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 
36 struct spk_io_ops spk_serial_io_ops = {
37 	.synth_out = spk_serial_out,
38 	.send_xchar = spk_serial_send_xchar,
39 	.tiocmset = spk_serial_tiocmset,
40 	.synth_in = spk_serial_in,
41 	.synth_in_nowait = spk_serial_in_nowait,
42 	.flush_buffer = spk_serial_flush_buffer,
43 };
44 EXPORT_SYMBOL_GPL(spk_serial_io_ops);
45 
46 const struct old_serial_port *spk_serial_init(int index)
47 {
48 	int baud = 9600, quot = 0;
49 	unsigned int cval = 0;
50 	int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
51 	const struct old_serial_port *ser;
52 	int err;
53 
54 	if (index >= ARRAY_SIZE(rs_table)) {
55 		pr_info("no port info for ttyS%d\n", index);
56 		return NULL;
57 	}
58 	ser = rs_table + index;
59 
60 	/*	Divisor, bytesize and parity */
61 	quot = ser->baud_base / baud;
62 	cval = cflag & (CSIZE | CSTOPB);
63 #if defined(__powerpc__) || defined(__alpha__)
64 	cval >>= 8;
65 #else /* !__powerpc__ && !__alpha__ */
66 	cval >>= 4;
67 #endif /* !__powerpc__ && !__alpha__ */
68 	if (cflag & PARENB)
69 		cval |= UART_LCR_PARITY;
70 	if (!(cflag & PARODD))
71 		cval |= UART_LCR_EPAR;
72 	if (synth_request_region(ser->port, 8)) {
73 		/* try to take it back. */
74 		pr_info("Ports not available, trying to steal them\n");
75 		__release_region(&ioport_resource, ser->port, 8);
76 		err = synth_request_region(ser->port, 8);
77 		if (err) {
78 			pr_warn("Unable to allocate port at %x, errno %i",
79 				ser->port, err);
80 			return NULL;
81 		}
82 	}
83 
84 	/*	Disable UART interrupts, set DTR and RTS high
85 	 *	and set speed.
86 	 */
87 	outb(cval | UART_LCR_DLAB, ser->port + UART_LCR);	/* set DLAB */
88 	outb(quot & 0xff, ser->port + UART_DLL);	/* LS of divisor */
89 	outb(quot >> 8, ser->port + UART_DLM);		/* MS of divisor */
90 	outb(cval, ser->port + UART_LCR);		/* reset DLAB */
91 
92 	/* Turn off Interrupts */
93 	outb(0, ser->port + UART_IER);
94 	outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);
95 
96 	/* If we read 0xff from the LSR, there is no UART here. */
97 	if (inb(ser->port + UART_LSR) == 0xff) {
98 		synth_release_region(ser->port, 8);
99 		serstate = NULL;
100 		return NULL;
101 	}
102 
103 	mdelay(1);
104 	speakup_info.port_tts = ser->port;
105 	serstate = ser;
106 
107 	start_serial_interrupt(ser->irq);
108 
109 	return ser;
110 }
111 
112 static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
113 {
114 	unsigned long flags;
115 	int c;
116 
117 	spin_lock_irqsave(&speakup_info.spinlock, flags);
118 	while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {
119 		c = inb_p(speakup_info.port_tts + UART_RX);
120 		synth->read_buff_add((u_char)c);
121 	}
122 	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
123 	return IRQ_HANDLED;
124 }
125 
126 static void start_serial_interrupt(int irq)
127 {
128 	int rv;
129 
130 	if (!synth->read_buff_add)
131 		return;
132 
133 	rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
134 			 "serial", (void *)synth_readbuf_handler);
135 
136 	if (rv)
137 		pr_err("Unable to request Speakup serial I R Q\n");
138 	/* Set MCR */
139 	outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
140 	     speakup_info.port_tts + UART_MCR);
141 	/* Turn on Interrupts */
142 	outb(UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI,
143 	     speakup_info.port_tts + UART_IER);
144 	inb(speakup_info.port_tts + UART_LSR);
145 	inb(speakup_info.port_tts + UART_RX);
146 	inb(speakup_info.port_tts + UART_IIR);
147 	inb(speakup_info.port_tts + UART_MSR);
148 	outb(1, speakup_info.port_tts + UART_FCR);	/* Turn FIFO On */
149 }
150 
151 static void spk_serial_send_xchar(char ch)
152 {
153 	int timeout = SPK_XMITR_TIMEOUT;
154 
155 	while (spk_serial_tx_busy()) {
156 		if (!--timeout)
157 			break;
158 		udelay(1);
159 	}
160 	outb(ch, speakup_info.port_tts);
161 }
162 
163 static void spk_serial_tiocmset(unsigned int set, unsigned int clear)
