1/*
2 * This file is provided under a dual BSD/GPLv2 license.  When using or
3 *   redistributing this file, you may do so under either license.
4 *
5 *   GPL LICENSE SUMMARY
6 *
7 *   Copyright(c) 2012 Intel Corporation. All rights reserved.
8 *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
9 *
10 *   This program is free software; you can redistribute it and/or modify
11 *   it under the terms of version 2 of the GNU General Public License as
12 *   published by the Free Software Foundation.
13 *
14 *   BSD LICENSE
15 *
16 *   Copyright(c) 2012 Intel Corporation. All rights reserved.
17 *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
18 *
19 *   Redistribution and use in source and binary forms, with or without
20 *   modification, are permitted provided that the following conditions
21 *   are met:
22 *
23 *     * Redistributions of source code must retain the above copyright
24 *       notice, this list of conditions and the following disclaimer.
25 *     * Redistributions in binary form must reproduce the above copy
26 *       notice, this list of conditions and the following disclaimer in
27 *       the documentation and/or other materials provided with the
28 *       distribution.
29 *     * Neither the name of Intel Corporation nor the names of its
30 *       contributors may be used to endorse or promote products derived
31 *       from this software without specific prior written permission.
32 *
33 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
34 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
35 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
36 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
37 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
40 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
41 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
42 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
43 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 *
45 * PCIe NTB Network Linux driver
46 *
47 * Contact Information:
48 * Jon Mason <jon.mason@intel.com>
49 */
50#include <linux/etherdevice.h>
51#include <linux/ethtool.h>
52#include <linux/module.h>
53#include <linux/pci.h>
54#include <linux/ntb.h>
55#include <linux/ntb_transport.h>
56
57#define NTB_NETDEV_VER	"0.7"
58
59MODULE_DESCRIPTION(KBUILD_MODNAME);
60MODULE_VERSION(NTB_NETDEV_VER);
61MODULE_LICENSE("Dual BSD/GPL");
62MODULE_AUTHOR("Intel Corporation");
63
64/* Time in usecs for tx resource reaper */
65static unsigned int tx_time = 1;
66
67/* Number of descriptors to free before resuming tx */
68static unsigned int tx_start = 10;
69
70/* Number of descriptors still available before stop upper layer tx */
71static unsigned int tx_stop = 5;
72
73struct ntb_netdev {
74	struct list_head list;
75	struct pci_dev *pdev;
76	struct net_device *ndev;
77	struct ntb_transport_qp *qp;
78	struct timer_list tx_timer;
79};
80
81#define	NTB_TX_TIMEOUT_MS	1000
82#define	NTB_RXQ_SIZE		100
83
84static LIST_HEAD(dev_list);
85
86static void ntb_netdev_event_handler(void *data, int link_is_up)
87{
88	struct net_device *ndev = data;
89	struct ntb_netdev *dev = netdev_priv(ndev);
90
91	netdev_dbg(ndev, "Event %x, Link %x\n", link_is_up,
92		   ntb_transport_link_query(dev->qp));
93
94	if (link_is_up) {
95		if (ntb_transport_link_query(dev->qp))
96			netif_carrier_on(ndev);
97	} else {
98		netif_carrier_off(ndev);
99	}
100}
101
102static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
103				  void *data, int len)
104{
105	struct net_device *ndev = qp_data;
106	struct sk_buff *skb;
107	int rc;
108
109	skb = data;
110	if (!skb)
111		return;
112
113	netdev_dbg(ndev, "%s: %d byte payload received\n", __func__, len);
114
115	if (len < 0) {
116		ndev->stats.rx_errors++;
117		ndev->stats.rx_length_errors++;
118		goto enqueue_again;
119	}
120
121	skb_put(skb, len);
122	skb->protocol = eth_type_trans(skb, ndev);
123	skb->ip_summed = CHECKSUM_NONE;
124
125	if (netif_rx(skb) == NET_RX_DROP) {
126		ndev->stats.rx_errors++;
127		ndev->stats.rx_dropped++;
128	} else {
129		ndev->stats.rx_packets++;
130		ndev->stats.rx_bytes += len;
131	}
132
133	skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN);
134	if (!skb) {
135		ndev->stats.rx_errors++;
136		ndev->stats.rx_frame_errors++;
137		return;
138	}
139
140enqueue_again:
141	rc = ntb_transport_rx_enqueue(qp, skb, skb->data, ndev->mtu + ETH_HLEN);
142	if (rc) {
143		dev_kfree_skb(skb);
144		ndev->stats.rx_errors++;
145		ndev->stats.rx_fifo_errors++;
146	}
147}
148
149static int __ntb_netdev_maybe_stop_tx(struct net_device *netdev,
150				      struct ntb_transport_qp *qp, int size)
151{
152	struct ntb_netdev *dev = netdev_priv(netdev);
153
154	netif_stop_queue(netdev);
155	/* Make sure to see the latest value of ntb_transport_tx_free_entry()
156	 * since the queue was last started.
