1) Create net device & implement net operations for data/IP communication.
2) Bind IP Link to mux IP session for simultaneous IP traffic.
Signed-off-by: M Chetan Kumar <m.chetan.kumar@xxxxxxxxx>
---
v4:
* Adapt to wwan subsystem rtnet_link ops.
* Fix stats and RCU bugs in RX.
v3:
* Clean-up DSS channel implementation.
* Aligned ipc_ prefix for function name to be consistent across file.
v2:
* Removed Ethernet header & VLAN tag handling from wwan net driver.
* Implement rtnet_link interface for IP traffic handling.
---
drivers/net/wwan/iosm/iosm_ipc_wwan.c | 350 ++++++++++++++++++++++++++
drivers/net/wwan/iosm/iosm_ipc_wwan.h | 55 ++++
2 files changed, 405 insertions(+)
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_wwan.c
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_wwan.h
diff --git a/drivers/net/wwan/iosm/iosm_ipc_wwan.c b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
new file mode 100644
index 000000000000..80306b37c2b5
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+#include <linux/wwan.h>
+
+#include "iosm_ipc_chnl_cfg.h"
+#include "iosm_ipc_imem_ops.h"
+#include "iosm_ipc_wwan.h"
+
+#define IOSM_IP_TYPE_MASK 0xF0
+#define IOSM_IP_TYPE_IPV4 0x40
+#define IOSM_IP_TYPE_IPV6 0x60
+
+#define IOSM_IF_ID_PAYLOAD 2
+
+/**
+ * struct iosm_netdev_priv - netdev private data
+ * @if_id: Interface id for device.
+ * @ch_id: IPC channel number for which interface device is created.
+ * @ipc_wwan: Pointer to iosm_wwan struct
+ */
+struct iosm_netdev_priv {
+ struct iosm_wwan *ipc_wwan;
+ struct net_device *netdev;
+ int if_id;
+ int ch_id;
+};
+
+/**
+ * struct iosm_wwan - This structure contains information about WWAN root device
+ * and interface to the IPC layer.
+ * @ipc_imem: Pointer to imem data-struct
+ * @sub_netlist: List of active netdevs
+ * @dev: Pointer device structure
+ * @if_mutex: Mutex used for add and remove interface id
+ */
+struct iosm_wwan {
+ struct iosm_imem *ipc_imem;
+ struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];
+ struct device *dev;
+ struct mutex if_mutex; /* Mutex used for add and remove interface id */
+};
+
+/* Bring-up the wwan net link */
+static int ipc_wwan_link_open(struct net_device *netdev)
+{
+ struct iosm_netdev_priv *priv = netdev_priv(netdev);
+ struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
+ int if_id = priv->if_id;
+ int ret;
+
+ if (if_id < IP_MUX_SESSION_START ||
+ if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
+ return -EINVAL;
+
+ mutex_lock(&ipc_wwan->if_mutex);
+
+ /* get channel id */
+ priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);
+
+ if (priv->ch_id < 0) {
+ dev_err(ipc_wwan->dev,
+ "cannot connect wwan0 & id %d to the IPC mem layer",
+ if_id);
+ ret = -ENODEV;
+ goto out;
+ }
+
+ /* enable tx path, DL data may follow */
+ netif_start_queue(netdev);
+
+ dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",
+ priv->ch_id, priv->if_id);
+
+ ret = 0;
+out:
+ mutex_unlock(&ipc_wwan->if_mutex);
+ return ret;
+}
+
+/* Bring-down the wwan net link */
+static int ipc_wwan_link_stop(struct net_device *netdev)
+{
+ struct iosm_netdev_priv *priv = netdev_priv(netdev);
+
+ netif_stop_queue(netdev);
+
+ mutex_lock(&priv->ipc_wwan->if_mutex);
+ ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,
+ priv->ch_id);
+ priv->ch_id = -1;
+ mutex_unlock(&priv->ipc_wwan->if_mutex);
+
+ return 0;
+}
+
+/* Transmit a packet */
+static int ipc_wwan_link_transmit(struct sk_buff *skb,
+ struct net_device *netdev)
+{
+ struct iosm_netdev_priv *priv = netdev_priv(netdev);
+ struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
