uart_subr.c revision 303975 
1/*-
2 * Copyright (c) 2004 Marcel Moolenaar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: releng/11.0/sys/dev/uart/uart_subr.c 298411 2016-04-21 15:38:28Z pfg $");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/bus.h>
33
34#include <machine/bus.h>
35#include <machine/vmparam.h>
36
37#include <dev/uart/uart.h>
38#include <dev/uart/uart_cpu.h>
39
40#define	UART_TAG_BR	0
41#define	UART_TAG_CH	1
42#define	UART_TAG_DB	2
43#define	UART_TAG_DT	3
44#define	UART_TAG_IO	4
45#define	UART_TAG_MM	5
46#define	UART_TAG_PA	6
47#define	UART_TAG_RS	7
48#define	UART_TAG_SB	8
49#define	UART_TAG_XO	9
50
51static struct uart_class *uart_classes[] = {
52	&uart_ns8250_class,
53	&uart_sab82532_class,
54	&uart_z8530_class,
55#if defined(__arm__)
56	&uart_s3c2410_class,
57#endif
58};
59
60static bus_addr_t
61uart_parse_addr(const char **p)
62{
63	return (strtoul(*p, (char**)(uintptr_t)p, 0));
64}
65
66static struct uart_class *
67uart_parse_class(struct uart_class *class, const char **p)
68{
69	struct uart_class *uc;
70	const char *nm;
71	size_t len;
72	u_int i;
73
74	for (i = 0; i < nitems(uart_classes); i++) {
75		uc = uart_classes[i];
76		nm = uart_getname(uc);
77		if (nm == NULL || *nm == '\0')
78			continue;
79		len = strlen(nm);
80		if (strncmp(nm, *p, len) == 0) {
81			*p += len;
82			return (uc);
83		}
84	}
85	return (class);
86}
87
88static long
89uart_parse_long(const char **p)
90{
91	return (strtol(*p, (char**)(uintptr_t)p, 0));
92}
93
94static int
95uart_parse_parity(const char **p)
96{
97	if (!strncmp(*p, "even", 4)) {
98		*p += 4;
99		return UART_PARITY_EVEN;
100	}
101	if (!strncmp(*p, "mark", 4)) {
102		*p += 4;
103		return UART_PARITY_MARK;
104	}
105	if (!strncmp(*p, "none", 4)) {
106		*p += 4;
107		return UART_PARITY_NONE;
108	}
109	if (!strncmp(*p, "odd", 3)) {
110		*p += 3;
111		return UART_PARITY_ODD;
112	}
113	if (!strncmp(*p, "space", 5)) {
114		*p += 5;
115		return UART_PARITY_SPACE;
116	}
117	return (-1);
118}
119
120static int
121uart_parse_tag(const char **p)
122{
123	int tag;
124
125	if ((*p)[0] == 'b' && (*p)[1] == 'r') {
126		tag = UART_TAG_BR;
127		goto out;
128	}
129	if ((*p)[0] == 'c' && (*p)[1] == 'h') {
130		tag = UART_TAG_CH;
131		goto out;
132	}
133	if ((*p)[0] == 'd' && (*p)[1] == 'b') {
134		tag = UART_TAG_DB;
135		goto out;
136	}
137	if ((*p)[0] == 'd' && (*p)[1] == 't') {
138		tag = UART_TAG_DT;
139		goto out;
140	}
141	if ((*p)[0] == 'i' && (*p)[1] == 'o') {
142		tag = UART_TAG_IO;
143		goto out;
144	}
145	if ((*p)[0] == 'm' && (*p)[1] == 'm') {
146		tag = UART_TAG_MM;
147		goto out;
148	}
149	if ((*p)[0] == 'p' && (*p)[1] == 'a') {
150		tag = UART_TAG_PA;
151		goto out;
152	}
153	if ((*p)[0] == 'r' && (*p)[1] == 's') {
154		tag = UART_TAG_RS;
155		goto out;
156	}
157	if ((*p)[0] == 's' && (*p)[1] == 'b') {
158		tag = UART_TAG_SB;
159		goto out;
160	}
161	if ((*p)[0] == 'x' && (*p)[1] == 'o') {
162		tag = UART_TAG_XO;
163		goto out;
164	}
165	return (-1);
166
167out:
168	*p += 2;
169	if ((*p)[0] != ':')
170		return (-1);
171	(*p)++;
172	return (tag);
173}
174
175/*
176 * Parse a device specification. The specification is a list of attributes
177 * separated by commas. Each attribute is a tag-value pair with the tag and
178 * value separated by a colon. Supported tags are:
179 *
180 *	br = Baudrate
181 *	ch = Channel
182 *	db = Data bits
183 *	dt = Device type
184 *	io = I/O port address
185 *	mm = Memory mapped I/O address
186 *	pa = Parity
187 *	rs = Register shift
188 *	sb = Stopbits
189 *	xo = Device clock (xtal oscillator)
190 *
191 * The io and mm tags are mutually exclusive.
