net/usb/r8153_ecm: support ECM mode for RTL8153

diff --git a/drivers/net/usb/Makefile b/drivers/net/usb/Makefile
index 99fd12be2111..99381e6bea78 100644
--- a/drivers/net/usb/Makefile
+++ b/drivers/net/usb/Makefile
@@ -13,7 +13,7 @@  obj-$(CONFIG_USB_LAN78XX)	+= lan78xx.o
 obj-$(CONFIG_USB_NET_AX8817X)	+= asix.o
 asix-y := asix_devices.o asix_common.o ax88172a.o
 obj-$(CONFIG_USB_NET_AX88179_178A)      += ax88179_178a.o
-obj-$(CONFIG_USB_NET_CDCETHER)	+= cdc_ether.o
+obj-$(CONFIG_USB_NET_CDCETHER)	+= cdc_ether.o r8153_ecm.o
 obj-$(CONFIG_USB_NET_CDC_EEM)	+= cdc_eem.o
 obj-$(CONFIG_USB_NET_DM9601)	+= dm9601.o
 obj-$(CONFIG_USB_NET_SR9700)	+= sr9700.o
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index b1770489aca5..1b5d10f1de5f 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -6615,7 +6615,7 @@  static int rtl_fw_init(struct r8152 *tp)
 	return 0;
 }
 
-static u8 rtl_get_version(struct usb_interface *intf)
+u8 rtl8152_get_version(struct usb_interface *intf)
 {
 	struct usb_device *udev = interface_to_usbdev(intf);
 	u32 ocp_data = 0;
@@ -6673,12 +6673,13 @@  static u8 rtl_get_version(struct usb_interface *intf)
 
 	return version;
 }
+EXPORT_SYMBOL_GPL(rtl8152_get_version);
 
