Date:   Thu, 10 Sep 2020 10:30:10 +0000
From:   Ioana Ciornei <ioana.ciornei@....com>
To:     "Y.b. Lu" <yangbo.lu@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "Y.b. Lu" <yangbo.lu@....com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Richard Cochran <richardcochran@...il.com>
Subject: RE: [v2, 5/5] dpaa2-eth: support PTP Sync packet one-step
 timestamping

> Subject: [v2, 5/5] dpaa2-eth: support PTP Sync packet one-step timestamping
> 
> This patch is to add PTP sync packet one-step timestamping support.
> Before egress, one-step timestamping enablement needs,
> 
> - Enabling timestamp and FAS (Frame Annotation Status) in
>   dpni buffer layout.
> 
> - Write timestamp to frame annotation and set PTP bit in
>   FAS to mark as one-step timestamping event.
> 
> - Enabling one-step timestamping by dpni_set_single_step_cfg()
>   API, with offset provided to insert correction time on frame.
>   The offset must respect all MAC headers, VLAN tags and other
>   protocol headers accordingly. The correction field update can
>   consider delays up to one second. So PTP frame needs to be
>   filtered and parsed, and written timestamp into Sync frame
>   originTimestamp field.
> 
> The operation of API dpni_set_single_step_cfg() has to be done when no one-
> step timestamping frames are in flight. So we have to make sure the last one-
> step timestamping frame has already been transmitted on hardware before
> starting to send the current one. The resolution is,
> 
> - Utilize skb->cb[0] to mark timestamping request per packet.
>   If it is one-step timestamping PTP sync packet, queue to skb queue.
>   If not, transmit immediately.
> 
> - Schedule a work to transmit skbs in skb queue.
> 
> - mutex lock is used to ensure the last one-step timestamping packet
>   has already been transmitted on hardware through TX confirmation queue
>   before transmitting current packet.
> 
> Signed-off-by: Yangbo Lu <yangbo.lu@....com>
> ---
> Changes for v2:
> 	- None.
> ---
>  drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c   | 206
> +++++++++++++++++++--
>  drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h   |  32 +++-
>  .../net/ethernet/freescale/dpaa2/dpaa2-ethtool.c   |   4 +-
>  3 files changed, 226 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> index eab9470..e54381c 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> @@ -15,6 +15,7 @@
>  #include <linux/bpf.h>
>  #include <linux/bpf_trace.h>
>  #include <linux/fsl/ptp_qoriq.h>
> +#include <linux/ptp_classify.h>
>  #include <net/pkt_cls.h>
>  #include <net/sock.h>
> 
> @@ -563,11 +564,72 @@ static int dpaa2_eth_consume_frames(struct
> dpaa2_eth_channel *ch,
>  	return cleaned;
>  }
> 
> +static int dpaa2_eth_ptp_parse(struct sk_buff *skb, u8 *msg_type, u8
> *two_step,
> +			       u8 *udp, u16 *correction_offset,
> +			       u16 *origin_timestamp_offset) {
> +	unsigned int ptp_class;
> +	u16 offset = 0;
> +	u8 *data;
> +
> +	data = skb_mac_header(skb);
> +	ptp_class = ptp_classify_raw(skb);
> +
> +	switch (ptp_class & PTP_CLASS_VMASK) {
> +	case PTP_CLASS_V1:
> +	case PTP_CLASS_V2:
> +		break;
> +	default:
> +		return -ERANGE;
> +	}
> +
> +	if (ptp_class & PTP_CLASS_VLAN)
> +		offset += VLAN_HLEN;
> +
> +	switch (ptp_class & PTP_CLASS_PMASK) {
> +	case PTP_CLASS_IPV4:
> +		offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
> +		*udp = 1;
> +		break;
> +	case PTP_CLASS_IPV6:
> +		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
> +		*udp = 1;
> +		break;
> +	case PTP_CLASS_L2:
> +		offset += ETH_HLEN;
> +		*udp = 0;
> +		break;
> +	default:
> +		return -ERANGE;
> +	}
> +
> +	/* PTP header is 34 bytes. */
> +	if (skb->len < offset + 34)
> +		return -EINVAL;
> +
> +	*msg_type = data[offset] & 0x0f;
> +	*two_step = data[offset + 6] & 0x2;
> +	*correction_offset = offset + 8;
> +	*origin_timestamp_offset = offset + 34;
> +	return 0;
> +}
> +

Hi Yangbo,

Kurt Kanzenbach just added a generic function, ptp_parse_header, that directly returns a struct ptp_header *.
https://patchwork.ozlabs.org/project/netdev/list/?series=196189&state=*

Maybe use this instead of open-coding it?

