From: Jakub Kicinski <kuba@kernel.org>
Date: Wed, 20 May 2026 22:11:51 +0000 (-0700)
Subject: Revert "Merge branch 'gve-add-support-for-ptp-gettimex64'"
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0ae361f7e43ca820e1f6219759358b4e71dc26dc;p=thirdparty%2Flinux.git

Revert "Merge branch 'gve-add-support-for-ptp-gettimex64'"

This reverts commit 9587ed8137fb83d93f84b858337412f4500b21e9,
reversing changes made to bcdfd9fb109e0c9d76c345b2346b6b75ed1f476d.

Per tglx's objections: https://lore.kernel.org/87mrxtwzz9.ffs@tglx

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index 4de3ce60060e0..1d66d3834f7e6 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -792,9 +792,6 @@ struct gve_ptp {
 	struct ptp_clock_info info;
 	struct ptp_clock *clock;
 	struct gve_priv *priv;
-	struct mutex nic_ts_read_lock; /* Protects nic_ts_report */
-	struct gve_nic_ts_report *nic_ts_report;
-	dma_addr_t nic_ts_report_bus;
 };
 
 struct gve_priv {
@@ -880,14 +877,6 @@ struct gve_priv {
 	u32 stats_report_trigger_cnt; /* count of device-requested stats-reports since last reset */
 	u32 suspend_cnt; /* count of times suspended */
 	u32 resume_cnt; /* count of times resumed */
-	/* count of cross-timestamps attempted using system timestamps
-	 * from the AQ command
-	 */
-	u32 ptp_precise_xtstamps;
-	/* count of cross-timestamps attempted using system timestamps sampled
-	 * by the driver
-	 */
-	u32 ptp_fallback_xtstamps;
 	struct workqueue_struct *gve_wq;
 	struct work_struct service_task;
 	struct work_struct stats_report_task;
@@ -934,6 +923,8 @@ struct gve_priv {
 	bool nic_timestamp_supported;
 	struct gve_ptp *ptp;
 	struct kernel_hwtstamp_config ts_config;
+	struct gve_nic_ts_report *nic_ts_report;
+	dma_addr_t nic_ts_report_bus;
 	u64 last_sync_nic_counter; /* Clock counter from last NIC TS report */
 };
 
@@ -1210,7 +1201,7 @@ static inline bool gve_supports_xdp_xmit(struct gve_priv *priv)
 
 static inline bool gve_is_clock_enabled(struct gve_priv *priv)
 {
-	return priv->ptp;
+	return priv->nic_ts_report;
 }
 
 /* gqi napi handler defined in gve_main.c */
@@ -1330,9 +1321,14 @@ int gve_flow_rules_reset(struct gve_priv *priv);
 int gve_init_rss_config(struct gve_priv *priv, u16 num_queues);
 /* PTP and timestamping */
 #if IS_ENABLED(CONFIG_PTP_1588_CLOCK)
+int gve_clock_nic_ts_read(struct gve_priv *priv);
 int gve_init_clock(struct gve_priv *priv);
 void gve_teardown_clock(struct gve_priv *priv);
 #else /* CONFIG_PTP_1588_CLOCK */
+static inline int gve_clock_nic_ts_read(struct gve_priv *priv)
+{
+	return -EOPNOTSUPP;
+}
 
 static inline int gve_init_clock(struct gve_priv *priv)
 {
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
index 0d5a67523cbab..08587bf40ed4a 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.c
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -416,10 +416,16 @@ static bool gve_adminq_wait_for_cmd(struct gve_priv *priv, u32 prod_cnt)
 
 static int gve_adminq_parse_err(struct gve_priv *priv, u32 status)
 {
+	if (status != GVE_ADMINQ_COMMAND_PASSED &&
+	    status != GVE_ADMINQ_COMMAND_UNSET) {
+		dev_err(&priv->pdev->dev, "AQ command failed with status %d\n", status);
+		priv->adminq_cmd_fail++;
+	}
 	switch (status) {
 	case GVE_ADMINQ_COMMAND_PASSED:
 		return 0;
 	case GVE_ADMINQ_COMMAND_UNSET:
+		dev_err(&priv->pdev->dev, "parse_aq_err: err and status both unset, this should not be possible.\n");
 		return -EINVAL;
 	case GVE_ADMINQ_COMMAND_ERROR_ABORTED:
 	case GVE_ADMINQ_COMMAND_ERROR_CANCELLED:
@@ -449,27 +455,6 @@ static int gve_adminq_parse_err(struct gve_priv *priv, u32 status)
 	}
 }
 
