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3eb25fda MM |
1 | /* Generic serial interface functions. |
2 | ||
3 | Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, | |
4 | 2003, 2004, 2005 Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "serial.h" | |
25 | #include "ser-unix.h" | |
26 | #include "event-loop.h" | |
27 | ||
28 | static timer_handler_func push_event; | |
29 | static handler_func fd_event; | |
30 | ||
31 | /* Event handling for ASYNC serial code. | |
32 | ||
33 | At any time the SERIAL device either: has an empty FIFO and is | |
34 | waiting on a FD event; or has a non-empty FIFO/error condition and | |
35 | is constantly scheduling timer events. | |
36 | ||
37 | ASYNC only stops pestering its client when it is de-async'ed or it | |
38 | is told to go away. */ | |
39 | ||
40 | /* Value of scb->async_state: */ | |
41 | enum { | |
42 | /* >= 0 (TIMER_SCHEDULED) */ | |
43 | /* The ID of the currently scheduled timer event. This state is | |
44 | rarely encountered. Timer events are one-off so as soon as the | |
45 | event is delivered the state is shanged to NOTHING_SCHEDULED. */ | |
46 | FD_SCHEDULED = -1, | |
47 | /* The fd_event() handler is scheduled. It is called when ever the | |
48 | file descriptor becomes ready. */ | |
49 | NOTHING_SCHEDULED = -2 | |
50 | /* Either no task is scheduled (just going into ASYNC mode) or a | |
51 | timer event has just gone off and the current state has been | |
52 | forced into nothing scheduled. */ | |
53 | }; | |
54 | ||
55 | /* Identify and schedule the next ASYNC task based on scb->async_state | |
56 | and scb->buf* (the input FIFO). A state machine is used to avoid | |
57 | the need to make redundant calls into the event-loop - the next | |
58 | scheduled task is only changed when needed. */ | |
59 | ||
60 | void | |
61 | reschedule (struct serial *scb) | |
62 | { | |
63 | if (serial_is_async_p (scb)) | |
64 | { | |
65 | int next_state; | |
66 | switch (scb->async_state) | |
67 | { | |
68 | case FD_SCHEDULED: | |
69 | if (scb->bufcnt == 0) | |
70 | next_state = FD_SCHEDULED; | |
71 | else | |
72 | { | |
73 | delete_file_handler (scb->fd); | |
74 | next_state = create_timer (0, push_event, scb); | |
75 | } | |
76 | break; | |
77 | case NOTHING_SCHEDULED: | |
78 | if (scb->bufcnt == 0) | |
79 | { | |
80 | add_file_handler (scb->fd, fd_event, scb); | |
81 | next_state = FD_SCHEDULED; | |
82 | } | |
83 | else | |
84 | { | |
85 | next_state = create_timer (0, push_event, scb); | |
86 | } | |
87 | break; | |
88 | default: /* TIMER SCHEDULED */ | |
89 | if (scb->bufcnt == 0) | |
90 | { | |
91 | delete_timer (scb->async_state); | |
92 | add_file_handler (scb->fd, fd_event, scb); | |
93 | next_state = FD_SCHEDULED; | |
94 | } | |
95 | else | |
96 | next_state = scb->async_state; | |
97 | break; | |
98 | } | |
99 | if (serial_debug_p (scb)) | |
100 | { | |
101 | switch (next_state) | |
102 | { | |
103 | case FD_SCHEDULED: | |
104 | if (scb->async_state != FD_SCHEDULED) | |
105 | fprintf_unfiltered (gdb_stdlog, "[fd%d->fd-scheduled]\n", | |
106 | scb->fd); | |
107 | break; | |
108 | default: /* TIMER SCHEDULED */ | |
109 | if (scb->async_state == FD_SCHEDULED) | |
110 | fprintf_unfiltered (gdb_stdlog, "[fd%d->timer-scheduled]\n", | |
111 | scb->fd); | |
112 | break; | |
113 | } | |
114 | } | |
115 | scb->async_state = next_state; | |
116 | } | |
117 | } | |
118 | ||
119 | /* FD_EVENT: This is scheduled when the input FIFO is empty (and there | |
120 | is no pending error). As soon as data arrives, it is read into the | |
121 | input FIFO and the client notified. The client should then drain | |
122 | the FIFO using readchar(). If the FIFO isn't immediatly emptied, | |
123 | push_event() is used to nag the client until it is. */ | |
124 | ||
125 | static void | |
126 | fd_event (int error, void *context) | |
127 | { | |
128 | struct serial *scb = context; | |
129 | if (error != 0) | |
130 | { | |
131 | scb->bufcnt = SERIAL_ERROR; | |
132 | } | |
133 | else if (scb->bufcnt == 0) | |
134 | { | |
135 | /* Prime the input FIFO. The readchar() function is used to | |
136 | pull characters out of the buffer. See also | |
137 | generic_readchar(). */ | |
138 | int nr; | |
139 | do | |
140 | { | |
141 | nr = read (scb->fd, scb->buf, BUFSIZ); | |
142 | } | |
143 | while (nr == -1 && errno == EINTR); | |
144 | if (nr == 0) | |
145 | { | |
146 | scb->bufcnt = SERIAL_EOF; | |
