2 * Copyright (c) 2011 The Chromium OS Authors.
3 * SPDX-License-Identifier: GPL-2.0+
10 * This file contains convenience functions for decoding useful and
11 * enlightening information from FDTs. It is intended to be used by device
12 * drivers and board-specific code within U-Boot. It aims to reduce the
13 * amount of FDT munging required within U-Boot itself, so that driver code
14 * changes to support FDT are minimized.
20 * A typedef for a physical address. Note that fdt data is always big
21 * endian even on a litle endian machine.
23 #ifdef CONFIG_PHYS_64BIT
24 typedef u64 fdt_addr_t;
25 typedef u64 fdt_size_t;
26 #define FDT_ADDR_T_NONE (-1ULL)
27 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
28 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
30 typedef u32 fdt_addr_t;
31 typedef u32 fdt_size_t;
32 #define FDT_ADDR_T_NONE (-1U)
33 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
34 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
37 /* Information obtained about memory from the FDT */
44 * Information about a resource. start is the first address of the resource
45 * and end is the last address (inclusive). The length of the resource will
46 * be equal to: end - start + 1.
54 * Compute the size of a resource.
56 * @param res the resource to operate on
57 * @return the size of the resource
59 static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
61 return res->end - res->start + 1;
65 * Compat types that we know about and for which we might have drivers.
66 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
71 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */
72 COMPAT_NVIDIA_TEGRA30_USB, /* Tegra30 USB port */
73 COMPAT_NVIDIA_TEGRA114_USB, /* Tegra114 USB port */
74 COMPAT_NVIDIA_TEGRA114_I2C, /* Tegra114 I2C w/single clock source */
75 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */
76 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */
77 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */
78 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
79 COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */
80 COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */
81 COMPAT_NVIDIA_TEGRA20_PWM, /* Tegra 2 PWM controller */
82 COMPAT_NVIDIA_TEGRA20_DC, /* Tegra 2 Display controller */
83 COMPAT_NVIDIA_TEGRA124_SDMMC, /* Tegra124 SDMMC controller */
84 COMPAT_NVIDIA_TEGRA30_SDMMC, /* Tegra30 SDMMC controller */
85 COMPAT_NVIDIA_TEGRA20_SDMMC, /* Tegra20 SDMMC controller */
86 COMPAT_NVIDIA_TEGRA20_SFLASH, /* Tegra 2 SPI flash controller */
87 COMPAT_NVIDIA_TEGRA20_SLINK, /* Tegra 2 SPI SLINK controller */
88 COMPAT_NVIDIA_TEGRA114_SPI, /* Tegra 114 SPI controller */
89 COMPAT_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */
90 COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */
91 COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */
92 COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */
93 COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */
94 COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */
95 COMPAT_GOOGLE_CROS_EC, /* Google CROS_EC Protocol */
96 COMPAT_GOOGLE_CROS_EC_KEYB, /* Google CROS_EC Keyboard */
97 COMPAT_SAMSUNG_EXYNOS_EHCI, /* Exynos EHCI controller */
98 COMPAT_SAMSUNG_EXYNOS5_XHCI, /* Exynos5 XHCI controller */
99 COMPAT_SAMSUNG_EXYNOS_USB_PHY, /* Exynos phy controller for usb2.0 */
100 COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
101 COMPAT_SAMSUNG_EXYNOS_TMU, /* Exynos TMU */
102 COMPAT_SAMSUNG_EXYNOS_FIMD, /* Exynos Display controller */
103 COMPAT_SAMSUNG_EXYNOS_MIPI_DSI, /* Exynos mipi dsi */
104 COMPAT_SAMSUNG_EXYNOS5_DP, /* Exynos Display port controller */
105 COMPAT_SAMSUNG_EXYNOS_DWMMC, /* Exynos DWMMC controller */
106 COMPAT_SAMSUNG_EXYNOS_MMC, /* Exynos MMC controller */
107 COMPAT_SAMSUNG_EXYNOS_SERIAL, /* Exynos UART */
108 COMPAT_MAXIM_MAX77686_PMIC, /* MAX77686 PMIC */
109 COMPAT_GENERIC_SPI_FLASH, /* Generic SPI Flash chip */
110 COMPAT_MAXIM_98095_CODEC, /* MAX98095 Codec */
111 COMPAT_INFINEON_SLB9635_TPM, /* Infineon SLB9635 TPM */
112 COMPAT_INFINEON_SLB9645_TPM, /* Infineon SLB9645 TPM */
113 COMPAT_SAMSUNG_EXYNOS5_I2C, /* Exynos5 High Speed I2C Controller */
114 COMPAT_SANDBOX_HOST_EMULATION, /* Sandbox emulation of a function */
115 COMPAT_SANDBOX_LCD_SDL, /* Sandbox LCD emulation with SDL */
