xref: /openbmc/u-boot/drivers/serial/serial.c (revision cd23aac4)
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(mpc8xx_serial_initialize);
113 serial_initfunc(ns16550_serial_initialize);
114 serial_initfunc(pxa_serial_initialize);
115 serial_initfunc(s3c24xx_serial_initialize);
116 serial_initfunc(s5p_serial_initialize);
117 serial_initfunc(zynq_serial_initialize);
118 serial_initfunc(bfin_serial_initialize);
119 serial_initfunc(bfin_jtag_initialize);
120 serial_initfunc(mpc512x_serial_initialize);
121 serial_initfunc(uartlite_serial_initialize);
122 serial_initfunc(au1x00_serial_initialize);
123 serial_initfunc(asc_serial_initialize);
124 serial_initfunc(jz_serial_initialize);
125 serial_initfunc(mpc5xx_serial_initialize);
126 serial_initfunc(mpc8260_scc_serial_initialize);
127 serial_initfunc(mpc8260_smc_serial_initialize);
128 serial_initfunc(mpc85xx_serial_initialize);
129 serial_initfunc(iop480_serial_initialize);
130 serial_initfunc(leon2_serial_initialize);
131 serial_initfunc(leon3_serial_initialize);
132 serial_initfunc(marvell_serial_initialize);
133 serial_initfunc(amirix_serial_initialize);
134 serial_initfunc(bmw_serial_initialize);
135 serial_initfunc(cogent_serial_initialize);
136 serial_initfunc(cpci750_serial_initialize);
137 serial_initfunc(evb64260_serial_initialize);
138 serial_initfunc(ml2_serial_initialize);
139 serial_initfunc(sconsole_serial_initialize);
140 serial_initfunc(p3mx_serial_initialize);
141 serial_initfunc(altera_jtag_serial_initialize);
142 serial_initfunc(altera_serial_initialize);
143 serial_initfunc(atmel_serial_initialize);
144 serial_initfunc(lpc32xx_serial_initialize);
145 serial_initfunc(mcf_serial_initialize);
146 serial_initfunc(oc_serial_initialize);
147 serial_initfunc(sandbox_serial_initialize);
148 serial_initfunc(clps7111_serial_initialize);
149 serial_initfunc(imx_serial_initialize);
150 serial_initfunc(ks8695_serial_initialize);
151 serial_initfunc(lh7a40x_serial_initialize);
152 serial_initfunc(max3100_serial_initialize);
153 serial_initfunc(mxc_serial_initialize);
154 serial_initfunc(pl01x_serial_initialize);
155 serial_initfunc(sa1100_serial_initialize);
156 serial_initfunc(sh_serial_initialize);
157 serial_initfunc(arm_dcc_initialize);
158 serial_initfunc(mxs_auart_initialize);
159 serial_initfunc(arc_serial_initialize);
160 
161 /**
162  * serial_register() - Register serial driver with serial driver core
163  * @dev:	Pointer to the serial driver structure
164  *
165  * This function registers the serial driver supplied via @dev with
166  * serial driver core, thus making U-Boot aware of it and making it
167  * available for U-Boot to use. On platforms that still require manual
168  * relocation of constant variables, relocation of the supplied structure
169  * is performed.
170  */
171 void serial_register(struct serial_device *dev)
172 {
173 #ifdef CONFIG_NEEDS_MANUAL_RELOC
174 	if (dev->start)
175 		dev->start += gd->reloc_off;
176 	if (dev->stop)
177 		dev->stop += gd->reloc_off;
178 	if (dev->setbrg)
179 		dev->setbrg += gd->reloc_off;
180 	if (dev->getc)
181 		dev->getc += gd->reloc_off;
182 	if (dev->tstc)
183 		dev->tstc += gd->reloc_off;
184 	if (dev->putc)
185 		dev->putc += gd->reloc_off;
186 	if (dev->puts)
187 		dev->puts += gd->reloc_off;
188 #endif
189 
190 	dev->next = serial_devices;
191 	serial_devices = dev;
192 }
193 
194 /**
195  * serial_initialize() - Register all compiled-in serial port drivers
196  *
197  * This function registers all serial port drivers that are compiled
198  * into the U-Boot binary with the serial core, thus making them
199  * available to U-Boot to use. Lastly, this function assigns a default
200  * serial port to the serial core. That serial port is then used as a
201  * default output.
