On Sat, 20 Feb 2021 07:56:55 +0100 Heiko Thiery wrote: > When accessing the timecounter register on an i.MX8MQ the kernel hangs. > This is only the case when the interface is down. This can be reproduced > by reading with 'phc_ctrl eth0 get'. > > Like described in the change in 91c0d987a9788dcc5fe26baafd73bf9242b68900 > the igp clock is disabled when the interface is down and leads to a > system hang. > > So we check if the ptp clock status before reading the timecounter > register. > > Signed-off-by: Heiko Thiery <heiko.thi...@gmail.com>
Please widen the CC list, you should CC Richard on PTP patches. > diff --git a/drivers/net/ethernet/freescale/fec_ptp.c > b/drivers/net/ethernet/freescale/fec_ptp.c > index 2e344aada4c6..c9882083da02 100644 > --- a/drivers/net/ethernet/freescale/fec_ptp.c > +++ b/drivers/net/ethernet/freescale/fec_ptp.c > @@ -377,6 +377,9 @@ static int fec_ptp_gettime(struct ptp_clock_info *ptp, > struct timespec64 *ts) > u64 ns; > unsigned long flags; > > + /* Check the ptp clock */ Comment is rather redundant. Drop it or say _when_ ptp_clk_on may not be true. > + if (!adapter->ptp_clk_on) > + return -EINVAL; Why is the PTP interface registered when it can't be accessed? Perhaps the driver should unregister the PTP clock when it's brought down? > spin_lock_irqsave(&adapter->tmreg_lock, flags); > ns = timecounter_read(&adapter->tc); > spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
