[mirror_ubuntu-jammy-kernel.git] / net / caif / caif_dev.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * CAIF Interface registration.
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 *
 * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
 *  and Sakari Ailus <sakari.ailus@nokia.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <net/netns/generic.h>
#include <net/net_namespace.h>
#include <net/pkt_sched.h>
#include <net/caif/caif_device.h>
#include <net/caif/caif_layer.h>
#include <net/caif/caif_dev.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfcnfg.h>
#include <net/caif/cfserl.h>

MODULE_LICENSE("GPL");

/* Used for local tracking of the CAIF net devices */
struct caif_device_entry {
	struct cflayer layer;
	struct list_head list;
	struct net_device *netdev;
	int __percpu *pcpu_refcnt;
	spinlock_t flow_lock;
	struct sk_buff *xoff_skb;
	void (*xoff_skb_dtor)(struct sk_buff *skb);
	bool xoff;
};

struct caif_device_entry_list {
	struct list_head list;
	/* Protects simulanous deletes in list */
	struct mutex lock;
};

struct caif_net {
	struct cfcnfg *cfg;
	struct caif_device_entry_list caifdevs;
};

static unsigned int caif_net_id;
static int q_high = 50; /* Percent */

struct cfcnfg *get_cfcnfg(struct net *net)
{
	struct caif_net *caifn;
	caifn = net_generic(net, caif_net_id);
	return caifn->cfg;
}
EXPORT_SYMBOL(get_cfcnfg);

static struct caif_device_entry_list *caif_device_list(struct net *net)
{
	struct caif_net *caifn;
	caifn = net_generic(net, caif_net_id);
	return &caifn->caifdevs;
}

static void caifd_put(struct caif_device_entry *e)
{
	this_cpu_dec(*e->pcpu_refcnt);
}

static void caifd_hold(struct caif_device_entry *e)
{
	this_cpu_inc(*e->pcpu_refcnt);
}

static int caifd_refcnt_read(struct caif_device_entry *e)
{
	int i, refcnt = 0;
	for_each_possible_cpu(i)
		refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
	return refcnt;
}

/* Allocate new CAIF device. */
static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
{
	struct caif_device_entry *caifd;

	caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
	if (!caifd)
		return NULL;
	caifd->pcpu_refcnt = alloc_percpu(int);
	if (!caifd->pcpu_refcnt) {
		kfree(caifd);
		return NULL;
	}
	caifd->netdev = dev;
	dev_hold(dev);
	return caifd;
}

static struct caif_device_entry *caif_get(struct net_device *dev)
{
	struct caif_device_entry_list *caifdevs =
	    caif_device_list(dev_net(dev));
	struct caif_device_entry *caifd;

	list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
		if (caifd->netdev == dev)
			return caifd;
	}
	return NULL;
}

static void caif_flow_cb(struct sk_buff *skb)
{
	struct caif_device_entry *caifd;
	void (*dtor)(struct sk_buff *skb) = NULL;
	bool send_xoff;

	WARN_ON(skb->dev == NULL);

	rcu_read_lock();
	caifd = caif_get(skb->dev);

	WARN_ON(caifd == NULL);
	if (!caifd) {
		rcu_read_unlock();
		return;
	}

	caifd_hold(caifd);
	rcu_read_unlock();

	spin_lock_bh(&caifd->flow_lock);
	send_xoff = caifd->xoff;
	caifd->xoff = 0;
	dtor = caifd->xoff_skb_dtor;

	if (WARN_ON(caifd->xoff_skb != skb))
		skb = NULL;

	caifd->xoff_skb = NULL;
	caifd->xoff_skb_dtor = NULL;

	spin_unlock_bh(&caifd->flow_lock);

	if (dtor && skb)
		dtor(skb);

	if (send_xoff)
		caifd->layer.up->
			ctrlcmd(caifd->layer.up,
				_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
				caifd->layer.id);
	caifd_put(caifd);
}

static int transmit(struct cflayer *layer, struct cfpkt *pkt)
{
	int err, high = 0, qlen = 0;
	struct caif_device_entry *caifd =
	    container_of(layer, struct caif_device_entry, layer);
	struct sk_buff *skb;
	struct netdev_queue *txq;

	rcu_read_lock_bh();

	skb = cfpkt_tonative(pkt);
	skb->dev = caifd->netdev;
	skb_reset_network_header(skb);
	skb->protocol = htons(ETH_P_CAIF);

	/* Check if we need to handle xoff */
	if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
		goto noxoff;

	if (unlikely(caifd->xoff))
		goto noxoff;

	if (likely(!netif_queue_stopped(caifd->netdev))) {
		struct Qdisc *sch;

