| Message ID | 20210225211514.9115-1-heiko.thiery@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/1] net: fec: ptp: avoid register access when ipg clock is disabled | expand |
On Thu, Feb 25, 2021 at 10:15:16PM +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.thiery@gmail.com> > --- > v2: > - add mutex (thanks to Richard) > > v3: > I did a mistake and did not test properly > - add parenteses > - fix the used variable Acked-by: Richard Cochran <richardcochran@gmail.com>
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index 2e344aada4c6..1753807cbf97 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -377,9 +377,16 @@ static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) u64 ns; unsigned long flags; + mutex_lock(&adapter->ptp_clk_mutex); + /* Check the ptp clock */ + if (!adapter->ptp_clk_on) { + mutex_unlock(&adapter->ptp_clk_mutex); + return -EINVAL; + } spin_lock_irqsave(&adapter->tmreg_lock, flags); ns = timecounter_read(&adapter->tc); spin_unlock_irqrestore(&adapter->tmreg_lock, flags); + mutex_unlock(&adapter->ptp_clk_mutex); *ts = ns_to_timespec64(ns);
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.thiery@gmail.com> --- v2: - add mutex (thanks to Richard) v3: I did a mistake and did not test properly - add parenteses - fix the used variable drivers/net/ethernet/freescale/fec_ptp.c | 7 +++++++ 1 file changed, 7 insertions(+)