[PATCH v6 1/2] net: mhi: Enable Ethernet interface support

From: Vivek Pernamitta <[email protected]>

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.

Introduce IP_SW1, ETH0, and ETH1 network interfaces required for
M-plane, NETCONF, and S-plane components.

M-plane:
Implement DU M-Plane software for non-real-time O-RAN management
between O-DU and O-RU using NETCONF/YANG and O-RAN WG4 M-Plane YANG
models. Provide capability exchange, configuration management,
performance monitoring, and fault management per O-RAN.WG4.TS.MP.0-
R004-v18.00.

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 <[email protected]>
---
 drivers/net/mhi_net.c | 75 ++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 62 insertions(+), 13 deletions(-)

diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
index ae169929a9d8e449b5a427993abf68e8d032fae2..d0713e1eb7b024667f8f3f00ed3cf38d91a75708 100644
--- a/drivers/net/mhi_net.c
+++ b/drivers/net/mhi_net.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2020 Linaro Ltd <[email protected]>
  */
 
+#include <linux/etherdevice.h>
 #include <linux/if_arp.h>
 #include <linux/mhi.h>
 #include <linux/mod_devicetable.h>
@@ -38,10 +39,12 @@ struct mhi_net_dev {
 	u32 rx_queue_sz;
 	int msg_enable;
 	unsigned int mru;
+	bool ethernet_if;
 };
 
 struct mhi_device_info {
 	const char *netname;
+	bool ethernet_if;
 };
 
 static int mhi_ndo_open(struct net_device *ndev)
@@ -119,11 +122,29 @@ 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 +161,13 @@ 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)
 {
@@ -209,16 +237,22 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
 			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->ethernet_if) {
+			skb_copy_to_linear_data(skb, skb->data,
+						mhi_res->bytes_xferd);
+			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);
@@ -301,11 +335,14 @@ static void mhi_net_rx_refill_work(struct work_struct *work)
 		schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
 }
 
-static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev)
+static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev, bool eth_dev)
 {
 	struct mhi_net_dev *mhi_netdev;
 	int err;
 
+	if (eth_dev)
+		eth_hw_addr_random(ndev);
+
 	mhi_netdev = netdev_priv(ndev);
 
 	dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
@@ -313,6 +350,7 @@ static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev)
 	mhi_netdev->mdev = mhi_dev;
 	mhi_netdev->skbagg_head = NULL;
 	mhi_netdev->mru = mhi_dev->mhi_cntrl->mru;
+	mhi_netdev->ethernet_if = eth_dev;
 
 	INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
 	u64_stats_init(&mhi_netdev->stats.rx_syncp);
@@ -356,13 +394,14 @@ 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_PREDICTABLE, info->ethernet_if ?
+			    mhi_ethernet_setup : mhi_net_setup);
 	if (!ndev)
 		return -ENOMEM;
 
 	SET_NETDEV_DEV(ndev, &mhi_dev->dev);
 
-	err = mhi_net_newlink(mhi_dev, ndev);
+	err = mhi_net_newlink(mhi_dev, ndev, info->ethernet_if);
 	if (err) {
 		free_netdev(ndev);
 		return err;
@@ -380,10 +419,17 @@ static void mhi_net_remove(struct mhi_device *mhi_dev)
 
 static const struct mhi_device_info mhi_hwip0 = {
 	.netname = "mhi_hwip%d",
+	.ethernet_if = false,
 };
 
 static const struct mhi_device_info mhi_swip0 = {
 	.netname = "mhi_swip%d",
+	.ethernet_if = false,
+};
+
+static const struct mhi_device_info mhi_eth0 = {
+	.netname = "eth%d",
+	.ethernet_if = true,
 };
 
 static const struct mhi_device_id mhi_net_id_table[] = {
@@ -391,6 +437,9 @@ static const struct mhi_device_id mhi_net_id_table[] = {
 	{ .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_SW1", .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