[PATCH v3 0/3] Add get/set ethernet address functions and ACPI MAC address pass through functionality to cdc_ncm driver

[PATCH v3 0/3] Add get/set ethernet address functions and ACPI MAC address pass through functionality to cdc_ncm driver

[Charles Hyde]

In recent testing of a Dell Universal Dock D6000, I found that MAC
address pass through is not supported in the Linux drivers.  However,
this same device is supported in Windows 10 (Pro) on my personal
computer, in as much as I was able to tell Windows to assign a new MAC
address of my choosing, and I saw through wireshark the new MAC address
was pushed out to the device.  Afterward, Windows reported a new IP
address and I was able to view web pages.

This series of patches give support to cdc_ncm USB based Ethernet
controllers for programming a MAC address to the device, and also to
retrieve the device's MAC address.  This patch series further adds ACPI
MAC address pass through support specifically for the cdc_ncm driver, and
generally for any other driver that may need or want it, in furtherance of
Dell's enterprise IT policy efforts.  It was this latter that I initially
found lacking when testing a D6000 with a Dell laptop, and then I found
ifconfig was unable to set a MAC address into the device.  These patches
bring a similar level of functionality to cdc_ncm driver as is available
with the Realtek r8152 driver, and is available with Windows.

The cdc_ncm driver limits the ACPI MAC address pass through support to
only the Dell Universal Dock D6000, so no other cdc_ncm device will be
impacted.

Today's v3 patch series includes a function named get_ethernet_addr()
which replaces two instances where the same code snippet was located in
teh previous patch series.  I also created a post reset function to set
the MAC address, if there exists an ACPI MAC address pass through (MAPT)
method.  Oliver Neukum had requested a post reset function for this
purpose.


Charles Hyde (3):
  net: cdc_ncm: add get/set ethernet address functions
  ACPI: move ACPI functionality out of r8152 driver
  net: cdc_ncm: Add ACPI MAC address pass through functionality

 drivers/acpi/Makefile            |   1 +
 drivers/acpi/acpi_mac_passthru.c |  63 +++++++++++++
 drivers/net/usb/cdc_ncm.c        | 148 ++++++++++++++++++++++++++++---
 drivers/net/usb/r8152.c          |  44 +--------
 include/acpi/acpi_mac_passthru.h |  27 ++++++
 5 files changed, 232 insertions(+), 51 deletions(-)
 create mode 100644 drivers/acpi/acpi_mac_passthru.c
 create mode 100644 include/acpi/acpi_mac_passthru.h

-- 
2.20.1

[PATCH v3 1/3] net: cdc_ncm: add get/set ethernet address functions

[Charles Hyde]

This patch adds support for pushing a MAC address out to USB based
ethernet controllers driven by cdc_ncm.  With this change, ifconfig can
now set the device's MAC address.  For example, the Dell Universal Dock
D6000 is driven by cdc_ncm.  The D6000 can now have its MAC address set
by ifconfig, as it can be done in Windows.  This was tested with a D6000
using ifconfig on an x86 based chromebook, where iproute2 is not
available.

Signed-off-by: Charles Hyde <charles.hyde@dellteam.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Cc: chip.programmer@gmail.com
Cc: Oliver Neukum <oliver@neukum.org>
Cc: linux-usb@vger.kernel.org
---
 drivers/net/usb/cdc_ncm.c | 74 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 50c05d0f44cb..85093579612f 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -750,6 +750,78 @@ int cdc_ncm_change_mtu(struct net_device *net, int new_mtu)
 }
 EXPORT_SYMBOL_GPL(cdc_ncm_change_mtu);
 
