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