summaryrefslogtreecommitdiff
path: root/lib/fdtdec.c
blob: 2149bd706849eaedffff039356482e31017faede (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
/*
 * Copyright (c) 2011 The Chromium OS Authors.
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <serial.h>
#include <libfdt.h>
#include <fdtdec.h>

/* we need the generic GPIO interface here */
#include <asm-generic/gpio.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * Here are the type we know about. One day we might allow drivers to
 * register. For now we just put them here. The COMPAT macro allows us to
 * turn this into a sparse list later, and keeps the ID with the name.
 */
#define COMPAT(id, name) name
static const char * const compat_names[COMPAT_COUNT] = {
	COMPAT(UNKNOWN, "<none>"),
	COMPAT(NVIDIA_TEGRA20_USB, "nvidia,tegra20-ehci"),
};

const char *fdtdec_get_compatible(enum fdt_compat_id id)
{
	/* We allow reading of the 'unknown' ID for testing purposes */
	assert(id >= 0 && id < COMPAT_COUNT);
	return compat_names[id];
}

/**
 * Look in the FDT for an alias with the given name and return its node.
 *
 * @param blob	FDT blob
 * @param name	alias name to look up
 * @return node offset if found, or an error code < 0 otherwise
 */
static int find_alias_node(const void *blob, const char *name)
{
	const char *path;
	int alias_node;

	debug("find_alias_node: %s\n", name);
	alias_node = fdt_path_offset(blob, "/aliases");
	if (alias_node < 0)
		return alias_node;
	path = fdt_getprop(blob, alias_node, name, NULL);
	if (!path)
		return -FDT_ERR_NOTFOUND;
	return fdt_path_offset(blob, path);
}

fdt_addr_t fdtdec_get_addr(const void *blob, int node,
		const char *prop_name)
{
	const fdt_addr_t *cell;
	int len;

	debug("get_addr: %s\n", prop_name);
	cell = fdt_getprop(blob, node, prop_name, &len);
	if (cell && (len == sizeof(fdt_addr_t) ||
			len == sizeof(fdt_addr_t) * 2))
		return fdt_addr_to_cpu(*cell);
	return FDT_ADDR_T_NONE;
}

s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
		s32 default_val)
{
	const s32 *cell;
	int len;

	debug("get_size: %s\n", prop_name);
	cell = fdt_getprop(blob, node, prop_name, &len);
	if (cell && len >= sizeof(s32))
		return fdt32_to_cpu(cell[0]);
	return default_val;
}

int fdtdec_get_is_enabled(const void *blob, int node)
{
	const char *cell;

	/*
	 * It should say "okay", so only allow that. Some fdts use "ok" but
	 * this is a bug. Please fix your device tree source file. See here
	 * for discussion:
	 *
	 * http://www.mail-archive.com/u-boot@lists.denx.de/msg71598.html
	 */
	cell = fdt_getprop(blob, node, "status", NULL);
	if (cell)
		return 0 == strcmp(cell, "okay");
	return 1;
}

enum fdt_compat_id fd_dec_lookup(const void *blob, int node)
{
	enum fdt_compat_id id;

	/* Search our drivers */
	for (id = COMPAT_UNKNOWN; id < COMPAT_COUNT; id++)
		if (0 == fdt_node_check_compatible(blob, node,
				compat_names[id]))
			return id;
	return COMPAT_UNKNOWN;
}

int fdtdec_next_compatible(const void *blob, int node,
		enum fdt_compat_id id)
{
	return fdt_node_offset_by_compatible(blob, node, compat_names[id]);
}

int fdtdec_next_alias(const void *blob, const char *name,
		enum fdt_compat_id id, int *upto)
{
#define MAX_STR_LEN 20
	char str[MAX_STR_LEN + 20];
	int node, err;

