[linux-2.6-block.git] / drivers / input / serio / serport.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Input device TTY line discipline
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 *
 * This is a module that converts a tty line into a much simpler
 * 'serial io port' abstraction that the input device drivers use.
 */


#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/tty.h>
#include <linux/compat.h>

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Input device TTY line discipline");
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_MOUSE);

#define SERPORT_BUSY	1
#define SERPORT_ACTIVE	2
#define SERPORT_DEAD	3

struct serport {
	struct tty_struct *tty;
	wait_queue_head_t wait;
	struct serio *serio;
	struct serio_device_id id;
	spinlock_t lock;
	unsigned long flags;
};

/*
 * Callback functions from the serio code.
 */

static int serport_serio_write(struct serio *serio, unsigned char data)
{
	struct serport *serport = serio->port_data;
	return -(serport->tty->ops->write(serport->tty, &data, 1) != 1);
}

static int serport_serio_open(struct serio *serio)
{
	struct serport *serport = serio->port_data;

	guard(spinlock_irqsave)(&serport->lock);
	set_bit(SERPORT_ACTIVE, &serport->flags);

	return 0;
}


static void serport_serio_close(struct serio *serio)
{
	struct serport *serport = serio->port_data;

	guard(spinlock_irqsave)(&serport->lock);
	clear_bit(SERPORT_ACTIVE, &serport->flags);
}

/*
 * serport_ldisc_open() is the routine that is called upon setting our line
 * discipline on a tty. It prepares the serio struct.
 */

static int serport_ldisc_open(struct tty_struct *tty)
{
	struct serport *serport;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	serport = kzalloc(sizeof(*serport), GFP_KERNEL);
	if (!serport)
		return -ENOMEM;

	serport->tty = tty;
	spin_lock_init(&serport->lock);
	init_waitqueue_head(&serport->wait);

	tty->disc_data = serport;
	tty->receive_room = 256;
	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);

	return 0;
}

/*
 * serport_ldisc_close() is the opposite of serport_ldisc_open()
 */

static void serport_ldisc_close(struct tty_struct *tty)
{
	struct serport *serport = tty->disc_data;

	kfree(serport);
}

/*
 * serport_ldisc_receive() is called by the low level tty driver when characters
 * are ready for us. We forward the characters and flags, one by one to the
 * 'interrupt' routine.
 */

static void serport_ldisc_receive(struct tty_struct *tty, const u8 *cp,
				  const u8 *fp, size_t count)
{
	struct serport *serport = tty->disc_data;
	unsigned int ch_flags = 0;
	int i;

	guard(spinlock_irqsave)(&serport->lock);

	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
		return;

	for (i = 0; i < count; i++) {
		if (fp) {
			switch (fp[i]) {
			case TTY_FRAME:
				ch_flags = SERIO_FRAME;
				break;

			case TTY_PARITY:
				ch_flags = SERIO_PARITY;
				break;

			default:
				ch_flags = 0;
				break;
			}
		}

		serio_interrupt(serport->serio, cp[i], ch_flags);
	}
}

/*
 * serport_ldisc_read() just waits indefinitely if everything goes well.
 * However, when the serio driver closes the serio port, it finishes,
 * returning 0 characters.
 */

static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file,
				  u8 *kbuf, size_t nr, void **cookie,
				  unsigned long offset)
{
	struct serport *serport = tty->disc_data;
	struct serio *serio;

	if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
		return -EBUSY;

	serport->serio = serio = kzalloc(sizeof(*serio), GFP_KERNEL);
	if (!serio)
		return -ENOMEM;

	strscpy(serio->name, "Serial port", sizeof(serio->name));
	snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
	serio->id = serport->id;
	serio->id.type = SERIO_RS232;
	serio->write = serport_serio_write;
	serio->open = serport_serio_open;
	serio->close = serport_serio_close;
	serio->port_data = serport;
	serio->dev.parent = tty->dev;

	serio_register_port(serport->serio);
	printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty));

	wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
	serio_unregister_port(serport->serio);
	serport->serio = NULL;

	clear_bit(SERPORT_DEAD, &serport->flags);
	clear_bit(SERPORT_BUSY, &serport->flags);

	return 0;
}

static void serport_set_type(struct tty_struct *tty, unsigned long type)
{
	struct serport *serport = tty->disc_data;

	serport->id.proto = type & 0x000000ff;
	serport->id.id    = (type & 0x0000ff00) >> 8;
	serport->id.extra = (type & 0x00ff0000) >> 16;
}