202  */
203 void serial_initialize(void)
204 {
205 	mpc8xx_serial_initialize();
206 	ns16550_serial_initialize();
207 	pxa_serial_initialize();
208 	s3c24xx_serial_initialize();
209 	s5p_serial_initialize();
210 	mpc512x_serial_initialize();
211 	bfin_serial_initialize();
212 	bfin_jtag_initialize();
213 	uartlite_serial_initialize();
214 	zynq_serial_initialize();
215 	au1x00_serial_initialize();
216 	asc_serial_initialize();
217 	jz_serial_initialize();
218 	mpc5xx_serial_initialize();
219 	mpc8260_scc_serial_initialize();
220 	mpc8260_smc_serial_initialize();
221 	mpc85xx_serial_initialize();
222 	iop480_serial_initialize();
223 	leon2_serial_initialize();
224 	leon3_serial_initialize();
225 	marvell_serial_initialize();
226 	amirix_serial_initialize();
227 	bmw_serial_initialize();
228 	cogent_serial_initialize();
229 	cpci750_serial_initialize();
230 	evb64260_serial_initialize();
231 	ml2_serial_initialize();
232 	sconsole_serial_initialize();
233 	p3mx_serial_initialize();
234 	altera_jtag_serial_initialize();
235 	altera_serial_initialize();
236 	atmel_serial_initialize();
237 	lpc32xx_serial_initialize();
238 	mcf_serial_initialize();
239 	oc_serial_initialize();
240 	sandbox_serial_initialize();
241 	clps7111_serial_initialize();
242 	imx_serial_initialize();
243 	ks8695_serial_initialize();
244 	lh7a40x_serial_initialize();
245 	max3100_serial_initialize();
246 	mxc_serial_initialize();
247 	pl01x_serial_initialize();
248 	sa1100_serial_initialize();
249 	sh_serial_initialize();
250 	arm_dcc_initialize();
251 	mxs_auart_initialize();
252 	arc_serial_initialize();
253 
254 	serial_assign(default_serial_console()->name);
255 }
256 
257 /**
258  * serial_stdio_init() - Register serial ports with STDIO core
259  *
260  * This function generates a proxy driver for each serial port driver.
261  * These proxy drivers then register with the STDIO core, making the
262  * serial drivers available as STDIO devices.
263  */
264 void serial_stdio_init(void)
265 {
266 	struct stdio_dev dev;
267 	struct serial_device *s = serial_devices;
268 
269 	while (s) {
270 		memset(&dev, 0, sizeof(dev));
271 
272 		strcpy(dev.name, s->name);
273 		dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
274 
275 		dev.start = s->start;
276 		dev.stop = s->stop;
277 		dev.putc = s->putc;
278 		dev.puts = s->puts;
279 		dev.getc = s->getc;
280 		dev.tstc = s->tstc;
281 
282 		stdio_register(&dev);
283 
284 		s = s->next;
285 	}
286 }
287 
288 /**
289  * serial_assign() - Select the serial output device by name
290  * @name:	Name of the serial driver to be used as default output
291  *
292  * This function configures the serial output multiplexing by
293  * selecting which serial device will be used as default. In case
294  * the STDIO "serial" device is selected as stdin/stdout/stderr,
295  * the serial device previously configured by this function will be
296  * used for the particular operation.
297  *
298  * Returns 0 on success, negative on error.
