xref: /openbmc/u-boot/include/fdtdec.h (revision e9c891ff)
1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors.
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 <linux/libfdt.h>
18 #include <pci.h>
19 
20 /*
21  * A typedef for a physical address. Note that fdt data is always big
22  * endian even on a litle endian machine.
23  */
24 typedef phys_addr_t fdt_addr_t;
25 typedef phys_size_t fdt_size_t;
26 #ifdef CONFIG_PHYS_64BIT
27 #define FDT_ADDR_T_NONE (-1U)
28 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
29 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
30 typedef fdt64_t fdt_val_t;
31 #else
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 typedef fdt32_t fdt_val_t;
36 #endif
37 
38 /* Information obtained about memory from the FDT */
39 struct fdt_memory {
40 	fdt_addr_t start;
41 	fdt_addr_t end;
42 };
43 
44 #ifdef CONFIG_SPL_BUILD
45 #define SPL_BUILD	1
46 #else
47 #define SPL_BUILD	0
48 #endif
49 
50 /*
51  * Information about a resource. start is the first address of the resource
52  * and end is the last address (inclusive). The length of the resource will
53  * be equal to: end - start + 1.
54  */
55 struct fdt_resource {
56 	fdt_addr_t start;
57 	fdt_addr_t end;
58 };
59 
60 enum fdt_pci_space {
61 	FDT_PCI_SPACE_CONFIG = 0,
62 	FDT_PCI_SPACE_IO = 0x01000000,
63 	FDT_PCI_SPACE_MEM32 = 0x02000000,
64 	FDT_PCI_SPACE_MEM64 = 0x03000000,
65 	FDT_PCI_SPACE_MEM32_PREF = 0x42000000,
66 	FDT_PCI_SPACE_MEM64_PREF = 0x43000000,
67 };
68 
69 #define FDT_PCI_ADDR_CELLS	3
70 #define FDT_PCI_SIZE_CELLS	2
71 #define FDT_PCI_REG_SIZE	\
72 	((FDT_PCI_ADDR_CELLS + FDT_PCI_SIZE_CELLS) * sizeof(u32))
73 
74 /*
75  * The Open Firmware spec defines PCI physical address as follows:
76  *
77  *          bits# 31 .... 24 23 .... 16 15 .... 08 07 .... 00
78  *
79  * phys.hi  cell:  npt000ss   bbbbbbbb   dddddfff   rrrrrrrr
80  * phys.mid cell:  hhhhhhhh   hhhhhhhh   hhhhhhhh   hhhhhhhh
81  * phys.lo  cell:  llllllll   llllllll   llllllll   llllllll
82  *
83  * where:
84  *
85  * n:        is 0 if the address is relocatable, 1 otherwise
86  * p:        is 1 if addressable region is prefetchable, 0 otherwise
87  * t:        is 1 if the address is aliased (for non-relocatable I/O) below 1MB
88  *           (for Memory), or below 64KB (for relocatable I/O)
89  * ss:       is the space code, denoting the address space
90  * bbbbbbbb: is the 8-bit Bus Number
91  * ddddd:    is the 5-bit Device Number
92  * fff:      is the 3-bit Function Number
93  * rrrrrrrr: is the 8-bit Register Number
94  * hhhhhhhh: is a 32-bit unsigned number
95  * llllllll: is a 32-bit unsigned number
96  */
97 struct fdt_pci_addr {
98 	u32	phys_hi;
99 	u32	phys_mid;
100 	u32	phys_lo;
101 };
102 
103 /**
104  * Compute the size of a resource.
105  *
106  * @param res	the resource to operate on
107  * @return the size of the resource
108  */
109 static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
110 {
111 	return res->end - res->start + 1;
112 }
113 
114 /**
115  * Compat types that we know about and for which we might have drivers.
116  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
117  * within drivers.