	/* snprintf() is not available */
	assert(strlen(name) < MAX_STR_LEN);
	sprintf(str, "%.*s%d", MAX_STR_LEN, name, *upto);
	node = find_alias_node(blob, str);
	if (node < 0)
		return node;
	err = fdt_node_check_compatible(blob, node, compat_names[id]);
	if (err < 0)
		return err;
	if (err)
		return -FDT_ERR_NOTFOUND;
	(*upto)++;
	return node;
}

int fdtdec_find_aliases_for_id(const void *blob, const char *name,
			enum fdt_compat_id id, int *node_list, int maxcount)
{
	memset(node_list, '\0', sizeof(*node_list) * maxcount);

	return fdtdec_add_aliases_for_id(blob, name, id, node_list, maxcount);
}

/* TODO: Can we tighten this code up a little? */
int fdtdec_add_aliases_for_id(const void *blob, const char *name,
			enum fdt_compat_id id, int *node_list, int maxcount)
{
	int name_len = strlen(name);
	int nodes[maxcount];
	int num_found = 0;
	int offset, node;
	int alias_node;
	int count;
	int i, j;

	/* find the alias node if present */
	alias_node = fdt_path_offset(blob, "/aliases");

	/*
	 * start with nothing, and we can assume that the root node can't
	 * match
	 */
	memset(nodes, '\0', sizeof(nodes));

	/* First find all the compatible nodes */
	for (node = count = 0; node >= 0 && count < maxcount;) {
		node = fdtdec_next_compatible(blob, node, id);
		if (node >= 0)
			nodes[count++] = node;
	}
	if (node >= 0)
		debug("%s: warning: maxcount exceeded with alias '%s'\n",
		       __func__, name);

	/* Now find all the aliases */
	for (offset = fdt_first_property_offset(blob, alias_node);
			offset > 0;
			offset = fdt_next_property_offset(blob, offset)) {
		const struct fdt_property *prop;
		const char *path;
		int number;
		int found;

		node = 0;
		prop = fdt_get_property_by_offset(blob, offset, NULL);
		path = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
		if (prop->len && 0 == strncmp(path, name, name_len))
			node = fdt_path_offset(blob, prop->data);
		if (node <= 0)
			continue;

		/* Get the alias number */
		number = simple_strtoul(path + name_len, NULL, 10);
		if (number < 0 || number >= maxcount) {
			debug("%s: warning: alias '%s' is out of range\n",
			       __func__, path);
			continue;
		}

		/* Make sure the node we found is actually in our list! */
		found = -1;
		for (j = 0; j < count; j++)
			if (nodes[j] == node) {
				found = j;
				break;
			}

		if (found == -1) {
			debug("%s: warning: alias '%s' points to a node "
				"'%s' that is missing or is not compatible "
				" with '%s'\n", __func__, path,
				fdt_get_name(blob, node, NULL),
			       compat_names[id]);
			continue;
		}

		/*
		 * Add this node to our list in the right place, and mark
		 * it as done.
		 */
		if (fdtdec_get_is_enabled(blob, node)) {
			if (node_list[number]) {
				debug("%s: warning: alias '%s' requires that "
				      "a node be placed in the list in a "
				      "position which is already filled by "
				      "node '%s'\n", __func__, path,
				      fdt_get_name(blob, node, NULL));
				continue;
			}
			node_list[number] = node;
			if (number >= num_found)
				num_found = number + 1;
		}
		nodes[found] = 0;
	}

	/* Add any nodes not mentioned by an alias */
	for (i = j = 0; i < maxcount; i++) {
		if (!node_list[i]) {
			for (; j < maxcount; j++)
				if (nodes[j] &&
					fdtdec_get_is_enabled(blob, nodes[j]))
					break;

			/* Have we run out of nodes to add? */
			if (j == maxcount)
				break;

			assert(!node_list[i]);
			node_list[i] = nodes[j++];
			if (i >= num_found)
				num_found = i + 1;
		}
	}

	return num_found;
}

int fdtdec_check_fdt(void)
{
	/*
	 * We must have an FDT, but we cannot panic() yet since the console
	 * is not ready. So for now, just assert(). Boards which need an early
	 * FDT (prior to console ready) will need to make their own
	 * arrangements and do their own checks.
	 */
	assert(!fdtdec_prepare_fdt());
	return 0;
}

