1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/types.h> |
3 | #include <linux/tty.h> |
4 | #include <linux/tty_flip.h> |
5 | #include <linux/slab.h> |
6 | |
7 | #include "speakup.h" |
8 | #include "spk_types.h" |
9 | #include "spk_priv.h" |
10 | |
11 | struct spk_ldisc_data { |
12 | char buf; |
13 | struct completion completion; |
14 | bool buf_free; |
15 | struct spk_synth *synth; |
16 | }; |
17 | |
18 | /* |
19 | * This allows to catch within spk_ttyio_ldisc_open whether it is getting set |
20 | * on for a speakup-driven device. |
21 | */ |
22 | static struct tty_struct *speakup_tty; |
23 | /* This mutex serializes the use of such global speakup_tty variable */ |
24 | static DEFINE_MUTEX(speakup_tty_mutex); |
25 | |
26 | static int ser_to_dev(int ser, dev_t *dev_no) |
27 | { |
28 | if (ser < 0 || ser > (255 - 64)) { |
29 | pr_err("speakup: Invalid ser param. Must be between 0 and 191 inclusive.\n" ); |
30 | return -EINVAL; |
31 | } |
32 | |
33 | *dev_no = MKDEV(4, (64 + ser)); |
34 | return 0; |
35 | } |
36 | |
37 | static int get_dev_to_use(struct spk_synth *synth, dev_t *dev_no) |
38 | { |
39 | /* use ser only when dev is not specified */ |
40 | if (strcmp(synth->dev_name, SYNTH_DEFAULT_DEV) || |
41 | synth->ser == SYNTH_DEFAULT_SER) |
42 | return tty_dev_name_to_number(name: synth->dev_name, number: dev_no); |
43 | |
44 | return ser_to_dev(ser: synth->ser, dev_no); |
45 | } |
46 | |
47 | static int spk_ttyio_ldisc_open(struct tty_struct *tty) |
48 | { |
49 | struct spk_ldisc_data *ldisc_data; |
50 | |
51 | if (tty != speakup_tty) |
52 | /* Somebody tried to use this line discipline outside speakup */ |
53 | return -ENODEV; |
54 | |
55 | if (!tty->ops->write) |
56 | return -EOPNOTSUPP; |
57 | |
58 | ldisc_data = kmalloc(size: sizeof(*ldisc_data), GFP_KERNEL); |
59 | if (!ldisc_data) |
60 | return -ENOMEM; |
61 | |
62 | init_completion(x: &ldisc_data->completion); |
63 | ldisc_data->buf_free = true; |
64 | tty->disc_data = ldisc_data; |
65 | |
66 | return 0; |
67 | } |
68 | |
69 | static void spk_ttyio_ldisc_close(struct tty_struct *tty) |
70 | { |
71 | kfree(objp: tty->disc_data); |
72 | } |
73 | |
74 | static size_t spk_ttyio_receive_buf2(struct tty_struct *tty, const u8 *cp, |
75 | const u8 *fp, size_t count) |
76 | { |
77 | struct spk_ldisc_data *ldisc_data = tty->disc_data; |
78 | struct spk_synth *synth = ldisc_data->synth; |
79 | |
80 | if (synth->read_buff_add) { |
81 | unsigned int i; |
82 | |
83 | for (i = 0; i < count; i++) |
84 | synth->read_buff_add(cp[i]); |
85 | |
86 | return count; |
87 | } |
88 | |
89 | if (!ldisc_data->buf_free) |
90 | /* ttyio_in will tty_flip_buffer_push */ |
91 | return 0; |
92 | |
93 | /* Make sure the consumer has read buf before we have seen |
94 | * buf_free == true and overwrite buf |
95 | */ |
96 | mb(); |
97 | |
98 | ldisc_data->buf = cp[0]; |
99 | ldisc_data->buf_free = false; |
100 | complete(&ldisc_data->completion); |
101 | |
102 | return 1; |
103 | } |
104 | |
105 | static struct tty_ldisc_ops spk_ttyio_ldisc_ops = { |
106 | .owner = THIS_MODULE, |
107 | .num = N_SPEAKUP, |
108 | .name = "speakup_ldisc" , |
109 | .open = spk_ttyio_ldisc_open, |
110 | .close = spk_ttyio_ldisc_close, |
111 | .receive_buf2 = spk_ttyio_receive_buf2, |
112 | }; |
113 | |
114 | static int spk_ttyio_out(struct spk_synth *in_synth, const char ch); |
115 | static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch); |
116 | static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch); |
117 | static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear); |
118 | static unsigned char spk_ttyio_in(struct spk_synth *in_synth); |
119 | static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth); |
120 | static void spk_ttyio_flush_buffer(struct spk_synth *in_synth); |
121 | static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth); |
122 | |