Thanks,
Ioana

>  /* Configure the egress frame annotation for timestamp update */ -static void
> dpaa2_eth_enable_tx_tstamp(struct dpaa2_fd *fd, void *buf_start)
> +static void dpaa2_eth_enable_tx_tstamp(struct dpaa2_eth_priv *priv,
> +				       struct dpaa2_fd *fd,
> +				       void *buf_start,
> +				       struct sk_buff *skb)
>  {
> +	struct ptp_tstamp origin_timestamp;
> +	struct dpni_single_step_cfg cfg;
> +	u8 msg_type, two_step, udp;
>  	struct dpaa2_faead *faead;
> +	struct dpaa2_fas *fas;
> +	struct timespec64 ts;
> +	u16 offset1, offset2;
>  	u32 ctrl, frc;
> +	__le64 *ns;
> +	u8 *data;
> 
>  	/* Mark the egress frame annotation area as valid */
>  	frc = dpaa2_fd_get_frc(fd);
> @@ -583,6 +645,58 @@ static void dpaa2_eth_enable_tx_tstamp(struct
> dpaa2_fd *fd, void *buf_start)
>  	ctrl = DPAA2_FAEAD_A2V | DPAA2_FAEAD_UPDV | DPAA2_FAEAD_UPD;
>  	faead = dpaa2_get_faead(buf_start, true);
>  	faead->ctrl = cpu_to_le32(ctrl);
> +
> +	if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> +		if (dpaa2_eth_ptp_parse(skb, &msg_type, &two_step, &udp,
> +					&offset1, &offset2)) {
> +			netdev_err(priv->net_dev,
> +				   "bad packet for one-step timestamping\n");
> +			return;
> +		}
> +
> +		if (msg_type != 0 || two_step) {
> +			netdev_err(priv->net_dev,
> +				   "bad packet for one-step timestamping\n");
> +			return;
> +		}
> +
> +		/* Mark the frame annotation status as valid */
> +		frc = dpaa2_fd_get_frc(fd);
> +		dpaa2_fd_set_frc(fd, frc | DPAA2_FD_FRC_FASV);
> +
> +		/* Mark the PTP flag for one step timestamping */
> +		fas = dpaa2_get_fas(buf_start, true);
> +		fas->status = cpu_to_le32(DPAA2_FAS_PTP);
> +
> +		/* Write current time to FA timestamp field */
> +		if (!dpaa2_ptp) {
> +			netdev_err(priv->net_dev,
> +				   "ptp driver may not loaded for one-step
> timestamping\n");
> +			return;
> +		}
> +		dpaa2_ptp->caps.gettime64(&dpaa2_ptp->caps, &ts);
> +		ns = dpaa2_get_ts(buf_start, true);
> +		*ns = cpu_to_le64(timespec64_to_ns(&ts) /
> +				  DPAA2_PTP_CLK_PERIOD_NS);
> +
> +		/* Update current time to PTP message originTimestamp field
> */
> +		ns_to_ptp_tstamp(&origin_timestamp, le64_to_cpup(ns));
> +		data = skb_mac_header(skb);
> +		*(__be16 *)(data + offset2) =
> htons(origin_timestamp.sec_msb);
> +		*(__be32 *)(data + offset2 + 2) =
> +			htonl(origin_timestamp.sec_lsb);
> +		*(__be32 *)(data + offset2 + 6) = htonl(origin_timestamp.nsec);
> +
> +		cfg.en = 1;
> +		cfg.ch_update = udp;
> +		cfg.offset = offset1;
> +		cfg.peer_delay = 0;
> +
> +		if (dpni_set_single_step_cfg(priv->mc_io, 0, priv->mc_token,
> +					     &cfg))
> +			netdev_err(priv->net_dev,
> +				   "dpni_set_single_step_cfg failed\n");
> +	}
>  }
> 
>  /* Create a frame descriptor based on a fragmented skb */ @@ -820,7 +934,7
> @@ static int dpaa2_eth_build_single_fd(struct dpaa2_eth_priv *priv,
>   * This can be called either from dpaa2_eth_tx_conf() or on the error path of
>   * dpaa2_eth_tx().
