xref: /openbmc/u-boot/lib/fdtdec.c (revision a2ac1b3a)
1 /*
2  * Copyright (c) 2011 The Chromium OS Authors.
3  * See file CREDITS for list of people who contributed to this
4  * project.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of
9  * the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
19  * MA 02111-1307 USA
20  */
21 
22 #include <common.h>
23 #include <serial.h>
24 #include <libfdt.h>
25 #include <fdtdec.h>
26 
27 #include <asm/gpio.h>
28 
29 DECLARE_GLOBAL_DATA_PTR;
30 
31 /*
32  * Here are the type we know about. One day we might allow drivers to
33  * register. For now we just put them here. The COMPAT macro allows us to
34  * turn this into a sparse list later, and keeps the ID with the name.
35  */
36 #define COMPAT(id, name) name
37 static const char * const compat_names[COMPAT_COUNT] = {
38 	COMPAT(UNKNOWN, "<none>"),
39 	COMPAT(NVIDIA_TEGRA20_USB, "nvidia,tegra20-ehci"),
40 	COMPAT(NVIDIA_TEGRA20_I2C, "nvidia,tegra20-i2c"),
41 	COMPAT(NVIDIA_TEGRA20_DVC, "nvidia,tegra20-i2c-dvc"),
42 	COMPAT(NVIDIA_TEGRA20_EMC, "nvidia,tegra20-emc"),
43 	COMPAT(NVIDIA_TEGRA20_EMC_TABLE, "nvidia,tegra20-emc-table"),
44 	COMPAT(NVIDIA_TEGRA20_KBC, "nvidia,tegra20-kbc"),
45 	COMPAT(NVIDIA_TEGRA20_NAND, "nvidia,tegra20-nand"),
46 };
47 
48 const char *fdtdec_get_compatible(enum fdt_compat_id id)
49 {
50 	/* We allow reading of the 'unknown' ID for testing purposes */
51 	assert(id >= 0 && id < COMPAT_COUNT);
52 	return compat_names[id];
53 }
54 
55 /**
56  * Look in the FDT for an alias with the given name and return its node.
57  *
58  * @param blob	FDT blob
59  * @param name	alias name to look up
60  * @return node offset if found, or an error code < 0 otherwise
61  */
62 static int find_alias_node(const void *blob, const char *name)
63 {
64 	const char *path;
65 	int alias_node;
66 
67 	debug("find_alias_node: %s\n", name);
68 	alias_node = fdt_path_offset(blob, "/aliases");
69 	if (alias_node < 0)
70 		return alias_node;
71 	path = fdt_getprop(blob, alias_node, name, NULL);
72 	if (!path)
73 		return -FDT_ERR_NOTFOUND;
74 	return fdt_path_offset(blob, path);
75 }
76 
77 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
78 		const char *prop_name)
79 {
80 	const fdt_addr_t *cell;
81 	int len;
82 
83 	debug("%s: %s: ", __func__, prop_name);
84 	cell = fdt_getprop(blob, node, prop_name, &len);
85 	if (cell && (len == sizeof(fdt_addr_t) ||
86 			len == sizeof(fdt_addr_t) * 2)) {
87 		fdt_addr_t addr = fdt_addr_to_cpu(*cell);
88 
89 		debug("%p\n", (void *)addr);
90 		return addr;
91 	}
92 	debug("(not found)\n");
93 	return FDT_ADDR_T_NONE;
94 }
95 
96 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
97 		s32 default_val)
98 {
99 	const s32 *cell;
100 	int len;
101 
102 	debug("%s: %s: ", __func__, prop_name);
103 	cell = fdt_getprop(blob, node, prop_name, &len);
104 	if (cell && len >= sizeof(s32)) {
105 		s32 val = fdt32_to_cpu(cell[0]);
106 
107 		debug("%#x (%d)\n", val, val);
108 		return val;
109 	}
110 	debug("(not found)\n");
111 	return default_val;
112 }
113 
114 int fdtdec_get_is_enabled(const void *blob, int node)
115 {
116 	const char *cell;
117 
118 	/*
119 	 * It should say "okay", so only allow that. Some fdts use "ok" but
120 	 * this is a bug. Please fix your device tree source file. See here
121 	 * for discussion:
122 	 *
123 	 * http://www.mail-archive.com/u-boot@lists.denx.de/msg71598.html
124 	 */
125 	cell = fdt_getprop(blob, node, "status", NULL);
126 	if (cell)
127 		return 0 == strcmp(cell, "okay");
128 	return 1;
129 }
130 
131 enum fdt_compat_id fd_dec_lookup(const void *blob, int node)
132 {
133 	enum fdt_compat_id id;
134 
135 	/* Search our drivers */
136 	for (id = COMPAT_UNKNOWN; id < COMPAT_COUNT; id++)
137 		if (0 == fdt_node_check_compatible(blob, node,
138 				compat_names[id]))
139 			return id;
140 	return COMPAT_UNKNOWN;
