[deliverable/linux.git] / drivers / net / caif / caif_serial.c

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

#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/if_arp.h>
#include <net/caif/caif_device.h>
#include <net/caif/cfcnfg.h>
#include <linux/err.h>
#include <linux/debugfs.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sjur Brendeland<sjur.brandeland@stericsson.com>");
MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_CAIF);

#define SEND_QUEUE_LOW 10
#define SEND_QUEUE_HIGH 100
#define CAIF_SENDING	        1 /* Bit 1 = 0x02*/
#define CAIF_FLOW_OFF_SENT	4 /* Bit 4 = 0x10 */
#define MAX_WRITE_CHUNK	     4096
#define ON 1
#define OFF 0
#define CAIF_MAX_MTU 4096

/*This list is protected by the rtnl lock. */
static LIST_HEAD(ser_list);

static bool ser_loop;
module_param(ser_loop, bool, S_IRUGO);
MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");

static bool ser_use_stx = true;
module_param(ser_use_stx, bool, S_IRUGO);
MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");

static bool ser_use_fcs = true;

module_param(ser_use_fcs, bool, S_IRUGO);
MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");

static int ser_write_chunk = MAX_WRITE_CHUNK;
module_param(ser_write_chunk, int, S_IRUGO);

MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");

static struct dentry *debugfsdir;

static int caif_net_open(struct net_device *dev);
static int caif_net_close(struct net_device *dev);

struct ser_device {
	struct caif_dev_common common;
	struct list_head node;
	struct net_device *dev;
	struct sk_buff_head head;
	struct tty_struct *tty;
	bool tx_started;
	unsigned long state;
	char *tty_name;
#ifdef CONFIG_DEBUG_FS
	struct dentry *debugfs_tty_dir;
	struct debugfs_blob_wrapper tx_blob;
	struct debugfs_blob_wrapper rx_blob;
	u8 rx_data[128];
	u8 tx_data[128];
	u8 tty_status;

#endif
};

static void caifdev_setup(struct net_device *dev);
static void ldisc_tx_wakeup(struct tty_struct *tty);
#ifdef CONFIG_DEBUG_FS
static inline void update_tty_status(struct ser_device *ser)
{
	ser->tty_status =
		ser->tty->stopped << 5 |
		ser->tty->hw_stopped << 4 |
		ser->tty->flow_stopped << 3 |
		ser->tty->packet << 2 |
		ser->tty->low_latency << 1 |
		ser->tty->warned;
}
static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
{
	ser->debugfs_tty_dir =
			debugfs_create_dir(tty->name, debugfsdir);
	if (!IS_ERR(ser->debugfs_tty_dir)) {
		debugfs_create_blob("last_tx_msg", S_IRUSR,
				ser->debugfs_tty_dir,
				&ser->tx_blob);

		debugfs_create_blob("last_rx_msg", S_IRUSR,
				ser->debugfs_tty_dir,
				&ser->rx_blob);

		debugfs_create_x32("ser_state", S_IRUSR,
				ser->debugfs_tty_dir,
				(u32 *)&ser->state);

		debugfs_create_x8("tty_status", S_IRUSR,
				ser->debugfs_tty_dir,
				&ser->tty_status);

	}
	ser->tx_blob.data = ser->tx_data;
	ser->tx_blob.size = 0;
	ser->rx_blob.data = ser->rx_data;
	ser->rx_blob.size = 0;
}

static inline void debugfs_deinit(struct ser_device *ser)
{
	debugfs_remove_recursive(ser->debugfs_tty_dir);
}

static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
{
	if (size > sizeof(ser->rx_data))
		size = sizeof(ser->rx_data);
	memcpy(ser->rx_data, data, size);
	ser->rx_blob.data = ser->rx_data;
	ser->rx_blob.size = size;
}

static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
{
	if (size > sizeof(ser->tx_data))
		size = sizeof(ser->tx_data);
	memcpy(ser->tx_data, data, size);
	ser->tx_blob.data = ser->tx_data;
	ser->tx_blob.size = size;
}
#else
static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
{
}

static inline void debugfs_deinit(struct ser_device *ser)
{
}

static inline void update_tty_status(struct ser_device *ser)
{
}

static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
{
}

static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
{
}

#endif

static void ldisc_receive(struct tty_struct *tty, const u8 *data,
			char *flags, int count)
{
	struct sk_buff *skb = NULL;
	struct ser_device *ser;
	int ret;
	u8 *p;

	ser = tty->disc_data;

