xref: /openbmc/u-boot/drivers/serial/serial.c (revision 3a97763a)
1 /*
2  * (C) Copyright 2004
3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <environment.h>
10 #include <serial.h>
11 #include <stdio_dev.h>
12 #include <post.h>
13 #include <linux/compiler.h>
14 #include <errno.h>
15 
16 DECLARE_GLOBAL_DATA_PTR;
17 
18 static struct serial_device *serial_devices;
19 static struct serial_device *serial_current;
20 /*
21  * Table with supported baudrates (defined in config_xyz.h)
22  */
23 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
24 
25 /**
26  * serial_null() - Void registration routine of a serial driver
27  *
28  * This routine implements a void registration routine of a serial
29  * driver. The registration routine of a particular driver is aliased
30  * to this empty function in case the driver is not compiled into
31  * U-Boot.
32  */
33 static void serial_null(void)
34 {
35 }
36 
37 /**
38  * on_baudrate() - Update the actual baudrate when the env var changes
39  *
40  * This will check for a valid baudrate and only apply it if valid.
41  */
42 static int on_baudrate(const char *name, const char *value, enum env_op op,
43 	int flags)
44 {
45 	int i;
46 	int baudrate;
47 
48 	switch (op) {
49 	case env_op_create:
50 	case env_op_overwrite:
51 		/*
52 		 * Switch to new baudrate if new baudrate is supported
53 		 */
54 		baudrate = simple_strtoul(value, NULL, 10);
55 
56 		/* Not actually changing */
57 		if (gd->baudrate == baudrate)
58 			return 0;
59 
60 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
61 			if (baudrate == baudrate_table[i])
62 				break;
63 		}
64 		if (i == ARRAY_SIZE(baudrate_table)) {
65 			if ((flags & H_FORCE) == 0)
66 				printf("## Baudrate %d bps not supported\n",
67 					baudrate);
68 			return 1;
69 		}
70 		if ((flags & H_INTERACTIVE) != 0) {
71 			printf("## Switch baudrate to %d"
72 				" bps and press ENTER ...\n", baudrate);
73 			udelay(50000);
74 		}
75 
76 		gd->baudrate = baudrate;
77 
78 		serial_setbrg();
79 
80 		udelay(50000);
81 
82 		if ((flags & H_INTERACTIVE) != 0)
83 			while (1) {
84 				if (getc() == '\r')
85 					break;
86 			}
87 
88 		return 0;
89 	case env_op_delete:
90 		printf("## Baudrate may not be deleted\n");
91 		return 1;
92 	default:
93 		return 0;
94 	}
95 }
96 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
97 
98 /**
99  * serial_initfunc() - Forward declare of driver registration routine
100  * @name:	Name of the real driver registration routine.
101  *
102  * This macro expands onto forward declaration of a driver registration
103  * routine, which is then used below in serial_initialize() function.
104  * The declaration is made weak and aliases to serial_null() so in case
105  * the driver is not compiled in, the function is still declared and can
106  * be used, but aliases to serial_null() and thus is optimized away.
