wwan/iosm/iosm_ipc_wwan.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) 2020-21 Intel Corporation.
0004  */
0005
0006 #include <linux/etherdevice.h>
0007 #include <linux/if_arp.h>
0008 #include <linux/if_link.h>
0009 #include <linux/rtnetlink.h>
0010 #include <linux/wwan.h>
0011 #include <net/pkt_sched.h>
0012
0013 #include "iosm_ipc_chnl_cfg.h"
0014 #include "iosm_ipc_imem_ops.h"
0015 #include "iosm_ipc_wwan.h"
0016
0017 #define IOSM_IP_TYPE_MASK 0xF0
0018 #define IOSM_IP_TYPE_IPV4 0x40
0019 #define IOSM_IP_TYPE_IPV6 0x60
0020
0021 #define IOSM_IF_ID_PAYLOAD 2
0022
0023 /**
0024  * struct iosm_netdev_priv - netdev WWAN driver specific private data
0025  * @ipc_wwan:   Pointer to iosm_wwan struct
0026  * @netdev: Pointer to network interface device structure
0027  * @if_id:  Interface id for device.
0028  * @ch_id:  IPC channel number for which interface device is created.
0029  */
0030 struct iosm_netdev_priv {
0031     struct iosm_wwan *ipc_wwan;
0032     struct net_device *netdev;
0033     int if_id;
0034     int ch_id;
0035 };
0036
0037 /**
0038  * struct iosm_wwan - This structure contains information about WWAN root device
0039  *            and interface to the IPC layer.
0040  * @ipc_imem:       Pointer to imem data-struct
0041  * @sub_netlist:    List of active netdevs
0042  * @dev:        Pointer device structure
0043  * @if_mutex:       Mutex used for add and remove interface id
0044  */
0045 struct iosm_wwan {
0046     struct iosm_imem *ipc_imem;
0047     struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];
0048     struct device *dev;
0049     struct mutex if_mutex; /* Mutex used for add and remove interface id */
0050 };
0051
0052 /* Bring-up the wwan net link */
0053 static int ipc_wwan_link_open(struct net_device *netdev)
0054 {
0055     struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
0056     struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
0057     int if_id = priv->if_id;
0058     int ret;
0059
0060     if (if_id < IP_MUX_SESSION_START ||
0061         if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
0062         return -EINVAL;
0063
0064     mutex_lock(&ipc_wwan->if_mutex);
0065
0066     /* get channel id */
0067     priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);
0068
0069     if (priv->ch_id < 0) {
0070         dev_err(ipc_wwan->dev,
0071             "cannot connect wwan0 & id %d to the IPC mem layer",
0072             if_id);
0073         ret = -ENODEV;
0074         goto out;
0075     }
0076
0077     /* enable tx path, DL data may follow */
0078     netif_start_queue(netdev);
0079
0080     dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",
0081         priv->ch_id, priv->if_id);
0082
0083     ret = 0;
0084 out:
0085     mutex_unlock(&ipc_wwan->if_mutex);
0086     return ret;
0087 }
0088
0089 /* Bring-down the wwan net link */
0090 static int ipc_wwan_link_stop(struct net_device *netdev)
0091 {
0092     struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
0093
0094     netif_stop_queue(netdev);
0095
0096     mutex_lock(&priv->ipc_wwan->if_mutex);
0097     ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,
0098                 priv->ch_id);
0099     priv->ch_id = -1;
0100     mutex_unlock(&priv->ipc_wwan->if_mutex);
0101
0102     return 0;
0103 }
0104
0105 /* Transmit a packet */
0106 static int ipc_wwan_link_transmit(struct sk_buff *skb,
0107                   struct net_device *netdev)
0108 {
0109     struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
0110     struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