+ int if_id = priv->if_id;
+ int ret;
+
+ /* Interface IDs from 1 to 8 are for IP data
+ * & from 257 to 261 are for non-IP data
+ */
+ if (if_id < IP_MUX_SESSION_START ||
+ if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
+ return -EINVAL;
+
+ /* Send the SKB to device for transmission */
+ ret = ipc_imem_sys_wwan_transmit(ipc_wwan->ipc_imem,
+ if_id, priv->ch_id, skb);
+
+ /* Return code of zero is success */
+ if (ret == 0) {
+ ret = NETDEV_TX_OK;
+ } else if (ret == -EBUSY) {
+ ret = NETDEV_TX_BUSY;
+ dev_err(ipc_wwan->dev, "unable to push packets");
+ } else {
+ goto exit;
+ }
+
+ return ret;
+
+exit:
+ /* Log any skb drop */
+ if (if_id)
+ dev_dbg(ipc_wwan->dev, "skb dropped. IF_ID: %d, ret: %d", if_id,
+ ret);
+
+ dev_kfree_skb_any(skb);
+ return ret;
+}
+
+/* Ops structure for wwan net link */
+static const struct net_device_ops ipc_inm_ops = {
+ .ndo_open = ipc_wwan_link_open,
+ .ndo_stop = ipc_wwan_link_stop,
+ .ndo_start_xmit = ipc_wwan_link_transmit,
+};
+
+/* Setup function for creating new net link */
+static void ipc_wwan_setup(struct net_device *iosm_dev)
+{
+ iosm_dev->header_ops = NULL;
+ iosm_dev->hard_header_len = 0;
+ iosm_dev->priv_flags |= IFF_NO_QUEUE;
+
+ iosm_dev->type = ARPHRD_NONE;
+ iosm_dev->min_mtu = ETH_MIN_MTU;
+ iosm_dev->max_mtu = ETH_MAX_MTU;
+
+ iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+
+ iosm_dev->netdev_ops = &ipc_inm_ops;
+}
+
+/* Create new wwan net link */
+static int ipc_wwan_newlink(void *ctxt, struct net_device *dev,
+ u32 if_id, struct netlink_ext_ack *extack)
+{
+ struct iosm_wwan *ipc_wwan = ctxt;
+ struct iosm_netdev_priv *priv;
+ int err;
+
+ if (if_id < IP_MUX_SESSION_START ||
+ if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
+ return -EINVAL;
+
+ priv = netdev_priv(dev);
+ priv->if_id = if_id;
+ priv->netdev = dev;
+ priv->ipc_wwan = ipc_wwan;
+
+ mutex_lock(&ipc_wwan->if_mutex);
+ if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id])) {
+ err = -EBUSY;
+ goto out_unlock;
+ }
+
+ err = register_netdevice(dev);
+ if (err)
+ goto out_unlock;
+
+ rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);
+ mutex_unlock(&ipc_wwan->if_mutex);
+
+ netif_device_attach(dev);
+
+ return 0;
+
+out_unlock:
+ mutex_unlock(&ipc_wwan->if_mutex);
+ return err;
+}
+
+static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,
+ struct list_head *head)
+{
+ struct iosm_wwan *ipc_wwan = ctxt;
+ struct iosm_netdev_priv *priv = netdev_priv(dev);
+ int if_id = priv->if_id;
+
+ if (WARN_ON(if_id < IP_MUX_SESSION_START ||
+ if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))
+ return;
+
+ mutex_lock(&ipc_wwan->if_mutex);
+
+ if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))
+ goto unlock;
+
+ RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);
+ /* unregistering includes synchronize_net() */
+ unregister_netdevice(dev);
+
+unlock:
+ mutex_unlock(&ipc_wwan->if_mutex);
+}
+
+static const struct wwan_ops iosm_wwan_ops = {
+ .priv_size = sizeof(struct iosm_netdev_priv),
+ .setup = ipc_wwan_setup,
+ .newlink = ipc_wwan_newlink,
+ .dellink = ipc_wwan_dellink,
+};
+
+int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,
+ bool dss, int if_id)
+{
+ struct sk_buff *skb = skb_arg;
+ struct net_device_stats *stats;
+ struct iosm_netdev_priv *priv;
+ int ret;
+
+ if ((skb->data[0] & IOSM_IP_TYPE_MASK) == IOSM_IP_TYPE_IPV4)
+ skb->protocol = htons(ETH_P_IP);
+ else if ((skb->data[0] & IOSM_IP_TYPE_MASK) ==
+ IOSM_IP_TYPE_IPV6)
+ skb->protocol = htons(ETH_P_IPV6);
+
+ skb->pkt_type = PACKET_HOST;
+
+ if (if_id < (IP_MUX_SESSION_START - 1) ||
+ if_id > (IP_MUX_SESSION_END - 1)) {