164 {
165 	int old = inb(speakup_info.port_tts + UART_MCR);
166 
167 	outb((old & ~clear) | set, speakup_info.port_tts + UART_MCR);
168 }
169 
170 int spk_serial_synth_probe(struct spk_synth *synth)
171 {
172 	const struct old_serial_port *ser;
173 	int failed = 0;
174 
175 	if ((synth->ser >= SPK_LO_TTY) && (synth->ser <= SPK_HI_TTY)) {
176 		ser = spk_serial_init(synth->ser);
177 		if (!ser) {
178 			failed = -1;
179 		} else {
180 			outb_p(0, ser->port);
181 			mdelay(1);
182 			outb_p('\r', ser->port);
183 		}
184 	} else {
185 		failed = -1;
186 		pr_warn("ttyS%i is an invalid port\n", synth->ser);
187 	}
188 	if (failed) {
189 		pr_info("%s: not found\n", synth->long_name);
190 		return -ENODEV;
191 	}
192 	pr_info("%s: ttyS%i, Driver Version %s\n",
193 		synth->long_name, synth->ser, synth->version);
194 	synth->alive = 1;
195 	return 0;
196 }
197 EXPORT_SYMBOL_GPL(spk_serial_synth_probe);
198 
199 void spk_stop_serial_interrupt(void)
200 {
201 	if (speakup_info.port_tts == 0)
202 		return;
203 
204 	if (!synth->read_buff_add)
205 		return;
206 
207 	/* Turn off interrupts */
208 	outb(0, speakup_info.port_tts + UART_IER);
209 	/* Free IRQ */
210 	free_irq(serstate->irq, (void *)synth_readbuf_handler);
211 }
212 EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);
213 
214 int spk_wait_for_xmitr(struct spk_synth *in_synth)
215 {
216 	int tmout = SPK_XMITR_TIMEOUT;
217 
218 	if ((in_synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
219 		pr_warn("%s: too many timeouts, deactivating speakup\n",
220 			in_synth->long_name);
221 		in_synth->alive = 0;
222 		/* No synth any more, so nobody will restart TTYs, and we thus
223 		 * need to do it ourselves.  Now that there is no synth we can
224 		 * let application flood anyway
225 		 */
226 		speakup_start_ttys();
227 		timeouts = 0;
228 		return 0;
229 	}
230 	while (spk_serial_tx_busy()) {
231 		if (--tmout == 0) {
232 			pr_warn("%s: timed out (tx busy)\n",
233 				in_synth->long_name);
234 			timeouts++;
235 			return 0;
236 		}
237 		udelay(1);
238 	}
239 	tmout = SPK_CTS_TIMEOUT;
240 	while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
241 		/* CTS */
242 		if (--tmout == 0) {
243 			timeouts++;
244 			return 0;
245 		}
246 		udelay(1);
247 	}
248 	timeouts = 0;
249 	return 1;
250 }
251 
252 static unsigned char spk_serial_in(void)
253 {
254 	int tmout = SPK_SERIAL_TIMEOUT;
255 
256 	while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
257 		if (--tmout == 0) {
258 			pr_warn("time out while waiting for input.\n");
259 			return 0xff;
260 		}
261 		udelay(1);
262 	}
263 	return inb_p(speakup_info.port_tts + UART_RX);
264 }
265 
266 static unsigned char spk_serial_in_nowait(void)
267 {
268 	unsigned char lsr;
269 
270 	lsr = inb_p(speakup_info.port_tts + UART_LSR);
271 	if (!(lsr & UART_LSR_DR))
272 		return 0;
273 	return inb_p(speakup_info.port_tts + UART_RX);
274 }
275 
276 static void spk_serial_flush_buffer(void)
277 {
278 	/* TODO: flush the UART 16550 buffer */
279 }
280 
281 static int spk_serial_out(struct spk_synth *in_synth, const char ch)
282 {
283 	if (in_synth->alive && spk_wait_for_xmitr(in_synth)) {
284 		outb_p(ch, speakup_info.port_tts);
285 		return 1;
286 	}
287 	return 0;
288 }
289 
290 const char *spk_serial_synth_immediate(struct spk_synth *synth,
291 				       const char *buff)
292 {
293 	u_char ch;
294 
295 	while ((ch = *buff)) {
296 		if (ch == '\n')
297 			ch = synth->procspeech;
298 		if (spk_wait_for_xmitr(synth))
299 			outb(ch, speakup_info.port_tts);
300 		else
301 			return buff;
302 		buff++;
303 	}
304 	return NULL;
305 }
306 EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);
307 
308 void spk_serial_release(void)
309 {
310 	spk_stop_serial_interrupt();
311 	if (speakup_info.port_tts == 0)
312 		return;
313 	synth_release_region(speakup_info.port_tts, 8);
314 	speakup_info.port_tts = 0;
315 }
316 EXPORT_SYMBOL_GPL(spk_serial_release);
317