mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-05 16:54:27 +00:00
c51b7bf840
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: Kevin Yang <yyd@google.com> Signed-off-by: John Fraker <jfraker@google.com> Signed-off-by: Tim Hostetler <thostet@google.com> Signed-off-by: Ziwei Xiao <ziweixiao@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com> Link: https://patch.msgid.link/20250614000754.164827-6-hramamurthy@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
139 lines
2.8 KiB
C
139 lines
2.8 KiB
C
// SPDX-License-Identifier: (GPL-2.0 OR MIT)
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/* Google virtual Ethernet (gve) driver
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*
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* Copyright (C) 2025 Google LLC
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*/
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#include "gve.h"
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#include "gve_adminq.h"
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/* Interval to schedule a nic timestamp calibration, 250ms. */
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#define GVE_NIC_TS_SYNC_INTERVAL_MS 250
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/* Read the nic timestamp from hardware via the admin queue. */
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int gve_clock_nic_ts_read(struct gve_priv *priv)
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{
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u64 nic_raw;
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int err;
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err = gve_adminq_report_nic_ts(priv, priv->nic_ts_report_bus);
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if (err)
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return err;
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nic_raw = be64_to_cpu(priv->nic_ts_report->nic_timestamp);
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WRITE_ONCE(priv->last_sync_nic_counter, nic_raw);
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return 0;
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}
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static long gve_ptp_do_aux_work(struct ptp_clock_info *info)
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{
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const struct gve_ptp *ptp = container_of(info, struct gve_ptp, info);
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struct gve_priv *priv = ptp->priv;
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int err;
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if (gve_get_reset_in_progress(priv) || !gve_get_admin_queue_ok(priv))
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goto out;
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err = gve_clock_nic_ts_read(priv);
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if (err && net_ratelimit())
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dev_err(&priv->pdev->dev,
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"%s read err %d\n", __func__, err);
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out:
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return msecs_to_jiffies(GVE_NIC_TS_SYNC_INTERVAL_MS);
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}
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static const struct ptp_clock_info gve_ptp_caps = {
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.owner = THIS_MODULE,
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.name = "gve clock",
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.do_aux_work = gve_ptp_do_aux_work,
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};
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static int gve_ptp_init(struct gve_priv *priv)
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{
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struct gve_ptp *ptp;
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int err;
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if (!priv->nic_timestamp_supported) {
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dev_dbg(&priv->pdev->dev, "Device does not support PTP\n");
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return -EOPNOTSUPP;
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}
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priv->ptp = kzalloc(sizeof(*priv->ptp), GFP_KERNEL);
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if (!priv->ptp)
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return -ENOMEM;
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ptp = priv->ptp;
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ptp->info = gve_ptp_caps;
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ptp->clock = ptp_clock_register(&ptp->info, &priv->pdev->dev);
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if (IS_ERR(ptp->clock)) {
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dev_err(&priv->pdev->dev, "PTP clock registration failed\n");
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err = PTR_ERR(ptp->clock);
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goto free_ptp;
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}
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ptp->priv = priv;
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return 0;
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free_ptp:
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kfree(ptp);
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priv->ptp = NULL;
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return err;
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}
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static void gve_ptp_release(struct gve_priv *priv)
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{
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struct gve_ptp *ptp = priv->ptp;
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if (!ptp)
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return;
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if (ptp->clock)
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ptp_clock_unregister(ptp->clock);
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kfree(ptp);
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priv->ptp = NULL;
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}
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int gve_init_clock(struct gve_priv *priv)
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{
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int err;
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if (!priv->nic_timestamp_supported)
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return 0;
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err = gve_ptp_init(priv);
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if (err)
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return err;
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priv->nic_ts_report =
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dma_alloc_coherent(&priv->pdev->dev,
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sizeof(struct gve_nic_ts_report),
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&priv->nic_ts_report_bus,
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GFP_KERNEL);
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if (!priv->nic_ts_report) {
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dev_err(&priv->pdev->dev, "%s dma alloc error\n", __func__);
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err = -ENOMEM;
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goto release_ptp;
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}
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return 0;
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release_ptp:
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gve_ptp_release(priv);
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return err;
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}
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void gve_teardown_clock(struct gve_priv *priv)
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{
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gve_ptp_release(priv);
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if (priv->nic_ts_report) {
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dma_free_coherent(&priv->pdev->dev,
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sizeof(struct gve_nic_ts_report),
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priv->nic_ts_report, priv->nic_ts_report_bus);
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priv->nic_ts_report = NULL;
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}
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}
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