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 <fdtdec.h>
12 #include <os.h>
13 #include <serial.h>
14 #include <stdio_dev.h>
15 #include <watchdog.h>
16 #include <dm/lists.h>
17 #include <dm/device-internal.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 void serial_find_console_or_panic(void)
31 {
32 	const void *blob = gd->fdt_blob;
33 	struct udevice *dev;
34 	int node;
35 
36 	if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
37 		uclass_first_device(UCLASS_SERIAL, &dev);
38 		if (dev) {
39 			gd->cur_serial_dev = dev;
40 			return;
41 		}
42 	} else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
43 		/* Check for a chosen console */
44 		node = fdtdec_get_chosen_node(blob, "stdout-path");
45 		if (node < 0) {
46 			const char *str, *p, *name;
47 
48 			/*
49 			 * Deal with things like
50 			 *	stdout-path = "serial0:115200n8";
51 			 *
52 			 * We need to look up the alias and then follow it to
53 			 * the correct node.
54 			 */
55 			str = fdtdec_get_chosen_prop(blob, "stdout-path");
56 			if (str) {
57 				p = strchr(str, ':');
58 				name = fdt_get_alias_namelen(blob, str,
59 						p ? p - str : strlen(str));
60 				if (name)
61 					node = fdt_path_offset(blob, name);
62 			}
63 		}
64 		if (node < 0)
65 			node = fdt_path_offset(blob, "console");
66 		if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node,
67 						    &dev)) {
68 			gd->cur_serial_dev = dev;
69 			return;
70 		}
71 
72 		/*
73 		 * If the console is not marked to be bound before relocation,
74 		 * bind it anyway.
75 		 */
76 		if (node > 0 &&
77 		    !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
78 				    &dev)) {
79 			if (!device_probe(dev)) {
80 				gd->cur_serial_dev = dev;
81 				return;
82 			}
83 		}
84 	}
85 	if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
86 		/*
87 		 * Try to use CONFIG_CONS_INDEX if available (it is numbered
88 		 * from 1!).
89 		 *
90 		 * Failing that, get the device with sequence number 0, or in
91 		 * extremis just the first serial device we can find. But we
92 		 * insist on having a console (even if it is silent).
93 		 */
94 #ifdef CONFIG_CONS_INDEX
95 #define INDEX (CONFIG_CONS_INDEX - 1)
96 #else
97 #define INDEX 0
98 #endif
99 		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
100 		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
101 		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
102 			gd->cur_serial_dev = dev;
103 			return;
104 		}
105 #undef INDEX
106 	}
107 
108 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
109 	panic_str("No serial driver found");
110 #endif
111 }
112 
113 /* Called prior to relocation */
114 int serial_init(void)
115 {
116 	serial_find_console_or_panic();
117 	gd->flags |= GD_FLG_SERIAL_READY;
118 
119 	return 0;
120 }
121 
122 /* Called after relocation */
123 void serial_initialize(void)
124 {
125 	serial_init();
126 }
127 
128 static void _serial_putc(struct udevice *dev, char ch)
129 {
130 	struct dm_serial_ops *ops = serial_get_ops(dev);
131 	int err;
132 
133 	if (ch == '\n')
134 		_serial_putc(dev, '\r');
135 
136 	do {
137 		err = ops->putc(dev, ch);
138 	} while (err == -EAGAIN);
139 }
140 
141 static void _serial_puts(struct udevice *dev, const char *str)
142 {
143 	while (*str)
144 		_serial_putc(dev, *str++);
145 }
146 
147 static int _serial_getc(struct udevice *dev)
148 {
149 	struct dm_serial_ops *ops = serial_get_ops(dev);
150 	int err;
151 
152 	do {
153 		err = ops->getc(dev);
154 		if (err == -EAGAIN)
155 			WATCHDOG_RESET();
156 	} while (err == -EAGAIN);
157 
158 	return err >= 0 ? err : 0;
159 }
160 
161 static int _serial_tstc(struct udevice *dev)
162 {
163 	struct dm_serial_ops *ops = serial_get_ops(dev);
164 
165 	if (ops->pending)
166 		return ops->pending(dev, true);
167 
168 	return 1;
169 }
170 
171 void serial_putc(char ch)
172 {
173 	if (gd->cur_serial_dev)
174 		_serial_putc(gd->cur_serial_dev, ch);
175 }
176 
177 void serial_puts(const char *str)
178 {
179 	if (gd->cur_serial_dev)
180 		_serial_puts(gd->cur_serial_dev, str);
181 }
182 
183 int serial_getc(void)
184 {
185 	if (!gd->cur_serial_dev)
186 		return 0;
187 
188 	return _serial_getc(gd->cur_serial_dev);
189 }
190 
191 int serial_tstc(void)
192 {
193 	if (!gd->cur_serial_dev)
194 		return 0;
195 
196 	return _serial_tstc(gd->cur_serial_dev);
197 }
198 
199 void serial_setbrg(void)
200 {
201 	struct dm_serial_ops *ops;
202 
203 	if (!gd->cur_serial_dev)
204 		return;
205 
206 	ops = serial_get_ops(gd->cur_serial_dev);
207 	if (ops->setbrg)
208 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
209 }
210 
211 void serial_stdio_init(void)
212 {
213 }
214 
215 #if defined(CONFIG_DM_STDIO) && CONFIG_IS_ENABLED(SERIAL_PRESENT)
216 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
217 {
218 	_serial_putc(sdev->priv, ch);
219 }
220 #endif
221 
222 void serial_stub_puts(struct stdio_dev *sdev, const char *str)
223 {
224 	_serial_puts(sdev->priv, str);
225 }
226 
227 int serial_stub_getc(struct stdio_dev *sdev)
228 {
229 	return _serial_getc(sdev->priv);
230 }
231 
232 int serial_stub_tstc(struct stdio_dev *sdev)
233 {
234 	return _serial_tstc(sdev->priv);
235 }
236 
237 /**
238  * on_baudrate() - Update the actual baudrate when the env var changes
239  *
240  * This will check for a valid baudrate and only apply it if valid.
