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 #ifndef CONFIG_SYS_MALLOC_F_LEN
27 #error "Serial is required before relocation - define CONFIG_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 
78 	if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
79 		uclass_first_device(UCLASS_SERIAL, &dev);
80 		if (dev) {
81 			gd->cur_serial_dev = dev;
82 			return;
83 		}
84 	} else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
85 		/* Live tree has support for stdout */
86 		if (of_live_active()) {
87 			struct device_node *np = of_get_stdout();
88 
89 			if (np && !uclass_get_device_by_ofnode(UCLASS_SERIAL,
90 					np_to_ofnode(np), &dev)) {
91 				gd->cur_serial_dev = dev;
92 				return;
93 			}
94 		} else {
95 			if (!serial_check_stdout(blob, &dev)) {
96 				gd->cur_serial_dev = dev;
97 				return;
98 			}
99 		}
100 	}
101 	if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
102 		/*
103 		 * Try to use CONFIG_CONS_INDEX if available (it is numbered
104 		 * from 1!).
105 		 *
106 		 * Failing that, get the device with sequence number 0, or in
107 		 * extremis just the first serial device we can find. But we
108 		 * insist on having a console (even if it is silent).
109 		 */
110 #ifdef CONFIG_CONS_INDEX
111 #define INDEX (CONFIG_CONS_INDEX - 1)
112 #else
113 #define INDEX 0
114 #endif
115 		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
116 		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
117 		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
118 			gd->cur_serial_dev = dev;
119 			return;
120 		}
121 #undef INDEX
122 	}
123 
124 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
125 	panic_str("No serial driver found");
126 #endif
127 }
128 
129 /* Called prior to relocation */
130 int serial_init(void)
131 {
132 	serial_find_console_or_panic();
133 	gd->flags |= GD_FLG_SERIAL_READY;
134 
135 	return 0;
136 }
137 
138 /* Called after relocation */
139 void serial_initialize(void)
140 {
141 	serial_init();
142 }
143 
144 static void _serial_putc(struct udevice *dev, char ch)
145 {
146 	struct dm_serial_ops *ops = serial_get_ops(dev);
147 	int err;
148 
149 	if (ch == '\n')
150 		_serial_putc(dev, '\r');
151 
152 	do {
153 		err = ops->putc(dev, ch);
154 	} while (err == -EAGAIN);
155 }
156 
157 static void _serial_puts(struct udevice *dev, const char *str)
158 {
159 	while (*str)
160 		_serial_putc(dev, *str++);
161 }
162 
163 static int _serial_getc(struct udevice *dev)
164 {
165 	struct dm_serial_ops *ops = serial_get_ops(dev);
166 	int err;
167 
168 	do {
169 		err = ops->getc(dev);
170 		if (err == -EAGAIN)
171 			WATCHDOG_RESET();
172 	} while (err == -EAGAIN);
173 
174 	return err >= 0 ? err : 0;
175 }
176 
177 static int _serial_tstc(struct udevice *dev)
178 {
179 	struct dm_serial_ops *ops = serial_get_ops(dev);
180 
181 	if (ops->pending)
182 		return ops->pending(dev, true);
183 
184 	return 1;
185 }
186 
187 void serial_putc(char ch)
188 {
189 	if (gd->cur_serial_dev)
190 		_serial_putc(gd->cur_serial_dev, ch);
191 }
192 
193 void serial_puts(const char *str)
194 {
195 	if (gd->cur_serial_dev)
196 		_serial_puts(gd->cur_serial_dev, str);
197 }
198 
199 int serial_getc(void)
200 {
201 	if (!gd->cur_serial_dev)
202 		return 0;
203 
204 	return _serial_getc(gd->cur_serial_dev);
205 }
206 
207 int serial_tstc(void)
208 {
209 	if (!gd->cur_serial_dev)
210 		return 0;
211 
212 	return _serial_tstc(gd->cur_serial_dev);
213 }
214 
215 void serial_setbrg(void)
216 {
217 	struct dm_serial_ops *ops;
218 
219 	if (!gd->cur_serial_dev)
220 		return;
221 
222 	ops = serial_get_ops(gd->cur_serial_dev);
223 	if (ops->setbrg)
224 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
225 }
226 
227 void serial_stdio_init(void)
228 {
229 }
230 
231 #if defined(CONFIG_DM_STDIO)
232 
233 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
234 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
235 {
236 	_serial_putc(sdev->priv, ch);
237 }
238 #endif
239 
240 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
241 {
242 	_serial_puts(sdev->priv, str);
243 }
244 
245 static int serial_stub_getc(struct stdio_dev *sdev)
246 {
247 	return _serial_getc(sdev->priv);
248 }
249 
250 static int serial_stub_tstc(struct stdio_dev *sdev)
251 {
252 	return _serial_tstc(sdev->priv);
253 }
254 #endif
255 
256 /**
257  * on_baudrate() - Update the actual baudrate when the env var changes
258  *
259  * This will check for a valid baudrate and only apply it if valid.
260  */
261 static int on_baudrate(const char *name, const char *value, enum env_op op,
262 	int flags)
263 {
264 	int i;
265 	int baudrate;
266 
267 	switch (op) {
268 	case env_op_create:
269 	case env_op_overwrite:
270 		/*
271 		 * Switch to new baudrate if new baudrate is supported
272 		 */
273 		baudrate = simple_strtoul(value, NULL, 10);
274 
275 		/* Not actually changing */
276 		if (gd->baudrate == baudrate)
277 			return 0;
278 
279 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
280 			if (baudrate == baudrate_table[i])
281 				break;
282 		}
283 		if (i == ARRAY_SIZE(baudrate_table)) {
284 			if ((flags & H_FORCE) == 0)
285 				printf("## Baudrate %d bps not supported\n",
286 				       baudrate);
287 			return 1;
288 		}
289 		if ((flags & H_INTERACTIVE) != 0) {
290 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
291 			       baudrate);
292 			udelay(50000);
293 		}
294 
295 		gd->baudrate = baudrate;
296 
297 		serial_setbrg();
298 
299 		udelay(50000);
300 
301 		if ((flags & H_INTERACTIVE) != 0)
302 			while (1) {
303 				if (getc() == '\r')
304 					break;
305 			}
306 
307 		return 0;
308 	case env_op_delete:
309 		printf("## Baudrate may not be deleted\n");
310 		return 1;
311 	default:
312 		return 0;
313 	}
314 }
315 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
316 
317 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
318 static int serial_post_probe(struct udevice *dev)
319 {
320 	struct dm_serial_ops *ops = serial_get_ops(dev);
321 #ifdef CONFIG_DM_STDIO
322 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
323 	struct stdio_dev sdev;
324 #endif
325 	int ret;
326 
327 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
328 	if (ops->setbrg)
329 		ops->setbrg += gd->reloc_off;
330 	if (ops->getc)
331 		ops->getc += gd->reloc_off;
332 	if (ops->putc)
333 		ops->putc += gd->reloc_off;
334 	if (ops->pending)
335 		ops->pending += gd->reloc_off;
336 	if (ops->clear)
337 		ops->clear += gd->reloc_off;
338 #if CONFIG_POST & CONFIG_SYS_POST_UART
339 	if (ops->loop)
340 		ops->loop += gd->reloc_off
341 #endif
342 #endif
343 	/* Set the baud rate */
344 	if (ops->setbrg) {
345 		ret = ops->setbrg(dev, gd->baudrate);
346 		if (ret)
347 			return ret;
348 	}
349 
350 #ifdef CONFIG_DM_STDIO
351 	if (!(gd->flags & GD_FLG_RELOC))
352 		return 0;
353 	memset(&sdev, '\0', sizeof(sdev));
354 
355 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
356 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
357 	sdev.priv = dev;
358 	sdev.putc = serial_stub_putc;
359 	sdev.puts = serial_stub_puts;
360 	sdev.getc = serial_stub_getc;
361 	sdev.tstc = serial_stub_tstc;
362 	stdio_register_dev(&sdev, &upriv->sdev);
363 #endif
364 	return 0;
365 }
366 
367 static int serial_pre_remove(struct udevice *dev)
368 {
369 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
370 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
371 
372 	if (stdio_deregister_dev(upriv->sdev, true))
373 		return -EPERM;
374 #endif
375 
376 	return 0;
377 }
378 
379 UCLASS_DRIVER(serial) = {
380 	.id		= UCLASS_SERIAL,
381 	.name		= "serial",
382 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
383 	.post_probe	= serial_post_probe,
384 	.pre_remove	= serial_pre_remove,
385 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
386 };
387 #endif
388