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Subject[PATCH net-next v4 1/4] net: phy: add an option to disable EEE advertisement
Date

This patch adds an option to disable EEE advertisement in the generic PHY
by providing a mask of prohibited modes corresponding to the value found in
the MDIO_AN_EEE_ADV register.

On some platforms, PHY Low power idle seems to be causing issues, even
breaking the link some cases. The patch provides a convenient way for these
platforms to disable EEE advertisement and work around the issue.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
---
drivers/net/phy/phy.c | 3 ++
drivers/net/phy/phy_device.c | 80 +++++++++++++++++++++++++++++++++++++++-----
include/linux/phy.h | 3 ++
3 files changed, 77 insertions(+), 9 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 73adbaa9ac86..a3981cc6448a 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -1396,6 +1396,9 @@ int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data)
{
int val = ethtool_adv_to_mmd_eee_adv_t(data->advertised);

+ /* Mask prohibited EEE modes */
+ val &= ~phydev->eee_broken_modes;
+
phy_write_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN, val);

return 0;
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index ba86c191a13e..cb4aca205cf8 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1121,6 +1121,43 @@ static int genphy_config_advert(struct phy_device *phydev)
}

/**
+ * genphy_config_eee_advert - disable unwanted eee mode advertisement
+ * @phydev: target phy_device struct
+ *
+ * Description: Writes MDIO_AN_EEE_ADV after disabling unsupported energy
+ * efficent ethernet modes. Returns 0 if the PHY's advertisement hasn't
+ * changed, and 1 if it has changed.
+ */
+static int genphy_config_eee_advert(struct phy_device *phydev)
+{
+ int broken = phydev->eee_broken_modes;
+ int old_adv, adv;
+
+ /* Nothing to disable */
+ if (!broken)
+ return 0;
+
+ /* If the following call fails, we assume that EEE is not
+ * supported by the phy. If we read 0, EEE is not advertised
+ * In both case, we don't need to continue
+ */
+ adv = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN);
+ if (adv <= 0)
+ return 0;
+
+ old_adv = adv;
+ adv &= ~broken;
+
+ /* Advertising remains unchanged with the broken mask */
+ if (old_adv == adv)
+ return 0;
+
+ phy_write_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN, adv);
+
+ return 1;
+}
+
+/**
* genphy_setup_forced - configures/forces speed/duplex from @phydev
* @phydev: target phy_device struct
*
@@ -1178,15 +1215,20 @@ EXPORT_SYMBOL(genphy_restart_aneg);
*/
int genphy_config_aneg(struct phy_device *phydev)
{
- int result;
+ int err, changed;
+
+ changed = genphy_config_eee_advert(phydev);

if (AUTONEG_ENABLE != phydev->autoneg)
return genphy_setup_forced(phydev);

- result = genphy_config_advert(phydev);
- if (result < 0) /* error */
- return result;
- if (result == 0) {
+ err = genphy_config_advert(phydev);
+ if (err < 0) /* error */
+ return err;
+
+ changed |= err;
+
+ if (changed == 0) {
/* Advertisement hasn't changed, but maybe aneg was never on to
* begin with? Or maybe phy was isolated?
*/
@@ -1196,16 +1238,16 @@ int genphy_config_aneg(struct phy_device *phydev)
return ctl;

if (!(ctl & BMCR_ANENABLE) || (ctl & BMCR_ISOLATE))
- result = 1; /* do restart aneg */
+ changed = 1; /* do restart aneg */
}

/* Only restart aneg if we are advertising something different
* than we were before.
*/
- if (result > 0)
- result = genphy_restart_aneg(phydev);
+ if (changed > 0)
+ return genphy_restart_aneg(phydev);

- return result;
+ return 0;
}
EXPORT_SYMBOL(genphy_config_aneg);

@@ -1563,6 +1605,21 @@ static void of_set_phy_supported(struct phy_device *phydev)
__set_phy_supported(phydev, max_speed);
}

+static void of_set_phy_eee_broken(struct phy_device *phydev)
+{
+ struct device_node *node = phydev->mdio.dev.of_node;
+ u32 broken;
+
+ if (!IS_ENABLED(CONFIG_OF_MDIO))
+ return;
+
+ if (!node)
+ return;
+
+ if (!of_property_read_u32(node, "eee-broken-modes", &broken))
+ phydev->eee_broken_modes = broken;
+}
+
/**
* phy_probe - probe and init a PHY device
* @dev: device to probe and init
@@ -1600,6 +1657,11 @@ static int phy_probe(struct device *dev)
of_set_phy_supported(phydev);
phydev->advertising = phydev->supported;

+ /* Get the EEE modes we want to prohibit. We will ask
+ * the PHY stop advertising these mode later on
+ */
+ of_set_phy_eee_broken(phydev);
+
/* Set the state to READY by default */
phydev->state = PHY_READY;

diff --git a/include/linux/phy.h b/include/linux/phy.h
index edde28ce163a..b53177fd38af 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -417,6 +417,9 @@ struct phy_device {
u32 advertising;
u32 lp_advertising;

+ /* Energy efficient ethernet modes which should be prohibited */
+ u32 eee_broken_modes;
+
int autoneg;

int link_timeout;
--
2.7.4
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