[PATCH v4 4/4] usb: gadget: ether: Handle gadget driver registration in probe and remove

[Marek Vasut <marex@denx.de>]

Move the ethernet gadget driver registration and removal from ethernet
bind and unbind callbacks into driver DM probe and remove callbacks.
This way, when the driver is bound, which is triggered deliberately
using 'bind' command, the USB ethernet gadget driver is instantiated
and bound to the matching UDC. In reverse, when the driver is unbound,
which is again triggered deliberately using 'unbind' command, the USB
ethernet gadget driver instance is removed.

Effectively, this now behaves like running either 'ums' or 'dfu' or
any other commands utilizing USB gadget functionality.

This also drops use of usb_gadget_release() and moves the use of
usb_gadget_initialize() into usb_ether_init() used only by legacy
platforms that do not use 'bind' command properly yet. Those have
no place in drivers.

Signed-off-by: Marek Vasut <marex@denx.de>
---
NOTE: This must be thoroughly tested.
---
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Lukasz Majewski <lukma@denx.de>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Simon Glass <sjg@chromium.org>
---
V2: Fix up return value handling in probe
V3: Reinstate usb_gadget_initialize() in usb_ether_init() to retain
    this obscure workaround for legacy platforms that fail to use
    bind command
V4: Call usb_gadget_release() in unbind callback to further help
    legacy platforms
---
 drivers/usb/gadget/ether.c | 97 ++++++++++++++++++++------------------
 1 file changed, 52 insertions(+), 45 deletions(-)

diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index 2040b5b5081..5ff06d3814b 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -2281,49 +2281,8 @@ static int usb_eth_start(struct udevice *udev)
 	struct eth_dev *dev = &priv->ethdev;
 	struct usb_gadget *gadget;
 	unsigned long ts;
-	int ret;
 	unsigned long timeout = USB_CONNECT_TIMEOUT;
 
-	ret = usb_gadget_initialize(0);
-	if (ret)
-		return ret;
-
-	/* Configure default mac-addresses for the USB ethernet device */
-#ifdef CONFIG_USBNET_DEV_ADDR
-	strlcpy(dev_addr, CONFIG_USBNET_DEV_ADDR, sizeof(dev_addr));
-#endif
-#ifdef CONFIG_USBNET_HOST_ADDR
-	strlcpy(host_addr, CONFIG_USBNET_HOST_ADDR, sizeof(host_addr));
-#endif
-	/* Check if the user overruled the MAC addresses */
-	if (env_get("usbnet_devaddr"))
-		strlcpy(dev_addr, env_get("usbnet_devaddr"),
-			sizeof(dev_addr));
-
-	if (env_get("usbnet_hostaddr"))
-		strlcpy(host_addr, env_get("usbnet_hostaddr"),
-			sizeof(host_addr));
-
-	if (!is_eth_addr_valid(dev_addr)) {
-		pr_err("Need valid 'usbnet_devaddr' to be set");
-		goto fail;
-	}
-	if (!is_eth_addr_valid(host_addr)) {
-		pr_err("Need valid 'usbnet_hostaddr' to be set");
-		goto fail;
-	}
-
-	priv->eth_driver.speed		= DEVSPEED;
-	priv->eth_driver.bind		= eth_bind;
-	priv->eth_driver.unbind		= eth_unbind;
-	priv->eth_driver.setup		= eth_setup;
-	priv->eth_driver.reset		= eth_disconnect;
-	priv->eth_driver.disconnect	= eth_disconnect;
-	priv->eth_driver.suspend	= eth_suspend;
-	priv->eth_driver.resume		= eth_resume;
-	if (usb_gadget_register_driver(&priv->eth_driver) < 0)
-		goto fail;
-
 	dev->network_started = 0;
 
 	packet_received = 0;
@@ -2450,9 +2409,6 @@ static void usb_eth_stop(struct udevice *udev)
 		usb_gadget_handle_interrupts(0);
 		dev->network_started = 0;
 	}
-
-	usb_gadget_unregister_driver(&priv->eth_driver);
-	usb_gadget_release(0);
 }
 
 static int usb_eth_recv(struct udevice *dev, int flags, uchar **packetp)
@@ -2511,7 +2467,7 @@ int usb_ether_init(void)
 		return ret;
 	}
 
-	return 0;
+	return usb_gadget_initialize(0);
 }
 
 static int usb_eth_probe(struct udevice *dev)
@@ -2525,6 +2481,55 @@ static int usb_eth_probe(struct udevice *dev)
 	get_ether_addr(CONFIG_USBNET_DEV_ADDR, pdata->enetaddr);
 	eth_env_set_enetaddr("usbnet_devaddr", pdata->enetaddr);
 
+	/* Configure default mac-addresses for the USB ethernet device */
+#ifdef CONFIG_USBNET_DEV_ADDR
+	strlcpy(dev_addr, CONFIG_USBNET_DEV_ADDR, sizeof(dev_addr));
+#endif
+#ifdef CONFIG_USBNET_HOST_ADDR
+	strlcpy(host_addr, CONFIG_USBNET_HOST_ADDR, sizeof(host_addr));
+#endif
+	/* Check if the user overruled the MAC addresses */
+	if (env_get("usbnet_devaddr"))
+		strlcpy(dev_addr, env_get("usbnet_devaddr"),
+			sizeof(dev_addr));
+
+	if (env_get("usbnet_hostaddr"))
+		strlcpy(host_addr, env_get("usbnet_hostaddr"),
+			sizeof(host_addr));
+
+	if (!is_eth_addr_valid(dev_addr)) {
+		pr_err("Need valid 'usbnet_devaddr' to be set");
+		return -EINVAL;
+	}
+	if (!is_eth_addr_valid(host_addr)) {
+		pr_err("Need valid 'usbnet_hostaddr' to be set");
+		return -EINVAL;
+	}
+
+	priv->eth_driver.speed		= DEVSPEED;
+	priv->eth_driver.bind		= eth_bind;
+	priv->eth_driver.unbind		= eth_unbind;
+	priv->eth_driver.setup		= eth_setup;
+	priv->eth_driver.reset		= eth_disconnect;
+	priv->eth_driver.disconnect	= eth_disconnect;
+	priv->eth_driver.suspend	= eth_suspend;
+	priv->eth_driver.resume		= eth_resume;
+	return usb_gadget_register_driver(&priv->eth_driver);
+}
+
+static int usb_eth_remove(struct udevice *dev)
+{
+	struct ether_priv *priv = dev_get_priv(dev);
+
+	usb_gadget_unregister_driver(&priv->eth_driver);
+
+	return 0;
+}
+
+static int usb_eth_unbind(struct udevice *dev)
+{
+	usb_gadget_release(0);
+
 	return 0;
 }
 
@@ -2532,6 +2537,8 @@ U_BOOT_DRIVER(eth_usb) = {
 	.name	= "usb_ether",
 	.id	= UCLASS_ETH,
 	.probe	= usb_eth_probe,
+	.remove	= usb_eth_remove,
+	.unbind	= usb_eth_unbind,
 	.ops	= &usb_eth_ops,
 	.priv_auto	= sizeof(struct ether_priv),
 	.plat_auto	= sizeof(struct eth_pdata),
-- 
2.40.1