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 */
 30struct 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 */
 44struct 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 */
 51static 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 */
 81static 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 */
 95static 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
129exit:
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 */
141static 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 */
148static 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 */
166static 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
195static 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
214static 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
221int 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;
256unlock:
257	rcu_read_unlock();
258free:
259	dev_kfree_skb(skb);
260	return ret;
261}
262
263void 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
291struct 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
312void 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}