192 */
193
194int
195uart_getenv(int devtype, struct uart_devinfo *di, struct uart_class *class)
196{
197	const char *spec;
198	char *cp;
199	bus_addr_t addr = ~0U;
200	int error;
201
202	/*
203	 * All uart_class references are weak. Make sure the default
204	 * device class has been compiled-in.
205	 */
206	if (class == NULL)
207		return (ENXIO);
208
209	/*
210	 * Check the environment variables "hw.uart.console" and
211	 * "hw.uart.dbgport". These variables, when present, specify
212	 * which UART port is to be used as serial console or debug
213	 * port (resp).
214	 */
215	switch (devtype) {
216	case UART_DEV_CONSOLE:
217		cp = kern_getenv("hw.uart.console");
218		break;
219	case UART_DEV_DBGPORT:
220		cp = kern_getenv("hw.uart.dbgport");
221		break;
222	default:
223		cp = NULL;
224		break;
225	}
226
227	if (cp == NULL)
228		return (ENXIO);
229
230	/* Set defaults. */
231	di->bas.chan = 0;
232	di->bas.regshft = 0;
233	di->bas.rclk = 0;
234	di->baudrate = 0;
235	di->databits = 8;
236	di->stopbits = 1;
237	di->parity = UART_PARITY_NONE;
238
239	/* Parse the attributes. */
240	spec = cp;
241	for (;;) {
242		switch (uart_parse_tag(&spec)) {
243		case UART_TAG_BR:
244			di->baudrate = uart_parse_long(&spec);
245			break;
246		case UART_TAG_CH:
247			di->bas.chan = uart_parse_long(&spec);
248			break;
249		case UART_TAG_DB:
250			di->databits = uart_parse_long(&spec);
251			break;
252		case UART_TAG_DT:
253			class = uart_parse_class(class, &spec);
254			break;
255		case UART_TAG_IO:
256			di->bas.bst = uart_bus_space_io;
257			addr = uart_parse_addr(&spec);
258			break;
259		case UART_TAG_MM:
260			di->bas.bst = uart_bus_space_mem;
261			addr = uart_parse_addr(&spec);
262			break;
263		case UART_TAG_PA:
264			di->parity = uart_parse_parity(&spec);
265			break;
266		case UART_TAG_RS:
267			di->bas.regshft = uart_parse_long(&spec);
268			break;
269		case UART_TAG_SB:
270			di->stopbits = uart_parse_long(&spec);
271			break;
272		case UART_TAG_XO:
273			di->bas.rclk = uart_parse_long(&spec);
274			break;
275		default:
276			freeenv(cp);
277			return (EINVAL);
278		}
279		if (*spec == '\0')
280			break;
281		if (*spec != ',') {
282			freeenv(cp);
283			return (EINVAL);
284		}
285		spec++;
286	}
287	freeenv(cp);
288
289	/*
290	 * If we still have an invalid address, the specification must be
291	 * missing an I/O port or memory address. We don't like that.
292	 */
293	if (addr == ~0U)
294		return (EINVAL);
295
296	/*
297	 * Accept only the well-known baudrates. Any invalid baudrate
298	 * is silently replaced with a 0-valued baudrate. The 0 baudrate
299	 * has special meaning. It means that we're not supposed to
300	 * program the baudrate and simply communicate with whatever
301	 * speed the hardware is currently programmed for.
302	 */
303	if (di->baudrate >= 19200) {
304		if (di->baudrate % 19200)
305			di->baudrate = 0;
306	} else if (di->baudrate >= 1200) {
307		if (di->baudrate % 1200)
308			di->baudrate = 0;
309	} else if (di->baudrate > 0) {
310		if (di->baudrate % 75)
311			di->baudrate = 0;
312	} else
313		di->baudrate = 0;
314
315	/* Set the ops and create a bus space handle. */
316	di->ops = uart_getops(class);
317	error = bus_space_map(di->bas.bst, addr, uart_getrange(class), 0,
318	    &di->bas.bsh);
319	return (error);
320}
321