[PATCH 4.2 27/30] net: phy: fixed_phy: handle link-down case

[PATCH 4.2 27/30] net: phy: fixed_phy: handle link-down case

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stas Sergeev <stsp@list.ru>

[ Upstream 868a4215be9a6d80548ccb74763b883dc99d32a2 in net-next tree,
  will be pushed to Linus very soon. ]

fixed_phy_register() currently hardcodes the fixed PHY link to 1, and
expects to find a "speed" parameter to provide correct information
towards the fixed PHY consumer.

In a subsequent change, where we allow "managed" (e.g: (RS)GMII in-band
status auto-negotiation) fixed PHYs, none of these parameters can be
provided since they will be auto-negotiated, hence, we just provide a
zero-initialized fixed_phy_status to fixed_phy_register() which makes it
fail when we call fixed_phy_update_regs() since status.speed = 0 which
makes us hit the "default" label and error out.

Without this change, we would also see potentially inconsistent
speed/duplex parameters for fixed PHYs when the link is DOWN.

CC: netdev@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net>
[florian: add more background to why this is correct and desirable]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/phy/fixed_phy.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -52,6 +52,10 @@ static int fixed_phy_update_regs(struct
 	u16 lpagb = 0;
 	u16 lpa = 0;
 
+	if (!fp->status.link)
+		goto done;
+	bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
+
 	if (fp->status.duplex) {
 		bmcr |= BMCR_FULLDPLX;
 
@@ -96,15 +100,13 @@ static int fixed_phy_update_regs(struct
 		}
 	}
 
-	if (fp->status.link)
-		bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
-
 	if (fp->status.pause)
 		lpa |= LPA_PAUSE_CAP;
 
 	if (fp->status.asym_pause)
 		lpa |= LPA_PAUSE_ASYM;
 
+done:
 	fp->regs[MII_PHYSID1] = 0;
 	fp->regs[MII_PHYSID2] = 0;
 

[PATCH 4.2 28/30] of_mdio: add new DT property managed to specify the PHY management type

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stas Sergeev <stsp@list.ru>

[ Upstream commit 4cba5c2103657d43d0886e4cff8004d95a3d0def in net-next tree,
  will be pushed to Linus very soon. ]

Currently the PHY management type is selected by the MAC driver arbitrary.
The decision is based on the presence of the "fixed-link" node and on a
will of the driver's authors.
This caused a regression recently, when mvneta driver suddenly started
to use the in-band status for auto-negotiation on fixed links.
It appears the auto-negotiation may not work when expected by the MAC driver.
Sebastien Rannou explains:
<< Yes, I confirm that my HW does not generate an in-band status. AFAIK, it's
a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY (with
inband status) is connected to the switch through QSGMII, and in this context
we are on the media side of the PHY. >>
https://lkml.org/lkml/2015/7/10/206

This patch introduces the new string property 'managed' that allows
the user to set the management type explicitly.
The supported values are:
"auto" - default. Uses either MDIO or nothing, depending on the presence
of the fixed-link node
"in-band-status" - use in-band status

Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net>

CC: Rob Herring <robh+dt@kernel.org>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Florian Fainelli <f.fainelli@gmail.com>
CC: Grant Likely <grant.likely@linaro.org>
CC: devicetree@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 Documentation/devicetree/bindings/net/ethernet.txt |    4 ++++
 drivers/of/of_mdio.c                               |   19 +++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

--- a/Documentation/devicetree/bindings/net/ethernet.txt
+++ b/Documentation/devicetree/bindings/net/ethernet.txt
@@ -25,7 +25,11 @@ The following properties are common to t
   flow control thresholds.
 - tx-fifo-depth: the size of the controller's transmit fifo in bytes. This
   is used for components that can have configurable fifo sizes.
+- managed: string, specifies the PHY management type. Supported values are:
+  "auto", "in-band-status". "auto" is the default, it usess MDIO for
+  management if fixed-link is not specified.
 
