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 */
 28struct 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 */
 42struct 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 */
 49static 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 */
 79static 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 */
 93static 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
127exit:
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 */
139static 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 */
146static 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 */
164static 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
193static 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
212static 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
219int 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;
254unlock:
255	rcu_read_unlock();
256free:
257	dev_kfree_skb(skb);
258	return ret;
259}
260
261void 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
289struct 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
310void 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}