[PATCH] net: eth-uclass: avoid running start() twice without stop()

[Matthias Schiffer]

Running the start() handler twice without a stop() inbetween completely
breaks communication for some ethernet drivers like fec_mxc.

eth_halt() is called before each eth_init(). Due to the switch to
eth_is_active() in commit 68acb51f442f ("net: Only call halt on a driver
that has been init'ed"), this is not sufficient anymore when netconsole
is active: eth_init_state_only()/eth_halt_state_only() manipulate the
state check that is performed by eth_is_active() without actually
calling into the driver.

The issue can be triggered by starting a network operation (e.g. ping or
tftp) while netconsole is active.

Add an additional "running" flag that reflects the actual state of the
driver and use it to ensure that eth_halt() actually stops the device as
it is supposed to.

Fixes: 68acb51f442f ("net: Only call halt on a driver that has been init'ed")
Signed-off-by: Matthias Schiffer <matthias.schiffer at ew.tq-group.com>
---
 net/eth-uclass.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/eth-uclass.c b/net/eth-uclass.c
index e14695c0f1..7c9278f3a9 100644
--- a/net/eth-uclass.c
+++ b/net/eth-uclass.c
@@ -26,6 +26,7 @@ DECLARE_GLOBAL_DATA_PTR;
  */
 struct eth_device_priv {
 	enum eth_state_t state;
+	bool running;
 };
 
 /**
@@ -293,6 +294,7 @@ int eth_init(void)
 						current->uclass_priv;
 
 					priv->state = ETH_STATE_ACTIVE;
+					priv->running = true;
 					return 0;
 				}
 			} else {
@@ -322,13 +324,16 @@ void eth_halt(void)
 	struct eth_device_priv *priv;
 
 	current = eth_get_dev();
-	if (!current || !eth_is_active(current))
+	if (!current)
 		return;
 
-	eth_get_ops(current)->stop(current);
 	priv = current->uclass_priv;
-	if (priv)
-		priv->state = ETH_STATE_PASSIVE;
+	if (!priv || !priv->running)
+		return;
+
+	eth_get_ops(current)->stop(current);
+	priv->state = ETH_STATE_PASSIVE;
+	priv->running = false;
 }
 
 int eth_is_active(struct udevice *dev)
@@ -537,6 +542,7 @@ static int eth_post_probe(struct udevice *dev)
 #endif
 
 	priv->state = ETH_STATE_INIT;
+	priv->running = false;
 
 	/* Check if the device has a valid MAC address in device tree */
 	if (!eth_dev_get_mac_address(dev, pdata->enetaddr) ||
-- 
2.17.1