xref: /openbmc/u-boot/drivers/serial/serial.c (revision 425faf74)
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 #if defined(CONFIG_PPC) || defined(CONFIG_MCF52x2)
78 		gd->bd->bi_baudrate = baudrate;
79 #endif
80 
81 		serial_setbrg();
82 
83 		udelay(50000);
84 
85 		if ((flags & H_INTERACTIVE) != 0)
86 			while (1) {
87 				if (getc() == '\r')
88 					break;
89 			}
90 
91 		return 0;
92 	case env_op_delete:
93 		printf("## Baudrate may not be deleted\n");
94 		return 1;
95 	default:
96 		return 0;
97 	}
98 }
99 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
100 
101 /**
102  * serial_initfunc() - Forward declare of driver registration routine
103  * @name:	Name of the real driver registration routine.
104  *
105  * This macro expands onto forward declaration of a driver registration
106  * routine, which is then used below in serial_initialize() function.
107  * The declaration is made weak and aliases to serial_null() so in case
108  * the driver is not compiled in, the function is still declared and can
109  * be used, but aliases to serial_null() and thus is optimized away.
110  */
111 #define serial_initfunc(name)					\
112 	void name(void)						\
113 		__attribute__((weak, alias("serial_null")));
114 
115 serial_initfunc(mpc8xx_serial_initialize);
116 serial_initfunc(ns16550_serial_initialize);
117 serial_initfunc(pxa_serial_initialize);
118 serial_initfunc(s3c24xx_serial_initialize);
119 serial_initfunc(s5p_serial_initialize);
120 serial_initfunc(zynq_serial_initalize);
121 serial_initfunc(bfin_serial_initialize);
122 serial_initfunc(bfin_jtag_initialize);
123 serial_initfunc(mpc512x_serial_initialize);
124 serial_initfunc(uartlite_serial_initialize);
125 serial_initfunc(au1x00_serial_initialize);
126 serial_initfunc(asc_serial_initialize);
127 serial_initfunc(jz_serial_initialize);
128 serial_initfunc(mpc5xx_serial_initialize);
129 serial_initfunc(mpc8260_scc_serial_initialize);
130 serial_initfunc(mpc8260_smc_serial_initialize);
131 serial_initfunc(mpc85xx_serial_initialize);
132 serial_initfunc(iop480_serial_initialize);
133 serial_initfunc(leon2_serial_initialize);
134 serial_initfunc(leon3_serial_initialize);
135 serial_initfunc(marvell_serial_initialize);
136 serial_initfunc(amirix_serial_initialize);
137 serial_initfunc(bmw_serial_initialize);
138 serial_initfunc(cogent_serial_initialize);
139 serial_initfunc(cpci750_serial_initialize);
140 serial_initfunc(evb64260_serial_initialize);
141 serial_initfunc(ml2_serial_initialize);
142 serial_initfunc(sconsole_serial_initialize);
143 serial_initfunc(p3mx_serial_initialize);
144 serial_initfunc(altera_jtag_serial_initialize);
145 serial_initfunc(altera_serial_initialize);
146 serial_initfunc(atmel_serial_initialize);
147 serial_initfunc(lpc32xx_serial_initialize);
148 serial_initfunc(mcf_serial_initialize);
149 serial_initfunc(oc_serial_initialize);
150 serial_initfunc(sandbox_serial_initialize);
151 serial_initfunc(clps7111_serial_initialize);
152 serial_initfunc(imx_serial_initialize);
153 serial_initfunc(ixp_serial_initialize);
154 serial_initfunc(ks8695_serial_initialize);
155 serial_initfunc(lh7a40x_serial_initialize);
156 serial_initfunc(max3100_serial_initialize);
157 serial_initfunc(mxc_serial_initialize);
158 serial_initfunc(pl01x_serial_initialize);
159 serial_initfunc(s3c44b0_serial_initialize);
160 serial_initfunc(sa1100_serial_initialize);
161 serial_initfunc(sh_serial_initialize);
162 
163 /**
164  * serial_register() - Register serial driver with serial driver core
165  * @dev:	Pointer to the serial driver structure
166  *
167  * This function registers the serial driver supplied via @dev with
168  * serial driver core, thus making U-Boot aware of it and making it
169  * available for U-Boot to use. On platforms that still require manual
170  * relocation of constant variables, relocation of the supplied structure
171  * is performed.
