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  */
44 struct iosm_wwan {
45 	struct iosm_imem *ipc_imem;
46 	struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];
47 	struct device *dev;
48 };
49 
50 /* Bring-up the wwan net link */
ipc_wwan_link_open(struct net_device * netdev)51 static int ipc_wwan_link_open(struct net_device *netdev)
52 {
53 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
54 	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
55 	int if_id = priv->if_id;
56 
57 	if (if_id < IP_MUX_SESSION_START ||
58 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
59 		return -EINVAL;
60 
61 	/* get channel id */
62 	priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);
63 
64 	if (priv->ch_id < 0) {
65 		dev_err(ipc_wwan->dev,
66 			"cannot connect wwan0 & id %d to the IPC mem layer",
67 			if_id);
68 		return -ENODEV;
69 	}
70 
71 	/* enable tx path, DL data may follow */
72 	netif_start_queue(netdev);
73 
74 	dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",
75 		priv->ch_id, priv->if_id);
76 
77 	return 0;
78 }
79 
80 /* Bring-down the wwan net link */
ipc_wwan_link_stop(struct net_device * netdev)81 static int ipc_wwan_link_stop(struct net_device *netdev)
82 {
83 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
84 
85 	netif_stop_queue(netdev);
86 
87 	ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,
88 				priv->ch_id);
89 	priv->ch_id = -1;
90 
91 	return 0;
92 }
93 
94 /* Transmit a packet */
ipc_wwan_link_transmit(struct sk_buff * skb,struct net_device * netdev)95 static netdev_tx_t ipc_wwan_link_transmit(struct sk_buff *skb,
96 					  struct net_device *netdev)
97 {
98 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);
99 	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;
100 	unsigned int len = skb->len;
101 	int if_id = priv->if_id;
102 	int ret;
103 
104 	/* Interface IDs from 1 to 8 are for IP data
105 	 * & from 257 to 261 are for non-IP data
106 	 */
107 	if (if_id < IP_MUX_SESSION_START ||
108 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
109 		return -EINVAL;
110 
111 	/* Send the SKB to device for transmission */
112 	ret = ipc_imem_sys_wwan_transmit(ipc_wwan->ipc_imem,
113 					 if_id, priv->ch_id, skb);
114 
115 	/* Return code of zero is success */
116 	if (ret == 0) {
117 		netdev->stats.tx_packets++;
118 		netdev->stats.tx_bytes += len;
119 		ret = NETDEV_TX_OK;
120 	} else if (ret == -EBUSY) {
121 		ret = NETDEV_TX_BUSY;
122 		dev_err(ipc_wwan->dev, "unable to push packets");
123 	} else {
124 		goto exit;
125 	}
126 
127 	return ret;
128 
129 exit:
130 	/* Log any skb drop */
131 	if (if_id)
132 		dev_dbg(ipc_wwan->dev, "skb dropped. IF_ID: %d, ret: %d", if_id,
133 			ret);
134 
135 	dev_kfree_skb_any(skb);
136 	netdev->stats.tx_dropped++;
137 	return NETDEV_TX_OK;
138 }
139 
140 /* Ops structure for wwan net link */
141 static const struct net_device_ops ipc_inm_ops = {
142 	.ndo_open = ipc_wwan_link_open,
143 	.ndo_stop = ipc_wwan_link_stop,
144 	.ndo_start_xmit = ipc_wwan_link_transmit,
145 };
146 
147 /* Setup function for creating new net link */
ipc_wwan_setup(struct net_device * iosm_dev)148 static void ipc_wwan_setup(struct net_device *iosm_dev)
149 {
150 	iosm_dev->header_ops = NULL;
151 	iosm_dev->hard_header_len = 0;
152 	iosm_dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
153 
154 	iosm_dev->type = ARPHRD_NONE;
155 	iosm_dev->mtu = ETH_DATA_LEN;
156 	iosm_dev->min_mtu = ETH_MIN_MTU;
157 	iosm_dev->max_mtu = ETH_MAX_MTU;
158 
159 	iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;
160 	iosm_dev->needs_free_netdev = true;
161 
162 	iosm_dev->netdev_ops = &ipc_inm_ops;
163 }
164 
165 /* Create new wwan net link */
ipc_wwan_newlink(void * ctxt,struct net_device * dev,u32 if_id,struct netlink_ext_ack * extack)166 static int ipc_wwan_newlink(void *ctxt, struct net_device *dev,
167 			    u32 if_id, struct netlink_ext_ack *extack)
168 {
169 	struct iosm_wwan *ipc_wwan = ctxt;
170 	struct iosm_netdev_priv *priv;
171 	int err;
172 
173 	if (if_id < IP_MUX_SESSION_START ||
174 	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))
