Re: [PATCH v2 5/7] net: dsa: b53: Add logic for RX timestamping

[Florian Fainelli]

On 11/9/21 1:50 AM, Martin Kaistra wrote:
> Packets received by the tagger with opcode=1 contain the 32-bit timestamp
> according to the timebase register. This timestamp is saved in
> BRCM_SKB_CB(skb)->meta_tstamp. b53_port_rxtstamp() takes this
> and puts the full time information from the timecounter into
> shwt->hwtstamp.
> 
> Signed-off-by: Martin Kaistra <martin.kaistra@xxxxxxxxxxxxx>
> ---
>  drivers/net/dsa/b53/b53_common.c |  1 +
>  drivers/net/dsa/b53/b53_ptp.c    | 28 +++++++++++++++++++++++++
>  drivers/net/dsa/b53/b53_ptp.h    | 10 +++++++++
>  include/linux/dsa/b53.h          | 30 +++++++++++++++++++++++++++
>  net/dsa/tag_brcm.c               | 35 ++++++++++++++++++++++++--------
>  5 files changed, 95 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> index ed590efbd3bf..a9408f9cd414 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -2300,6 +2300,7 @@ static const struct dsa_switch_ops b53_switch_ops = {
>  	.port_max_mtu		= b53_get_max_mtu,
>  	.port_change_mtu	= b53_change_mtu,
>  	.get_ts_info		= b53_get_ts_info,
> +	.port_rxtstamp		= b53_port_rxtstamp,
>  };
>  
>  struct b53_chip_data {
> diff --git a/drivers/net/dsa/b53/b53_ptp.c b/drivers/net/dsa/b53/b53_ptp.c
> index 8629c510b1a0..f8dd8d484d93 100644
> --- a/drivers/net/dsa/b53/b53_ptp.c
> +++ b/drivers/net/dsa/b53/b53_ptp.c
> @@ -6,6 +6,8 @@
>   * Copyright (C) 2021 Linutronix GmbH
>   */
>  
> +#include <linux/ptp_classify.h>
> +
>  #include "b53_priv.h"
>  #include "b53_ptp.h"
>  
> @@ -106,6 +108,32 @@ static long b53_hwtstamp_work(struct ptp_clock_info *ptp)
>  	return B53_PTP_OVERFLOW_PERIOD;
>  }
>  
> +bool b53_port_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb,
> +		       unsigned int type)
> +{
> +	struct b53_device *dev = ds->priv;
> +	struct b53_port_hwtstamp *ps = &dev->ports[port].port_hwtstamp;
> +	struct skb_shared_hwtstamps *shwt;
> +	u64 ns;

I had asked you to store b53_port_hwtstamp into dp->priv, any reason for
not doing that?

