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 #include <ns16550.h>
20 
21 DECLARE_GLOBAL_DATA_PTR;
22 
23 /*
24  * Table with supported baudrates (defined in config_xyz.h)
25  */
26 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
27 
28 #ifndef CONFIG_SYS_MALLOC_F_LEN
29 #error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
30 #endif
31 
32 static void serial_find_console_or_panic(void)
33 {
34 	struct udevice *dev;
35 
36 #ifdef CONFIG_OF_CONTROL
37 	int node;
38 
39 	/* Check for a chosen console */
40 	node = fdtdec_get_chosen_node(gd->fdt_blob, "stdout-path");
41 	if (node < 0)
42 		node = fdt_path_offset(gd->fdt_blob, "console");
43 	if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, &dev)) {
44 		gd->cur_serial_dev = dev;
45 		return;
46 	}
47 
48 	/*
49 	 * If the console is not marked to be bound before relocation, bind
50 	 * it anyway.
51 	 */
52 	if (node > 0 &&
53 	    !lists_bind_fdt(gd->dm_root, gd->fdt_blob, node, &dev)) {
54 		if (!device_probe(dev)) {
55 			gd->cur_serial_dev = dev;
56 			return;
57 		}
58 	}
59 #endif
60 	/*
61 	 * Try to use CONFIG_CONS_INDEX if available (it is numbered from 1!).
62 	 *
63 	 * Failing that, get the device with sequence number 0, or in extremis
64 	 * just the first serial device we can find. But we insist on having
65 	 * 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 		panic("No serial driver found");
76 #undef INDEX
77 	gd->cur_serial_dev = dev;
78 }
79 
80 /* Called prior to relocation */
81 int serial_init(void)
82 {
83 	serial_find_console_or_panic();
84 	gd->flags |= GD_FLG_SERIAL_READY;
85 
86 	return 0;
87 }
88 
89 /* Called after relocation */
90 void serial_initialize(void)
91 {
92 	serial_find_console_or_panic();
93 }
94 
95 static void _serial_putc(struct udevice *dev, char ch)
96 {
97 	struct dm_serial_ops *ops = serial_get_ops(dev);
98 	int err;
99 
100 	do {
101 		err = ops->putc(dev, ch);
102 	} while (err == -EAGAIN);
103 	if (ch == '\n')
104 		_serial_putc(dev, '\r');
105 }
106 
107 static void _serial_puts(struct udevice *dev, const char *str)
108 {
109 	while (*str)
110 		_serial_putc(dev, *str++);
111 }
112 
113 static int _serial_getc(struct udevice *dev)
114 {
115 	struct dm_serial_ops *ops = serial_get_ops(dev);
116 	int err;
117 
118 	do {
119 		err = ops->getc(dev);
120 		if (err == -EAGAIN)
121 			WATCHDOG_RESET();
122 	} while (err == -EAGAIN);
123 
124 	return err >= 0 ? err : 0;
125 }
126 
127 static int _serial_tstc(struct udevice *dev)
128 {
129 	struct dm_serial_ops *ops = serial_get_ops(dev);
130 
131 	if (ops->pending)
132 		return ops->pending(dev, true);
133 
134 	return 1;
135 }
136 
137 void serial_putc(char ch)
138 {
139 	_serial_putc(gd->cur_serial_dev, ch);
140 }
141 
142 void serial_puts(const char *str)
143 {
144 	_serial_puts(gd->cur_serial_dev, str);
145 }
146 
147 int serial_getc(void)
148 {
149 	return _serial_getc(gd->cur_serial_dev);
150 }
151 
152 int serial_tstc(void)
153 {
154 	return _serial_tstc(gd->cur_serial_dev);
155 }
156 
157 void serial_setbrg(void)
158 {
159 	struct dm_serial_ops *ops = serial_get_ops(gd->cur_serial_dev);
160 
161 	if (ops->setbrg)
162 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
163 }
164 
165 void serial_stdio_init(void)
166 {
167 }
168 
169 #ifdef CONFIG_DM_STDIO
170 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
171 {
172 	_serial_putc(sdev->priv, ch);
173 }
174 #endif
175 
176 void serial_stub_puts(struct stdio_dev *sdev, const char *str)
177 {
178 	_serial_puts(sdev->priv, str);
179 }
180 
181 int serial_stub_getc(struct stdio_dev *sdev)
182 {
183 	return _serial_getc(sdev->priv);
184 }
185 
186 int serial_stub_tstc(struct stdio_dev *sdev)
187 {
188 	return _serial_tstc(sdev->priv);
189 }
190 
191 /**
192  * on_baudrate() - Update the actual baudrate when the env var changes
193  *
194  * This will check for a valid baudrate and only apply it if valid.
