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67b94be4 JS |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_TTY_PORT_H | |
3 | #define _LINUX_TTY_PORT_H | |
4 | ||
4e2a44c1 | 5 | #include <linux/kfifo.h> |
67b94be4 JS |
6 | #include <linux/kref.h> |
7 | #include <linux/mutex.h> | |
8 | #include <linux/tty_buffer.h> | |
9 | #include <linux/wait.h> | |
10 | ||
67b94be4 JS |
11 | struct attribute_group; |
12 | struct tty_driver; | |
13 | struct tty_port; | |
14 | struct tty_struct; | |
15 | ||
630bf86d JS |
16 | /** |
17 | * struct tty_port_operations -- operations on tty_port | |
b300fb26 | 18 | * @carrier_raised: return true if the carrier is raised on @port |
5701cb8b | 19 | * @dtr_rts: raise the DTR line if @active is true, otherwise lower DTR |
630bf86d JS |
20 | * @shutdown: called when the last close completes or a hangup finishes IFF the |
21 | * port was initialized. Do not use to free resources. Turn off the device | |
22 | * only. Called under the port mutex to serialize against @activate and | |
23 | * @shutdown. | |
24 | * @activate: called under the port mutex from tty_port_open(), serialized using | |
25 | * the port mutex. Supposed to turn on the device. | |
26 | * | |
27 | * FIXME: long term getting the tty argument *out* of this would be good | |
28 | * for consoles. | |
29 | * | |
30 | * @destruct: called on the final put of a port. Free resources, possibly incl. | |
31 | * the port itself. | |
32 | */ | |
67b94be4 | 33 | struct tty_port_operations { |
b300fb26 | 34 | bool (*carrier_raised)(struct tty_port *port); |
5701cb8b | 35 | void (*dtr_rts)(struct tty_port *port, bool active); |
67b94be4 | 36 | void (*shutdown)(struct tty_port *port); |
67b94be4 | 37 | int (*activate)(struct tty_port *port, struct tty_struct *tty); |
67b94be4 JS |
38 | void (*destruct)(struct tty_port *port); |
39 | }; | |
40 | ||
41 | struct tty_port_client_operations { | |
42 | int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t); | |
6bb6fa69 IJ |
43 | void (*lookahead_buf)(struct tty_port *port, const unsigned char *cp, |
44 | const unsigned char *fp, unsigned int count); | |
67b94be4 JS |
45 | void (*write_wakeup)(struct tty_port *port); |
46 | }; | |
47 | ||
48 | extern const struct tty_port_client_operations tty_port_default_client_ops; | |
49 | ||
61c83add JS |
50 | /** |
51 | * struct tty_port -- port level information | |
52 | * | |
53 | * @buf: buffer for this port, locked internally | |
54 | * @tty: back pointer to &struct tty_struct, valid only if the tty is open. Use | |
55 | * tty_port_tty_get() to obtain it (and tty_kref_put() to release). | |
56 | * @itty: internal back pointer to &struct tty_struct. Avoid this. It should be | |
57 | * eliminated in the long term. | |
58 | * @ops: tty port operations (like activate, shutdown), see &struct | |
59 | * tty_port_operations | |
60 | * @client_ops: tty port client operations (like receive_buf, write_wakeup). | |
61 | * By default, tty_port_default_client_ops is used. | |
62 | * @lock: lock protecting @tty | |
63 | * @blocked_open: # of procs waiting for open in tty_port_block_til_ready() | |
64 | * @count: usage count | |
65 | * @open_wait: open waiters queue (waiting e.g. for a carrier) | |
66 | * @delta_msr_wait: modem status change queue (waiting for MSR changes) | |
67 | * @flags: user TTY flags (%ASYNC_) | |
68 | * @iflags: internal flags (%TTY_PORT_) | |
69 | * @console: when set, the port is a console | |
70 | * @mutex: locking, for open, shutdown and other port operations | |
71 | * @buf_mutex: @xmit_buf alloc lock | |
72 | * @xmit_buf: optional xmit buffer used by some drivers | |
4e2a44c1 | 73 | * @xmit_fifo: optional xmit buffer used by some drivers |
61c83add JS |
74 | * @close_delay: delay in jiffies to wait when closing the port |
75 | * @closing_wait: delay in jiffies for output to be sent before closing | |
76 | * @drain_delay: set to zero if no pure time based drain is needed else set to | |
77 | * size of fifo | |