 static int rtl8152_probe(struct usb_interface *intf,
 			 const struct usb_device_id *id)
 {
 	struct usb_device *udev = interface_to_usbdev(intf);
-	u8 version = rtl_get_version(intf);
+	u8 version = rtl8152_get_version(intf);
 	struct r8152 *tp;
 	struct net_device *netdev;
 	int ret;
diff --git a/drivers/net/usb/r8153_ecm.c b/drivers/net/usb/r8153_ecm.c
new file mode 100644
index 000000000000..723841525a6a
--- /dev/null
+++ b/drivers/net/usb/r8153_ecm.c
@@ -0,0 +1,174 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/mii.h>
+#include <linux/usb.h>
+#include <linux/usb/cdc.h>
+#include <linux/usb/usbnet.h>
+
+#define RTL8153_CMD		0X05
+#define RTL8153_REQT_READ	0xc0
+#define RTL8153_REQT_WRITE	0x40
+
+#define MCU_TYPE_PLA		0x0100
+#define OCP_BASE		0xe86c
+
+#define BYTE_EN_WORD		0x33
+
+#define REALTEK_VENDOR_ID	0x0bda
+
+#if IS_REACHABLE(CONFIG_USB_RTL8152)
+extern u8 rtl8152_get_version(struct usb_interface *intf);
+#endif
+
+static int pla_read_word(struct usbnet *dev, u16 index)
+{
+	u16 byen = BYTE_EN_WORD;
+	u8 shift = index & 2;
+	__le32 tmp;
+	int ret;
+
+	if (shift)
+		byen <<= shift;
+
+	index &= ~3;
+
+	ret = usbnet_read_cmd(dev, RTL8153_CMD, RTL8153_REQT_READ, index,
+			      MCU_TYPE_PLA | byen, &tmp, sizeof(tmp));
+	if (ret < 0)
+		goto out;
+
+	ret = __le32_to_cpu(tmp);
+	ret >>= (shift * 8);
+	ret &= 0xffff;
+
+out:
+	return ret;
+}
+
+static int pla_write_word(struct usbnet *dev, u16 index, u32 data)
+{
+	u32 mask = 0xffff;
+	u16 byen = BYTE_EN_WORD;
+	u8 shift = index & 2;
+	__le32 tmp;
+	int ret;
+
+	data &= mask;
+
+	if (shift) {
+		byen <<= shift;
+		mask <<= (shift * 8);
+		data <<= (shift * 8);
+	}
+
+	index &= ~3;
+
+	ret = usbnet_read_cmd(dev, RTL8153_CMD, RTL8153_REQT_READ, index,
+			      MCU_TYPE_PLA | byen, &tmp, sizeof(tmp));
+
+	if (ret < 0)
+		goto out;
+
+	data |= __le32_to_cpu(tmp) & ~mask;
+	tmp = __cpu_to_le32(data);
+
+	ret = usbnet_write_cmd(dev, RTL8153_CMD, RTL8153_REQT_WRITE, index,
+			       MCU_TYPE_PLA | byen, &tmp, sizeof(tmp));
+
+out:
+	return ret;
+}
+
+static int r8153_ecm_mdio_read(struct net_device *netdev, int phy_id, int reg)
+{
+	struct usbnet *dev = netdev_priv(netdev);
+	int ret;
+
+	ret = pla_write_word(dev, OCP_BASE, 0xa000);
+	if (ret < 0)
+		goto out;
+
+	ret = pla_read_word(dev, 0xb400 + reg * 2);
+
+out:
+	return ret;
+}
+
+static void r8153_ecm_mdio_write(struct net_device *netdev, int phy_id, int reg, int val)
+{
+	struct usbnet *dev = netdev_priv(netdev);
+	int ret;
+
+	ret = pla_write_word(dev, OCP_BASE, 0xa000);
+	if (ret < 0)
+		return;
+
+	ret = pla_write_word(dev, 0xb400 + reg * 2, val);
+}
+
+static int r8153_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+	int status;
+
+	status = usbnet_cdc_bind(dev, intf);
+	if (status < 0)
+		return status;
+
+	dev->mii.dev = dev->net;
+	dev->mii.mdio_read = r8153_ecm_mdio_read;
+	dev->mii.mdio_write = r8153_ecm_mdio_write;
+	dev->mii.reg_num_mask = 0x1f;
+	dev->mii.supports_gmii = 1;
+
+	return status;
+}
+
+static const struct driver_info r8153_info = {
+	.description =	"RTL8153 ECM Device",
+	.flags =	FLAG_ETHER,
+	.bind =		r8153_bind,
+	.unbind =	usbnet_cdc_unbind,
+	.status =	usbnet_cdc_status,
+	.manage_power =	usbnet_manage_power,
+};
+
+static const struct usb_device_id products[] = {
+{
+	USB_DEVICE_AND_INTERFACE_INFO(REALTEK_VENDOR_ID, 0x8153, USB_CLASS_COMM,
+				      USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE),
+	.driver_info = (unsigned long)&r8153_info,
+},
+
+	{ },		/* END */
+};
+MODULE_DEVICE_TABLE(usb, products);
+
+static int rtl8153_ecm_probe(struct usb_interface *intf,
+			     const struct usb_device_id *id)
+{
+#if IS_REACHABLE(CONFIG_USB_RTL8152)
+	if (rtl8152_get_version(intf))
+		return -ENODEV;
+#endif
+
+	return usbnet_probe(intf, id);
+}
+
+static struct usb_driver r8153_ecm_driver = {
+	.name =		"r8153_ecm",
+	.id_table =	products,
+	.probe =	rtl8153_ecm_probe,
+	.disconnect =	usbnet_disconnect,
+	.suspend =	usbnet_suspend,
+	.resume =	usbnet_resume,
+	.reset_resume =	usbnet_resume,
+	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
+};
+
+module_usb_driver(r8153_ecm_driver);
+
+MODULE_AUTHOR("Hayes Wang");
+MODULE_DESCRIPTION("Realtek USB ECM device");
+MODULE_LICENSE("GPL");