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Date: Tue, 22 Mar 2022 22:07:21 +0100
From: Gerhard Engleder <gerhard@...leder-embedded.com>
To: richardcochran@...il.com, yangbo.lu@....com, davem@...emloft.net,
kuba@...nel.org
Cc: mlichvar@...hat.com, vinicius.gomes@...el.com,
netdev@...r.kernel.org,
Gerhard Engleder <gerhard@...leder-embedded.com>
Subject: [PATCH net-next v1 5/6] ptp: Support late timestamp determination
If a physical clock supports a free running time called cycles, then
timestamps shall be based on this time too. For TX it is known in
advance before the transmission if a timestamp based on cycles is
needed. For RX it is impossible to know which timestamp is needed before
the packet is received and assigned to a socket.
Support late timestamp determination by a physical clock. Therefore, an
address/cookie is stored within the new phc_data field of struct
skb_shared_hwtstamps. This address/cookie is provided to a new physical
clock method called gettstamp(), which returns a timestamp based on the
normal/adjustable time or based on cycles.
The previously introduced flag SKBTX_HW_TSTAMP_USE_CYCLES is reused with
an additional alias to request the late timestamp determination by the
physical clock. That is possible, because SKBTX_HW_TSTAMP_USE_CYCLES is
not used in the receive path.
Signed-off-by: Gerhard Engleder <gerhard@...leder-embedded.com>
---
drivers/ptp/ptp_clock.c | 27 ++++++++++++++++++++++++
include/linux/ptp_clock_kernel.h | 30 +++++++++++++++++++++++++++
include/linux/skbuff.h | 8 +++++++-
net/socket.c | 35 ++++++++++++++++++++++----------
4 files changed, 88 insertions(+), 12 deletions(-)
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 54b9f54ac0b2..b7a8cf27c349 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -450,6 +450,33 @@ void ptp_cancel_worker_sync(struct ptp_clock *ptp)
}
EXPORT_SYMBOL(ptp_cancel_worker_sync);
+ktime_t ptp_get_timestamp(int index,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles)
+{
+ char name[PTP_CLOCK_NAME_LEN] = "";
+ struct ptp_clock *ptp;
+ struct device *dev;
+ ktime_t ts;
+
+ snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", index);
+ dev = class_find_device_by_name(ptp_class, name);
+ if (!dev)
+ return 0;
+
+ ptp = dev_get_drvdata(dev);
+
+ if (ptp->info->gettstamp)
+ ts = ptp->info->gettstamp(ptp->info, hwtstamps, cycles);
+ else
+ ts = hwtstamps->hwtstamp;
+
+ put_device(dev);
+
+ return ts;
+}
+EXPORT_SYMBOL(ptp_get_timestamp);
+
/* module operations */
static void __exit ptp_exit(void)
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index cc6a7b2e267d..f4f0d8a880c6 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -133,6 +133,16 @@ struct ptp_system_timestamp {
* parameter cts: Contains timestamp (device,system) pair,
* where system time is realtime and monotonic.
*
+ * @gettstamp: Get hardware timestamp based on normal/adjustable time or free
+ * running time. If @getcycles64 or @getcyclesx64 are supported,
+ * then this method is required to provide timestamps based on the
+ * free running time. This method will be called if
+ * SKBTX_HW_TSTAMP_PHC is set by the driver.
+ * parameter hwtstamps: skb_shared_hwtstamps structure pointer.
+ * parameter cycles: If false, then hardware timestamp based on
+ * normal/adjustable time is requested. If true, then hardware
+ * timestamp based on free running time is requested.
+ *
* @enable: Request driver to enable or disable an ancillary feature.
* parameter request: Desired resource to enable or disable.
* parameter on: Caller passes one to enable or zero to disable.
@@ -185,6 +195,9 @@ struct ptp_clock_info {
struct ptp_system_timestamp *sts);
int (*getcrosscycles)(struct ptp_clock_info *ptp,
struct system_device_crosststamp *cts);
+ ktime_t (*gettstamp)(struct ptp_clock_info *ptp,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles);
int (*enable)(struct ptp_clock_info *ptp,
struct ptp_clock_request *request, int on);
int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
@@ -364,6 +377,19 @@ static inline void ptp_cancel_worker_sync(struct ptp_clock *ptp)
* a loadable module.
*/
+/**
+ * ptp_get_timestamp() - get timestamp of ptp clock
+ *
+ * @index: phc index of ptp pclock.
