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