141 }
142 
143 int fdtdec_next_compatible(const void *blob, int node,
144 		enum fdt_compat_id id)
145 {
146 	return fdt_node_offset_by_compatible(blob, node, compat_names[id]);
147 }
148 
149 int fdtdec_next_compatible_subnode(const void *blob, int node,
150 		enum fdt_compat_id id, int *depthp)
151 {
152 	do {
153 		node = fdt_next_node(blob, node, depthp);
154 	} while (*depthp > 1);
155 
156 	/* If this is a direct subnode, and compatible, return it */
157 	if (*depthp == 1 && 0 == fdt_node_check_compatible(
158 						blob, node, compat_names[id]))
159 		return node;
160 
161 	return -FDT_ERR_NOTFOUND;
162 }
163 
164 int fdtdec_next_alias(const void *blob, const char *name,
165 		enum fdt_compat_id id, int *upto)
166 {
167 #define MAX_STR_LEN 20
168 	char str[MAX_STR_LEN + 20];
169 	int node, err;
170 
171 	/* snprintf() is not available */
172 	assert(strlen(name) < MAX_STR_LEN);
173 	sprintf(str, "%.*s%d", MAX_STR_LEN, name, *upto);
174 	node = find_alias_node(blob, str);
175 	if (node < 0)
176 		return node;
177 	err = fdt_node_check_compatible(blob, node, compat_names[id]);
178 	if (err < 0)
179 		return err;
180 	if (err)
181 		return -FDT_ERR_NOTFOUND;
182 	(*upto)++;
183 	return node;
184 }
185 
186 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
187 			enum fdt_compat_id id, int *node_list, int maxcount)
188 {
189 	memset(node_list, '\0', sizeof(*node_list) * maxcount);
190 
191 	return fdtdec_add_aliases_for_id(blob, name, id, node_list, maxcount);
192 }
193 
194 /* TODO: Can we tighten this code up a little? */
195 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
196 			enum fdt_compat_id id, int *node_list, int maxcount)
197 {
198 	int name_len = strlen(name);
199 	int nodes[maxcount];
200 	int num_found = 0;
201 	int offset, node;
202 	int alias_node;
203 	int count;
204 	int i, j;
205 
206 	/* find the alias node if present */
207 	alias_node = fdt_path_offset(blob, "/aliases");
208 
209 	/*
210 	 * start with nothing, and we can assume that the root node can't
211 	 * match
212 	 */
213 	memset(nodes, '\0', sizeof(nodes));
214 
215 	/* First find all the compatible nodes */
216 	for (node = count = 0; node >= 0 && count < maxcount;) {
217 		node = fdtdec_next_compatible(blob, node, id);
218 		if (node >= 0)
219 			nodes[count++] = node;
220 	}
221 	if (node >= 0)
222 		debug("%s: warning: maxcount exceeded with alias '%s'\n",
223 		       __func__, name);
224 
225 	/* Now find all the aliases */
226 	for (offset = fdt_first_property_offset(blob, alias_node);
227 			offset > 0;
228 			offset = fdt_next_property_offset(blob, offset)) {
229 		const struct fdt_property *prop;
230 		const char *path;
231 		int number;
232 		int found;
233 
234 		node = 0;
235 		prop = fdt_get_property_by_offset(blob, offset, NULL);
236 		path = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
237 		if (prop->len && 0 == strncmp(path, name, name_len))
238 			node = fdt_path_offset(blob, prop->data);
239 		if (node <= 0)
240 			continue;
241 
242 		/* Get the alias number */
243 		number = simple_strtoul(path + name_len, NULL, 10);
244 		if (number < 0 || number >= maxcount) {
245 			debug("%s: warning: alias '%s' is out of range\n",
246 			       __func__, path);
247 			continue;
248 		}
249 
250 		/* Make sure the node we found is actually in our list! */
251 		found = -1;
252 		for (j = 0; j < count; j++)
253 			if (nodes[j] == node) {
254 				found = j;
255 				break;
256 			}
257 
258 		if (found == -1) {
259 			debug("%s: warning: alias '%s' points to a node "
260 				"'%s' that is missing or is not compatible "
261 				" with '%s'\n", __func__, path,
262 				fdt_get_name(blob, node, NULL),
263 			       compat_names[id]);
264 			continue;
265 		}
266 
267 		/*
268 		 * Add this node to our list in the right place, and mark
269 		 * it as done.
