Date: Wed, 23 Aug 2023 13:56:11 -0700
From: Jacob Keller <jacob.e.keller@...el.com>
To: Karol Kolacinski <karol.kolacinski@...el.com>,
	<intel-wired-lan@...ts.osuosl.org>
CC: <netdev@...r.kernel.org>, <anthony.l.nguyen@...el.com>,
	<jesse.brandeburg@...el.com>
Subject: Re: [PATCH v3 iwl-next 4/9] ice: rename PTP functions and fields



On 8/22/2023 5:40 AM, Karol Kolacinski wrote:
> From: Jacob Keller <jacob.e.keller@...el.com>
> 
> The tx->verify_cached flag is used to inform the Tx timestamp tracking
> code whether it needs to verify the cached Tx timestamp value against
> a previous captured value. This is necessary on E810 hardware which does
> not have a Tx timestamp ready bitmap.
> 
> In addition, we currently rely on the fact that the
> ice_get_phy_tx_tstamp_ready() function returns all 1s for E810 hardware.
> Instead of introducing a brand new flag, rename and verify_cached to
> has_ready_bitmap, inverting the relevant checks.
> 
> The ice_ptp_tx_cfg_intr() function sends a control queue message to
> configure the PHY timestamp interrupt block. This is a very similar name
> to a function which is used to configure the MAC Other Interrupt Cause
> Enable register.
> 
> Rename this function to ice_ptp_cfg_phy_interrupt in order to make it
> more obvious to the reader what action it performs, and distinguish it
> from other similarly named functions.
> 
> The ice_ptp_configure_tx_tstamp function writes to PFINT_OICR_ENA to
> configure it with the PFINT_OICR_TX_TSYN_M bit. The name of this
> function is confusing because there are multiple other functions with
> almost identical names.
> 
> Rename it to ice_ptp_cfg_tx_interrupt in order to make it more obvious
> to the reader what action it performs.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
> Signed-off-by: Karol Kolacinski <karol.kolacinski@...el.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_ptp.c | 41 +++++++++++++-----------
>  drivers/net/ethernet/intel/ice/ice_ptp.h |  6 +++-
>  2 files changed, 27 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index bd94b42e19dd..393156b9b426 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -281,11 +281,11 @@ static const char *ice_ptp_state_str(enum ice_ptp_state state)
>  }
>  
>  /**
> - * ice_ptp_configure_tx_tstamp - Enable or disable Tx timestamp interrupt
> - * @pf: The PF pointer to search in
> + * ice_ptp_cfg_tx_interrupt - Configure Tx timestamp interrupt for the device
> + * @pf: Board private structure
>   * @on: bool value for whether timestamp interrupt is enabled or disabled
>   */
> -static void ice_ptp_configure_tx_tstamp(struct ice_pf *pf, bool on)
> +static void ice_ptp_cfg_tx_interrupt(struct ice_pf *pf, bool on)
>  {
>  	u32 val;
>  
> @@ -320,7 +320,7 @@ static void ice_set_tx_tstamp(struct ice_pf *pf, bool on)
>  	}
>  
>  	if (pf->ptp.tx_interrupt_mode == ICE_PTP_TX_INTERRUPT_SELF)
> -		ice_ptp_configure_tx_tstamp(pf, on);
> +		ice_ptp_cfg_tx_interrupt(pf, on);
>  
>  	pf->ptp.tstamp_config.tx_type = on ? HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF;
>  }
> @@ -591,9 +591,11 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
>  	hw = &pf->hw;
>  
>  	/* Read the Tx ready status first */
> -	err = ice_get_phy_tx_tstamp_ready(hw, tx->block, &tstamp_ready);
> -	if (err)
> -		return;
> +	if (tx->has_ready_bitmap) {
> +		err = ice_get_phy_tx_tstamp_ready(hw, tx->block, &tstamp_ready);
> +		if (err)
> +			return;
> +	}
>  
>  	/* Drop packets if the link went down */
>  	link_up = ptp_port->link_up;
> @@ -621,7 +623,8 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
>  		 * If we do not, the hardware logic for generating a new
>  		 * interrupt can get stuck on some devices.
>  		 */
> -		if (!(tstamp_ready & BIT_ULL(phy_idx))) {
> +		if (tx->has_ready_bitmap &&
> +		    !(tstamp_ready & BIT_ULL(phy_idx))) {
>  			if (drop_ts)
>  				goto skip_ts_read;
>  
> @@ -641,7 +644,7 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
>  		 * from the last cached timestamp. If it is not, skip this for
>  		 * now assuming it hasn't yet been captured by hardware.
>  		 */
> -		if (!drop_ts && tx->verify_cached &&
> +		if (!drop_ts && !tx->has_ready_bitmap &&
>  		    raw_tstamp == tx->tstamps[idx].cached_tstamp)
>  			continue;
>  
> @@ -651,7 +654,7 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
>  
>  skip_ts_read:
>  		spin_lock(&tx->lock);
> -		if (tx->verify_cached && raw_tstamp)
> +		if (!tx->has_ready_bitmap && raw_tstamp)
>  			tx->tstamps[idx].cached_tstamp = raw_tstamp;
>  		clear_bit(idx, tx->in_use);
>  		skb = tx->tstamps[idx].skb;
> @@ -895,7 +898,7 @@ ice_ptp_init_tx_e822(struct ice_pf *pf, struct ice_ptp_tx *tx, u8 port)
>  	tx->block = port / ICE_PORTS_PER_QUAD;
>  	tx->offset = (port % ICE_PORTS_PER_QUAD) * INDEX_PER_PORT_E822;
>  	tx->len = INDEX_PER_PORT_E822;
> -	tx->verify_cached = 0;
> +	tx->has_ready_bitmap = 1;
>  
>  	return ice_ptp_alloc_tx_tracker(tx);
>  }
> @@ -918,7 +921,7 @@ ice_ptp_init_tx_e810(struct ice_pf *pf, struct ice_ptp_tx *tx)
>  	 * verify new timestamps against cached copy of the last read
>  	 * timestamp.
>  	 */
> -	tx->verify_cached = 1;
> +	tx->has_ready_bitmap = 0;
>  
>  	return ice_ptp_alloc_tx_tracker(tx);
>  }
> @@ -1338,14 +1341,14 @@ void ice_ptp_link_change(struct ice_pf *pf, u8 port, bool linkup)
>  }
>  
>  /**
> - * ice_ptp_tx_ena_intr - Enable or disable the Tx timestamp interrupt
> + * ice_ptp_cfg_phy_interrupt - Configure PHY interrupt settings