0111     unsigned int len = skb->len;
0112     int if_id = priv->if_id;
0113     int ret;
0114
0115     /* Interface IDs from 1 to 8 are for IP data
0116      * & from 257 to 261 are for non-IP data
0117      */
0118     if (if_id < IP_MUX_SESSION_START ||
0119         if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
0120         return -EINVAL;
0121
0122     /* Send the SKB to device for transmission */
0123     ret = ipc_imem_sys_wwan_transmit(ipc_wwan->ipc_imem,
0124                      if_id, priv->ch_id, skb);
0125
0126     /* Return code of zero is success */
0127     if (ret == 0) {
0128         netdev->stats.tx_packets++;
0129         netdev->stats.tx_bytes += len;
0130         ret = NETDEV_TX_OK;
0131     } else if (ret == -EBUSY) {
0132         ret = NETDEV_TX_BUSY;
0133         dev_err(ipc_wwan->dev, "unable to push packets");
0134     } else {
0135         goto exit;
0136     }
0137
0138     return ret;
0139
0140 exit:
0141     /* Log any skb drop */
0142     if (if_id)
0143         dev_dbg(ipc_wwan->dev, "skb dropped. IF_ID: %d, ret: %d", if_id,
0144             ret);
0145
0146     dev_kfree_skb_any(skb);
0147     netdev->stats.tx_dropped++;
0148     return NETDEV_TX_OK;
0149 }
0150
0151 /* Ops structure for wwan net link */
0152 static const struct net_device_ops ipc_inm_ops = {
0153     .ndo_open = ipc_wwan_link_open,
0154     .ndo_stop = ipc_wwan_link_stop,
0155     .ndo_start_xmit = ipc_wwan_link_transmit,
0156 };
0157
0158 /* Setup function for creating new net link */
0159 static void ipc_wwan_setup(struct net_device *iosm_dev)
0160 {
0161     iosm_dev->header_ops = NULL;
0162     iosm_dev->hard_header_len = 0;
0163     iosm_dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
0164
0165     iosm_dev->type = ARPHRD_NONE;
0166     iosm_dev->mtu = ETH_DATA_LEN;
0167     iosm_dev->min_mtu = ETH_MIN_MTU;
0168     iosm_dev->max_mtu = ETH_MAX_MTU;
0169
0170     iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;
0171
0172     iosm_dev->netdev_ops = &ipc_inm_ops;
0173 }
0174
0175 /* Create new wwan net link */
0176 static int ipc_wwan_newlink(void *ctxt, struct net_device *dev,
0177                 u32 if_id, struct netlink_ext_ack *extack)
0178 {
0179     struct iosm_wwan *ipc_wwan = ctxt;
0180     struct iosm_netdev_priv *priv;
0181     int err;
0182
0183     if (if_id < IP_MUX_SESSION_START ||
0184         if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
0185         return -EINVAL;
0186
0187     priv = wwan_netdev_drvpriv(dev);
0188     priv->if_id = if_id;
0189     priv->netdev = dev;
0190     priv->ipc_wwan = ipc_wwan;
0191
0192     mutex_lock(&ipc_wwan->if_mutex);
0193     if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id])) {
0194         err = -EBUSY;
0195         goto out_unlock;
0196     }
0197
0198     err = register_netdevice(dev);
0199     if (err)
0200         goto out_unlock;
0201
0202     rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);
0203     mutex_unlock(&ipc_wwan->if_mutex);
0204
0205     netif_device_attach(dev);
0206
0207     return 0;
0208
0209 out_unlock:
0210     mutex_unlock(&ipc_wwan->if_mutex);
0211     return err;
0212 }
0213
0214 static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,
0215                  struct list_head *head)
0216 {
0217     struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(dev);
0218     struct iosm_wwan *ipc_wwan = ctxt;
0219     int if_id = priv->if_id;
0220
0221     if (WARN_ON(if_id < IP_MUX_SESSION_START ||
0222             if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))
