Commit c51b7bf8 authored by Kevin Yang's avatar Kevin Yang Committed by Jakub Kicinski
Browse files

gve: Add support to query the nic clock 



Query the nic clock and store the results. The timestamp delivered
in descriptors has a wraparound time of ~4 seconds so 250ms is chosen
as the sync cadence to provide a balance between performance, and
drift potential when we do start associating host time and nic time.

Leverage PTP's aux_work to query the nic clock periodically.

Signed-off-by: default avatarKevin Yang <yyd@google.com>
Signed-off-by: default avatarJohn Fraker <jfraker@google.com>
Signed-off-by: default avatarTim Hostetler <thostet@google.com>
Signed-off-by: default avatarZiwei Xiao <ziweixiao@google.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarHarshitha Ramamurthy <hramamurthy@google.com>
Link: https://patch.msgid.link/20250614000754.164827-6-hramamurthy@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 21235ad9

drivers/net/ethernet/google/gve/gve.h

+21 −0
Original line number Diff line number Diff line
@@ -882,6 +882,9 @@ struct gve_priv { 
	/* True if the device supports reading the nic clock */

	bool nic_timestamp_supported;

	struct gve_ptp *ptp;

	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 */

};



enum gve_service_task_flags_bit {
@@ -1261,6 +1264,24 @@ int gve_del_flow_rule(struct gve_priv *priv, struct ethtool_rxnfc *cmd); 
int gve_flow_rules_reset(struct gve_priv *priv);

/* RSS config */

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)

{

	return 0;

}



static inline void gve_teardown_clock(struct gve_priv *priv) { }

#endif /* CONFIG_PTP_1588_CLOCK */

/* report stats handling */

void gve_handle_report_stats(struct gve_priv *priv);

/* exported by ethtool.c */

drivers/net/ethernet/google/gve/gve_main.c

+6 −1
Original line number Diff line number Diff line
@@ -619,9 +619,12 @@ static int gve_setup_device_resources(struct gve_priv *priv) 
	err = gve_alloc_counter_array(priv);

	if (err)

		goto abort_with_rss_config_cache;

	err = gve_alloc_notify_blocks(priv);

	err = gve_init_clock(priv);

	if (err)

		goto abort_with_counter;

	err = gve_alloc_notify_blocks(priv);

	if (err)

		goto abort_with_clock;

	err = gve_alloc_stats_report(priv);

	if (err)

		goto abort_with_ntfy_blocks;
@@ -674,6 +677,8 @@ static int gve_setup_device_resources(struct gve_priv *priv) 
	gve_free_stats_report(priv);

abort_with_ntfy_blocks:

	gve_free_notify_blocks(priv);

abort_with_clock:

	gve_teardown_clock(priv);

abort_with_counter:

	gve_free_counter_array(priv);

abort_with_rss_config_cache:

drivers/net/ethernet/google/gve/gve_ptp.c

+82 −2
Original line number Diff line number Diff line
@@ -5,13 +5,52 @@ 
 */



#include "gve.h"

#include "gve_adminq.h"



/* Interval to schedule a nic timestamp calibration, 250ms. */

#define GVE_NIC_TS_SYNC_INTERVAL_MS 250



/* Read the nic timestamp from hardware via the admin queue. */

int gve_clock_nic_ts_read(struct gve_priv *priv)

{

	u64 nic_raw;

	int err;



	err = gve_adminq_report_nic_ts(priv, priv->nic_ts_report_bus);

	if (err)

		return err;



	nic_raw = be64_to_cpu(priv->nic_ts_report->nic_timestamp);

	WRITE_ONCE(priv->last_sync_nic_counter, nic_raw);



	return 0;

}



static long gve_ptp_do_aux_work(struct ptp_clock_info *info)

{

	const struct gve_ptp *ptp = container_of(info, struct gve_ptp, info);

	struct gve_priv *priv = ptp->priv;

	int err;



	if (gve_get_reset_in_progress(priv) || !gve_get_admin_queue_ok(priv))

		goto out;



	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);

}



static const struct ptp_clock_info gve_ptp_caps = {

	.owner          = THIS_MODULE,

	.name		= "gve clock",

	.do_aux_work	= gve_ptp_do_aux_work,

};



static int __maybe_unused gve_ptp_init(struct gve_priv *priv)

static int gve_ptp_init(struct gve_priv *priv)

{

	struct gve_ptp *ptp;

	int err;
@@ -44,7 +83,7 @@ static int __maybe_unused gve_ptp_init(struct gve_priv *priv) 
	return err;

}



static void __maybe_unused gve_ptp_release(struct gve_priv *priv)

static void gve_ptp_release(struct gve_priv *priv)

{

	struct gve_ptp *ptp = priv->ptp;
@@ -57,3 +96,44 @@ static void __maybe_unused gve_ptp_release(struct gve_priv *priv) 
	kfree(ptp);

	priv->ptp = NULL;

}



int gve_init_clock(struct gve_priv *priv)

{

	int err;



	if (!priv->nic_timestamp_supported)

		return 0;



	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;

	}



	return 0;



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;

	}

}