tty: move tty_port to new tty_port.h

tty.h is long enough already. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_port.h and move there tty_port-related
declarations and function prototypes (those implemented in tty_port.c).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 208 insertions, 0 deletions

diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
new file mode 100644
index 000000000000..6e86e9e118b6
--- /dev/null
+++ b/include/linux/tty_port.h
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TTY_PORT_H
+#define _LINUX_TTY_PORT_H
+
+#include <linux/kref.h>
+#include <linux/mutex.h>
+#include <linux/tty_buffer.h>
+#include <linux/wait.h>
+
+/*
+ * Port level information. Each device keeps its own port level information
+ * so provide a common structure for those ports wanting to use common support
+ * routines.
+ *
+ * The tty port has a different lifetime to the tty so must be kept apart.
+ * In addition be careful as tty -> port mappings are valid for the life
+ * of the tty object but in many cases port -> tty mappings are valid only
+ * until a hangup so don't use the wrong path.
+ */
+
+struct attribute_group;
+struct tty_driver;
+struct tty_port;
+struct tty_struct;
+
+struct tty_port_operations {
+	/* Return 1 if the carrier is raised */
+	int (*carrier_raised)(struct tty_port *port);
+	/* Control the DTR line */
+	void (*dtr_rts)(struct tty_port *port, int raise);
+	/* Called when the last close completes or a hangup finishes
+	   IFF the port was initialized. Do not use to free resources. Called
+	   under the port mutex to serialize against activate/shutdowns */
+	void (*shutdown)(struct tty_port *port);
+	/* Called under the port mutex from tty_port_open, serialized using
+	   the port mutex */
+        /* FIXME: long term getting the tty argument *out* of this would be
+           good for consoles */
+	int (*activate)(struct tty_port *port, struct tty_struct *tty);
+	/* Called on the final put of a port */
+	void (*destruct)(struct tty_port *port);
+};
+
+struct tty_port_client_operations {
+	int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
+	void (*write_wakeup)(struct tty_port *port);
+};
+
+extern const struct tty_port_client_operations tty_port_default_client_ops;
+
+struct tty_port {
+	struct tty_bufhead	buf;		/* Locked internally */
+	struct tty_struct	*tty;		/* Back pointer */
+	struct tty_struct	*itty;		/* internal back ptr */
+	const struct tty_port_operations *ops;	/* Port operations */
+	const struct tty_port_client_operations *client_ops; /* Port client operations */
+	spinlock_t		lock;		/* Lock protecting tty field */
+	int			blocked_open;	/* Waiting to open */
+	int			count;		/* Usage count */
+	wait_queue_head_t	open_wait;	/* Open waiters */
+	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
+	unsigned long		flags;		/* User TTY flags ASYNC_ */
+	unsigned long		iflags;		/* Internal flags TTY_PORT_ */
+	unsigned char		console:1;	/* port is a console */
+	struct mutex		mutex;		/* Locking */
+	struct mutex		buf_mutex;	/* Buffer alloc lock */
+	unsigned char		*xmit_buf;	/* Optional buffer */
+	unsigned int		close_delay;	/* Close port delay */
+	unsigned int		closing_wait;	/* Delay for output */
+	int			drain_delay;	/* Set to zero if no pure time
+						   based drain is needed else
+						   set to size of fifo */
+	struct kref		kref;		/* Ref counter */
+	void 			*client_data;
+};
+
+/* tty_port::iflags bits -- use atomic bit ops */
+#define TTY_PORT_INITIALIZED	0	/* device is initialized */
+#define TTY_PORT_SUSPENDED	1	/* device is suspended */
+#define TTY_PORT_ACTIVE		2	/* device is open */
+
+/*
+ * uart drivers: use the uart_port::status field and the UPSTAT_* defines
+ * for s/w-based flow control steering and carrier detection status
+ */
+#define TTY_PORT_CTS_FLOW	3	/* h/w flow control enabled */
+#define TTY_PORT_CHECK_CD	4	/* carrier detect enabled */
+#define TTY_PORT_KOPENED	5	/* device exclusively opened by
+					   kernel */
+
+void tty_port_init(struct tty_port *port);
+void tty_port_link_device(struct tty_port *port, struct tty_driver *driver,
+		unsigned index);
+struct device *tty_port_register_device(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device);
+struct device *tty_port_register_device_attr(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device, void *drvdata,
+		const struct attribute_group **attr_grp);
+struct device *tty_port_register_device_serdev(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device);
+struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device, void *drvdata,
+		const struct attribute_group **attr_grp);
+void tty_port_unregister_device(struct tty_port *port,
+		struct tty_driver *driver, unsigned index);
+int tty_port_alloc_xmit_buf(struct tty_port *port);
+void tty_port_free_xmit_buf(struct tty_port *port);
+void tty_port_destroy(struct tty_port *port);
+void tty_port_put(struct tty_port *port);
+
+static inline struct tty_port *tty_port_get(struct tty_port *port)
+{
+	if (port && kref_get_unless_zero(&port->kref))
+		return port;
+	return NULL;
+}
+
+/* If the cts flow control is enabled, return true. */
+static inline bool tty_port_cts_enabled(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
+}
+
+static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_CTS_FLOW, &port->iflags, val);
+}
+
+static inline bool tty_port_active(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_ACTIVE, &port->iflags);
+}
+
+static inline void tty_port_set_active(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_ACTIVE, &port->iflags, val);
+}
+
+static inline bool tty_port_check_carrier(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
+}
+
+static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_CHECK_CD, &port->iflags, val);
+}
+
+static inline bool tty_port_suspended(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
+}
+
+static inline void tty_port_set_suspended(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_SUSPENDED, &port->iflags, val);
+}
+
+static inline bool tty_port_initialized(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
+}
+
+static inline void tty_port_set_initialized(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_INITIALIZED, &port->iflags, val);
+}
+
+static inline bool tty_port_kopened(const struct tty_port *port)
+{
+	return test_bit(TTY_PORT_KOPENED, &port->iflags);
+}
+
+static inline void tty_port_set_kopened(struct tty_port *port, bool val)
+{
+	assign_bit(TTY_PORT_KOPENED, &port->iflags, val);
+}
+
+struct tty_struct *tty_port_tty_get(struct tty_port *port);
+void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
+int tty_port_carrier_raised(struct tty_port *port);
+void tty_port_raise_dtr_rts(struct tty_port *port);
+void tty_port_lower_dtr_rts(struct tty_port *port);
+void tty_port_hangup(struct tty_port *port);
+void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
+void tty_port_tty_wakeup(struct tty_port *port);
+int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty,
+		struct file *filp);
+int tty_port_close_start(struct tty_port *port, struct tty_struct *tty,
+		struct file *filp);
+void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
+void tty_port_close(struct tty_port *port, struct tty_struct *tty,
+		struct file *filp);
+int tty_port_install(struct tty_port *port, struct tty_driver *driver,
+		struct tty_struct *tty);
+int tty_port_open(struct tty_port *port, struct tty_struct *tty,
+		struct file *filp);
+
+static inline int tty_port_users(struct tty_port *port)
+{
+	return port->count + port->blocked_open;
+}
+
+#endif