		/* If we run with a TX queue, check if the queue is too long*/
		txq = netdev_get_tx_queue(skb->dev, 0);
		sch = rcu_dereference_bh(txq->qdisc);
		if (likely(qdisc_is_empty(sch)))
			goto noxoff;

		/* can check for explicit qdisc len value only !NOLOCK,
		 * always set flow off otherwise
		 */
		high = (caifd->netdev->tx_queue_len * q_high) / 100;
		if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
			goto noxoff;
	}

	/* Hold lock while accessing xoff */
	spin_lock_bh(&caifd->flow_lock);
	if (caifd->xoff) {
		spin_unlock_bh(&caifd->flow_lock);
		goto noxoff;
	}

	/*
	 * Handle flow off, we do this by temporary hi-jacking this
	 * skb's destructor function, and replace it with our own
	 * flow-on callback. The callback will set flow-on and call
	 * the original destructor.
	 */

	pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
			netif_queue_stopped(caifd->netdev),
			qlen, high);
	caifd->xoff = 1;
	caifd->xoff_skb = skb;
	caifd->xoff_skb_dtor = skb->destructor;
	skb->destructor = caif_flow_cb;
	spin_unlock_bh(&caifd->flow_lock);

	caifd->layer.up->ctrlcmd(caifd->layer.up,
					_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
					caifd->layer.id);
noxoff:
	rcu_read_unlock_bh();

	err = dev_queue_xmit(skb);
	if (err > 0)
		err = -EIO;

	return err;
}

/*
 * Stuff received packets into the CAIF stack.
 * On error, returns non-zero and releases the skb.
 */
static int receive(struct sk_buff *skb, struct net_device *dev,
		   struct packet_type *pkttype, struct net_device *orig_dev)
{
	struct cfpkt *pkt;
	struct caif_device_entry *caifd;
	int err;

	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);

	rcu_read_lock();
	caifd = caif_get(dev);

	if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
			!netif_oper_up(caifd->netdev)) {
		rcu_read_unlock();
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	/* Hold reference to netdevice while using CAIF stack */
	caifd_hold(caifd);
	rcu_read_unlock();

	err = caifd->layer.up->receive(caifd->layer.up, pkt);

	/* For -EILSEQ the packet is not freed so so it now */
	if (err == -EILSEQ)
		cfpkt_destroy(pkt);

	/* Release reference to stack upwards */
	caifd_put(caifd);

	if (err != 0)
		err = NET_RX_DROP;
	return err;
}

static struct packet_type caif_packet_type __read_mostly = {
	.type = cpu_to_be16(ETH_P_CAIF),
	.func = receive,
};

static void dev_flowctrl(struct net_device *dev, int on)
{
	struct caif_device_entry *caifd;

	rcu_read_lock();

	caifd = caif_get(dev);
	if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
		rcu_read_unlock();
		return;
	}

	caifd_hold(caifd);
	rcu_read_unlock();

	caifd->layer.up->ctrlcmd(caifd->layer.up,
				 on ?
				 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
				 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
				 caifd->layer.id);
	caifd_put(caifd);
}

void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
		     struct cflayer *link_support, int head_room,
		     struct cflayer **layer,
		     int (**rcv_func)(struct sk_buff *, struct net_device *,
				      struct packet_type *,
				      struct net_device *))
{
	struct caif_device_entry *caifd;
	enum cfcnfg_phy_preference pref;
	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
	struct caif_device_entry_list *caifdevs;

	caifdevs = caif_device_list(dev_net(dev));
	caifd = caif_device_alloc(dev);
	if (!caifd)
		return;
	*layer = &caifd->layer;
	spin_lock_init(&caifd->flow_lock);

	switch (caifdev->link_select) {
	case CAIF_LINK_HIGH_BANDW:
		pref = CFPHYPREF_HIGH_BW;
		break;
	case CAIF_LINK_LOW_LATENCY:
		pref = CFPHYPREF_LOW_LAT;
		break;
	default:
		pref = CFPHYPREF_HIGH_BW;
		break;
	}
	mutex_lock(&caifdevs->lock);
	list_add_rcu(&caifd->list, &caifdevs->list);

	strlcpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name));
	caifd->layer.transmit = transmit;
	cfcnfg_add_phy_layer(cfg,
				dev,
				&caifd->layer,
				pref,
				link_support,
				caifdev->use_fcs,
				head_room);
	mutex_unlock(&caifdevs->lock);
	if (rcv_func)
		*rcv_func = receive;
}
EXPORT_SYMBOL(caif_enroll_dev);