270 		 */
271 		if (fdtdec_get_is_enabled(blob, node)) {
272 			if (node_list[number]) {
273 				debug("%s: warning: alias '%s' requires that "
274 				      "a node be placed in the list in a "
275 				      "position which is already filled by "
276 				      "node '%s'\n", __func__, path,
277 				      fdt_get_name(blob, node, NULL));
278 				continue;
279 			}
280 			node_list[number] = node;
281 			if (number >= num_found)
282 				num_found = number + 1;
283 		}
284 		nodes[found] = 0;
285 	}
286 
287 	/* Add any nodes not mentioned by an alias */
288 	for (i = j = 0; i < maxcount; i++) {
289 		if (!node_list[i]) {
290 			for (; j < maxcount; j++)
291 				if (nodes[j] &&
292 					fdtdec_get_is_enabled(blob, nodes[j]))
293 					break;
294 
295 			/* Have we run out of nodes to add? */
296 			if (j == maxcount)
297 				break;
298 
299 			assert(!node_list[i]);
300 			node_list[i] = nodes[j++];
301 			if (i >= num_found)
302 				num_found = i + 1;
303 		}
304 	}
305 
306 	return num_found;
307 }
308 
309 int fdtdec_check_fdt(void)
310 {
311 	/*
312 	 * We must have an FDT, but we cannot panic() yet since the console
313 	 * is not ready. So for now, just assert(). Boards which need an early
314 	 * FDT (prior to console ready) will need to make their own
315 	 * arrangements and do their own checks.
316 	 */
317 	assert(!fdtdec_prepare_fdt());
318 	return 0;
319 }
320 
321 /*
322  * This function is a little odd in that it accesses global data. At some
323  * point if the architecture board.c files merge this will make more sense.
324  * Even now, it is common code.
325  */
326 int fdtdec_prepare_fdt(void)
327 {
328 	if (((uintptr_t)gd->fdt_blob & 3) || fdt_check_header(gd->fdt_blob)) {
329 		printf("No valid FDT found - please append one to U-Boot "
330 			"binary, use u-boot-dtb.bin or define "
331 			"CONFIG_OF_EMBED\n");
332 		return -1;
333 	}
334 	return 0;
335 }
336 
337 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name)
338 {
339 	const u32 *phandle;
340 	int lookup;
341 
342 	debug("%s: %s\n", __func__, prop_name);
343 	phandle = fdt_getprop(blob, node, prop_name, NULL);
344 	if (!phandle)
345 		return -FDT_ERR_NOTFOUND;
346 
347 	lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
348 	return lookup;
349 }
350 
351 /**
352  * Look up a property in a node and check that it has a minimum length.
