xref: /openbmc/u-boot/include/fdtdec.h (revision 32c81ea6)
1 /*
2  * Copyright (c) 2011 The Chromium OS Authors.
3  * SPDX-License-Identifier:	GPL-2.0+
4  */
5 
6 #ifndef __fdtdec_h
7 #define __fdtdec_h
8 
9 /*
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.
15  */
16 
17 #include <libfdt.h>
18 
19 /*
20  * A typedef for a physical address. Note that fdt data is always big
21  * endian even on a litle endian machine.
22  */
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)
29 #else
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)
35 #endif
36 
37 /* Information obtained about memory from the FDT */
38 struct fdt_memory {
39 	fdt_addr_t start;
40 	fdt_addr_t end;
41 };
42 
43 /*
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.
47  */
48 struct fdt_resource {
49 	fdt_addr_t start;
50 	fdt_addr_t end;
51 };
52 
53 /**
54  * Compute the size of a resource.
55  *
56  * @param res	the resource to operate on
57  * @return the size of the resource
58  */
59 static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
60 {
61 	return res->end - res->start + 1;
62 }
63 
64 /**
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
67  * within drivers.
68  */
69 enum fdt_compat_id {
70 	COMPAT_UNKNOWN,
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 
122 	COMPAT_COUNT,
123 };
124 
125 /* GPIOs are numbered from 0 */
126 enum {
127 	FDT_GPIO_NONE = -1U,	/* an invalid GPIO used to end our list */
128 
129 	FDT_GPIO_ACTIVE_LOW = 1 << 0,	/* input is active low (else high) */
130 };
131 
132 /* This is the state of a GPIO pin as defined by the fdt */
133 struct fdt_gpio_state {
134 	const char *name;	/* name of the fdt property defining this */
135 	uint gpio;		/* GPIO number, or FDT_GPIO_NONE if none */
136 	u8 flags;		/* FDT_GPIO_... flags */
137 };
138 
139 /* This tells us whether a fdt_gpio_state record is valid or not */
140 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
141 
142 /**
143  * Read the GPIO taking into account the polarity of the pin.
144  *
145  * @param gpio		pointer to the decoded gpio
146  * @return value of the gpio if successful, < 0 if unsuccessful
147  */
148 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
149 
150 /**
151  * Write the GPIO taking into account the polarity of the pin.
152  *
153  * @param gpio		pointer to the decoded gpio
154  * @return 0 if successful
155  */
156 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
157 
158 /**
159  * Find the next numbered alias for a peripheral. This is used to enumerate
160  * all the peripherals of a certain type.
161  *
162  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
163  * this function will return a pointer to the node the alias points to, and
164  * then update *upto to 1. Next time you call this function, the next node
165  * will be returned.
166  *
167  * All nodes returned will match the compatible ID, as it is assumed that
168  * all peripherals use the same driver.
169  *
170  * @param blob		FDT blob to use
171  * @param name		Root name of alias to search for
172  * @param id		Compatible ID to look for
173  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
174  */
175 int fdtdec_next_alias(const void *blob, const char *name,
176 		enum fdt_compat_id id, int *upto);
177 
178 /**
179  * Find the compatible ID for a given node.
180  *
181  * Generally each node has at least one compatible string attached to it.
182  * This function looks through our list of known compatible strings and
183  * returns the corresponding ID which matches the compatible string.
184  *
185  * @param blob		FDT blob to use
186  * @param node		Node containing compatible string to find
187  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
188  */
189 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
190 
191 /**
192  * Find the next compatible node for a peripheral.
193  *
194  * Do the first call with node = 0. This function will return a pointer to
195  * the next compatible node. Next time you call this function, pass the
196  * value returned, and the next node will be provided.
197  *
198  * @param blob		FDT blob to use
199  * @param node		Start node for search
200  * @param id		Compatible ID to look for (enum fdt_compat_id)
201  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
202  */
203 int fdtdec_next_compatible(const void *blob, int node,
204 		enum fdt_compat_id id);
205 
206 /**
207  * Find the next compatible subnode for a peripheral.
208  *
209  * Do the first call with node set to the parent and depth = 0. This
210  * function will return the offset of the next compatible node. Next time
211  * you call this function, pass the node value returned last time, with
212  * depth unchanged, and the next node will be provided.
213  *
214  * @param blob		FDT blob to use
215  * @param node		Start node for search
216  * @param id		Compatible ID to look for (enum fdt_compat_id)
217  * @param depthp	Current depth (set to 0 before first call)
218  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
219  */
220 int fdtdec_next_compatible_subnode(const void *blob, int node,
221 		enum fdt_compat_id id, int *depthp);
222 
223 /**
224  * Look up an address property in a node and return it as an address.
225  * The property must hold either one address with no trailing data or
226  * one address with a length. This is only tested on 32-bit machines.