+/* Provide method to get MAC address from the USB device's ethernet controller.
+ * If the device supports CDC_GET_ADDRESS, we should receive just six bytes.
+ * Otherwise, use the prior method by asking for the descriptor.
+ */
+static int cdc_ncm_get_ethernet_address(struct usbnet *dev,
+					struct cdc_ncm_ctx *ctx)
+{
+	int ret;
+	char *buf;
+
+	buf = kmalloc(ETH_ALEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = usbnet_read_cmd(dev, USB_CDC_GET_NET_ADDRESS,
+			      USB_DIR_IN | USB_TYPE_CLASS
+			      | USB_RECIP_INTERFACE, 0,
+			      USB_REQ_SET_ADDRESS, buf, ETH_ALEN);
+	if (ret == ETH_ALEN) {
+		memcpy(dev->net->dev_addr, buf, ETH_ALEN);
+		ret = 0;	/* success */
+	} else {
+		ret = usbnet_get_ethernet_addr(dev,
+					       ctx->ether_desc->iMACAddress);
+	}
+	kfree(buf);
+	return ret;
+}
+
+/* Provide method to push MAC address to the USB device's ethernet controller.
+ * If the device does not support CDC_SET_ADDRESS, there is no harm and we
+ * proceed as before.
+ */
+static int cdc_ncm_set_ethernet_address(struct usbnet *dev,
+					struct sockaddr *addr)
+{
+	int ret;
+	char *buf;
+
+	buf = kmalloc(ETH_ALEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	memcpy(buf, addr->sa_data, ETH_ALEN);
+	ret = usbnet_write_cmd(dev, USB_CDC_SET_NET_ADDRESS,
+			       USB_DIR_OUT | USB_TYPE_CLASS
+			       | USB_RECIP_INTERFACE, 0,
+			       USB_REQ_SET_ADDRESS, buf, ETH_ALEN);
+	if (ret == ETH_ALEN)
+		ret = 0;	/* success */
+	else if (ret < 0)
+		dev_dbg(&dev->udev->dev, "bad MAC address put, %d\n", ret);
+
+	kfree(buf);
+	return ret;
+}
+
+/* Provide method to push MAC address to the USB device's ethernet controller.
+ */
+int cdc_ncm_set_mac_addr(struct net_device *net, void *p)
+{
+	struct usbnet *dev = netdev_priv(net);
+
+	/* Try to push the MAC address out to the device.  Ignore any errors,
+	 * to be compatible with prior versions of this source.
+	 */
+	cdc_ncm_set_ethernet_address(dev, (struct sockaddr *)p);
+
+	return eth_mac_addr(net, p);
+}
+EXPORT_SYMBOL_GPL(cdc_ncm_set_mac_addr);
+
 static const struct net_device_ops cdc_ncm_netdev_ops = {
 	.ndo_open	     = usbnet_open,
 	.ndo_stop	     = usbnet_stop,
@@ -757,7 +829,7 @@ static const struct net_device_ops cdc_ncm_netdev_ops = {
 	.ndo_tx_timeout	     = usbnet_tx_timeout,
 	.ndo_get_stats64     = usbnet_get_stats64,
 	.ndo_change_mtu	     = cdc_ncm_change_mtu,
-	.ndo_set_mac_address = eth_mac_addr,
+	.ndo_set_mac_address = cdc_ncm_set_mac_addr,
 	.ndo_validate_addr   = eth_validate_addr,
 };
 
-- 
2.20.1

[PATCH v3 2/3] ACPI: move ACPI functionality out of r8152 driver

[Charles Hyde]

This change moves ACPI functionality out of the Realtek r8152 driver to
its own source and header file, making it available to other drivers as
needed now and into the future.  At the time this ACPI snippet was
introduced in 2016, only the Realtek driver made use of it in support of
Dell's enterprise IT policy efforts.  There comes now a need for this
same support in a different driver, also in support of Dell's enterprise
IT policy efforts.