	/*
	 * NOTE: flags may contain information about break or overrun.
	 * This is not yet handled.
	 */


	/*
	 * Workaround for garbage at start of transmission,
	 * only enable if STX handling is not enabled.
	 */
	if (!ser->common.use_stx && !ser->tx_started) {
		dev_info(&ser->dev->dev,
			"Bytes received before initial transmission -"
			"bytes discarded.\n");
		return;
	}

	BUG_ON(ser->dev == NULL);

	/* Get a suitable caif packet and copy in data. */
	skb = netdev_alloc_skb(ser->dev, count+1);
	if (skb == NULL)
		return;
	p = skb_put(skb, count);
	memcpy(p, data, count);

	skb->protocol = htons(ETH_P_CAIF);
	skb_reset_mac_header(skb);
	skb->dev = ser->dev;
	debugfs_rx(ser, data, count);
	/* Push received packet up the stack. */
	ret = netif_rx_ni(skb);
	if (!ret) {
		ser->dev->stats.rx_packets++;
		ser->dev->stats.rx_bytes += count;
	} else
		++ser->dev->stats.rx_dropped;
	update_tty_status(ser);
}

static int handle_tx(struct ser_device *ser)
{
	struct tty_struct *tty;
	struct sk_buff *skb;
	int tty_wr, len, room;

	tty = ser->tty;
	ser->tx_started = true;

	/* Enter critical section */
	if (test_and_set_bit(CAIF_SENDING, &ser->state))
		return 0;

	/* skb_peek is safe because handle_tx is called after skb_queue_tail */
	while ((skb = skb_peek(&ser->head)) != NULL) {

		/* Make sure you don't write too much */
		len = skb->len;
		room = tty_write_room(tty);
		if (!room)
			break;
		if (room > ser_write_chunk)
			room = ser_write_chunk;
		if (len > room)
			len = room;

		/* Write to tty or loopback */
		if (!ser_loop) {
			tty_wr = tty->ops->write(tty, skb->data, len);
			update_tty_status(ser);
		} else {
			tty_wr = len;
			ldisc_receive(tty, skb->data, NULL, len);
		}
		ser->dev->stats.tx_packets++;
		ser->dev->stats.tx_bytes += tty_wr;

		/* Error on TTY ?! */
		if (tty_wr < 0)
			goto error;
		/* Reduce buffer written, and discard if empty */
		skb_pull(skb, tty_wr);
		if (skb->len == 0) {
			struct sk_buff *tmp = skb_dequeue(&ser->head);
			WARN_ON(tmp != skb);
			if (in_interrupt())
				dev_kfree_skb_irq(skb);
			else
				kfree_skb(skb);
		}
	}
	/* Send flow off if queue is empty */
	if (ser->head.qlen <= SEND_QUEUE_LOW &&
		test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
		ser->common.flowctrl != NULL)
				ser->common.flowctrl(ser->dev, ON);
	clear_bit(CAIF_SENDING, &ser->state);
	return 0;
error:
	clear_bit(CAIF_SENDING, &ser->state);
	return tty_wr;
}

static int caif_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct ser_device *ser;

	BUG_ON(dev == NULL);
	ser = netdev_priv(dev);

	/* Send flow off once, on high water mark */
	if (ser->head.qlen > SEND_QUEUE_HIGH &&
		!test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
		ser->common.flowctrl != NULL)

		ser->common.flowctrl(ser->dev, OFF);

	skb_queue_tail(&ser->head, skb);
	return handle_tx(ser);
}


static void ldisc_tx_wakeup(struct tty_struct *tty)
{
	struct ser_device *ser;

	ser = tty->disc_data;
	BUG_ON(ser == NULL);
	WARN_ON(ser->tty != tty);
	handle_tx(ser);
}


static int ldisc_open(struct tty_struct *tty)
{
	struct ser_device *ser;
	struct net_device *dev;
	char name[64];
	int result;