227  *
228  * @param blob	FDT blob
229  * @param node	node to examine
230  * @param prop_name	name of property to find
231  * @return address, if found, or FDT_ADDR_T_NONE if not
232  */
233 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
234 		const char *prop_name);
235 
236 /**
237  * Look up an address property in a node and return it as an address.
238  * The property must hold one address with a length. This is only tested
239  * on 32-bit machines.
240  *
241  * @param blob	FDT blob
242  * @param node	node to examine
243  * @param prop_name	name of property to find
244  * @return address, if found, or FDT_ADDR_T_NONE if not
245  */
246 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
247 		const char *prop_name, fdt_size_t *sizep);
248 
249 /**
250  * Look up a 32-bit integer property in a node and return it. The property
251  * must have at least 4 bytes of data. The value of the first cell is
252  * returned.
253  *
254  * @param blob	FDT blob
255  * @param node	node to examine
256  * @param prop_name	name of property to find
257  * @param default_val	default value to return if the property is not found
258  * @return integer value, if found, or default_val if not
259  */
260 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
261 		s32 default_val);
262 
263 /**
264  * Look up a 64-bit integer property in a node and return it. The property
265  * must have at least 8 bytes of data (2 cells). The first two cells are
266  * concatenated to form a 8 bytes value, where the first cell is top half and
267  * the second cell is bottom half.
268  *
269  * @param blob	FDT blob
270  * @param node	node to examine
271  * @param prop_name	name of property to find
272  * @param default_val	default value to return if the property is not found
273  * @return integer value, if found, or default_val if not
274  */
275 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
276 		uint64_t default_val);
277 
278 /**
279  * Checks whether a node is enabled.
280  * This looks for a 'status' property. If this exists, then returns 1 if
281  * the status is 'ok' and 0 otherwise. If there is no status property,
282  * it returns 1 on the assumption that anything mentioned should be enabled
283  * by default.
284  *
285  * @param blob	FDT blob
286  * @param node	node to examine
287  * @return integer value 0 (not enabled) or 1 (enabled)
288  */
289 int fdtdec_get_is_enabled(const void *blob, int node);
290 
291 /**
292  * Make sure we have a valid fdt available to control U-Boot.
293  *
294  * If not, a message is printed to the console if the console is ready.
295  *
296  * @return 0 if all ok, -1 if not
297  */
298 int fdtdec_prepare_fdt(void);
299 
300 /**
301  * Checks that we have a valid fdt available to control U-Boot.
302 
303  * However, if not then for the moment nothing is done, since this function
304  * is called too early to panic().
305  *
306  * @returns 0
307  */
308 int fdtdec_check_fdt(void);
309 
310 /**
311  * Find the nodes for a peripheral and return a list of them in the correct
312  * order. This is used to enumerate all the peripherals of a certain type.
313  *
314  * To use this, optionally set up a /aliases node with alias properties for
315  * a peripheral. For example, for usb you could have:
316  *
317  * aliases {
318  *		usb0 = "/ehci@c5008000";
319  *		usb1 = "/ehci@c5000000";
320  * };
321  *
322  * Pass "usb" as the name to this function and will return a list of two
323  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
324  *
325  * All nodes returned will match the compatible ID, as it is assumed that
326  * all peripherals use the same driver.
327  *
328  * If no alias node is found, then the node list will be returned in the
329  * order found in the fdt. If the aliases mention a node which doesn't
330  * exist, then this will be ignored. If nodes are found with no aliases,
331  * they will be added in any order.
332  *
333  * If there is a gap in the aliases, then this function return a 0 node at
334  * that position. The return value will also count these gaps.
335  *
336  * This function checks node properties and will not return nodes which are
337  * marked disabled (status = "disabled").
338  *
339  * @param blob		FDT blob to use
340  * @param name		Root name of alias to search for
341  * @param id		Compatible ID to look for
342  * @param node_list	Place to put list of found nodes
343  * @param maxcount	Maximum number of nodes to find
344  * @return number of nodes found on success, FTD_ERR_... on error
345  */
346 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
347 			enum fdt_compat_id id, int *node_list, int maxcount);
348 
349 /*
350  * This function is similar to fdtdec_find_aliases_for_id() except that it
351  * adds to the node_list that is passed in. Any 0 elements are considered
352  * available for allocation - others are considered already used and are
353  * skipped.
354  *
355  * You can use this by calling fdtdec_find_aliases_for_id() with an
356  * uninitialised array, then setting the elements that are returned to -1,
357  * say, then calling this function, perhaps with a different compat id.
358  * Any elements you get back that are >0 are new nodes added by the call
359  * to this function.
