1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020-21 Intel Corporation.
4  */
5 
6 #include <linux/etherdevice.h>
7 #include <linux/if_arp.h>
8 #include <linux/if_link.h>
9 #include <linux/rtnetlink.h>
10 #include <linux/wwan.h>
11 #include <net/pkt_sched.h>
12 
13 #include "iosm_ipc_chnl_cfg.h"
14 #include "iosm_ipc_imem_ops.h"
15 #include "iosm_ipc_wwan.h"
16 
17 #define IOSM_IP_TYPE_MASK 0xF0
18 #define IOSM_IP_TYPE_IPV4 0x40
19 #define IOSM_IP_TYPE_IPV6 0x60
20 
21 #define IOSM_IF_ID_PAYLOAD 2
22 
23 /**
24  * struct iosm_netdev_priv - netdev WWAN driver specific private data
25  * @ipc_wwan:	Pointer to iosm_wwan struct
26  * @netdev:	Pointer to network interface device structure
27  * @if_id:	Interface id for device.
28  * @ch_id:	IPC channel number for which interface device is created.
29  */
30 struct iosm_netdev_priv {
31 	struct iosm_wwan *ipc_wwan;
32 	struct net_device *netdev;
33 	int if_id;
34 	int ch_id;
35 };
36 
37 /**
38  * struct iosm_wwan - This structure contains information about WWAN root device
39  *		      and interface to the IPC layer.
40  * @ipc_imem:		Pointer to imem data-struct
41  * @sub_netlist:	List of active netdevs
42  * @dev:		Pointer device structure
43  * @if_mutex:		Mutex used for add and remove interface id
44  */
45 struct iosm_wwan {
46 	struct iosm_imem *ipc_imem;
47 	struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];
48 	struct device *dev;
49 	struct mutex if_mutex; /* Mutex used for add and remove interface id */
50 };
51 
52 /* Bring-up the wwan net link */
53 static int ipc_wwan_link_open(struct net_device *netdev)
54 {
55 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
56 	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
57 	int if_id = priv->if_id;
58 	int ret;
59 
60 	if (if_id < IP_MUX_SESSION_START ||
61 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
62 		return -EINVAL;
63 
64 	mutex_lock(&ipc_wwan->if_mutex);
65 
66 	/* get channel id */
67 	priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);
68 
69 	if (priv->ch_id < 0) {
70 		dev_err(ipc_wwan->dev,
71 			"cannot connect wwan0 & id %d to the IPC mem layer",
72 			if_id);
73 		ret = -ENODEV;
74 		goto out;
75 	}
76 
77 	/* enable tx path, DL data may follow */
78 	netif_start_queue(netdev);
79 
80 	dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",
81 		priv->ch_id, priv->if_id);
82 
83 	ret = 0;
84 out:
85 	mutex_unlock(&ipc_wwan->if_mutex);
86 	return ret;
87 }
88 
89 /* Bring-down the wwan net link */
90 static int ipc_wwan_link_stop(struct net_device *netdev)
91 {
92 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
93 
94 	netif_stop_queue(netdev);
95 
96 	mutex_lock(&priv->ipc_wwan->if_mutex);
97 	ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,
98 				priv->ch_id);
99 	priv->ch_id = -1;
100 	mutex_unlock(&priv->ipc_wwan->if_mutex);
101 
102 	return 0;
103 }
104 
105 /* Transmit a packet */
106 static netdev_tx_t ipc_wwan_link_transmit(struct sk_buff *skb,
107 					  struct net_device *netdev)
108 {
109 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
110 	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
111 	unsigned int len = skb->len;
112 	int if_id = priv->if_id;
113 	int ret;
114 
115 	/* Interface IDs from 1 to 8 are for IP data
116 	 * & from 257 to 261 are for non-IP data
117 	 */
118 	if (if_id < IP_MUX_SESSION_START ||
119 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
120 		return -EINVAL;
121 
122 	/* Send the SKB to device for transmission */
123 	ret = ipc_imem_sys_wwan_transmit(ipc_wwan->ipc_imem,
124 					 if_id, priv->ch_id, skb);
125 
126 	/* Return code of zero is success */
127 	if (ret == 0) {
128 		netdev->stats.tx_packets++;
129 		netdev->stats.tx_bytes += len;
130 		ret = NETDEV_TX_OK;
131 	} else if (ret == -EBUSY) {
132 		ret = NETDEV_TX_BUSY;
133 		dev_err(ipc_wwan->dev, "unable to push packets");
134 	} else {
135 		goto exit;
136 	}
137 
138 	return ret;
139 
140 exit:
141 	/* Log any skb drop */
142 	if (if_id)
143 		dev_dbg(ipc_wwan->dev, "skb dropped. IF_ID: %d, ret: %d", if_id,
144 			ret);
145 
146 	dev_kfree_skb_any(skb);
147 	netdev->stats.tx_dropped++;
148 	return NETDEV_TX_OK;
149 }
150 
151 /* Ops structure for wwan net link */
152 static const struct net_device_ops ipc_inm_ops = {
153 	.ndo_open = ipc_wwan_link_open,
154 	.ndo_stop = ipc_wwan_link_stop,
155 	.ndo_start_xmit = ipc_wwan_link_transmit,
156 };
157 
158 /* Setup function for creating new net link */
159 static void ipc_wwan_setup(struct net_device *iosm_dev)
160 {
161 	iosm_dev->header_ops = NULL;
162 	iosm_dev->hard_header_len = 0;
163 	iosm_dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
164 
165 	iosm_dev->type = ARPHRD_NONE;
166 	iosm_dev->mtu = ETH_DATA_LEN;