172  */
173 void serial_register(struct serial_device *dev)
174 {
175 #ifdef CONFIG_NEEDS_MANUAL_RELOC
176 	if (dev->start)
177 		dev->start += gd->reloc_off;
178 	if (dev->stop)
179 		dev->stop += gd->reloc_off;
180 	if (dev->setbrg)
181 		dev->setbrg += gd->reloc_off;
182 	if (dev->getc)
183 		dev->getc += gd->reloc_off;
184 	if (dev->tstc)
185 		dev->tstc += gd->reloc_off;
186 	if (dev->putc)
187 		dev->putc += gd->reloc_off;
188 	if (dev->puts)
189 		dev->puts += gd->reloc_off;
190 #endif
191 
192 	dev->next = serial_devices;
193 	serial_devices = dev;
194 }
195 
196 /**
197  * serial_initialize() - Register all compiled-in serial port drivers
198  *
199  * This function registers all serial port drivers that are compiled
200  * into the U-Boot binary with the serial core, thus making them
201  * available to U-Boot to use. Lastly, this function assigns a default
202  * serial port to the serial core. That serial port is then used as a
203  * default output.
204  */
205 void serial_initialize(void)
206 {
207 	mpc8xx_serial_initialize();
208 	ns16550_serial_initialize();
209 	pxa_serial_initialize();
210 	s3c24xx_serial_initialize();
211 	s5p_serial_initialize();
212 	mpc512x_serial_initialize();
213 	bfin_serial_initialize();
214 	bfin_jtag_initialize();
215 	uartlite_serial_initialize();
216 	zynq_serial_initalize();
217 	au1x00_serial_initialize();
218 	asc_serial_initialize();
219 	jz_serial_initialize();
220 	mpc5xx_serial_initialize();
221 	mpc8260_scc_serial_initialize();
222 	mpc8260_smc_serial_initialize();
223 	mpc85xx_serial_initialize();
224 	iop480_serial_initialize();
225 	leon2_serial_initialize();
226 	leon3_serial_initialize();
227 	marvell_serial_initialize();
228 	amirix_serial_initialize();
229 	bmw_serial_initialize();
230 	cogent_serial_initialize();
231 	cpci750_serial_initialize();
232 	evb64260_serial_initialize();
233 	ml2_serial_initialize();
234 	sconsole_serial_initialize();
235 	p3mx_serial_initialize();
236 	altera_jtag_serial_initialize();
237 	altera_serial_initialize();
238 	atmel_serial_initialize();
239 	lpc32xx_serial_initialize();
240 	mcf_serial_initialize();
241 	oc_serial_initialize();
242 	sandbox_serial_initialize();
243 	clps7111_serial_initialize();
244 	imx_serial_initialize();
245 	ixp_serial_initialize();
246 	ks8695_serial_initialize();
247 	lh7a40x_serial_initialize();
248 	max3100_serial_initialize();
249 	mxc_serial_initialize();
250 	pl01x_serial_initialize();
251 	s3c44b0_serial_initialize();
252 	sa1100_serial_initialize();
253 	sh_serial_initialize();
254 
255 	serial_assign(default_serial_console()->name);
256 }
257 
258 /**
259  * serial_stdio_init() - Register serial ports with STDIO core
260  *
261  * This function generates a proxy driver for each serial port driver.
262  * These proxy drivers then register with the STDIO core, making the
263  * serial drivers available as STDIO devices.
264  */
265 void serial_stdio_init(void)
266 {
267 	struct stdio_dev dev;
268 	struct serial_device *s = serial_devices;
269 
270 	while (s) {
271 		memset(&dev, 0, sizeof(dev));
272 
273 		strcpy(dev.name, s->name);
274 		dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
275 
276 		dev.start = s->start;
277 		dev.stop = s->stop;
278 		dev.putc = s->putc;
279 		dev.puts = s->puts;
280 		dev.getc = s->getc;
281 		dev.tstc = s->tstc;
282 
283 		stdio_register(&dev);
284 
285 		s = s->next;
286 	}
287 }
288 
289 /**
290  * serial_assign() - Select the serial output device by name
291  * @name:	Name of the serial driver to be used as default output
292  *
293  * This function configures the serial output multiplexing by
294  * selecting which serial device will be used as default. In case
295  * the STDIO "serial" device is selected as stdin/stdout/stderr,
296  * the serial device previously configured by this function will be
297  * used for the particular operation.