353  *
354  * @param blob		FDT blob
355  * @param node		node to examine
356  * @param prop_name	name of property to find
357  * @param min_len	minimum property length in bytes
358  * @param err		0 if ok, or -FDT_ERR_NOTFOUND if the property is not
359 			found, or -FDT_ERR_BADLAYOUT if not enough data
360  * @return pointer to cell, which is only valid if err == 0
361  */
362 static const void *get_prop_check_min_len(const void *blob, int node,
363 		const char *prop_name, int min_len, int *err)
364 {
365 	const void *cell;
366 	int len;
367 
368 	debug("%s: %s\n", __func__, prop_name);
369 	cell = fdt_getprop(blob, node, prop_name, &len);
370 	if (!cell)
371 		*err = -FDT_ERR_NOTFOUND;
372 	else if (len < min_len)
373 		*err = -FDT_ERR_BADLAYOUT;
374 	else
375 		*err = 0;
376 	return cell;
377 }
378 
379 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
380 		u32 *array, int count)
381 {
382 	const u32 *cell;
383 	int i, err = 0;
384 
385 	debug("%s: %s\n", __func__, prop_name);
386 	cell = get_prop_check_min_len(blob, node, prop_name,
387 				      sizeof(u32) * count, &err);
388 	if (!err) {
389 		for (i = 0; i < count; i++)
390 			array[i] = fdt32_to_cpu(cell[i]);
391 	}
392 	return err;
393 }
394 
395 const u32 *fdtdec_locate_array(const void *blob, int node,
396 			       const char *prop_name, int count)
397 {
398 	const u32 *cell;
399 	int err;
400 
401 	cell = get_prop_check_min_len(blob, node, prop_name,
402 				      sizeof(u32) * count, &err);
403 	return err ? NULL : cell;
404 }
405 
406 int fdtdec_get_bool(const void *blob, int node, const char *prop_name)
407 {
408 	const s32 *cell;
409 	int len;
410 
411 	debug("%s: %s\n", __func__, prop_name);
412 	cell = fdt_getprop(blob, node, prop_name, &len);
413 	return cell != NULL;
414 }
415 
416 /**
417  * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
418  * terminating item.
419  *
420  * @param blob		FDT blob to use
421  * @param node		Node to look at
422  * @param prop_name	Node property name
423  * @param gpio		Array of gpio elements to fill from FDT. This will be
424  *			untouched if either 0 or an error is returned
425  * @param max_count	Maximum number of elements allowed
426  * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
427  * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
428  */
429 static int fdtdec_decode_gpios(const void *blob, int node,
430 		const char *prop_name, struct fdt_gpio_state *gpio,
431 		int max_count)
432 {
433 	const struct fdt_property *prop;
434 	const u32 *cell;
435 	const char *name;
436 	int len, i;
437 
438 	debug("%s: %s\n", __func__, prop_name);
439 	assert(max_count > 0);
440 	prop = fdt_get_property(blob, node, prop_name, &len);
441 	if (!prop) {
442 		debug("%s: property '%s' missing\n", __func__, prop_name);
443 		return -FDT_ERR_NOTFOUND;
444 	}
445 
446 	/* We will use the name to tag the GPIO */
447 	name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
448 	cell = (u32 *)prop->data;
449 	len /= sizeof(u32) * 3;		/* 3 cells per GPIO record */
450 	if (len > max_count) {
451 		debug(" %s: too many GPIOs / cells for "
452 			"property '%s'\n", __func__, prop_name);
453 		return -FDT_ERR_BADLAYOUT;
454 	}
455 
456 	/* Read out the GPIO data from the cells */
457 	for (i = 0; i < len; i++, cell += 3) {
458 		gpio[i].gpio = fdt32_to_cpu(cell[1]);
459 		gpio[i].flags = fdt32_to_cpu(cell[2]);
460 		gpio[i].name = name;
461 	}
462 
463 	return len;
464 }
465 
466 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
467 		struct fdt_gpio_state *gpio)
468 {
469 	int err;
470 
471 	debug("%s: %s\n", __func__, prop_name);
472 	gpio->gpio = FDT_GPIO_NONE;
473 	gpio->name = NULL;
474 	err = fdtdec_decode_gpios(blob, node, prop_name, gpio, 1);
475 	return err == 1 ? 0 : err;
476 }
477 
478 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio)
479 {
480 	/*
481 	 * Return success if there is no GPIO defined. This is used for
482 	 * optional GPIOs)
483 	 */
484 	if (!fdt_gpio_isvalid(gpio))
485 		return 0;
486 
487 	if (gpio_request(gpio->gpio, gpio->name))
488 		return -1;
489 	return 0;
490 }
491 
492 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
493 		u8 *array, int count)
494 {
495 	const u8 *cell;
496 	int err;
497 
498 	cell = get_prop_check_min_len(blob, node, prop_name, count, &err);
499 	if (!err)
500 		memcpy(array, cell, count);
501 	return err;
502 }
503 
504 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
505 			     const char *prop_name, int count)
506 {
507 	const u8 *cell;
508 	int err;
509 
510 	cell = get_prop_check_min_len(blob, node, prop_name, count, &err);
511 	if (err)
512 		return NULL;
513 	return cell;
514 }
515