107  */
108 #define serial_initfunc(name)					\
109 	void name(void)						\
110 		__attribute__((weak, alias("serial_null")));
111 
112 serial_initfunc(amirix_serial_initialize);
113 serial_initfunc(arc_serial_initialize);
114 serial_initfunc(arm_dcc_initialize);
115 serial_initfunc(asc_serial_initialize);
116 serial_initfunc(atmel_serial_initialize);
117 serial_initfunc(au1x00_serial_initialize);
118 serial_initfunc(bfin_jtag_initialize);
119 serial_initfunc(bfin_serial_initialize);
120 serial_initfunc(bmw_serial_initialize);
121 serial_initfunc(clps7111_serial_initialize);
122 serial_initfunc(cogent_serial_initialize);
123 serial_initfunc(cpci750_serial_initialize);
124 serial_initfunc(evb64260_serial_initialize);
125 serial_initfunc(imx_serial_initialize);
126 serial_initfunc(iop480_serial_initialize);
127 serial_initfunc(jz_serial_initialize);
128 serial_initfunc(leon2_serial_initialize);
129 serial_initfunc(leon3_serial_initialize);
130 serial_initfunc(lh7a40x_serial_initialize);
131 serial_initfunc(lpc32xx_serial_initialize);
132 serial_initfunc(marvell_serial_initialize);
133 serial_initfunc(max3100_serial_initialize);
134 serial_initfunc(mcf_serial_initialize);
135 serial_initfunc(ml2_serial_initialize);
136 serial_initfunc(mpc5xx_serial_initialize);
137 serial_initfunc(mpc8260_scc_serial_initialize);
138 serial_initfunc(mpc8260_smc_serial_initialize);
139 serial_initfunc(mpc85xx_serial_initialize);
140 serial_initfunc(mpc8xx_serial_initialize);
141 serial_initfunc(mxc_serial_initialize);
142 serial_initfunc(mxs_auart_initialize);
143 serial_initfunc(ns16550_serial_initialize);
144 serial_initfunc(oc_serial_initialize);
145 serial_initfunc(p3mx_serial_initialize);
146 serial_initfunc(pl01x_serial_initialize);
147 serial_initfunc(pxa_serial_initialize);
148 serial_initfunc(s3c24xx_serial_initialize);
149 serial_initfunc(s5p_serial_initialize);
150 serial_initfunc(sa1100_serial_initialize);
151 serial_initfunc(sandbox_serial_initialize);
152 serial_initfunc(sconsole_serial_initialize);
153 serial_initfunc(sh_serial_initialize);
154 serial_initfunc(stm32_serial_initialize);
155 serial_initfunc(uartlite_serial_initialize);
156 serial_initfunc(zynq_serial_initialize);
157 
158 /**
159  * serial_register() - Register serial driver with serial driver core
160  * @dev:	Pointer to the serial driver structure
161  *
162  * This function registers the serial driver supplied via @dev with
163  * serial driver core, thus making U-Boot aware of it and making it
164  * available for U-Boot to use. On platforms that still require manual
165  * relocation of constant variables, relocation of the supplied structure
166  * is performed.
167  */
168 void serial_register(struct serial_device *dev)
169 {
170 #ifdef CONFIG_NEEDS_MANUAL_RELOC
171 	if (dev->start)
172 		dev->start += gd->reloc_off;
173 	if (dev->stop)
174 		dev->stop += gd->reloc_off;
175 	if (dev->setbrg)
176 		dev->setbrg += gd->reloc_off;
177 	if (dev->getc)
178 		dev->getc += gd->reloc_off;
179 	if (dev->tstc)
180 		dev->tstc += gd->reloc_off;
181 	if (dev->putc)
182 		dev->putc += gd->reloc_off;
183 	if (dev->puts)
184 		dev->puts += gd->reloc_off;
185 #endif
186 
187 	dev->next = serial_devices;
188 	serial_devices = dev;
189 }
190 
191 /**
192  * serial_initialize() - Register all compiled-in serial port drivers
193  *
194  * This function registers all serial port drivers that are compiled
195  * into the U-Boot binary with the serial core, thus making them
196  * available to U-Boot to use. Lastly, this function assigns a default
197  * serial port to the serial core. That serial port is then used as a
198  * default output.