This should be in a separate patch, it looks like it got accidentally
squashed into this when rebasing.

>   * @pf: PF private structure
>   * @ena: bool value to enable or disable interrupt
>   * @threshold: Minimum number of packets at which intr is triggered
>   *
>   * Utility function to enable or disable Tx timestamp interrupt and threshold
>   */
> -static int ice_ptp_tx_ena_intr(struct ice_pf *pf, bool ena, u32 threshold)
> +static int ice_ptp_cfg_phy_interrupt(struct ice_pf *pf, bool ena, u32 threshold)
>  {
>  	struct ice_hw *hw = &pf->hw;
>  	int err = 0;
> @@ -2507,8 +2510,8 @@ void ice_ptp_reset(struct ice_pf *pf, enum ice_reset_req reset_type)
>  	struct ice_ptp *ptp = &pf->ptp;
>  	struct ice_hw *hw = &pf->hw;
>  	struct timespec64 ts;
> -	int err, itr = 1;
>  	u64 time_diff;
> +	int err;
>  
>  	if (ptp->state != ICE_PTP_RESETTING) {
>  		if (ptp->state == ICE_PTP_READY) {
> @@ -2561,7 +2564,7 @@ void ice_ptp_reset(struct ice_pf *pf, enum ice_reset_req reset_type)
>  
>  	if (!ice_is_e810(hw)) {
>  		/* Enable quad interrupts */
> -		err = ice_ptp_tx_ena_intr(pf, true, itr);
> +		err = ice_ptp_cfg_phy_interrupt(pf, true, 1);
>  		if (err)
>  			goto err;
>  	}
> @@ -2847,13 +2850,13 @@ static int ice_ptp_init_owner(struct ice_pf *pf)
>  		/* The clock owner for this device type handles the timestamp
>  		 * interrupt for all ports.
>  		 */
> -		ice_ptp_configure_tx_tstamp(pf, true);
> +		ice_ptp_cfg_tx_interrupt(pf, true);

This looks like a change that got accidentally squashed into this patch.

>  
>  		/* React on all quads interrupts for E82x */
>  		wr32(hw, PFINT_TSYN_MSK + (0x4 * hw->pf_id), (u32)0x1f);
>  
>  		/* Enable quad interrupts */
> -		err = ice_ptp_tx_ena_intr(pf, true, itr);
> +		err = ice_ptp_cfg_phy_interrupt(pf, true, itr);
>  		if (err)
>  			goto err_exit;
>  	}
> @@ -2925,7 +2928,7 @@ static int ice_ptp_init_port(struct ice_pf *pf, struct ice_ptp_port *ptp_port)
>  		 * neither on own quad nor on others
>  		 */
>  		if (!ice_ptp_pf_handles_tx_interrupt(pf)) {
> -			ice_ptp_configure_tx_tstamp(pf, false);
> +			ice_ptp_cfg_tx_interrupt(pf, false);>  			wr32(hw, PFINT_TSYN_MSK + (0x4 * hw->pf_id), (u32)0x0);
>  		}
>  		kthread_init_delayed_work(&ptp_port->ov_work,
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
> index 48c0d56c0568..30ad714a2a21 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.h
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
> @@ -100,7 +100,7 @@ struct ice_perout_channel {
>   * the last timestamp we read for a given index. If the current timestamp
>   * value is the same as the cached value, we assume a new timestamp hasn't
>   * been captured. This avoids reporting stale timestamps to the stack. This is
> - * only done if the verify_cached flag is set in ice_ptp_tx structure.
> + * only done if the has_ready_bitmap flag is not set in ice_ptp_tx structure.
>   */
>  struct ice_tx_tstamp {
>  	struct sk_buff *skb;
> @@ -131,6 +131,9 @@ enum ice_tx_tstamp_work {
>   * @calibrating: if true, the PHY is calibrating the Tx offset. During this
>   *               window, timestamps are temporarily disabled.
>   * @verify_cached: if true, verify new timestamp differs from last read value


We're using has_ready_bitmap instead, but we still kept verify_cached in
the structure. Oops.

> + * @has_ready_bitmap: if true, the hardware has a valid Tx timestamp ready
> + *                    bitmap register. If false, fall back to verifying new
> + *                    timestamp values against previously cached copy.
>   */
>  struct ice_ptp_tx {
>  	spinlock_t lock; /* lock protecting in_use bitmap */
> @@ -143,6 +146,7 @@ struct ice_ptp_tx {
>  	u8 init : 1;
>  	u8 calibrating : 1;
>  	u8 verify_cached : 1;
> +	u8 has_ready_bitmap : 1;
>  };
>  
>  /* Quad and port information for initializing timestamp blocks */

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