	/* No write no play */
	if (tty->ops->write == NULL)
		return -EOPNOTSUPP;
	if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
		return -EPERM;

	sprintf(name, "cf%s", tty->name);
	dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
	ser = netdev_priv(dev);
	ser->tty = tty_kref_get(tty);
	ser->dev = dev;
	debugfs_init(ser, tty);
	tty->receive_room = N_TTY_BUF_SIZE;
	tty->disc_data = ser;
	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
	rtnl_lock();
	result = register_netdevice(dev);
	if (result) {
		rtnl_unlock();
		free_netdev(dev);
		return -ENODEV;
	}

	list_add(&ser->node, &ser_list);
	rtnl_unlock();
	netif_stop_queue(dev);
	update_tty_status(ser);
	return 0;
}

static void ldisc_close(struct tty_struct *tty)
{
	struct ser_device *ser = tty->disc_data;
	/* Remove may be called inside or outside of rtnl_lock */
	int islocked = rtnl_is_locked();

	if (!islocked)
		rtnl_lock();
	/* device is freed automagically by net-sysfs */
	dev_close(ser->dev);
	unregister_netdevice(ser->dev);
	list_del(&ser->node);
	debugfs_deinit(ser);
	tty_kref_put(ser->tty);
	if (!islocked)
		rtnl_unlock();
}

/* The line discipline structure. */
static struct tty_ldisc_ops caif_ldisc = {
	.owner =	THIS_MODULE,
	.magic =	TTY_LDISC_MAGIC,
	.name =		"n_caif",
	.open =		ldisc_open,
	.close =	ldisc_close,
	.receive_buf =	ldisc_receive,
	.write_wakeup =	ldisc_tx_wakeup
};

static int register_ldisc(void)
{
	int result;

	result = tty_register_ldisc(N_CAIF, &caif_ldisc);
	if (result < 0) {
		pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
			result);
		return result;
	}
	return result;
}
static const struct net_device_ops netdev_ops = {
	.ndo_open = caif_net_open,
	.ndo_stop = caif_net_close,
	.ndo_start_xmit = caif_xmit
};

static void caifdev_setup(struct net_device *dev)
{
	struct ser_device *serdev = netdev_priv(dev);

	dev->features = 0;
	dev->netdev_ops = &netdev_ops;
	dev->type = ARPHRD_CAIF;
	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
	dev->mtu = CAIF_MAX_MTU;
	dev->tx_queue_len = 0;
	dev->destructor = free_netdev;
	skb_queue_head_init(&serdev->head);
	serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
	serdev->common.use_frag = true;
	serdev->common.use_stx = ser_use_stx;
	serdev->common.use_fcs = ser_use_fcs;
	serdev->dev = dev;
}


static int caif_net_open(struct net_device *dev)
{
	netif_wake_queue(dev);
	return 0;
}

static int caif_net_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

static int __init caif_ser_init(void)
{
	int ret;

	ret = register_ldisc();
	debugfsdir = debugfs_create_dir("caif_serial", NULL);
	return ret;
}

static void __exit caif_ser_exit(void)
{
	struct ser_device *ser = NULL;
	struct list_head *node;
	struct list_head *_tmp;

	list_for_each_safe(node, _tmp, &ser_list) {
		ser = list_entry(node, struct ser_device, node);
		dev_close(ser->dev);
		unregister_netdevice(ser->dev);
		list_del(node);
	}
	tty_unregister_ldisc(N_CAIF);
	debugfs_remove_recursive(debugfsdir);
}