199  */
200 void serial_initialize(void)
201 {
202 	amirix_serial_initialize();
203 	arc_serial_initialize();
204 	arm_dcc_initialize();
205 	asc_serial_initialize();
206 	atmel_serial_initialize();
207 	au1x00_serial_initialize();
208 	bfin_jtag_initialize();
209 	bfin_serial_initialize();
210 	bmw_serial_initialize();
211 	clps7111_serial_initialize();
212 	cogent_serial_initialize();
213 	cpci750_serial_initialize();
214 	evb64260_serial_initialize();
215 	imx_serial_initialize();
216 	iop480_serial_initialize();
217 	jz_serial_initialize();
218 	leon2_serial_initialize();
219 	leon3_serial_initialize();
220 	lh7a40x_serial_initialize();
221 	lpc32xx_serial_initialize();
222 	marvell_serial_initialize();
223 	max3100_serial_initialize();
224 	mcf_serial_initialize();
225 	ml2_serial_initialize();
226 	mpc85xx_serial_initialize();
227 	mpc8xx_serial_initialize();
228 	mxc_serial_initialize();
229 	mxs_auart_initialize();
230 	ns16550_serial_initialize();
231 	oc_serial_initialize();
232 	p3mx_serial_initialize();
233 	pl01x_serial_initialize();
234 	pxa_serial_initialize();
235 	s3c24xx_serial_initialize();
236 	s5p_serial_initialize();
237 	sa1100_serial_initialize();
238 	sandbox_serial_initialize();
239 	sconsole_serial_initialize();
240 	sh_serial_initialize();
241 	stm32_serial_initialize();
242 	uartlite_serial_initialize();
243 	zynq_serial_initialize();
244 
245 	serial_assign(default_serial_console()->name);
246 }
247 
248 static int serial_stub_start(struct stdio_dev *sdev)
249 {
250 	struct serial_device *dev = sdev->priv;
251 
252 	return dev->start();
253 }
254 
255 static int serial_stub_stop(struct stdio_dev *sdev)
256 {
257 	struct serial_device *dev = sdev->priv;
258 
259 	return dev->stop();
260 }
261 
262 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
263 {
264 	struct serial_device *dev = sdev->priv;
265 
266 	dev->putc(ch);
267 }
268 
269 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
270 {
271 	struct serial_device *dev = sdev->priv;
272 
273 	dev->puts(str);
274 }
275 
276 int serial_stub_getc(struct stdio_dev *sdev)
277 {
278 	struct serial_device *dev = sdev->priv;
279 
280 	return dev->getc();
281 }
282 
283 int serial_stub_tstc(struct stdio_dev *sdev)
284 {
285 	struct serial_device *dev = sdev->priv;
286 
287 	return dev->tstc();
288 }
289 
290 /**
291  * serial_stdio_init() - Register serial ports with STDIO core
292  *
293  * This function generates a proxy driver for each serial port driver.
294  * These proxy drivers then register with the STDIO core, making the
295  * serial drivers available as STDIO devices.
296  */
297 void serial_stdio_init(void)
298 {
299 	struct stdio_dev dev;
300 	struct serial_device *s = serial_devices;
301 
302 	while (s) {
303 		memset(&dev, 0, sizeof(dev));
304 
305 		strcpy(dev.name, s->name);
306 		dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
307 
308 		dev.start = serial_stub_start;
309 		dev.stop = serial_stub_stop;
310 		dev.putc = serial_stub_putc;
311 		dev.puts = serial_stub_puts;
312 		dev.getc = serial_stub_getc;
313 		dev.tstc = serial_stub_tstc;
314 		dev.priv = s;
315 
316 		stdio_register(&dev);
317 
318 		s = s->next;
319 	}
320 }
321 
322 /**
323  * serial_assign() - Select the serial output device by name
324  * @name:	Name of the serial driver to be used as default output
325  *
326  * This function configures the serial output multiplexing by
327  * selecting which serial device will be used as default. In case
328  * the STDIO "serial" device is selected as stdin/stdout/stderr,
329  * the serial device previously configured by this function will be
330  * used for the particular operation.
331  *
332  * Returns 0 on success, negative on error.
333  */
334 int serial_assign(const char *name)
335 {
336 	struct serial_device *s;
337 
338 	for (s = serial_devices; s; s = s->next) {
339 		if (strcmp(s->name, name))
340 			continue;
341 		serial_current = s;
342 		return 0;
343 	}
344 
345 	return -EINVAL;
346 }
347 
348 /**
349  * serial_reinit_all() - Reinitialize all compiled-in serial ports
350  *
351  * This function reinitializes all serial ports that are compiled
352  * into U-Boot by calling their serial_start() functions.