298  *
299  * Returns 0 on success, negative on error.
300  */
301 int serial_assign(const char *name)
302 {
303 	struct serial_device *s;
304 
305 	for (s = serial_devices; s; s = s->next) {
306 		if (strcmp(s->name, name))
307 			continue;
308 		serial_current = s;
309 		return 0;
310 	}
311 
312 	return -EINVAL;
313 }
314 
315 /**
316  * serial_reinit_all() - Reinitialize all compiled-in serial ports
317  *
318  * This function reinitializes all serial ports that are compiled
319  * into U-Boot by calling their serial_start() functions.
320  */
321 void serial_reinit_all(void)
322 {
323 	struct serial_device *s;
324 
325 	for (s = serial_devices; s; s = s->next)
326 		s->start();
327 }
328 
329 /**
330  * get_current() - Return pointer to currently selected serial port
331  *
332  * This function returns a pointer to currently selected serial port.
333  * The currently selected serial port is altered by serial_assign()
334  * function.
335  *
336  * In case this function is called before relocation or before any serial
337  * port is configured, this function calls default_serial_console() to
338  * determine the serial port. Otherwise, the configured serial port is
339  * returned.
340  *
341  * Returns pointer to the currently selected serial port on success,
342  * NULL on error.
343  */
344 static struct serial_device *get_current(void)
345 {
346 	struct serial_device *dev;
347 
348 	if (!(gd->flags & GD_FLG_RELOC))
349 		dev = default_serial_console();
350 	else if (!serial_current)
351 		dev = default_serial_console();
352 	else
353 		dev = serial_current;
354 
355 	/* We must have a console device */
356 	if (!dev) {
357 #ifdef CONFIG_SPL_BUILD
358 		puts("Cannot find console\n");
359 		hang();
360 #else
361 		panic("Cannot find console\n");
362 #endif
363 	}
364 
365 	return dev;
366 }
367 
368 /**
369  * serial_init() - Initialize currently selected serial port
370  *
371  * This function initializes the currently selected serial port. This
372  * usually involves setting up the registers of that particular port,
373  * enabling clock and such. This function uses the get_current() call
374  * to determine which port is selected.
375  *
376  * Returns 0 on success, negative on error.
377  */
378 int serial_init(void)
379 {
380 	return get_current()->start();
381 }
382 
383 /**
384  * serial_setbrg() - Configure baud-rate of currently selected serial port
385  *
386  * This function configures the baud-rate of the currently selected
387  * serial port. The baud-rate is retrieved from global data within
388  * the serial port driver. This function uses the get_current() call
389  * to determine which port is selected.
390  *
391  * Returns 0 on success, negative on error.
392  */
393 void serial_setbrg(void)
394 {
395 	get_current()->setbrg();
396 }
397 
398 /**
399  * serial_getc() - Read character from currently selected serial port
400  *
401  * This function retrieves a character from currently selected serial
402  * port. In case there is no character waiting on the serial port,
403  * this function will block and wait for the character to appear. This
404  * function uses the get_current() call to determine which port is
405  * selected.
406  *
407  * Returns the character on success, negative on error.
408  */
409 int serial_getc(void)
410 {
411 	return get_current()->getc();
412 }
413 
414 /**
415  * serial_tstc() - Test if data is available on currently selected serial port
416  *
417  * This function tests if one or more characters are available on
418  * currently selected serial port. This function never blocks. This
419  * function uses the get_current() call to determine which port is
420  * selected.
421  *
422  * Returns positive if character is available, zero otherwise.
423  */
424 int serial_tstc(void)
425 {
426 	return get_current()->tstc();
427 }
428 
429 /**
430  * serial_putc() - Output character via currently selected serial port
431  * @c:	Single character to be output from the serial port.
432  *
433  * This function outputs a character via currently selected serial
434  * port. This character is passed to the serial port driver responsible
435  * for controlling the hardware. The hardware may still be in process
436  * of transmitting another character, therefore this function may block
437  * for a short amount of time. This function uses the get_current()
438  * call to determine which port is selected.