-static bool gve_adminq_is_retryable(enum gve_adminq_opcodes opcode)
-{
-	switch (opcode) {
-	case GVE_ADMINQ_REPORT_NIC_TIMESTAMP:
-		return true;
-	default:
-		return false;
-	}
-}
-
-static enum gve_adminq_opcodes gve_extract_opcode(union gve_adminq_command *cmd)
-{
-	u32 opcode;
-
-	opcode = be32_to_cpu(READ_ONCE(cmd->opcode));
-	if (opcode == GVE_ADMINQ_EXTENDED_COMMAND)
-		opcode = be32_to_cpu(cmd->extended_command.inner_opcode);
-
-	return opcode;
-}
-
 /* Flushes all AQ commands currently queued and waits for them to complete.
  * If there are failures, it will return the first error.
  */
@@ -492,24 +477,14 @@ static int gve_adminq_kick_and_wait(struct gve_priv *priv)
 
 	for (i = tail; i < head; i++) {
 		union gve_adminq_command *cmd;
-		u32 status;
-		int err;
+		u32 status, err;
 
 		cmd = &priv->adminq[i & priv->adminq_mask];
 		status = be32_to_cpu(READ_ONCE(cmd->status));
 		err = gve_adminq_parse_err(priv, status);
-		if (err) {
-			enum gve_adminq_opcodes opcode = gve_extract_opcode(cmd);
-
-			priv->adminq_cmd_fail++;
-			if (!gve_adminq_is_retryable(opcode) || err != -EAGAIN)
-				dev_err_ratelimited(&priv->pdev->dev,
-						    "AQ command %d failed with status %d\n",
-						    opcode, status);
-
+		if (err)
 			// Return the first error if we failed.
 			return err;
-		}
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.h b/drivers/net/ethernet/google/gve/gve_adminq.h
index e6dcf6da9091d..22a74b6aa17ea 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.h
+++ b/drivers/net/ethernet/google/gve/gve_adminq.h
@@ -411,8 +411,8 @@ static_assert(sizeof(struct gve_adminq_report_nic_ts) == 16);
 
 struct gve_nic_ts_report {
 	__be64 nic_timestamp; /* NIC clock in nanoseconds */
-	__be64 pre_cycles; /* System cycle counter before NIC clock read */
-	__be64 post_cycles; /* System cycle counter after NIC clock read */
+	__be64 reserved1;
+	__be64 reserved2;
 	__be64 reserved3;
 	__be64 reserved4;
 };
diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index 8a088dcc3603e..dc2213b5ce246 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -46,7 +46,6 @@ static const char gve_gstrings_main_stats[][ETH_GSTRING_LEN] = {
 	"rx_hsplit_unsplit_pkt",
 	"interface_up_cnt", "interface_down_cnt", "reset_cnt",
 	"page_alloc_fail", "dma_mapping_error", "stats_report_trigger_cnt",
-	"ptp_precise_xtstamps", "ptp_fallback_xtstamps",
 };
 
 static const char gve_gstrings_rx_stats[][ETH_GSTRING_LEN] = {
@@ -270,8 +269,6 @@ gve_get_ethtool_stats(struct net_device *netdev,
 	data[i++] = priv->page_alloc_fail;
 	data[i++] = priv->dma_mapping_error;
 	data[i++] = priv->stats_report_trigger_cnt;
-	data[i++] = priv->ptp_precise_xtstamps;
-	data[i++] = priv->ptp_fallback_xtstamps;
 	i = GVE_MAIN_STATS_LEN;
 
 	rx_base_stats_idx = 0;
@@ -975,7 +972,8 @@ static int gve_get_ts_info(struct net_device *netdev,
 		info->rx_filters |= BIT(HWTSTAMP_FILTER_NONE) |
 				    BIT(HWTSTAMP_FILTER_ALL);
 