/*
 * serport_ldisc_ioctl() allows to set the port protocol, and device ID
 */

static int serport_ldisc_ioctl(struct tty_struct *tty, unsigned int cmd,
			       unsigned long arg)
{
	if (cmd == SPIOCSTYPE) {
		unsigned long type;

		if (get_user(type, (unsigned long __user *) arg))
			return -EFAULT;

		serport_set_type(tty, type);
		return 0;
	}

	return -EINVAL;
}

#ifdef CONFIG_COMPAT
#define COMPAT_SPIOCSTYPE	_IOW('q', 0x01, compat_ulong_t)
static int serport_ldisc_compat_ioctl(struct tty_struct *tty,
				       unsigned int cmd, unsigned long arg)
{
	if (cmd == COMPAT_SPIOCSTYPE) {
		void __user *uarg = compat_ptr(arg);
		compat_ulong_t compat_type;

		if (get_user(compat_type, (compat_ulong_t __user *)uarg))
			return -EFAULT;

		serport_set_type(tty, compat_type);
		return 0;
	}

	return -EINVAL;
}
#endif

static void serport_ldisc_hangup(struct tty_struct *tty)
{
	struct serport *serport = tty->disc_data;

	scoped_guard(spinlock_irqsave, &serport->lock)
		set_bit(SERPORT_DEAD, &serport->flags);

	wake_up_interruptible(&serport->wait);
}

static void serport_ldisc_write_wakeup(struct tty_struct * tty)
{
	struct serport *serport = tty->disc_data;

	guard(spinlock_irqsave)(&serport->lock);

	if (test_bit(SERPORT_ACTIVE, &serport->flags))
		serio_drv_write_wakeup(serport->serio);
}

/*
 * The line discipline structure.
 */

static struct tty_ldisc_ops serport_ldisc = {
	.owner =	THIS_MODULE,
	.num =		N_MOUSE,
	.name =		"input",
	.open =		serport_ldisc_open,
	.close =	serport_ldisc_close,
	.read =		serport_ldisc_read,
	.ioctl =	serport_ldisc_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl =	serport_ldisc_compat_ioctl,
#endif
	.receive_buf =	serport_ldisc_receive,
	.hangup =	serport_ldisc_hangup,
	.write_wakeup =	serport_ldisc_write_wakeup
};

/*
 * The functions for insering/removing us as a module.
 */

static int __init serport_init(void)
{
	int retval;
	retval = tty_register_ldisc(&serport_ldisc);
	if (retval)
		printk(KERN_ERR "serport.c: Error registering line discipline.\n");

