Re: [PATCH 1/1] net: fec: ptp: avoid register access when ipg clock is disabled
From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-02-23 03:02:12
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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 <redacted>
Please widen the CC list, you should CC Richard on PTP patches.
quoted hunk ↗ jump to hunk
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);