360  *
361  * Note that if you have some nodes with aliases and some without, you are
362  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
363  * one compat_id may fill in positions for which you have aliases defined
364  * for another compat_id. When you later call *this* function with the second
365  * compat_id, the alias positions may already be used. A debug warning may
366  * be generated in this case, but it is safest to define aliases for all
367  * nodes when you care about the ordering.
368  */
369 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
370 			enum fdt_compat_id id, int *node_list, int maxcount);
371 
372 /**
373  * Get the alias sequence number of a node
374  *
375  * This works out whether a node is pointed to by an alias, and if so, the
376  * sequence number of that alias. Aliases are of the form <base><num> where
377  * <num> is the sequence number. For example spi2 would be sequence number
378  * 2.
379  *
380  * @param blob		Device tree blob (if NULL, then error is returned)
381  * @param base		Base name for alias (before the underscore)
382  * @param node		Node to look up
383  * @param seqp		This is set to the sequence number if one is found,
384  *			but otherwise the value is left alone
385  * @return 0 if a sequence was found, -ve if not
386  */
387 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
388 			 int *seqp);
389 
390 /**
391  * Get the offset of the given alias node
392  *
393  * This looks up an alias in /aliases then finds the offset of that node.
394  *
395  * @param blob		Device tree blob (if NULL, then error is returned)
396  * @param name		Alias name, e.g. "console"
397  * @return Node offset referred to by that alias, or -ve FDT_ERR_...
398  */
399 int fdtdec_get_alias_node(const void *blob, const char *name);
400 
401 /**
402  * Get the offset of the given chosen node
403  *
404  * This looks up a property in /chosen containing the path to another node,
405  * then finds the offset of that node.
406  *
407  * @param blob		Device tree blob (if NULL, then error is returned)
408  * @param name		Property name, e.g. "stdout-path"
409  * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
410  */
411 int fdtdec_get_chosen_node(const void *blob, const char *name);
412 
413 /*
414  * Get the name for a compatible ID
415  *
416  * @param id		Compatible ID to look for
417  * @return compatible string for that id
418  */
419 const char *fdtdec_get_compatible(enum fdt_compat_id id);
420 
421 /* Look up a phandle and follow it to its node. Then return the offset
422  * of that node.
423  *
424  * @param blob		FDT blob
425  * @param node		node to examine
426  * @param prop_name	name of property to find
427  * @return node offset if found, -ve error code on error
428  */
429 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
430 
431 /**
432  * Look up a property in a node and return its contents in an integer
433  * array of given length. The property must have at least enough data for
434  * the array (4*count bytes). It may have more, but this will be ignored.
435  *
436  * @param blob		FDT blob
437  * @param node		node to examine
438  * @param prop_name	name of property to find
439  * @param array		array to fill with data
440  * @param count		number of array elements
441  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
442  *		or -FDT_ERR_BADLAYOUT if not enough data
443  */
444 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
445 		u32 *array, int count);
446 
447 /**
448  * Look up a property in a node and return a pointer to its contents as a
449  * unsigned int array of given length. The property must have at least enough
450  * data for the array ('count' cells). It may have more, but this will be
451  * ignored. The data is not copied.
452  *
453  * Note that you must access elements of the array with fdt32_to_cpu(),
454  * since the elements will be big endian even on a little endian machine.
455  *
456  * @param blob		FDT blob
457  * @param node		node to examine
458  * @param prop_name	name of property to find
459  * @param count		number of array elements
460  * @return pointer to array if found, or NULL if the property is not
461  *		found or there is not enough data
462  */
463 const u32 *fdtdec_locate_array(const void *blob, int node,
464 			       const char *prop_name, int count);
465 
466 /**
467  * Look up a boolean property in a node and return it.
468  *
469  * A boolean properly is true if present in the device tree and false if not
470  * present, regardless of its value.
471  *
472  * @param blob	FDT blob
473  * @param node	node to examine
474  * @param prop_name	name of property to find
475  * @return 1 if the properly is present; 0 if it isn't present
476  */
477 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
478 
479 /**
480  * Decode a single GPIOs from an FDT.
481  *
482  * If the property is not found, then the GPIO structure will still be
483  * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
484  * provide optional GPIOs.
485  *
486  * @param blob		FDT blob to use
487  * @param node		Node to look at
488  * @param prop_name	Node property name
489  * @param gpio		gpio elements to fill from FDT
490  * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
491  */
492 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
493 		struct fdt_gpio_state *gpio);
494 
495 /**
496  * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
497  * terminating item.
498  *
499  * @param blob         FDT blob to use
500  * @param node         Node to look at
501  * @param prop_name    Node property name
502  * @param gpio         Array of gpio elements to fill from FDT. This will be
503  *                     untouched if either 0 or an error is returned
504  * @param max_count    Maximum number of elements allowed
505  * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
506  * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
507  */
508 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
509 		struct fdt_gpio_state *gpio, int max_count);
510 
511 /**
512  * Set up a GPIO pin according to the provided gpio information. At present this
513  * just requests the GPIO.