116 COMPAT_TI_TPS65090, /* Texas Instrument TPS65090 */
117 COMPAT_NXP_PTN3460, /* NXP PTN3460 DP/LVDS bridge */
118 COMPAT_SAMSUNG_EXYNOS_SYSMMU, /* Exynos sysmmu */
119 COMPAT_PARADE_PS8625, /* Parade PS8622 EDP->LVDS bridge */
120 COMPAT_INTEL_LPC, /* Intel Low Pin Count I/F */
121 COMPAT_INTEL_MICROCODE, /* Intel microcode update */
126 /* GPIOs are numbered from 0 */
128 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
130 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
133 /* This is the state of a GPIO pin as defined by the fdt */
134 struct fdt_gpio_state {
135 const char *name; /* name of the fdt property defining this */
136 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
137 u8 flags; /* FDT_GPIO_... flags */
140 /* This tells us whether a fdt_gpio_state record is valid or not */
141 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
144 * Read the GPIO taking into account the polarity of the pin.
146 * @param gpio pointer to the decoded gpio
147 * @return value of the gpio if successful, < 0 if unsuccessful
149 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
152 * Write the GPIO taking into account the polarity of the pin.
154 * @param gpio pointer to the decoded gpio
155 * @return 0 if successful
157 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
160 * Find the next numbered alias for a peripheral. This is used to enumerate
161 * all the peripherals of a certain type.
163 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
164 * this function will return a pointer to the node the alias points to, and
165 * then update *upto to 1. Next time you call this function, the next node
168 * All nodes returned will match the compatible ID, as it is assumed that
169 * all peripherals use the same driver.
171 * @param blob FDT blob to use
172 * @param name Root name of alias to search for
173 * @param id Compatible ID to look for
174 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
176 int fdtdec_next_alias(const void *blob, const char *name,
177 enum fdt_compat_id id, int *upto);
180 * Find the compatible ID for a given node.
182 * Generally each node has at least one compatible string attached to it.
183 * This function looks through our list of known compatible strings and
184 * returns the corresponding ID which matches the compatible string.
186 * @param blob FDT blob to use
187 * @param node Node containing compatible string to find
188 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
190 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
193 * Find the next compatible node for a peripheral.
195 * Do the first call with node = 0. This function will return a pointer to
196 * the next compatible node. Next time you call this function, pass the
197 * value returned, and the next node will be provided.
199 * @param blob FDT blob to use
200 * @param node Start node for search
201 * @param id Compatible ID to look for (enum fdt_compat_id)
202 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
204 int fdtdec_next_compatible(const void *blob, int node,
205 enum fdt_compat_id id);
208 * Find the next compatible subnode for a peripheral.
210 * Do the first call with node set to the parent and depth = 0. This
211 * function will return the offset of the next compatible node. Next time
212 * you call this function, pass the node value returned last time, with
213 * depth unchanged, and the next node will be provided.
215 * @param blob FDT blob to use
216 * @param node Start node for search
217 * @param id Compatible ID to look for (enum fdt_compat_id)
218 * @param depthp Current depth (set to 0 before first call)
219 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
221 int fdtdec_next_compatible_subnode(const void *blob, int node,
222 enum fdt_compat_id id, int *depthp);
225 * Look up an address property in a node and return it as an address.
226 * The property must hold either one address with no trailing data or
227 * one address with a length. This is only tested on 32-bit machines.
229 * @param blob FDT blob
230 * @param node node to examine
231 * @param prop_name name of property to find
232 * @return address, if found, or FDT_ADDR_T_NONE if not
234 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
235 const char *prop_name);
238 * Look up an address property in a node and return it as an address.
