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