/* notify Caif of device events */
static int caif_device_notify(struct notifier_block *me, unsigned long what,
			      void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct caif_device_entry *caifd = NULL;
	struct caif_dev_common *caifdev;
	struct cfcnfg *cfg;
	struct cflayer *layer, *link_support;
	int head_room = 0;
	struct caif_device_entry_list *caifdevs;

	cfg = get_cfcnfg(dev_net(dev));
	caifdevs = caif_device_list(dev_net(dev));

	caifd = caif_get(dev);
	if (caifd == NULL && dev->type != ARPHRD_CAIF)
		return 0;

	switch (what) {
	case NETDEV_REGISTER:
		if (caifd != NULL)
			break;

		caifdev = netdev_priv(dev);

		link_support = NULL;
		if (caifdev->use_frag) {
			head_room = 1;
			link_support = cfserl_create(dev->ifindex,
							caifdev->use_stx);
			if (!link_support) {
				pr_warn("Out of memory\n");
				break;
			}
		}
		caif_enroll_dev(dev, caifdev, link_support, head_room,
				&layer, NULL);
		caifdev->flowctrl = dev_flowctrl;
		break;

	case NETDEV_UP:
		rcu_read_lock();

		caifd = caif_get(dev);
		if (caifd == NULL) {
			rcu_read_unlock();
			break;
		}

		caifd->xoff = 0;
		cfcnfg_set_phy_state(cfg, &caifd->layer, true);
		rcu_read_unlock();

		break;

	case NETDEV_DOWN:
		rcu_read_lock();

		caifd = caif_get(dev);
		if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
			rcu_read_unlock();
			return -EINVAL;
		}

		cfcnfg_set_phy_state(cfg, &caifd->layer, false);
		caifd_hold(caifd);
		rcu_read_unlock();

		caifd->layer.up->ctrlcmd(caifd->layer.up,
					 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
					 caifd->layer.id);

		spin_lock_bh(&caifd->flow_lock);

		/*
		 * Replace our xoff-destructor with original destructor.
		 * We trust that skb->destructor *always* is called before
		 * the skb reference is invalid. The hijacked SKB destructor
		 * takes the flow_lock so manipulating the skb->destructor here
		 * should be safe.
		*/
		if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
			caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;

		caifd->xoff = 0;
		caifd->xoff_skb_dtor = NULL;
		caifd->xoff_skb = NULL;

		spin_unlock_bh(&caifd->flow_lock);
		caifd_put(caifd);
		break;

	case NETDEV_UNREGISTER:
		mutex_lock(&caifdevs->lock);

		caifd = caif_get(dev);
		if (caifd == NULL) {
			mutex_unlock(&caifdevs->lock);
			break;
		}
		list_del_rcu(&caifd->list);

		/*
		 * NETDEV_UNREGISTER is called repeatedly until all reference
		 * counts for the net-device are released. If references to
		 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
		 * the next call to NETDEV_UNREGISTER.
		 *
		 * If any packets are in flight down the CAIF Stack,
		 * cfcnfg_del_phy_layer will return nonzero.
		 * If no packets are in flight, the CAIF Stack associated
		 * with the net-device un-registering is freed.
		 */

		if (caifd_refcnt_read(caifd) != 0 ||
			cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {

			pr_info("Wait for device inuse\n");
			/* Enrole device if CAIF Stack is still in use */
			list_add_rcu(&caifd->list, &caifdevs->list);
			mutex_unlock(&caifdevs->lock);
			break;
		}

		synchronize_rcu();
		dev_put(caifd->netdev);
		free_percpu(caifd->pcpu_refcnt);
		kfree(caifd);

		mutex_unlock(&caifdevs->lock);
		break;
	}
	return 0;
}

static struct notifier_block caif_device_notifier = {
	.notifier_call = caif_device_notify,
	.priority = 0,
};

/* Per-namespace Caif devices handling */
static int caif_init_net(struct net *net)
{
	struct caif_net *caifn = net_generic(net, caif_net_id);
	INIT_LIST_HEAD(&caifn->caifdevs.list);
	mutex_init(&caifn->caifdevs.lock);

	caifn->cfg = cfcnfg_create();
	if (!caifn->cfg)
		return -ENOMEM;

	return 0;
}

static void caif_exit_net(struct net *net)
{
	struct caif_device_entry *caifd, *tmp;
	struct caif_device_entry_list *caifdevs =
	    caif_device_list(net);
	struct cfcnfg *cfg =  get_cfcnfg(net);

	rtnl_lock();
	mutex_lock(&caifdevs->lock);

	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
		int i = 0;
		list_del_rcu(&caifd->list);
		cfcnfg_set_phy_state(cfg, &caifd->layer, false);

		while (i < 10 &&
			(caifd_refcnt_read(caifd) != 0 ||
			cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {

			pr_info("Wait for device inuse\n");
			msleep(250);
			i++;
		}
		synchronize_rcu();
		dev_put(caifd->netdev);
		free_percpu(caifd->pcpu_refcnt);
		kfree(caifd);
	}
	cfcnfg_remove(cfg);

	mutex_unlock(&caifdevs->lock);
	rtnl_unlock();
}

static struct pernet_operations caif_net_ops = {
	.init = caif_init_net,
	.exit = caif_exit_net,
	.id   = &caif_net_id,
	.size = sizeof(struct caif_net),
};

