Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_TTY_PORT_H
3#define _LINUX_TTY_PORT_H
4
5#include <linux/kref.h>
6#include <linux/mutex.h>
7#include <linux/tty_buffer.h>
8#include <linux/wait.h>
9
10/*
11 * Port level information. Each device keeps its own port level information
12 * so provide a common structure for those ports wanting to use common support
13 * routines.
14 *
15 * The tty port has a different lifetime to the tty so must be kept apart.
16 * In addition be careful as tty -> port mappings are valid for the life
17 * of the tty object but in many cases port -> tty mappings are valid only
18 * until a hangup so don't use the wrong path.
19 */
20
21struct attribute_group;
22struct tty_driver;
23struct tty_port;
24struct tty_struct;
25
26struct tty_port_operations {
27 /* Return 1 if the carrier is raised */
28 int (*carrier_raised)(struct tty_port *port);
29 /* Control the DTR line */
30 void (*dtr_rts)(struct tty_port *port, int raise);
31 /* Called when the last close completes or a hangup finishes
32 IFF the port was initialized. Do not use to free resources. Called
33 under the port mutex to serialize against activate/shutdowns */
34 void (*shutdown)(struct tty_port *port);
35 /* Called under the port mutex from tty_port_open, serialized using
36 the port mutex */
37 /* FIXME: long term getting the tty argument *out* of this would be
38 good for consoles */
39 int (*activate)(struct tty_port *port, struct tty_struct *tty);
40 /* Called on the final put of a port */
41 void (*destruct)(struct tty_port *port);
42};
43
44struct tty_port_client_operations {
45 int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
46 void (*write_wakeup)(struct tty_port *port);
47};
48
49extern const struct tty_port_client_operations tty_port_default_client_ops;
50
51struct tty_port {
52 struct tty_bufhead buf; /* Locked internally */
53 struct tty_struct *tty; /* Back pointer */
54 struct tty_struct *itty; /* internal back ptr */
55 const struct tty_port_operations *ops; /* Port operations */
56 const struct tty_port_client_operations *client_ops; /* Port client operations */
57 spinlock_t lock; /* Lock protecting tty field */
58 int blocked_open; /* Waiting to open */
59 int count; /* Usage count */
60 wait_queue_head_t open_wait; /* Open waiters */
61 wait_queue_head_t delta_msr_wait; /* Modem status change */
62 unsigned long flags; /* User TTY flags ASYNC_ */
63 unsigned long iflags; /* Internal flags TTY_PORT_ */
64 unsigned char console:1; /* port is a console */
65 struct mutex mutex; /* Locking */
66 struct mutex buf_mutex; /* Buffer alloc lock */
67 unsigned char *xmit_buf; /* Optional buffer */
68 unsigned int close_delay; /* Close port delay */
69 unsigned int closing_wait; /* Delay for output */
70 int drain_delay; /* Set to zero if no pure time
71 based drain is needed else
72 set to size of fifo */
73 struct kref kref; /* Ref counter */
74 void *client_data;
75};
76
77/* tty_port::iflags bits -- use atomic bit ops */
78#define TTY_PORT_INITIALIZED 0 /* device is initialized */
79#define TTY_PORT_SUSPENDED 1 /* device is suspended */
80#define TTY_PORT_ACTIVE 2 /* device is open */
81
82/*
83 * uart drivers: use the uart_port::status field and the UPSTAT_* defines
84 * for s/w-based flow control steering and carrier detection status
85 */
86#define TTY_PORT_CTS_FLOW 3 /* h/w flow control enabled */
87#define TTY_PORT_CHECK_CD 4 /* carrier detect enabled */
88#define TTY_PORT_KOPENED 5 /* device exclusively opened by
89 kernel */
90
91void tty_port_init(struct tty_port *port);
92void tty_port_link_device(struct tty_port *port, struct tty_driver *driver,
93 unsigned index);
94struct device *tty_port_register_device(struct tty_port *port,
95 struct tty_driver *driver, unsigned index,
96 struct device *device);
97struct device *tty_port_register_device_attr(struct tty_port *port,
