xref: /openbmc/u-boot/drivers/serial/serial.c (revision 47f75cf2)
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 serial_initfunc(arm_dcc_initialize);
163 serial_initfunc(mxs_auart_initialize);
164 
165 /**
166  * serial_register() - Register serial driver with serial driver core
167  * @dev:	Pointer to the serial driver structure
168  *
169  * This function registers the serial driver supplied via @dev with
170  * serial driver core, thus making U-Boot aware of it and making it
171  * available for U-Boot to use. On platforms that still require manual
172  * relocation of constant variables, relocation of the supplied structure
173  * is performed.
174  */
175 void serial_register(struct serial_device *dev)
176 {
177 #ifdef CONFIG_NEEDS_MANUAL_RELOC
178 	if (dev->start)
179 		dev->start += gd->reloc_off;
180 	if (dev->stop)
181 		dev->stop += gd->reloc_off;
182 	if (dev->setbrg)
183 		dev->setbrg += gd->reloc_off;
184 	if (dev->getc)
185 		dev->getc += gd->reloc_off;
186 	if (dev->tstc)
187 		dev->tstc += gd->reloc_off;
188 	if (dev->putc)
189 		dev->putc += gd->reloc_off;
190 	if (dev->puts)
191 		dev->puts += gd->reloc_off;
192 #endif
193 
194 	dev->next = serial_devices;
195 	serial_devices = dev;
196 }
197 
198 /**
199  * serial_initialize() - Register all compiled-in serial port drivers
200  *
201  * This function registers all serial port drivers that are compiled
202  * into the U-Boot binary with the serial core, thus making them
203  * available to U-Boot to use. Lastly, this function assigns a default
204  * serial port to the serial core. That serial port is then used as a
205  * default output.
206  */
207 void serial_initialize(void)
208 {
209 	mpc8xx_serial_initialize();
210 	ns16550_serial_initialize();
211 	pxa_serial_initialize();
212 	s3c24xx_serial_initialize();
213 	s5p_serial_initialize();
214 	mpc512x_serial_initialize();
215 	bfin_serial_initialize();
216 	bfin_jtag_initialize();
217 	uartlite_serial_initialize();
218 	zynq_serial_initalize();
219 	au1x00_serial_initialize();
220 	asc_serial_initialize();
221 	jz_serial_initialize();
222 	mpc5xx_serial_initialize();
223 	mpc8260_scc_serial_initialize();
224 	mpc8260_smc_serial_initialize();
225 	mpc85xx_serial_initialize();
226 	iop480_serial_initialize();
227 	leon2_serial_initialize();
228 	leon3_serial_initialize();
229 	marvell_serial_initialize();
230 	amirix_serial_initialize();
231 	bmw_serial_initialize();
232 	cogent_serial_initialize();
233 	cpci750_serial_initialize();
234 	evb64260_serial_initialize();
235 	ml2_serial_initialize();
236 	sconsole_serial_initialize();
237 	p3mx_serial_initialize();
238 	altera_jtag_serial_initialize();
239 	altera_serial_initialize();
240 	atmel_serial_initialize();
241 	lpc32xx_serial_initialize();
242 	mcf_serial_initialize();
243 	oc_serial_initialize();
244 	sandbox_serial_initialize();
245 	clps7111_serial_initialize();
246 	imx_serial_initialize();
247 	ixp_serial_initialize();
248 	ks8695_serial_initialize();
249 	lh7a40x_serial_initialize();
250 	max3100_serial_initialize();
251 	mxc_serial_initialize();
252 	pl01x_serial_initialize();
253 	s3c44b0_serial_initialize();
254 	sa1100_serial_initialize();
255 	sh_serial_initialize();
256 	arm_dcc_initialize();
257 	mxs_auart_initialize();
258 
259 	serial_assign(default_serial_console()->name);
260 }
261 
262 /**
263  * serial_stdio_init() - Register serial ports with STDIO core
264  *
265  * This function generates a proxy driver for each serial port driver.
266  * These proxy drivers then register with the STDIO core, making the
267  * serial drivers available as STDIO devices.
