RE: [PATCH net 2/2] net: fec: Reload PTP registers after link-state change

[Wei Fang]

> -----Original Message-----
> From: Csókás, Bence <csokas.bence@xxxxxxxxx>
> Sent: 2024年9月24日 17:37
> To: Frank Li <Frank.Li@xxxxxxxxxxxxx>; David S. Miller
> <davem@xxxxxxxxxxxxx>; imx@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: Csókás, Bence <csokas.bence@xxxxxxxxx>; Wei Fang <wei.fang@xxxxxxx>;
> Shenwei Wang <shenwei.wang@xxxxxxx>; Clark Wang
> <xiaoning.wang@xxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub
> Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Richard
> Cochran <richardcochran@xxxxxxxxx>
> Subject: [PATCH net 2/2] net: fec: Reload PTP registers after link-state change
> 
> On link-state change, the controller gets reset,
> which clears all PTP registers, including PHC time,
> calibrated clock correction values etc. For correct
> IEEE 1588 operation we need to restore these after
> the reset.
> 
> Fixes: 6605b730c061 ("FEC: Add time stamping code and a PTP hardware
> clock")
> Signed-off-by: Csókás, Bence <csokas.bence@xxxxxxxxx>
> ---
>  drivers/net/ethernet/freescale/fec.h     |  3 +++
>  drivers/net/ethernet/freescale/fec_ptp.c | 20 ++++++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/drivers/net/ethernet/freescale/fec.h
> b/drivers/net/ethernet/freescale/fec.h
> index 0552317a2554..1cca0425d493 100644
> --- a/drivers/net/ethernet/freescale/fec.h
> +++ b/drivers/net/ethernet/freescale/fec.h
> @@ -693,6 +693,9 @@ struct fec_enet_private {
> 
>  	struct {
>  		int pps_enable;
> +		u64 ns_sys, ns_phc;
> +		u32 at_corr;
> +		u8 at_inc_corr;
>  	} ptp_saved_state;
> 
>  	u64 ethtool_stats[];
> diff --git a/drivers/net/ethernet/freescale/fec_ptp.c
> b/drivers/net/ethernet/freescale/fec_ptp.c
> index df1ef023493b..a4eb6edb850a 100644
> --- a/drivers/net/ethernet/freescale/fec_ptp.c
> +++ b/drivers/net/ethernet/freescale/fec_ptp.c
> @@ -767,24 +767,44 @@ void fec_ptp_init(struct platform_device *pdev, int
> irq_idx)
>  void fec_ptp_save_state(struct fec_enet_private *fep)
>  {
>  	unsigned long flags;
> +	u32 atime_inc_corr;
> 
>  	spin_lock_irqsave(&fep->tmreg_lock, flags);
> 
>  	fep->ptp_saved_state.pps_enable = fep->pps_enable;
> 
> +	fep->ptp_saved_state.ns_phc = timecounter_read(&fep->tc);
> +	fep->ptp_saved_state.ns_sys = ktime_get_ns();
> +
> +	fep->ptp_saved_state.at_corr = readl(fep->hwp + FEC_ATIME_CORR);
> +	atime_inc_corr = readl(fep->hwp + FEC_ATIME_INC) &
> FEC_T_INC_CORR_MASK;
> +	fep->ptp_saved_state.at_inc_corr = (u8)(atime_inc_corr >>
> FEC_T_INC_CORR_OFFSET);
> +
>  	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
>  }
> 
>  /* Restore PTP functionality after a reset */
>  void fec_ptp_restore_state(struct fec_enet_private *fep)
>  {
> +	u32 atime_inc = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
>  	unsigned long flags;
> +	u32 counter;
> +	u64 ns;
> 
>  	spin_lock_irqsave(&fep->tmreg_lock, flags);
> 
>  	/* Reset turned it off, so adjust our status flag */
>  	fep->pps_enable = 0;
> 
> +	writel(fep->ptp_saved_state.at_corr, fep->hwp + FEC_ATIME_CORR);
> +	atime_inc |= ((u32)fep->ptp_saved_state.at_inc_corr) <<
> FEC_T_INC_CORR_OFFSET;
> +	writel(atime_inc, fep->hwp + FEC_ATIME_INC);
> +
> +	ns = ktime_get_ns() - fep->ptp_saved_state.ns_sys +
> fep->ptp_saved_state.ns_phc;
> +	counter = ns & fep->cc.mask;
> +	writel(counter, fep->hwp + FEC_ATIME);
> +	timecounter_init(&fep->tc, &fep->cc, ns);
> +
>  	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
> 
>  	/* Restart PPS if needed */
> --
> 2.34.1
> 
Thanks,

Reviewed-by: Wei Fang <wei.fang@xxxxxxx>