1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/interrupt.h>
3 #include <linux/ioport.h>
4 
5 #include "spk_types.h"
6 #include "speakup.h"
7 #include "spk_priv.h"
8 #include "serialio.h"
9 
10 #include <linux/serial_core.h>
11 /* WARNING:  Do not change this to <linux/serial.h> without testing that
12  * SERIAL_PORT_DFNS does get defined to the appropriate value.
13  */
14 #include <asm/serial.h>
15 
16 #ifndef SERIAL_PORT_DFNS
17 #define SERIAL_PORT_DFNS
18 #endif
19 
20 static void start_serial_interrupt(int irq);
21 
22 static const struct old_serial_port rs_table[] = {
23 	SERIAL_PORT_DFNS
24 };
25 
26 static const struct old_serial_port *serstate;
27 static int timeouts;
28 
29 static int spk_serial_out(struct spk_synth *in_synth, const char ch);
30 static void spk_serial_send_xchar(char ch);
31 static void spk_serial_tiocmset(unsigned int set, unsigned int clear);
32 static unsigned char spk_serial_in(void);
33 static unsigned char spk_serial_in_nowait(void);
34 static void spk_serial_flush_buffer(void);
35 static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth);
36 
37 struct spk_io_ops spk_serial_io_ops = {
38 	.synth_out = spk_serial_out,
39 	.send_xchar = spk_serial_send_xchar,
40 	.tiocmset = spk_serial_tiocmset,
41 	.synth_in = spk_serial_in,
42 	.synth_in_nowait = spk_serial_in_nowait,
43 	.flush_buffer = spk_serial_flush_buffer,
44 	.wait_for_xmitr = spk_serial_wait_for_xmitr,
45 };
46 EXPORT_SYMBOL_GPL(spk_serial_io_ops);
47 
48 const struct old_serial_port *spk_serial_init(int index)
49 {
50 	int baud = 9600, quot = 0;
51 	unsigned int cval = 0;
52 	int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
53 	const struct old_serial_port *ser;
54 	int err;
55 
56 	if (index >= ARRAY_SIZE(rs_table)) {
57 		pr_info("no port info for ttyS%d\n", index);
58 		return NULL;
59 	}
60 	ser = rs_table + index;
61 
62 	/*	Divisor, bytesize and parity */
63 	quot = ser->baud_base / baud;
64 	cval = cflag & (CSIZE | CSTOPB);
65 #if defined(__powerpc__) || defined(__alpha__)
66 	cval >>= 8;
67 #else /* !__powerpc__ && !__alpha__ */
68 	cval >>= 4;
69 #endif /* !__powerpc__ && !__alpha__ */
70 	if (cflag & PARENB)
71 		cval |= UART_LCR_PARITY;
72 	if (!(cflag & PARODD))
73 		cval |= UART_LCR_EPAR;
74 	if (synth_request_region(ser->port, 8)) {
75 		/* try to take it back. */
76 		pr_info("Ports not available, trying to steal them\n");
77 		__release_region(&ioport_resource, ser->port, 8);
78 		err = synth_request_region(ser->port, 8);
79 		if (err) {
80 			pr_warn("Unable to allocate port at %x, errno %i",
81 				ser->port, err);
82 			return NULL;
83 		}
84 	}
85 
86 	/*	Disable UART interrupts, set DTR and RTS high
87 	 *	and set speed.
88 	 */
89 	outb(cval | UART_LCR_DLAB, ser->port + UART_LCR);	/* set DLAB */
90 	outb(quot & 0xff, ser->port + UART_DLL);	/* LS of divisor */
91 	outb(quot >> 8, ser->port + UART_DLM);		/* MS of divisor */
92 	outb(cval, ser->port + UART_LCR);		/* reset DLAB */
93 
94 	/* Turn off Interrupts */
95 	outb(0, ser->port + UART_IER);
96 	outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);
97 
98 	/* If we read 0xff from the LSR, there is no UART here. */
99 	if (inb(ser->port + UART_LSR) == 0xff) {
100 		synth_release_region(ser->port, 8);
101 		serstate = NULL;
102 		return NULL;
103 	}
104 
105 	mdelay(1);
106 	speakup_info.port_tts = ser->port;
107 	serstate = ser;
108 
109 	start_serial_interrupt(ser->irq);
110 
111 	return ser;
112 }
113 
114 static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
115 {
116 	unsigned long flags;
117 	int c;
118 
119 	spin_lock_irqsave(&speakup_info.spinlock, flags);
120 	while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {
121 		c = inb_p(speakup_info.port_tts + UART_RX);
122 		synth->read_buff_add((u_char)c);
123 	}
124 	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
125 	return IRQ_HANDLED;
126 }
127 
128 static void start_serial_interrupt(int irq)
129 {
130 	int rv;
131 
132 	if (!synth->read_buff_add)
133 		return;
134 
135 	rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
136 			 "serial", (void *)synth_readbuf_handler);
137 
138 	if (rv)
139 		pr_err("Unable to request Speakup serial I R Q\n");
140 	/* Set MCR */
141 	outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
142 	     speakup_info.port_tts + UART_MCR);
143 	/* Turn on Interrupts */
144 	outb(UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI,
145 	     speakup_info.port_tts + UART_IER);
146 	inb(speakup_info.port_tts + UART_LSR);
