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