	return  retval;
}

static void __exit serport_exit(void)
{
	tty_unregister_ldisc(&serport_ldisc);
}

module_init(serport_init);
module_exit(serport_exit);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	/*
	3	* Input device TTY line discipline
	4	*
	5	* Copyright (c) 1999-2002 Vojtech Pavlik
	6	*
	7	* This is a module that converts a tty line into a much simpler
	8	* 'serial io port' abstraction that the input device drivers use.
	9	*/
	10
1da177e4	11
7c0f6ba6	12	#include <linux/uaccess.h>
1da177e4	13	#include <linux/kernel.h>
d43c36dc	14	#include <linux/sched.h>
1da177e4 LT	15	#include <linux/slab.h>
	16	#include <linux/module.h>
	17	#include <linux/init.h>
	18	#include <linux/serio.h>
	19	#include <linux/tty.h>
a80d8b02	20	#include <linux/compat.h>
1da177e4 LT	21
	22	MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
	23	MODULE_DESCRIPTION("Input device TTY line discipline");
	24	MODULE_LICENSE("GPL");
	25	MODULE_ALIAS_LDISC(N_MOUSE);
	26
	27	#define SERPORT_BUSY 1
1ff2c873 DT	28	#define SERPORT_ACTIVE 2
1ff2c873 DT	29	#define SERPORT_DEAD 3
1da177e4 LT	30
	31	struct serport {
	32	struct tty_struct *tty;
	33	wait_queue_head_t wait;
	34	struct serio *serio;
1ff2c873 DT	35	struct serio_device_id id;
1ff2c873 DT	36	spinlock_t lock;
1da177e4 LT	37	unsigned long flags;
	38	};
	39
	40	/*
	41	* Callback functions from the serio code.
	42	*/
	43
	44	static int serport_serio_write(struct serio *serio, unsigned char data)
	45	{
	46	struct serport *serport = serio->port_data;
f34d7a5b	47	return -(serport->tty->ops->write(serport->tty, &data, 1) != 1);
1da177e4 LT	48	}
1da177e4 LT	49
1ff2c873 DT	50	static int serport_serio_open(struct serio *serio)
	51	{
	52	struct serport *serport = serio->port_data;
1ff2c873	53
f7d15dcc	54	guard(spinlock_irqsave)(&serport->lock);
1ff2c873	55	set_bit(SERPORT_ACTIVE, &serport->flags);
1ff2c873 DT	56
	57	return 0;
	58	}
	59
	60
1da177e4 LT	61	static void serport_serio_close(struct serio *serio)
	62	{
	63	struct serport *serport = serio->port_data;
1ff2c873	64
f7d15dcc	65	guard(spinlock_irqsave)(&serport->lock);
1ff2c873	66	clear_bit(SERPORT_ACTIVE, &serport->flags);
1da177e4 LT	67	}
	68
	69	/*
	70	* serport_ldisc_open() is the routine that is called upon setting our line
	71	* discipline on a tty. It prepares the serio struct.
	72	*/
	73
	74	static int serport_ldisc_open(struct tty_struct *tty)
	75	{
	76	struct serport *serport;
1da177e4 LT	77
	78	if (!capable(CAP_SYS_ADMIN))
	79	return -EPERM;
	80
06b449d7	81	serport = kzalloc(sizeof(*serport), GFP_KERNEL);
1ff2c873	82	if (!serport)
1da177e4	83	return -ENOMEM;
1da177e4	84
1da177e4	85	serport->tty = tty;
1ff2c873	86	spin_lock_init(&serport->lock);
1da177e4 LT	87	init_waitqueue_head(&serport->wait);
1da177e4 LT	88
1ff2c873	89	tty->disc_data = serport;
33f0f88f	90	tty->receive_room = 256;
1ff2c873 DT	91	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
1ff2c873 DT	92
1da177e4 LT	93	return 0;
	94	}
	95
	96	/*
	97	* serport_ldisc_close() is the opposite of serport_ldisc_open()
	98	*/
	99
	100	static void serport_ldisc_close(struct tty_struct *tty)
	101	{
ca1a8d2f	102	struct serport *serport = tty->disc_data;
1ff2c873	103
1da177e4 LT	104	kfree(serport);
	105	}
	106
	107	/*
	108	* serport_ldisc_receive() is called by the low level tty driver when characters
48c27016 DE	109	* are ready for us. We forward the characters and flags, one by one to the
48c27016 DE	110	* 'interrupt' routine.
1da177e4 LT	111	*/
1da177e4 LT	112
a8d9cd23	113	static void serport_ldisc_receive(struct tty_struct tty, const u8 cp,
892bc209	114	const u8 *fp, size_t count)
1da177e4	115	{
ca1a8d2f	116	struct serport *serport = tty->disc_data;
82f91fe0	117	unsigned int ch_flags = 0;
1da177e4	118	int i;
1ff2c873	119
f7d15dcc	120	guard(spinlock_irqsave)(&serport->lock);
1ff2c873	121
55db4c64	122	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
f7d15dcc	123	return;
1ff2c873	124
48c27016	125	for (i = 0; i < count; i++) {
82f91fe0 PH	126	if (fp) {
	127	switch (fp[i]) {
	128	case TTY_FRAME:
	129	ch_flags = SERIO_FRAME;
	130	break;
	131
	132	case TTY_PARITY:
	133	ch_flags = SERIO_PARITY;
	134	break;
	135
	136	default:
	137	ch_flags = 0;
	138	break;
	139	}
48c27016 DE	140	}
	141
	142	serio_interrupt(serport->serio, cp[i], ch_flags);
	143	}
1da177e4 LT	144	}
1da177e4 LT	145
1da177e4 LT	146	/*
	147	* serport_ldisc_read() just waits indefinitely if everything goes well.
	148	* However, when the serio driver closes the serio port, it finishes,
	149	* returning 0 characters.
	150	*/
	151
3b830a9c	152	static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file,
