[PATCH net-next 2/2] bnxt_en: Retry for TX timestamp from FW until timeout specified

[Michael Chan <michael.chan@broadcom.com>]

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From: Pavan Chebbi <pavan.chebbi@broadcom.com>

Use the ptp_tx_timeout devlink parameter introduced in the previous
patch to retry querying TX timestamp, up to the timeout specified.
Firmware supports timeout values up to 65535 microseconds.  The
driver will set this firmware timeout value according to the
ptp_tx_timeout parameter.  If the ptp_tx_timeout value exceeds
the maximum firmware value, the driver will retry in the context
of bnxt_ptp_ts_aux_work().

Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 Documentation/networking/devlink/bnxt.rst     |  7 +++++++
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c | 19 ++++++++++++++++---
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h |  4 +++-
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/Documentation/networking/devlink/bnxt.rst b/Documentation/networking/devlink/bnxt.rst
index a4fb27663cd6..48833c190c5b 100644
--- a/Documentation/networking/devlink/bnxt.rst
+++ b/Documentation/networking/devlink/bnxt.rst
@@ -41,6 +41,13 @@ parameters.
      - Generic Routing Encapsulation (GRE) version check will be enabled in
        the device. If disabled, the device will skip the version check for
        incoming packets.
+   * - ``ptp_tx_timeout``
+     - u32
+     - Runtime
+     - PTP Transmit timestamp timeout value in milliseconds. The default
+       value is 1000 and the maximum value is 5000. Use a higher value
+       on a busy network to prevent timeout retrieving the PTP Transmit
+       timestamp.
 
 Info versions
 =============
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
index 4b50b07b9771..a05b50162e9e 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
@@ -122,10 +122,14 @@ static int bnxt_hwrm_port_ts_query(struct bnxt *bp, u32 flags, u64 *ts)
 	req->flags = cpu_to_le32(flags);
 	if ((flags & PORT_TS_QUERY_REQ_FLAGS_PATH) ==
 	    PORT_TS_QUERY_REQ_FLAGS_PATH_TX) {
+		struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
+		u32 tmo_us = ptp->txts_tmo * 1000;
+
 		req->enables = cpu_to_le16(BNXT_PTP_QTS_TX_ENABLES);
-		req->ptp_seq_id = cpu_to_le32(bp->ptp_cfg->tx_seqid);
-		req->ptp_hdr_offset = cpu_to_le16(bp->ptp_cfg->tx_hdr_off);
-		req->ts_req_timeout = cpu_to_le16(BNXT_PTP_QTS_TIMEOUT);
+		req->ptp_seq_id = cpu_to_le32(ptp->tx_seqid);
+		req->ptp_hdr_offset = cpu_to_le16(ptp->tx_hdr_off);
+		tmo_us = min(tmo_us, BNXT_PTP_QTS_MAX_TMO_US);
+		req->ts_req_timeout = cpu_to_le16(tmo_us);
 	}
 	resp = hwrm_req_hold(bp, req);
 
@@ -675,6 +679,8 @@ static void bnxt_stamp_tx_skb(struct bnxt *bp, struct sk_buff *skb)
 	u64 ts = 0, ns = 0;
 	int rc;
 
+	if (!ptp->txts_pending)
+		ptp->abs_txts_tmo = jiffies + msecs_to_jiffies(ptp->txts_tmo);
 	rc = bnxt_hwrm_port_ts_query(bp, PORT_TS_QUERY_REQ_FLAGS_PATH_TX, &ts);
 	if (!rc) {
 		memset(&timestamp, 0, sizeof(timestamp));
@@ -684,6 +690,10 @@ static void bnxt_stamp_tx_skb(struct bnxt *bp, struct sk_buff *skb)
 		timestamp.hwtstamp = ns_to_ktime(ns);
 		skb_tstamp_tx(ptp->tx_skb, &timestamp);
 	} else {
+		if (!time_after_eq(jiffies, ptp->abs_txts_tmo)) {
+			ptp->txts_pending = true;
+			return;
+		}
 		netdev_warn_once(bp->dev,
 				 "TS query for TX timer failed rc = %x\n", rc);
 	}
@@ -691,6 +701,7 @@ static void bnxt_stamp_tx_skb(struct bnxt *bp, struct sk_buff *skb)
 	dev_kfree_skb_any(ptp->tx_skb);
 	ptp->tx_skb = NULL;
 	atomic_inc(&ptp->tx_avail);
+	ptp->txts_pending = false;
 }
 
 static long bnxt_ptp_ts_aux_work(struct ptp_clock_info *ptp_info)
@@ -714,6 +725,8 @@ static long bnxt_ptp_ts_aux_work(struct ptp_clock_info *ptp_info)
 		spin_unlock_bh(&ptp->ptp_lock);
 		ptp->next_overflow_check = now + BNXT_PHC_OVERFLOW_PERIOD;
 	}
+	if (ptp->txts_pending)
+		return 0;
 	return HZ;
 }
 
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
index ee977620d33e..bfb165d2b365 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
@@ -24,7 +24,7 @@
 
 #define BNXT_PTP_DFLT_TX_TMO	1000 /* ms */
 #define BNXT_PTP_MAX_TX_TMO	5000 /* ms */
-#define BNXT_PTP_QTS_TIMEOUT	1000
+#define BNXT_PTP_QTS_MAX_TMO_US	65535
 #define BNXT_PTP_QTS_TX_ENABLES	(PORT_TS_QUERY_REQ_ENABLES_PTP_SEQ_ID |	\
 				 PORT_TS_QUERY_REQ_ENABLES_TS_REQ_TIMEOUT | \
 				 PORT_TS_QUERY_REQ_ENABLES_PTP_HDR_OFFSET)
@@ -117,12 +117,14 @@ struct bnxt_ptp_cfg {
 					 BNXT_PTP_MSG_PDELAY_REQ |	\
 					 BNXT_PTP_MSG_PDELAY_RESP)
 	u8			tx_tstamp_en:1;
+	u8			txts_pending:1;
 	int			rx_filter;
 	u32			tstamp_filters;
 
 	u32			refclk_regs[2];
 	u32			refclk_mapped_regs[2];
 	u32			txts_tmo;
+	unsigned long		abs_txts_tmo;
 };
 
 #if BITS_PER_LONG == 32
-- 
2.30.1


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