-		info->phc_index = ptp_clock_index(priv->ptp->clock);
+		if (priv->ptp)
+			info->phc_index = ptp_clock_index(priv->ptp->clock);
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/google/gve/gve_ptp.c b/drivers/net/ethernet/google/gve/gve_ptp.c
index bc230e68eb1d3..06b1cf4a5efcc 100644
--- a/drivers/net/ethernet/google/gve/gve_ptp.c
+++ b/drivers/net/ethernet/google/gve/gve_ptp.c
@@ -10,261 +10,27 @@
 /* Interval to schedule a nic timestamp calibration, 250ms. */
 #define GVE_NIC_TS_SYNC_INTERVAL_MS 250
 
-/*
- * Stores cycle counter samples in get_cycles() units from a
- * sandwiched NIC clock read
- */
-struct gve_sysclock_sample {
-	/* Cycle counter from NIC before clock read */
-	u64 nic_pre_cycles;
-	/* Cycle counter from NIC after clock read */
-	u64 nic_post_cycles;
-	/* Cycle counter from host before issuing AQ command */
-	cycles_t host_pre_cycles;
-	/* Cycle counter from host after AQ command returns */
-	cycles_t host_post_cycles;
-};
-
-/*
- * Read NIC clock by issuing the AQ command. The command is subject to
- * rate limiting and may need to be retried. Requires nic_ts_read_lock
- * to be held.
- */
-static int gve_ptp_read_timestamp(struct gve_ptp *ptp, cycles_t *pre_cycles,
-				  cycles_t *post_cycles)
-{
-	unsigned long deadline = jiffies + msecs_to_jiffies(100);
-	unsigned long delay_us = 1000;
-	int err;
-
-	lockdep_assert_held(&ptp->nic_ts_read_lock);
-
-	do {
-		*pre_cycles = get_cycles();
-		err = gve_adminq_report_nic_ts(ptp->priv,
-					       ptp->nic_ts_report_bus);
-
-		/* Prevent get_cycles() from being speculatively executed
-		 * before the AdminQ command
-		 */
-		rmb();
-		*post_cycles = get_cycles();
-		if (likely(err != -EAGAIN))
-			return err;
-
-		fsleep(delay_us);
-
-		/* Exponential backoff */
-		delay_us *= 2;
-	} while (time_before(jiffies, deadline));
-
-	return -ETIMEDOUT;
-}
-
 /* Read the nic timestamp from hardware via the admin queue. */
-static int gve_clock_nic_ts_read(struct gve_ptp *ptp, u64 *nic_raw,
-				 struct gve_sysclock_sample *sysclock)
-{
-	cycles_t host_pre_cycles, host_post_cycles;
-	struct gve_nic_ts_report *ts_report;
-	int err;
-
-	mutex_lock(&ptp->nic_ts_read_lock);
-	err = gve_ptp_read_timestamp(ptp, &host_pre_cycles, &host_post_cycles);
-	if (err) {
-		dev_err_ratelimited(&ptp->priv->pdev->dev,
-				    "AdminQ timestamp read failed: %d\n", err);
-		goto out;
-	}
-
-	ts_report = ptp->nic_ts_report;
-	*nic_raw = be64_to_cpu(ts_report->nic_timestamp);
-
-	if (sysclock) {
-		sysclock->nic_pre_cycles = be64_to_cpu(ts_report->pre_cycles);
-		sysclock->nic_post_cycles = be64_to_cpu(ts_report->post_cycles);
-		sysclock->host_pre_cycles = host_pre_cycles;
-		sysclock->host_post_cycles = host_post_cycles;
-	}
-
-out:
-	mutex_unlock(&ptp->nic_ts_read_lock);
-	return err;
-}
-
-struct gve_cycles_to_clock_callback_ctx {
-	u64 cycles;
-};
-
-static int gve_cycles_to_clock_fn(ktime_t *device_time,
-				  struct system_counterval_t *system_counterval,
-				  void *ctx)
+int gve_clock_nic_ts_read(struct gve_priv *priv)
 {
-	struct gve_cycles_to_clock_callback_ctx *context = ctx;
-
-	*device_time = 0;
-
-	system_counterval->cycles = context->cycles;
-	system_counterval->use_nsecs = false;
-
-	if (IS_ENABLED(CONFIG_X86))
-		system_counterval->cs_id = CSID_X86_TSC;
-	else if (IS_ENABLED(CONFIG_ARM64))
-		system_counterval->cs_id = CSID_ARM_ARCH_COUNTER;
-	else
-		return -EOPNOTSUPP;
-
-	return 0;
-}
-
-/*
- * Convert a raw cycle count (e.g. from get_cycles()) to the system clock
- * type specified by clockid. The system_time_snapshot must be taken before
- * the cycle counter is sampled.
- */
-static int gve_cycles_to_timespec64(struct gve_priv *priv, clockid_t clockid,
-				    struct system_time_snapshot *snap,
-				    u64 cycles, struct timespec64 *ts)
-{
-	struct gve_cycles_to_clock_callback_ctx ctx = {0};
-	struct system_device_crosststamp xtstamp;
+	u64 nic_raw;
 	int err;
 
