igc: Add support for PTP .getcyclesx64()

Add support for using Timer 1 (i225/i226 have 4 timer registers) as a
free-running clock (the "cycles" clock) in addition to Timer 0 (the
default, "adjustable clock"). The objective is to allow taprio/etf
offloading to coexist with PTP vclocks.

Besides the implementation of .getcyclesx64() for i225/i226, to keep
timestamping working when vclocks are in use, we also need to add
support for TX and RX timestamping using the free running timer, when
the requesting socket is bound to a vclock.

On the RX side, i225/i226 can be configured to store the values of two
timers in the received packet metadata area, so it's a matter of
configuring the right registers and retrieving the right timestamp.

The TX is a bit more involved because the hardware stores a single
timestamp (with the selected timer in the TX descriptor) into one of
the timestamp registers.

Note some changes at how the timestamps are done for RX, the
conversion and adjustment of timestamps are now done closer to the
consumption of the timestamp instead of near the reception.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index f48f82d5e274..ac7c861e83a0 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -81,6 +81,21 @@ struct igc_tx_timestamp_request {
 	u32 flags;             /* flags that should be added to the tx_buffer */
 };
 
+struct igc_inline_rx_tstamps {
+	/* Timestamps are saved in little endian at the beginning of the packet
+	 * buffer following the layout:
+	 *
+	 * DWORD: | 0              | 1              | 2              | 3              |
+	 * Field: | Timer1 SYSTIML | Timer1 SYSTIMH | Timer0 SYSTIML | Timer0 SYSTIMH |
+	 *
+	 * SYSTIML holds the nanoseconds part while SYSTIMH holds the seconds
+	 * part of the timestamp.
+	 *
+	 */
+	__le32 timer1[2];
+	__le32 timer0[2];
+};
+
 struct igc_ring_container {
 	struct igc_ring *ring;          /* pointer to linked list of rings */
 	unsigned int total_bytes;       /* total bytes processed this int */
@@ -261,6 +276,8 @@ struct igc_adapter {
 	unsigned int ptp_flags;
 	/* System time value lock */
 	spinlock_t tmreg_lock;
+	/* Free-running timer lock */
+	spinlock_t free_timer_lock;
 	struct cyclecounter cc;
 	struct timecounter tc;
 	struct timespec64 prev_ptp_time; /* Pre-reset PTP clock */
@@ -469,6 +486,8 @@ enum igc_tx_flags {
 	IGC_TX_FLAGS_TSTAMP_1	= 0x100,
 	IGC_TX_FLAGS_TSTAMP_2	= 0x200,
 	IGC_TX_FLAGS_TSTAMP_3	= 0x400,
+
+	IGC_TX_FLAGS_TSTAMP_TIMER_1 = 0x800,
 };
 
 enum igc_boards {
@@ -531,7 +550,7 @@ struct igc_rx_buffer {
 struct igc_xdp_buff {
 	struct xdp_buff xdp;
 	union igc_adv_rx_desc *rx_desc;
-	ktime_t rx_ts; /* data indication bit IGC_RXDADV_STAT_TSIP */
+	struct igc_inline_rx_tstamps *rx_ts; /* data indication bit IGC_RXDADV_STAT_TSIP */
 };
 
 struct igc_q_vector {