Add get/set ethernet address functions and ACPI MAC address pass through functionality to cdc_ncm driver

index 50c05d0f44cb..85093579612f 100644
@@ -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,
 };
 

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71 lines not on this page · raw message

new file mode 100644
index 000000000000..79c7a2d1062e
@@ -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

index 85093579612f..e0152d44f5af 100644
@@ -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,
 };