/* Initialize Caif devices list */
static int __init caif_device_init(void)
{
	int result;

	result = register_pernet_subsys(&caif_net_ops);

	if (result)
		return result;

	register_netdevice_notifier(&caif_device_notifier);
	dev_add_pack(&caif_packet_type);

	return result;
}

static void __exit caif_device_exit(void)
{
	unregister_netdevice_notifier(&caif_device_notifier);
	dev_remove_pack(&caif_packet_type);
	unregister_pernet_subsys(&caif_net_ops);
}

module_init(caif_device_init);
module_exit(caif_device_exit);
Commit	Line	Data
af873fce	1	// SPDX-License-Identifier: GPL-2.0-only
c72dfae2 SB	2	/*
	3	* CAIF Interface registration.
	4	* Copyright (C) ST-Ericsson AB 2010
26ee65e6	5	* Author: Sjur Brendeland
c72dfae2	6	*
31fdc555	7	* Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
c72dfae2 SB	8	* and Sakari Ailus <sakari.ailus@nokia.com>
	9	*/
	10
b31fa5ba JP	11	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
b31fa5ba JP	12
c72dfae2 SB	13	#include <linux/kernel.h>
	14	#include <linux/if_arp.h>
	15	#include <linux/net.h>
	16	#include <linux/netdevice.h>
bd30ce4b	17	#include <linux/mutex.h>
3a9a231d	18	#include <linux/module.h>
0e4c7d85	19	#include <linux/spinlock.h>
c72dfae2 SB	20	#include <net/netns/generic.h>
	21	#include <net/net_namespace.h>
	22	#include <net/pkt_sched.h>
	23	#include <net/caif/caif_device.h>
c72dfae2	24	#include <net/caif/caif_layer.h>
8203274e	25	#include <net/caif/caif_dev.h>
c72dfae2 SB	26	#include <net/caif/cfpkt.h>
c72dfae2 SB	27	#include <net/caif/cfcnfg.h>
7c18d220	28	#include <net/caif/cfserl.h>
c72dfae2 SB	29
c72dfae2 SB	30	MODULE_LICENSE("GPL");
c72dfae2 SB	31
	32	/* Used for local tracking of the CAIF net devices */
	33	struct caif_device_entry {
	34	struct cflayer layer;
	35	struct list_head list;
c72dfae2	36	struct net_device *netdev;
bd30ce4b	37	int __percpu *pcpu_refcnt;
0e4c7d85	38	spinlock_t flow_lock;
7d311304	39	struct sk_buff *xoff_skb;
7d311304	40	void (xoff_skb_dtor)(struct sk_buff skb);
0e4c7d85	41	bool xoff;
c72dfae2 SB	42	};
	43
	44	struct caif_device_entry_list {
	45	struct list_head list;
	46	/* Protects simulanous deletes in list */
bd30ce4b	47	struct mutex lock;
c72dfae2 SB	48	};
	49
	50	struct caif_net {
bee925db	51	struct cfcnfg *cfg;
c72dfae2 SB	52	struct caif_device_entry_list caifdevs;
	53	};
	54
c7d03a00	55	static unsigned int caif_net_id;
0e4c7d85	56	static int q_high = 50; /* Percent */
bee925db	57
	58	struct cfcnfg get_cfcnfg(struct net net)
	59	{
	60	struct caif_net *caifn;
bee925db	61	caifn = net_generic(net, caif_net_id);
bee925db	62	return caifn->cfg;
	63	}
	64	EXPORT_SYMBOL(get_cfcnfg);
c72dfae2 SB	65
	66	static struct caif_device_entry_list caif_device_list(struct net net)
	67	{
	68	struct caif_net *caifn;
c72dfae2	69	caifn = net_generic(net, caif_net_id);
c72dfae2 SB	70	return &caifn->caifdevs;
	71	}
	72
bd30ce4b	73	static void caifd_put(struct caif_device_entry *e)
bd30ce4b	74	{
933393f5	75	this_cpu_dec(*e->pcpu_refcnt);
bd30ce4b	76	}
	77
	78	static void caifd_hold(struct caif_device_entry *e)
	79	{
933393f5	80	this_cpu_inc(*e->pcpu_refcnt);
bd30ce4b	81	}
	82
	83	static int caifd_refcnt_read(struct caif_device_entry *e)
	84	{
	85	int i, refcnt = 0;
	86	for_each_possible_cpu(i)
	87	refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
	88	return refcnt;
	89	}
	90
c72dfae2 SB	91	/* Allocate new CAIF device. */
	92	static struct caif_device_entry caif_device_alloc(struct net_device dev)
	93	{
c72dfae2	94	struct caif_device_entry *caifd;
bd30ce4b	95
4fb66b82	96	caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
c72dfae2 SB	97	if (!caifd)
c72dfae2 SB	98	return NULL;