147 | } | |
148 | else if (nr > 0) | |
149 | { | |
150 | scb->bufcnt = nr; | |
151 | scb->bufp = scb->buf; | |
152 | } | |
153 | else | |
154 | { | |
155 | scb->bufcnt = SERIAL_ERROR; | |
156 | } | |
157 | } | |
158 | scb->async_handler (scb, scb->async_context); | |
159 | reschedule (scb); | |
160 | } | |
161 | ||
162 | /* PUSH_EVENT: The input FIFO is non-empty (or there is a pending | |
163 | error). Nag the client until all the data has been read. In the | |
164 | case of errors, the client will need to close or de-async the | |
165 | device before naging stops. */ | |
166 | ||
167 | static void | |
168 | push_event (void *context) | |
169 | { | |
170 | struct serial *scb = context; | |
171 | scb->async_state = NOTHING_SCHEDULED; /* Timers are one-off */ | |
172 | scb->async_handler (scb, scb->async_context); | |
173 | /* re-schedule */ | |
174 | reschedule (scb); | |
175 | } | |
176 | ||
177 | int | |
dd5da072 | 178 | ser_base_write (struct serial *scb, const char *str, int len) |
3eb25fda MM |
179 | { |
180 | int cc; | |
181 | ||
182 | while (len > 0) | |
183 | { | |
184 | cc = write (scb->fd, str, len); | |
185 | ||
186 | if (cc < 0) | |
187 | return 1; | |
188 | len -= cc; | |
189 | str += cc; | |
190 | } | |
191 | return 0; | |
192 | } | |
193 | ||
194 | int | |
dd5da072 | 195 | ser_base_flush_output (struct serial *scb) |
3eb25fda MM |
196 | { |
197 | return 0; | |
198 | } | |
199 | ||
200 | int | |
dd5da072 | 201 | ser_base_flush_input (struct serial *scb) |
3eb25fda MM |
202 | { |
203 | if (scb->bufcnt >= 0) | |
204 | { | |
205 | scb->bufcnt = 0; | |
206 | scb->bufp = scb->buf; | |
207 | return 0; | |
208 | } | |
209 | else | |
210 | return SERIAL_ERROR; | |
211 | } | |
212 | ||
213 | int | |
dd5da072 | 214 | ser_base_send_break (struct serial *scb) |
3eb25fda MM |
215 | { |
216 | return 0; | |
217 | } | |
218 | ||
219 | int | |
dd5da072 | 220 | ser_base_drain_output (struct serial *scb) |
3eb25fda MM |
221 | { |
222 | return 0; | |
223 | } | |
224 | ||
225 | void | |
dd5da072 | 226 | ser_base_raw (struct serial *scb) |
3eb25fda MM |
227 | { |
228 | return; /* Always in raw mode */ | |
229 | } | |
230 | ||
231 | serial_ttystate | |
dd5da072 | 232 | ser_base_get_tty_state (struct serial *scb) |
3eb25fda MM |
233 | { |
234 | /* allocate a dummy */ | |
235 | return (serial_ttystate) XMALLOC (int); | |
236 | } | |
237 | ||
238 | int | |
dd5da072 | 239 | ser_base_set_tty_state (struct serial *scb, serial_ttystate ttystate) |
3eb25fda MM |
240 | { |
241 | return 0; | |
242 | } | |
243 | ||
244 | int | |
dd5da072 MM |
245 | ser_base_noflush_set_tty_state (struct serial *scb, |
246 | serial_ttystate new_ttystate, | |
247 | serial_ttystate old_ttystate) | |
3eb25fda MM |
248 | { |
249 | return 0; | |
250 | } | |
251 | ||
252 | void | |
dd5da072 MM |
253 | ser_base_print_tty_state (struct serial *scb, |
254 | serial_ttystate ttystate, | |
255 | struct ui_file *stream) | |
3eb25fda MM |
256 | { |
257 | /* Nothing to print. */ | |
258 | return; | |
259 | } | |
260 | ||
261 | int | |
dd5da072 | 262 | ser_base_setbaudrate (struct serial *scb, int rate) |
3eb25fda MM |
263 | { |
264 | return 0; /* Never fails! */ | |
265 | } | |
266 | ||
267 | int | |
dd5da072 | 268 | ser_base_setstopbits (struct serial *scb, int num) |
3eb25fda MM |
269 | { |
270 | return 0; /* Never fails! */ | |
271 | } | |
272 | ||
273 | /* Put the SERIAL device into/out-of ASYNC mode. */ | |
274 | ||
275 | void | |
dd5da072 | 276 | ser_base_async (struct serial *scb, |
3eb25fda MM |
277 | int async_p) |
278 | { | |
279 | if (async_p) | |
280 | { | |
281 | /* Force a re-schedule. */ | |
282 | scb->async_state = NOTHING_SCHEDULED; | |
283 | if (serial_debug_p (scb)) | |
284 | fprintf_unfiltered (gdb_stdlog, "[fd%d->asynchronous]\n", | |
285 | scb->fd); | |
286 | reschedule (scb); | |
287 | } | |
288 | else | |
289 | { | |
290 | if (serial_debug_p (scb)) | |
291 | fprintf_unfiltered (gdb_stdlog, "[fd%d->synchronous]\n", | |
292 | scb->fd); | |
293 | /* De-schedule whatever tasks are currently scheduled. */ | |
294 | switch (scb->async_state) | |
295 | { | |
296 | case FD_SCHEDULED: | |
297 | delete_file_handler (scb->fd); | |
298 | break; | |
299 | case NOTHING_SCHEDULED: | |
300 | break; | |
301 | default: /* TIMER SCHEDULED */ | |
302 | delete_timer (scb->async_state); | |
303 | break; | |
304 | } | |
305 | } | |
306 | } |