353  */
354 void serial_reinit_all(void)
355 {
356 	struct serial_device *s;
357 
358 	for (s = serial_devices; s; s = s->next)
359 		s->start();
360 }
361 
362 /**
363  * get_current() - Return pointer to currently selected serial port
364  *
365  * This function returns a pointer to currently selected serial port.
366  * The currently selected serial port is altered by serial_assign()
367  * function.
368  *
369  * In case this function is called before relocation or before any serial
370  * port is configured, this function calls default_serial_console() to
371  * determine the serial port. Otherwise, the configured serial port is
372  * returned.
373  *
374  * Returns pointer to the currently selected serial port on success,
375  * NULL on error.
376  */
377 static struct serial_device *get_current(void)
378 {
379 	struct serial_device *dev;
380 
381 	if (!(gd->flags & GD_FLG_RELOC))
382 		dev = default_serial_console();
383 	else if (!serial_current)
384 		dev = default_serial_console();
385 	else
386 		dev = serial_current;
387 
388 	/* We must have a console device */
389 	if (!dev) {
390 #ifdef CONFIG_SPL_BUILD
391 		puts("Cannot find console\n");
392 		hang();
393 #else
394 		panic("Cannot find console\n");
395 #endif
396 	}
397 
398 	return dev;
399 }
400 
401 /**
402  * serial_init() - Initialize currently selected serial port
403  *
404  * This function initializes the currently selected serial port. This
405  * usually involves setting up the registers of that particular port,
406  * enabling clock and such. This function uses the get_current() call
407  * to determine which port is selected.
408  *
409  * Returns 0 on success, negative on error.
410  */
411 int serial_init(void)
412 {
413 	gd->flags |= GD_FLG_SERIAL_READY;
414 	return get_current()->start();
415 }
416 
417 /**
418  * serial_setbrg() - Configure baud-rate of currently selected serial port
419  *
420  * This function configures the baud-rate of the currently selected
421  * serial port. The baud-rate is retrieved from global data within
422  * the serial port driver. This function uses the get_current() call
423  * to determine which port is selected.
424  *
425  * Returns 0 on success, negative on error.
426  */
427 void serial_setbrg(void)
428 {
429 	get_current()->setbrg();
430 }
431 
432 /**
433  * serial_getc() - Read character from currently selected serial port
434  *
435  * This function retrieves a character from currently selected serial
436  * port. In case there is no character waiting on the serial port,
437  * this function will block and wait for the character to appear. This
438  * function uses the get_current() call to determine which port is
439  * selected.
440  *
441  * Returns the character on success, negative on error.
442  */
443 int serial_getc(void)
444 {
445 	return get_current()->getc();
446 }
447 
448 /**
449  * serial_tstc() - Test if data is available on currently selected serial port
450  *
451  * This function tests if one or more characters are available on
452  * currently selected serial port. This function never blocks. This
453  * function uses the get_current() call to determine which port is
454  * selected.
455  *
456  * Returns positive if character is available, zero otherwise.
457  */
458 int serial_tstc(void)
459 {
460 	return get_current()->tstc();
461 }
462 
463 /**
464  * serial_putc() - Output character via currently selected serial port
465  * @c:	Single character to be output from the serial port.
466  *
467  * This function outputs a character via currently selected serial
468  * port. This character is passed to the serial port driver responsible
469  * for controlling the hardware. The hardware may still be in process
470  * of transmitting another character, therefore this function may block
471  * for a short amount of time. This function uses the get_current()
472  * call to determine which port is selected.
473  */
474 void serial_putc(const char c)
475 {
476 	get_current()->putc(c);
477 }
478 
479 /**
480  * serial_puts() - Output string via currently selected serial port
481  * @s:	Zero-terminated string to be output from the serial port.