bd30ce4b	99	caifd->pcpu_refcnt = alloc_percpu(int);
4fb66b82 ED	100	if (!caifd->pcpu_refcnt) {
	101	kfree(caifd);
	102	return NULL;
	103	}
c72dfae2	104	caifd->netdev = dev;
bd30ce4b	105	dev_hold(dev);
c72dfae2 SB	106	return caifd;
	107	}
	108
	109	static struct caif_device_entry caif_get(struct net_device dev)
	110	{
	111	struct caif_device_entry_list *caifdevs =
	112	caif_device_list(dev_net(dev));
	113	struct caif_device_entry *caifd;
7c18d220	114
bd30ce4b	115	list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
c72dfae2 SB	116	if (caifd->netdev == dev)
	117	return caifd;
	118	}
	119	return NULL;
	120	}
	121
d6e89c0b	122	static void caif_flow_cb(struct sk_buff *skb)
0e4c7d85	123	{
0e4c7d85	124	struct caif_device_entry *caifd;
7d311304	125	void (dtor)(struct sk_buff skb) = NULL;
0e4c7d85	126	bool send_xoff;
	127
	128	WARN_ON(skb->dev == NULL);
	129
	130	rcu_read_lock();
	131	caifd = caif_get(skb->dev);
c95567c8 KLX	132
c95567c8 KLX	133	WARN_ON(caifd == NULL);
64119e05 Y	134	if (!caifd) {
64119e05 Y	135	rcu_read_unlock();
c95567c8	136	return;
64119e05	137	}
c95567c8	138
0e4c7d85	139	caifd_hold(caifd);
	140	rcu_read_unlock();
	141
	142	spin_lock_bh(&caifd->flow_lock);
	143	send_xoff = caifd->xoff;
	144	caifd->xoff = 0;
59f608d8	145	dtor = caifd->xoff_skb_dtor;
	146
	147	if (WARN_ON(caifd->xoff_skb != skb))
	148	skb = NULL;
	149
	150	caifd->xoff_skb = NULL;
	151	caifd->xoff_skb_dtor = NULL;
	152
0e4c7d85	153	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	154
59f608d8	155	if (dtor && skb)
7d311304	156	dtor(skb);
7d311304	157
0e4c7d85	158	if (send_xoff)
	159	caifd->layer.up->
	160	ctrlcmd(caifd->layer.up,
	161	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
	162	caifd->layer.id);
	163	caifd_put(caifd);
	164	}
	165
c72dfae2 SB	166	static int transmit(struct cflayer layer, struct cfpkt pkt)
c72dfae2 SB	167	{
0e4c7d85	168	int err, high = 0, qlen = 0;
c72dfae2 SB	169	struct caif_device_entry *caifd =
c72dfae2 SB	170	container_of(layer, struct caif_device_entry, layer);
4dd820c0	171	struct sk_buff *skb;
0e4c7d85	172	struct netdev_queue *txq;
	173
	174	rcu_read_lock_bh();
4dd820c0	175
c72dfae2 SB	176	skb = cfpkt_tonative(pkt);
c72dfae2 SB	177	skb->dev = caifd->netdev;
7c18d220	178	skb_reset_network_header(skb);
7c18d220	179	skb->protocol = htons(ETH_P_CAIF);
0e4c7d85	180
0e4c7d85	181	/* Check if we need to handle xoff */
4676a152	182	if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
0e4c7d85	183	goto noxoff;
	184
	185	if (unlikely(caifd->xoff))
	186	goto noxoff;
	187
	188	if (likely(!netif_queue_stopped(caifd->netdev))) {
b0a231a2 PA	189	struct Qdisc *sch;
b0a231a2 PA	190
0e4c7d85	191	/* If we run with a TX queue, check if the queue is too long*/
0e4c7d85	192	txq = netdev_get_tx_queue(skb->dev, 0);
b0a231a2 PA	193	sch = rcu_dereference_bh(txq->qdisc);
b0a231a2 PA	194	if (likely(qdisc_is_empty(sch)))
0e4c7d85	195	goto noxoff;
0e4c7d85	196
b0a231a2 PA	197	/* can check for explicit qdisc len value only !NOLOCK,
	198	* always set flow off otherwise
	199	*/
0e4c7d85	200	high = (caifd->netdev->tx_queue_len * q_high) / 100;
b0a231a2	201	if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
0e4c7d85	202	goto noxoff;
	203	}
	204
	205	/* Hold lock while accessing xoff */
	206	spin_lock_bh(&caifd->flow_lock);
	207	if (caifd->xoff) {
	208	spin_unlock_bh(&caifd->flow_lock);
	209	goto noxoff;
	210	}
	211
	212	/*
	213	* Handle flow off, we do this by temporary hi-jacking this
	214	* skb's destructor function, and replace it with our own
	215	* flow-on callback. The callback will set flow-on and call
	216	* the original destructor.