157	 */
158	smp_mb();
159
160	if (likely(ntb_transport_tx_free_entry(qp) < size)) {
161		mod_timer(&dev->tx_timer, jiffies + usecs_to_jiffies(tx_time));
162		return -EBUSY;
163	}
164
165	netif_start_queue(netdev);
166	return 0;
167}
168
169static int ntb_netdev_maybe_stop_tx(struct net_device *ndev,
170				    struct ntb_transport_qp *qp, int size)
171{
172	if (netif_queue_stopped(ndev) ||
173	    (ntb_transport_tx_free_entry(qp) >= size))
174		return 0;
175
176	return __ntb_netdev_maybe_stop_tx(ndev, qp, size);
177}
178
179static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
180				  void *data, int len)
181{
182	struct net_device *ndev = qp_data;
183	struct sk_buff *skb;
184	struct ntb_netdev *dev = netdev_priv(ndev);
185
186	skb = data;
187	if (!skb || !ndev)
188		return;
189
190	if (len > 0) {
191		ndev->stats.tx_packets++;
192		ndev->stats.tx_bytes += skb->len;
193	} else {
194		ndev->stats.tx_errors++;
195		ndev->stats.tx_aborted_errors++;
196	}
197
198	dev_kfree_skb(skb);
199
200	if (ntb_transport_tx_free_entry(dev->qp) >= tx_start) {
201		/* Make sure anybody stopping the queue after this sees the new
202		 * value of ntb_transport_tx_free_entry()
203		 */
204		smp_mb();
205		if (netif_queue_stopped(ndev))
206			netif_wake_queue(ndev);
207	}
208}
209
210static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
211					 struct net_device *ndev)
212{
213	struct ntb_netdev *dev = netdev_priv(ndev);
214	int rc;
215
216	ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
217
218	rc = ntb_transport_tx_enqueue(dev->qp, skb, skb->data, skb->len);
219	if (rc)
220		goto err;
221
222	/* check for next submit */
223	ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
224
225	return NETDEV_TX_OK;
226
227err:
228	ndev->stats.tx_dropped++;
229	ndev->stats.tx_errors++;
230	return NETDEV_TX_BUSY;
231}
232
233static void ntb_netdev_tx_timer(unsigned long data)
234{
235	struct net_device *ndev = (struct net_device *)data;
236	struct ntb_netdev *dev = netdev_priv(ndev);
237
238	if (ntb_transport_tx_free_entry(dev->qp) < tx_stop) {
239		mod_timer(&dev->tx_timer, jiffies + msecs_to_jiffies(tx_time));
240	} else {
241		/* Make sure anybody stopping the queue after this sees the new
242		 * value of ntb_transport_tx_free_entry()
243		 */
244		smp_mb();
245		if (netif_queue_stopped(ndev))
246			netif_wake_queue(ndev);
247	}
248}
249
250static int ntb_netdev_open(struct net_device *ndev)
251{
252	struct ntb_netdev *dev = netdev_priv(ndev);
253	struct sk_buff *skb;
254	int rc, i, len;
255
256	/* Add some empty rx bufs */
257	for (i = 0; i < NTB_RXQ_SIZE; i++) {
258		skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN);
259		if (!skb) {
260			rc = -ENOMEM;
261			goto err;
262		}
263
264		rc = ntb_transport_rx_enqueue(dev->qp, skb, skb->data,
265					      ndev->mtu + ETH_HLEN);
266		if (rc) {
267			dev_kfree_skb(skb);
268			goto err;
269		}
270	}
271
272	setup_timer(&dev->tx_timer, ntb_netdev_tx_timer, (unsigned long)ndev);
