Re: [PATCH net] net: fec: don't save PTP state if PTP is unsupported

[Csókás Bence]

On 2024. 10. 08. 8:11, Wei Fang wrote:
> Some platforms (such as i.MX25 and i.MX27) do not support PTP, so on
> these platforms fec_ptp_init() is not called and the related members
> in fep are not initialized. However, fec_ptp_save_state() is called
> unconditionally, which causes the kernel to panic. Therefore, add a
> condition so that fec_ptp_save_state() is not called if PTP is not
> supported.
>
> Fixes: a1477dc87dc4 ("net: fec: Restart PPS after link state change")
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Closes: https://lore.kernel.org/lkml/353e41fe-6bb4-4ee9-9980-2da2a9c1c508@xxxxxxxxxxxx/
> Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
> ---
>   drivers/net/ethernet/freescale/fec_main.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 60fb54231ead..1b55047c0237 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1077,7 +1077,8 @@ fec_restart(struct net_device *ndev)
>   	u32 rcntl = OPT_FRAME_SIZE | 0x04;
>   	u32 ecntl = FEC_ECR_ETHEREN;
>   
> -	fec_ptp_save_state(fep);
> +	if (fep->bufdesc_ex)
> +		fec_ptp_save_state(fep);
>   
>   	/* Whack a reset.  We should wait for this.
>   	 * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
> @@ -1340,7 +1341,8 @@ fec_stop(struct net_device *ndev)
>   			netdev_err(ndev, "Graceful transmit stop did not complete!\n");
>   	}
>   
> -	fec_ptp_save_state(fep);
> +	if (fep->bufdesc_ex)
> +		fec_ptp_save_state(fep);
>   
>   	/* Whack a reset.  We should wait for this.
>   	 * For i.MX6SX SOC, enet use AXI bus, we use disable MAC

Thanks, it seems fec_ptp_restore_state() was properly guarded, but 
save_state() was not. Sorry for that.

Reviewed-by: Csókás, Bence <csokas.bence@xxxxxxxxx>