1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2014 The Chromium OS Authors.
4  */
5 
6 #include <common.h>
7 #include <dm.h>
8 #include <environment.h>
9 #include <errno.h>
10 #include <os.h>
11 #include <serial.h>
12 #include <stdio_dev.h>
13 #include <watchdog.h>
14 #include <dm/lists.h>
15 #include <dm/device-internal.h>
16 #include <dm/of_access.h>
17 
18 DECLARE_GLOBAL_DATA_PTR;
19 
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 #if !CONFIG_VAL(SYS_MALLOC_F_LEN)
26 #error "Serial is required before relocation - define CONFIG_$(SPL_)SYS_MALLOC_F_LEN to make this work"
27 #endif
28 
29 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
30 static int serial_check_stdout(const void *blob, struct udevice **devp)
31 {
32 	int node;
33 
34 	/* Check for a chosen console */
35 	node = fdtdec_get_chosen_node(blob, "stdout-path");
36 	if (node < 0) {
37 		const char *str, *p, *name;
38 
39 		/*
40 		 * Deal with things like
41 		 *	stdout-path = "serial0:115200n8";
42 		 *
43 		 * We need to look up the alias and then follow it to the
44 		 * correct node.
45 		 */
46 		str = fdtdec_get_chosen_prop(blob, "stdout-path");
47 		if (str) {
48 			p = strchr(str, ':');
49 			name = fdt_get_alias_namelen(blob, str,
50 					p ? p - str : strlen(str));
51 			if (name)
52 				node = fdt_path_offset(blob, name);
53 		}
54 	}
55 	if (node < 0)
56 		node = fdt_path_offset(blob, "console");
57 	if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, devp))
58 		return 0;
59 
60 	/*
61 	 * If the console is not marked to be bound before relocation, bind it
62 	 * anyway.
63 	 */
64 	if (node > 0 && !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
65 					devp, false)) {
66 		if (!device_probe(*devp))
67 			return 0;
68 	}
69 
70 	return -ENODEV;
71 }
72 
73 static void serial_find_console_or_panic(void)
74 {
75 	const void *blob = gd->fdt_blob;
76 	struct udevice *dev;
77 #ifdef CONFIG_SERIAL_SEARCH_ALL
78 	int ret;
79 #endif
80 
81 	if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
82 		uclass_first_device(UCLASS_SERIAL, &dev);
83 		if (dev) {
84 			gd->cur_serial_dev = dev;
85 			return;
86 		}
87 	} else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
88 		/* Live tree has support for stdout */
89 		if (of_live_active()) {
90 			struct device_node *np = of_get_stdout();
91 
92 			if (np && !uclass_get_device_by_ofnode(UCLASS_SERIAL,
93 					np_to_ofnode(np), &dev)) {
94 				gd->cur_serial_dev = dev;
95 				return;
96 			}
97 		} else {
98 			if (!serial_check_stdout(blob, &dev)) {
99 				gd->cur_serial_dev = dev;
100 				return;
101 			}
102 		}
103 	}
104 	if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
105 		/*
106 		 * Try to use CONFIG_CONS_INDEX if available (it is numbered
107 		 * from 1!).
108 		 *
109 		 * Failing that, get the device with sequence number 0, or in
110 		 * extremis just the first working serial device we can find.
111 		 * But we insist on having a console (even if it is silent).