 Child nodes of the Ethernet controller are typically the individual PHY devices
 connected via the MDIO bus (sometimes the MDIO bus controller is separate).
 They are described in the phy.txt file in this same directory.
+For non-MDIO PHY management see fixed-link.txt.
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -266,7 +266,8 @@ EXPORT_SYMBOL(of_phy_attach);
 bool of_phy_is_fixed_link(struct device_node *np)
 {
 	struct device_node *dn;
-	int len;
+	int len, err;
+	const char *managed;
 
 	/* New binding */
 	dn = of_get_child_by_name(np, "fixed-link");
@@ -275,6 +276,10 @@ bool of_phy_is_fixed_link(struct device_
 		return true;
 	}
 
+	err = of_property_read_string(np, "managed", &managed);
+	if (err == 0 && strcmp(managed, "auto") != 0)
+		return true;
+
 	/* Old binding */
 	if (of_get_property(np, "fixed-link", &len) &&
 	    len == (5 * sizeof(__be32)))
@@ -289,8 +294,18 @@ int of_phy_register_fixed_link(struct de
 	struct fixed_phy_status status = {};
 	struct device_node *fixed_link_node;
 	const __be32 *fixed_link_prop;
-	int len;
+	int len, err;
 	struct phy_device *phy;
+	const char *managed;
+
+	err = of_property_read_string(np, "managed", &managed);
+	if (err == 0) {
+		if (strcmp(managed, "in-band-status") == 0) {
+			/* status is zeroed, namely its .link member */
+			phy = fixed_phy_register(PHY_POLL, &status, np);
+			return IS_ERR(phy) ? PTR_ERR(phy) : 0;
+		}
+	}
 
 	/* New binding */
 	fixed_link_node = of_get_child_by_name(np, "fixed-link");

[PATCH 4.2 29/30] mvneta: use inband status only when explicitly enabled

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stas Sergeev <stsp@list.ru>

[ Upstream commit f8af8e6eb95093d5ce5ebcc52bd1929b0433e172 in net-next tree,
  will be pushed to Linus very soon. ]

The commit 898b2970e2c9 ("mvneta: implement SGMII-based in-band link state
signaling") implemented the link parameters auto-negotiation unconditionally.
Unfortunately it appears that some HW that implements SGMII protocol,
doesn't generate the inband status, so it is not possible to auto-negotiate
anything with such HW.

This patch enables the auto-negotiation only if explicitly requested with
the 'managed' DT property.

This patch fixes the following regression:
https://lkml.org/lkml/2015/7/8/865

Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net>

CC: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
CC: netdev@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/marvell/mvneta.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -3029,8 +3029,8 @@ static int mvneta_probe(struct platform_
 	const char *dt_mac_addr;
 	char hw_mac_addr[ETH_ALEN];
 	const char *mac_from;
+	const char *managed;
 	int phy_mode;
-	int fixed_phy = 0;
 	int err;
 
 	/* Our multiqueue support is not complete, so for now, only
@@ -3064,7 +3064,6 @@ static int mvneta_probe(struct platform_
 			dev_err(&pdev->dev, "cannot register fixed PHY\n");
 			goto err_free_irq;
 		}
-		fixed_phy = 1;
 
 		/* In the case of a fixed PHY, the DT node associated
 		 * to the PHY is the Ethernet MAC DT node.
@@ -3088,8 +3087,10 @@ static int mvneta_probe(struct platform_
 	pp = netdev_priv(dev);
 	pp->phy_node = phy_node;
 	pp->phy_interface = phy_mode;
-	pp->use_inband_status = (phy_mode == PHY_INTERFACE_MODE_SGMII) &&
-				fixed_phy;
+
+	err = of_property_read_string(dn, "managed", &managed);
+	pp->use_inband_status = (err == 0 &&
+				 strcmp(managed, "in-band-status") == 0);
 
 	pp->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(pp->clk)) {