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 	val = upriv->buf[upriv->rd_ptr++];
232 	upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
233 
234 	return val;
235 }
236 
237 #else /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
238 
239 static int _serial_getc(struct udevice *dev)
240 {
241 	return __serial_getc(dev);
242 }
243 
244 static int _serial_tstc(struct udevice *dev)
245 {
246 	return __serial_tstc(dev);
247 }
248 #endif /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
249 
250 void serial_putc(char ch)
251 {
252 	if (gd->cur_serial_dev)
253 		_serial_putc(gd->cur_serial_dev, ch);
254 }
255 
256 void serial_puts(const char *str)
257 {
258 	if (gd->cur_serial_dev)
259 		_serial_puts(gd->cur_serial_dev, str);
260 }
261 
262 int serial_getc(void)
263 {
264 	if (!gd->cur_serial_dev)
265 		return 0;
266 
267 	return _serial_getc(gd->cur_serial_dev);
268 }
269 
270 int serial_tstc(void)
271 {
272 	if (!gd->cur_serial_dev)
273 		return 0;
274 
275 	return _serial_tstc(gd->cur_serial_dev);
276 }
277 
278 void serial_setbrg(void)
279 {
280 	struct dm_serial_ops *ops;
281 
282 	if (!gd->cur_serial_dev)
283 		return;
284 
285 	ops = serial_get_ops(gd->cur_serial_dev);
286 	if (ops->setbrg)
287 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
288 }
289 
290 void serial_stdio_init(void)
291 {
292 }
293 
294 #if defined(CONFIG_DM_STDIO)
295 
296 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
297 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
298 {
299 	_serial_putc(sdev->priv, ch);
300 }
301 #endif
302 
303 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
304 {
305 	_serial_puts(sdev->priv, str);
306 }
307 
308 static int serial_stub_getc(struct stdio_dev *sdev)
309 {
310 	return _serial_getc(sdev->priv);
311 }
312 
313 static int serial_stub_tstc(struct stdio_dev *sdev)
314 {
315 	return _serial_tstc(sdev->priv);
316 }
317 #endif
318 
319 /**
320  * on_baudrate() - Update the actual baudrate when the env var changes
321  *
322  * This will check for a valid baudrate and only apply it if valid.
323  */
324 static int on_baudrate(const char *name, const char *value, enum env_op op,
325 	int flags)
326 {
327 	int i;
328 	int baudrate;
329 
330 	switch (op) {
331 	case env_op_create:
332 	case env_op_overwrite:
333 		/*
334 		 * Switch to new baudrate if new baudrate is supported
335 		 */
336 		baudrate = simple_strtoul(value, NULL, 10);
337 
338 		/* Not actually changing */
339 		if (gd->baudrate == baudrate)
340 			return 0;
341 
342 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
343 			if (baudrate == baudrate_table[i])
344 				break;
345 		}
346 		if (i == ARRAY_SIZE(baudrate_table)) {
347 			if ((flags & H_FORCE) == 0)
348 				printf("## Baudrate %d bps not supported\n",
349 				       baudrate);
350 			return 1;
351 		}
352 		if ((flags & H_INTERACTIVE) != 0) {
353 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
354 			       baudrate);
355 			udelay(50000);
356 		}
357 
358 		gd->baudrate = baudrate;
359 
360 		serial_setbrg();
361 
362 		udelay(50000);
363 
364 		if ((flags & H_INTERACTIVE) != 0)
365 			while (1) {
366 				if (getc() == '\r')
367 					break;
368 			}
369 
370 		return 0;
371 	case env_op_delete:
372 		printf("## Baudrate may not be deleted\n");
373 		return 1;
374 	default:
375 		return 0;
376 	}
377 }
378 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
379 
380 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
381 static int serial_post_probe(struct udevice *dev)
382 {
383 	struct dm_serial_ops *ops = serial_get_ops(dev);
384 #ifdef CONFIG_DM_STDIO
385 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
386 	struct stdio_dev sdev;
387 #endif
388 	int ret;
389 
390 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
391 	if (ops->setbrg)
392 		ops->setbrg += gd->reloc_off;
393 	if (ops->getc)
394 		ops->getc += gd->reloc_off;
395 	if (ops->putc)
396 		ops->putc += gd->reloc_off;
397 	if (ops->pending)
398 		ops->pending += gd->reloc_off;
399 	if (ops->clear)
400 		ops->clear += gd->reloc_off;
401 #if CONFIG_POST & CONFIG_SYS_POST_UART
402 	if (ops->loop)
403 		ops->loop += gd->reloc_off
404 #endif
405 #endif
406 	/* Set the baud rate */
407 	if (ops->setbrg) {
408 		ret = ops->setbrg(dev, gd->baudrate);
409 		if (ret)
410 			return ret;
411 	}
412 
413 #ifdef CONFIG_DM_STDIO
414 	if (!(gd->flags & GD_FLG_RELOC))
415 		return 0;
416 	memset(&sdev, '\0', sizeof(sdev));
417 
418 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
419 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_DM;
420 	sdev.priv = dev;
421 	sdev.putc = serial_stub_putc;
422 	sdev.puts = serial_stub_puts;
423 	sdev.getc = serial_stub_getc;
424 	sdev.tstc = serial_stub_tstc;
425 
426 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
427 	/* Allocate the RX buffer */
428 	upriv->buf = malloc(CONFIG_SERIAL_RX_BUFFER_SIZE);
429 #endif
430 
431 	stdio_register_dev(&sdev, &upriv->sdev);
432 #endif
433 	return 0;
434 }
435 
436 static int serial_pre_remove(struct udevice *dev)
437 {
438 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
439 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
440 
441 	if (stdio_deregister_dev(upriv->sdev, true))
442 		return -EPERM;
443 #endif
444 
445 	return 0;
446 }
447 
448 UCLASS_DRIVER(serial) = {
449 	.id		= UCLASS_SERIAL,
450 	.name		= "serial",
451 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
452 	.post_probe	= serial_post_probe,
453 	.pre_remove	= serial_pre_remove,
454 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
455 };
456 #endif
457