1 files changed, 309 insertions, 0 deletions
diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
new file mode 100644
index 0000000000..1db3f30011
--- /dev/null
+++ b/drivers/input/serio/serport.c
@@ -0,0 +1,309 @@
+// 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;
+	unsigned long flags;
+
+	spin_lock_irqsave(&serport->lock, flags);
+	set_bit(SERPORT_ACTIVE, &serport->flags);
+	spin_unlock_irqrestore(&serport->lock, flags);
+
+	return 0;
+}
+
+
+static void serport_serio_close(struct serio *serio)
+{
+	struct serport *serport = serio->port_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&serport->lock, flags);
+	clear_bit(SERPORT_ACTIVE, &serport->flags);
+	spin_unlock_irqrestore(&serport->lock, 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(struct 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 long flags;
+	unsigned int ch_flags = 0;
+	int i;
+
+	spin_lock_irqsave(&serport->lock, flags);
+
+	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+		goto out;
+
+	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);
+	}
+
+out:
+	spin_unlock_irqrestore(&serport->lock, 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(struct 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;
+	unsigned long flags;
+
+	spin_lock_irqsave(&serport->lock, flags);
+	set_bit(SERPORT_DEAD, &serport->flags);
+	spin_unlock_irqrestore(&serport->lock, flags);
+
+	wake_up_interruptible(&serport->wait);
+}
+
+static void serport_ldisc_write_wakeup(struct tty_struct * tty)
+{
+	struct serport *serport = tty->disc_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&serport->lock, flags);
+	if (test_bit(SERPORT_ACTIVE, &serport->flags))
+		serio_drv_write_wakeup(serport->serio);
+	spin_unlock_irqrestore(&serport->lock, flags);
+}
+
+/*
+ * 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);