module_init(caif_ser_init);
module_exit(caif_ser_exit);
Commit	Line	Data
9b27105b SB	1	/*
	2	* Copyright (C) ST-Ericsson AB 2010
	3	* Author: Sjur Brendeland / sjur.brandeland@stericsson.com
	4	* License terms: GNU General Public License (GPL) version 2
	5	*/
	6
a6b7a407	7	#include <linux/hardirq.h>
9b27105b	8	#include <linux/init.h>
9b27105b SB	9	#include <linux/module.h>
	10	#include <linux/device.h>
	11	#include <linux/types.h>
	12	#include <linux/skbuff.h>
	13	#include <linux/netdevice.h>
	14	#include <linux/rtnetlink.h>
	15	#include <linux/tty.h>
	16	#include <linux/file.h>
	17	#include <linux/if_arp.h>
	18	#include <net/caif/caif_device.h>
	19	#include <net/caif/cfcnfg.h>
	20	#include <linux/err.h>
	21	#include <linux/debugfs.h>
	22
	23	MODULE_LICENSE("GPL");
	24	MODULE_AUTHOR("Sjur Brendeland<sjur.brandeland@stericsson.com>");
	25	MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
	26	MODULE_LICENSE("GPL");
	27	MODULE_ALIAS_LDISC(N_CAIF);
	28
	29	#define SEND_QUEUE_LOW 10
	30	#define SEND_QUEUE_HIGH 100
	31	#define CAIF_SENDING 1 /* Bit 1 = 0x02*/
	32	#define CAIF_FLOW_OFF_SENT 4 /* Bit 4 = 0x10 */
	33	#define MAX_WRITE_CHUNK 4096
	34	#define ON 1
	35	#define OFF 0
	36	#define CAIF_MAX_MTU 4096
	37
	38	/This list is protected by the rtnl lock. /
	39	static LIST_HEAD(ser_list);
	40
eb939922	41	static bool ser_loop;
9b27105b SB	42	module_param(ser_loop, bool, S_IRUGO);
	43	MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
	44
eb939922	45	static bool ser_use_stx = true;
9b27105b SB	46	module_param(ser_use_stx, bool, S_IRUGO);
	47	MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
	48
eb939922	49	static bool ser_use_fcs = true;
9b27105b SB	50
	51	module_param(ser_use_fcs, bool, S_IRUGO);
	52	MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
	53
	54	static int ser_write_chunk = MAX_WRITE_CHUNK;
	55	module_param(ser_write_chunk, int, S_IRUGO);
	56
	57	MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");
	58
	59	static struct dentry *debugfsdir;
	60
	61	static int caif_net_open(struct net_device *dev);
	62	static int caif_net_close(struct net_device *dev);
	63
	64	struct ser_device {
	65	struct caif_dev_common common;
	66	struct list_head node;
	67	struct net_device *dev;
	68	struct sk_buff_head head;
	69	struct tty_struct *tty;
	70	bool tx_started;
	71	unsigned long state;
	72	char *tty_name;
	73	#ifdef CONFIG_DEBUG_FS
	74	struct dentry *debugfs_tty_dir;
	75	struct debugfs_blob_wrapper tx_blob;
	76	struct debugfs_blob_wrapper rx_blob;
	77	u8 rx_data[128];
	78	u8 tx_data[128];
	79	u8 tty_status;
	80
	81	#endif
	82	};
	83
	84	static void caifdev_setup(struct net_device *dev);
	85	static void ldisc_tx_wakeup(struct tty_struct *tty);
	86	#ifdef CONFIG_DEBUG_FS
	87	static inline void update_tty_status(struct ser_device *ser)
	88	{
	89	ser->tty_status =
	90	ser->tty->stopped << 5 \|
	91	ser->tty->hw_stopped << 4 \|
	92	ser->tty->flow_stopped << 3 \|
	93	ser->tty->packet << 2 \|
	94	ser->tty->low_latency << 1 \|
	95	ser->tty->warned;
	96	}
	97	static inline void debugfs_init(struct ser_device ser, struct tty_struct tty)
	98	{
	99	ser->debugfs_tty_dir =
	100	debugfs_create_dir(tty->name, debugfsdir);
	101	if (!IS_ERR(ser->debugfs_tty_dir)) {
