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_setconfig(uint config)
298 {
299 	struct dm_serial_ops *ops;
300 
301 	if (!gd->cur_serial_dev)
302 		return 0;
303 
304 	ops = serial_get_ops(gd->cur_serial_dev);
305 	if (ops->setconfig)
306 		return ops->setconfig(gd->cur_serial_dev, config);
307 
308 	return 0;
309 }
310 
311 void serial_stdio_init(void)
312 {
313 }
314 
315 #if defined(CONFIG_DM_STDIO)
316 
317 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
318 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
319 {
320 	_serial_putc(sdev->priv, ch);
321 }
322 #endif
323 
324 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
325 {
326 	_serial_puts(sdev->priv, str);
327 }
328 
329 static int serial_stub_getc(struct stdio_dev *sdev)
330 {
331 	return _serial_getc(sdev->priv);
332 }
333 
334 static int serial_stub_tstc(struct stdio_dev *sdev)
335 {
336 	return _serial_tstc(sdev->priv);
337 }
338 #endif
339 
340 /**
341  * on_baudrate() - Update the actual baudrate when the env var changes
342  *
343  * This will check for a valid baudrate and only apply it if valid.
344  */
345 static int on_baudrate(const char *name, const char *value, enum env_op op,
346 	int flags)
347 {
348 	int i;
349 	int baudrate;
350 
351 	switch (op) {
352 	case env_op_create:
353 	case env_op_overwrite:
354 		/*
355 		 * Switch to new baudrate if new baudrate is supported
356 		 */
357 		baudrate = simple_strtoul(value, NULL, 10);
358 
359 		/* Not actually changing */
360 		if (gd->baudrate == baudrate)
361 			return 0;
362 
363 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
364 			if (baudrate == baudrate_table[i])
365 				break;
366 		}
367 		if (i == ARRAY_SIZE(baudrate_table)) {
368 			if ((flags & H_FORCE) == 0)
369 				printf("## Baudrate %d bps not supported\n",
370 				       baudrate);
371 			return 1;
372 		}
373 		if ((flags & H_INTERACTIVE) != 0) {
374 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
375 			       baudrate);
376 			udelay(50000);
377 		}
378 
379 		gd->baudrate = baudrate;
380 
381 		serial_setbrg();
382 
383 		udelay(50000);
384 
385 		if ((flags & H_INTERACTIVE) != 0)
386 			while (1) {
387 				if (getc() == '\r')
388 					break;
389 			}
390 
391 		return 0;
392 	case env_op_delete:
393 		printf("## Baudrate may not be deleted\n");
394 		return 1;
395 	default:
396 		return 0;
397 	}
398 }
399 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
400 
401 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
402 static int serial_post_probe(struct udevice *dev)
403 {
404 	struct dm_serial_ops *ops = serial_get_ops(dev);
405 #ifdef CONFIG_DM_STDIO
406 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
407 	struct stdio_dev sdev;
408 #endif
409 	int ret;
410 
411 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
412 	if (ops->setbrg)
413 		ops->setbrg += gd->reloc_off;
414 	if (ops->getc)
415 		ops->getc += gd->reloc_off;
416 	if (ops->putc)
417 		ops->putc += gd->reloc_off;
418 	if (ops->pending)
419 		ops->pending += gd->reloc_off;
420 	if (ops->clear)
421 		ops->clear += gd->reloc_off;
422 	if (ops->setconfig)
423 		ops->setconfig += gd->reloc_off;
424 #if CONFIG_POST & CONFIG_SYS_POST_UART
425 	if (ops->loop)
426 		ops->loop += gd->reloc_off;
427 #endif
428 #endif
429 	/* Set the baud rate */
430 	if (ops->setbrg) {
431 		ret = ops->setbrg(dev, gd->baudrate);
432 		if (ret)
433 			return ret;
434 	}
435 
436 #ifdef CONFIG_DM_STDIO
437 	if (!(gd->flags & GD_FLG_RELOC))
438 		return 0;
439 	memset(&sdev, '\0', sizeof(sdev));
440 
441 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
442 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_DM;
443 	sdev.priv = dev;
444 	sdev.putc = serial_stub_putc;
445 	sdev.puts = serial_stub_puts;
446 	sdev.getc = serial_stub_getc;
447 	sdev.tstc = serial_stub_tstc;
448 
449 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
450 	/* Allocate the RX buffer */
451 	upriv->buf = malloc(CONFIG_SERIAL_RX_BUFFER_SIZE);
452 #endif
453 
454 	stdio_register_dev(&sdev, &upriv->sdev);
455 #endif
456 	return 0;
457 }
458 
459 static int serial_pre_remove(struct udevice *dev)
460 {
461 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
462 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
463 
464 	if (stdio_deregister_dev(upriv->sdev, true))
465 		return -EPERM;
466 #endif
467 
468 	return 0;
469 }
470 
471 UCLASS_DRIVER(serial) = {
472 	.id		= UCLASS_SERIAL,
473 	.name		= "serial",
474 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
475 	.post_probe	= serial_post_probe,
476 	.pre_remove	= serial_pre_remove,
477 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
478 };
479 #endif
480