This is a note to let you know that I've just added the patch titled
net: fec: ptp: avoid register access when ipg clock is disabled
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fec-ptp-avoid-register-access-when-ipg-clock-is-.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4a9223f09721e5d4837bc23c5fc94d6c24d4a44a
Author: Heiko Thiery <heiko.thiery@xxxxxxxxx>
Date: Thu Feb 25 22:15:16 2021 +0100
net: fec: ptp: avoid register access when ipg clock is disabled
[ Upstream commit 6a4d7234ae9a3bb31181f348ade9bbdb55aeb5c5 ]
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@xxxxxxxxx>
Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210225211514.9115-1-heiko.thiery@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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);
