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