112 		 */
113 #ifdef CONFIG_CONS_INDEX
114 #define INDEX (CONFIG_CONS_INDEX - 1)
115 #else
116 #define INDEX 0
117 #endif
118 
119 #ifdef CONFIG_SERIAL_SEARCH_ALL
120 		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
121 		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev)) {
122 			if (dev->flags & DM_FLAG_ACTIVATED) {
123 				gd->cur_serial_dev = dev;
124 				return;
125 			}
126 		}
127 
128 		/* Search for any working device */
129 		for (ret = uclass_first_device_check(UCLASS_SERIAL, &dev);
130 		     dev;
131 		     ret = uclass_next_device_check(&dev)) {
132 			if (!ret) {
133 				/* Device did succeed probing */
134 				gd->cur_serial_dev = dev;
135 				return;
136 			}
137 		}
138 #else
139 		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
140 		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
141 		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
142 			gd->cur_serial_dev = dev;
143 			return;
144 		}
145 #endif
146 
147 #undef INDEX
148 	}
149 
150 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
151 	panic_str("No serial driver found");
152 #endif
153 }
154 #endif /* CONFIG_SERIAL_PRESENT */
155 
156 /* Called prior to relocation */
157 int serial_init(void)
158 {
159 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
160 	serial_find_console_or_panic();
161 	gd->flags |= GD_FLG_SERIAL_READY;
162 #endif
163 
164 	return 0;
165 }
166 
167 /* Called after relocation */
168 void serial_initialize(void)
169 {
170 	serial_init();
171 }
172 
173 static void _serial_putc(struct udevice *dev, char ch)
174 {
175 	struct dm_serial_ops *ops = serial_get_ops(dev);
176 	int err;
177 
178 	if (ch == '\n')
179 		_serial_putc(dev, '\r');
180 
181 	do {
182 		err = ops->putc(dev, ch);
183 	} while (err == -EAGAIN);
184 }
185 
186 static void _serial_puts(struct udevice *dev, const char *str)
187 {
188 	while (*str)
189 		_serial_putc(dev, *str++);
190 }
191 
192 static int __serial_getc(struct udevice *dev)
193 {
194 	struct dm_serial_ops *ops = serial_get_ops(dev);
195 	int err;
196 
197 	do {
198 		err = ops->getc(dev);
199 		if (err == -EAGAIN)
200 			WATCHDOG_RESET();
201 	} while (err == -EAGAIN);
202 
203 	return err >= 0 ? err : 0;
204 }
205 
206 static int __serial_tstc(struct udevice *dev)
207 {
208 	struct dm_serial_ops *ops = serial_get_ops(dev);
209 
210 	if (ops->pending)
211 		return ops->pending(dev, true);
212 
213 	return 1;
214 }
215 
216 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
217 static int _serial_tstc(struct udevice *dev)
218 {
219 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
220 
221 	/* Read all available chars into the RX buffer */
222 	while (__serial_tstc(dev)) {
223 		upriv->buf[upriv->wr_ptr++] = __serial_getc(dev);
224 		upriv->wr_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
225 	}
226 
227 	return upriv->rd_ptr != upriv->wr_ptr ? 1 : 0;
228 }
229 
230 static int _serial_getc(struct udevice *dev)
231 {
232 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
233 	char val;
234 
235 	if (upriv->rd_ptr == upriv->wr_ptr)
236 		return __serial_getc(dev);
237 
238 	val = upriv->buf[upriv->rd_ptr++];
239 	upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
240 
241 	return val;
242 }
243 
244 #else /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
245 
246 static int _serial_getc(struct udevice *dev)
247 {
248 	return __serial_getc(dev);
249 }
250 
251 static int _serial_tstc(struct udevice *dev)
252 {
253 	return __serial_tstc(dev);
254 }
255 #endif /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
256 
257 void serial_putc(char ch)
258 {
259 	if (gd->cur_serial_dev)
260 		_serial_putc(gd->cur_serial_dev, ch);
261 }
262 
263 void serial_puts(const char *str)
264 {
265 	if (gd->cur_serial_dev)
266 		_serial_puts(gd->cur_serial_dev, str);
267 }
268 
269 int serial_getc(void)
270 {
271 	if (!gd->cur_serial_dev)
272 		return 0;
273 
274 	return _serial_getc(gd->cur_serial_dev);
275 }
276 
277 int serial_tstc(void)
278 {
279 	if (!gd->cur_serial_dev)
280 		return 0;
281 
282 	return _serial_tstc(gd->cur_serial_dev);
283 }
284 
285 void serial_setbrg(void)
286 {
287 	struct dm_serial_ops *ops;
288 
289 	if (!gd->cur_serial_dev)
290 		return;
291 
292 	ops = serial_get_ops(gd->cur_serial_dev);
293 	if (ops->setbrg)
294 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
295 }
296 
297 int serial_getconfig(struct udevice *dev, uint *config)
298 {
299 	struct dm_serial_ops *ops;
300 
301 	ops = serial_get_ops(dev);
302 	if (ops->getconfig)
303 		return ops->getconfig(dev, config);
304 
305 	return 0;
306 }
307 
308 int serial_setconfig(struct udevice *dev, uint config)
309 {
310 	struct dm_serial_ops *ops;
311 
312 	ops = serial_get_ops(dev);
313 	if (ops->setconfig)
314 		return ops->setconfig(dev, config);
315 
316 	return 0;
317 }
318 
319 int serial_getinfo(struct udevice *dev, struct serial_device_info *info)
320 {
321 	struct dm_serial_ops *ops;
322 
323 	if (!info)
324 		return -EINVAL;
325 
326 	info->baudrate = gd->baudrate;
327 
328 	ops = serial_get_ops(dev);
329 	if (ops->getinfo)
330 		return ops->getinfo(dev, info);
331 
332 	return -EINVAL;
333 }
334 
335 void serial_stdio_init(void)
336 {
337 }
338 
339 #if defined(CONFIG_DM_STDIO)
340 
341 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
342 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
343 {
344 	_serial_putc(sdev->priv, ch);
345 }
346 #endif
347 
348 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
349 {
350 	_serial_puts(sdev->priv, str);
351 }
352 
353 static int serial_stub_getc(struct stdio_dev *sdev)
354 {
355 	return _serial_getc(sdev->priv);
356 }
357 
358 static int serial_stub_tstc(struct stdio_dev *sdev)
359 {
360 	return _serial_tstc(sdev->priv);
361 }
362 #endif
363 
364 /**
365  * on_baudrate() - Update the actual baudrate when the env var changes
366  *
367  * This will check for a valid baudrate and only apply it if valid.