	102	debugfs_create_blob("last_tx_msg", S_IRUSR,
	103	ser->debugfs_tty_dir,
	104	&ser->tx_blob);
	105
	106	debugfs_create_blob("last_rx_msg", S_IRUSR,
	107	ser->debugfs_tty_dir,
	108	&ser->rx_blob);
	109
	110	debugfs_create_x32("ser_state", S_IRUSR,
	111	ser->debugfs_tty_dir,
	112	(u32 *)&ser->state);
	113
114	debugfs_create_x8("tty_status", S_IRUSR,
115	ser->debugfs_tty_dir,
116	&ser->tty_status);
117
118	}
119	ser->tx_blob.data = ser->tx_data;
120	ser->tx_blob.size = 0;
121	ser->rx_blob.data = ser->rx_data;
122	ser->rx_blob.size = 0;
123	}
124
125	static inline void debugfs_deinit(struct ser_device *ser)
126	{
127	debugfs_remove_recursive(ser->debugfs_tty_dir);
128	}
129
130	static inline void debugfs_rx(struct ser_device ser, const u8 data, int size)
131	{
132	if (size > sizeof(ser->rx_data))
133	size = sizeof(ser->rx_data);
134	memcpy(ser->rx_data, data, size);
135	ser->rx_blob.data = ser->rx_data;
136	ser->rx_blob.size = size;
137	}
138
139	static inline void debugfs_tx(struct ser_device ser, const u8 data, int size)
140	{
141	if (size > sizeof(ser->tx_data))
142	size = sizeof(ser->tx_data);
143	memcpy(ser->tx_data, data, size);
144	ser->tx_blob.data = ser->tx_data;
145	ser->tx_blob.size = size;
146	}
147	#else
148	static inline void debugfs_init(struct ser_device ser, struct tty_struct tty)
149	{
150	}
151
152	static inline void debugfs_deinit(struct ser_device *ser)
153	{
154	}
155
156	static inline void update_tty_status(struct ser_device *ser)
157	{
158	}
159
160	static inline void debugfs_rx(struct ser_device ser, const u8 data, int size)
161	{
162	}
163
164	static inline void debugfs_tx(struct ser_device ser, const u8 data, int size)
165	{
166	}
167
168	#endif
169
55db4c64 LT	170	static void ldisc_receive(struct tty_struct tty, const u8 data,
55db4c64 LT	171	char *flags, int count)
9b27105b SB	172	{
	173	struct sk_buff *skb = NULL;
	174	struct ser_device *ser;
	175	int ret;
	176	u8 *p;
c1f8fc57	177
9b27105b SB	178	ser = tty->disc_data;
	179
	180	/*
	181	* NOTE: flags may contain information about break or overrun.
	182	* This is not yet handled.
	183	*/
	184
	185
	186	/*
	187	* Workaround for garbage at start of transmission,
	188	* only enable if STX handling is not enabled.
	189	*/
	190	if (!ser->common.use_stx && !ser->tx_started) {
	191	dev_info(&ser->dev->dev,
	192	"Bytes received before initial transmission -"
	193	"bytes discarded.\n");
	194	return;
	195	}
	196
	197	BUG_ON(ser->dev == NULL);
	198
	199	/* Get a suitable caif packet and copy in data. */
	200	skb = netdev_alloc_skb(ser->dev, count+1);
d3f744e0 SB	201	if (skb == NULL)
d3f744e0 SB	202	return;
9b27105b SB	203	p = skb_put(skb, count);
	204	memcpy(p, data, count);
	205
	206	skb->protocol = htons(ETH_P_CAIF);
	207	skb_reset_mac_header(skb);
	208	skb->dev = ser->dev;
	209	debugfs_rx(ser, data, count);
	210	/* Push received packet up the stack. */
	211	ret = netif_rx_ni(skb);
	212	if (!ret) {
	213	ser->dev->stats.rx_packets++;
	214	ser->dev->stats.rx_bytes += count;
	215	} else
	216	++ser->dev->stats.rx_dropped;
	217	update_tty_status(ser);
	218	}
	219
	220	static int handle_tx(struct ser_device *ser)
	221	{
	222	struct tty_struct *tty;