/*
 * This function is a little odd in that it accesses global data. At some
 * point if the architecture board.c files merge this will make more sense.
 * Even now, it is common code.
 */
int fdtdec_prepare_fdt(void)
{
	if (((uintptr_t)gd->fdt_blob & 3) || fdt_check_header(gd->fdt_blob)) {
		printf("No valid FDT found - please append one to U-Boot "
			"binary, use u-boot-dtb.bin or define "
			"CONFIG_OF_EMBED\n");
		return -1;
	}
	return 0;
}

int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name)
{
	const u32 *phandle;
	int lookup;

	phandle = fdt_getprop(blob, node, prop_name, NULL);
	if (!phandle)
		return -FDT_ERR_NOTFOUND;

	lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
	return lookup;
}

/**
 * Look up a property in a node and check that it has a minimum length.
 *
 * @param blob		FDT blob
 * @param node		node to examine
 * @param prop_name	name of property to find
 * @param min_len	minimum property length in bytes
 * @param err		0 if ok, or -FDT_ERR_NOTFOUND if the property is not
			found, or -FDT_ERR_BADLAYOUT if not enough data
 * @return pointer to cell, which is only valid if err == 0
 */
static const void *get_prop_check_min_len(const void *blob, int node,
		const char *prop_name, int min_len, int *err)
{
	const void *cell;
	int len;

	debug("%s: %s\n", __func__, prop_name);
	cell = fdt_getprop(blob, node, prop_name, &len);
	if (!cell)
		*err = -FDT_ERR_NOTFOUND;
	else if (len < min_len)
		*err = -FDT_ERR_BADLAYOUT;
	else
		*err = 0;
	return cell;
}

int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
		u32 *array, int count)
{
	const u32 *cell;
	int i, err = 0;

	debug("%s: %s\n", __func__, prop_name);
	cell = get_prop_check_min_len(blob, node, prop_name,
				      sizeof(u32) * count, &err);
	if (!err) {
		for (i = 0; i < count; i++)
			array[i] = fdt32_to_cpu(cell[i]);
	}
	return err;
}

int fdtdec_get_bool(const void *blob, int node, const char *prop_name)
{
	const s32 *cell;
	int len;

	debug("%s: %s\n", __func__, prop_name);
	cell = fdt_getprop(blob, node, prop_name, &len);
	return cell != NULL;
}

/**
 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
 * terminating item.
 *
 * @param blob		FDT blob to use
 * @param node		Node to look at
 * @param prop_name	Node property name
 * @param gpio		Array of gpio elements to fill from FDT. This will be
 *			untouched if either 0 or an error is returned
 * @param max_count	Maximum number of elements allowed
 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
 */
static int fdtdec_decode_gpios(const void *blob, int node,
		const char *prop_name, struct fdt_gpio_state *gpio,
		int max_count)
{
	const struct fdt_property *prop;
	const u32 *cell;
	const char *name;
	int len, i;

	debug("%s: %s\n", __func__, prop_name);
	assert(max_count > 0);
	prop = fdt_get_property(blob, node, prop_name, &len);
	if (!prop) {
		debug("FDT: %s: property '%s' missing\n", __func__, prop_name);
		return -FDT_ERR_NOTFOUND;
	}

	/* We will use the name to tag the GPIO */
	name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
	cell = (u32 *)prop->data;
	len /= sizeof(u32) * 3;		/* 3 cells per GPIO record */
	if (len > max_count) {
		debug("FDT: %s: too many GPIOs / cells for "
			"property '%s'\n", __func__, prop_name);
		return -FDT_ERR_BADLAYOUT;
	}

	/* Read out the GPIO data from the cells */
	for (i = 0; i < len; i++, cell += 3) {
		gpio[i].gpio = fdt32_to_cpu(cell[1]);
		gpio[i].flags = fdt32_to_cpu(cell[2]);
		gpio[i].name = name;
	}

	return len;
}

int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
		struct fdt_gpio_state *gpio)
{
	int err;

	debug("%s: %s\n", __func__, prop_name);
	gpio->gpio = FDT_GPIO_NONE;
	gpio->name = NULL;
	err = fdtdec_decode_gpios(blob, node, prop_name, gpio, 1);
	return err == 1 ? 0 : err;
}

int fdtdec_setup_gpio(struct fdt_gpio_state *gpio)
{
	/*
	 * Return success if there is no GPIO defined. This is used for
	 * optional GPIOs)
	 */
	if (!fdt_gpio_isvalid(gpio))
		return 0;

	if (gpio_request(gpio->gpio, gpio->name))
		return -1;
	return 0;
}