175 		return -EINVAL;
176 
177 	priv = wwan_netdev_drvpriv(dev);
178 	priv->if_id = if_id;
179 	priv->netdev = dev;
180 	priv->ipc_wwan = ipc_wwan;
181 
182 	if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id]))
183 		return -EBUSY;
184 
185 	err = register_netdevice(dev);
186 	if (err)
187 		return err;
188 
189 	rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);
190 	netif_device_attach(dev);
191 
192 	return 0;
193 }
194 
ipc_wwan_dellink(void * ctxt,struct net_device * dev,struct list_head * head)195 static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,
196 			     struct list_head *head)
197 {
198 	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(dev);
199 	struct iosm_wwan *ipc_wwan = ctxt;
200 	int if_id = priv->if_id;
201 
202 	if (WARN_ON(if_id < IP_MUX_SESSION_START ||
203 		    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))
204 		return;
205 
206 	if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))
207 		return;
208 
209 	RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);
210 	/* unregistering includes synchronize_net() */
211 	unregister_netdevice_queue(dev, head);
212 }
213 
214 static const struct wwan_ops iosm_wwan_ops = {
215 	.priv_size = sizeof(struct iosm_netdev_priv),
216 	.setup = ipc_wwan_setup,
217 	.newlink = ipc_wwan_newlink,
218 	.dellink = ipc_wwan_dellink,
219 };
220 
ipc_wwan_receive(struct iosm_wwan * ipc_wwan,struct sk_buff * skb_arg,bool dss,int if_id)221 int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,
222 		     bool dss, int if_id)
223 {
224 	struct sk_buff *skb = skb_arg;
225 	struct net_device_stats *stats;
226 	struct iosm_netdev_priv *priv;
227 	int ret;
228 
229 	if ((skb->data[0] & IOSM_IP_TYPE_MASK) == IOSM_IP_TYPE_IPV4)
230 		skb->protocol = htons(ETH_P_IP);
231 	else if ((skb->data[0] & IOSM_IP_TYPE_MASK) ==
232 		 IOSM_IP_TYPE_IPV6)
233 		skb->protocol = htons(ETH_P_IPV6);
234 
235 	skb->pkt_type = PACKET_HOST;
236 
237 	if (if_id < IP_MUX_SESSION_START ||
238 	    if_id > IP_MUX_SESSION_END) {
239 		ret = -EINVAL;
240 		goto free;
241 	}
242 
243 	rcu_read_lock();
244 	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
245 	if (!priv) {
246 		ret = -EINVAL;
247 		goto unlock;
248 	}
249 	skb->dev = priv->netdev;
250 	stats = &priv->netdev->stats;
251 	stats->rx_packets++;
252 	stats->rx_bytes += skb->len;
253 
254 	ret = netif_rx(skb);
255 	skb = NULL;
256 unlock:
257 	rcu_read_unlock();
258 free:
259 	dev_kfree_skb(skb);
260 	return ret;
261 }
262 
ipc_wwan_tx_flowctrl(struct iosm_wwan * ipc_wwan,int if_id,bool on)263 void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int if_id, bool on)
264 {
265 	struct net_device *netdev;
266 	struct iosm_netdev_priv *priv;
267 	bool is_tx_blk;
268 
269 	rcu_read_lock();
270 	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);
271 	if (!priv) {
272 		rcu_read_unlock();
273 		return;
274 	}
275 
276 	netdev = priv->netdev;
277 
278 	is_tx_blk = netif_queue_stopped(netdev);
279 
280 	if (on)
281 		dev_dbg(ipc_wwan->dev, "session id[%d]: flowctrl enable",
282 			if_id);
283 
284 	if (on && !is_tx_blk)
285 		netif_stop_queue(netdev);
286 	else if (!on && is_tx_blk)
287 		netif_wake_queue(netdev);
288 	rcu_read_unlock();
289 }
290 
ipc_wwan_init(struct iosm_imem * ipc_imem,struct device * dev)291 struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)
292 {
293 	struct iosm_wwan *ipc_wwan;
294 
295 	ipc_wwan = kzalloc(sizeof(*ipc_wwan), GFP_KERNEL);
296 	if (!ipc_wwan)
297 		return NULL;
298 
299 	ipc_wwan->dev = dev;
300 	ipc_wwan->ipc_imem = ipc_imem;
301 
302 	/* WWAN core will create a netdev for the default IP MUX channel */
303 	if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan,
304 			      IP_MUX_SESSION_DEFAULT)) {
305 		kfree(ipc_wwan);
306 		return NULL;
307 	}
308 
309 	return ipc_wwan;
310 }
311 
ipc_wwan_deinit(struct iosm_wwan * ipc_wwan)312 void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan)
313 {
314 	/* This call will remove all child netdev(s) */
315 	wwan_unregister_ops(ipc_wwan->dev);
316 
317 	kfree(ipc_wwan);
318 }
319