Signed-off-by: Charles Hyde <charles.hyde@dellteam.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Cc: chip.programmer@gmail.com
Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
---
 drivers/acpi/Makefile            |  1 +
 drivers/acpi/acpi_mac_passthru.c | 63 ++++++++++++++++++++++++++++++++
 drivers/net/usb/r8152.c          | 44 ++--------------------
 include/acpi/acpi_mac_passthru.h | 27 ++++++++++++++
 4 files changed, 95 insertions(+), 40 deletions(-)
 create mode 100644 drivers/acpi/acpi_mac_passthru.c
 create mode 100644 include/acpi/acpi_mac_passthru.h

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 5d361e4e3405..6bc2748f0e00 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -66,6 +66,7 @@ acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
 acpi-$(CONFIG_ACPI_ADXL)	+= acpi_adxl.o
 
 # These are (potentially) separate modules
+acpi-y				+= acpi_mac_passthru.o
 
 # IPMI may be used by other drivers, so it has to initialise before them
 obj-$(CONFIG_ACPI_IPMI)		+= acpi_ipmi.o
diff --git a/drivers/acpi/acpi_mac_passthru.c b/drivers/acpi/acpi_mac_passthru.c
new file mode 100644
index 000000000000..37d7e2388c0b
--- /dev/null
+++ b/drivers/acpi/acpi_mac_passthru.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * acpi_mac_passthru.c - ACPI MAC address pass through driver
+ *
+ *  Copyright (c) 2019 Dell Technology. All rights reserved.
+ *
+ * Search for MAC Address Pass Through information, and return the MAC address
+ * found.  This is set through enterprise policy settings, and expected to be
+ * read by ethernet drivers that have software programmable MAC addresses.
+ * Failure to find the needed information results in -ENODEV.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_mac_passthru.h>
+#include <linux/etherdevice.h>
+
+ACPI_MODULE_NAME("mapt");
+
+MODULE_AUTHOR("Charles Hyde");
+MODULE_DESCRIPTION("ACPI MAPT Driver");
+MODULE_LICENSE("GPL");
+
+int get_acpi_mac_passthru(char *macAddress)
+{
+	acpi_status status;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	int ret = -EINVAL;
+	unsigned char buf[6];
+
+	/* returns _AUXMAC_#AABBCCDDEEFF# */
+	status = acpi_evaluate_object(NULL, "\\_SB.AMAC", NULL, &buffer);
+	obj = (union acpi_object *)buffer.pointer;
+	if (!ACPI_SUCCESS(status))
+		return -ENODEV;
+	if (obj->type != ACPI_TYPE_BUFFER || obj->string.length != 0x17) {
+		acpi_info("Invalid buffer for pass-thru MAC addr: (%d, %d)\n",
+			  obj->type, obj->string.length);
+		goto amacout;
+	}
+	if (strncmp(obj->string.pointer, "_AUXMAC_#", 9) != 0 ||
+	    strncmp(obj->string.pointer + 0x15, "#", 1) != 0) {
+		acpi_info("Invalid header when reading pass-thru MAC addr\n");
+		goto amacout;
+	}
+	ret = hex2bin(buf, obj->string.pointer + 9, 6);
+	if (!(ret == 0 && is_valid_ether_addr(buf))) {
+		acpi_info("Invalid MAC for pass-thru MAC addr: %d, %pM\n",
+			  ret, buf);
+		ret = -EINVAL;
+		goto amacout;
+	}
+	memcpy(macAddress, buf, 6);
+	acpi_info("Pass-thru MAC addr %pM\n", macAddress);
+
+amacout:
+	kfree(obj);
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(get_acpi_mac_passthru);
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 04137ac373b0..6b9de6ae6524 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -23,6 +23,7 @@
 #include <linux/usb/cdc.h>
 #include <linux/suspend.h>
 #include <linux/acpi.h>
+#include <acpi/acpi_mac_passthru.h>
 
 /* Information for net-next */
 #define NETNEXT_VERSION		"09"
@@ -1178,12 +1179,7 @@ static int rtl8152_set_mac_address(struct net_device *netdev, void *p)
  */
 static int vendor_mac_passthru_addr_read(struct r8152 *tp, struct sockaddr *sa)
 {
-	acpi_status status;
-	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *obj;
-	int ret = -EINVAL;
 	u32 ocp_data;
-	unsigned char buf[6];
 