	223	struct sk_buff *skb;
	224	int tty_wr, len, room;
c1f8fc57	225
9b27105b SB	226	tty = ser->tty;
	227	ser->tx_started = true;
	228
	229	/* Enter critical section */
	230	if (test_and_set_bit(CAIF_SENDING, &ser->state))
	231	return 0;
	232
	233	/* skb_peek is safe because handle_tx is called after skb_queue_tail */
	234	while ((skb = skb_peek(&ser->head)) != NULL) {
	235
	236	/* Make sure you don't write too much */
	237	len = skb->len;
	238	room = tty_write_room(tty);
	239	if (!room)
	240	break;
	241	if (room > ser_write_chunk)
	242	room = ser_write_chunk;
	243	if (len > room)
	244	len = room;
	245
	246	/* Write to tty or loopback */
	247	if (!ser_loop) {
	248	tty_wr = tty->ops->write(tty, skb->data, len);
	249	update_tty_status(ser);
	250	} else {
	251	tty_wr = len;
	252	ldisc_receive(tty, skb->data, NULL, len);
	253	}
	254	ser->dev->stats.tx_packets++;
	255	ser->dev->stats.tx_bytes += tty_wr;
	256
	257	/* Error on TTY ?! */
	258	if (tty_wr < 0)
	259	goto error;
	260	/* Reduce buffer written, and discard if empty */
	261	skb_pull(skb, tty_wr);
	262	if (skb->len == 0) {
	263	struct sk_buff *tmp = skb_dequeue(&ser->head);
f84ea779	264	WARN_ON(tmp != skb);
9b27105b SB	265	if (in_interrupt())
	266	dev_kfree_skb_irq(skb);
	267	else
	268	kfree_skb(skb);
	269	}
	270	}
	271	/* Send flow off if queue is empty */
	272	if (ser->head.qlen <= SEND_QUEUE_LOW &&
	273	test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
	274	ser->common.flowctrl != NULL)
	275	ser->common.flowctrl(ser->dev, ON);
	276	clear_bit(CAIF_SENDING, &ser->state);
	277	return 0;
	278	error:
	279	clear_bit(CAIF_SENDING, &ser->state);
	280	return tty_wr;
	281	}
	282
	283	static int caif_xmit(struct sk_buff skb, struct net_device dev)
	284	{
	285	struct ser_device *ser;
c1f8fc57	286
9b27105b SB	287	BUG_ON(dev == NULL);
	288	ser = netdev_priv(dev);
	289
	290	/* Send flow off once, on high water mark */
	291	if (ser->head.qlen > SEND_QUEUE_HIGH &&
	292	!test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
	293	ser->common.flowctrl != NULL)
	294
	295	ser->common.flowctrl(ser->dev, OFF);
	296
	297	skb_queue_tail(&ser->head, skb);
	298	return handle_tx(ser);
	299	}
	300
	301
	302	static void ldisc_tx_wakeup(struct tty_struct *tty)
	303	{
	304	struct ser_device *ser;
c1f8fc57	305
9b27105b SB	306	ser = tty->disc_data;
9b27105b SB	307	BUG_ON(ser == NULL);
f84ea779	308	WARN_ON(ser->tty != tty);
9b27105b SB	309	handle_tx(ser);
	310	}
	311
	312
	313	static int ldisc_open(struct tty_struct *tty)
	314	{
	315	struct ser_device *ser;
	316	struct net_device *dev;
	317	char name[64];
	318	int result;
	319
c93f0940 AC	320	/* No write no play */
	321	if (tty->ops->write == NULL)
	322	return -EOPNOTSUPP;
d3f744e0 SB	323	if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
d3f744e0 SB	324	return -EPERM;
c93f0940	325
9b27105b SB	326	sprintf(name, "cf%s", tty->name);
	327	dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
	328	ser = netdev_priv(dev);
e31d5a05	329	ser->tty = tty_kref_get(tty);
9b27105b SB	330	ser->dev = dev;
	331	debugfs_init(ser, tty);
	332	tty->receive_room = N_TTY_BUF_SIZE;
	333	tty->disc_data = ser;
	334	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
	335	rtnl_lock();
