netdev - [PATCH] net: mvneta: speed down the PHY, if WoL used, to save energy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <32495177.Bv3dSJjO3Z@tool>
Date:   Tue, 12 May 2020 19:59:48 +0200
From:   Daniel González Cabanelas <dgcbueu@...il.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, thomas.petazzoni@...tlin.com
Subject: [PATCH] net: mvneta: speed down the PHY, if WoL used, to save energy

Some PHYs connected to this ethernet hardware support the WoL feature.
But when WoL is enabled and the machine is powered off, the PHY remains
waiting for a magic packet at max speed (i.e. 1Gbps), which is a waste of
energy.

Slow down the PHY speed before stopping the ethernet if WoL is enabled,
and save some energy while the machine is powered off or sleeping.

Tested using an Armada 370 based board (LS421DE) equipped with a Marvell
88E1518 PHY.

Signed-off-by: Daniel González Cabanelas <dgcbueu@...il.com>
---
 drivers/net/ethernet/marvell/mvneta.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 5188977095..e0e9e56830 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -3561,6 +3561,10 @@ static void mvneta_start_dev(struct mvneta_port *pp)
 		    MVNETA_CAUSE_LINK_CHANGE);
 
 	phylink_start(pp->phylink);
+
+	/* We may have called phy_speed_down before */
+	phy_speed_up(pp->dev->phydev);
+
 	netif_tx_start_all_queues(pp->dev);
 }
 
@@ -3568,6 +3572,9 @@ static void mvneta_stop_dev(struct mvneta_port *pp)
 {
 	unsigned int cpu;
 
+	if (device_may_wakeup(&pp->dev->dev))
+		phy_speed_down(pp->dev->phydev, false);
+
 	phylink_stop(pp->phylink);
 
 	if (!pp->neta_armada3700) {
@@ -4040,6 +4047,10 @@ static int mvneta_mdio_probe(struct mvneta_port *pp)
 	phylink_ethtool_get_wol(pp->phylink, &wol);
 	device_set_wakeup_capable(&pp->dev->dev, !!wol.supported);
 
+	/* PHY WoL may be enabled but device wakeup disabled */
+	if (wol.supported)
+		device_set_wakeup_enable(&pp->dev->dev, !!wol.wolopts);
+
 	return err;
 }
 
-- 
2.26.2