Date: Wed, 20 Dec 2023 11:43:20 +0100
From: Karol Kolacinski <karol.kolacinski@...el.com>
To: intel-wired-lan@...ts.osuosl.org
Cc: netdev@...r.kernel.org,
	anthony.l.nguyen@...el.com,
	jesse.brandeburg@...el.com,
	Jacob Keller <jacob.e.keller@...el.com>,
	Karol Kolacinski <karol.kolacinski@...el.com>
Subject: [PATCH v3 iwl-next 3/6] ice: rename verify_cached to has_ready_bitmap

From: Jacob Keller <jacob.e.keller@...el.com>

The tx->verify_cached flag is used to inform the Tx timestamp tracking
code whether it needs to verify the cached Tx timestamp value against
a previous captured value. This is necessary on E810 hardware which does
not have a Tx timestamp ready bitmap.

In addition, we currently rely on the fact that the
ice_get_phy_tx_tstamp_ready() function returns all 1s for E810 hardware.
Instead of introducing a brand new flag, rename and verify_cached to
has_ready_bitmap, inverting the relevant checks.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Signed-off-by: Karol Kolacinski <karol.kolacinski@...el.com>
Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>
---
 drivers/net/ethernet/intel/ice/ice_ptp.c | 31 ++++++++++++------------
 drivers/net/ethernet/intel/ice/ice_ptp.h |  8 +++---
 2 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index c309d3fd5a4e..4b1b2c577df7 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -601,17 +601,13 @@ void ice_ptp_complete_tx_single_tstamp(struct ice_ptp_tx *tx)
 	/* Read the low 32 bit value */
 	raw_tstamp |= (u64)rd32(&pf->hw, PF_SB_ATQBAH);
 
-	/* For PHYs which don't implement a proper timestamp ready bitmap,
-	 * verify that the timestamp value is different from the last cached
-	 * timestamp. If it is not, skip this for now assuming it hasn't yet
-	 * been captured by hardware.
+	/* Devices using this interface always verify the timestamp differs
+	 * relative to the last cached timestamp value.
 	 */
-	if (!drop_ts && tx->verify_cached &&
-	    raw_tstamp == tx->tstamps[idx].cached_tstamp)
+	if (raw_tstamp == tx->tstamps[idx].cached_tstamp)
 		return;
 
-	if (tx->verify_cached && raw_tstamp)
-		tx->tstamps[idx].cached_tstamp = raw_tstamp;
+	tx->tstamps[idx].cached_tstamp = raw_tstamp;
 	clear_bit(idx, tx->in_use);
 	skb = tx->tstamps[idx].skb;
 	tx->tstamps[idx].skb = NULL;
@@ -701,9 +697,11 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
 	hw = &pf->hw;
 
 	/* Read the Tx ready status first */
-	err = ice_get_phy_tx_tstamp_ready(hw, tx->block, &tstamp_ready);
-	if (err)
-		return;
+	if (tx->has_ready_bitmap) {
+		err = ice_get_phy_tx_tstamp_ready(hw, tx->block, &tstamp_ready);
+		if (err)
+			return;
+	}
 
 	/* Drop packets if the link went down */
 	link_up = ptp_port->link_up;
@@ -731,7 +729,8 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
 		 * If we do not, the hardware logic for generating a new
 		 * interrupt can get stuck on some devices.
 		 */
-		if (!(tstamp_ready & BIT_ULL(phy_idx))) {
+		if (tx->has_ready_bitmap &&
+		    !(tstamp_ready & BIT_ULL(phy_idx))) {
 			if (drop_ts)
 				goto skip_ts_read;
 
@@ -751,7 +750,7 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
 		 * from the last cached timestamp. If it is not, skip this for
 		 * now assuming it hasn't yet been captured by hardware.
 		 */
-		if (!drop_ts && tx->verify_cached &&
+		if (!drop_ts && !tx->has_ready_bitmap &&
 		    raw_tstamp == tx->tstamps[idx].cached_tstamp)
 			continue;
 
@@ -761,7 +760,7 @@ static void ice_ptp_process_tx_tstamp(struct ice_ptp_tx *tx)
 
 skip_ts_read:
 		spin_lock_irqsave(&tx->lock, flags);
-		if (tx->verify_cached && raw_tstamp)
+		if (!tx->has_ready_bitmap && raw_tstamp)
 			tx->tstamps[idx].cached_tstamp = raw_tstamp;
 		clear_bit(idx, tx->in_use);
 		skb = tx->tstamps[idx].skb;
@@ -1014,7 +1013,7 @@ ice_ptp_init_tx_e82x(struct ice_pf *pf, struct ice_ptp_tx *tx, u8 port)
 	tx->block = port / ICE_PORTS_PER_QUAD;
 	tx->offset = (port % ICE_PORTS_PER_QUAD) * INDEX_PER_PORT_E82X;
 	tx->len = INDEX_PER_PORT_E82X;
-	tx->verify_cached = 0;
+	tx->has_ready_bitmap = 1;
 
 	return ice_ptp_alloc_tx_tracker(tx);
 }
@@ -1037,7 +1036,7 @@ ice_ptp_init_tx_e810(struct ice_pf *pf, struct ice_ptp_tx *tx)
 	 * verify new timestamps against cached copy of the last read
 	 * timestamp.
 	 */
-	tx->verify_cached = 1;
+	tx->has_ready_bitmap = 0;
 
 	return ice_ptp_alloc_tx_tracker(tx);
 }
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
index 7b748f22e6f7..c8549508359a 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.h
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
@@ -100,7 +100,7 @@ struct ice_perout_channel {
  * the last timestamp we read for a given index. If the current timestamp
  * value is the same as the cached value, we assume a new timestamp hasn't
  * been captured. This avoids reporting stale timestamps to the stack. This is
- * only done if the verify_cached flag is set in ice_ptp_tx structure.
+ * only done if the has_ready_bitmap flag is not set in ice_ptp_tx structure.
  */
 struct ice_tx_tstamp {
 	struct sk_buff *skb;
@@ -130,7 +130,9 @@ enum ice_tx_tstamp_work {
  * @init: if true, the tracker is initialized;
  * @calibrating: if true, the PHY is calibrating the Tx offset. During this
  *               window, timestamps are temporarily disabled.
- * @verify_cached: if true, verify new timestamp differs from last read value
+ * @has_ready_bitmap: if true, the hardware has a valid Tx timestamp ready
+ *                    bitmap register. If false, fall back to verifying new
+ *                    timestamp values against previously cached copy.
  * @last_ll_ts_idx_read: index of the last LL TS read by the FW
  */
 struct ice_ptp_tx {
@@ -143,7 +145,7 @@ struct ice_ptp_tx {
 	u8 len;
 	u8 init : 1;
 	u8 calibrating : 1;
-	u8 verify_cached : 1;
+	u8 has_ready_bitmap : 1;
 	s8 last_ll_ts_idx_read;
 };
 
-- 
2.40.1

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