The CPSW offers two mechanisms for communicating packet ingress timestamp
information to the host.
The first mechanism is via the CPTS Event FIFO which records timestamp
when triggered by certain events. One such event is the reception of an
Ethernet packet with a specified EtherType field. This is used to capture
ingress timestamps for PTP packets. With this mechanism the host must
read the timestamp (from the CPTS FIFO) separately from the packet payload
which is delivered via DMA.
In the second mechanism of timestamping, CPSW driver enables hardware
timestamping for all received packets by setting the TSTAMP_EN bit in
CPTS_CONTROL register, which directs the CPTS module to timestamp all
received packets, followed by passing timestamp via DMA descriptors.
This mechanism is responsible for triggering errata i2401:
"CPSW: Host Timestamps Cause CPSW Port to Lock up."
The errata affects all K3 SoCs. Link to errata for AM64x:
https://www.ti.com/lit/er/sprz457h/sprz457h.pdf
As a workaround we can use first mechanism to timestamp received
packets.
Series is based on linux-next tagged next-20240417.
Link to v5:
https://lore.kernel.org/r/[email protected]/
Changes from v5 to v6:
- Defined lockless variant of "am65_cpts_fifo_read()" as
"__am65_cpts_fifo_read()", suggested by Paolo to avoid acquiring the
same lock on cpts again in "am65_cpts_fifo_read()".
- Replaced "list_del_entry()" and "list_add()" functions with equivalent
"list_move()" function.
- Replaced "list_del_init()" and "list_add_tail()" functions with
equivalent "list_move_tail()" function.
This changes are done as per the discussion at here:
https://lore.kernel.org/r/[email protected]/
Chintan Vankar (2):
net: ethernet: ti: am65-cpts: Enable RX HW timestamp for PTP packets
using CPTS FIFO
net: ethernet: ti: am65-cpsw/ethtool: Enable RX HW timestamp only for
PTP packets
drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 13 ++-
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 51 +++++-----
drivers/net/ethernet/ti/am65-cpts.c | 107 ++++++++++++++------
drivers/net/ethernet/ti/am65-cpts.h | 11 +-
4 files changed, 118 insertions(+), 64 deletions(-)
--
2.34.1
Add a new function "am65_cpts_rx_timestamp()" which checks for PTP
packets from header and timestamps them.
Add another function "am65_cpts_find_rx_ts()" which finds CPTS FIFO
Event to get the timestamp of received PTP packet.
Signed-off-by: Chintan Vankar <[email protected]>
---
Link to v5:
https://lore.kernel.org/r/[email protected]/
Changes from v5 to v6:
- Defined lockless variant of "am65_cpts_fifo_read()" as
"__am65_cpts_fifo_read()", suggested by Paolo to avoid acquiring the
same lock on cpts again in "am65_cpts_fifo_read()".
- Replaced "list_del_entry()" and "list_add()" functions with equivalent
"list_move()" function.
- Replaced "list_del_init()" and "list_add_tail()" functions with
equivalent "list_move_tail()" function.
drivers/net/ethernet/ti/am65-cpts.c | 84 ++++++++++++++++++++++++++---
drivers/net/ethernet/ti/am65-cpts.h | 6 +++
2 files changed, 83 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/ti/am65-cpts.c b/drivers/net/ethernet/ti/am65-cpts.c
index c66618d91c28..599454c1d19f 100644
--- a/drivers/net/ethernet/ti/am65-cpts.c
+++ b/drivers/net/ethernet/ti/am65-cpts.c
@@ -275,15 +275,13 @@ static bool am65_cpts_fifo_pop_event(struct am65_cpts *cpts,
return true;
}
-static int am65_cpts_fifo_read(struct am65_cpts *cpts)
+static int __am65_cpts_fifo_read(struct am65_cpts *cpts)
{
struct ptp_clock_event pevent;
struct am65_cpts_event *event;
bool schedule = false;
int i, type, ret = 0;
- unsigned long flags;
- spin_lock_irqsave(&cpts->lock, flags);
for (i = 0; i < AM65_CPTS_FIFO_DEPTH; i++) {