78 | * @kref: references counter. Reaching zero calls @ops->destruct() if non-%NULL | |
79 | * or frees the port otherwise. | |
80 | * @client_data: pointer to private data, for @client_ops | |
81 | * | |
82 | * Each device keeps its own port level information. &struct tty_port was | |
83 | * introduced as a common structure for such information. As every TTY device | |
84 | * shall have a backing tty_port structure, every driver can use these members. | |
85 | * | |
86 | * The tty port has a different lifetime to the tty so must be kept apart. | |
87 | * In addition be careful as tty -> port mappings are valid for the life | |
88 | * of the tty object but in many cases port -> tty mappings are valid only | |
89 | * until a hangup so don't use the wrong path. | |
90 | * | |
91 | * Tty port shall be initialized by tty_port_init() and shut down either by | |
92 | * tty_port_destroy() (refcounting not used), or tty_port_put() (refcounting). | |
93 | * | |
94 | * There is a lot of helpers around &struct tty_port too. To name the most | |
95 | * significant ones: tty_port_open(), tty_port_close() (or | |
96 | * tty_port_close_start() and tty_port_close_end() separately if need be), and | |
97 | * tty_port_hangup(). These call @ops->activate() and @ops->shutdown() as | |
98 | * needed. | |
99 | */ | |
67b94be4 | 100 | struct tty_port { |
61c83add JS |
101 | struct tty_bufhead buf; |
102 | struct tty_struct *tty; | |
103 | struct tty_struct *itty; | |
104 | const struct tty_port_operations *ops; | |
105 | const struct tty_port_client_operations *client_ops; | |
106 | spinlock_t lock; | |
107 | int blocked_open; | |
108 | int count; | |
109 | wait_queue_head_t open_wait; | |
110 | wait_queue_head_t delta_msr_wait; | |
111 | unsigned long flags; | |
112 | unsigned long iflags; | |
113 | unsigned char console:1; | |
114 | struct mutex mutex; | |
115 | struct mutex buf_mutex; | |
116 | unsigned char *xmit_buf; | |
4e2a44c1 | 117 | DECLARE_KFIFO_PTR(xmit_fifo, unsigned char); |
61c83add JS |
118 | unsigned int close_delay; |
119 | unsigned int closing_wait; | |
120 | int drain_delay; | |
121 | struct kref kref; | |
122 | void *client_data; | |
67b94be4 JS |
123 | }; |
124 | ||
125 | /* tty_port::iflags bits -- use atomic bit ops */ | |
126 | #define TTY_PORT_INITIALIZED 0 /* device is initialized */ | |
127 | #define TTY_PORT_SUSPENDED 1 /* device is suspended */ | |
128 | #define TTY_PORT_ACTIVE 2 /* device is open */ | |
129 | ||
130 | /* | |
131 | * uart drivers: use the uart_port::status field and the UPSTAT_* defines | |
132 | * for s/w-based flow control steering and carrier detection status | |
133 | */ | |
134 | #define TTY_PORT_CTS_FLOW 3 /* h/w flow control enabled */ | |
135 | #define TTY_PORT_CHECK_CD 4 /* carrier detect enabled */ | |
136 | #define TTY_PORT_KOPENED 5 /* device exclusively opened by | |
137 | kernel */ | |
138 | ||
139 | void tty_port_init(struct tty_port *port); | |
140 | void tty_port_link_device(struct tty_port *port, struct tty_driver *driver, | |
141 | unsigned index); | |
142 | struct device *tty_port_register_device(struct tty_port *port, | |
143 | struct tty_driver *driver, unsigned index, | |
144 | struct device *device); | |
145 | struct device *tty_port_register_device_attr(struct tty_port *port, | |
146 | struct tty_driver *driver, unsigned index, | |
147 | struct device *device, void *drvdata, | |
148 | const struct attribute_group **attr_grp); | |
149 | struct device *tty_port_register_device_serdev(struct tty_port *port, | |
150 | struct tty_driver *driver, unsigned index, | |
151 | struct device *device); | |
152 | struct device *tty_port_register_device_attr_serdev(struct tty_port *port, | |
153 | struct tty_driver *driver, unsigned index, | |
154 | struct device *device, void *drvdata, | |
155 | const struct attribute_group **attr_grp); | |
156 | void tty_port_unregister_device(struct tty_port *port, | |
157 | struct tty_driver *driver, unsigned index); | |
