[linux-block.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_DESCRIPTION("ST-Ericsson CAIF modem protocol support");
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,
				lockdep_rtnl_is_held()) {
		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 = false;
	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 = true;
	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 free 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);
}

int 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;
	int res;

	caifdevs = caif_device_list(dev_net(dev));
	caifd = caif_device_alloc(dev);
	if (!caifd)
		return -ENOMEM;
	*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);

	strscpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name));
	caifd->layer.transmit = transmit;
	res = 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;
	return res;
}
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;
	int res;

	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;
			}
		}
		res = caif_enroll_dev(dev, caifdev, link_support, head_room,
				&layer, NULL);
		if (res)
			cfserl_release(link_support);
		caifdev->flowctrl = dev_flowctrl;
		break;

	case NETDEV_UP:
		rcu_read_lock();

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

		caifd->xoff = false;
		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 = false;
		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	29
cb420106	30	MODULE_DESCRIPTION("ST-Ericsson CAIF modem protocol support");
c72dfae2	31	MODULE_LICENSE("GPL");
c72dfae2 SB	32
	33	/* Used for local tracking of the CAIF net devices */
	34	struct caif_device_entry {
	35	struct cflayer layer;
	36	struct list_head list;
c72dfae2	37	struct net_device *netdev;
bd30ce4b	38	int __percpu *pcpu_refcnt;
0e4c7d85	39	spinlock_t flow_lock;
7d311304	40	struct sk_buff *xoff_skb;
7d311304	41	void (xoff_skb_dtor)(struct sk_buff skb);
0e4c7d85	42	bool xoff;
c72dfae2 SB	43	};
	44
	45	struct caif_device_entry_list {
	46	struct list_head list;
	47	/* Protects simulanous deletes in list */
bd30ce4b	48	struct mutex lock;
c72dfae2 SB	49	};
	50
	51	struct caif_net {
bee925db	52	struct cfcnfg *cfg;
c72dfae2 SB	53	struct caif_device_entry_list caifdevs;
	54	};
	55
c7d03a00	56	static unsigned int caif_net_id;
0e4c7d85	57	static int q_high = 50; /* Percent */
bee925db	58
	59	struct cfcnfg get_cfcnfg(struct net net)
	60	{
	61	struct caif_net *caifn;
bee925db	62	caifn = net_generic(net, caif_net_id);
bee925db	63	return caifn->cfg;
	64	}
	65	EXPORT_SYMBOL(get_cfcnfg);
c72dfae2 SB	66
	67	static struct caif_device_entry_list caif_device_list(struct net net)
	68	{
	69	struct caif_net *caifn;
c72dfae2	70	caifn = net_generic(net, caif_net_id);
c72dfae2 SB	71	return &caifn->caifdevs;
	72	}
	73
bd30ce4b	74	static void caifd_put(struct caif_device_entry *e)
bd30ce4b	75	{
933393f5	76	this_cpu_dec(*e->pcpu_refcnt);
bd30ce4b	77	}
	78
	79	static void caifd_hold(struct caif_device_entry *e)
	80	{
933393f5	81	this_cpu_inc(*e->pcpu_refcnt);
bd30ce4b	82	}
	83
	84	static int caifd_refcnt_read(struct caif_device_entry *e)
	85	{
	86	int i, refcnt = 0;
	87	for_each_possible_cpu(i)
	88	refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
	89	return refcnt;
	90	}
	91
c72dfae2 SB	92	/* Allocate new CAIF device. */
	93	static struct caif_device_entry caif_device_alloc(struct net_device dev)
	94	{
c72dfae2	95	struct caif_device_entry *caifd;
bd30ce4b	96
4fb66b82	97	caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
c72dfae2 SB	98	if (!caifd)
c72dfae2 SB	99	return NULL;
bd30ce4b	100	caifd->pcpu_refcnt = alloc_percpu(int);