299  */
300 int serial_assign(const char *name)
301 {
302 	struct serial_device *s;
303 
304 	for (s = serial_devices; s; s = s->next) {
305 		if (strcmp(s->name, name))
306 			continue;
307 		serial_current = s;
308 		return 0;
309 	}
310 
311 	return -EINVAL;
312 }
313 
314 /**
315  * serial_reinit_all() - Reinitialize all compiled-in serial ports
316  *
317  * This function reinitializes all serial ports that are compiled
318  * into U-Boot by calling their serial_start() functions.
319  */
320 void serial_reinit_all(void)
321 {
322 	struct serial_device *s;
323 
324 	for (s = serial_devices; s; s = s->next)
325 		s->start();
326 }
327 
328 /**
329  * get_current() - Return pointer to currently selected serial port
330  *
331  * This function returns a pointer to currently selected serial port.
332  * The currently selected serial port is altered by serial_assign()
333  * function.
334  *
335  * In case this function is called before relocation or before any serial
336  * port is configured, this function calls default_serial_console() to
337  * determine the serial port. Otherwise, the configured serial port is
338  * returned.
339  *
340  * Returns pointer to the currently selected serial port on success,
341  * NULL on error.
342  */
343 static struct serial_device *get_current(void)
344 {
345 	struct serial_device *dev;
346 
347 	if (!(gd->flags & GD_FLG_RELOC))
348 		dev = default_serial_console();
349 	else if (!serial_current)
350 		dev = default_serial_console();
351 	else
352 		dev = serial_current;
353 
354 	/* We must have a console device */
355 	if (!dev) {
356 #ifdef CONFIG_SPL_BUILD
357 		puts("Cannot find console\n");
358 		hang();
359 #else
360 		panic("Cannot find console\n");
361 #endif
362 	}
363 
364 	return dev;
365 }
366 
367 /**
368  * serial_init() - Initialize currently selected serial port
369  *
370  * This function initializes the currently selected serial port. This
371  * usually involves setting up the registers of that particular port,
372  * enabling clock and such. This function uses the get_current() call
373  * to determine which port is selected.
374  *
375  * Returns 0 on success, negative on error.
376  */
377 int serial_init(void)
378 {
379 	return get_current()->start();
380 }
381 
382 /**
383  * serial_setbrg() - Configure baud-rate of currently selected serial port
384  *
385  * This function configures the baud-rate of the currently selected
386  * serial port. The baud-rate is retrieved from global data within
387  * the serial port driver. This function uses the get_current() call
388  * to determine which port is selected.
389  *
390  * Returns 0 on success, negative on error.
391  */
392 void serial_setbrg(void)
393 {
394 	get_current()->setbrg();
395 }
396 
397 /**
398  * serial_getc() - Read character from currently selected serial port
399  *
400  * This function retrieves a character from currently selected serial
401  * port. In case there is no character waiting on the serial port,
402  * this function will block and wait for the character to appear. This
403  * function uses the get_current() call to determine which port is
404  * selected.
405  *
406  * Returns the character on success, negative on error.
407  */
408 int serial_getc(void)
409 {
410 	return get_current()->getc();
411 }
412 
413 /**
414  * serial_tstc() - Test if data is available on currently selected serial port
415  *
416  * This function tests if one or more characters are available on
417  * currently selected serial port. This function never blocks. This
418  * function uses the get_current() call to determine which port is
419  * selected.
420  *
421  * Returns positive if character is available, zero otherwise.
422  */
423 int serial_tstc(void)
424 {
425 	return get_current()->tstc();
426 }
427 
428 /**
429  * serial_putc() - Output character via currently selected serial port
430  * @c:	Single character to be output from the serial port.
431  *
432  * This function outputs a character via currently selected serial
433  * port. This character is passed to the serial port driver responsible
434  * for controlling the hardware. The hardware may still be in process
435  * of transmitting another character, therefore this function may block
436  * for a short amount of time. This function uses the get_current()
437  * call to determine which port is selected.
438  */
439 void serial_putc(const char c)
440 {
441 	get_current()->putc(c);
442 }
443 
444 /**
445  * serial_puts() - Output string via currently selected serial port
446  * @s:	Zero-terminated string to be output from the serial port.
