Messages in this thread Patch in this message | | | From | Martin Kaistra <> | Subject | [PATCH 6/7] net: dsa: b53: Add logic for TX timestamping | Date | Thu, 4 Nov 2021 14:32:00 +0100 |
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In order to get the switch to generate a timestamp for a transmitted packet, we need to set the TS bit in the BRCM tag. The switch will then create a status frame, which gets send back to the cpu. In b53_port_txtstamp() we put the skb into a waiting position.
When a status frame is received, we extract the timestamp and put the time according to our timecounter into the waiting skb. When TX_TSTAMP_TIMEOUT is reached and we have no means to correctly get back a full timestamp, we cancel the process.
As the status frame doesn't contain a reference to the original packet, only one packet with timestamp request can be sent at a time.
Signed-off-by: Martin Kaistra <martin.kaistra@linutronix.de> --- drivers/net/dsa/b53/b53_common.c | 1 + drivers/net/dsa/b53/b53_ptp.c | 59 ++++++++++++++++++++++++++++++++ drivers/net/dsa/b53/b53_ptp.h | 9 +++++ net/dsa/tag_brcm.c | 51 +++++++++++++++++++++++++++ 4 files changed, 120 insertions(+)
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c index a9408f9cd414..56a9de89b38b 100644 --- a/drivers/net/dsa/b53/b53_common.c +++ b/drivers/net/dsa/b53/b53_common.c @@ -2301,6 +2301,7 @@ static const struct dsa_switch_ops b53_switch_ops = { .port_change_mtu = b53_change_mtu, .get_ts_info = b53_get_ts_info, .port_rxtstamp = b53_port_rxtstamp, + .port_txtstamp = b53_port_txtstamp, }; struct b53_chip_data { diff --git a/drivers/net/dsa/b53/b53_ptp.c b/drivers/net/dsa/b53/b53_ptp.c index 86ebaa522084..7cb4d1c9d6f7 100644 --- a/drivers/net/dsa/b53/b53_ptp.c +++ b/drivers/net/dsa/b53/b53_ptp.c @@ -109,6 +109,64 @@ static void b53_ptp_overflow_check(struct work_struct *work) schedule_delayed_work(&dev->overflow_work, B53_PTP_OVERFLOW_PERIOD); } +static long b53_hwtstamp_work(struct ptp_clock_info *ptp) +{ + struct b53_device *dev = + container_of(ptp, struct b53_device, ptp_clock_info); + struct dsa_switch *ds = dev->ds; + int i; + + for (i = 0; i < ds->num_ports; i++) { + struct b53_port_hwtstamp *ps; + + if (!dsa_is_user_port(ds, i)) + continue; + + ps = &dev->ports[i].port_hwtstamp; + + if (test_bit(B53_HWTSTAMP_TX_IN_PROGRESS, &ps->state) && + time_is_before_jiffies(ps->tx_tstamp_start + + TX_TSTAMP_TIMEOUT)) { + dev_err(dev->dev, + "Timeout while waiting for Tx timestamp!\n"); + dev_kfree_skb_any(ps->tx_skb); + ps->tx_skb = NULL; + clear_bit_unlock(B53_HWTSTAMP_TX_IN_PROGRESS, + &ps->state); + } + } + + return -1; +} + +void b53_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb) +{ + struct b53_device *dev = ds->priv; + struct b53_port_hwtstamp *ps = &dev->ports[port].port_hwtstamp; + struct sk_buff *clone; + unsigned int type; + + type = ptp_classify_raw(skb); + + if (type != PTP_CLASS_V2_L2) + return; + + if (!test_bit(B53_HWTSTAMP_ENABLED, &ps->state)) + return; + + clone = skb_clone_sk(skb); + if (!clone) + return; + + if (test_and_set_bit_lock(B53_HWTSTAMP_TX_IN_PROGRESS, &ps->state)) { + kfree_skb(clone); + return; + } + + ps->tx_skb = clone; + ps->tx_tstamp_start = jiffies; +} + bool b53_port_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb, unsigned int type) { @@ -172,6 +230,7 @@ int b53_ptp_init(struct b53_device *dev) dev->ptp_clock_info.gettime64 = b53_ptp_gettime; dev->ptp_clock_info.settime64 = b53_ptp_settime; dev->ptp_clock_info.enable = b53_ptp_enable; + dev->ptp_clock_info.do_aux_work = b53_hwtstamp_work; dev->ptp_clock = ptp_clock_register(&dev->ptp_clock_info, dev->dev); if (IS_ERR(dev->ptp_clock)) diff --git a/drivers/net/dsa/b53/b53_ptp.h b/drivers/net/dsa/b53/b53_ptp.h