4fb66b82 ED	101	if (!caifd->pcpu_refcnt) {
	102	kfree(caifd);
	103	return NULL;
	104	}
c72dfae2	105	caifd->netdev = dev;
bd30ce4b	106	dev_hold(dev);
c72dfae2 SB	107	return caifd;
	108	}
	109
	110	static struct caif_device_entry caif_get(struct net_device dev)
	111	{
	112	struct caif_device_entry_list *caifdevs =
	113	caif_device_list(dev_net(dev));
	114	struct caif_device_entry *caifd;
7c18d220	115
f9fc28a8 AG	116	list_for_each_entry_rcu(caifd, &caifdevs->list, list,
f9fc28a8 AG	117	lockdep_rtnl_is_held()) {
c72dfae2 SB	118	if (caifd->netdev == dev)
	119	return caifd;
	120	}
	121	return NULL;
	122	}
	123
d6e89c0b	124	static void caif_flow_cb(struct sk_buff *skb)
0e4c7d85	125	{
0e4c7d85	126	struct caif_device_entry *caifd;
7d311304	127	void (dtor)(struct sk_buff skb) = NULL;
0e4c7d85	128	bool send_xoff;
	129
	130	WARN_ON(skb->dev == NULL);
	131
	132	rcu_read_lock();
	133	caifd = caif_get(skb->dev);
c95567c8 KLX	134
c95567c8 KLX	135	WARN_ON(caifd == NULL);
64119e05 Y	136	if (!caifd) {
64119e05 Y	137	rcu_read_unlock();
c95567c8	138	return;
64119e05	139	}
c95567c8	140
0e4c7d85	141	caifd_hold(caifd);
	142	rcu_read_unlock();
	143
	144	spin_lock_bh(&caifd->flow_lock);
	145	send_xoff = caifd->xoff;
8518307d	146	caifd->xoff = false;
59f608d8	147	dtor = caifd->xoff_skb_dtor;
	148
	149	if (WARN_ON(caifd->xoff_skb != skb))
	150	skb = NULL;
	151
	152	caifd->xoff_skb = NULL;
	153	caifd->xoff_skb_dtor = NULL;
	154
0e4c7d85	155	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	156
59f608d8	157	if (dtor && skb)
7d311304	158	dtor(skb);
7d311304	159
0e4c7d85	160	if (send_xoff)
	161	caifd->layer.up->
	162	ctrlcmd(caifd->layer.up,
	163	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
	164	caifd->layer.id);
	165	caifd_put(caifd);
	166	}
	167
c72dfae2 SB	168	static int transmit(struct cflayer layer, struct cfpkt pkt)
c72dfae2 SB	169	{
0e4c7d85	170	int err, high = 0, qlen = 0;
c72dfae2 SB	171	struct caif_device_entry *caifd =
c72dfae2 SB	172	container_of(layer, struct caif_device_entry, layer);
4dd820c0	173	struct sk_buff *skb;
0e4c7d85	174	struct netdev_queue *txq;
	175
	176	rcu_read_lock_bh();
4dd820c0	177
c72dfae2 SB	178	skb = cfpkt_tonative(pkt);
c72dfae2 SB	179	skb->dev = caifd->netdev;
7c18d220	180	skb_reset_network_header(skb);
7c18d220	181	skb->protocol = htons(ETH_P_CAIF);
0e4c7d85	182
0e4c7d85	183	/* Check if we need to handle xoff */
4676a152	184	if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
0e4c7d85	185	goto noxoff;
	186
	187	if (unlikely(caifd->xoff))
	188	goto noxoff;
	189
	190	if (likely(!netif_queue_stopped(caifd->netdev))) {
b0a231a2 PA	191	struct Qdisc *sch;
b0a231a2 PA	192
0e4c7d85	193	/* If we run with a TX queue, check if the queue is too long*/
0e4c7d85	194	txq = netdev_get_tx_queue(skb->dev, 0);
b0a231a2 PA	195	sch = rcu_dereference_bh(txq->qdisc);
b0a231a2 PA	196	if (likely(qdisc_is_empty(sch)))
0e4c7d85	197	goto noxoff;
0e4c7d85	198
b0a231a2 PA	199	/* can check for explicit qdisc len value only !NOLOCK,
	200	* always set flow off otherwise
	201	*/
0e4c7d85	202	high = (caifd->netdev->tx_queue_len * q_high) / 100;
b0a231a2	203	if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
0e4c7d85	204	goto noxoff;
	205	}
	206
	207	/* Hold lock while accessing xoff */
	208	spin_lock_bh(&caifd->flow_lock);
	209	if (caifd->xoff) {
	210	spin_unlock_bh(&caifd->flow_lock);
	211	goto noxoff;
	212	}
	213
	214	/*
	215	* Handle flow off, we do this by temporary hi-jacking this
	216	* skb's destructor function, and replace it with our own
	217	* flow-on callback. The callback will set flow-on and call
	218	* the original destructor.