>   */
> -static void dpaa2_eth_free_tx_fd(const struct dpaa2_eth_priv *priv,
> +static void dpaa2_eth_free_tx_fd(struct dpaa2_eth_priv *priv,
>  				 struct dpaa2_eth_fq *fq,
>  				 const struct dpaa2_fd *fd, bool in_napi)  { @@
> -903,6 +1017,8 @@ static void dpaa2_eth_free_tx_fd(const struct
> dpaa2_eth_priv *priv,
>  		ns = DPAA2_PTP_CLK_PERIOD_NS * le64_to_cpup(ts);
>  		shhwtstamps.hwtstamp = ns_to_ktime(ns);
>  		skb_tstamp_tx(skb, &shhwtstamps);
> +	} else if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> +		mutex_unlock(&priv->onestep_tstamp_lock);
>  	}
> 
>  	/* Free SGT buffer allocated on tx */
> @@ -922,7 +1038,8 @@ static void dpaa2_eth_free_tx_fd(const struct
> dpaa2_eth_priv *priv,
>  	napi_consume_skb(skb, in_napi);
>  }
> 
> -static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb, struct net_device
> *net_dev)
> +static netdev_tx_t __dpaa2_eth_tx(struct sk_buff *skb,
> +				  struct net_device *net_dev)
>  {
>  	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
>  	struct dpaa2_fd fd;
> @@ -937,13 +1054,6 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb,
> struct net_device *net_dev)
>  	int err, i;
>  	void *swa;
> 
> -	/* Utilize skb->cb[0] for timestamping request per skb */
> -	skb->cb[0] = 0;
> -
> -	if (priv->tx_tstamp_type == HWTSTAMP_TX_ON &&
> -	    skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
> -		skb->cb[0] = TX_TSTAMP;
> -
>  	percpu_stats = this_cpu_ptr(priv->percpu_stats);
>  	percpu_extras = this_cpu_ptr(priv->percpu_extras);
> 
> @@ -981,8 +1091,8 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb,
> struct net_device *net_dev)
>  		goto err_build_fd;
>  	}
> 
> -	if (skb->cb[0] == TX_TSTAMP)
> -		dpaa2_eth_enable_tx_tstamp(&fd, swa);
> +	if (skb->cb[0])
> +		dpaa2_eth_enable_tx_tstamp(priv, &fd, swa, skb);
> 
>  	/* Tracing point */
>  	trace_dpaa2_tx_fd(net_dev, &fd);
> @@ -1037,6 +1147,58 @@ static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb,
> struct net_device *net_dev)
>  	return NETDEV_TX_OK;
>  }
> 
> +static void dpaa2_eth_tx_onestep_tstamp(struct work_struct *work) {
> +	struct dpaa2_eth_priv *priv = container_of(work, struct dpaa2_eth_priv,
> +						   tx_onestep_tstamp);
> +	struct sk_buff *skb;
> +
> +	while (true) {
> +		skb = skb_dequeue(&priv->tx_skbs);
> +		if (!skb)
> +			return;
> +
> +		mutex_lock(&priv->onestep_tstamp_lock);
> +		__dpaa2_eth_tx(skb, priv->net_dev);
> +	}
> +}
> +
> +static netdev_tx_t dpaa2_eth_tx(struct sk_buff *skb, struct net_device
> +*net_dev) {
> +	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
> +	u8 msg_type, two_step, udp;
> +	u16 offset1, offset2;
> +
> +	/* Utilize skb->cb[0] for timestamping request per skb */
> +	skb->cb[0] = 0;
> +
> +	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
> +		if (priv->tx_tstamp_type == HWTSTAMP_TX_ON)
