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Commit a4121352 authored by Heiko Thiery's avatar Heiko Thiery Committed by Greg Kroah-Hartman
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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 91c0d987
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: default avatarHeiko Thiery <heiko.thiery@gmail.com>
Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Link: https://lore.kernel.org/r/20210225211514.9115-1-heiko.thiery@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 78fec161

drivers/net/ethernet/freescale/fec_ptp.c

+7 −0
Original line number Diff line number Diff line
@@ -382,9 +382,16 @@ 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);