| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.11 004/254] net: fec: ptp: avoid register access when ipg clock is disabled | Date | Mon, 29 Mar 2021 09:55:20 +0200 |
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From: Heiko Thiery <heiko.thiery@gmail.com>
[ 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@gmail.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Link: https://lore.kernel.org/r/20210225211514.9115-1-heiko.thiery@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/ethernet/freescale/fec_ptp.c | 7 +++++++ 1 file changed, 7 insertions(+)
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); -- 2.30.1
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