239 * The property must hold one address with a length. This is only tested
240 * on 32-bit machines.
242 * @param blob FDT blob
243 * @param node node to examine
244 * @param prop_name name of property to find
245 * @return address, if found, or FDT_ADDR_T_NONE if not
247 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
248 const char *prop_name, fdt_size_t *sizep);
251 * Look up a 32-bit integer property in a node and return it. The property
252 * must have at least 4 bytes of data. The value of the first cell is
255 * @param blob FDT blob
256 * @param node node to examine
257 * @param prop_name name of property to find
258 * @param default_val default value to return if the property is not found
259 * @return integer value, if found, or default_val if not
261 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
265 * Look up a 64-bit integer property in a node and return it. The property
266 * must have at least 8 bytes of data (2 cells). The first two cells are
267 * concatenated to form a 8 bytes value, where the first cell is top half and
268 * the second cell is bottom half.
270 * @param blob FDT blob
271 * @param node node to examine
272 * @param prop_name name of property to find
273 * @param default_val default value to return if the property is not found
274 * @return integer value, if found, or default_val if not
276 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
277 uint64_t default_val);
280 * Checks whether a node is enabled.
281 * This looks for a 'status' property. If this exists, then returns 1 if
282 * the status is 'ok' and 0 otherwise. If there is no status property,
283 * it returns 1 on the assumption that anything mentioned should be enabled
286 * @param blob FDT blob
287 * @param node node to examine
288 * @return integer value 0 (not enabled) or 1 (enabled)
290 int fdtdec_get_is_enabled(const void *blob, int node);
293 * Make sure we have a valid fdt available to control U-Boot.
295 * If not, a message is printed to the console if the console is ready.
297 * @return 0 if all ok, -1 if not
299 int fdtdec_prepare_fdt(void);
302 * Checks that we have a valid fdt available to control U-Boot.
304 * However, if not then for the moment nothing is done, since this function
305 * is called too early to panic().
309 int fdtdec_check_fdt(void);
312 * Find the nodes for a peripheral and return a list of them in the correct
313 * order. This is used to enumerate all the peripherals of a certain type.
315 * To use this, optionally set up a /aliases node with alias properties for
316 * a peripheral. For example, for usb you could have:
319 * usb0 = "/ehci@c5008000";
320 * usb1 = "/ehci@c5000000";
323 * Pass "usb" as the name to this function and will return a list of two
324 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
326 * All nodes returned will match the compatible ID, as it is assumed that
327 * all peripherals use the same driver.
329 * If no alias node is found, then the node list will be returned in the
330 * order found in the fdt. If the aliases mention a node which doesn't
331 * exist, then this will be ignored. If nodes are found with no aliases,
332 * they will be added in any order.
334 * If there is a gap in the aliases, then this function return a 0 node at
335 * that position. The return value will also count these gaps.
337 * This function checks node properties and will not return nodes which are
338 * marked disabled (status = "disabled").
340 * @param blob FDT blob to use
341 * @param name Root name of alias to search for
342 * @param id Compatible ID to look for
343 * @param node_list Place to put list of found nodes
344 * @param maxcount Maximum number of nodes to find
345 * @return number of nodes found on success, FTD_ERR_... on error
347 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
348 enum fdt_compat_id id, int *node_list, int maxcount);
351 * This function is similar to fdtdec_find_aliases_for_id() except that it
352 * adds to the node_list that is passed in. Any 0 elements are considered
353 * available for allocation - others are considered already used and are
356 * You can use this by calling fdtdec_find_aliases_for_id() with an
357 * uninitialised array, then setting the elements that are returned to -1,
358 * say, then calling this function, perhaps with a different compat id.
359 * Any elements you get back that are >0 are new nodes added by the call
362 * Note that if you have some nodes with aliases and some without, you are
363 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
364 * one compat_id may fill in positions for which you have aliases defined
365 * for another compat_id. When you later call *this* function with the second
366 * compat_id, the alias positions may already be used. A debug warning may
367 * be generated in this case, but it is safest to define aliases for all
368 * nodes when you care about the ordering.