	217	*/
	218
	219	pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
	220	netif_queue_stopped(caifd->netdev),
	221	qlen, high);
	222	caifd->xoff = 1;
7d311304	223	caifd->xoff_skb = skb;
	224	caifd->xoff_skb_dtor = skb->destructor;
	225	skb->destructor = caif_flow_cb;
0e4c7d85	226	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	227
	228	caifd->layer.up->ctrlcmd(caifd->layer.up,
	229	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	230	caifd->layer.id);
	231	noxoff:
	232	rcu_read_unlock_bh();
4dd820c0	233
c85c2951	234	err = dev_queue_xmit(skb);
	235	if (err > 0)
	236	err = -EIO;
c72dfae2	237
c85c2951	238	return err;
c72dfae2 SB	239	}
c72dfae2 SB	240
c72dfae2	241	/*
bd30ce4b	242	* Stuff received packets into the CAIF stack.
c72dfae2 SB	243	* On error, returns non-zero and releases the skb.
	244	*/
	245	static int receive(struct sk_buff skb, struct net_device dev,
	246	struct packet_type pkttype, struct net_device orig_dev)
	247	{
c72dfae2 SB	248	struct cfpkt *pkt;
c72dfae2 SB	249	struct caif_device_entry *caifd;
69c867c9	250	int err;
bd30ce4b	251
c72dfae2	252	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
bd30ce4b	253
bd30ce4b	254	rcu_read_lock();
c72dfae2	255	caifd = caif_get(dev);
c72dfae2	256
bd30ce4b	257	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->receive \|\|
	258	!netif_oper_up(caifd->netdev)) {
	259	rcu_read_unlock();
	260	kfree_skb(skb);
c72dfae2	261	return NET_RX_DROP;
bd30ce4b	262	}
	263
	264	/* Hold reference to netdevice while using CAIF stack */
	265	caifd_hold(caifd);
	266	rcu_read_unlock();
c72dfae2	267
69c867c9	268	err = caifd->layer.up->receive(caifd->layer.up, pkt);
	269
	270	/* For -EILSEQ the packet is not freed so so it now */
	271	if (err == -EILSEQ)
	272	cfpkt_destroy(pkt);
bd30ce4b	273
	274	/* Release reference to stack upwards */
	275	caifd_put(caifd);
7c18d220	276
	277	if (err != 0)
	278	err = NET_RX_DROP;
	279	return err;
c72dfae2 SB	280	}
	281
	282	static struct packet_type caif_packet_type __read_mostly = {
	283	.type = cpu_to_be16(ETH_P_CAIF),
	284	.func = receive,
	285	};
	286
	287	static void dev_flowctrl(struct net_device *dev, int on)
	288	{
bd30ce4b	289	struct caif_device_entry *caifd;
	290
	291	rcu_read_lock();
	292
	293	caifd = caif_get(dev);
	294	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	295	rcu_read_unlock();
c72dfae2	296	return;
bd30ce4b	297	}
	298
	299	caifd_hold(caifd);
	300	rcu_read_unlock();
c72dfae2 SB	301
	302	caifd->layer.up->ctrlcmd(caifd->layer.up,
	303	on ?
	304	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
	305	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	306	caifd->layer.id);
bd30ce4b	307	caifd_put(caifd);
c72dfae2 SB	308	}
c72dfae2 SB	309
7c18d220	310	void caif_enroll_dev(struct net_device dev, struct caif_dev_common caifdev,
3bffc475 SMP	311	struct cflayer *link_support, int head_room,
	312	struct cflayer **layer,
	313	int (*rcv_func)(struct sk_buff , struct net_device *,
	314	struct packet_type *,
	315	struct net_device *))
7c18d220	316	{
	317	struct caif_device_entry *caifd;
	318	enum cfcnfg_phy_preference pref;
	319	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
	320	struct caif_device_entry_list *caifdevs;
	321
	322	caifdevs = caif_device_list(dev_net(dev));
7c18d220	323	caifd = caif_device_alloc(dev);
	324	if (!caifd)
	325	return;
	326	*layer = &caifd->layer;
0e4c7d85	327	spin_lock_init(&caifd->flow_lock);
7c18d220	328
	329	switch (caifdev->link_select) {
	330	case CAIF_LINK_HIGH_BANDW:
	331	pref = CFPHYPREF_HIGH_BW;
	332	break;
	333	case CAIF_LINK_LOW_LATENCY:
	334	pref = CFPHYPREF_LOW_LAT;
	335	break;
	336	default:
