From f707347b33feebdd67633bccea52f96807c18d6e Mon Sep 17 00:00:00 2001 From: Alex Austin Date: Mon, 26 Oct 2026 12:30:22 +0000 Subject: [PATCH] sfc: ptp: serialize host and MC synchronization transactions efx_ptp_synchronize() clears the MC-ready DMA flag before efx_mcdi_rpc_start() acquires the MCDI interface, and processes results into ptp->timeset[] after efx_mcdi_rpc_finish() has released it. The PPS worker and the hwtstamp enable path can therefore clobber each other's handshake flag and timesets. Hold a PHC mutex across the whole transaction and over the clock operations, so efx_phc_settime() reads and adjusts atomically and current_adjfreq is consistently read and written under one lock. Also bail out when efx_mcdi_rpc_start() fails rather than finishing an RPC that was never acquired. Fixes: 7c236c43b838 ("sfc: Add support for IEEE-1588 PTP") Signed-off-by: Alex Austin Reviewed-by: Alejandro Lucero Reviewed-by: Pieter Jansen van Vuuren Acked-by: Edward Cree Link: https://patch.msgid.link/20261026123023.3566549-3-alex.austin@amd.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/sfc/ptp.c | 81 +++++++++++++++++++++++----------- 1 file changed, 55 insertions(+), 26 deletions(-) diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c index 957ca08092e7..e26269fae38d 100644 --- a/drivers/net/ethernet/sfc/ptp.c +++ b/drivers/net/ethernet/sfc/ptp.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include #include "net_driver.h" @@ -271,6 +272,8 @@ struct efx_ptp_rxfilter { * frequency adjustment into a fixed point fractional nanosecond format. * @current_adjfreq: Current ppb adjustment. * @phc_clock: Pointer to registered phc device (if primary function) + * @phc_lock: Serializes PHC commands and synchronization, and protects + * @current_adjfreq * @phc_clock_info: Registration structure for phc device * @pps_work: pps work task for handling pps events * @pps_workwq: pps work queue @@ -330,6 +333,7 @@ struct efx_ptp_data { unsigned int adjfreq_ppb_shift; s64 current_adjfreq; struct ptp_clock *phc_clock; + struct mutex phc_lock; struct ptp_clock_info phc_clock_info; struct work_struct pps_work; struct workqueue_struct *pps_workwq; @@ -1007,7 +1011,14 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf), return 0; } -/* Synchronize times between the host and the MC */ +/* Synchronize times between the host and the MC. + * + * The MC serializes PTP requests, so MC_CMD_PTP_OP_ADJUST cannot be applied + * while MC_CMD_PTP_OP_SYNCHRONIZE is collecting timesets. This holds across + * functions of a controller, which share the clock but adjust it only through + * the function that registered it, so a secondary function can capture here + * without serializing against the primary. + */ static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings) { struct efx_ptp_data *ptp = efx->ptp_data; @@ -1026,11 +1037,14 @@ static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings) MCDI_SET_QWORD(synch_buf, PTP_IN_SYNCHRONIZE_START_ADDR, ptp->start.dma_addr); + mutex_lock(&ptp->phc_lock); + /* Clear flag that signals MC ready */ WRITE_ONCE(*start, 0); rc = efx_mcdi_rpc_start(efx, MC_CMD_PTP, synch_buf, MC_CMD_PTP_IN_SYNCHRONIZE_LEN); - EFX_WARN_ON_ONCE_PARANOID(rc); + if (rc) + goto out; /* Wait for start from MCDI (or timeout) */ timeout = jiffies + msecs_to_jiffies(MAX_SYNCHRONISE_WAIT_MS); @@ -1061,11 +1075,13 @@ static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings) ++ptp->no_time_syncs; } +out: /* Increment the bad syncs counter if the synchronize fails, whatever * the reason. */ if (rc != 0) ++ptp->bad_syncs; + mutex_unlock(&ptp->phc_lock); return rc; } @@ -1568,6 +1584,7 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel) if (!efx->ptp_data) return -ENOMEM; + mutex_init(&ptp->phc_lock); ptp->efx = efx; ptp->channel = channel; @@ -1639,6 +1656,7 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel) efx_nic_free_buffer(efx, &ptp->start); fail1: + mutex_destroy(&ptp->phc_lock); kfree(efx->ptp_data); efx->ptp_data = NULL; @@ -1693,6 +1711,7 @@ void efx_ptp_remove(struct efx_nic *efx) destroy_workqueue(efx->ptp_data->workwq); efx_nic_free_buffer(efx, &efx->ptp_data->start); + mutex_destroy(&efx->ptp_data->phc_lock); kfree(efx->ptp_data); efx->ptp_data = NULL; } @@ -2104,23 +2123,23 @@ static int efx_phc_adjfine(struct ptp_clock_info *ptp, long scaled_ppm) MCDI_SET_QWORD(inadj, PTP_IN_ADJUST_FREQ, adjustment_ns); MCDI_SET_DWORD(inadj, PTP_IN_ADJUST_SECONDS, 0); MCDI_SET_DWORD(inadj, PTP_IN_ADJUST_NANOSECONDS, 0); + mutex_lock(&ptp_data->phc_lock); rc = efx_mcdi_rpc(efx, MC_CMD_PTP, inadj, sizeof(inadj), NULL, 0, NULL); - if (rc != 0) - return rc; - - ptp_data->current_adjfreq = adjustment_ns; - return 0; + if (!rc) + ptp_data->current_adjfreq = adjustment_ns; + mutex_unlock(&ptp_data->phc_lock); + return rc; } -static int efx_phc_adjtime(struct ptp_clock_info *ptp, s64 delta) +static int _efx_phc_adjtime(struct efx_ptp_data *ptp_data, s64 delta) + __must_hold(&ptp_data->phc_lock) { - u32 nic_major, nic_minor; - struct efx_ptp_data *ptp_data = container_of(ptp, - struct efx_ptp_data, - phc_clock_info); - struct efx_nic *efx = ptp_data->efx; MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_ADJUST_LEN); + struct efx_nic *efx = ptp_data->efx; + u32 nic_major, nic_minor; + + lockdep_assert_held(&ptp_data->phc_lock); efx->ptp_data->ns_to_nic_time(delta, &nic_major, &nic_minor); @@ -2133,6 +2152,18 @@ static int efx_phc_adjtime(struct ptp_clock_info *ptp, s64 delta) NULL, 0, NULL); } +static int efx_phc_adjtime(struct ptp_clock_info *ptp, s64 delta) +{ + struct efx_ptp_data *ptp_data = container_of(ptp, struct efx_ptp_data, + phc_clock_info); + int rc; + + mutex_lock(&ptp_data->phc_lock); + rc = _efx_phc_adjtime(ptp_data, delta); + mutex_unlock(&ptp_data->phc_lock); + return rc; +} + static int efx_phc_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) { struct efx_ptp_data *ptp_data = container_of(ptp, @@ -2164,23 +2195,21 @@ static int efx_phc_settime(struct ptp_clock_info *ptp, { /* Get the current NIC time, efx_phc_gettime. * Subtract from the desired time to get the offset - * call efx_phc_adjtime with the offset + * call _efx_phc_adjtime with the offset */ + struct efx_ptp_data *ptp_data = container_of(ptp, struct efx_ptp_data, + phc_clock_info); + struct timespec64 time_now, delta; int rc; - struct timespec64 time_now; - struct timespec64 delta; + mutex_lock(&ptp_data->phc_lock); rc = efx_phc_gettime(ptp, &time_now); - if (rc != 0) - return rc; - - delta = timespec64_sub(*e_ts, time_now); - - rc = efx_phc_adjtime(ptp, timespec64_to_ns(&delta)); - if (rc != 0) - return rc; - - return 0; + if (!rc) { + delta = timespec64_sub(*e_ts, time_now); + rc = _efx_phc_adjtime(ptp_data, timespec64_to_ns(&delta)); + } + mutex_unlock(&ptp_data->phc_lock); + return rc; } static int efx_phc_enable(struct ptp_clock_info *ptp,