-	ctx.cycles = cycles;
-	err = get_device_system_crosststamp(gve_cycles_to_clock_fn, &ctx, snap,
-					    &xtstamp);
-	if (err) {
-		dev_err_ratelimited(&priv->pdev->dev,
-				    "get_device_system_crosststamp() failed to convert %llu cycles to system time: %d\n",
-				    cycles,
-				    err);
+	err = gve_adminq_report_nic_ts(priv, priv->nic_ts_report_bus);
+	if (err)
 		return err;
-	}
 
-	switch (clockid) {
-	case CLOCK_REALTIME:
-		*ts = ktime_to_timespec64(xtstamp.sys_realtime);
-		break;
-	case CLOCK_MONOTONIC_RAW:
-		*ts = ktime_to_timespec64(xtstamp.sys_monoraw);
-		break;
-	default:
-		dev_err_ratelimited(&priv->pdev->dev,
-				    "Cycle count conversion to clockid %d not supported\n",
-				    clockid);
-		return -EOPNOTSUPP;
-	}
+	nic_raw = be64_to_cpu(priv->nic_ts_report->nic_timestamp);
+	WRITE_ONCE(priv->last_sync_nic_counter, nic_raw);
 
 	return 0;
 }
 
-static bool
-gve_can_use_system_ts_from_device(enum clocksource_ids system_clock_source,
-				  clockid_t clockid)
-{
-	if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC_RAW)
-		return false;
-
-	/* If the system clock source matches the system clock
-	 * returned by the AdminQ command, we can use the system
-	 * timestamps returned by the device, otherwise we have to
-	 * fall back to sampling system time from the host which
-	 * is less accurate.
-	 */
-	if (IS_ENABLED(CONFIG_X86))
-		return system_clock_source == CSID_X86_TSC;
-	else if (IS_ENABLED(CONFIG_ARM64))
-		return system_clock_source == CSID_ARM_ARCH_COUNTER;
-
-	return false;
-}
-
-static int gve_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
-{
-	return -EOPNOTSUPP;
-}
-
-static int gve_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
-{
-	return -EOPNOTSUPP;
-}
-
 static int gve_ptp_gettimex64(struct ptp_clock_info *info,
 			      struct timespec64 *ts,
 			      struct ptp_system_timestamp *sts)
 {
-	struct gve_ptp *ptp = container_of(info, struct gve_ptp, info);
-	struct gve_sysclock_sample sysclock = {0};
-	bool use_system_ts_from_device = false;
-	struct gve_priv *priv = ptp->priv;
-	struct system_time_snapshot snap;
-	u64 nic_ts;
-	int err;
-
-	if (sts) {
-		/* This snapshot is used both to query the current system
-		 * clocksource and to convert the cycle counts returned
-		 * by the AdminQ command to ktime. It does not need to be
-		 * taken inside the retry loop because retries and lock
-		 * contention are expected to be extremely rare.
-		 *
-		 * If the system clock source changes between here and
-		 * when get_device_system_crosststamp() is called,
-		 * get_device_system_crosststamp() will fail which will
-		 * cause one failed sample, and the next one will succeed.
-		 */
-		ktime_get_snapshot(&snap);
-		use_system_ts_from_device =
-			gve_can_use_system_ts_from_device(snap.cs_id,
-							  sts->clockid);
-		if (use_system_ts_from_device)
-			priv->ptp_precise_xtstamps++;
-		else
-			priv->ptp_fallback_xtstamps++;
-	}
-
-	if (unlikely(!use_system_ts_from_device))
-		ptp_read_system_prets(sts);
-
-	err = gve_clock_nic_ts_read(ptp, &nic_ts, sts ? &sysclock : NULL);
-	if (err)
-		return err;
-
-	if (unlikely(!use_system_ts_from_device))
-		ptp_read_system_postts(sts);
-
-	if (sts && likely(use_system_ts_from_device)) {
-		/* Reject samples with out of order system clock values.
-		 * Firmware must return valid non-zero cycle counts.
-		 */
-		if (!(sysclock.host_pre_cycles <= sysclock.nic_pre_cycles &&
-		      sysclock.nic_pre_cycles  <= sysclock.nic_post_cycles &&
-		      sysclock.nic_post_cycles <= sysclock.host_post_cycles)) {
-			dev_err_ratelimited(&priv->pdev->dev,
-					    "AdminQ system clock cycle counts out of order. Expecting %llu <= %llu <= %llu <= %llu\n",
-					    (u64)sysclock.host_pre_cycles,
-					    sysclock.nic_pre_cycles,
-					    sysclock.nic_post_cycles,
-					    (u64)sysclock.host_post_cycles);
-			return -EBADMSG;
-		}
-
-		err = gve_cycles_to_timespec64(priv, sts->clockid, &snap,
-					       sysclock.nic_pre_cycles,
-					       &sts->pre_ts);
-		if (err)
-			return err;
-
-		err = gve_cycles_to_timespec64(priv, sts->clockid, &snap,
-					       sysclock.nic_post_cycles,
-					       &sts->post_ts);
-		if (err)
-			return err;
-	}
-
-	*ts = ns_to_timespec64(nic_ts);
-
-	return 0;
+	return -EOPNOTSUPP;
 }
 