368  */
369 static int on_baudrate(const char *name, const char *value, enum env_op op,
370 	int flags)
371 {
372 	int i;
373 	int baudrate;
374 
375 	switch (op) {
376 	case env_op_create:
377 	case env_op_overwrite:
378 		/*
379 		 * Switch to new baudrate if new baudrate is supported
380 		 */
381 		baudrate = simple_strtoul(value, NULL, 10);
382 
383 		/* Not actually changing */
384 		if (gd->baudrate == baudrate)
385 			return 0;
386 
387 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
388 			if (baudrate == baudrate_table[i])
389 				break;
390 		}
391 		if (i == ARRAY_SIZE(baudrate_table)) {
392 			if ((flags & H_FORCE) == 0)
393 				printf("## Baudrate %d bps not supported\n",
394 				       baudrate);
395 			return 1;
396 		}
397 		if ((flags & H_INTERACTIVE) != 0) {
398 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
399 			       baudrate);
400 			udelay(50000);
401 		}
402 
403 		gd->baudrate = baudrate;
404 
405 		serial_setbrg();
406 
407 		udelay(50000);
408 
409 		if ((flags & H_INTERACTIVE) != 0)
410 			while (1) {
411 				if (getc() == '\r')
412 					break;
413 			}
414 
415 		return 0;
416 	case env_op_delete:
417 		printf("## Baudrate may not be deleted\n");
418 		return 1;
419 	default:
420 		return 0;
421 	}
422 }
423 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
424 
425 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
426 static int serial_post_probe(struct udevice *dev)
427 {
428 	struct dm_serial_ops *ops = serial_get_ops(dev);
429 #ifdef CONFIG_DM_STDIO
430 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
431 	struct stdio_dev sdev;
432 #endif
433 	int ret;
434 
435 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
436 	if (ops->setbrg)
437 		ops->setbrg += gd->reloc_off;
438 	if (ops->getc)
439 		ops->getc += gd->reloc_off;
440 	if (ops->putc)
441 		ops->putc += gd->reloc_off;
442 	if (ops->pending)
443 		ops->pending += gd->reloc_off;
444 	if (ops->clear)
445 		ops->clear += gd->reloc_off;
446 	if (ops->getconfig)
447 		ops->getconfig += gd->reloc_off;
448 	if (ops->setconfig)
449 		ops->setconfig += gd->reloc_off;
450 #if CONFIG_POST & CONFIG_SYS_POST_UART
451 	if (ops->loop)
452 		ops->loop += gd->reloc_off;
453 #endif
454 	if (ops->getinfo)
455 		ops->getinfo += gd->reloc_off;
456 #endif
457 	/* Set the baud rate */
458 	if (ops->setbrg) {
459 		ret = ops->setbrg(dev, gd->baudrate);
460 		if (ret)
461 			return ret;
462 	}
463 
464 #ifdef CONFIG_DM_STDIO
465 	if (!(gd->flags & GD_FLG_RELOC))
466 		return 0;
467 	memset(&sdev, '\0', sizeof(sdev));
468 
469 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
470 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_DM;
471 	sdev.priv = dev;
472 	sdev.putc = serial_stub_putc;
473 	sdev.puts = serial_stub_puts;
474 	sdev.getc = serial_stub_getc;
475 	sdev.tstc = serial_stub_tstc;
476 
477 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
478 	/* Allocate the RX buffer */
479 	upriv->buf = malloc(CONFIG_SERIAL_RX_BUFFER_SIZE);
480 #endif
481 
482 	stdio_register_dev(&sdev, &upriv->sdev);
483 #endif
484 	return 0;
485 }
486 
487 static int serial_pre_remove(struct udevice *dev)
488 {
489 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
490 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
491 
492 	if (stdio_deregister_dev(upriv->sdev, true))
493 		return -EPERM;
494 #endif
495 
496 	return 0;
497 }
498 
499 UCLASS_DRIVER(serial) = {
500 	.id		= UCLASS_SERIAL,
501 	.name		= "serial",
502 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
503 	.post_probe	= serial_post_probe,
504 	.pre_remove	= serial_pre_remove,
505 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
506 };
507 #endif
508