	219	*/
	220
	221	pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
	222	netif_queue_stopped(caifd->netdev),
	223	qlen, high);
8518307d	224	caifd->xoff = true;
7d311304	225	caifd->xoff_skb = skb;
	226	caifd->xoff_skb_dtor = skb->destructor;
	227	skb->destructor = caif_flow_cb;
0e4c7d85	228	spin_unlock_bh(&caifd->flow_lock);
0e4c7d85	229
	230	caifd->layer.up->ctrlcmd(caifd->layer.up,
	231	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	232	caifd->layer.id);
	233	noxoff:
	234	rcu_read_unlock_bh();
4dd820c0	235
c85c2951	236	err = dev_queue_xmit(skb);
	237	if (err > 0)
	238	err = -EIO;
c72dfae2	239
c85c2951	240	return err;
c72dfae2 SB	241	}
c72dfae2 SB	242
c72dfae2	243	/*
bd30ce4b	244	* Stuff received packets into the CAIF stack.
c72dfae2 SB	245	* On error, returns non-zero and releases the skb.
	246	*/
	247	static int receive(struct sk_buff skb, struct net_device dev,
	248	struct packet_type pkttype, struct net_device orig_dev)
	249	{
c72dfae2 SB	250	struct cfpkt *pkt;
c72dfae2 SB	251	struct caif_device_entry *caifd;
69c867c9	252	int err;
bd30ce4b	253
c72dfae2	254	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
bd30ce4b	255
bd30ce4b	256	rcu_read_lock();
c72dfae2	257	caifd = caif_get(dev);
c72dfae2	258
bd30ce4b	259	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->receive \|\|
	260	!netif_oper_up(caifd->netdev)) {
	261	rcu_read_unlock();
	262	kfree_skb(skb);
c72dfae2	263	return NET_RX_DROP;
bd30ce4b	264	}
	265
	266	/* Hold reference to netdevice while using CAIF stack */
	267	caifd_hold(caifd);
	268	rcu_read_unlock();
c72dfae2	269
69c867c9	270	err = caifd->layer.up->receive(caifd->layer.up, pkt);
69c867c9	271
0812beb7	272	/* For -EILSEQ the packet is not freed so free it now */
69c867c9	273	if (err == -EILSEQ)
69c867c9	274	cfpkt_destroy(pkt);
bd30ce4b	275
	276	/* Release reference to stack upwards */
	277	caifd_put(caifd);
7c18d220	278
	279	if (err != 0)
	280	err = NET_RX_DROP;
	281	return err;
c72dfae2 SB	282	}
	283
	284	static struct packet_type caif_packet_type __read_mostly = {
	285	.type = cpu_to_be16(ETH_P_CAIF),
	286	.func = receive,
	287	};
	288
	289	static void dev_flowctrl(struct net_device *dev, int on)
	290	{
bd30ce4b	291	struct caif_device_entry *caifd;
	292
	293	rcu_read_lock();
	294
	295	caifd = caif_get(dev);
	296	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	297	rcu_read_unlock();
c72dfae2	298	return;
bd30ce4b	299	}
	300
	301	caifd_hold(caifd);
	302	rcu_read_unlock();
c72dfae2 SB	303
	304	caifd->layer.up->ctrlcmd(caifd->layer.up,
	305	on ?