123 | struct spk_io_ops spk_ttyio_ops = { |
124 | .synth_out = spk_ttyio_out, |
125 | .synth_out_unicode = spk_ttyio_out_unicode, |
126 | .send_xchar = spk_ttyio_send_xchar, |
127 | .tiocmset = spk_ttyio_tiocmset, |
128 | .synth_in = spk_ttyio_in, |
129 | .synth_in_nowait = spk_ttyio_in_nowait, |
130 | .flush_buffer = spk_ttyio_flush_buffer, |
131 | .wait_for_xmitr = spk_ttyio_wait_for_xmitr, |
132 | }; |
133 | EXPORT_SYMBOL_GPL(spk_ttyio_ops); |
134 | |
135 | static inline void get_termios(struct tty_struct *tty, |
136 | struct ktermios *out_termios) |
137 | { |
138 | down_read(sem: &tty->termios_rwsem); |
139 | *out_termios = tty->termios; |
140 | up_read(sem: &tty->termios_rwsem); |
141 | } |
142 | |
143 | static int spk_ttyio_initialise_ldisc(struct spk_synth *synth) |
144 | { |
145 | int ret = 0; |
146 | struct tty_struct *tty; |
147 | struct ktermios tmp_termios; |
148 | dev_t dev; |
149 | |
150 | ret = get_dev_to_use(synth, dev_no: &dev); |
151 | if (ret) |
152 | return ret; |
153 | |
154 | tty = tty_kopen_exclusive(device: dev); |
155 | if (IS_ERR(ptr: tty)) |
156 | return PTR_ERR(ptr: tty); |
157 | |
158 | if (tty->ops->open) |
159 | ret = tty->ops->open(tty, NULL); |
160 | else |
161 | ret = -ENODEV; |
162 | |
163 | if (ret) { |
164 | tty_unlock(tty); |
165 | return ret; |
166 | } |
167 | |
168 | clear_bit(TTY_HUPPED, addr: &tty->flags); |
169 | /* ensure hardware flow control is enabled */ |
170 | get_termios(tty, out_termios: &tmp_termios); |
171 | if (!(tmp_termios.c_cflag & CRTSCTS)) { |
172 | tmp_termios.c_cflag |= CRTSCTS; |
173 | tty_set_termios(tty, kt: &tmp_termios); |
174 | /* |
175 | * check c_cflag to see if it's updated as tty_set_termios |
176 | * may not return error even when no tty bits are |
177 | * changed by the request. |
178 | */ |
179 | get_termios(tty, out_termios: &tmp_termios); |
180 | if (!(tmp_termios.c_cflag & CRTSCTS)) |
181 | pr_warn("speakup: Failed to set hardware flow control\n" ); |
182 | } |
183 | |
184 | tty_unlock(tty); |
185 | |
186 | mutex_lock(&speakup_tty_mutex); |
187 | speakup_tty = tty; |
188 | ret = tty_set_ldisc(tty, N_SPEAKUP); |
189 | speakup_tty = NULL; |
190 | mutex_unlock(lock: &speakup_tty_mutex); |
191 | |
192 | if (!ret) { |
193 | /* Success */ |
194 | struct spk_ldisc_data *ldisc_data = tty->disc_data; |
195 | |
196 | ldisc_data->synth = synth; |
197 | synth->dev = tty; |
198 | return 0; |
199 | } |
200 | |
201 | pr_err("speakup: Failed to set N_SPEAKUP on tty\n" ); |
202 | |
203 | tty_lock(tty); |
204 | if (tty->ops->close) |
205 | tty->ops->close(tty, NULL); |
206 | tty_unlock(tty); |
207 | |
208 | tty_kclose(tty); |
209 | |
210 | return ret; |
211 | } |
212 | |
213 | void spk_ttyio_register_ldisc(void) |
214 | { |
215 | if (tty_register_ldisc(new_ldisc: &spk_ttyio_ldisc_ops)) |
216 | pr_warn("speakup: Error registering line discipline. Most synths won't work.\n" ); |
217 | } |
218 | |
219 | void spk_ttyio_unregister_ldisc(void) |
220 | { |
221 | tty_unregister_ldisc(ldisc: &spk_ttyio_ldisc_ops); |
222 | } |
223 | |
224 | static int spk_ttyio_out(struct spk_synth *in_synth, const char ch) |
225 | { |
226 | struct tty_struct *tty = in_synth->dev; |
227 | int ret; |
228 | |
229 | if (!in_synth->alive || !tty->ops->write) |
230 | return 0; |
231 | |
232 | ret = tty->ops->write(tty, &ch, 1); |
233 | |
234 | if (ret == 0) |
235 | /* No room */ |
236 | return 0; |
237 | |
238 | if (ret > 0) |
239 | /* Success */ |
240 | return 1; |
241 | |
242 | pr_warn("%s: I/O error, deactivating speakup\n" , |
243 | in_synth->long_name); |
244 | /* No synth any more, so nobody will restart TTYs, |
245 | * and we thus need to do it ourselves. Now that there |
246 | * is no synth we can let application flood anyway |
247 | */ |
248 | in_synth->alive = 0; |
249 | speakup_start_ttys(); |
250 | return 0; |
251 | } |
252 | |
253 | static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch) |