147 	inb(speakup_info.port_tts + UART_RX);
148 	inb(speakup_info.port_tts + UART_IIR);
149 	inb(speakup_info.port_tts + UART_MSR);
150 	outb(1, speakup_info.port_tts + UART_FCR);	/* Turn FIFO On */
151 }
152 
153 static void spk_serial_send_xchar(char ch)
154 {
155 	int timeout = SPK_XMITR_TIMEOUT;
156 
157 	while (spk_serial_tx_busy()) {
158 		if (!--timeout)
159 			break;
160 		udelay(1);
161 	}
162 	outb(ch, speakup_info.port_tts);
163 }
164 
165 static void spk_serial_tiocmset(unsigned int set, unsigned int clear)
166 {
167 	int old = inb(speakup_info.port_tts + UART_MCR);
168 
169 	outb((old & ~clear) | set, speakup_info.port_tts + UART_MCR);
170 }
171 
172 int spk_serial_synth_probe(struct spk_synth *synth)
173 {
174 	const struct old_serial_port *ser;
175 	int failed = 0;
176 
177 	if ((synth->ser >= SPK_LO_TTY) && (synth->ser <= SPK_HI_TTY)) {
178 		ser = spk_serial_init(synth->ser);
179 		if (!ser) {
180 			failed = -1;
181 		} else {
182 			outb_p(0, ser->port);
183 			mdelay(1);
184 			outb_p('\r', ser->port);
185 		}
186 	} else {
187 		failed = -1;
188 		pr_warn("ttyS%i is an invalid port\n", synth->ser);
189 	}
190 	if (failed) {
191 		pr_info("%s: not found\n", synth->long_name);
192 		return -ENODEV;
193 	}
194 	pr_info("%s: ttyS%i, Driver Version %s\n",
195 		synth->long_name, synth->ser, synth->version);
196 	synth->alive = 1;
197 	return 0;
198 }
199 EXPORT_SYMBOL_GPL(spk_serial_synth_probe);
200 
201 void spk_stop_serial_interrupt(void)
202 {
203 	if (speakup_info.port_tts == 0)
204 		return;
205 
206 	if (!synth->read_buff_add)
207 		return;
208 
209 	/* Turn off interrupts */
210 	outb(0, speakup_info.port_tts + UART_IER);
211 	/* Free IRQ */
212 	free_irq(serstate->irq, (void *)synth_readbuf_handler);
213 }
214 EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);
215 
216 static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth)
217 {
218 	int tmout = SPK_XMITR_TIMEOUT;
219 
220 	if ((in_synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
221 		pr_warn("%s: too many timeouts, deactivating speakup\n",
222 			in_synth->long_name);
223 		in_synth->alive = 0;
224 		/* No synth any more, so nobody will restart TTYs, and we thus
225 		 * need to do it ourselves.  Now that there is no synth we can
226 		 * let application flood anyway
227 		 */
228 		speakup_start_ttys();
229 		timeouts = 0;
230 		return 0;
231 	}
232 	while (spk_serial_tx_busy()) {
233 		if (--tmout == 0) {
234 			pr_warn("%s: timed out (tx busy)\n",
235 				in_synth->long_name);
236 			timeouts++;
237 			return 0;
238 		}
239 		udelay(1);
240 	}
241 	tmout = SPK_CTS_TIMEOUT;
242 	while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
243 		/* CTS */
244 		if (--tmout == 0) {
245 			timeouts++;
246 			return 0;
247 		}
248 		udelay(1);
249 	}
250 	timeouts = 0;
251 	return 1;
252 }
253 
254 static unsigned char spk_serial_in(void)
255 {
256 	int tmout = SPK_SERIAL_TIMEOUT;
257 
258 	while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
259 		if (--tmout == 0) {
260 			pr_warn("time out while waiting for input.\n");
261 			return 0xff;
262 		}
263 		udelay(1);
264 	}
265 	return inb_p(speakup_info.port_tts + UART_RX);
266 }
267 
268 static unsigned char spk_serial_in_nowait(void)
269 {
270 	unsigned char lsr;
271 
272 	lsr = inb_p(speakup_info.port_tts + UART_LSR);
273 	if (!(lsr & UART_LSR_DR))
274 		return 0;
275 	return inb_p(speakup_info.port_tts + UART_RX);
276 }
277 
278 static void spk_serial_flush_buffer(void)
279 {
280 	/* TODO: flush the UART 16550 buffer */
281 }
282 
283 static int spk_serial_out(struct spk_synth *in_synth, const char ch)
284 {
285 	if (in_synth->alive && spk_serial_wait_for_xmitr(in_synth)) {
286 		outb_p(ch, speakup_info.port_tts);
287 		return 1;
288 	}
289 	return 0;
290 }
291 
292 const char *spk_serial_synth_immediate(struct spk_synth *synth,
293 				       const char *buff)
294 {
295 	u_char ch;
296 
297 	while ((ch = *buff)) {
298 		if (ch == '\n')
299 			ch = synth->procspeech;
300 		if (spk_serial_wait_for_xmitr(synth))
301 			outb(ch, speakup_info.port_tts);
302 		else
303 			return buff;
304 		buff++;
305 	}
306 	return NULL;
307 }
308 EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);
309 
310 void spk_serial_release(void)
311 {
312 	spk_stop_serial_interrupt();
313 	if (speakup_info.port_tts == 0)
314 		return;
315 	synth_release_region(speakup_info.port_tts, 8);
316 	speakup_info.port_tts = 0;
317 }
318 EXPORT_SYMBOL_GPL(spk_serial_release);
319