netdev - Re: [PATCH net-next v2 2/2] ice: ptp: add control over HW timestamp latch point

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Message-ID: <a3e2b0b6-df37-4320-b928-741f360548d3@intel.com>
Date: Tue, 29 Oct 2024 09:21:47 +0100
From: Przemek Kitszel <przemyslaw.kitszel@...el.com>
To: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>
CC: <anthony.l.nguyen@...el.com>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<richardcochran@...il.com>, Aleksandr Loktionov
	<aleksandr.loktionov@...el.com>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <intel-wired-lan@...ts.osuosl.org>
Subject: Re: [PATCH net-next v2 2/2] ice: ptp: add control over HW timestamp
 latch point

On 10/28/24 21:47, Arkadiusz Kubalewski wrote:
> Allow user to control the latch point of ptp HW timestamps in E825

sometimes you write ptp, sometimes PTP, I would make it consistent
(but subject line is fine as is)

> devices.
> 
> Usage, examples:
> 
> ** Obtain current state:
> $ cat /sys/class/net/eth<N>/device/ptp/ts_point
> Command returns enum/integer:
> * 0 - timestamp latched by PHY at the beginning of SFD,
> * 1 - timestamp latched by PHY after the SFD,

perhaps those values could be exported to uAPI?
(the enum from the prev patch)
+enum ptp_ts_point {
+	PTP_TS_POINT_SFD,
+	PTP_TS_POINT_POST_SFD,

> * None - callback returns error to the user.
> 
> ** Configure timestamp latch point at the beginning of SFD:
> $ echo 0 > /sys/class/net/eth<N>/device/ptp/ts_point
> 
> ** Configure timestamp latch point after the SFD:
> $ echo 1 > /sys/class/net/eth<N>/device/ptp/ts_point
> 
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>
> Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>

general ask: for future submissions please use --base switch of
git-send-email, this will aid resolving conflicts or applying the patch
locally for review;

this series in particular would likely conflicts with current
Tony's dev-queue (didn't checked, but Karol removes ice_is_e825c(),
called within 3-line context of your changes).

> ---
> v2:
> - add kernel doc return description on ice_get_ts_point(..),
> - use enum ptp_ts_point directly, instead of additional bool to pass tx
>    timestamp latch point from userspace callback up to ptp_hw
>    configuration,
> - fix bit logic.
> ---
>   drivers/net/ethernet/intel/ice/ice_ptp.c    | 44 +++++++++++++++
>   drivers/net/ethernet/intel/ice/ice_ptp_hw.c | 59 +++++++++++++++++++++
>   drivers/net/ethernet/intel/ice/ice_ptp_hw.h |  2 +
>   3 files changed, 105 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index a999fface272..21fc6b5e2d69 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -2509,6 +2509,48 @@ static int ice_ptp_parse_sdp_entries(struct ice_pf *pf, __le16 *entries,
>   	return 0;
>   }
>   
> +/**
> + * ice_get_ts_point - get the tx timestamp latch point

Tx, please apply in the whole patch

> + * @info: the driver's PTP info structure
> + * @point: return the configured tx timestamp latch point
> + *
> + * Return: 0 on success, negative on failure.
> + */
> +static int
> +ice_get_ts_point(struct ptp_clock_info *info, enum ptp_ts_point *point)

nit: the current preferred style is to break line after "info,"

> +{
> +	struct ice_pf *pf = ptp_info_to_pf(info);
> +	struct ice_hw *hw = &pf->hw;
> +	int ret;
> +
> +	ice_ptp_lock(hw);
> +	ret = ice_ptp_hw_ts_point_get(hw, point);
> +	ice_ptp_unlock(hw);
> +
> +	return ret;
> +}

[...]

> +/**
> + * ice_ptp_hw_ts_point_set - configure timestamping on/post SFD
> + * @hw: pointer to the HW struct
> + * @point: requested tx timestamp latch point
> + *
> + * Configure timestamping to measure at the beginning/post SFD (Start of Frame
> + * Delimiter)
> + *
> + * Return: 0 on success, negative on error
> + */
> +int ice_ptp_hw_ts_point_set(struct ice_hw *hw, enum ptp_ts_point point)
> +{
> +	u8 port = hw->port_info->lport;
> +	int err, val;
> +
> +	err = ice_read_mac_reg_eth56g(hw, port, PHY_MAC_XIF_MODE, &val);
> +	if (err)
> +		return err;
> +	if ((val & PHY_MAC_XIF_TS_SFD_ENA_M && point == PTP_TS_POINT_SFD) ||
> +	    (!(val & PHY_MAC_XIF_TS_SFD_ENA_M) &&
> +	     point == PTP_TS_POINT_POST_SFD))

that's the thing that urged me to start commenting on this patch ;)

put braces around (bit & arith) combined with logical && or ||

you could also split into multiple if branches for readability

> +		return -EINVAL;
> +	if (point == PTP_TS_POINT_SFD)
> +		val |= PHY_MAC_XIF_TS_SFD_ENA_M;
> +	else if (point == PTP_TS_POINT_POST_SFD)
> +		val &= ~PHY_MAC_XIF_TS_SFD_ENA_M;
> +	else
> +		return -EINVAL;
> +
> +	return ice_write_mac_reg_eth56g(hw, port, PHY_MAC_XIF_MODE, val);
> +}
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
> index 656daff3447e..f8e495b82653 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
> @@ -348,6 +348,8 @@ void ice_ptp_init_hw(struct ice_hw *hw);
>   int ice_get_phy_tx_tstamp_ready(struct ice_hw *hw, u8 block, u64 *tstamp_ready);
>   int ice_ptp_one_port_cmd(struct ice_hw *hw, u8 configured_port,
>   			 enum ice_ptp_tmr_cmd configured_cmd);
> +int ice_ptp_hw_ts_point_get(struct ice_hw *hw, enum ptp_ts_point *point);
> +int ice_ptp_hw_ts_point_set(struct ice_hw *hw, enum ptp_ts_point point);
>   
>   /* E822 family functions */
>   int ice_read_quad_reg_e82x(struct ice_hw *hw, u8 quad, u16 offset, u32 *val);