	306	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
	307	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
	308	caifd->layer.id);
bd30ce4b	309	caifd_put(caifd);
c72dfae2 SB	310	}
c72dfae2 SB	311
a2805dca	312	int caif_enroll_dev(struct net_device dev, struct caif_dev_common caifdev,
3bffc475 SMP	313	struct cflayer *link_support, int head_room,
	314	struct cflayer **layer,
	315	int (*rcv_func)(struct sk_buff , struct net_device *,
	316	struct packet_type *,
	317	struct net_device *))
7c18d220	318	{
	319	struct caif_device_entry *caifd;
	320	enum cfcnfg_phy_preference pref;
	321	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
	322	struct caif_device_entry_list *caifdevs;
a2805dca	323	int res;
7c18d220	324
7c18d220	325	caifdevs = caif_device_list(dev_net(dev));
7c18d220	326	caifd = caif_device_alloc(dev);
7c18d220	327	if (!caifd)
a2805dca	328	return -ENOMEM;
7c18d220	329	*layer = &caifd->layer;
0e4c7d85	330	spin_lock_init(&caifd->flow_lock);
7c18d220	331
	332	switch (caifdev->link_select) {
	333	case CAIF_LINK_HIGH_BANDW:
	334	pref = CFPHYPREF_HIGH_BW;
	335	break;
	336	case CAIF_LINK_LOW_LATENCY:
	337	pref = CFPHYPREF_LOW_LAT;
	338	break;
	339	default:
	340	pref = CFPHYPREF_HIGH_BW;
	341	break;
	342	}
	343	mutex_lock(&caifdevs->lock);
	344	list_add_rcu(&caifd->list, &caifdevs->list);
	345
df207b00	346	strscpy(caifd->layer.name, dev->name,
3dc2fa47	347	sizeof(caifd->layer.name));
7c18d220	348	caifd->layer.transmit = transmit;
a2805dca	349	res = cfcnfg_add_phy_layer(cfg,
7c18d220	350	dev,
	351	&caifd->layer,
	352	pref,
	353	link_support,
	354	caifdev->use_fcs,
	355	head_room);
	356	mutex_unlock(&caifdevs->lock);
	357	if (rcv_func)
	358	*rcv_func = receive;
a2805dca	359	return res;
7c18d220	360	}
7ad65bf6	361	EXPORT_SYMBOL(caif_enroll_dev);
7c18d220	362
c72dfae2 SB	363	/* notify Caif of device events */
c72dfae2 SB	364	static int caif_device_notify(struct notifier_block *me, unsigned long what,
351638e7	365	void *ptr)
c72dfae2	366	{
351638e7	367	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
c72dfae2 SB	368	struct caif_device_entry *caifd = NULL;
c72dfae2 SB	369	struct caif_dev_common *caifdev;
bee925db	370	struct cfcnfg *cfg;
7c18d220	371	struct cflayer layer, link_support;
7c18d220	372	int head_room = 0;
08613e46	373	struct caif_device_entry_list *caifdevs;
b53558a9	374	int res;
c72dfae2	375
bee925db	376	cfg = get_cfcnfg(dev_net(dev));
7c18d220	377	caifdevs = caif_device_list(dev_net(dev));
bee925db	378
7c18d220	379	caifd = caif_get(dev);
	380	if (caifd == NULL && dev->type != ARPHRD_CAIF)
	381	return 0;
08613e46	382
c72dfae2 SB	383	switch (what) {
c72dfae2 SB	384	case NETDEV_REGISTER:
7c18d220	385	if (caifd != NULL)
7c18d220	386	break;
bd30ce4b	387
c72dfae2	388	caifdev = netdev_priv(dev);
c72dfae2	389