 	/* test for -AD variant of RTL8153 */
 	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_MISC_0);
@@ -1204,39 +1200,7 @@ static int vendor_mac_passthru_addr_read(struct r8152 *tp, struct sockaddr *sa)
 			return -ENODEV;
 		}
 	}
-
-	/* returns _AUXMAC_#AABBCCDDEEFF# */
-	status = acpi_evaluate_object(NULL, "\\_SB.AMAC", NULL, &buffer);
-	obj = (union acpi_object *)buffer.pointer;
-	if (!ACPI_SUCCESS(status))
-		return -ENODEV;
-	if (obj->type != ACPI_TYPE_BUFFER || obj->string.length != 0x17) {
-		netif_warn(tp, probe, tp->netdev,
-			   "Invalid buffer for pass-thru MAC addr: (%d, %d)\n",
-			   obj->type, obj->string.length);
-		goto amacout;
-	}
-	if (strncmp(obj->string.pointer, "_AUXMAC_#", 9) != 0 ||
-	    strncmp(obj->string.pointer + 0x15, "#", 1) != 0) {
-		netif_warn(tp, probe, tp->netdev,
-			   "Invalid header when reading pass-thru MAC addr\n");
-		goto amacout;
-	}
-	ret = hex2bin(buf, obj->string.pointer + 9, 6);
-	if (!(ret == 0 && is_valid_ether_addr(buf))) {
-		netif_warn(tp, probe, tp->netdev,
-			   "Invalid MAC for pass-thru MAC addr: %d, %pM\n",
-			   ret, buf);
-		ret = -EINVAL;
-		goto amacout;
-	}
-	memcpy(sa->sa_data, buf, 6);
-	netif_info(tp, probe, tp->netdev,
-		   "Using pass-thru MAC addr %pM\n", sa->sa_data);
-
-amacout:
-	kfree(obj);
-	return ret;
+	return get_acpi_mac_passthru(sa->sa_data);
 }
 
 static int determine_ethernet_addr(struct r8152 *tp, struct sockaddr *sa)
@@ -4311,10 +4275,10 @@ static int rtl8152_post_reset(struct usb_interface *intf)
 	if (!tp)
 		return 0;
 
-	/* reset the MAC adddress in case of policy change */
+	/* reset the MAC address in case of policy change */
 	if (determine_ethernet_addr(tp, &sa) >= 0) {
 		rtnl_lock();
-		dev_set_mac_address (tp->netdev, &sa, NULL);
+		dev_set_mac_address(tp->netdev, &sa, NULL);
 		rtnl_unlock();
 	}
 
diff --git a/include/acpi/acpi_mac_passthru.h b/include/acpi/acpi_mac_passthru.h
new file mode 100644
index 000000000000..79c7a2d1062e
--- /dev/null
+++ b/include/acpi/acpi_mac_passthru.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * acpi_mac_passthru.h - ACPI MAC address pass through driver
+ *
+ *  Copyright (c) 2019 Dell Technology. All rights reserved.
+ *
+ * Search for MAC Address Pass Through information, and return the MAC address
+ * found.  This is set through enterprise policy settings, and expected to be
+ * read by ethernet drivers that have software programmable MAC addresses.
+ * Failure to find the needed information results in -ENODEV.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+
+#ifdef CONFIG_ACPI
+
+int get_acpi_mac_passthru(char *macAddress);
+
+#else
+
+static inline int get_acpi_mac_passthru(char *macAddress)
+{
+	return -ENODEV;
+}
+
+#endif
-- 
2.20.1

[PATCH v3 3/3] net: cdc_ncm: Add ACPI MAC address pass through functionality

[Charles Hyde]

This change adds support to cdc_ncm for ACPI MAC address pass through
functionality that also exists in the Realtek r8152 driver.  This is in
support of Dell's Universal Dock D6000, to give it the same feature
capability as is currently available in Windows and advertized on Dell's
product web site.