273
274	netif_carrier_off(ndev);
275	ntb_transport_link_up(dev->qp);
276	netif_start_queue(ndev);
277
278	return 0;
279
280err:
281	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
282		dev_kfree_skb(skb);
283	return rc;
284}
285
286static int ntb_netdev_close(struct net_device *ndev)
287{
288	struct ntb_netdev *dev = netdev_priv(ndev);
289	struct sk_buff *skb;
290	int len;
291
292	ntb_transport_link_down(dev->qp);
293
294	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
295		dev_kfree_skb(skb);
296
297	del_timer_sync(&dev->tx_timer);
298
299	return 0;
300}
301
302static int ntb_netdev_change_mtu(struct net_device *ndev, int new_mtu)
303{
304	struct ntb_netdev *dev = netdev_priv(ndev);
305	struct sk_buff *skb;
306	int len, rc;
307
308	if (new_mtu > ntb_transport_max_size(dev->qp) - ETH_HLEN)
309		return -EINVAL;
310
311	if (!netif_running(ndev)) {
312		ndev->mtu = new_mtu;
313		return 0;
314	}
315
316	/* Bring down the link and dispose of posted rx entries */
317	ntb_transport_link_down(dev->qp);
318
319	if (ndev->mtu < new_mtu) {
320		int i;
321
322		for (i = 0; (skb = ntb_transport_rx_remove(dev->qp, &len)); i++)
323			dev_kfree_skb(skb);
324
325		for (; i; i--) {
326			skb = netdev_alloc_skb(ndev, new_mtu + ETH_HLEN);
327			if (!skb) {
328				rc = -ENOMEM;
329				goto err;
330			}
331
332			rc = ntb_transport_rx_enqueue(dev->qp, skb, skb->data,
333						      new_mtu + ETH_HLEN);
334			if (rc) {
335				dev_kfree_skb(skb);
336				goto err;
337			}
338		}
339	}
340
341	ndev->mtu = new_mtu;
342
343	ntb_transport_link_up(dev->qp);
344
345	return 0;
346
347err:
348	ntb_transport_link_down(dev->qp);
349
350	while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
351		dev_kfree_skb(skb);
352
353	netdev_err(ndev, "Error changing MTU, device inoperable\n");
354	return rc;
355}
356
357static const struct net_device_ops ntb_netdev_ops = {
358	.ndo_open = ntb_netdev_open,
359	.ndo_stop = ntb_netdev_close,
360	.ndo_start_xmit = ntb_netdev_start_xmit,
361	.ndo_change_mtu = ntb_netdev_change_mtu,
362	.ndo_set_mac_address = eth_mac_addr,
363};
364
365static void ntb_get_drvinfo(struct net_device *ndev,
366			    struct ethtool_drvinfo *info)
367{
368	struct ntb_netdev *dev = netdev_priv(ndev);
369
370	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
371	strlcpy(info->version, NTB_NETDEV_VER, sizeof(info->version));
372	strlcpy(info->bus_info, pci_name(dev->pdev), sizeof(info->bus_info));
373}
374
375static int ntb_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
376{
377	cmd->supported = SUPPORTED_Backplane;
378	cmd->advertising = ADVERTISED_Backplane;
379	ethtool_cmd_speed_set(cmd, SPEED_UNKNOWN);
380	cmd->duplex = DUPLEX_FULL;
381	cmd->port = PORT_OTHER;
382	cmd->phy_address = 0;
383	cmd->transceiver = XCVR_DUMMY1;
384	cmd->autoneg = AUTONEG_ENABLE;
385	cmd->maxtxpkt = 0;
386	cmd->maxrxpkt = 0;
387
388	return 0;
389}
390
391static const struct ethtool_ops ntb_ethtool_ops = {