439  */
440 void serial_putc(const char c)
441 {
442 	get_current()->putc(c);
443 }
444 
445 /**
446  * serial_puts() - Output string via currently selected serial port
447  * @s:	Zero-terminated string to be output from the serial port.
448  *
449  * This function outputs a zero-terminated string via currently
450  * selected serial port. This function behaves as an accelerator
451  * in case the hardware can queue multiple characters for transfer.
452  * The whole string that is to be output is available to the function
453  * implementing the hardware manipulation. Transmitting the whole
454  * string may take some time, thus this function may block for some
455  * amount of time. This function uses the get_current() call to
456  * determine which port is selected.
457  */
458 void serial_puts(const char *s)
459 {
460 	get_current()->puts(s);
461 }
462 
463 /**
464  * default_serial_puts() - Output string by calling serial_putc() in loop
465  * @s:	Zero-terminated string to be output from the serial port.
466  *
467  * This function outputs a zero-terminated string by calling serial_putc()
468  * in a loop. Most drivers do not support queueing more than one byte for
469  * transfer, thus this function precisely implements their serial_puts().
470  *
471  * To optimize the number of get_current() calls, this function only
472  * calls get_current() once and then directly accesses the putc() call
473  * of the &struct serial_device .
474  */
475 void default_serial_puts(const char *s)
476 {
477 	struct serial_device *dev = get_current();
478 	while (*s)
479 		dev->putc(*s++);
480 }
481 
482 #if CONFIG_POST & CONFIG_SYS_POST_UART
483 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
484 
485 /**
486  * uart_post_test() - Test the currently selected serial port using POST
487  * @flags:	POST framework flags
488  *
489  * Do a loopback test of the currently selected serial port. This
490  * function is only useful in the context of the POST testing framwork.
491  * The serial port is firstly configured into loopback mode and then
492  * characters are sent through it.
493  *
494  * Returns 0 on success, value otherwise.
495  */
496 /* Mark weak until post/cpu/.../uart.c migrate over */
497 __weak
498 int uart_post_test(int flags)
499 {
500 	unsigned char c;
501 	int ret, saved_baud, b;
502 	struct serial_device *saved_dev, *s;
503 	bd_t *bd = gd->bd;
504 
505 	/* Save current serial state */
506 	ret = 0;
507 	saved_dev = serial_current;
508 	saved_baud = bd->bi_baudrate;
509 
510 	for (s = serial_devices; s; s = s->next) {
511 		/* If this driver doesn't support loop back, skip it */
512 		if (!s->loop)
513 			continue;
514 
515 		/* Test the next device */
516 		serial_current = s;
517 
518 		ret = serial_init();
519 		if (ret)
520 			goto done;
521 
522 		/* Consume anything that happens to be queued */
523 		while (serial_tstc())
524 			serial_getc();
525 
526 		/* Enable loop back */
527 		s->loop(1);
528 
529 		/* Test every available baud rate */
530 		for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
531 			bd->bi_baudrate = bauds[b];
532 			serial_setbrg();
533 
534 			/*
535 			 * Stick to printable chars to avoid issues:
536 			 *  - terminal corruption
537 			 *  - serial program reacting to sequences and sending
538 			 *    back random extra data
539 			 *  - most serial drivers add in extra chars (like \r\n)
540 			 */
541 			for (c = 0x20; c < 0x7f; ++c) {
542 				/* Send it out */
543 				serial_putc(c);
544 
545 				/* Make sure it's the same one */
546 				ret = (c != serial_getc());
547 				if (ret) {
548 					s->loop(0);
549 					goto done;
550 				}
551 
552 				/* Clean up the output in case it was sent */
553 				serial_putc('\b');
554 				ret = ('\b' != serial_getc());
555 				if (ret) {
556 					s->loop(0);
557 					goto done;
558 				}
559 			}
560 		}
561 
562 		/* Disable loop back */
563 		s->loop(0);
564 
565 		/* XXX: There is no serial_stop() !? */
566 		if (s->stop)
567 			s->stop();
568 	}
569 
570  done:
571 	/* Restore previous serial state */
572 	serial_current = saved_dev;
573 	bd->bi_baudrate = saved_baud;
574 	serial_reinit_all();
575 	serial_setbrg();
576 
577 	return ret;
578 }
579 #endif
580