[PATCH v9 1/2] net: mhi: Enable Ethernet interface support

[Vivek Pernamitta <vivek.pernamitta@oss.qualcomm.com>]

Add support to configure a new client as Ethernet type over MHI by
setting "mhi_device_info.ethernet_if = true". Create a new Ethernet
interface named eth%d. This complements existing NET driver support.

Allocate MHI netdevs using NET_NAME_ENUM to reflect kernel-enumerated
naming. This updates the reported name_assign_type for MHI net
interfaces created by this driver, aligning naming semantics across
existing and new devices. No functional or interface naming changes
are introduced

Introduce ETH0 and ETH1 network interfaces required for NETCONF
and S-plane components.

IP_ETH channels represent the Ethernet interface exposed by the
MHI device. The driver creates a corresponding netdev instance,
allowing the host to access and operate the device’s Ethernet
interface.

NETCONF:
Use NETCONF protocol for configuration operations such as fetching,
modifying, and deleting network device configurations.

S-plane:
Support frequency and time synchronization between O-DUs and O-RUs
using Synchronous Ethernet and IEEE 1588. Assume PTP transport over
L2 Ethernet (ITU-T G.8275.1) for full timing support; allow PTP over
UDP/IP (ITU-T G.8275.2) with reduced reliability. as per ORAN spec
O-RAN.WG4.CUS.0-R003-v12.00.

Signed-off-by: Vivek Pernamitta <vivek.pernamitta@oss.qualcomm.com>
---
 drivers/net/mhi_net.c | 65 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 53 insertions(+), 12 deletions(-)

diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
index ae169929a9d8e449b5a427993abf68e8d032fae2..87d8c61fab983005eaea99603d74a557d1483b6e 100644
--- a/drivers/net/mhi_net.c
+++ b/drivers/net/mhi_net.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
  */
 
+#include <linux/etherdevice.h>
 #include <linux/if_arp.h>
 #include <linux/mhi.h>
 #include <linux/mod_devicetable.h>
@@ -42,6 +43,7 @@ struct mhi_net_dev {
 
 struct mhi_device_info {
 	const char *netname;
+	bool ethernet_if;
 };
 
 static int mhi_ndo_open(struct net_device *ndev)
@@ -119,11 +121,29 @@ static void mhi_ndo_get_stats64(struct net_device *ndev,
 	} while (u64_stats_fetch_retry(&mhi_netdev->stats.tx_syncp, start));
 }
 
+static int mhi_mac_address(struct net_device *dev, void *p)
+{
+	if (dev->type == ARPHRD_ETHER)
+		return eth_mac_addr(dev, p);
+
+	return 0;
+}
+
+static int mhi_validate_address(struct net_device *dev)
+{
+	if (dev->type == ARPHRD_ETHER)
+		return eth_validate_addr(dev);
+
+	return 0;
+}
+
 static const struct net_device_ops mhi_netdev_ops = {
 	.ndo_open               = mhi_ndo_open,
 	.ndo_stop               = mhi_ndo_stop,
 	.ndo_start_xmit         = mhi_ndo_xmit,
 	.ndo_get_stats64	= mhi_ndo_get_stats64,
+	.ndo_set_mac_address    = mhi_mac_address,
+	.ndo_validate_addr      = mhi_validate_address,
 };
 
 static void mhi_net_setup(struct net_device *ndev)
@@ -140,6 +160,13 @@ static void mhi_net_setup(struct net_device *ndev)
 	ndev->tx_queue_len = 1000;
 }
 
+static void mhi_ethernet_setup(struct net_device *ndev)
+{
+	ndev->netdev_ops = &mhi_netdev_ops;
+	ether_setup(ndev);
+	ndev->max_mtu = ETH_MAX_MTU;
+}
+
 static struct sk_buff *mhi_net_skb_agg(struct mhi_net_dev *mhi_netdev,
 				       struct sk_buff *skb)
 {
@@ -208,17 +235,20 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
 			skb = mhi_net_skb_agg(mhi_netdev, skb);
 			mhi_netdev->skbagg_head = NULL;
 		}
-
-		switch (skb->data[0] & 0xf0) {
-		case 0x40:
-			skb->protocol = htons(ETH_P_IP);
-			break;
-		case 0x60:
-			skb->protocol = htons(ETH_P_IPV6);
-			break;
-		default:
-			skb->protocol = htons(ETH_P_MAP);
-			break;
+		if (mhi_netdev->ndev->type == ARPHRD_ETHER) {
+			skb->protocol = eth_type_trans(skb, mhi_netdev->ndev);
+		} else {
+			switch (skb->data[0] & 0xf0) {
+			case 0x40:
+				skb->protocol = htons(ETH_P_IP);
+				break;
+			case 0x60:
+				skb->protocol = htons(ETH_P_IPV6);
+				break;
+			default:
+				skb->protocol = htons(ETH_P_MAP);
+				break;
+			}
 		}
 
 		u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
@@ -306,6 +336,9 @@ static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev)
 	struct mhi_net_dev *mhi_netdev;
 	int err;
 
+	if (!!ndev->header_ops)
+		eth_hw_addr_random(ndev);
+
 	mhi_netdev = netdev_priv(ndev);
 
 	dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
@@ -356,7 +389,8 @@ static int mhi_net_probe(struct mhi_device *mhi_dev,
 	int err;
 
 	ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
-			    NET_NAME_PREDICTABLE, mhi_net_setup);
+			    NET_NAME_ENUM, info->ethernet_if ?
+			    mhi_ethernet_setup : mhi_net_setup);
 	if (!ndev)
 		return -ENOMEM;
 
@@ -386,11 +420,18 @@ static const struct mhi_device_info mhi_swip0 = {
 	.netname = "mhi_swip%d",
 };
 
+static const struct mhi_device_info mhi_eth0 = {
+	.netname = "eth%d",
+	.ethernet_if = true,
+};
+
 static const struct mhi_device_id mhi_net_id_table[] = {
 	/* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
 	{ .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
 	/* Software data PATH (to modem CPU) */
 	{ .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
+	{ .chan = "IP_ETH0", .driver_data = (kernel_ulong_t)&mhi_eth0 },
+	{ .chan = "IP_ETH1", .driver_data = (kernel_ulong_t)&mhi_eth0 },
 	{}
 };
 MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);

-- 
2.34.1