158 | int tty_port_alloc_xmit_buf(struct tty_port *port); | |
159 | void tty_port_free_xmit_buf(struct tty_port *port); | |
160 | void tty_port_destroy(struct tty_port *port); | |
161 | void tty_port_put(struct tty_port *port); | |
162 | ||
163 | static inline struct tty_port *tty_port_get(struct tty_port *port) | |
164 | { | |
165 | if (port && kref_get_unless_zero(&port->kref)) | |
166 | return port; | |
167 | return NULL; | |
168 | } | |
169 | ||
170 | /* If the cts flow control is enabled, return true. */ | |
171 | static inline bool tty_port_cts_enabled(const struct tty_port *port) | |
172 | { | |
173 | return test_bit(TTY_PORT_CTS_FLOW, &port->iflags); | |
174 | } | |
175 | ||
176 | static inline void tty_port_set_cts_flow(struct tty_port *port, bool val) | |
177 | { | |
178 | assign_bit(TTY_PORT_CTS_FLOW, &port->iflags, val); | |
179 | } | |
180 | ||
181 | static inline bool tty_port_active(const struct tty_port *port) | |
182 | { | |
183 | return test_bit(TTY_PORT_ACTIVE, &port->iflags); | |
184 | } | |
185 | ||
186 | static inline void tty_port_set_active(struct tty_port *port, bool val) | |
187 | { | |
188 | assign_bit(TTY_PORT_ACTIVE, &port->iflags, val); | |
189 | } | |
190 | ||
191 | static inline bool tty_port_check_carrier(const struct tty_port *port) | |
192 | { | |
193 | return test_bit(TTY_PORT_CHECK_CD, &port->iflags); | |
194 | } | |
195 | ||
196 | static inline void tty_port_set_check_carrier(struct tty_port *port, bool val) | |
197 | { | |
198 | assign_bit(TTY_PORT_CHECK_CD, &port->iflags, val); | |
199 | } | |
200 | ||
201 | static inline bool tty_port_suspended(const struct tty_port *port) | |
202 | { | |
203 | return test_bit(TTY_PORT_SUSPENDED, &port->iflags); | |
204 | } | |
205 | ||
206 | static inline void tty_port_set_suspended(struct tty_port *port, bool val) | |
207 | { | |
208 | assign_bit(TTY_PORT_SUSPENDED, &port->iflags, val); | |
209 | } | |
210 | ||
211 | static inline bool tty_port_initialized(const struct tty_port *port) | |
212 | { | |
213 | return test_bit(TTY_PORT_INITIALIZED, &port->iflags); | |
214 | } | |
215 | ||
216 | static inline void tty_port_set_initialized(struct tty_port *port, bool val) | |
217 | { | |
218 | assign_bit(TTY_PORT_INITIALIZED, &port->iflags, val); | |
219 | } | |
220 | ||
221 | static inline bool tty_port_kopened(const struct tty_port *port) | |
222 | { | |
223 | return test_bit(TTY_PORT_KOPENED, &port->iflags); | |
224 | } | |
225 | ||
226 | static inline void tty_port_set_kopened(struct tty_port *port, bool val) | |
227 | { | |
228 | assign_bit(TTY_PORT_KOPENED, &port->iflags, val); | |
229 | } | |
230 | ||
231 | struct tty_struct *tty_port_tty_get(struct tty_port *port); | |
232 | void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty); | |
b300fb26 | 233 | bool tty_port_carrier_raised(struct tty_port *port); |
67b94be4 JS |
234 | void tty_port_raise_dtr_rts(struct tty_port *port); |
235 | void tty_port_lower_dtr_rts(struct tty_port *port); | |
236 | void tty_port_hangup(struct tty_port *port); | |
237 | void tty_port_tty_hangup(struct tty_port *port, bool check_clocal); | |
238 | void tty_port_tty_wakeup(struct tty_port *port); | |
239 | int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty, | |
240 | struct file *filp); | |
241 | int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, | |
242 | struct file *filp); | |
243 | void tty_port_close_end(struct tty_port *port, struct tty_struct *tty); | |
244 | void tty_port_close(struct tty_port *port, struct tty_struct *tty, | |
245 | struct file *filp); | |
246 | int tty_port_install(struct tty_port *port, struct tty_driver *driver, | |
247 | struct tty_struct *tty); | |
248 | int tty_port_open(struct tty_port *port, struct tty_struct *tty, | |
249 | struct file *filp); | |
250 | ||
251 | static inline int tty_port_users(struct tty_port *port) | |
252 | { | |
253 | return port->count + port->blocked_open; | |
254 | } | |
255 | ||
256 | #endif |