LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Antoine Tenart <antoine.tenart@bootlin.com>
To: davem@davemloft.net, andrew@lunn.ch, f.fainelli@gmail.com,
	hkallweit1@gmail.com
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	thomas.petazzoni@bootlin.com, nicolas.ferre@microchip.com,
	ludovic.desroches@microchip.com, alexandre.belloni@bootlin.com
Subject: [PATCH net-next] net: phy: micrel: add Asym Pause workaround
Date: Tue, 16 Apr 2019 12:10:20 +0200
Message-ID: <20190416101020.22149-1-antoine.tenart@bootlin.com> (raw)

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


             reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16 10:10 Antoine Tenart [this message]
2019-04-16 16:39 ` Andrew Lunn
2019-04-16 23:46 ` Florian Fainelli
2019-04-17  4:36 ` David Miller

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190416101020.22149-1-antoine.tenart@bootlin.com \
    --to=antoine.tenart@bootlin.com \
    --cc=alexandre.belloni@bootlin.com \
    --cc=andrew@lunn.ch \
    --cc=davem@davemloft.net \
    --cc=f.fainelli@gmail.com \
    --cc=hkallweit1@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=ludovic.desroches@microchip.com \
    --cc=netdev@vger.kernel.org \
    --cc=nicolas.ferre@microchip.com \
    --cc=thomas.petazzoni@bootlin.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox