1 /*
2  * Copyright (c) 2014 The Chromium OS Authors.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <environment.h>
10 #include <errno.h>
11 #include <os.h>
12 #include <serial.h>
13 #include <stdio_dev.h>
14 #include <watchdog.h>
15 #include <dm/lists.h>
16 #include <dm/device-internal.h>
17 #include <dm/of_access.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 /*
22  * Table with supported baudrates (defined in config_xyz.h)
23  */
24 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
25 
26 #if !CONFIG_VAL(SYS_MALLOC_F_LEN)
27 #error "Serial is required before relocation - define CONFIG_$(SPL_)SYS_MALLOC_F_LEN to make this work"
28 #endif
29 
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)) {
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 
155 /* Called prior to relocation */
156 int serial_init(void)
157 {
158 	serial_find_console_or_panic();
159 	gd->flags |= GD_FLG_SERIAL_READY;
160 
161 	return 0;
162 }
163 
164 /* Called after relocation */
165 void serial_initialize(void)
166 {
167 	serial_init();
168 }
169 
170 static void _serial_putc(struct udevice *dev, char ch)
171 {
172 	struct dm_serial_ops *ops = serial_get_ops(dev);
173 	int err;
174 
175 	if (ch == '\n')
176 		_serial_putc(dev, '\r');
177 
178 	do {
179 		err = ops->putc(dev, ch);
180 	} while (err == -EAGAIN);
181 }
182 
183 static void _serial_puts(struct udevice *dev, const char *str)
184 {
185 	while (*str)
186 		_serial_putc(dev, *str++);
187 }
188 
189 static int __serial_getc(struct udevice *dev)
190 {
191 	struct dm_serial_ops *ops = serial_get_ops(dev);
192 	int err;
193 
194 	do {
195 		err = ops->getc(dev);
196 		if (err == -EAGAIN)
197 			WATCHDOG_RESET();
198 	} while (err == -EAGAIN);
199 
200 	return err >= 0 ? err : 0;
201 }
202 
203 static int __serial_tstc(struct udevice *dev)
204 {
205 	struct dm_serial_ops *ops = serial_get_ops(dev);
206 
207 	if (ops->pending)
208 		return ops->pending(dev, true);
209 
210 	return 1;
211 }
212 
213 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
214 static int _serial_tstc(struct udevice *dev)
215 {
216 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
217 
218 	/* Read all available chars into the RX buffer */
219 	while (__serial_tstc(dev)) {
220 		upriv->buf[upriv->wr_ptr++] = __serial_getc(dev);
221 		upriv->wr_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
222 	}
223 
224 	return upriv->rd_ptr != upriv->wr_ptr ? 1 : 0;
225 }
226 
227 static int _serial_getc(struct udevice *dev)
228 {
229 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
230 	char val;
231 
232 	val = upriv->buf[upriv->rd_ptr++];
233 	upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
234 
235 	return val;
236 }
237 
238 #else /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
239 
240 static int _serial_getc(struct udevice *dev)
241 {
242 	return __serial_getc(dev);
243 }
244 
245 static int _serial_tstc(struct udevice *dev)
246 {
247 	return __serial_tstc(dev);
248 }
249 #endif /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
250 
251 void serial_putc(char ch)
252 {
253 	if (gd->cur_serial_dev)
254 		_serial_putc(gd->cur_serial_dev, ch);
255 }
256 
257 void serial_puts(const char *str)
258 {
259 	if (gd->cur_serial_dev)
260 		_serial_puts(gd->cur_serial_dev, str);
261 }
262 
263 int serial_getc(void)
264 {
265 	if (!gd->cur_serial_dev)
266 		return 0;
267 
268 	return _serial_getc(gd->cur_serial_dev);
269 }
270 
271 int serial_tstc(void)
272 {
273 	if (!gd->cur_serial_dev)
274 		return 0;
275 
276 	return _serial_tstc(gd->cur_serial_dev);
277 }
278 
279 void serial_setbrg(void)
280 {
281 	struct dm_serial_ops *ops;
282 
283 	if (!gd->cur_serial_dev)
284 		return;
285 
286 	ops = serial_get_ops(gd->cur_serial_dev);
287 	if (ops->setbrg)
288 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
289 }
290 
291 void serial_stdio_init(void)
292 {
293 }
294 
295 #if defined(CONFIG_DM_STDIO)
296 
297 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
298 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
299 {
300 	_serial_putc(sdev->priv, ch);
301 }
302 #endif
303 
304 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
305 {
306 	_serial_puts(sdev->priv, str);
307 }
308 
309 static int serial_stub_getc(struct stdio_dev *sdev)
310 {
311 	return _serial_getc(sdev->priv);
312 }
313 
314 static int serial_stub_tstc(struct stdio_dev *sdev)
315 {
316 	return _serial_tstc(sdev->priv);
317 }
318 #endif
319 
320 /**
321  * on_baudrate() - Update the actual baudrate when the env var changes
322  *
323  * This will check for a valid baudrate and only apply it if valid.
324  */
325 static int on_baudrate(const char *name, const char *value, enum env_op op,
326 	int flags)
327 {
328 	int i;
329 	int baudrate;
330 
331 	switch (op) {
332 	case env_op_create:
333 	case env_op_overwrite:
334 		/*
335 		 * Switch to new baudrate if new baudrate is supported
336 		 */
337 		baudrate = simple_strtoul(value, NULL, 10);
338 
339 		/* Not actually changing */
340 		if (gd->baudrate == baudrate)
341 			return 0;
342 
343 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
344 			if (baudrate == baudrate_table[i])
345 				break;
346 		}
347 		if (i == ARRAY_SIZE(baudrate_table)) {
348 			if ((flags & H_FORCE) == 0)
349 				printf("## Baudrate %d bps not supported\n",
350 				       baudrate);
351 			return 1;
352 		}
353 		if ((flags & H_INTERACTIVE) != 0) {
354 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
355 			       baudrate);
356 			udelay(50000);
357 		}
358 
359 		gd->baudrate = baudrate;
360 
361 		serial_setbrg();
362 
363 		udelay(50000);
364 
365 		if ((flags & H_INTERACTIVE) != 0)
366 			while (1) {
367 				if (getc() == '\r')
368 					break;
369 			}
370 
371 		return 0;
372 	case env_op_delete:
373 		printf("## Baudrate may not be deleted\n");
374 		return 1;
375 	default:
376 		return 0;
377 	}
378 }
379 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
380 
381 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
382 static int serial_post_probe(struct udevice *dev)
383 {
384 	struct dm_serial_ops *ops = serial_get_ops(dev);
385 #ifdef CONFIG_DM_STDIO
386 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
387 	struct stdio_dev sdev;
388 #endif
389 	int ret;
390 
391 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
392 	if (ops->setbrg)
393 		ops->setbrg += gd->reloc_off;
394 	if (ops->getc)
395 		ops->getc += gd->reloc_off;
396 	if (ops->putc)
397 		ops->putc += gd->reloc_off;
398 	if (ops->pending)
399 		ops->pending += gd->reloc_off;
400 	if (ops->clear)
401 		ops->clear += gd->reloc_off;
402 #if CONFIG_POST & CONFIG_SYS_POST_UART
403 	if (ops->loop)
404 		ops->loop += gd->reloc_off
405 #endif
406 #endif
407 	/* Set the baud rate */
408 	if (ops->setbrg) {
409 		ret = ops->setbrg(dev, gd->baudrate);
410 		if (ret)
411 			return ret;
412 	}
413 
414 #ifdef CONFIG_DM_STDIO
415 	if (!(gd->flags & GD_FLG_RELOC))
416 		return 0;
417 	memset(&sdev, '\0', sizeof(sdev));
418 
419 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
420 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_DM;
421 	sdev.priv = dev;
422 	sdev.putc = serial_stub_putc;
423 	sdev.puts = serial_stub_puts;
424 	sdev.getc = serial_stub_getc;
425 	sdev.tstc = serial_stub_tstc;
426 
427 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
428 	/* Allocate the RX buffer */
429 	upriv->buf = malloc(CONFIG_SERIAL_RX_BUFFER_SIZE);
430 #endif
431 
432 	stdio_register_dev(&sdev, &upriv->sdev);
433 #endif
434 	return 0;
435 }
436 
437 static int serial_pre_remove(struct udevice *dev)
438 {
439 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
440 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
441 
442 	if (stdio_deregister_dev(upriv->sdev, true))
443 		return -EPERM;
444 #endif
445 
446 	return 0;
447 }
448 
449 UCLASS_DRIVER(serial) = {
450 	.id		= UCLASS_SERIAL,
451 	.name		= "serial",
452 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
453 	.post_probe	= serial_post_probe,
454 	.pre_remove	= serial_pre_remove,
455 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
456 };
457 #endif
458