241  */
242 static int on_baudrate(const char *name, const char *value, enum env_op op,
243 	int flags)
244 {
245 	int i;
246 	int baudrate;
247 
248 	switch (op) {
249 	case env_op_create:
250 	case env_op_overwrite:
251 		/*
252 		 * Switch to new baudrate if new baudrate is supported
253 		 */
254 		baudrate = simple_strtoul(value, NULL, 10);
255 
256 		/* Not actually changing */
257 		if (gd->baudrate == baudrate)
258 			return 0;
259 
260 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
261 			if (baudrate == baudrate_table[i])
262 				break;
263 		}
264 		if (i == ARRAY_SIZE(baudrate_table)) {
265 			if ((flags & H_FORCE) == 0)
266 				printf("## Baudrate %d bps not supported\n",
267 				       baudrate);
268 			return 1;
269 		}
270 		if ((flags & H_INTERACTIVE) != 0) {
271 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
272 			       baudrate);
273 			udelay(50000);
274 		}
275 
276 		gd->baudrate = baudrate;
277 
278 		serial_setbrg();
279 
280 		udelay(50000);
281 
282 		if ((flags & H_INTERACTIVE) != 0)
283 			while (1) {
284 				if (getc() == '\r')
285 					break;
286 			}
287 
288 		return 0;
289 	case env_op_delete:
290 		printf("## Baudrate may not be deleted\n");
291 		return 1;
292 	default:
293 		return 0;
294 	}
295 }
296 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
297 
298 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
299 static int serial_post_probe(struct udevice *dev)
300 {
301 	struct dm_serial_ops *ops = serial_get_ops(dev);
302 #ifdef CONFIG_DM_STDIO
303 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
304 	struct stdio_dev sdev;
305 #endif
306 	int ret;
307 
308 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
309 	if (ops->setbrg)
310 		ops->setbrg += gd->reloc_off;
311 	if (ops->getc)
312 		ops->getc += gd->reloc_off;
313 	if (ops->putc)
314 		ops->putc += gd->reloc_off;
315 	if (ops->pending)
316 		ops->pending += gd->reloc_off;
317 	if (ops->clear)
318 		ops->clear += gd->reloc_off;
319 #if CONFIG_POST & CONFIG_SYS_POST_UART
320 	if (ops->loop)
321 		ops->loop += gd->reloc_off
322 #endif
323 #endif
324 	/* Set the baud rate */
325 	if (ops->setbrg) {
326 		ret = ops->setbrg(dev, gd->baudrate);
327 		if (ret)
328 			return ret;
329 	}
330 
331 #ifdef CONFIG_DM_STDIO
332 	if (!(gd->flags & GD_FLG_RELOC))
333 		return 0;
334 	memset(&sdev, '\0', sizeof(sdev));
335 
336 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
337 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
338 	sdev.priv = dev;
339 	sdev.putc = serial_stub_putc;
340 	sdev.puts = serial_stub_puts;
341 	sdev.getc = serial_stub_getc;
342 	sdev.tstc = serial_stub_tstc;
343 	stdio_register_dev(&sdev, &upriv->sdev);
344 #endif
345 	return 0;
346 }
347 
348 static int serial_pre_remove(struct udevice *dev)
349 {
350 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
351 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
352 
353 	if (stdio_deregister_dev(upriv->sdev, true))
354 		return -EPERM;
355 #endif
356 
357 	return 0;
358 }
359 
360 UCLASS_DRIVER(serial) = {
361 	.id		= UCLASS_SERIAL,
362 	.name		= "serial",
363 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
364 	.post_probe	= serial_post_probe,
365 	.pre_remove	= serial_pre_remove,
366 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
367 };
368 #endif
369