0223         return;
0224
0225     mutex_lock(&ipc_wwan->if_mutex);
0226
0227     if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))
0228         goto unlock;
0229
0230     RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);
0231     /* unregistering includes synchronize_net() */
0232     unregister_netdevice_queue(dev, head);
0233
0234 unlock:
0235     mutex_unlock(&ipc_wwan->if_mutex);
0236 }
0237
0238 static const struct wwan_ops iosm_wwan_ops = {
0239     .priv_size = sizeof(struct iosm_netdev_priv),
0240     .setup = ipc_wwan_setup,
0241     .newlink = ipc_wwan_newlink,
0242     .dellink = ipc_wwan_dellink,
0243 };
0244
0245 int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,
0246              bool dss, int if_id)
0247 {
0248     struct sk_buff *skb = skb_arg;
0249     struct net_device_stats *stats;
0250     struct iosm_netdev_priv *priv;
0251     int ret;
0252
0253     if ((skb->data[0] & IOSM_IP_TYPE_MASK) == IOSM_IP_TYPE_IPV4)
0254         skb->protocol = htons(ETH_P_IP);
0255     else if ((skb->data[0] & IOSM_IP_TYPE_MASK) ==
0256          IOSM_IP_TYPE_IPV6)
0257         skb->protocol = htons(ETH_P_IPV6);
0258
0259     skb->pkt_type = PACKET_HOST;
0260
0261     if (if_id < IP_MUX_SESSION_START ||
0262         if_id > IP_MUX_SESSION_END) {
0263         ret = -EINVAL;
0264         goto free;
0265     }
0266
0267     rcu_read_lock();
0268     priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
0269     if (!priv) {
0270         ret = -EINVAL;
0271         goto unlock;
0272     }
0273     skb->dev = priv->netdev;
0274     stats = &priv->netdev->stats;
0275     stats->rx_packets++;
0276     stats->rx_bytes += skb->len;
0277
0278     ret = netif_rx(skb);
0279     skb = NULL;
0280 unlock:
0281     rcu_read_unlock();
0282 free:
0283     dev_kfree_skb(skb);
0284     return ret;
0285 }
0286
0287 void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int if_id, bool on)
0288 {
0289     struct net_device *netdev;
0290     struct iosm_netdev_priv *priv;
0291     bool is_tx_blk;
0292
0293     rcu_read_lock();
0294     priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
0295     if (!priv) {
0296         rcu_read_unlock();
0297         return;
0298     }
0299
0300     netdev = priv->netdev;
0301
0302     is_tx_blk = netif_queue_stopped(netdev);
0303
0304     if (on)
0305         dev_dbg(ipc_wwan->dev, "session id[%d]: flowctrl enable",
0306             if_id);
0307
0308     if (on && !is_tx_blk)
0309         netif_stop_queue(netdev);
0310     else if (!on && is_tx_blk)
0311         netif_wake_queue(netdev);
0312     rcu_read_unlock();
0313 }
0314
0315 struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)
0316 {
0317     struct iosm_wwan *ipc_wwan;
0318
0319     ipc_wwan = kzalloc(sizeof(*ipc_wwan), GFP_KERNEL);
0320     if (!ipc_wwan)
0321         return NULL;
0322
0323     ipc_wwan->dev = dev;
0324     ipc_wwan->ipc_imem = ipc_imem;
0325
0326     /* WWAN core will create a netdev for the default IP MUX channel */
0327     if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan,
0328                   IP_MUX_SESSION_DEFAULT)) {
0329         kfree(ipc_wwan);
0330         return NULL;
0331     }
0332
0333     mutex_init(&ipc_wwan->if_mutex);
0334
0335     return ipc_wwan;
0336 }
0337
0338 void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan)
0339 {
0340     /* This call will remove all child netdev(s) */
0341     wwan_unregister_ops(ipc_wwan->dev);
0342
0343     mutex_destroy(&ipc_wwan->if_mutex);
0344
0345     kfree(ipc_wwan);
0346 }