netdev - RE: [RFC PATCH 4/4] ixgbe: add support for extended PHC gettime

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Date:   Fri, 26 Oct 2018 16:54:57 +0000
From:   "Keller, Jacob E" <jacob.e.keller@...el.com>
To:     Miroslav Lichvar <mlichvar@...hat.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
        Richard Cochran <richardcochran@...il.com>
Subject: RE: [RFC PATCH 4/4] ixgbe: add support for extended PHC gettime



> -----Original Message-----
> From: Miroslav Lichvar [mailto:mlichvar@...hat.com]
> Sent: Friday, October 26, 2018 9:28 AM
> To: netdev@...r.kernel.org
> Cc: intel-wired-lan@...ts.osuosl.org; Richard Cochran <richardcochran@...il.com>;
> Keller, Jacob E <jacob.e.keller@...el.com>; Miroslav Lichvar <mlichvar@...hat.com>
> Subject: [RFC PATCH 4/4] ixgbe: add support for extended PHC gettime
> 
> Cc: Richard Cochran <richardcochran@...il.com>
> Cc: Jacob Keller <jacob.e.keller@...el.com>
> Signed-off-by: Miroslav Lichvar <mlichvar@...hat.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | 57 ++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
> b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
> index b3e0d8bb5cbd..d31e8d3effc7 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
> @@ -466,6 +466,60 @@ static int ixgbe_ptp_gettime(struct ptp_clock_info *ptp,
> struct timespec64 *ts)
>  	return 0;
>  }
> 
> +/**
> + * ixgbe_ptp_gettimex
> + * @ptp: the ptp clock structure
> + * @sts: structure to hold the system time before reading the PHC,
> + * the PHC timestamp, and system time after reading the PHC
> + *
> + * read the timecounter and return the correct value on ns,
> + * after converting it into a struct timespec.
> + */
> +static int ixgbe_ptp_gettimex(struct ptp_clock_info *ptp,
> +			      struct ptp_system_timestamp *sts)
> +{
> +	struct ixgbe_adapter *adapter =
> +		container_of(ptp, struct ixgbe_adapter, ptp_caps);
> +	struct ixgbe_hw *hw = &adapter->hw;
> +	unsigned long flags;
> +	struct timespec64 ts;
> +	u64 ns, stamp;
> +
> +	spin_lock_irqsave(&adapter->tmreg_lock, flags);
> +
> +	switch (adapter->hw.mac.type) {
> +	case ixgbe_mac_X550:
> +	case ixgbe_mac_X550EM_x:
> +	case ixgbe_mac_x550em_a:
> +		/* Upper 32 bits represent billions of cycles, lower 32 bits
> +		 * represent cycles. However, we use timespec64_to_ns for the
> +		 * correct math even though the units haven't been corrected
> +		 * yet.
> +		 */
> +		ptp_read_system_prets(sts);
> +		IXGBE_READ_REG(hw, IXGBE_SYSTIMR);
> +		ptp_read_system_postts(sts);
> +		ts.tv_nsec = IXGBE_READ_REG(hw, IXGBE_SYSTIML);
> +		ts.tv_sec = IXGBE_READ_REG(hw, IXGBE_SYSTIMH);
> +		stamp = timespec64_to_ns(&ts);
> +		break;
> +	default:
> +		ptp_read_system_prets(sts);
> +		stamp = IXGBE_READ_REG(hw, IXGBE_SYSTIML);
> +		ptp_read_system_postts(sts);
> +		stamp |= (u64)IXGBE_READ_REG(hw, IXGBE_SYSTIMH) << 32;
> +		break;
> +	}
> +
> +	ns = timecounter_cyc2time(&adapter->hw_tc, stamp);
> +
> +	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
> +
> +	sts->phc_ts = ns_to_timespec64(ns);
> +
> +	return 0;
> +}
> +


What about replacing gettime64 with:

static int ixgbe_ptp_gettimex(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
    struct ptp_system_timestamp sts
    
    ixgbe_ptp_gettimex(ptp, &tst);
    *ts = sts.phc_ts
}

Actually, could that even just be provided by the PTP core if gettime64 isn't implemented? This way new drivers only have to implement the new interface, and userspace will just get the old behavior if they use the old call?

Thanks,
Jake

>  /**
>   * ixgbe_ptp_settime
>   * @ptp: the ptp clock structure
> @@ -1217,6 +1271,7 @@ static long ixgbe_ptp_create_clock(struct ixgbe_adapter
> *adapter)
>  		adapter->ptp_caps.adjfreq = ixgbe_ptp_adjfreq_82599;
>  		adapter->ptp_caps.adjtime = ixgbe_ptp_adjtime;
>  		adapter->ptp_caps.gettime64 = ixgbe_ptp_gettime;
> +		adapter->ptp_caps.gettimex64 = ixgbe_ptp_gettimex;
>  		adapter->ptp_caps.settime64 = ixgbe_ptp_settime;
>  		adapter->ptp_caps.enable = ixgbe_ptp_feature_enable;
>  		adapter->ptp_setup_sdp = ixgbe_ptp_setup_sdp_x540;
> @@ -1234,6 +1289,7 @@ static long ixgbe_ptp_create_clock(struct ixgbe_adapter
> *adapter)
>  		adapter->ptp_caps.adjfreq = ixgbe_ptp_adjfreq_82599;
>  		adapter->ptp_caps.adjtime = ixgbe_ptp_adjtime;
>  		adapter->ptp_caps.gettime64 = ixgbe_ptp_gettime;
> +		adapter->ptp_caps.gettimex64 = ixgbe_ptp_gettimex;
>  		adapter->ptp_caps.settime64 = ixgbe_ptp_settime;
>  		adapter->ptp_caps.enable = ixgbe_ptp_feature_enable;
>  		break;
> @@ -1250,6 +1306,7 @@ static long ixgbe_ptp_create_clock(struct ixgbe_adapter
> *adapter)
>  		adapter->ptp_caps.adjfreq = ixgbe_ptp_adjfreq_X550;
>  		adapter->ptp_caps.adjtime = ixgbe_ptp_adjtime;
>  		adapter->ptp_caps.gettime64 = ixgbe_ptp_gettime;
> +		adapter->ptp_caps.gettimex64 = ixgbe_ptp_gettimex;
>  		adapter->ptp_caps.settime64 = ixgbe_ptp_settime;
>  		adapter->ptp_caps.enable = ixgbe_ptp_feature_enable;
>  		adapter->ptp_setup_sdp = NULL;
> --
> 2.17.2