> +			skb->cb[0] = TX_TSTAMP;
> +		else if (priv->tx_tstamp_type ==
> HWTSTAMP_TX_ONESTEP_SYNC)
> +			skb->cb[0] = TX_TSTAMP_ONESTEP_SYNC;
> +	}
> +
> +	/* TX for one-step timestamping PTP Sync packet */
> +	if (skb->cb[0] == TX_TSTAMP_ONESTEP_SYNC) {
> +		if (!dpaa2_eth_ptp_parse(skb, &msg_type, &two_step, &udp,
> +					 &offset1, &offset2))
> +			if (msg_type == 0 && two_step == 0) {
> +				skb_queue_tail(&priv->tx_skbs, skb);
> +				queue_work(priv->dpaa2_ptp_wq,
> +					   &priv->tx_onestep_tstamp);
> +				return NETDEV_TX_OK;
> +			}
> +		/* Use two-step timestamping if not one-step timestamping
> +		 * PTP Sync packet
> +		 */
> +		skb->cb[0] = TX_TSTAMP;
> +	}
> +
> +	/* TX for other packets */
> +	return __dpaa2_eth_tx(skb, net_dev);
> +}
> +
>  /* Tx confirmation frame processing routine */  static void
> dpaa2_eth_tx_conf(struct dpaa2_eth_priv *priv,
>  			      struct dpaa2_eth_channel *ch __always_unused,
> @@ -1906,6 +2068,7 @@ static int dpaa2_eth_ts_ioctl(struct net_device *dev,
> struct ifreq *rq, int cmd)
>  	switch (config.tx_type) {
>  	case HWTSTAMP_TX_OFF:
>  	case HWTSTAMP_TX_ON:
> +	case HWTSTAMP_TX_ONESTEP_SYNC:
>  		priv->tx_tstamp_type = config.tx_type;
>  		break;
>  	default:
> @@ -2731,8 +2894,10 @@ static int dpaa2_eth_set_buffer_layout(struct
> dpaa2_eth_priv *priv)
>  	/* tx buffer */
>  	buf_layout.private_data_size = DPAA2_ETH_SWA_SIZE;
>  	buf_layout.pass_timestamp = true;
> +	buf_layout.pass_frame_status = true;
>  	buf_layout.options = DPNI_BUF_LAYOUT_OPT_PRIVATE_DATA_SIZE |
> -			     DPNI_BUF_LAYOUT_OPT_TIMESTAMP;
> +			     DPNI_BUF_LAYOUT_OPT_TIMESTAMP |
> +			     DPNI_BUF_LAYOUT_OPT_FRAME_STATUS;
>  	err = dpni_set_buffer_layout(priv->mc_io, 0, priv->mc_token,
>  				     DPNI_QUEUE_TX, &buf_layout);
>  	if (err) {
> @@ -2741,7 +2906,8 @@ static int dpaa2_eth_set_buffer_layout(struct
> dpaa2_eth_priv *priv)
>  	}
> 
>  	/* tx-confirm buffer */
> -	buf_layout.options = DPNI_BUF_LAYOUT_OPT_TIMESTAMP;
> +	buf_layout.options = DPNI_BUF_LAYOUT_OPT_TIMESTAMP |
> +			     DPNI_BUF_LAYOUT_OPT_FRAME_STATUS;
>  	err = dpni_set_buffer_layout(priv->mc_io, 0, priv->mc_token,
>  				     DPNI_QUEUE_TX_CONFIRM, &buf_layout);
>  	if (err) {
> @@ -3969,6 +4135,16 @@ static int dpaa2_eth_probe(struct fsl_mc_device
> *dpni_dev)
>  	priv->tx_tstamp_type = HWTSTAMP_TX_OFF;
>  	priv->rx_tstamp = false;
> 
> +	priv->dpaa2_ptp_wq = alloc_workqueue("dpaa2_ptp_wq", 0, 0);
> +	if (!priv->dpaa2_ptp_wq) {
> +		err = -ENOMEM;
> +		goto err_wq_alloc;
> +	}
> +
> +	INIT_WORK(&priv->tx_onestep_tstamp,
> dpaa2_eth_tx_onestep_tstamp);
> +
> +	skb_queue_head_init(&priv->tx_skbs);
> +
>  	/* Obtain a MC portal */
>  	err = fsl_mc_portal_allocate(dpni_dev,
> FSL_MC_IO_ATOMIC_CONTEXT_PORTAL,
>  				     &priv->mc_io);
