
{
if (len < 44 || !from_gm(b)) {
return;
}
eth_mac_time_t t2;
uint16_t seq = rd16(b + 30);
if (!ptp_hw_rx_ts(PTP_MSG_SYNC, seq, b + 20, &t2)) {
ESP_LOGW(TAG, "Sync %u: no HW RX timestamp", seq);
return;
}
s.sync_seq = seq;
s.log_sync = (int8_t)b[33];
s.t2 = mac_ns(&t2);
s.sync_corr = rd_corr_ns(b + 8);
if (rd16(b + 6) & FLAG_TWO_STEP) {
s.sync_pending = true; // wait for Follow_Up
} else {
s.t1 = rd_ts(b + 34);
sync_complete();
}
}
static void on_follow_up(const uint8_t *b, int len)
{
if (len < 44 || !from_gm(b) || !s.sync_pending || rd16(b + 30) != s.sync_seq) {
return;
}
s.t1 = rd_ts(b + 34);
s.sync_corr += rd_corr_ns(b + 8);
sync_complete();
}
static void send_delay_req(void)
{
uint8_t m[44] = { 0 };
m[0] = PTP_MSG_DELAY_REQ;
m[1] = 2;
m[3] = sizeof(m);
m[4] = s.domain;
memcpy(m + 20, s.port_id, 10);
s.dreq_seq++;
m[30] = s.dreq_seq >> 8;
m[31] = s.dreq_seq & 0xff;
m[32] = 1; // controlField: Delay_Req
m[33] = 0x7f;
uint32_t dst;
inet_aton(PTP_MCAST, (struct in_addr *)&dst);
eth_mac_time_t t3;
esp_err_t err = ptp_hw_send_event(PTP_MCAST_MAC, dst, s.dscp, m, sizeof(m), &t3);
if (err != ESP_OK) {
ESP_LOGW(TAG, "Delay_Req %u: %s", s.dreq_seq, esp_err_to_name(err));
s.dreq_pending = false;
return;
}
s.t3 = mac_ns(&t3);
s.dreq_pending = true;
}
static void on_delay_resp(const uint8_t *b, int len)
{
if (len < 54 || !from_gm(b) || !s.dreq_pending || rd16(b + 30) != s.dreq_seq ||
memcmp(b + 44, s.port_id, 10) != 0) {
return;
}
s.dreq_pending = false;
int64_t t4 = rd_ts(b + 34) - rd_corr_ns(b + 8);
s.log_dreq = (int8_t)b[33];
if (!s.prev_t2) {
return;
}
// mean path delay = ((t2 - t1 - corr) + (t4 - t3)) / 2, plus the offset drift between t2 and t3
int64_t d = (s.raw + (t4 - s.t3) + (int64_t)(s.rate * (double)(s.t3 - s.t2))) / 2;
s.delay_ns = s.delay_ns ? (s.delay_ns * 7 + d) / 8 : d; // light smoothing
}
/* ----- task ----- */
static void load_config(void)
{
cJSON *c = cfg_get("ptp");
s.domain = cJSON_GetObjectItem(c, "domain")->valueint;
s.dscp = cJSON_GetObjectItem(c, "dscp")->valueint;
s.timeout = cJSON_GetObjectItem(c, "announce_timeout")->valueint;
cJSON_Delete(c);
}
static void ptp_task(void *arg)
{
esp_netif_ip_info_t ip = { 0 };
while (esp_netif_get_ip_info(s.netif, &ip) != ESP_OK || !ip.ip.addr) {
vTaskDelay(pdMS_TO_TICKS(500));
}
struct in_addr ifaddr = { .s_addr = ip.ip.addr };
s.ev = open_socket(PTP_EVENT_PORT, ifaddr);
s.gen = open_socket(PTP_GENERAL_PORT, ifaddr);
if (s.ev < 0 || s.gen < 0) {
vTaskDelete(NULL);
}
char id[24];
fmt_id(id, s.port_id);
ESP_LOGI(TAG, "TimeReceiver on " IPSTR ", domain %u, clock %s, listening", IP2STR(&ip.ip), s.domain, id);
uint8_t b[128];
while (1) {
fd_set fds;
FD_ZERO(&fds);
FD_SET(s.ev, &fds);
FD_SET(s.gen, &fds);
struct timeval tv = { .tv_sec = 0, .tv_usec = 100000 };
if (select((s.ev > s.gen ? s.ev : s.gen) + 1, &fds, NULL, NULL, &tv) > 0) {
for (int k = 0; k < 2; k++) {
int fd = k ? s.gen : s.ev;
if (!FD_ISSET(fd, &fds)) {
continue;
}
struct sockaddr_in src;
socklen_t sl = sizeof(src);
int len = recvfrom(fd, b, sizeof(b), 0, (struct sockaddr *)&src, &sl);
if (len < HDR_LEN || (b[1] & 0x0f) != 2 || b[4] != s.domain) {
continue;
}
switch (b[0] & 0x0f) {
case PTP_MSG_ANNOUNCE: on_announce(b, len, src.sin_addr.s_addr); break;
case PTP_MSG_SYNC: on_sync(b, len); break;
case PTP_MSG_FOLLOW_UP: on_follow_up(b, len); break;
case PTP_MSG_DELAY_RESP: on_delay_resp(b, len); break;
default: break;
}
}
}
int64_t now = esp_timer_get_time();
if (s.gm.valid) {
// announceReceiptTimeout x the GM's announce interval
int64_t window = (int64_t)s.timeout * (s.gm.log_announce >= 0 ? 1000000LL << s.gm.log_announce
: 1000000LL >> -s.gm.log_announce);
if (now - s.gm.last_us > window) {
ESP_LOGW(TAG, "TimeTransmitter lost (no Announce for %lld ms), listening", window / 1000);
memset(&s.gm, 0, sizeof(s.gm));
s.delay_ns = s.prev_t2 = 0;
s.stepped = false;
set_locked(false); // frequency correction stays (holdover)
} else if (now >= s.next_dreq_us && s.prev_t2) {
send_delay_req();
// Delay_Req interval from the GM's Delay_Resp; randomised 0.5..1.5x
int64_t iv = s.log_dreq >= 0 ? 1000000LL << s.log_dreq : 1000000LL >> -s.log_dreq;
s.next_dreq_us = now + iv / 2 + (esp_random() % (uint32_t)iv);
}
}
}
}
esp_err_t ptp_clock_start(esp_netif_t *netif)
{
s.netif = netif;
load_config();
uint8_t mac[6];
esp_netif_get_mac(netif, mac);
const uint8_t pid[10] = { mac[0], mac[1], mac[2], 0xff, 0xfe, mac[3], mac[4], mac[5], 0, 1 };
memcpy(s.port_id, pid, sizeof(pid));
return xTaskCreate(ptp_task, "ptp", 4096, NULL, 10, NULL) == pdPASS ? ESP_OK : ESP_ERR_NO_MEM;
}
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