482  *
483  * This function outputs a zero-terminated string via currently
484  * selected serial port. This function behaves as an accelerator
485  * in case the hardware can queue multiple characters for transfer.
486  * The whole string that is to be output is available to the function
487  * implementing the hardware manipulation. Transmitting the whole
488  * string may take some time, thus this function may block for some
489  * amount of time. This function uses the get_current() call to
490  * determine which port is selected.
491  */
492 void serial_puts(const char *s)
493 {
494 	get_current()->puts(s);
495 }
496 
497 /**
498  * default_serial_puts() - Output string by calling serial_putc() in loop
499  * @s:	Zero-terminated string to be output from the serial port.
500  *
501  * This function outputs a zero-terminated string by calling serial_putc()
502  * in a loop. Most drivers do not support queueing more than one byte for
503  * transfer, thus this function precisely implements their serial_puts().
504  *
505  * To optimize the number of get_current() calls, this function only
506  * calls get_current() once and then directly accesses the putc() call
507  * of the &struct serial_device .
508  */
509 void default_serial_puts(const char *s)
510 {
511 	struct serial_device *dev = get_current();
512 	while (*s)
513 		dev->putc(*s++);
514 }
515 
516 #if CONFIG_POST & CONFIG_SYS_POST_UART
517 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
518 
519 /**
520  * uart_post_test() - Test the currently selected serial port using POST
521  * @flags:	POST framework flags
522  *
523  * Do a loopback test of the currently selected serial port. This
524  * function is only useful in the context of the POST testing framwork.
525  * The serial port is first configured into loopback mode and then
526  * characters are sent through it.
527  *
528  * Returns 0 on success, value otherwise.
529  */
530 /* Mark weak until post/cpu/.../uart.c migrate over */
531 __weak
532 int uart_post_test(int flags)
533 {
534 	unsigned char c;
535 	int ret, saved_baud, b;
536 	struct serial_device *saved_dev, *s;
537 
538 	/* Save current serial state */
539 	ret = 0;
540 	saved_dev = serial_current;
541 	saved_baud = gd->baudrate;
542 
543 	for (s = serial_devices; s; s = s->next) {
544 		/* If this driver doesn't support loop back, skip it */
545 		if (!s->loop)
546 			continue;
547 
548 		/* Test the next device */
549 		serial_current = s;
550 
551 		ret = serial_init();
552 		if (ret)
553 			goto done;
554 
555 		/* Consume anything that happens to be queued */
556 		while (serial_tstc())
557 			serial_getc();
558 
559 		/* Enable loop back */
560 		s->loop(1);
561 
562 		/* Test every available baud rate */
563 		for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
564 			gd->baudrate = bauds[b];
565 			serial_setbrg();
566 
567 			/*
568 			 * Stick to printable chars to avoid issues:
569 			 *  - terminal corruption
570 			 *  - serial program reacting to sequences and sending
571 			 *    back random extra data
572 			 *  - most serial drivers add in extra chars (like \r\n)
573 			 */
574 			for (c = 0x20; c < 0x7f; ++c) {
575 				/* Send it out */
576 				serial_putc(c);
577 
578 				/* Make sure it's the same one */
579 				ret = (c != serial_getc());
580 				if (ret) {
581 					s->loop(0);
582 					goto done;
583 				}
584 
585 				/* Clean up the output in case it was sent */
586 				serial_putc('\b');
587 				ret = ('\b' != serial_getc());
588 				if (ret) {
589 					s->loop(0);
590 					goto done;
591 				}
592 			}
593 		}
594 
595 		/* Disable loop back */
596 		s->loop(0);
597 
598 		/* XXX: There is no serial_stop() !? */
599 		if (s->stop)
600 			s->stop();
601 	}
602 
603  done:
604 	/* Restore previous serial state */
605 	serial_current = saved_dev;
606 	gd->baudrate = saved_baud;
607 	serial_reinit_all();
608 	serial_setbrg();
609 
610 	return ret;
611 }
612 #endif
613