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