> @@ -4107,6 +4283,8 @@ static int dpaa2_eth_probe(struct fsl_mc_device
> *dpni_dev)
>  err_dpni_setup:
>  	fsl_mc_portal_free(priv->mc_io);
>  err_portal_alloc:
> +	destroy_workqueue(priv->dpaa2_ptp_wq);
> +err_wq_alloc:
>  	dev_set_drvdata(dev, NULL);
>  	free_netdev(net_dev);
> 
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> index 57e6e6e..c5a8e38 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
> @@ -195,6 +195,24 @@ struct dpaa2_faead {
>  #define DPAA2_FAEAD_EBDDV		0x00002000
>  #define DPAA2_FAEAD_UPD			0x00000010
> 
> +struct ptp_tstamp {
> +	u16 sec_msb;
> +	u32 sec_lsb;
> +	u32 nsec;
> +};
> +
> +static inline void ns_to_ptp_tstamp(struct ptp_tstamp *tstamp, u64 ns)
> +{
> +	u64 sec, nsec;
> +
> +	sec = ns / 1000000000ULL;
> +	nsec = ns % 1000000000ULL;
> +
> +	tstamp->sec_lsb = sec & 0xFFFFFFFF;
> +	tstamp->sec_msb = (sec >> 32) & 0xFFFF;
> +	tstamp->nsec = nsec;
> +}
> +
>  /* Accessors for the hardware annotation fields that we use */  static inline void
> *dpaa2_get_hwa(void *buf_addr, bool swa)  { @@ -474,9 +492,21 @@ struct
> dpaa2_eth_priv {  #endif
> 
>  	struct dpaa2_mac *mac;
> +	struct workqueue_struct	*dpaa2_ptp_wq;
> +	struct work_struct	tx_onestep_tstamp;
> +	struct sk_buff_head	tx_skbs;
> +	/* The one-step timestamping configuration on hardware
> +	 * registers could only be done when no one-step
> +	 * timestamping frames are in flight. So we use a mutex
> +	 * lock here to make sure the lock is released by last
> +	 * one-step timestamping packet through TX confirmation
> +	 * queue before transmit current packet.
> +	 */
> +	struct mutex		onestep_tstamp_lock;
>  };
> 
>  #define TX_TSTAMP		0x1
> +#define TX_TSTAMP_ONESTEP_SYNC	0x2
> 
>  #define DPAA2_RXH_SUPPORTED	(RXH_L2DA | RXH_VLAN |
> RXH_L3_PROTO \
>  				| RXH_IP_SRC | RXH_IP_DST | RXH_L4_B_0_1 \
> @@ -580,7 +610,7 @@ static inline unsigned int
> dpaa2_eth_needed_headroom(struct sk_buff *skb)
>  		return 0;
> 
>  	/* If we have Tx timestamping, need 128B hardware annotation */
> -	if (skb->cb[0] == TX_TSTAMP)
> +	if (skb->cb[0])
>  		headroom += DPAA2_ETH_TX_HWA_SIZE;
> 
>  	return headroom;
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> index 26bd99b..bf3baf6 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
>  /* Copyright 2014-2016 Freescale Semiconductor Inc.
>   * Copyright 2016 NXP
> + * Copyright 2020 NXP
>   */
> 
>  #include <linux/net_tstamp.h>
> @@ -770,7 +771,8 @@ static int dpaa2_eth_get_ts_info(struct net_device
> *dev,
>  	info->phc_index = dpaa2_phc_index;
> 
>  	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
> -			 (1 << HWTSTAMP_TX_ON);
> +			 (1 << HWTSTAMP_TX_ON) |
> +			 (1 << HWTSTAMP_TX_ONESTEP_SYNC);
> 
>  	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
>  			   (1 << HWTSTAMP_FILTER_ALL);
> --
> 2.7.4

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