Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Yuezhen Luan <eggcar.luan@gmail.com>
To:     jesse.brandeburg@intel.com, anthony.l.nguyen@intel.com,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com
Cc:     intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, jacob.e.keller@intel.com,
        Yuezhen Luan <eggcar.luan@gmail.com>
Subject: [PATCHv3 net] igb: Fix extts capture value format for 82580/i354/i350
Date:   Fri,  2 Jun 2023 07:04:22 +0000
Message-Id: <20230602070422.1808-1-eggcar.luan@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

82580/i354/i350 features circle-counter-like timestamp registers
that are different with newer i210. The EXTTS capture value in
AUXTSMPx should be converted from raw circle counter value to
timestamp value in resolution of 1 nanosec by the driver.

This issue can be reproduced on i350 nics, connecting an 1PPS
signal to a SDP pin, and run 'ts2phc' command to read external
1PPS timestamp value. On i210 this works fine, but on i350 the
extts is not correctly converted.

The i350/i354/82580's SYSTIM and other timestamp registers are
40bit counters, presenting time range of 2^40 ns, that means these
registers overflows every about 1099s. This causes all these regs
can't be used directly in contrast to the newer i210/i211s.

The igb driver needs to convert these raw register values to
valid time stamp format by using kernel timecounter apis for i350s
families. Here the igb_extts() just forgot to do the convert.

Fixes: 38970eac41db ("igb: support EXTTS on 82580/i354/i350")
Signed-off-by: Yuezhen Luan <eggcar.luan@gmail.com>
---
V2 -> V3: Add 'Fixes' tag, and add 'net' tag in patch title
V1 -> V2: Fix typo in the source code, and add detailed explanation

 drivers/net/ethernet/intel/igb/igb_main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 58872a4c2..bb3db387d 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6947,6 +6947,7 @@ static void igb_extts(struct igb_adapter *adapter, int tsintr_tt)
 	struct e1000_hw *hw = &adapter->hw;
 	struct ptp_clock_event event;
 	struct timespec64 ts;
+	unsigned long flags;
 
 	if (pin < 0 || pin >= IGB_N_SDP)
 		return;
@@ -6954,9 +6955,12 @@ static void igb_extts(struct igb_adapter *adapter, int tsintr_tt)
 	if (hw->mac.type == e1000_82580 ||
 	    hw->mac.type == e1000_i354 ||
 	    hw->mac.type == e1000_i350) {
-		s64 ns = rd32(auxstmpl);
+		u64 ns = rd32(auxstmpl);
 
-		ns += ((s64)(rd32(auxstmph) & 0xFF)) << 32;
+		ns += ((u64)(rd32(auxstmph) & 0xFF)) << 32;
+		spin_lock_irqsave(&adapter->tmreg_lock, flags);
+		ns = timecounter_cyc2time(&adapter->tc, ns);
+		spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
 		ts = ns_to_timespec64(ns);
 	} else {
 		ts.tv_nsec = rd32(auxstmpl);
-- 
2.34.1