 static int gve_ptp_settime64(struct ptp_clock_info *info,
@@ -275,21 +41,17 @@ static int gve_ptp_settime64(struct ptp_clock_info *info,
 
 static long gve_ptp_do_aux_work(struct ptp_clock_info *info)
 {
-	struct gve_ptp *ptp = container_of(info, struct gve_ptp, info);
+	const struct gve_ptp *ptp = container_of(info, struct gve_ptp, info);
 	struct gve_priv *priv = ptp->priv;
-	u64 nic_raw;
 	int err;
 
 	if (gve_get_reset_in_progress(priv) || !gve_get_admin_queue_ok(priv))
 		goto out;
 
-	err = gve_clock_nic_ts_read(ptp, &nic_raw, NULL);
-	if (err) {
-		dev_err_ratelimited(&priv->pdev->dev, "%s read err %d\n",
-				    __func__, err);
-		goto out;
-	}
-	WRITE_ONCE(priv->last_sync_nic_counter, nic_raw);
+	err = gve_clock_nic_ts_read(priv);
+	if (err && net_ratelimit())
+		dev_err(&priv->pdev->dev,
+			"%s read err %d\n", __func__, err);
 
 out:
 	return msecs_to_jiffies(GVE_NIC_TS_SYNC_INTERVAL_MS);
@@ -298,78 +60,99 @@ out:
 static const struct ptp_clock_info gve_ptp_caps = {
 	.owner          = THIS_MODULE,
 	.name		= "gve clock",
-	.adjfine	= gve_ptp_adjfine,
-	.adjtime	= gve_ptp_adjtime,
 	.gettimex64	= gve_ptp_gettimex64,
 	.settime64	= gve_ptp_settime64,
 	.do_aux_work	= gve_ptp_do_aux_work,
 };
 
-int gve_init_clock(struct gve_priv *priv)
+static int gve_ptp_init(struct gve_priv *priv)
 {
 	struct gve_ptp *ptp;
-	u64 nic_raw;
 	int err;
 
-	ptp = kzalloc_obj(*priv->ptp);
-	if (!ptp)
+	priv->ptp = kzalloc_obj(*priv->ptp);
+	if (!priv->ptp)
 		return -ENOMEM;
 