254 | { |
255 | int ret; |
256 | |
257 | if (ch < 0x80) { |
258 | ret = spk_ttyio_out(in_synth, ch); |
259 | } else if (ch < 0x800) { |
260 | ret = spk_ttyio_out(in_synth, ch: 0xc0 | (ch >> 6)); |
261 | ret &= spk_ttyio_out(in_synth, ch: 0x80 | (ch & 0x3f)); |
262 | } else { |
263 | ret = spk_ttyio_out(in_synth, ch: 0xe0 | (ch >> 12)); |
264 | ret &= spk_ttyio_out(in_synth, ch: 0x80 | ((ch >> 6) & 0x3f)); |
265 | ret &= spk_ttyio_out(in_synth, ch: 0x80 | (ch & 0x3f)); |
266 | } |
267 | return ret; |
268 | } |
269 | |
270 | static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch) |
271 | { |
272 | struct tty_struct *tty = in_synth->dev; |
273 | |
274 | if (tty->ops->send_xchar) |
275 | tty->ops->send_xchar(tty, ch); |
276 | } |
277 | |
278 | static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear) |
279 | { |
280 | struct tty_struct *tty = in_synth->dev; |
281 | |
282 | if (tty->ops->tiocmset) |
283 | tty->ops->tiocmset(tty, set, clear); |
284 | } |
285 | |
286 | static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth) |
287 | { |
288 | return 1; |
289 | } |
290 | |
291 | static unsigned char ttyio_in(struct spk_synth *in_synth, int timeout) |
292 | { |
293 | struct tty_struct *tty = in_synth->dev; |
294 | struct spk_ldisc_data *ldisc_data = tty->disc_data; |
295 | char rv; |
296 | |
297 | if (!timeout) { |
298 | if (!try_wait_for_completion(x: &ldisc_data->completion)) |
299 | return 0xff; |
300 | } else if (wait_for_completion_timeout(x: &ldisc_data->completion, |
301 | timeout: usecs_to_jiffies(u: timeout)) == 0) { |
302 | pr_warn("spk_ttyio: timeout (%d) while waiting for input\n" , |
303 | timeout); |
304 | return 0xff; |
305 | } |
306 | |
307 | rv = ldisc_data->buf; |
308 | /* Make sure we have read buf before we set buf_free to let |
309 | * the producer overwrite it |
310 | */ |
311 | mb(); |
312 | ldisc_data->buf_free = true; |
313 | /* Let TTY push more characters */ |
314 | tty_flip_buffer_push(port: tty->port); |
315 | |
316 | return rv; |
317 | } |
318 | |
319 | static unsigned char spk_ttyio_in(struct spk_synth *in_synth) |
320 | { |
321 | return ttyio_in(in_synth, SPK_SYNTH_TIMEOUT); |
322 | } |
323 | |
324 | static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth) |
325 | { |
326 | u8 rv = ttyio_in(in_synth, timeout: 0); |
327 | |
328 | return (rv == 0xff) ? 0 : rv; |
329 | } |
330 | |
331 | static void spk_ttyio_flush_buffer(struct spk_synth *in_synth) |
332 | { |
333 | struct tty_struct *tty = in_synth->dev; |
334 | |
335 | if (tty->ops->flush_buffer) |
336 | tty->ops->flush_buffer(tty); |
337 | } |
338 | |
339 | int spk_ttyio_synth_probe(struct spk_synth *synth) |
340 | { |
341 | int rv = spk_ttyio_initialise_ldisc(synth); |
342 | |
343 | if (rv) |
344 | return rv; |
345 | |
346 | synth->alive = 1; |
347 | |
348 | return 0; |
349 | } |
350 | EXPORT_SYMBOL_GPL(spk_ttyio_synth_probe); |
351 | |
352 | void spk_ttyio_release(struct spk_synth *in_synth) |
353 | { |
354 | struct tty_struct *tty = in_synth->dev; |
355 | |
356 | if (tty == NULL) |
357 | return; |
358 | |
359 | tty_lock(tty); |
360 | |
361 | if (tty->ops->close) |
362 | tty->ops->close(tty, NULL); |
363 | |
364 | tty_ldisc_flush(tty); |
365 | tty_unlock(tty); |
366 | tty_kclose(tty); |
367 | |
368 | in_synth->dev = NULL; |
369 | } |
370 | EXPORT_SYMBOL_GPL(spk_ttyio_release); |
371 | |
372 | const char *spk_ttyio_synth_immediate(struct spk_synth *in_synth, const char *buff) |
373 | { |
374 | struct tty_struct *tty = in_synth->dev; |
375 | u_char ch; |
376 | |
377 | while ((ch = *buff)) { |
378 | if (ch == '\n') |
379 | ch = in_synth->procspeech; |
380 | if (tty_write_room(tty) < 1 || |
381 | !in_synth->io_ops->synth_out(in_synth, ch)) |
382 | return buff; |
383 | buff++; |
384 | } |
385 | return NULL; |
386 | } |
387 | EXPORT_SYMBOL_GPL(spk_ttyio_synth_immediate); |
388 | |