drivers: net: ethernet: qualcomm: rmnet: Initial implementation

RmNet driver provides a transport agnostic MAP (multiplexing and
aggregation protocol) support in embedded module. Module provides
virtual network devices which can be attached to any IP-mode
physical device. This will be used to provide all MAP functionality
on future hardware in a single consistent location.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 170 insertions, 0 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
new file mode 100644
index 000000000000..c8b573d28dcf
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -0,0 +1,170 @@
+/* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ *
+ * RMNET Data virtual network driver
+ *
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <net/pkt_sched.h>
+#include "rmnet_config.h"
+#include "rmnet_handlers.h"
+#include "rmnet_private.h"
+#include "rmnet_map.h"
+#include "rmnet_vnd.h"
+
+/* RX/TX Fixup */
+
+void rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+}
+
+void rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+}
+
+/* Network Device Operations */
+
+static netdev_tx_t rmnet_vnd_start_xmit(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(dev);
+	if (priv->local_ep.egress_dev) {
+		rmnet_egress_handler(skb, &priv->local_ep);
+	} else {
+		dev->stats.tx_dropped++;
+		kfree_skb(skb);
+	}
+	return NETDEV_TX_OK;
+}
+
+static int rmnet_vnd_change_mtu(struct net_device *rmnet_dev, int new_mtu)
+{
+	if (new_mtu < 0 || new_mtu > RMNET_MAX_PACKET_SIZE)
+		return -EINVAL;
+
+	rmnet_dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops rmnet_vnd_ops = {
+	.ndo_start_xmit = rmnet_vnd_start_xmit,
+	.ndo_change_mtu = rmnet_vnd_change_mtu,
+};
+
+/* Called by kernel whenever a new rmnet<n> device is created. Sets MTU,
+ * flags, ARP type, needed headroom, etc...
+ */
+void rmnet_vnd_setup(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	netdev_dbg(rmnet_dev, "Setting up device %s\n", rmnet_dev->name);
+
+	rmnet_dev->netdev_ops = &rmnet_vnd_ops;
+	rmnet_dev->mtu = RMNET_DFLT_PACKET_SIZE;
+	rmnet_dev->needed_headroom = RMNET_NEEDED_HEADROOM;
+	random_ether_addr(rmnet_dev->dev_addr);
+	rmnet_dev->tx_queue_len = RMNET_TX_QUEUE_LEN;
+
+	/* Raw IP mode */
+	rmnet_dev->header_ops = NULL;  /* No header */
+	rmnet_dev->type = ARPHRD_RAWIP;
+	rmnet_dev->hard_header_len = 0;
+	rmnet_dev->flags &= ~(IFF_BROADCAST | IFF_MULTICAST);
+
+	rmnet_dev->needs_free_netdev = true;
+}
+
+/* Exposed API */
+
+int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
+		      struct rmnet_real_dev_info *r)
+{
+	int rc;
+
+	if (r->rmnet_devices[id])
+		return -EINVAL;
+
+	rc = register_netdevice(rmnet_dev);
+	if (!rc) {
+		r->rmnet_devices[id] = rmnet_dev;
+		r->nr_rmnet_devs++;
+		rmnet_dev->rtnl_link_ops = &rmnet_link_ops;
+	}
+
+	return rc;
+}
+
+int rmnet_vnd_dellink(u8 id, struct rmnet_real_dev_info *r)
+{
+	if (id >= RMNET_MAX_VND || !r->rmnet_devices[id])
+		return -EINVAL;
+
+	r->rmnet_devices[id] = NULL;
+	r->nr_rmnet_devs--;
+	return 0;
+}
+
+u8 rmnet_vnd_get_mux(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	return priv->mux_id;
+}
+
+void rmnet_vnd_set_mux(struct net_device *rmnet_dev, u8 mux_id)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(rmnet_dev);
+	priv->mux_id = mux_id;
+}
+
+/* Gets the logical endpoint configuration for a RmNet virtual network device
+ * node. Caller should confirm that devices is a RmNet VND before calling.
+ */
+struct rmnet_endpoint *rmnet_vnd_get_endpoint(struct net_device *rmnet_dev)
+{
+	struct rmnet_priv *priv;
+
+	if (!rmnet_dev)
+		return NULL;
+
+	priv = netdev_priv(rmnet_dev);
+
+	return &priv->local_ep;
+}
+
+int rmnet_vnd_do_flow_control(struct net_device *rmnet_dev, int enable)
+{
+	netdev_dbg(rmnet_dev, "Setting VND TX queue state to %d\n", enable);
+	/* Although we expect similar number of enable/disable
+	 * commands, optimize for the disable. That is more
+	 * latency sensitive than enable
+	 */
+	if (unlikely(enable))
+		netif_wake_queue(rmnet_dev);
+	else
+		netif_stop_queue(rmnet_dev);
+
+	return 0;
+}