+	ptp = priv->ptp;
 	ptp->info = gve_ptp_caps;
-	ptp->priv = priv;
-	mutex_init(&ptp->nic_ts_read_lock);
-	ptp->nic_ts_report =
-		dma_alloc_coherent(&priv->pdev->dev,
-				   sizeof(struct gve_nic_ts_report),
-				   &ptp->nic_ts_report_bus, GFP_KERNEL);
-	if (!ptp->nic_ts_report) {
-		dev_err(&priv->pdev->dev, "%s dma alloc error\n", __func__);
-		err = -ENOMEM;
-		goto free_ptp;
-	}
-
-	err = gve_clock_nic_ts_read(ptp, &nic_raw, NULL);
-	if (err) {
-		dev_err(&priv->pdev->dev, "failed to read NIC clock %d\n", err);
-		goto free_dma_mem;
-	}
-	WRITE_ONCE(priv->last_sync_nic_counter, nic_raw);
-
 	ptp->clock = ptp_clock_register(&ptp->info, &priv->pdev->dev);
+
 	if (IS_ERR(ptp->clock)) {
 		dev_err(&priv->pdev->dev, "PTP clock registration failed\n");
-		err = PTR_ERR(ptp->clock);
-		goto free_dma_mem;
+		err  = PTR_ERR(ptp->clock);
+		goto free_ptp;
 	}
 
-	priv->ptp = ptp;
-	ptp_schedule_worker(ptp->clock,
-			    msecs_to_jiffies(GVE_NIC_TS_SYNC_INTERVAL_MS));
-
+	ptp->priv = priv;
 	return 0;
 
-free_dma_mem:
-	dma_free_coherent(&priv->pdev->dev, sizeof(struct gve_nic_ts_report),
-			  ptp->nic_ts_report, ptp->nic_ts_report_bus);
-	ptp->nic_ts_report = NULL;
 free_ptp:
-	mutex_destroy(&ptp->nic_ts_read_lock);
 	kfree(ptp);
+	priv->ptp = NULL;
 	return err;
 }
 
-void gve_teardown_clock(struct gve_priv *priv)
+static void gve_ptp_release(struct gve_priv *priv)
 {
 	struct gve_ptp *ptp = priv->ptp;
 
 	if (!ptp)
 		return;
 
-	priv->ptp = NULL;
-	ptp_clock_unregister(ptp->clock);
-	dma_free_coherent(&priv->pdev->dev, sizeof(struct gve_nic_ts_report),
-			  ptp->nic_ts_report, ptp->nic_ts_report_bus);
-	ptp->nic_ts_report = NULL;
-	mutex_destroy(&ptp->nic_ts_read_lock);
+	if (ptp->clock)
+		ptp_clock_unregister(ptp->clock);
+
 	kfree(ptp);
+	priv->ptp = NULL;
+}
+
+int gve_init_clock(struct gve_priv *priv)
+{
+	int err;
+
+	err = gve_ptp_init(priv);
+	if (err)
+		return err;
+
+	priv->nic_ts_report =
+		dma_alloc_coherent(&priv->pdev->dev,
+				   sizeof(struct gve_nic_ts_report),
+				   &priv->nic_ts_report_bus,
+				   GFP_KERNEL);
+	if (!priv->nic_ts_report) {
+		dev_err(&priv->pdev->dev, "%s dma alloc error\n", __func__);
+		err = -ENOMEM;
+		goto release_ptp;
+	}
+	err = gve_clock_nic_ts_read(priv);
+	if (err) {
+		dev_err(&priv->pdev->dev, "failed to read NIC clock %d\n", err);
+		goto release_nic_ts_report;
+	}
+	ptp_schedule_worker(priv->ptp->clock,
+			    msecs_to_jiffies(GVE_NIC_TS_SYNC_INTERVAL_MS));
+
+	return 0;
+
+release_nic_ts_report:
+	dma_free_coherent(&priv->pdev->dev,
+			  sizeof(struct gve_nic_ts_report),
+			  priv->nic_ts_report, priv->nic_ts_report_bus);
+	priv->nic_ts_report = NULL;
+release_ptp:
+	gve_ptp_release(priv);
+	return err;
+}
+
+void gve_teardown_clock(struct gve_priv *priv)
+{
+	gve_ptp_release(priv);
+
+	if (priv->nic_ts_report) {
+		dma_free_coherent(&priv->pdev->dev,
+				  sizeof(struct gve_nic_ts_report),
+				  priv->nic_ts_report, priv->nic_ts_report_bus);
+		priv->nic_ts_report = NULL;
+	}
 }