370 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
371 enum fdt_compat_id id, int *node_list, int maxcount);
374 * Get the alias sequence number of a node
376 * This works out whether a node is pointed to by an alias, and if so, the
377 * sequence number of that alias. Aliases are of the form <base><num> where
378 * <num> is the sequence number. For example spi2 would be sequence number
381 * @param blob Device tree blob (if NULL, then error is returned)
382 * @param base Base name for alias (before the underscore)
383 * @param node Node to look up
384 * @param seqp This is set to the sequence number if one is found,
385 * but otherwise the value is left alone
386 * @return 0 if a sequence was found, -ve if not
388 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
392 * Get the offset of the given alias node
394 * This looks up an alias in /aliases then finds the offset of that node.
396 * @param blob Device tree blob (if NULL, then error is returned)
397 * @param name Alias name, e.g. "console"
398 * @return Node offset referred to by that alias, or -ve FDT_ERR_...
400 int fdtdec_get_alias_node(const void *blob, const char *name);
403 * Get the offset of the given chosen node
405 * This looks up a property in /chosen containing the path to another node,
406 * then finds the offset of that node.
408 * @param blob Device tree blob (if NULL, then error is returned)
409 * @param name Property name, e.g. "stdout-path"
410 * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
412 int fdtdec_get_chosen_node(const void *blob, const char *name);
415 * Get the name for a compatible ID
417 * @param id Compatible ID to look for
418 * @return compatible string for that id
420 const char *fdtdec_get_compatible(enum fdt_compat_id id);
422 /* Look up a phandle and follow it to its node. Then return the offset
425 * @param blob FDT blob
426 * @param node node to examine
427 * @param prop_name name of property to find
428 * @return node offset if found, -ve error code on error
430 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
433 * Look up a property in a node and return its contents in an integer
434 * array of given length. The property must have at least enough data for
435 * the array (4*count bytes). It may have more, but this will be ignored.
437 * @param blob FDT blob
438 * @param node node to examine
439 * @param prop_name name of property to find
440 * @param array array to fill with data
441 * @param count number of array elements
442 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
443 * or -FDT_ERR_BADLAYOUT if not enough data
445 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
446 u32 *array, int count);
449 * Look up a property in a node and return its contents in an integer
450 * array of given length. The property must exist but may have less data that
451 * expected (4*count bytes). It may have more, but this will be ignored.
453 * @param blob FDT blob
454 * @param node node to examine
455 * @param prop_name name of property to find
456 * @param array array to fill with data
457 * @param count number of array elements
458 * @return number of array elements if ok, or -FDT_ERR_NOTFOUND if the
459 * property is not found
461 int fdtdec_get_int_array_count(const void *blob, int node,
462 const char *prop_name, u32 *array, int count);
465 * Look up a property in a node and return a pointer to its contents as a
466 * unsigned int array of given length. The property must have at least enough
467 * data for the array ('count' cells). It may have more, but this will be
468 * ignored. The data is not copied.
470 * Note that you must access elements of the array with fdt32_to_cpu(),
471 * since the elements will be big endian even on a little endian machine.
473 * @param blob FDT blob
474 * @param node node to examine
475 * @param prop_name name of property to find
476 * @param count number of array elements
477 * @return pointer to array if found, or NULL if the property is not
478 * found or there is not enough data
480 const u32 *fdtdec_locate_array(const void *blob, int node,
481 const char *prop_name, int count);
484 * Look up a boolean property in a node and return it.
486 * A boolean properly is true if present in the device tree and false if not
487 * present, regardless of its value.
489 * @param blob FDT blob
490 * @param node node to examine
491 * @param prop_name name of property to find
492 * @return 1 if the properly is present; 0 if it isn't present
494 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
497 * Decode a single GPIOs from an FDT.
499 * If the property is not found, then the GPIO structure will still be
500 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
501 * provide optional GPIOs.
503 * @param blob FDT blob to use
504 * @param node Node to look at
505 * @param prop_name Node property name
506 * @param gpio gpio elements to fill from FDT
507 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
509 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
510 struct fdt_gpio_state *gpio);
513 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
516 * @param blob FDT blob to use
517 * @param node Node to look at
518 * @param prop_name Node property name
519 * @param gpio Array of gpio elements to fill from FDT. This will be
520 * untouched if either 0 or an error is returned
521 * @param max_count Maximum number of elements allowed
522 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
523 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
525 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
526 struct fdt_gpio_state *gpio, int max_count);
529 * Set up a GPIO pin according to the provided gpio information. At present this
530 * just requests the GPIO.
