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