268  */
269 void serial_stdio_init(void)
270 {
271 	struct stdio_dev dev;
272 	struct serial_device *s = serial_devices;
273 
274 	while (s) {
275 		memset(&dev, 0, sizeof(dev));
276 
277 		strcpy(dev.name, s->name);
278 		dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
279 
280 		dev.start = s->start;
281 		dev.stop = s->stop;
282 		dev.putc = s->putc;
283 		dev.puts = s->puts;
284 		dev.getc = s->getc;
285 		dev.tstc = s->tstc;
286 
287 		stdio_register(&dev);
288 
289 		s = s->next;
290 	}
291 }
292 
293 /**
294  * serial_assign() - Select the serial output device by name
295  * @name:	Name of the serial driver to be used as default output
296  *
297  * This function configures the serial output multiplexing by
298  * selecting which serial device will be used as default. In case
299  * the STDIO "serial" device is selected as stdin/stdout/stderr,
300  * the serial device previously configured by this function will be
301  * used for the particular operation.
302  *
303  * Returns 0 on success, negative on error.
304  */
305 int serial_assign(const char *name)
306 {
307 	struct serial_device *s;
308 
309 	for (s = serial_devices; s; s = s->next) {
310 		if (strcmp(s->name, name))
311 			continue;
312 		serial_current = s;
313 		return 0;
314 	}
315 
316 	return -EINVAL;
317 }
318 
319 /**
320  * serial_reinit_all() - Reinitialize all compiled-in serial ports
321  *
322  * This function reinitializes all serial ports that are compiled
323  * into U-Boot by calling their serial_start() functions.
324  */
325 void serial_reinit_all(void)
326 {
327 	struct serial_device *s;
328 
329 	for (s = serial_devices; s; s = s->next)
330 		s->start();
331 }
332 
333 /**
334  * get_current() - Return pointer to currently selected serial port
335  *
336  * This function returns a pointer to currently selected serial port.
337  * The currently selected serial port is altered by serial_assign()
338  * function.
339  *
340  * In case this function is called before relocation or before any serial
341  * port is configured, this function calls default_serial_console() to
342  * determine the serial port. Otherwise, the configured serial port is
343  * returned.
344  *
345  * Returns pointer to the currently selected serial port on success,
346  * NULL on error.
347  */
348 static struct serial_device *get_current(void)
349 {
350 	struct serial_device *dev;
351 
352 	if (!(gd->flags & GD_FLG_RELOC))
353 		dev = default_serial_console();
354 	else if (!serial_current)
355 		dev = default_serial_console();
356 	else
357 		dev = serial_current;
358 
359 	/* We must have a console device */
360 	if (!dev) {
361 #ifdef CONFIG_SPL_BUILD
362 		puts("Cannot find console\n");
363 		hang();
364 #else
365 		panic("Cannot find console\n");
366 #endif
367 	}
368 
369 	return dev;
370 }
371 
372 /**
373  * serial_init() - Initialize currently selected serial port
374  *
375  * This function initializes the currently selected serial port. This
376  * usually involves setting up the registers of that particular port,
377  * enabling clock and such. This function uses the get_current() call
378  * to determine which port is selected.
379  *
380  * Returns 0 on success, negative on error.
381  */
382 int serial_init(void)
383 {
384 	return get_current()->start();
385 }
386 
387 /**
388  * serial_setbrg() - Configure baud-rate of currently selected serial port
389  *
390  * This function configures the baud-rate of the currently selected
391  * serial port. The baud-rate is retrieved from global data within
392  * the serial port driver. This function uses the get_current() call
393  * to determine which port is selected.
394  *
395  * Returns 0 on success, negative on error.
396  */
397 void serial_setbrg(void)
398 {
399 	get_current()->setbrg();
400 }
401 
402 /**
403  * serial_getc() - Read character from currently selected serial port
404  *
405  * This function retrieves a character from currently selected serial
406  * port. In case there is no character waiting on the serial port,
407  * this function will block and wait for the character to appear. This
408  * function uses the get_current() call to determine which port is
409  * selected.
410  *
411  * Returns the character on success, negative on error.
412  */
413 int serial_getc(void)
414 {
415 	return get_current()->getc();
416 }
417 
418 /**
419  * serial_tstc() - Test if data is available on currently selected serial port
420  *
421  * This function tests if one or more characters are available on
422  * currently selected serial port. This function never blocks. This
423  * function uses the get_current() call to determine which port is
424  * selected.
425  *
426  * Returns positive if character is available, zero otherwise.
427  */
428 int serial_tstc(void)
429 {
430 	return get_current()->tstc();
431 }
432 
433 /**
434  * serial_putc() - Output character via currently selected serial port
435  * @c:	Single character to be output from the serial port.