Today's v3 patch series includes a function named get_ethernet_addr()
which replaces two instances where the same code snippet was located in
teh previous patch series.  I also created a post reset function to set
the MAC address, if there exists an ACPI MAC address pass through (MAPT)
method.  Oliver Neukum had requested a post reset function for this
purpose.

Signed-off-by: Charles Hyde <charles.hyde@dellteam.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Cc: chip.programmer@gmail.com
Cc: Oliver Neukum <oliver@neukum.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
---
 drivers/net/usb/cdc_ncm.c | 74 +++++++++++++++++++++++++++++++++------
 1 file changed, 64 insertions(+), 10 deletions(-)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 85093579612f..e0152d44f5af 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -52,6 +52,7 @@
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/cdc_ncm.h>
+#include <acpi/acpi_mac_passthru.h>
 
 #if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
 static bool prefer_mbim = true;
@@ -833,6 +834,45 @@ static const struct net_device_ops cdc_ncm_netdev_ops = {
 	.ndo_validate_addr   = eth_validate_addr,
 };
 
+static int get_ethernet_addr(struct usb_interface *intf)
+{
+	struct sockaddr sa;
+	struct usbnet *dev = usb_get_intfdata(intf);
+	struct cdc_ncm_ctx *ctx;
+	int ret = 0;
+
+	if (!dev)
+		return 0;
+
+	ctx = (struct cdc_ncm_ctx *)dev->data[0];
+	if (!ctx->ether_desc)
+		return 0;
+
+	ret = cdc_ncm_get_ethernet_address(dev, ctx);
+	if (ret) {
+		dev_dbg(&intf->dev, "failed to get mac address\n");
+		return ret;
+	}
+
+	/* Check for a Dell Universal Dock D6000 before checking if ACPI
+	 * supports MAC address pass through.
+	 */
+	if (strstr(dev->udev->product, "D6000")) {
+		sa.sa_family = dev->net->type;
+		if (get_acpi_mac_passthru(sa.sa_data)) {
+			if (!memcmp(dev->net->dev_addr, sa.sa_data,
+				    ETH_ALEN)) {
+				if (!cdc_ncm_set_ethernet_address(dev, &sa))
+					memcpy(dev->net->dev_addr, sa.sa_data,
+					       ETH_ALEN);
+			}
+		}
+	}
+	dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
+
+	return 0;
+}
+
 int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags)
 {
 	struct cdc_ncm_ctx *ctx;
@@ -983,14 +1023,8 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
 	usb_set_intfdata(ctx->data, dev);
 	usb_set_intfdata(ctx->control, dev);
 
-	if (ctx->ether_desc) {
-		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
-		if (temp) {
-			dev_dbg(&intf->dev, "failed to get mac address\n");
-			goto error2;
-		}
-		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
-	}
+	if (get_ethernet_addr(intf))
+		goto error2;
 
 	/* finish setting up the device specific data */
 	cdc_ncm_setup(dev);
@@ -1716,6 +1750,25 @@ static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
 	}
 }
 
+static int cdc_ncm_resume(struct usb_interface *intf)
+{
+	int ret;
+
+	ret = usbnet_resume(intf);
+	if (ret == 0)
+		get_ethernet_addr(intf);
+
+	return ret;
+}
+
+static int cdc_ncm_post_reset(struct usb_interface *intf)
+{
+	/* reset the MAC address in case of policy change */
+	get_ethernet_addr(intf);
+
+	return 0;
+}
+
 static const struct driver_info cdc_ncm_info = {
 	.description = "CDC NCM",
 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
@@ -1848,8 +1901,9 @@ static struct usb_driver cdc_ncm_driver = {
 	.probe = usbnet_probe,
 	.disconnect = usbnet_disconnect,
 	.suspend = usbnet_suspend,
-	.resume = usbnet_resume,
-	.reset_resume =	usbnet_resume,
+	.resume = cdc_ncm_resume,
+	.reset_resume =	cdc_ncm_resume,
+	.post_reset = cdc_ncm_post_reset,
 	.supports_autosuspend = 1,
 	.disable_hub_initiated_lpm = 1,
 };
-- 
2.20.1

