netdev - [PATCH] net: sfp: do not probe SFP module before we're attached

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Message-Id: <E1grKog-0004c1-OB@rmk-PC.armlinux.org.uk>
Date:   Wed, 06 Feb 2019 10:52:30 +0000
From:   Russell King <rmk+kernel@...linux.org.uk>
To:     netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH] net: sfp: do not probe SFP module before we're attached

When we probe a SFP module, we expect to be able to call the upstream
device's module_insert() function so that the upstream link can be
configured.  However, when the upstream device is delayed, we currently
may end up probing the module before the upstream device is available,
and lose the module_insert() call.

Avoid this by holding off probing the module until the SFP bus is
properly connected to both the SFP socket driver and the upstream
driver.

Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
---
 drivers/net/phy/sfp-bus.c |  2 ++
 drivers/net/phy/sfp.c     | 30 +++++++++++++++++++++---------
 drivers/net/phy/sfp.h     |  2 ++
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index ad9db652874d..fef701bfad62 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -347,6 +347,7 @@ static int sfp_register_bus(struct sfp_bus *bus)
 				return ret;
 		}
 	}
+	bus->socket_ops->attach(bus->sfp);
 	if (bus->started)
 		bus->socket_ops->start(bus->sfp);
 	bus->netdev->sfp_bus = bus;
@@ -362,6 +363,7 @@ static void sfp_unregister_bus(struct sfp_bus *bus)
 	if (bus->registered) {
 		if (bus->started)
 			bus->socket_ops->stop(bus->sfp);
+		bus->socket_ops->detach(bus->sfp);
 		if (bus->phydev && ops && ops->disconnect_phy)
 			ops->disconnect_phy(bus->upstream);
 	}
diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index fd8bb998ae52..68c8fbf099f8 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -184,6 +184,7 @@ struct sfp {
 
 	struct gpio_desc *gpio[GPIO_MAX];
 
+	bool attached;
 	unsigned int state;
 	struct delayed_work poll;
 	struct delayed_work timeout;
@@ -1475,7 +1476,7 @@ static void sfp_sm_event(struct sfp *sfp, unsigned int event)
 	 */
 	switch (sfp->sm_mod_state) {
 	default:
-		if (event == SFP_E_INSERT) {
+		if (event == SFP_E_INSERT && sfp->attached) {
 			sfp_module_tx_disable(sfp);
 			sfp_sm_ins_next(sfp, SFP_MOD_PROBE, T_PROBE_INIT);
 		}
@@ -1607,6 +1608,19 @@ static void sfp_sm_event(struct sfp *sfp, unsigned int event)
 	mutex_unlock(&sfp->sm_mutex);
 }
 
+static void sfp_attach(struct sfp *sfp)
+{
+	sfp->attached = true;
+	if (sfp->state & SFP_F_PRESENT)
+		sfp_sm_event(sfp, SFP_E_INSERT);
+}
+
+static void sfp_detach(struct sfp *sfp)
+{
+	sfp->attached = false;
+	sfp_sm_event(sfp, SFP_E_REMOVE);
+}
+
 static void sfp_start(struct sfp *sfp)
 {
 	sfp_sm_event(sfp, SFP_E_DEV_UP);
@@ -1667,6 +1681,8 @@ static int sfp_module_eeprom(struct sfp *sfp, struct ethtool_eeprom *ee,
 }
 
 static const struct sfp_socket_ops sfp_module_ops = {
+	.attach = sfp_attach,
+	.detach = sfp_detach,
 	.start = sfp_start,
 	.stop = sfp_stop,
 	.module_info = sfp_module_info,
@@ -1834,10 +1850,6 @@ static int sfp_probe(struct platform_device *pdev)
 	dev_info(sfp->dev, "Host maximum power %u.%uW\n",
 		 sfp->max_power_mW / 1000, (sfp->max_power_mW / 100) % 10);
 
-	sfp->sfp_bus = sfp_register_socket(sfp->dev, sfp, &sfp_module_ops);
-	if (!sfp->sfp_bus)
-		return -ENOMEM;
-
 	/* Get the initial state, and always signal TX disable,
 	 * since the network interface will not be up.
 	 */
@@ -1848,10 +1860,6 @@ static int sfp_probe(struct platform_device *pdev)
 		sfp->state |= SFP_F_RATE_SELECT;
 	sfp_set_state(sfp, sfp->state);
 	sfp_module_tx_disable(sfp);
-	rtnl_lock();
-	if (sfp->state & SFP_F_PRESENT)
-		sfp_sm_event(sfp, SFP_E_INSERT);
-	rtnl_unlock();
 
 	for (i = 0; i < GPIO_MAX; i++) {
 		if (gpio_flags[i] != GPIOD_IN || !sfp->gpio[i])
@@ -1884,6 +1892,10 @@ static int sfp_probe(struct platform_device *pdev)
 		dev_warn(sfp->dev,
 			 "No tx_disable pin: SFP modules will always be emitting.\n");
 
+	sfp->sfp_bus = sfp_register_socket(sfp->dev, sfp, &sfp_module_ops);
+	if (!sfp->sfp_bus)
+		return -ENOMEM;
+
 	return 0;
 }
 
diff --git a/drivers/net/phy/sfp.h b/drivers/net/phy/sfp.h
index 31b0acf337e2..64f54b0bbd8c 100644
--- a/drivers/net/phy/sfp.h
+++ b/drivers/net/phy/sfp.h
@@ -7,6 +7,8 @@
 struct sfp;
 
 struct sfp_socket_ops {
+	void (*attach)(struct sfp *sfp);
+	void (*detach)(struct sfp *sfp);
 	void (*start)(struct sfp *sfp);
 	void (*stop)(struct sfp *sfp);
 	int (*module_info)(struct sfp *sfp, struct ethtool_modinfo *modinfo);
-- 
2.7.4