Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue

Tony Nguyen says:

====================
Intel Wired LAN Driver Updates 2022-12-08 (ice)

Jacob Keller says:

This series of patches primarily consists of changes to fix some corner
cases that can cause Tx timestamp failures. The issues were discovered and
reported by Siddaraju DH and primarily affect E822 hardware, though this
series also includes some improvements that affect E810 hardware as well.

The primary issue is regarding the way that E822 determines when to generate
timestamp interrupts. If the driver reads timestamp indexes which do not
have a valid timestamp, the E822 interrupt tracking logic can get stuck.
This is due to the way that E822 hardware tracks timestamp index reads
internally. I was previously unaware of this behavior as it is significantly
different in E810 hardware.

Most of the fixes target refactors to ensure that the ice driver does not
read timestamp indexes which are not valid on E822 hardware. This is done by
using the Tx timestamp ready bitmap register from the PHY. This register
indicates what timestamp indexes have outstanding timestamps waiting to be
captured.

Care must be taken in all cases where we read the timestamp registers, and
thus all flows which might have read these registers are refactored. The
ice_ptp_tx_tstamp function is modified to consolidate as much of the logic
relating to these registers as possible. It now handles discarding stale
timestamps which are old or which occurred after a PHC time update. This
replaces previously standalone thread functions like the periodic work
function and the ice_ptp_flush_tx_tracker function.

In addition, some minor cleanups noticed while writing these refactors are
included.

The remaining patches refactor the E822 implementation to remove the
"bypass" mode for timestamps. The E822 hardware has the ability to provide a
more precise timestamp by making use of measurements of the precise way that
packets flow through the hardware pipeline. These measurements are known as
"Vernier" calibration. The "bypass" mode disables many of these measurements
in favor of a faster start up time for Tx and Rx timestamping. Instead, once
these measurements were captured, the driver tries to reconfigure the PHY to
enable the vernier calibrations.

Unfortunately this recalibration does not work. Testing indicates that the
PHY simply remains in bypass mode without the increased timestamp precision.
Remove the attempt at recalibration and always use vernier mode. This has
one disadvantage that Tx and Rx timestamps cannot begin until after at least
one packet of that type goes through the hardware pipeline. Because of this,
further refactor the driver to separate Tx and Rx vernier calibration.
Complete the Tx and Rx independently, enabling the appropriate type of
timestamp as soon as the relevant packet has traversed the hardware
pipeline. This was reported by Milena Olech.

Note that although these might be considered "bug fixes", the required
changes in order to appropriately resolve these issues is large. Thus it
does not feel suitable to send this series to net.

* '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue:
  ice: reschedule ice_ptp_wait_for_offset_valid during reset
  ice: make Tx and Rx vernier offset calibration independent
  ice: only check set bits in ice_ptp_flush_tx_tracker
  ice: handle flushing stale Tx timestamps in ice_ptp_tx_tstamp
  ice: cleanup allocations in ice_ptp_alloc_tx_tracker
  ice: protect init and calibrating check in ice_ptp_request_ts
  ice: synchronize the misc IRQ when tearing down Tx tracker
  ice: check Tx timestamp memory register for ready timestamps
  ice: handle discarding old Tx requests in ice_ptp_tx_tstamp
  ice: always call ice_ptp_link_change and make it void
  ice: fix misuse of "link err" with "link status"
  ice: Reset TS memory for all quads
  ice: Remove the E822 vernier "bypass" logic
  ice: Use more generic names for ice_ptp_tx fields
====================

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

1 files changed, 25 insertions, 14 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
index 028349295b71..9cda2f43e0e5 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.h
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
@@ -93,9 +93,14 @@ struct ice_perout_channel {
  * we discard old requests that were not fulfilled within a 2 second time
  * window.
  * Timestamp values in the PHY are read only and do not get cleared except at
- * hardware reset or when a new timestamp value is captured. The cached_tstamp
- * field is used to detect the case where a new timestamp has not yet been
- * captured, ensuring that we avoid sending stale timestamp data to the stack.
+ * hardware reset or when a new timestamp value is captured.
+ *
+ * Some PHY types do not provide a "ready" bitmap indicating which timestamp
+ * indexes are valid. In these cases, we use a cached_tstamp to keep track of
+ * 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.
  */
 struct ice_tx_tstamp {
 	struct sk_buff *skb;
@@ -105,30 +110,35 @@ struct ice_tx_tstamp {
 
 /**
  * struct ice_ptp_tx - Tracking structure for all Tx timestamp requests on a port
- * @lock: lock to prevent concurrent write to in_use bitmap
+ * @lock: lock to prevent concurrent access to fields of this struct
  * @tstamps: array of len to store outstanding requests
  * @in_use: bitmap of len to indicate which slots are in use
- * @quad: which quad the timestamps are captured in
- * @quad_offset: offset into timestamp block of the quad to get the real index
+ * @stale: bitmap of len to indicate slots which have stale timestamps
+ * @block: which memory block (quad or port) the timestamps are captured in
+ * @offset: offset into timestamp block to get the real index
  * @len: length of the tstamps and in_use fields.
  * @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
  */
 struct ice_ptp_tx {
 	spinlock_t lock; /* lock protecting in_use bitmap */
 	struct ice_tx_tstamp *tstamps;
 	unsigned long *in_use;
-	u8 quad;
-	u8 quad_offset;
+	unsigned long *stale;
+	u8 block;
+	u8 offset;
 	u8 len;
-	u8 init;
-	u8 calibrating;
+	u8 init : 1;
+	u8 calibrating : 1;
+	u8 verify_cached : 1;
 };
 
 /* Quad and port information for initializing timestamp blocks */
 #define INDEX_PER_QUAD			64
-#define INDEX_PER_PORT			(INDEX_PER_QUAD / ICE_PORTS_PER_QUAD)
+#define INDEX_PER_PORT_E822		16
+#define INDEX_PER_PORT_E810		64
 
 /**
  * struct ice_ptp_port - data used to initialize an external port for PTP
@@ -256,7 +266,7 @@ void ice_ptp_reset(struct ice_pf *pf);
 void ice_ptp_prepare_for_reset(struct ice_pf *pf);
 void ice_ptp_init(struct ice_pf *pf);
 void ice_ptp_release(struct ice_pf *pf);
-int ice_ptp_link_change(struct ice_pf *pf, u8 port, bool linkup);
+void ice_ptp_link_change(struct ice_pf *pf, u8 port, bool linkup);
 #else /* IS_ENABLED(CONFIG_PTP_1588_CLOCK) */
 static inline int ice_ptp_set_ts_config(struct ice_pf *pf, struct ifreq *ifr)
 {
@@ -291,7 +301,8 @@ static inline void ice_ptp_reset(struct ice_pf *pf) { }
 static inline void ice_ptp_prepare_for_reset(struct ice_pf *pf) { }
 static inline void ice_ptp_init(struct ice_pf *pf) { }
 static inline void ice_ptp_release(struct ice_pf *pf) { }
-static inline int ice_ptp_link_change(struct ice_pf *pf, u8 port, bool linkup)
-{ return 0; }
+static inline void ice_ptp_link_change(struct ice_pf *pf, u8 port, bool linkup)
+{
+}
 #endif /* IS_ENABLED(CONFIG_PTP_1588_CLOCK) */
 #endif /* _ICE_PTP_H_ */