118  */
119 enum fdt_compat_id {
120 	COMPAT_UNKNOWN,
121 	COMPAT_NVIDIA_TEGRA20_EMC,	/* Tegra20 memory controller */
122 	COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
123 	COMPAT_NVIDIA_TEGRA20_NAND,	/* Tegra2 NAND controller */
124 	COMPAT_NVIDIA_TEGRA124_XUSB_PADCTL,
125 					/* Tegra124 XUSB pad controller */
126 	COMPAT_NVIDIA_TEGRA210_XUSB_PADCTL,
127 					/* Tegra210 XUSB pad controller */
128 	COMPAT_SMSC_LAN9215,		/* SMSC 10/100 Ethernet LAN9215 */
129 	COMPAT_SAMSUNG_EXYNOS5_SROMC,	/* Exynos5 SROMC */
130 	COMPAT_SAMSUNG_S3C2440_I2C,	/* Exynos I2C Controller */
131 	COMPAT_SAMSUNG_EXYNOS5_SOUND,	/* Exynos Sound */
132 	COMPAT_WOLFSON_WM8994_CODEC,	/* Wolfson WM8994 Sound Codec */
133 	COMPAT_SAMSUNG_EXYNOS_USB_PHY,	/* Exynos phy controller for usb2.0 */
134 	COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
135 	COMPAT_SAMSUNG_EXYNOS_TMU,	/* Exynos TMU */
136 	COMPAT_SAMSUNG_EXYNOS_MIPI_DSI,	/* Exynos mipi dsi */
137 	COMPAT_SAMSUNG_EXYNOS_DWMMC,	/* Exynos DWMMC controller */
138 	COMPAT_SAMSUNG_EXYNOS_MMC,	/* Exynos MMC controller */
139 	COMPAT_GENERIC_SPI_FLASH,	/* Generic SPI Flash chip */
140 	COMPAT_MAXIM_98095_CODEC,	/* MAX98095 Codec */
141 	COMPAT_SAMSUNG_EXYNOS5_I2C,	/* Exynos5 High Speed I2C Controller */
142 	COMPAT_SAMSUNG_EXYNOS_SYSMMU,	/* Exynos sysmmu */
143 	COMPAT_INTEL_MICROCODE,		/* Intel microcode update */
144 	COMPAT_AMS_AS3722,		/* AMS AS3722 PMIC */
145 	COMPAT_INTEL_QRK_MRC,		/* Intel Quark MRC */
146 	COMPAT_ALTERA_SOCFPGA_DWMAC,	/* SoCFPGA Ethernet controller */
147 	COMPAT_ALTERA_SOCFPGA_DWMMC,	/* SoCFPGA DWMMC controller */
148 	COMPAT_ALTERA_SOCFPGA_DWC2USB,	/* SoCFPGA DWC2 USB controller */
149 	COMPAT_INTEL_BAYTRAIL_FSP,	/* Intel Bay Trail FSP */
150 	COMPAT_INTEL_BAYTRAIL_FSP_MDP,	/* Intel FSP memory-down params */
151 	COMPAT_INTEL_IVYBRIDGE_FSP,	/* Intel Ivy Bridge FSP */
152 	COMPAT_SUNXI_NAND,		/* SUNXI NAND controller */
153 	COMPAT_ALTERA_SOCFPGA_CLK,	/* SoCFPGA Clock initialization */
154 	COMPAT_ALTERA_SOCFPGA_PINCTRL_SINGLE,	/* SoCFPGA pinctrl-single */
155 	COMPAT_ALTERA_SOCFPGA_H2F_BRG,          /* SoCFPGA hps2fpga bridge */
156 	COMPAT_ALTERA_SOCFPGA_LWH2F_BRG,        /* SoCFPGA lwhps2fpga bridge */
157 	COMPAT_ALTERA_SOCFPGA_F2H_BRG,          /* SoCFPGA fpga2hps bridge */
158 	COMPAT_ALTERA_SOCFPGA_F2SDR0,           /* SoCFPGA fpga2SDRAM0 bridge */
159 	COMPAT_ALTERA_SOCFPGA_F2SDR1,           /* SoCFPGA fpga2SDRAM1 bridge */
160 	COMPAT_ALTERA_SOCFPGA_F2SDR2,           /* SoCFPGA fpga2SDRAM2 bridge */
161 	COMPAT_ALTERA_SOCFPGA_FPGA0,		/* SOCFPGA FPGA manager */
162 	COMPAT_ALTERA_SOCFPGA_NOC,		/* SOCFPGA Arria 10 NOC */
163 
164 	COMPAT_COUNT,
165 };
166 
167 #define MAX_PHANDLE_ARGS 16
168 struct fdtdec_phandle_args {
169 	int node;
170 	int args_count;
171 	uint32_t args[MAX_PHANDLE_ARGS];
172 };
173 
174 /**
175  * fdtdec_parse_phandle_with_args() - Find a node pointed by phandle in a list
176  *
177  * This function is useful to parse lists of phandles and their arguments.