514  *
515  * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
516  * deal with optional GPIOs.
517  *
518  * @param gpio		GPIO info to use for set up
519  * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
520  */
521 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
522 
523 /**
524  * Look in the FDT for a config item with the given name and return its value
525  * as a 32-bit integer. The property must have at least 4 bytes of data. The
526  * value of the first cell is returned.
527  *
528  * @param blob		FDT blob to use
529  * @param prop_name	Node property name
530  * @param default_val	default value to return if the property is not found
531  * @return integer value, if found, or default_val if not
532  */
533 int fdtdec_get_config_int(const void *blob, const char *prop_name,
534 		int default_val);
535 
536 /**
537  * Look in the FDT for a config item with the given name
538  * and return whether it exists.
539  *
540  * @param blob		FDT blob
541  * @param prop_name	property name to look up
542  * @return 1, if it exists, or 0 if not
543  */
544 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
545 
546 /**
547  * Look in the FDT for a config item with the given name and return its value
548  * as a string.
549  *
550  * @param blob          FDT blob
551  * @param prop_name     property name to look up
552  * @returns property string, NULL on error.
553  */
554 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
555 
556 /*
557  * Look up a property in a node and return its contents in a byte
558  * array of given length. The property must have at least enough data for
559  * the array (count bytes). It may have more, but this will be ignored.
560  *
561  * @param blob		FDT blob
562  * @param node		node to examine
563  * @param prop_name	name of property to find
564  * @param array		array to fill with data
565  * @param count		number of array elements
566  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
567  *		or -FDT_ERR_BADLAYOUT if not enough data
568  */
569 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
570 		u8 *array, int count);
571 
572 /**
573  * Look up a property in a node and return a pointer to its contents as a
574  * byte array of given length. The property must have at least enough data
575  * for the array (count bytes). It may have more, but this will be ignored.
576  * The data is not copied.
577  *
578  * @param blob		FDT blob
579  * @param node		node to examine
580  * @param prop_name	name of property to find
581  * @param count		number of array elements
582  * @return pointer to byte array if found, or NULL if the property is not
583  *		found or there is not enough data
584  */
585 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
586 			     const char *prop_name, int count);
587 
588 /**
589  * Look up a property in a node which contains a memory region address and
590  * size. Then return a pointer to this address.
591  *
592  * The property must hold one address with a length. This is only tested on
593  * 32-bit machines.
594  *
595  * @param blob		FDT blob
596  * @param node		node to examine
597  * @param prop_name	name of property to find
598  * @param ptrp		returns pointer to region, or NULL if no address
599  * @param size		returns size of region
600  * @return 0 if ok, -1 on error (propery not found)
601  */
602 int fdtdec_decode_region(const void *blob, int node,
603 		const char *prop_name, void **ptrp, size_t *size);
604 
605 /* A flash map entry, containing an offset and length */
606 struct fmap_entry {
607 	uint32_t offset;
608 	uint32_t length;
609 };
610 
611 /**
612  * Read a flash entry from the fdt
613  *
614  * @param blob		FDT blob
615  * @param node		Offset of node to read
616  * @param name		Name of node being read
617  * @param entry		Place to put offset and size of this node
618  * @return 0 if ok, -ve on error
619  */
620 int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
621 			   struct fmap_entry *entry);
622 
623 /**
624  * Obtain an indexed resource from a device property.
625  *
626  * @param fdt		FDT blob
627  * @param node		node to examine
628  * @param property	name of the property to parse
629  * @param index		index of the resource to retrieve
630  * @param res		returns the resource
631  * @return 0 if ok, negative on error
632  */
633 int fdt_get_resource(const void *fdt, int node, const char *property,
634 		     unsigned int index, struct fdt_resource *res);
635 
636 /**
637  * Obtain a named resource from a device property.
638  *
639  * Look up the index of the name in a list of strings and return the resource
640  * at that index.
641  *
642  * @param fdt		FDT blob
643  * @param node		node to examine
644  * @param property	name of the property to parse
645  * @param prop_names	name of the property containing the list of names
646  * @param name		the name of the entry to look up
647  * @param res		returns the resource
648  */
649 int fdt_get_named_resource(const void *fdt, int node, const char *property,
650 			   const char *prop_names, const char *name,
651 			   struct fdt_resource *res);
652 
653 /**
654  * Look at the reg property of a device node that represents a PCI device
655  * and parse the bus, device and function number from it.
656  *
657  * @param fdt		FDT blob
658  * @param node		node to examine
659  * @param bdf		returns bus, device, function triplet
660  * @return 0 if ok, negative on error
661  */
662 int fdtdec_pci_get_bdf(const void *fdt, int node, int *bdf);
663 
664 #endif
665