net: iosm: net driver

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@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wwan/iosm/iosm_ipc_wwan.c b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
new file mode 100644 (file)
index 0000000..1711b79
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
@@ -0,0 +1,351 @@
+// 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
+ * @ipc_wwan:  Pointer to iosm_wwan struct
+ * @netdev:    Pointer to network interface device structure
+ * @if_id:     Interface id for device.
+ * @ch_id:     IPC channel number for which interface device is created.
+ */
+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 (file)
index 0000000..4925f22
--- /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