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

From: Florian Fainelli
Date: Tue Nov 09 2021 - 13:07:44 EST


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