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* [PATCH net-next] net: phy: micrel: add Asym Pause workaround
@ 2019-04-16 10:10 Antoine Tenart
  2019-04-16 16:39 ` Andrew Lunn
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Antoine Tenart @ 2019-04-16 10:10 UTC (permalink / raw)
  To: davem, andrew, f.fainelli, hkallweit1
  Cc: Antoine Tenart, netdev, linux-kernel, thomas.petazzoni,
	nicolas.ferre, ludovic.desroches, alexandre.belloni

The Micrel KSZ9031 PHY may fail to establish a link when the Asymmetric
Pause capability is set. This issue is described in a Silicon Errata
(DS80000691D or DS80000692D), which advises to always disable the
capability. This patch implements the workaround by defining a KSZ9031
specific get_feature callback to force the Asymmetric Pause capability
bit to be cleared.

This fixes issues where the link would not come up at boot time, or when
the Asym Pause bit was set later on.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
---
 drivers/net/phy/micrel.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index d6807b5bcd97..ddd6b6374d8c 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -738,6 +738,31 @@ static int ksz8873mll_read_status(struct phy_device *phydev)
 	return 0;
 }
 
+static int ksz9031_get_features(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = genphy_read_abilities(phydev);
+	if (ret < 0)
+		return ret;
+
+	/* Silicon Errata Sheet (DS80000691D or DS80000692D):
+	 * Whenever the device's Asymmetric Pause capability is set to 1,
+	 * link-up may fail after a link-up to link-down transition.
+	 *
+	 * Workaround:
+	 * Do not enable the Asymmetric Pause capability bit.
+	 */
+	linkmode_clear_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, phydev->supported);
+
+	/* We force setting the Pause capability as the core will force the
+	 * Asymmetric Pause capability to 1 otherwise.
+	 */
+	linkmode_set_bit(ETHTOOL_LINK_MODE_Pause_BIT, phydev->supported);
+
+	return 0;
+}
+
 static int ksz9031_read_status(struct phy_device *phydev)
 {
 	int err;
@@ -1052,9 +1077,9 @@ static struct phy_driver ksphy_driver[] = {
 	.phy_id		= PHY_ID_KSZ9031,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
 	.name		= "Micrel KSZ9031 Gigabit PHY",
-	/* PHY_GBIT_FEATURES */
 	.driver_data	= &ksz9021_type,
 	.probe		= kszphy_probe,
+	.get_features	= ksz9031_get_features,
 	.config_init	= ksz9031_config_init,
 	.soft_reset	= genphy_soft_reset,
 	.read_status	= ksz9031_read_status,
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2019-04-17  4:36 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-16 10:10 [PATCH net-next] net: phy: micrel: add Asym Pause workaround Antoine Tenart
2019-04-16 16:39 ` Andrew Lunn
2019-04-16 23:46 ` Florian Fainelli
2019-04-17  4:36 ` David Miller

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