Re: [PATCH v3 3/3] net: cdc_ncm: Add ACPI MAC address pass through functionality

[Greg KH]

On Thu, Sep 05, 2019 at 08:51:15PM -0500, Charles Hyde wrote:
> This change adds support to cdc_ncm for ACPI MAC address pass through
> functionality that also exists in the Realtek r8152 driver.  This is in
> support of Dell's Universal Dock D6000, to give it the same feature
> capability as is currently available in Windows and advertized on Dell's
> product web site.
> 
> Today's v3 patch series includes a function named get_ethernet_addr()
> which replaces two instances where the same code snippet was located in
> teh previous patch series.  I also created a post reset function to set
> the MAC address, if there exists an ACPI MAC address pass through (MAPT)
> method.  Oliver Neukum had requested a post reset function for this
> purpose.
> 
> Signed-off-by: Charles Hyde <charles.hyde@dellteam.com>
> Cc: Mario Limonciello <mario.limonciello@dell.com>
> Cc: chip.programmer@gmail.com
> Cc: Oliver Neukum <oliver@neukum.org>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>
> Cc: linux-usb@vger.kernel.org
> Cc: linux-acpi@vger.kernel.org
> ---
>  drivers/net/usb/cdc_ncm.c | 74 +++++++++++++++++++++++++++++++++------
>  1 file changed, 64 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
> index 85093579612f..e0152d44f5af 100644
> --- a/drivers/net/usb/cdc_ncm.c
> +++ b/drivers/net/usb/cdc_ncm.c
> @@ -52,6 +52,7 @@
>  #include <linux/usb/usbnet.h>
>  #include <linux/usb/cdc.h>
>  #include <linux/usb/cdc_ncm.h>
> +#include <acpi/acpi_mac_passthru.h>
>  
>  #if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
>  static bool prefer_mbim = true;
> @@ -833,6 +834,45 @@ static const struct net_device_ops cdc_ncm_netdev_ops = {
>  	.ndo_validate_addr   = eth_validate_addr,
>  };
>  
> +static int get_ethernet_addr(struct usb_interface *intf)
> +{
> +	struct sockaddr sa;
> +	struct usbnet *dev = usb_get_intfdata(intf);
> +	struct cdc_ncm_ctx *ctx;
> +	int ret = 0;
> +
> +	if (!dev)
> +		return 0;
> +
> +	ctx = (struct cdc_ncm_ctx *)dev->data[0];
> +	if (!ctx->ether_desc)
> +		return 0;
> +
> +	ret = cdc_ncm_get_ethernet_address(dev, ctx);
> +	if (ret) {
> +		dev_dbg(&intf->dev, "failed to get mac address\n");
> +		return ret;
> +	}
> +
> +	/* Check for a Dell Universal Dock D6000 before checking if ACPI
> +	 * supports MAC address pass through.
> +	 */
> +	if (strstr(dev->udev->product, "D6000")) {

As other people have pointed out, that's funny.

No, this is explicitly what the USB vendor/product ids are for, don't
try to make up something that will be guaranteed to not work
correctly...

> +		sa.sa_family = dev->net->type;
> +		if (get_acpi_mac_passthru(sa.sa_data)) {
> +			if (!memcmp(dev->net->dev_addr, sa.sa_data,
> +				    ETH_ALEN)) {
> +				if (!cdc_ncm_set_ethernet_address(dev, &sa))
> +					memcpy(dev->net->dev_addr, sa.sa_data,
> +					       ETH_ALEN);
> +			}
> +		}
> +	}
> +	dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);

If a driver is working properly, it should not spit out any kernel log
messages.  Make this dev_dbg() if you need it for your own debugging
logic.

thanks,

greg k-h