98 struct tty_driver *driver, unsigned index,
99 struct device *device, void *drvdata,
100 const struct attribute_group **attr_grp);
101struct device *tty_port_register_device_serdev(struct tty_port *port,
102 struct tty_driver *driver, unsigned index,
103 struct device *device);
104struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
105 struct tty_driver *driver, unsigned index,
106 struct device *device, void *drvdata,
107 const struct attribute_group **attr_grp);
108void tty_port_unregister_device(struct tty_port *port,
109 struct tty_driver *driver, unsigned index);
110int tty_port_alloc_xmit_buf(struct tty_port *port);
111void tty_port_free_xmit_buf(struct tty_port *port);
112void tty_port_destroy(struct tty_port *port);
113void tty_port_put(struct tty_port *port);
114
115static inline struct tty_port *tty_port_get(struct tty_port *port)
116{
117 if (port && kref_get_unless_zero(&port->kref))
118 return port;
119 return NULL;
120}
121
122/* If the cts flow control is enabled, return true. */
123static inline bool tty_port_cts_enabled(const struct tty_port *port)
124{
125 return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
126}
127
128static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
129{
130 assign_bit(TTY_PORT_CTS_FLOW, &port->iflags, val);
131}
132
133static inline bool tty_port_active(const struct tty_port *port)
134{
135 return test_bit(TTY_PORT_ACTIVE, &port->iflags);
136}
137
138static inline void tty_port_set_active(struct tty_port *port, bool val)
139{
140 assign_bit(TTY_PORT_ACTIVE, &port->iflags, val);
141}
142
143static inline bool tty_port_check_carrier(const struct tty_port *port)
144{
145 return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
146}
147
148static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
149{
150 assign_bit(TTY_PORT_CHECK_CD, &port->iflags, val);
151}
152
153static inline bool tty_port_suspended(const struct tty_port *port)
154{
155 return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
156}
157
158static inline void tty_port_set_suspended(struct tty_port *port, bool val)
159{
160 assign_bit(TTY_PORT_SUSPENDED, &port->iflags, val);
161}
162
163static inline bool tty_port_initialized(const struct tty_port *port)
164{
165 return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
166}
167
168static inline void tty_port_set_initialized(struct tty_port *port, bool val)
169{
170 assign_bit(TTY_PORT_INITIALIZED, &port->iflags, val);
171}
172
173static inline bool tty_port_kopened(const struct tty_port *port)
174{
175 return test_bit(TTY_PORT_KOPENED, &port->iflags);
176}
177
178static inline void tty_port_set_kopened(struct tty_port *port, bool val)
179{
180 assign_bit(TTY_PORT_KOPENED, &port->iflags, val);
181}
182
183struct tty_struct *tty_port_tty_get(struct tty_port *port);
184void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
185int tty_port_carrier_raised(struct tty_port *port);
186void tty_port_raise_dtr_rts(struct tty_port *port);
187void tty_port_lower_dtr_rts(struct tty_port *port);
188void tty_port_hangup(struct tty_port *port);
189void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
190void tty_port_tty_wakeup(struct tty_port *port);
191int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty,
192 struct file *filp);
193int tty_port_close_start(struct tty_port *port, struct tty_struct *tty,
194 struct file *filp);
195void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
196void tty_port_close(struct tty_port *port, struct tty_struct *tty,
197 struct file *filp);
198int tty_port_install(struct tty_port *port, struct tty_driver *driver,
199 struct tty_struct *tty);
200int tty_port_open(struct tty_port *port, struct tty_struct *tty,
201 struct file *filp);
202
203static inline int tty_port_users(struct tty_port *port)
204{
205 return port->count + port->blocked_open;
206}
207
208#endif