167 	iosm_dev->min_mtu = ETH_MIN_MTU;
168 	iosm_dev->max_mtu = ETH_MAX_MTU;
169 
170 	iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;
171 
172 	iosm_dev->netdev_ops = &ipc_inm_ops;
173 }
174 
175 /* Create new wwan net link */
176 static int ipc_wwan_newlink(void *ctxt, struct net_device *dev,
177 			    u32 if_id, struct netlink_ext_ack *extack)
178 {
179 	struct iosm_wwan *ipc_wwan = ctxt;
180 	struct iosm_netdev_priv *priv;
181 	int err;
182 
183 	if (if_id < IP_MUX_SESSION_START ||
184 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
185 		return -EINVAL;
186 
187 	priv = wwan_netdev_drvpriv(dev);
188 	priv->if_id = if_id;
189 	priv->netdev = dev;
190 	priv->ipc_wwan = ipc_wwan;
191 
192 	mutex_lock(&ipc_wwan->if_mutex);
193 	if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id])) {
194 		err = -EBUSY;
195 		goto out_unlock;
196 	}
197 
198 	err = register_netdevice(dev);
199 	if (err)
200 		goto out_unlock;
201 
202 	rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);
203 	mutex_unlock(&ipc_wwan->if_mutex);
204 
205 	netif_device_attach(dev);
206 
207 	return 0;
208 
209 out_unlock:
210 	mutex_unlock(&ipc_wwan->if_mutex);
211 	return err;
212 }
213 
214 static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,
215 			     struct list_head *head)
216 {
217 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(dev);
218 	struct iosm_wwan *ipc_wwan = ctxt;
219 	int if_id = priv->if_id;
220 
221 	if (WARN_ON(if_id < IP_MUX_SESSION_START ||
222 		    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))
223 		return;
224 
225 	mutex_lock(&ipc_wwan->if_mutex);
226 
227 	if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))
228 		goto unlock;
229 
230 	RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);
231 	/* unregistering includes synchronize_net() */
232 	unregister_netdevice_queue(dev, head);
233 
234 unlock:
235 	mutex_unlock(&ipc_wwan->if_mutex);
236 }
237 
238 static const struct wwan_ops iosm_wwan_ops = {
239 	.priv_size = sizeof(struct iosm_netdev_priv),
240 	.setup = ipc_wwan_setup,
241 	.newlink = ipc_wwan_newlink,
242 	.dellink = ipc_wwan_dellink,
243 };
244 
245 int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,
246 		     bool dss, int if_id)
247 {
248 	struct sk_buff *skb = skb_arg;
249 	struct net_device_stats *stats;
250 	struct iosm_netdev_priv *priv;
251 	int ret;
252 
253 	if ((skb->data[0] & IOSM_IP_TYPE_MASK) == IOSM_IP_TYPE_IPV4)
254 		skb->protocol = htons(ETH_P_IP);
255 	else if ((skb->data[0] & IOSM_IP_TYPE_MASK) ==
256 		 IOSM_IP_TYPE_IPV6)
257 		skb->protocol = htons(ETH_P_IPV6);
258 
259 	skb->pkt_type = PACKET_HOST;
260 
261 	if (if_id < IP_MUX_SESSION_START ||
262 	    if_id > IP_MUX_SESSION_END) {
263 		ret = -EINVAL;
264 		goto free;
265 	}
266 
267 	rcu_read_lock();
268 	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
269 	if (!priv) {
270 		ret = -EINVAL;
271 		goto unlock;
272 	}
273 	skb->dev = priv->netdev;
274 	stats = &priv->netdev->stats;
275 	stats->rx_packets++;
276 	stats->rx_bytes += skb->len;
277 
278 	ret = netif_rx(skb);
279 	skb = NULL;
280 unlock:
281 	rcu_read_unlock();
282 free:
283 	dev_kfree_skb(skb);
284 	return ret;
285 }
286 
287 void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int if_id, bool on)
288 {
289 	struct net_device *netdev;
290 	struct iosm_netdev_priv *priv;
291 	bool is_tx_blk;
292 
293 	rcu_read_lock();
294 	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
295 	if (!priv) {
296 		rcu_read_unlock();
297 		return;
298 	}
299 
300 	netdev = priv->netdev;
301 
302 	is_tx_blk = netif_queue_stopped(netdev);
303 
304 	if (on)
305 		dev_dbg(ipc_wwan->dev, "session id[%d]: flowctrl enable",
306 			if_id);
307 
308 	if (on && !is_tx_blk)
309 		netif_stop_queue(netdev);
310 	else if (!on && is_tx_blk)
311 		netif_wake_queue(netdev);
312 	rcu_read_unlock();
313 }
314 
315 struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)
316 {
317 	struct iosm_wwan *ipc_wwan;
318 
319 	ipc_wwan = kzalloc(sizeof(*ipc_wwan), GFP_KERNEL);
320 	if (!ipc_wwan)
321 		return NULL;
322 
323 	ipc_wwan->dev = dev;
324 	ipc_wwan->ipc_imem = ipc_imem;
325 
326 	mutex_init(&ipc_wwan->if_mutex);
327 
328 	/* WWAN core will create a netdev for the default IP MUX channel */
329 	if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan,
330 			      IP_MUX_SESSION_DEFAULT)) {
331 		mutex_destroy(&ipc_wwan->if_mutex);
332 		kfree(ipc_wwan);
333 		return NULL;
334 	}
335 
336 	return ipc_wwan;
337 }
338 
339 void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan)
340 {
341 	/* This call will remove all child netdev(s) */
342 	wwan_unregister_ops(ipc_wwan->dev);
343 
344 	mutex_destroy(&ipc_wwan->if_mutex);
345 
346 	kfree(ipc_wwan);
347 }
348