447  *
448  * This function outputs a zero-terminated string via currently
449  * selected serial port. This function behaves as an accelerator
450  * in case the hardware can queue multiple characters for transfer.
451  * The whole string that is to be output is available to the function
452  * implementing the hardware manipulation. Transmitting the whole
453  * string may take some time, thus this function may block for some
454  * amount of time. This function uses the get_current() call to
455  * determine which port is selected.
456  */
457 void serial_puts(const char *s)
458 {
459 	get_current()->puts(s);
460 }
461 
462 /**
463  * default_serial_puts() - Output string by calling serial_putc() in loop
464  * @s:	Zero-terminated string to be output from the serial port.
465  *
466  * This function outputs a zero-terminated string by calling serial_putc()
467  * in a loop. Most drivers do not support queueing more than one byte for
468  * transfer, thus this function precisely implements their serial_puts().
469  *
470  * To optimize the number of get_current() calls, this function only
471  * calls get_current() once and then directly accesses the putc() call
472  * of the &struct serial_device .
473  */
474 void default_serial_puts(const char *s)
475 {
476 	struct serial_device *dev = get_current();
477 	while (*s)
478 		dev->putc(*s++);
479 }
480 
481 #if CONFIG_POST & CONFIG_SYS_POST_UART
482 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
483 
484 /**
485  * uart_post_test() - Test the currently selected serial port using POST
486  * @flags:	POST framework flags
487  *
488  * Do a loopback test of the currently selected serial port. This
489  * function is only useful in the context of the POST testing framwork.
490  * The serial port is firstly configured into loopback mode and then
491  * characters are sent through it.
492  *
493  * Returns 0 on success, value otherwise.
494  */
495 /* Mark weak until post/cpu/.../uart.c migrate over */
496 __weak
497 int uart_post_test(int flags)
498 {
499 	unsigned char c;
500 	int ret, saved_baud, b;
501 	struct serial_device *saved_dev, *s;
502 
503 	/* Save current serial state */
504 	ret = 0;
505 	saved_dev = serial_current;
506 	saved_baud = gd->baudrate;
507 
508 	for (s = serial_devices; s; s = s->next) {
509 		/* If this driver doesn't support loop back, skip it */
510 		if (!s->loop)
511 			continue;
512 
513 		/* Test the next device */
514 		serial_current = s;
515 
516 		ret = serial_init();
517 		if (ret)
518 			goto done;
519 
520 		/* Consume anything that happens to be queued */
521 		while (serial_tstc())
522 			serial_getc();
523 
524 		/* Enable loop back */
525 		s->loop(1);
526 
527 		/* Test every available baud rate */
528 		for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
529 			gd->baudrate = bauds[b];
530 			serial_setbrg();
531 
532 			/*
533 			 * Stick to printable chars to avoid issues:
534 			 *  - terminal corruption
535 			 *  - serial program reacting to sequences and sending
536 			 *    back random extra data
537 			 *  - most serial drivers add in extra chars (like \r\n)
538 			 */
539 			for (c = 0x20; c < 0x7f; ++c) {
540 				/* Send it out */
541 				serial_putc(c);
542 
543 				/* Make sure it's the same one */
544 				ret = (c != serial_getc());
545 				if (ret) {
546 					s->loop(0);
547 					goto done;
548 				}
549 
550 				/* Clean up the output in case it was sent */
551 				serial_putc('\b');
552 				ret = ('\b' != serial_getc());
553 				if (ret) {
554 					s->loop(0);
555 					goto done;
556 				}
557 			}
558 		}
559 
560 		/* Disable loop back */
561 		s->loop(0);
562 
563 		/* XXX: There is no serial_stop() !? */
564 		if (s->stop)
565 			s->stop();
566 	}
567 
568  done:
569 	/* Restore previous serial state */
570 	serial_current = saved_dev;
571 	gd->baudrate = saved_baud;
572 	serial_reinit_all();
573 	serial_setbrg();
574 
575 	return ret;
576 }
577 #endif
578