> +
> +	if (type != PTP_CLASS_V2_L2)
> +		return false;
> +
> +	if (!test_bit(B53_HWTSTAMP_ENABLED, &ps->state))
> +		return false;
> +
> +	mutex_lock(&dev->ptp_mutex);
> +	ns = timecounter_cyc2time(&dev->tc, BRCM_SKB_CB(skb)->meta_tstamp);
> +	mutex_unlock(&dev->ptp_mutex);
> +
> +	shwt = skb_hwtstamps(skb);
> +	memset(shwt, 0, sizeof(*shwt));
> +	shwt->hwtstamp = ns_to_ktime(ns);
> +
> +	return false;
> +}
> +EXPORT_SYMBOL(b53_port_rxtstamp);
> +
>  int b53_ptp_init(struct b53_device *dev)
>  {
>  	mutex_init(&dev->ptp_mutex);
> diff --git a/drivers/net/dsa/b53/b53_ptp.h b/drivers/net/dsa/b53/b53_ptp.h
> index 5cd2fd9621a2..3b3437870c55 100644
> --- a/drivers/net/dsa/b53/b53_ptp.h
> +++ b/drivers/net/dsa/b53/b53_ptp.h
> @@ -9,11 +9,15 @@
>  
>  #include "b53_priv.h"
>  
> +#define SKB_PTP_TYPE(__skb) (*(unsigned int *)((__skb)->cb))
> +
>  #ifdef CONFIG_B53_PTP
>  int b53_ptp_init(struct b53_device *dev);
>  void b53_ptp_exit(struct b53_device *dev);
>  int b53_get_ts_info(struct dsa_switch *ds, int port,
>  		    struct ethtool_ts_info *info);
> +bool b53_port_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb,
> +		       unsigned int type);
>  #else /* !CONFIG_B53_PTP */
>  
>  static inline int b53_ptp_init(struct b53_device *dev)
> @@ -31,5 +35,11 @@ static inline int b53_get_ts_info(struct dsa_switch *ds, int port,
>  	return -EOPNOTSUPP;
>  }
>  
> +static inline bool b53_port_rxtstamp(struct dsa_switch *ds, int port,
> +				     struct sk_buff *skb, unsigned int type)
> +{
> +	return false;
> +}
> +
>  #endif
>  #endif
> diff --git a/include/linux/dsa/b53.h b/include/linux/dsa/b53.h
> index 85aa6d9dc53d..542e5e3040d6 100644
> --- a/include/linux/dsa/b53.h
> +++ b/include/linux/dsa/b53.h
> @@ -46,9 +46,32 @@ struct b53_io_ops {
>  					struct phylink_link_state *state);
>  };
>  
> +/* state flags for b53_port_hwtstamp::state */
> +enum {
> +	B53_HWTSTAMP_ENABLED,
> +	B53_HWTSTAMP_TX_IN_PROGRESS,
> +};
> +
> +struct b53_port_hwtstamp {
> +	/* Port index */
> +	int port_id;

unsigned int;

> +
> +	/* Timestamping state */
> +	unsigned long state;
> +
> +	/* Resources for transmit timestamping */
> +	unsigned long tx_tstamp_start;
> +	struct sk_buff *tx_skb;
> +
> +	/* Current timestamp configuration */
> +	struct hwtstamp_config tstamp_config;
> +};
> +
>  struct b53_port {
>  	u16 vlan_ctl_mask;
>  	struct ethtool_eee eee;
> +	/* Per-port timestamping resources */
> +	struct b53_port_hwtstamp port_hwtstamp;
>  };
>  
>  struct b53_vlan {
> @@ -112,3 +135,10 @@ struct b53_device {
>  #define B53_PTP_OVERFLOW_PERIOD (HZ / 2)
>  	struct delayed_work overflow_work;
>  };
> +
> +struct brcm_skb_cb {
> +	struct sk_buff *clone;
> +	u32 meta_tstamp;
> +};
> +
> +#define BRCM_SKB_CB(skb) ((struct brcm_skb_cb *)(skb)->cb)
> diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
> index 96dbb8ee2fee..d611c1073deb 100644
> --- a/net/dsa/tag_brcm.c
> +++ b/net/dsa/tag_brcm.c
> @@ -9,6 +9,7 @@
>  #include <linux/etherdevice.h>
>  #include <linux/list.h>
>  #include <linux/slab.h>
> +#include <linux/dsa/b53.h>
>  
>  #include "dsa_priv.h"
>  
> @@ -31,7 +32,10 @@
>  /* 6th byte in the tag */
>  #define BRCM_LEG_PORT_ID	(0xf)
>  
> -/* Newer Broadcom tag (4 bytes) */
> +/* Newer Broadcom tag (4 bytes)
> + * For egress, when opcode = 0001, additional 4 bytes are used for
> + * the time stamp.
> + */
>  #define BRCM_TAG_LEN	4
>  
>  /* Tag is constructed and desconstructed using byte by byte access
> @@ -136,19 +140,29 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
>   */
>  static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
>  				       struct net_device *dev,
> -				       unsigned int offset)
> +				       unsigned int offset,
> +				       int *tag_len)

unsigned int tag_len.
-- 
Florian