	337	pref = CFPHYPREF_HIGH_BW;
	338	break;
	339	}
	340	mutex_lock(&caifdevs->lock);
	341	list_add_rcu(&caifd->list, &caifdevs->list);
	342
3dc2fa47 XW	343	strlcpy(caifd->layer.name, dev->name,
3dc2fa47 XW	344	sizeof(caifd->layer.name));
7c18d220	345	caifd->layer.transmit = transmit;
	346	cfcnfg_add_phy_layer(cfg,
	347	dev,
	348	&caifd->layer,
	349	pref,
	350	link_support,
	351	caifdev->use_fcs,
	352	head_room);
	353	mutex_unlock(&caifdevs->lock);
	354	if (rcv_func)
	355	*rcv_func = receive;
	356	}
7ad65bf6	357	EXPORT_SYMBOL(caif_enroll_dev);
7c18d220	358
c72dfae2 SB	359	/* notify Caif of device events */
c72dfae2 SB	360	static int caif_device_notify(struct notifier_block *me, unsigned long what,
351638e7	361	void *ptr)
c72dfae2	362	{
351638e7	363	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
c72dfae2 SB	364	struct caif_device_entry *caifd = NULL;
c72dfae2 SB	365	struct caif_dev_common *caifdev;
bee925db	366	struct cfcnfg *cfg;
7c18d220	367	struct cflayer layer, link_support;
7c18d220	368	int head_room = 0;
08613e46	369	struct caif_device_entry_list *caifdevs;
c72dfae2	370
bee925db	371	cfg = get_cfcnfg(dev_net(dev));
7c18d220	372	caifdevs = caif_device_list(dev_net(dev));
bee925db	373
7c18d220	374	caifd = caif_get(dev);
	375	if (caifd == NULL && dev->type != ARPHRD_CAIF)
	376	return 0;
08613e46	377
c72dfae2 SB	378	switch (what) {
c72dfae2 SB	379	case NETDEV_REGISTER:
7c18d220	380	if (caifd != NULL)
7c18d220	381	break;
bd30ce4b	382
c72dfae2	383	caifdev = netdev_priv(dev);
c72dfae2	384
7c18d220	385	link_support = NULL;
	386	if (caifdev->use_frag) {
	387	head_room = 1;
	388	link_support = cfserl_create(dev->ifindex,
e977b4cf	389	caifdev->use_stx);
7c18d220	390	if (!link_support) {
	391	pr_warn("Out of memory\n");
	392	break;
	393	}
c72dfae2	394	}
7c18d220	395	caif_enroll_dev(dev, caifdev, link_support, head_room,
	396	&layer, NULL);
	397	caifdev->flowctrl = dev_flowctrl;
c72dfae2 SB	398	break;
c72dfae2 SB	399
bd30ce4b	400	case NETDEV_UP:
	401	rcu_read_lock();
	402
c72dfae2	403	caifd = caif_get(dev);
bd30ce4b	404	if (caifd == NULL) {
bd30ce4b	405	rcu_read_unlock();
c72dfae2	406	break;
bd30ce4b	407	}
c72dfae2	408
0e4c7d85	409	caifd->xoff = 0;
bd30ce4b	410	cfcnfg_set_phy_state(cfg, &caifd->layer, true);
bd30ce4b	411	rcu_read_unlock();
c72dfae2	412
c72dfae2 SB	413	break;
	414
	415	case NETDEV_DOWN:
bd30ce4b	416	rcu_read_lock();
bd30ce4b	417
c72dfae2	418	caifd = caif_get(dev);
bd30ce4b	419	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	420	rcu_read_unlock();
	421	return -EINVAL;
	422	}
	423
	424	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	425	caifd_hold(caifd);
	426	rcu_read_unlock();
	427
	428	caifd->layer.up->ctrlcmd(caifd->layer.up,
	429	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
	430	caifd->layer.id);
7d311304	431
	432	spin_lock_bh(&caifd->flow_lock);
	433
	434	/*
	435	* Replace our xoff-destructor with original destructor.
	436	* We trust that skb->destructor always is called before
	437	* the skb reference is invalid. The hijacked SKB destructor
	438	* takes the flow_lock so manipulating the skb->destructor here
	439	* should be safe.
	440	*/
	441	if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
	442	caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
	443
	444	caifd->xoff = 0;
	445	caifd->xoff_skb_dtor = NULL;
	446	caifd->xoff_skb = NULL;
	447
	448	spin_unlock_bh(&caifd->flow_lock);
bd30ce4b	449	caifd_put(caifd);
c72dfae2 SB	450	break;
	451
	452	case NETDEV_UNREGISTER:
bd30ce4b	453	mutex_lock(&caifdevs->lock);
bd30ce4b	454
c72dfae2	455	caifd = caif_get(dev);
bd30ce4b	456	if (caifd == NULL) {