532 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
533 * deal with optional GPIOs.
535 * @param gpio GPIO info to use for set up
536 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
538 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
541 * Look in the FDT for a config item with the given name and return its value
542 * as a 32-bit integer. The property must have at least 4 bytes of data. The
543 * value of the first cell is returned.
545 * @param blob FDT blob to use
546 * @param prop_name Node property name
547 * @param default_val default value to return if the property is not found
548 * @return integer value, if found, or default_val if not
550 int fdtdec_get_config_int(const void *blob, const char *prop_name,
554 * Look in the FDT for a config item with the given name
555 * and return whether it exists.
557 * @param blob FDT blob
558 * @param prop_name property name to look up
559 * @return 1, if it exists, or 0 if not
561 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
564 * Look in the FDT for a config item with the given name and return its value
567 * @param blob FDT blob
568 * @param prop_name property name to look up
569 * @returns property string, NULL on error.
571 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
574 * Look up a property in a node and return its contents in a byte
575 * array of given length. The property must have at least enough data for
576 * the array (count bytes). It may have more, but this will be ignored.
578 * @param blob FDT blob
579 * @param node node to examine
580 * @param prop_name name of property to find
581 * @param array array to fill with data
582 * @param count number of array elements
583 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
584 * or -FDT_ERR_BADLAYOUT if not enough data
586 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
587 u8 *array, int count);
590 * Look up a property in a node and return a pointer to its contents as a
591 * byte array of given length. The property must have at least enough data
592 * for the array (count bytes). It may have more, but this will be ignored.
593 * The data is not copied.
595 * @param blob FDT blob
596 * @param node node to examine
597 * @param prop_name name of property to find
598 * @param count number of array elements
599 * @return pointer to byte array if found, or NULL if the property is not
600 * found or there is not enough data
602 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
603 const char *prop_name, int count);
606 * Look up a property in a node which contains a memory region address and
607 * size. Then return a pointer to this address.
609 * The property must hold one address with a length. This is only tested on
612 * @param blob FDT blob
613 * @param node node to examine
614 * @param prop_name name of property to find
615 * @param ptrp returns pointer to region, or NULL if no address
616 * @param size returns size of region
617 * @return 0 if ok, -1 on error (propery not found)
619 int fdtdec_decode_region(const void *blob, int node,
620 const char *prop_name, void **ptrp, size_t *size);
622 /* A flash map entry, containing an offset and length */
629 * Read a flash entry from the fdt
631 * @param blob FDT blob
632 * @param node Offset of node to read
633 * @param name Name of node being read
634 * @param entry Place to put offset and size of this node
635 * @return 0 if ok, -ve on error
637 int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
638 struct fmap_entry *entry);
641 * Obtain an indexed resource from a device property.
643 * @param fdt FDT blob
644 * @param node node to examine
645 * @param property name of the property to parse
646 * @param index index of the resource to retrieve
647 * @param res returns the resource
648 * @return 0 if ok, negative on error
650 int fdt_get_resource(const void *fdt, int node, const char *property,
651 unsigned int index, struct fdt_resource *res);
654 * Obtain a named resource from a device property.
656 * Look up the index of the name in a list of strings and return the resource
659 * @param fdt FDT blob
660 * @param node node to examine
661 * @param property name of the property to parse
662 * @param prop_names name of the property containing the list of names
663 * @param name the name of the entry to look up
664 * @param res returns the resource
666 int fdt_get_named_resource(const void *fdt, int node, const char *property,
667 const char *prop_names, const char *name,
668 struct fdt_resource *res);
671 * Look at the reg property of a device node that represents a PCI device
672 * and parse the bus, device and function number from it.
674 * @param fdt FDT blob
675 * @param node node to examine
676 * @param bdf returns bus, device, function triplet
677 * @return 0 if ok, negative on error
679 int fdtdec_pci_get_bdf(const void *fdt, int node, int *bdf);