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authorAlan Cox <alan@redhat.com>2008-07-16 16:53:41 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-20 20:12:35 -0400
commit6f67048cd010afe19d79d821f16055d9c704c6f0 (patch)
tree1fbd4717f97632a4753ea98555e285483e35cd45 /include/linux/tty.h
parentd87a6d951c6c09d191d9c10903deb3cc353fcd2c (diff)
tty: Introduce a tty_port common structure
Every tty driver has its own concept of a port structure and because they all differ we cannot extract commonality. Begin fixing this by creating a structure drivers can elect to use so that over time we can push fields into this and create commonality and then introduce common methods. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/tty.h')
-rw-r--r--include/linux/tty.h30
1 files changed, 29 insertions, 1 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 013711ea7385..d7c695b65c0e 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -166,6 +166,29 @@ struct tty_bufhead {
166 166
167struct device; 167struct device;
168struct signal_struct; 168struct signal_struct;
169
170/*
171 * Port level information. Each device keeps its own port level information
172 * so provide a common structure for those ports wanting to use common support
173 * routines.
174 *
175 * The tty port has a different lifetime to the tty so must be kept apart.
176 * In addition be careful as tty -> port mappings are valid for the life
177 * of the tty object but in many cases port -> tty mappings are valid only
178 * until a hangup so don't use the wrong path.
179 */
180
181struct tty_port {
182 struct tty_struct *tty; /* Back pointer */
183 int blocked_open; /* Waiting to open */
184 int count; /* Usage count */
185 wait_queue_head_t open_wait; /* Open waiters */
186 wait_queue_head_t close_wait; /* Close waiters */
187 unsigned long flags; /* TTY flags ASY_*/
188 struct mutex mutex; /* Locking */
189 unsigned char *xmit_buf; /* Optional buffer */
190};
191
169/* 192/*
170 * Where all of the state associated with a tty is kept while the tty 193 * Where all of the state associated with a tty is kept while the tty
171 * is open. Since the termios state should be kept even if the tty 194 * is open. Since the termios state should be kept even if the tty
@@ -214,7 +237,7 @@ struct tty_struct {
214 struct list_head tty_files; 237 struct list_head tty_files;
215 238
216#define N_TTY_BUF_SIZE 4096 239#define N_TTY_BUF_SIZE 4096
217 240
218 /* 241 /*
219 * The following is data for the N_TTY line discipline. For 242 * The following is data for the N_TTY line discipline. For
220 * historical reasons, this is included in the tty structure. 243 * historical reasons, this is included in the tty structure.
@@ -242,6 +265,7 @@ struct tty_struct {
242 spinlock_t read_lock; 265 spinlock_t read_lock;
243 /* If the tty has a pending do_SAK, queue it here - akpm */ 266 /* If the tty has a pending do_SAK, queue it here - akpm */
244 struct work_struct SAK_work; 267 struct work_struct SAK_work;
268 struct tty_port *port;
245}; 269};
246 270
247/* tty magic number */ 271/* tty magic number */
@@ -350,6 +374,10 @@ extern void tty_write_unlock(struct tty_struct *tty);
350extern int tty_write_lock(struct tty_struct *tty, int ndelay); 374extern int tty_write_lock(struct tty_struct *tty, int ndelay);
351#define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock)) 375#define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock))
352 376
377extern void tty_port_init(struct tty_port *port);
378extern int tty_port_alloc_xmit_buf(struct tty_port *port);
379extern void tty_port_free_xmit_buf(struct tty_port *port);
380
353 381
354 382
355/* n_tty.c */ 383/* n_tty.c */