	336	result = register_netdevice(dev);
	337	if (result) {
	338	rtnl_unlock();
	339	free_netdev(dev);
	340	return -ENODEV;
	341	}
	342
	343	list_add(&ser->node, &ser_list);
	344	rtnl_unlock();
	345	netif_stop_queue(dev);
	346	update_tty_status(ser);
	347	return 0;
	348	}
	349
	350	static void ldisc_close(struct tty_struct *tty)
	351	{
	352	struct ser_device *ser = tty->disc_data;
	353	/* Remove may be called inside or outside of rtnl_lock */
	354	int islocked = rtnl_is_locked();
c1f8fc57	355
9b27105b SB	356	if (!islocked)
	357	rtnl_lock();
	358	/* device is freed automagically by net-sysfs */
	359	dev_close(ser->dev);
	360	unregister_netdevice(ser->dev);
	361	list_del(&ser->node);
	362	debugfs_deinit(ser);
e31d5a05	363	tty_kref_put(ser->tty);
9b27105b SB	364	if (!islocked)
	365	rtnl_unlock();
	366	}
	367
	368	/* The line discipline structure. */
	369	static struct tty_ldisc_ops caif_ldisc = {
	370	.owner = THIS_MODULE,
	371	.magic = TTY_LDISC_MAGIC,
	372	.name = "n_caif",
	373	.open = ldisc_open,
	374	.close = ldisc_close,
	375	.receive_buf = ldisc_receive,
	376	.write_wakeup = ldisc_tx_wakeup
	377	};
	378
	379	static int register_ldisc(void)
	380	{
	381	int result;
c1f8fc57	382
9b27105b SB	383	result = tty_register_ldisc(N_CAIF, &caif_ldisc);
	384	if (result < 0) {
	385	pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
	386	result);
	387	return result;
	388	}
	389	return result;
	390	}
	391	static const struct net_device_ops netdev_ops = {
	392	.ndo_open = caif_net_open,
	393	.ndo_stop = caif_net_close,
	394	.ndo_start_xmit = caif_xmit
	395	};
	396
	397	static void caifdev_setup(struct net_device *dev)
	398	{
	399	struct ser_device *serdev = netdev_priv(dev);
c1f8fc57	400
9b27105b SB	401	dev->features = 0;
	402	dev->netdev_ops = &netdev_ops;
	403	dev->type = ARPHRD_CAIF;
	404	dev->flags = IFF_POINTOPOINT \| IFF_NOARP;
	405	dev->mtu = CAIF_MAX_MTU;
9b27105b SB	406	dev->tx_queue_len = 0;
	407	dev->destructor = free_netdev;
	408	skb_queue_head_init(&serdev->head);
	409	serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
	410	serdev->common.use_frag = true;
	411	serdev->common.use_stx = ser_use_stx;
	412	serdev->common.use_fcs = ser_use_fcs;
	413	serdev->dev = dev;
	414	}
	415
	416
	417	static int caif_net_open(struct net_device *dev)
	418	{
9b27105b SB	419	netif_wake_queue(dev);
	420	return 0;
	421	}
	422
	423	static int caif_net_close(struct net_device *dev)
	424	{
	425	netif_stop_queue(dev);
	426	return 0;
	427	}
	428
	429	static int __init caif_ser_init(void)
	430	{
	431	int ret;
c1f8fc57	432
9b27105b SB	433	ret = register_ldisc();
	434	debugfsdir = debugfs_create_dir("caif_serial", NULL);
	435	return ret;
	436	}
	437
	438	static void __exit caif_ser_exit(void)
	439	{
	440	struct ser_device *ser = NULL;
	441	struct list_head *node;
	442	struct list_head *_tmp;
c1f8fc57	443
9b27105b SB	444	list_for_each_safe(node, _tmp, &ser_list) {
	445	ser = list_entry(node, struct ser_device, node);
	446	dev_close(ser->dev);
	447	unregister_netdevice(ser->dev);
	448	list_del(node);
	449	}
	450	tty_unregister_ldisc(N_CAIF);
	451	debugfs_remove_recursive(debugfsdir);
	452	}
	453
	454	module_init(caif_ser_init);
	455	module_exit(caif_ser_exit);