+ ret = -EINVAL;
+ goto free;
+ }
+
+ rcu_read_lock();
+ priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
+ if (!priv) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ skb->dev = priv->netdev;
+ stats = &priv->netdev->stats;
+ stats->rx_packets++;
+ stats->rx_bytes += skb->len;
+
+ ret = netif_rx(skb);
+ skb = NULL;
+unlock:
+ rcu_read_unlock();
+free:
+ dev_kfree_skb(skb);
+ return ret;
+}
+
+void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int if_id, bool on)
+{
+ struct net_device *netdev;
+ struct iosm_netdev_priv *priv;
+ bool is_tx_blk;
+
+ rcu_read_lock();
+ priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
+ if (!priv) {
+ rcu_read_unlock();
+ return;
+ }
+
+ netdev = priv->netdev;
+
+ is_tx_blk = netif_queue_stopped(netdev);
+
+ if (on)
+ dev_dbg(ipc_wwan->dev, "session id[%d]: flowctrl enable",
+ if_id);
+
+ if (on && !is_tx_blk)
+ netif_stop_queue(netdev);
+ else if (!on && is_tx_blk)
+ netif_wake_queue(netdev);
+ rcu_read_unlock();
+}
+
+struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)
+{
+ struct iosm_wwan *ipc_wwan;
+
+ ipc_wwan = kzalloc(sizeof(*ipc_wwan), GFP_KERNEL);
+ if (!ipc_wwan)
+ return NULL;
+
+ ipc_wwan->dev = dev;
+ ipc_wwan->ipc_imem = ipc_imem;
+
+ if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan)) {
+ kfree(ipc_wwan);
+ return NULL;
+ }
+
+ mutex_init(&ipc_wwan->if_mutex);
+
+ return ipc_wwan;
+}
+
+void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan)
+{
+ int if_id;
+
+ wwan_unregister_ops(ipc_wwan->dev);
+
+ for (if_id = 0; if_id < ARRAY_SIZE(ipc_wwan->sub_netlist); if_id++) {
+ struct iosm_netdev_priv *priv;
+
+ priv = rcu_access_pointer(ipc_wwan->sub_netlist[if_id]);
+ if (!priv)
+ continue;
+
+ rtnl_lock();
+ ipc_wwan_dellink(ipc_wwan, priv->netdev, NULL);
+ rtnl_unlock();
+ }
+
+ mutex_destroy(&ipc_wwan->if_mutex);
+
+ kfree(ipc_wwan);
+}
diff --git a/drivers/net/wwan/iosm/iosm_ipc_wwan.h b/drivers/net/wwan/iosm/iosm_ipc_wwan.h
new file mode 100644
index 000000000000..4925f22dff0a
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_wwan.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_WWAN_H
+#define IOSM_IPC_WWAN_H
+
+/**
+ * ipc_wwan_init - Allocate, Init and register WWAN device
+ * @ipc_imem: Pointer to imem data-struct
+ * @dev: Pointer to device structure
+ *
+ * Returns: Pointer to instance on success else NULL
+ */
+struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev);
+
+/**
+ * ipc_wwan_deinit - Unregister and free WWAN device, clear pointer
+ * @ipc_wwan: Pointer to wwan instance data
+ */
+void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan);
+
+/**
+ * ipc_wwan_receive - Receive a downlink packet from CP.
+ * @ipc_wwan: Pointer to wwan instance
+ * @skb_arg: Pointer to struct sk_buff
+ * @dss: Set to true if interafce id is from 257 to 261,
+ * else false
+ * @if_id: Interface ID
+ *
+ * Return: 0 on success and failure value on error
+ */
+int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,
+ bool dss, int if_id);
+
+/**
+ * ipc_wwan_tx_flowctrl - Enable/Disable TX flow control
+ * @ipc_wwan: Pointer to wwan instance
+ * @id: Ipc mux channel session id
+ * @on: if true then flow ctrl would be enabled else disable
+ *
+ */
+void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int id, bool on);
+
+/**
+ * ipc_wwan_is_tx_stopped - Checks if Tx stopped for a Interface id.
+ * @ipc_wwan: Pointer to wwan instance
+ * @id: Ipc mux channel session id
+ *
+ * Return: true if stopped, false otherwise
+ */
+bool ipc_wwan_is_tx_stopped(struct iosm_wwan *ipc_wwan, int id);
+
+#endif
--
2.25.1