392	.get_drvinfo = ntb_get_drvinfo,
393	.get_link = ethtool_op_get_link,
394	.get_settings = ntb_get_settings,
395};
396
397static const struct ntb_queue_handlers ntb_netdev_handlers = {
398	.tx_handler = ntb_netdev_tx_handler,
399	.rx_handler = ntb_netdev_rx_handler,
400	.event_handler = ntb_netdev_event_handler,
401};
402
403static int ntb_netdev_probe(struct device *client_dev)
404{
405	struct ntb_dev *ntb;
406	struct net_device *ndev;
407	struct pci_dev *pdev;
408	struct ntb_netdev *dev;
409	int rc;
410
411	ntb = dev_ntb(client_dev->parent);
412	pdev = ntb->pdev;
413	if (!pdev)
414		return -ENODEV;
415
416	ndev = alloc_etherdev(sizeof(*dev));
417	if (!ndev)
418		return -ENOMEM;
419
420	dev = netdev_priv(ndev);
421	dev->ndev = ndev;
422	dev->pdev = pdev;
423	ndev->features = NETIF_F_HIGHDMA;
424
425	ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
426
427	ndev->hw_features = ndev->features;
428	ndev->watchdog_timeo = msecs_to_jiffies(NTB_TX_TIMEOUT_MS);
429
430	random_ether_addr(ndev->perm_addr);
431	memcpy(ndev->dev_addr, ndev->perm_addr, ndev->addr_len);
432
433	ndev->netdev_ops = &ntb_netdev_ops;
434	ndev->ethtool_ops = &ntb_ethtool_ops;
435
436	dev->qp = ntb_transport_create_queue(ndev, client_dev,
437					     &ntb_netdev_handlers);
438	if (!dev->qp) {
439		rc = -EIO;
440		goto err;
441	}
442
443	ndev->mtu = ntb_transport_max_size(dev->qp) - ETH_HLEN;
444
445	rc = register_netdev(ndev);
446	if (rc)
447		goto err1;
448
449	list_add(&dev->list, &dev_list);
450	dev_info(&pdev->dev, "%s created\n", ndev->name);
451	return 0;
452
453err1:
454	ntb_transport_free_queue(dev->qp);
455err:
456	free_netdev(ndev);
457	return rc;
458}
459
460static void ntb_netdev_remove(struct device *client_dev)
461{
462	struct ntb_dev *ntb;
463	struct net_device *ndev;
464	struct pci_dev *pdev;
465	struct ntb_netdev *dev;
466	bool found = false;
467
468	ntb = dev_ntb(client_dev->parent);
469	pdev = ntb->pdev;
470
471	list_for_each_entry(dev, &dev_list, list) {
472		if (dev->pdev == pdev) {
473			found = true;
474			break;
475		}
476	}
477	if (!found)
478		return;
479
480	list_del(&dev->list);
481
482	ndev = dev->ndev;
483
484	unregister_netdev(ndev);
485	ntb_transport_free_queue(dev->qp);
486	free_netdev(ndev);
487}
488
489static struct ntb_transport_client ntb_netdev_client = {
490	.driver.name = KBUILD_MODNAME,
491	.driver.owner = THIS_MODULE,
492	.probe = ntb_netdev_probe,
493	.remove = ntb_netdev_remove,
494};
495
496static int __init ntb_netdev_init_module(void)
497{
498	int rc;
499
500	rc = ntb_transport_register_client_dev(KBUILD_MODNAME);
501	if (rc)
502		return rc;
503	return ntb_transport_register_client(&ntb_netdev_client);
504}
505module_init(ntb_netdev_init_module);
506
507static void __exit ntb_netdev_exit_module(void)
508{
509	ntb_transport_unregister_client(&ntb_netdev_client);
510	ntb_transport_unregister_client_dev(KBUILD_MODNAME);
511}
512module_exit(ntb_netdev_exit_module);
513