49b8220c JSS	153	u8 kbuf, size_t nr, void *cookie,
49b8220c JSS	154	unsigned long offset)
1da177e4	155	{
ca1a8d2f	156	struct serport *serport = tty->disc_data;
1ff2c873	157	struct serio *serio;
1da177e4 LT	158
	159	if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
	160	return -EBUSY;
	161
06b449d7	162	serport->serio = serio = kzalloc(sizeof(*serio), GFP_KERNEL);
1ff2c873 DT	163	if (!serio)
	164	return -ENOMEM;
	165
a9f08ad7	166	strscpy(serio->name, "Serial port", sizeof(serio->name));
429b4749	167	snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
1ff2c873 DT	168	serio->id = serport->id;
	169	serio->id.type = SERIO_RS232;
	170	serio->write = serport_serio_write;
	171	serio->open = serport_serio_open;
	172	serio->close = serport_serio_close;
	173	serio->port_data = serport;
de838a93	174	serio->dev.parent = tty->dev;
1ff2c873	175
1da177e4	176	serio_register_port(serport->serio);
429b4749	177	printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty));
1ff2c873 DT	178
1ff2c873 DT	179	wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
1da177e4	180	serio_unregister_port(serport->serio);
1ff2c873	181	serport->serio = NULL;
1da177e4	182
1ff2c873	183	clear_bit(SERPORT_DEAD, &serport->flags);
1da177e4 LT	184	clear_bit(SERPORT_BUSY, &serport->flags);
	185
	186	return 0;
	187	}
	188
a80d8b02 JS	189	static void serport_set_type(struct tty_struct *tty, unsigned long type)
	190	{
	191	struct serport *serport = tty->disc_data;
	192
	193	serport->id.proto = type & 0x000000ff;
	194	serport->id.id = (type & 0x0000ff00) >> 8;
	195	serport->id.extra = (type & 0x00ff0000) >> 16;
	196	}
	197
1da177e4 LT	198	/*
	199	* serport_ldisc_ioctl() allows to set the port protocol, and device ID
	200	*/
	201
d78328bc JS	202	static int serport_ldisc_ioctl(struct tty_struct *tty, unsigned int cmd,
d78328bc JS	203	unsigned long arg)
1da177e4	204	{
1da177e4	205	if (cmd == SPIOCSTYPE) {
a80d8b02 JS	206	unsigned long type;
a80d8b02 JS	207
1da177e4 LT	208	if (get_user(type, (unsigned long __user *) arg))
	209	return -EFAULT;
	210
a80d8b02 JS	211	serport_set_type(tty, type);
	212	return 0;
	213	}
	214
	215	return -EINVAL;
	216	}
	217
	218	#ifdef CONFIG_COMPAT
	219	#define COMPAT_SPIOCSTYPE _IOW('q', 0x01, compat_ulong_t)
f0193d3e	220	static int serport_ldisc_compat_ioctl(struct tty_struct *tty,
a80d8b02 JS	221	unsigned int cmd, unsigned long arg)
	222	{
	223	if (cmd == COMPAT_SPIOCSTYPE) {
	224	void __user *uarg = compat_ptr(arg);
	225	compat_ulong_t compat_type;
	226
	227	if (get_user(compat_type, (compat_ulong_t __user *)uarg))
	228	return -EFAULT;
1da177e4	229
a80d8b02	230	serport_set_type(tty, compat_type);
1da177e4 LT	231	return 0;
	232	}
	233
	234	return -EINVAL;
	235	}
a80d8b02	236	#endif
1da177e4	237
28f194da	238	static void serport_ldisc_hangup(struct tty_struct *tty)
51db0137	239	{
ca1a8d2f	240	struct serport *serport = tty->disc_data;
51db0137	241
f7d15dcc DT	242	scoped_guard(spinlock_irqsave, &serport->lock)
f7d15dcc DT	243	set_bit(SERPORT_DEAD, &serport->flags);
51db0137 HV	244
51db0137 HV	245	wake_up_interruptible(&serport->wait);
51db0137 HV	246	}
51db0137 HV	247
1da177e4 LT	248	static void serport_ldisc_write_wakeup(struct tty_struct * tty)
1da177e4 LT	249	{
ca1a8d2f	250	struct serport *serport = tty->disc_data;
1da177e4	251
f7d15dcc DT	252	guard(spinlock_irqsave)(&serport->lock);
f7d15dcc DT	253
1ff2c873 DT	254	if (test_bit(SERPORT_ACTIVE, &serport->flags))
1ff2c873 DT	255	serio_drv_write_wakeup(serport->serio);
1da177e4 LT	256	}
	257
	258	/*
	259	* The line discipline structure.
	260	*/
	261
a352def2	262	static struct tty_ldisc_ops serport_ldisc = {
1da177e4	263	.owner = THIS_MODULE,
fbadf70a	264	.num = N_MOUSE,
1da177e4 LT	265	.name = "input",
	266	.open = serport_ldisc_open,
	267	.close = serport_ldisc_close,
	268	.read = serport_ldisc_read,
	269	.ioctl = serport_ldisc_ioctl,
a80d8b02 JS	270	#ifdef CONFIG_COMPAT
	271	.compat_ioctl = serport_ldisc_compat_ioctl,
	272	#endif
1da177e4	273	.receive_buf = serport_ldisc_receive,
51db0137	274	.hangup = serport_ldisc_hangup,
1da177e4 LT	275	.write_wakeup = serport_ldisc_write_wakeup
	276	};
	277
	278	/*
	279	* The functions for insering/removing us as a module.
	280	*/
	281
	282	static int __init serport_init(void)
	283	{
	284	int retval;
fbadf70a	285	retval = tty_register_ldisc(&serport_ldisc);
1da177e4 LT	286	if (retval)
	287	printk(KERN_ERR "serport.c: Error registering line discipline.\n");
	288
	289	return retval;
	290	}
	291
	292	static void __exit serport_exit(void)
	293	{
f81ee8b8	294	tty_unregister_ldisc(&serport_ldisc);
1da177e4 LT	295	}
	296
	297	module_init(serport_init);
	298	module_exit(serport_exit);