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 21 struct attribute_group; 22 struct tty_driver; 23 struct tty_port; 24 struct tty_struct; 25 26 struct 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 44 struct 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 49 extern const struct tty_port_client_operations tty_port_default_client_ops; 50 51 struct 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 91 void tty_port_init(struct tty_port *port); 92 void tty_port_link_device(struct tty_port *port, struct tty_driver *driver, 93 unsigned index); 94 struct device *tty_port_register_device(struct tty_port *port, 95 struct tty_driver *driver, unsigned index, 96 struct device *device); 97 struct 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); 101 struct device *tty_port_register_device_serdev(struct tty_port *port, 102 struct tty_driver *driver, unsigned index, 103 struct device *device); 104 struct 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); 108 void tty_port_unregister_device(struct tty_port *port, 109 struct tty_driver *driver, unsigned index); 110 int tty_port_alloc_xmit_buf(struct tty_port *port); 111 void tty_port_free_xmit_buf(struct tty_port *port); 112 void tty_port_destroy(struct tty_port *port); 113 void tty_port_put(struct tty_port *port); 114 115 static 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. */ 123 static inline bool tty_port_cts_enabled(const struct tty_port *port) 124 { 125 return test_bit(TTY_PORT_CTS_FLOW, &port->iflags); 126 } 127 128 static 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 } 132 133 static inline bool tty_port_active(const struct tty_port *port) 134 { 135 return test_bit(TTY_PORT_ACTIVE, &port->iflags); 136 } 137 138 static inline void tty_port_set_active(struct tty_port *port, bool val) 139 { 140 assign_bit(TTY_PORT_ACTIVE, &port->iflags, val); 141 } 142 143 static inline bool tty_port_check_carrier(const struct tty_port *port) 144 { 145 return test_bit(TTY_PORT_CHECK_CD, &port->iflags); 146 } 147 148 static 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 } 152 153 static inline bool tty_port_suspended(const struct tty_port *port) 154 { 155 return test_bit(TTY_PORT_SUSPENDED, &port->iflags); 156 } 157 158 static inline void tty_port_set_suspended(struct tty_port *port, bool val) 159 { 160 assign_bit(TTY_PORT_SUSPENDED, &port->iflags, val); 161 } 162 163 static inline bool tty_port_initialized(const struct tty_port *port) 164 { 165 return test_bit(TTY_PORT_INITIALIZED, &port->iflags); 166 } 167 168 static inline void tty_port_set_initialized(struct tty_port *port, bool val) 169 { 170 assign_bit(TTY_PORT_INITIALIZED, &port->iflags, val); 171 } 172 173 static inline bool tty_port_kopened(const struct tty_port *port) 174 { 175 return test_bit(TTY_PORT_KOPENED, &port->iflags); 176 } 177 178 static inline void tty_port_set_kopened(struct tty_port *port, bool val) 179 { 180 assign_bit(TTY_PORT_KOPENED, &port->iflags, val); 181 } 182 183 struct tty_struct *tty_port_tty_get(struct tty_port *port); 184 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty); 185 int tty_port_carrier_raised(struct tty_port *port); 186 void tty_port_raise_dtr_rts(struct tty_port *port); 187 void tty_port_lower_dtr_rts(struct tty_port *port); 188 void tty_port_hangup(struct tty_port *port); 189 void tty_port_tty_hangup(struct tty_port *port, bool check_clocal); 190 void tty_port_tty_wakeup(struct tty_port *port); 191 int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty, 192 struct file *filp); 193 int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, 194 struct file *filp); 195 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty); 196 void tty_port_close(struct tty_port *port, struct tty_struct *tty, 197 struct file *filp); 198 int tty_port_install(struct tty_port *port, struct tty_driver *driver, 199 struct tty_struct *tty); 200 int tty_port_open(struct tty_port *port, struct tty_struct *tty, 201 struct file *filp); 202 203 static inline int tty_port_users(struct tty_port *port) 204 { 205 return port->count + port->blocked_open; 206 } 207 208 #endif 209