+ * @hwtstamps: skb_shared_hwtstamps structure pointer.
+ * @cycles: true for timestamp based on cycles.
+ *
+ * Returns timestamp, or 0 on error.
+ */
+ktime_t ptp_get_timestamp(int index,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles);
+
/**
* ptp_get_vclocks_index() - get all vclocks index on pclock, and
* caller is responsible to free memory
@@ -386,6 +412,10 @@ int ptp_get_vclocks_index(int pclock_index, int **vclock_index);
*/
ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index);
#else
+static inline ktime_t ptp_get_timestamp(int index,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles);
+{ return 0; }
static inline int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
{ return 0; }
static inline ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp,
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f494ddbfc826..38929c113953 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -564,7 +564,10 @@ static inline bool skb_frag_must_loop(struct page *p)
* &skb_shared_info. Use skb_hwtstamps() to get a pointer.
*/
struct skb_shared_hwtstamps {
- ktime_t hwtstamp;
+ union {
+ ktime_t hwtstamp;
+ void *phc_data;
+ };
};
/* Definitions for tx_flags in struct skb_shared_info */
@@ -581,6 +584,9 @@ enum {
/* generate hardware time stamp based on cycles if supported */
SKBTX_HW_TSTAMP_USE_CYCLES = 1 << 3,
+ /* call PHC to get actual hardware time stamp */
+ SKBTX_HW_TSTAMP_PHC = 1 << 3,
+
/* generate wifi status information (where possible) */
SKBTX_WIFI_STATUS = 1 << 4,
diff --git a/net/socket.c b/net/socket.c
index 2e932c058002..fe765d559086 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -804,21 +804,17 @@ static bool skb_is_swtx_tstamp(const struct sk_buff *skb, int false_tstamp)
return skb->tstamp && !false_tstamp && skb_is_err_queue(skb);
}
-static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb)
+static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb,
+ int if_index)
{
struct scm_ts_pktinfo ts_pktinfo;
- struct net_device *orig_dev;
if (!skb_mac_header_was_set(skb))
return;
memset(&ts_pktinfo, 0, sizeof(ts_pktinfo));
- rcu_read_lock();
- orig_dev = dev_get_by_napi_id(skb_napi_id(skb));
- if (orig_dev)
- ts_pktinfo.if_index = orig_dev->ifindex;
- rcu_read_unlock();
+ ts_pktinfo.if_index = if_index;
ts_pktinfo.pkt_length = skb->len - skb_mac_offset(skb);
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_PKTINFO,
@@ -838,6 +834,9 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
int empty = 1, false_tstamp = 0;
struct skb_shared_hwtstamps *shhwtstamps =
skb_hwtstamps(skb);
+ struct net_device *orig_dev;
+ int if_index = 0;
+ int phc_index = -1;
ktime_t hwtstamp;
/* Race occurred between timestamp enabling and packet
@@ -886,18 +885,32 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
if (shhwtstamps &&
(sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
!skb_is_swtx_tstamp(skb, false_tstamp)) {
- if (sk->sk_tsflags & SOF_TIMESTAMPING_BIND_PHC)
- hwtstamp = ptp_convert_timestamp(&shhwtstamps->hwtstamp,
- sk->sk_bind_phc);
+ rcu_read_lock();
+ orig_dev = dev_get_by_napi_id(skb_napi_id(skb));
+ if (orig_dev) {
+ if_index = orig_dev->ifindex;
+ if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP_PHC)
+ phc_index = ethtool_get_phc(orig_dev);
+ }
+ rcu_read_unlock();
+
+ if ((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP_PHC) &&
+ (phc_index != -1))
+ hwtstamp = ptp_get_timestamp(phc_index, shhwtstamps,
+ sk->sk_tsflags & SOF_TIMESTAMPING_BIND_PHC);
else
hwtstamp = shhwtstamps->hwtstamp;
+ if (sk->sk_tsflags & SOF_TIMESTAMPING_BIND_PHC)
+ hwtstamp = ptp_convert_timestamp(&hwtstamp,
+ sk->sk_bind_phc);
+
if (ktime_to_timespec64_cond(hwtstamp, tss.ts + 2)) {
empty = 0;
if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO) &&
!skb_is_err_queue(skb))
- put_ts_pktinfo(msg, skb);
+ put_ts_pktinfo(msg, skb, if_index);
}
}
if (!empty) {
--
2.20.1
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