7c18d220	390	link_support = NULL;
	391	if (caifdev->use_frag) {
	392	head_room = 1;
	393	link_support = cfserl_create(dev->ifindex,
e977b4cf	394	caifdev->use_stx);
7c18d220	395	if (!link_support) {
	396	pr_warn("Out of memory\n");
	397	break;
	398	}
c72dfae2	399	}
b53558a9	400	res = caif_enroll_dev(dev, caifdev, link_support, head_room,
7c18d220	401	&layer, NULL);
b53558a9 PS	402	if (res)
b53558a9 PS	403	cfserl_release(link_support);
7c18d220	404	caifdev->flowctrl = dev_flowctrl;
c72dfae2 SB	405	break;
c72dfae2 SB	406
bd30ce4b	407	case NETDEV_UP:
	408	rcu_read_lock();
	409
c72dfae2	410	caifd = caif_get(dev);
bd30ce4b	411	if (caifd == NULL) {
bd30ce4b	412	rcu_read_unlock();
c72dfae2	413	break;
bd30ce4b	414	}
c72dfae2	415
8518307d	416	caifd->xoff = false;
bd30ce4b	417	cfcnfg_set_phy_state(cfg, &caifd->layer, true);
bd30ce4b	418	rcu_read_unlock();
c72dfae2	419
c72dfae2 SB	420	break;
	421
	422	case NETDEV_DOWN:
bd30ce4b	423	rcu_read_lock();
bd30ce4b	424
c72dfae2	425	caifd = caif_get(dev);
bd30ce4b	426	if (!caifd \|\| !caifd->layer.up \|\| !caifd->layer.up->ctrlcmd) {
	427	rcu_read_unlock();
	428	return -EINVAL;
	429	}
	430
	431	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	432	caifd_hold(caifd);
	433	rcu_read_unlock();
	434
	435	caifd->layer.up->ctrlcmd(caifd->layer.up,
	436	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
	437	caifd->layer.id);
7d311304	438
	439	spin_lock_bh(&caifd->flow_lock);
	440
	441	/*
	442	* Replace our xoff-destructor with original destructor.
	443	* We trust that skb->destructor always is called before
	444	* the skb reference is invalid. The hijacked SKB destructor
	445	* takes the flow_lock so manipulating the skb->destructor here
	446	* should be safe.
	447	*/
	448	if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
	449	caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
	450
8518307d	451	caifd->xoff = false;
7d311304	452	caifd->xoff_skb_dtor = NULL;
	453	caifd->xoff_skb = NULL;
	454
	455	spin_unlock_bh(&caifd->flow_lock);
bd30ce4b	456	caifd_put(caifd);
c72dfae2 SB	457	break;
	458
	459	case NETDEV_UNREGISTER:
bd30ce4b	460	mutex_lock(&caifdevs->lock);
bd30ce4b	461
c72dfae2	462	caifd = caif_get(dev);
bd30ce4b	463	if (caifd == NULL) {
bd30ce4b	464	mutex_unlock(&caifdevs->lock);
f2527ec4	465	break;
bd30ce4b	466	}
	467	list_del_rcu(&caifd->list);
	468
	469	/*
	470	* NETDEV_UNREGISTER is called repeatedly until all reference
	471	* counts for the net-device are released. If references to
	472	* caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
	473	* the next call to NETDEV_UNREGISTER.
	474	*
	475	* If any packets are in flight down the CAIF Stack,
	476	* cfcnfg_del_phy_layer will return nonzero.
	477	* If no packets are in flight, the CAIF Stack associated
	478	* with the net-device un-registering is freed.