bd30ce4b	457	mutex_unlock(&caifdevs->lock);
f2527ec4	458	break;
bd30ce4b	459	}
	460	list_del_rcu(&caifd->list);
	461
	462	/*
	463	* NETDEV_UNREGISTER is called repeatedly until all reference
	464	* counts for the net-device are released. If references to
	465	* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
	466	* the next call to NETDEV_UNREGISTER.
	467	*
	468	* If any packets are in flight down the CAIF Stack,
	469	* cfcnfg_del_phy_layer will return nonzero.
	470	* If no packets are in flight, the CAIF Stack associated
	471	* with the net-device un-registering is freed.
	472	*/
	473
	474	if (caifd_refcnt_read(caifd) != 0 \|\|
	475	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
	476
	477	pr_info("Wait for device inuse\n");
	478	/* Enrole device if CAIF Stack is still in use */
	479	list_add_rcu(&caifd->list, &caifdevs->list);
	480	mutex_unlock(&caifdevs->lock);
	481	break;
	482	}
	483
	484	synchronize_rcu();
	485	dev_put(caifd->netdev);
	486	free_percpu(caifd->pcpu_refcnt);
	487	kfree(caifd);
	488
	489	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	490	break;
	491	}
	492	return 0;
	493	}
	494
	495	static struct notifier_block caif_device_notifier = {
	496	.notifier_call = caif_device_notify,
	497	.priority = 0,
	498	};
	499
c72dfae2 SB	500	/* Per-namespace Caif devices handling */
	501	static int caif_init_net(struct net *net)
	502	{
	503	struct caif_net *caifn = net_generic(net, caif_net_id);
	504	INIT_LIST_HEAD(&caifn->caifdevs.list);
bd30ce4b	505	mutex_init(&caifn->caifdevs.lock);
bee925db	506
bee925db	507	caifn->cfg = cfcnfg_create();
f84ea779	508	if (!caifn->cfg)
bee925db	509	return -ENOMEM;
bee925db	510
c72dfae2 SB	511	return 0;
	512	}
	513
	514	static void caif_exit_net(struct net *net)
	515	{
bd30ce4b	516	struct caif_device_entry caifd, tmp;
	517	struct caif_device_entry_list *caifdevs =
	518	caif_device_list(net);
7c18d220	519	struct cfcnfg *cfg = get_cfcnfg(net);
7c18d220	520
c72dfae2	521	rtnl_lock();
bd30ce4b	522	mutex_lock(&caifdevs->lock);
	523
	524	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
	525	int i = 0;
	526	list_del_rcu(&caifd->list);
	527	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	528
	529	while (i < 10 &&
	530	(caifd_refcnt_read(caifd) != 0 \|\|
	531	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
	532
	533	pr_info("Wait for device inuse\n");
	534	msleep(250);
	535	i++;
	536	}
	537	synchronize_rcu();
	538	dev_put(caifd->netdev);
	539	free_percpu(caifd->pcpu_refcnt);
	540	kfree(caifd);
c72dfae2	541	}
bee925db	542	cfcnfg_remove(cfg);
bd30ce4b	543
bd30ce4b	544	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	545	rtnl_unlock();
	546	}
	547
	548	static struct pernet_operations caif_net_ops = {
	549	.init = caif_init_net,
	550	.exit = caif_exit_net,
	551	.id = &caif_net_id,
	552	.size = sizeof(struct caif_net),
	553	};
	554
	555	/* Initialize Caif devices list */
	556	static int __init caif_device_init(void)
	557	{
	558	int result;
bd30ce4b	559
8a8ee9af	560	result = register_pernet_subsys(&caif_net_ops);
c72dfae2	561
bee925db	562	if (result)
c72dfae2	563	return result;
bee925db	564
c72dfae2	565	register_netdevice_notifier(&caif_device_notifier);
bee925db	566	dev_add_pack(&caif_packet_type);
c72dfae2 SB	567
c72dfae2 SB	568	return result;
c72dfae2 SB	569	}
	570
	571	static void __exit caif_device_exit(void)
	572	{
c72dfae2	573	unregister_netdevice_notifier(&caif_device_notifier);
bee925db	574	dev_remove_pack(&caif_packet_type);
96f80d12	575	unregister_pernet_subsys(&caif_net_ops);
c72dfae2 SB	576	}
	577
	578	module_init(caif_device_init);
	579	module_exit(caif_device_exit);