1 files changed, 56 insertions, 11 deletions

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index c3f9d93ba227..1d21a9c1d33e 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -11,11 +11,50 @@
 #include <linux/timer.h>
 #include <linux/string.h>
 #include <linux/slab.h>
-#include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/serdev.h>
+
+static int tty_port_default_receive_buf(struct tty_port *port,
+					const unsigned char *p,
+					const unsigned char *f, size_t count)
+{
+	int ret;
+	struct tty_struct *tty;
+	struct tty_ldisc *disc;
+
+	tty = READ_ONCE(port->itty);
+	if (!tty)
+		return 0;
+
+	disc = tty_ldisc_ref(tty);
+	if (!disc)
+		return 0;
+
+	ret = tty_ldisc_receive_buf(disc, p, (char *)f, count);
+
+	tty_ldisc_deref(disc);
+
+	return ret;
+}
+
+static void tty_port_default_wakeup(struct tty_port *port)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty) {
+		tty_wakeup(tty);
+		tty_kref_put(tty);
+	}
+}
+
+static const struct tty_port_client_operations default_client_ops = {
+	.receive_buf = tty_port_default_receive_buf,
+	.write_wakeup = tty_port_default_wakeup,
+};
 
 void tty_port_init(struct tty_port *port)
 {
@@ -28,6 +67,7 @@ void tty_port_init(struct tty_port *port)
 	spin_lock_init(&port->lock);
 	port->close_delay = (50 * HZ) / 100;
 	port->closing_wait = (3000 * HZ) / 100;
+	port->client_ops = &default_client_ops;
 	kref_init(&port->kref);
 }
 EXPORT_SYMBOL(tty_port_init);
@@ -67,8 +107,7 @@ struct device *tty_port_register_device(struct tty_port *port,
 		struct tty_driver *driver, unsigned index,
 		struct device *device)
 {
-	tty_port_link_device(port, driver, index);
-	return tty_register_device(driver, index, device);
+	return tty_port_register_device_attr(port, driver, index, device, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(tty_port_register_device);
 
@@ -90,7 +129,15 @@ struct device *tty_port_register_device_attr(struct tty_port *port,
 		struct device *device, void *drvdata,
 		const struct attribute_group **attr_grp)
 {
+	struct device *dev;
+
 	tty_port_link_device(port, driver, index);
+
+	dev = serdev_tty_port_register(port, device, driver, index);
+	if (PTR_ERR(dev) != -ENODEV)
+		/* Skip creating cdev if we registered a serdev device */
+		return dev;
+
 	return tty_register_device_attr(driver, index, device, drvdata,
 			attr_grp);
 }
@@ -142,6 +189,9 @@ static void tty_port_destructor(struct kref *kref)
 	/* check if last port ref was dropped before tty release */
 	if (WARN_ON(port->itty))
 		return;
+
+	serdev_tty_port_unregister(port);
+
 	if (port->xmit_buf)
 		free_page((unsigned long)port->xmit_buf);
 	tty_port_destroy(port);
@@ -273,12 +323,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
  */
 void tty_port_tty_wakeup(struct tty_port *port)
 {
-	struct tty_struct *tty = tty_port_tty_get(port);
-
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+	port->client_ops->write_wakeup(port);
 }
 EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
 
@@ -335,7 +380,7 @@ EXPORT_SYMBOL(tty_port_lower_dtr_rts);
  *	tty_port_block_til_ready	-	Waiting logic for tty open
  *	@port: the tty port being opened
  *	@tty: the tty device being bound
- *	@filp: the file pointer of the opener
+ *	@filp: the file pointer of the opener or NULL
  *
  *	Implement the core POSIX/SuS tty behaviour when opening a tty device.
  *	Handles:
@@ -369,7 +414,7 @@ int tty_port_block_til_ready(struct tty_port *port,
 		tty_port_set_active(port, 1);
 		return 0;
 	}
-	if (filp->f_flags & O_NONBLOCK) {
+	if (filp == NULL || (filp->f_flags & O_NONBLOCK)) {
 		/* Indicate we are open */
 		if (C_BAUD(tty))
 			tty_port_raise_dtr_rts(port);