436  *
437  * This function outputs a character via currently selected serial
438  * port. This character is passed to the serial port driver responsible
439  * for controlling the hardware. The hardware may still be in process
440  * of transmitting another character, therefore this function may block
441  * for a short amount of time. This function uses the get_current()
442  * call to determine which port is selected.
443  */
444 void serial_putc(const char c)
445 {
446 	get_current()->putc(c);
447 }
448 
449 /**
450  * serial_puts() - Output string via currently selected serial port
451  * @s:	Zero-terminated string to be output from the serial port.
452  *
453  * This function outputs a zero-terminated string via currently
454  * selected serial port. This function behaves as an accelerator
455  * in case the hardware can queue multiple characters for transfer.
456  * The whole string that is to be output is available to the function
457  * implementing the hardware manipulation. Transmitting the whole
458  * string may take some time, thus this function may block for some
459  * amount of time. This function uses the get_current() call to
460  * determine which port is selected.
461  */
462 void serial_puts(const char *s)
463 {
464 	get_current()->puts(s);
465 }
466 
467 /**
468  * default_serial_puts() - Output string by calling serial_putc() in loop
469  * @s:	Zero-terminated string to be output from the serial port.
470  *
471  * This function outputs a zero-terminated string by calling serial_putc()
472  * in a loop. Most drivers do not support queueing more than one byte for
473  * transfer, thus this function precisely implements their serial_puts().
474  *
475  * To optimize the number of get_current() calls, this function only
476  * calls get_current() once and then directly accesses the putc() call
477  * of the &struct serial_device .
478  */
479 void default_serial_puts(const char *s)
480 {
481 	struct serial_device *dev = get_current();
482 	while (*s)
483 		dev->putc(*s++);
484 }
485 
486 #if CONFIG_POST & CONFIG_SYS_POST_UART
487 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
488 
489 /**
490  * uart_post_test() - Test the currently selected serial port using POST
491  * @flags:	POST framework flags
492  *
493  * Do a loopback test of the currently selected serial port. This
494  * function is only useful in the context of the POST testing framwork.
495  * The serial port is firstly configured into loopback mode and then
496  * characters are sent through it.
497  *
498  * Returns 0 on success, value otherwise.
499  */
500 /* Mark weak until post/cpu/.../uart.c migrate over */
501 __weak
502 int uart_post_test(int flags)
503 {
504 	unsigned char c;
505 	int ret, saved_baud, b;
506 	struct serial_device *saved_dev, *s;
507 	bd_t *bd = gd->bd;
508 
509 	/* Save current serial state */
510 	ret = 0;
511 	saved_dev = serial_current;
512 	saved_baud = bd->bi_baudrate;
513 
514 	for (s = serial_devices; s; s = s->next) {
515 		/* If this driver doesn't support loop back, skip it */
516 		if (!s->loop)
517 			continue;
518 
519 		/* Test the next device */
520 		serial_current = s;
521 
522 		ret = serial_init();
523 		if (ret)
524 			goto done;
525 
526 		/* Consume anything that happens to be queued */
527 		while (serial_tstc())
528 			serial_getc();
529 
530 		/* Enable loop back */
531 		s->loop(1);
532 
533 		/* Test every available baud rate */
534 		for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
535 			bd->bi_baudrate = bauds[b];
536 			serial_setbrg();
537 
538 			/*
539 			 * Stick to printable chars to avoid issues:
540 			 *  - terminal corruption
541 			 *  - serial program reacting to sequences and sending
542 			 *    back random extra data
543 			 *  - most serial drivers add in extra chars (like \r\n)
544 			 */
545 			for (c = 0x20; c < 0x7f; ++c) {
546 				/* Send it out */
547 				serial_putc(c);
548 
549 				/* Make sure it's the same one */
550 				ret = (c != serial_getc());
551 				if (ret) {
552 					s->loop(0);
553 					goto done;
554 				}
555 
556 				/* Clean up the output in case it was sent */
557 				serial_putc('\b');
558 				ret = ('\b' != serial_getc());
559 				if (ret) {
560 					s->loop(0);
561 					goto done;
562 				}
563 			}
564 		}
565 
566 		/* Disable loop back */
567 		s->loop(0);
568 
569 		/* XXX: There is no serial_stop() !? */
570 		if (s->stop)
571 			s->stop();
572 	}
573 
574  done:
575 	/* Restore previous serial state */
576 	serial_current = saved_dev;
577 	bd->bi_baudrate = saved_baud;
578 	serial_reinit_all();
579 	serial_setbrg();
580 
581 	return ret;
582 }
583 #endif
584