195  */
196 static int on_baudrate(const char *name, const char *value, enum env_op op,
197 	int flags)
198 {
199 	int i;
200 	int baudrate;
201 
202 	switch (op) {
203 	case env_op_create:
204 	case env_op_overwrite:
205 		/*
206 		 * Switch to new baudrate if new baudrate is supported
207 		 */
208 		baudrate = simple_strtoul(value, NULL, 10);
209 
210 		/* Not actually changing */
211 		if (gd->baudrate == baudrate)
212 			return 0;
213 
214 		for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
215 			if (baudrate == baudrate_table[i])
216 				break;
217 		}
218 		if (i == ARRAY_SIZE(baudrate_table)) {
219 			if ((flags & H_FORCE) == 0)
220 				printf("## Baudrate %d bps not supported\n",
221 				       baudrate);
222 			return 1;
223 		}
224 		if ((flags & H_INTERACTIVE) != 0) {
225 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
226 			       baudrate);
227 			udelay(50000);
228 		}
229 
230 		gd->baudrate = baudrate;
231 
232 		serial_setbrg();
233 
234 		udelay(50000);
235 
236 		if ((flags & H_INTERACTIVE) != 0)
237 			while (1) {
238 				if (getc() == '\r')
239 					break;
240 			}
241 
242 		return 0;
243 	case env_op_delete:
244 		printf("## Baudrate may not be deleted\n");
245 		return 1;
246 	default:
247 		return 0;
248 	}
249 }
250 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
251 
252 static int serial_post_probe(struct udevice *dev)
253 {
254 	struct dm_serial_ops *ops = serial_get_ops(dev);
255 #ifdef CONFIG_DM_STDIO
256 	struct serial_dev_priv *upriv = dev->uclass_priv;
257 	struct stdio_dev sdev;
258 #endif
259 	int ret;
260 
261 	/* Set the baud rate */
262 	if (ops->setbrg) {
263 		ret = ops->setbrg(dev, gd->baudrate);
264 		if (ret)
265 			return ret;
266 	}
267 
268 #ifdef CONFIG_DM_STDIO
269 	if (!(gd->flags & GD_FLG_RELOC))
270 		return 0;
271 	memset(&sdev, '\0', sizeof(sdev));
272 
273 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
274 	sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
275 	sdev.priv = dev;
276 	sdev.putc = serial_stub_putc;
277 	sdev.puts = serial_stub_puts;
278 	sdev.getc = serial_stub_getc;
279 	sdev.tstc = serial_stub_tstc;
280 	stdio_register_dev(&sdev, &upriv->sdev);
281 #endif
282 	return 0;
283 }
284 
285 static int serial_pre_remove(struct udevice *dev)
286 {
287 #ifdef CONFIG_SYS_STDIO_DEREGISTER
288 	struct serial_dev_priv *upriv = dev->uclass_priv;
289 
290 	if (stdio_deregister_dev(upriv->sdev, 0))
291 		return -EPERM;
292 #endif
293 
294 	return 0;
295 }
296 
297 UCLASS_DRIVER(serial) = {
298 	.id		= UCLASS_SERIAL,
299 	.name		= "serial",
300 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
301 	.post_probe	= serial_post_probe,
302 	.pre_remove	= serial_pre_remove,
303 	.per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
304 };
305