	479	*/
	480
	481	if (caifd_refcnt_read(caifd) != 0 \|\|
	482	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
	483
	484	pr_info("Wait for device inuse\n");
	485	/* Enrole device if CAIF Stack is still in use */
	486	list_add_rcu(&caifd->list, &caifdevs->list);
	487	mutex_unlock(&caifdevs->lock);
	488	break;
	489	}
	490
	491	synchronize_rcu();
	492	dev_put(caifd->netdev);
	493	free_percpu(caifd->pcpu_refcnt);
	494	kfree(caifd);
	495
	496	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	497	break;
	498	}
	499	return 0;
	500	}
	501
	502	static struct notifier_block caif_device_notifier = {
	503	.notifier_call = caif_device_notify,
	504	.priority = 0,
	505	};
	506
c72dfae2 SB	507	/* Per-namespace Caif devices handling */
	508	static int caif_init_net(struct net *net)
	509	{
	510	struct caif_net *caifn = net_generic(net, caif_net_id);
	511	INIT_LIST_HEAD(&caifn->caifdevs.list);
bd30ce4b	512	mutex_init(&caifn->caifdevs.lock);
bee925db	513
bee925db	514	caifn->cfg = cfcnfg_create();
f84ea779	515	if (!caifn->cfg)
bee925db	516	return -ENOMEM;
bee925db	517
c72dfae2 SB	518	return 0;
	519	}
	520
	521	static void caif_exit_net(struct net *net)
	522	{
bd30ce4b	523	struct caif_device_entry caifd, tmp;
	524	struct caif_device_entry_list *caifdevs =
	525	caif_device_list(net);
7c18d220	526	struct cfcnfg *cfg = get_cfcnfg(net);
7c18d220	527
c72dfae2	528	rtnl_lock();
bd30ce4b	529	mutex_lock(&caifdevs->lock);
	530
	531	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
	532	int i = 0;
	533	list_del_rcu(&caifd->list);
	534	cfcnfg_set_phy_state(cfg, &caifd->layer, false);
	535
	536	while (i < 10 &&
	537	(caifd_refcnt_read(caifd) != 0 \|\|
	538	cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
	539
	540	pr_info("Wait for device inuse\n");
	541	msleep(250);
	542	i++;
	543	}
	544	synchronize_rcu();
	545	dev_put(caifd->netdev);
	546	free_percpu(caifd->pcpu_refcnt);
	547	kfree(caifd);
c72dfae2	548	}
bee925db	549	cfcnfg_remove(cfg);
bd30ce4b	550
bd30ce4b	551	mutex_unlock(&caifdevs->lock);
c72dfae2 SB	552	rtnl_unlock();
	553	}
	554
	555	static struct pernet_operations caif_net_ops = {
	556	.init = caif_init_net,
	557	.exit = caif_exit_net,
	558	.id = &caif_net_id,
	559	.size = sizeof(struct caif_net),
	560	};
	561
	562	/* Initialize Caif devices list */
	563	static int __init caif_device_init(void)
	564	{
	565	int result;
bd30ce4b	566
8a8ee9af	567	result = register_pernet_subsys(&caif_net_ops);
c72dfae2	568
bee925db	569	if (result)
c72dfae2	570	return result;
bee925db	571
c72dfae2	572	register_netdevice_notifier(&caif_device_notifier);
bee925db	573	dev_add_pack(&caif_packet_type);
c72dfae2 SB	574
c72dfae2 SB	575	return result;
c72dfae2 SB	576	}
	577
	578	static void __exit caif_device_exit(void)
	579	{
c72dfae2	580	unregister_netdevice_notifier(&caif_device_notifier);
bee925db	581	dev_remove_pack(&caif_packet_type);
96f80d12	582	unregister_pernet_subsys(&caif_net_ops);
c72dfae2 SB	583	}
	584
	585	module_init(caif_device_init);
	586	module_exit(caif_device_exit);