Re: [PATCH v7 net-next 6/8] net: ethernet: ti: am65-cpsw-qos: Add Frame Preemption MAC Merge support

[Roger Quadros <rogerq@kernel.org>]

On 07/12/2023 17:24, Vladimir Oltean wrote:
> On Fri, Dec 01, 2023 at 03:58:00PM +0200, Roger Quadros wrote:
>> - now passes all ethtool_mm.sh kselftests (patch 8 required)
> 
> There's another problem with your patch set, leading to the
> traffic_test() selftest passing with the "emac" and "pmac" argument when
> it shouldn't.
> 
> Drivers which implement frame preemption are supposed to be prepared to
> distinguish, in their ethtool get_eth_mac_stats() method, between
> ETHTOOL_MAC_STATS_SRC_EMAC, ETHTOOL_MAC_STATS_SRC_PMAC and
> ETHTOOL_MAC_STATS_SRC_AGGREGATE. You don't, so you report the same thing
> everywhere, which is incorrect, and it also fools the selftest.
> 
> I would like you to figure out which source are your stats coming from,
> reject everything else, and edit the selftest to do something sensible
> for your hardware. If it's as I suspect and the reported counters are
> eMAC+pMAC aggregates, then I guess the most sensible thing to do would
> be to probe the device with an ethtool -S --src pmac at the beginning of
> the test, see what it reports, and if we don't get pMAC counters from
> it, fall back to aggregate ones during calls to traffic_test().

Thanks for the catch.

How do the below 2 patches look to resolve this?

From af2a8503dc04c54d6eaf50954628009aba54e2c8 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq@kernel.org>
Date: Fri, 8 Dec 2023 15:11:06 +0200
Subject: [PATCH] net: ethernet: ti: am65-cpsw: Fix get_eth_mac_stats

We do not support individual stats for PMAC and EMAC so
report only aggregate stats.

Fixes: 67372d7a85fcd ("net: ethernet: am65-cpsw: Add standard Ethernet MAC stats to ethtool")
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 37 ++++++++++++---------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
index 44e01d68db39..934b03382508 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
@@ -671,21 +671,28 @@ static void am65_cpsw_get_eth_mac_stats(struct net_device *ndev,
 
 	stats = port->stat_base;
 
-	s->FramesTransmittedOK = readl_relaxed(&stats->tx_good_frames);
-	s->SingleCollisionFrames = readl_relaxed(&stats->tx_single_coll_frames);
-	s->MultipleCollisionFrames = readl_relaxed(&stats->tx_mult_coll_frames);
-	s->FramesReceivedOK = readl_relaxed(&stats->rx_good_frames);
-	s->FrameCheckSequenceErrors = readl_relaxed(&stats->rx_crc_errors);
-	s->AlignmentErrors = readl_relaxed(&stats->rx_align_code_errors);
-	s->OctetsTransmittedOK = readl_relaxed(&stats->tx_octets);
-	s->FramesWithDeferredXmissions = readl_relaxed(&stats->tx_deferred_frames);
-	s->LateCollisions = readl_relaxed(&stats->tx_late_collisions);
-	s->CarrierSenseErrors = readl_relaxed(&stats->tx_carrier_sense_errors);
-	s->OctetsReceivedOK = readl_relaxed(&stats->rx_octets);
-	s->MulticastFramesXmittedOK = readl_relaxed(&stats->tx_multicast_frames);
-	s->BroadcastFramesXmittedOK = readl_relaxed(&stats->tx_broadcast_frames);
-	s->MulticastFramesReceivedOK = readl_relaxed(&stats->rx_multicast_frames);
-	s->BroadcastFramesReceivedOK = readl_relaxed(&stats->rx_broadcast_frames);
+        switch (s->src) {
+	case ETHTOOL_MAC_STATS_SRC_AGGREGATE:
+		s->FramesTransmittedOK = readl_relaxed(&stats->tx_good_frames);
+		s->SingleCollisionFrames = readl_relaxed(&stats->tx_single_coll_frames);
+		s->MultipleCollisionFrames = readl_relaxed(&stats->tx_mult_coll_frames);
+		s->FramesReceivedOK = readl_relaxed(&stats->rx_good_frames);
+		s->FrameCheckSequenceErrors = readl_relaxed(&stats->rx_crc_errors);
+		s->AlignmentErrors = readl_relaxed(&stats->rx_align_code_errors);
+		s->OctetsTransmittedOK = readl_relaxed(&stats->tx_octets);
+		s->FramesWithDeferredXmissions = readl_relaxed(&stats->tx_deferred_frames);
+		s->LateCollisions = readl_relaxed(&stats->tx_late_collisions);
+		s->CarrierSenseErrors = readl_relaxed(&stats->tx_carrier_sense_errors);
+		s->OctetsReceivedOK = readl_relaxed(&stats->rx_octets);
+		s->MulticastFramesXmittedOK = readl_relaxed(&stats->tx_multicast_frames);
+		s->BroadcastFramesXmittedOK = readl_relaxed(&stats->tx_broadcast_frames);
+		s->MulticastFramesReceivedOK = readl_relaxed(&stats->rx_multicast_frames);
+		s->BroadcastFramesReceivedOK = readl_relaxed(&stats->rx_broadcast_frames);
+		break;
+	default:
+		break;
+	}
 };
 
 static int am65_cpsw_get_ethtool_ts_info(struct net_device *ndev,

base-commit: a78e0a2c4353d6c100e45c5ef738113bf2d0fda5
-- 
2.34.1




From 0b20d8b8ef110d886396ee2486f3a9e20170cc85 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq@kernel.org>
Date: Fri, 8 Dec 2023 15:38:57 +0200
Subject: [PATCH] selftests: forwarding: ethtool_mm: support devices that don't
 support pmac stats

Some devices do not support individual 'pmac' and 'emac' stats.
For such devices, resort to 'aggregate' stats.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 tools/testing/selftests/net/forwarding/ethtool_mm.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/testing/selftests/net/forwarding/ethtool_mm.sh b/tools/testing/selftests/net/forwarding/ethtool_mm.sh
index 6212913f4ad1..e3f2e62029ca 100755
--- a/tools/testing/selftests/net/forwarding/ethtool_mm.sh
+++ b/tools/testing/selftests/net/forwarding/ethtool_mm.sh
@@ -26,6 +26,13 @@ traffic_test()
 	local delta=
 
 	before=$(ethtool_std_stats_get $if "eth-mac" "FramesTransmittedOK" $src)
+	# some devices don't support individual pmac/emac stats,
+	# use aggregate stats for them.
+        if [ "$before" == null ]; then
+                src="aggregate"
+                before=$(ethtool_std_stats_get $if "eth-mac" "FramesTransmittedOO
+K" $src)
+        fi
 
 	$MZ $if -q -c $num_pkts -p 64 -b bcast -t ip -R $PREEMPTIBLE_PRIO
 

base-commit: af2a8503dc04c54d6eaf50954628009aba54e2c8
-- 
2.34.1

-- 
cheers,
-roger