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Diffstat (limited to 'drivers/net/ethernet/intel/i40e/i40e_ptp.c')
-rw-r--r--drivers/net/ethernet/intel/i40e/i40e_ptp.c58
1 files changed, 54 insertions, 4 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
index 31575c0bb884..439c35f0c581 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
@@ -725,16 +725,68 @@ static long i40e_ptp_create_clock(struct i40e_pf *pf)
pf->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
pf->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
+ /* Set the previous "reset" time to the current Kernel clock time */
+ pf->ptp_prev_hw_time = ktime_to_timespec64(ktime_get_real());
+ pf->ptp_reset_start = ktime_get();
+
return 0;
}
/**
+ * i40e_ptp_save_hw_time - Save the current PTP time as ptp_prev_hw_time
+ * @pf: Board private structure
+ *
+ * Read the current PTP time and save it into pf->ptp_prev_hw_time. This should
+ * be called at the end of preparing to reset, just before hardware reset
+ * occurs, in order to preserve the PTP time as close as possible across
+ * resets.
+ */
+void i40e_ptp_save_hw_time(struct i40e_pf *pf)
+{
+ /* don't try to access the PTP clock if it's not enabled */
+ if (!(pf->flags & I40E_FLAG_PTP))
+ return;
+
+ i40e_ptp_gettimex(&pf->ptp_caps, &pf->ptp_prev_hw_time, NULL);
+ /* Get a monotonic starting time for this reset */
+ pf->ptp_reset_start = ktime_get();
+}
+
+/**
+ * i40e_ptp_restore_hw_time - Restore the ptp_prev_hw_time + delta to PTP regs
+ * @pf: Board private structure
+ *
+ * Restore the PTP hardware clock registers. We previously cached the PTP
+ * hardware time as pf->ptp_prev_hw_time. To be as accurate as possible,
+ * update this value based on the time delta since the time was saved, using
+ * CLOCK_MONOTONIC (via ktime_get()) to calculate the time difference.
+ *
+ * This ensures that the hardware clock is restored to nearly what it should
+ * have been if a reset had not occurred.
+ */
+void i40e_ptp_restore_hw_time(struct i40e_pf *pf)
+{
+ ktime_t delta = ktime_sub(ktime_get(), pf->ptp_reset_start);
+
+ /* Update the previous HW time with the ktime delta */
+ timespec64_add_ns(&pf->ptp_prev_hw_time, ktime_to_ns(delta));
+
+ /* Restore the hardware clock registers */
+ i40e_ptp_settime(&pf->ptp_caps, &pf->ptp_prev_hw_time);
+}
+
+/**
* i40e_ptp_init - Initialize the 1588 support after device probe or reset
* @pf: Board private structure
*
* This function sets device up for 1588 support. The first time it is run, it
* will create a PHC clock device. It does not create a clock device if one
* already exists. It also reconfigures the device after a reset.
+ *
+ * The first time a clock is created, i40e_ptp_create_clock will set
+ * pf->ptp_prev_hw_time to the current system time. During resets, it is
+ * expected that this timespec will be set to the last known PTP clock time,
+ * in order to preserve the clock time as close as possible across a reset.
**/
void i40e_ptp_init(struct i40e_pf *pf)
{
@@ -766,7 +818,6 @@ void i40e_ptp_init(struct i40e_pf *pf)
dev_err(&pf->pdev->dev, "%s: ptp_clock_register failed\n",
__func__);
} else if (pf->ptp_clock) {
- struct timespec64 ts;
u32 regval;
if (pf->hw.debug_mask & I40E_DEBUG_LAN)
@@ -787,9 +838,8 @@ void i40e_ptp_init(struct i40e_pf *pf)
/* reset timestamping mode */
i40e_ptp_set_timestamp_mode(pf, &pf->tstamp_config);
- /* Set the clock value. */
- ts = ktime_to_timespec64(ktime_get_real());
- i40e_ptp_settime(&pf->ptp_caps, &ts);
+ /* Restore the clock time based on last known value */
+ i40e_ptp_restore_hw_time(pf);
}
}