[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / caif / caif_dev.c

/*
 * CAIF Interface registration.
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
 * License terms: GNU General Public License (GPL) version 2
 *
 * 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/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 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;
}

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);
	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->tx_queue_len == 0))
		goto noxoff;

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

	if (likely(!netif_queue_stopped(caifd->netdev))) {
		/* If we run with a TX queue, check if the queue is too long*/
		txq = netdev_get_tx_queue(skb->dev, 0);
		qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));

		if (likely(qlen == 0))
			goto noxoff;

		high = (caifd->netdev->tx_queue_len * q_high) / 100;
		if (likely(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);

	strncpy(caifd->layer.name, dev->name,
		sizeof(caifd->layer.name) - 1);
	caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
	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 *arg)
{
	struct net_device *dev = arg;
	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_pernet_subsys(&caif_net_ops);
	unregister_netdevice_notifier(&caif_device_notifier);
	dev_remove_pack(&caif_packet_type);
}

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