index 3b3437870c55..c76e3f4018d0 100644 --- a/drivers/net/dsa/b53/b53_ptp.h +++ b/drivers/net/dsa/b53/b53_ptp.h @@ -10,6 +10,7 @@ #include "b53_priv.h" #define SKB_PTP_TYPE(__skb) (*(unsigned int *)((__skb)->cb)) +#define TX_TSTAMP_TIMEOUT msecs_to_jiffies(40) #ifdef CONFIG_B53_PTP int b53_ptp_init(struct b53_device *dev); @@ -18,6 +19,8 @@ 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); +void b53_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb); + #else /* !CONFIG_B53_PTP */ static inline int b53_ptp_init(struct b53_device *dev) @@ -41,5 +44,11 @@ static inline bool b53_port_rxtstamp(struct dsa_switch *ds, int port, return false; } +static inline bool b53_port_txtstamp(struct dsa_switch *ds, int port, + struct sk_buff *skb) +{ + return false; +} + #endif #endif diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c index 85dc47c22008..53cd0345df1b 100644 --- a/net/dsa/tag_brcm.c +++ b/net/dsa/tag_brcm.c @@ -8,6 +8,7 @@ #include <linux/dsa/brcm.h> #include <linux/etherdevice.h> #include <linux/list.h> +#include <linux/ptp_classify.h> #include <linux/slab.h> #include <linux/dsa/b53.h> @@ -85,9 +86,14 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, unsigned int offset) { struct dsa_port *dp = dsa_slave_to_port(dev); + struct b53_device *b53_dev = dp->ds->priv; + unsigned int type = ptp_classify_raw(skb); u16 queue = skb_get_queue_mapping(skb); + struct b53_port_hwtstamp *ps; u8 *brcm_tag; + ps = &b53_dev->ports[dp->index].port_hwtstamp; + /* The Ethernet switch we are interfaced with needs packets to be at * least 64 bytes (including FCS) otherwise they will be discarded when * they enter the switch port logic. When Broadcom tags are enabled, we @@ -112,7 +118,13 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, */ brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) | ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT); + brcm_tag[1] = 0; + + if (type == PTP_CLASS_V2_L2 && + test_bit(B53_HWTSTAMP_TX_IN_PROGRESS, &ps->state)) + brcm_tag[1] = 1 << BRCM_IG_TS_SHIFT; + brcm_tag[2] = 0; if (dp->index == 8) brcm_tag[2] = BRCM_IG_DSTMAP2_MASK; @@ -126,6 +138,32 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, return skb; } +static int set_txtstamp(struct b53_device *dev, + struct b53_port_hwtstamp *ps, + int port, + u64 ns) +{ + struct skb_shared_hwtstamps shhwtstamps; + struct sk_buff *tmp_skb; + + if (!ps->tx_skb) + return 0; + + mutex_lock(&dev->ptp_mutex); + ns = timecounter_cyc2time(&dev->tc, ns); + mutex_unlock(&dev->ptp_mutex); + + memset(&shhwtstamps, 0, sizeof(shhwtstamps)); + shhwtstamps.hwtstamp = ns_to_ktime(ns); + tmp_skb = ps->tx_skb; + ps->tx_skb = NULL; + + clear_bit_unlock(B53_HWTSTAMP_TX_IN_PROGRESS, &ps->state); + skb_complete_tx_timestamp(tmp_skb, &shhwtstamps); + + return 0; +} + /* Frames with this tag have one of these two layouts: * ----------------------------------- * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM @@ -143,6 +181,9 @@ static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb, unsigned int offset, int *tag_len) { + struct b53_port_hwtstamp *ps; + struct b53_device *b53_dev; + struct dsa_port *dp; int source_port; u8 *brcm_tag; u32 tstamp; @@ -174,6 +215,16 @@ static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb, if (!skb->dev) return NULL; + /* Check whether this is a status frame */ + if (*tag_len == 8 && brcm_tag[3] & 0x20) { + dp = dsa_slave_to_port(skb->dev); + b53_dev = dp->ds->priv; + ps = &b53_dev->ports[source_port].port_hwtstamp; + + set_txtstamp(b53_dev, ps, source_port, tstamp); + return NULL; + } + /* Remove Broadcom tag and update checksum */ skb_pull_rcsum(skb, *tag_len); -- 2.20.1
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