event = list_first_entry_or_null(&cpts->pool,
struct am65_cpts_event, list);
@@ -312,8 +310,7 @@ static int am65_cpts_fifo_read(struct am65_cpts *cpts)
event->tmo = jiffies +
msecs_to_jiffies(AM65_CPTS_EVENT_RX_TX_TIMEOUT);
- list_del_init(&event->list);
- list_add_tail(&event->list, &cpts->events);
+ list_move_tail(&event->list, &cpts->events);
dev_dbg(cpts->dev,
"AM65_CPTS_EV_TX e1:%08x e2:%08x t:%lld\n",
@@ -356,14 +353,24 @@ static int am65_cpts_fifo_read(struct am65_cpts *cpts)
}
out:
- spin_unlock_irqrestore(&cpts->lock, flags);
-
if (schedule)
ptp_schedule_worker(cpts->ptp_clock, 0);
return ret;
}
+static int am65_cpts_fifo_read(struct am65_cpts *cpts)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&cpts->lock, flags);
+ ret = __am65_cpts_fifo_read(cpts);
+ spin_unlock_irqrestore(&cpts->lock, flags);
+
+ return ret;
+}
+
static u64 am65_cpts_gettime(struct am65_cpts *cpts,
struct ptp_system_timestamp *sts)
{
@@ -906,6 +913,69 @@ static int am65_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
return 1;
}
+static u64 am65_cpts_find_rx_ts(struct am65_cpts *cpts, u32 skb_mtype_seqid)
+{
+ struct list_head *this, *next;
+ struct am65_cpts_event *event;
+ unsigned long flags;
+ u32 mtype_seqid;
+ u64 ns = 0;
+
+ spin_lock_irqsave(&cpts->lock, flags);
+ __am65_cpts_fifo_read(cpts);
+ list_for_each_safe(this, next, &cpts->events) {
+ event = list_entry(this, struct am65_cpts_event, list);
+ if (time_after(jiffies, event->tmo)) {
+ list_move(&event->list, &cpts->pool);
+ continue;
+ }
+
+ mtype_seqid = event->event1 &
+ (AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK |
+ AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK |
+ AM65_CPTS_EVENT_1_EVENT_TYPE_MASK);
+
+ if (mtype_seqid == skb_mtype_seqid) {
+ ns = event->timestamp;
+ list_move(&event->list, &cpts->pool);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&cpts->lock, flags);
+
+ return ns;
+}
+
+void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb)
+{
+ struct am65_cpts_skb_cb_data *skb_cb = (struct am65_cpts_skb_cb_data *)skb->cb;
+ struct skb_shared_hwtstamps *ssh;
+ int ret;
+ u64 ns;
+
+ /* am65_cpts_rx_timestamp() is called before eth_type_trans(), so
+ * skb MAC Hdr properties are not configured yet. Hence need to
+ * reset skb MAC header here
+ */
+ skb_reset_mac_header(skb);
+ ret = am65_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+ if (!ret)
+ return; /* if not PTP class packet */
+
+ skb_cb->skb_mtype_seqid |= (AM65_CPTS_EV_RX << AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT);
+
+ dev_dbg(cpts->dev, "%s mtype seqid %08x\n", __func__, skb_cb->skb_mtype_seqid);
+
+ ns = am65_cpts_find_rx_ts(cpts, skb_cb->skb_mtype_seqid);
+ if (!ns)
+ return;
+
+ ssh = skb_hwtstamps(skb);
+ memset(ssh, 0, sizeof(*ssh));
+ ssh->hwtstamp = ns_to_ktime(ns);
+}
+EXPORT_SYMBOL_GPL(am65_cpts_rx_timestamp);
+
/**
* am65_cpts_tx_timestamp - save tx packet for timestamping
* @cpts: cpts handle
diff --git a/drivers/net/ethernet/ti/am65-cpts.h b/drivers/net/ethernet/ti/am65-cpts.h
index 6e14df0be113..90296968a75c 100644
--- a/drivers/net/ethernet/ti/am65-cpts.h
+++ b/drivers/net/ethernet/ti/am65-cpts.h
@@ -22,6 +22,7 @@ void am65_cpts_release(struct am65_cpts *cpts);
struct am65_cpts *am65_cpts_create(struct device *dev, void __iomem *regs,
struct device_node *node);
int am65_cpts_phc_index(struct am65_cpts *cpts);
+void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en);
@@ -48,6 +49,11 @@ static inline int am65_cpts_phc_index(struct am65_cpts *cpts)
return -1;
}
+static inline void am65_cpts_rx_timestamp(struct am65_cpts *cpts,
+ struct sk_buff *skb)
+{
+}
+
static inline void am65_cpts_tx_timestamp(struct am65_cpts *cpts,
struct sk_buff *skb)
{
--
2.34.1