178  *
179  * Example:
180  *
181  * phandle1: node1 {
182  *	#list-cells = <2>;
183  * }
184  *
185  * phandle2: node2 {
186  *	#list-cells = <1>;
187  * }
188  *
189  * node3 {
190  *	list = <&phandle1 1 2 &phandle2 3>;
191  * }
192  *
193  * To get a device_node of the `node2' node you may call this:
194  * fdtdec_parse_phandle_with_args(blob, node3, "list", "#list-cells", 0, 1,
195  *				  &args);
196  *
197  * (This function is a modified version of __of_parse_phandle_with_args() from
198  * Linux 3.18)
199  *
200  * @blob:	Pointer to device tree
201  * @src_node:	Offset of device tree node containing a list
202  * @list_name:	property name that contains a list
203  * @cells_name:	property name that specifies the phandles' arguments count,
204  *		or NULL to use @cells_count
205  * @cells_count: Cell count to use if @cells_name is NULL
206  * @index:	index of a phandle to parse out
207  * @out_args:	optional pointer to output arguments structure (will be filled)
208  * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
209  *	@list_name does not exist, a phandle was not found, @cells_name
210  *	could not be found, the arguments were truncated or there were too
211  *	many arguments.
212  *
213  */
214 int fdtdec_parse_phandle_with_args(const void *blob, int src_node,
215 				   const char *list_name,
216 				   const char *cells_name,
217 				   int cell_count, int index,
218 				   struct fdtdec_phandle_args *out_args);
219 
220 /**
221  * Find the next numbered alias for a peripheral. This is used to enumerate
222  * all the peripherals of a certain type.
223  *
224  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
225  * this function will return a pointer to the node the alias points to, and
226  * then update *upto to 1. Next time you call this function, the next node
227  * will be returned.
228  *
229  * All nodes returned will match the compatible ID, as it is assumed that
230  * all peripherals use the same driver.
231  *
232  * @param blob		FDT blob to use
233  * @param name		Root name of alias to search for
234  * @param id		Compatible ID to look for
235  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
236  */
237 int fdtdec_next_alias(const void *blob, const char *name,
238 		enum fdt_compat_id id, int *upto);
239 
240 /**
241  * Find the compatible ID for a given node.
242  *
243  * Generally each node has at least one compatible string attached to it.
244  * This function looks through our list of known compatible strings and
245  * returns the corresponding ID which matches the compatible string.
246  *
247  * @param blob		FDT blob to use
248  * @param node		Node containing compatible string to find
249  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
250  */
251 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
252 
253 /**
254  * Find the next compatible node for a peripheral.
255  *
256  * Do the first call with node = 0. This function will return a pointer to
257  * the next compatible node. Next time you call this function, pass the
258  * value returned, and the next node will be provided.
259  *
260  * @param blob		FDT blob to use
261  * @param node		Start node for search
262  * @param id		Compatible ID to look for (enum fdt_compat_id)
263  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
264  */
265 int fdtdec_next_compatible(const void *blob, int node,
266 		enum fdt_compat_id id);
267 
268 /**
269  * Find the next compatible subnode for a peripheral.
270  *
271  * Do the first call with node set to the parent and depth = 0. This
272  * function will return the offset of the next compatible node. Next time
273  * you call this function, pass the node value returned last time, with
274  * depth unchanged, and the next node will be provided.
275  *
276  * @param blob		FDT blob to use
277  * @param node		Start node for search
278  * @param id		Compatible ID to look for (enum fdt_compat_id)
279  * @param depthp	Current depth (set to 0 before first call)
280  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
281  */
282 int fdtdec_next_compatible_subnode(const void *blob, int node,
283 		enum fdt_compat_id id, int *depthp);
284 
285 /*
286  * Look up an address property in a node and return the parsed address, and
287  * optionally the parsed size.
288  *
289  * This variant assumes a known and fixed number of cells are used to
290  * represent the address and size.
291  *
292  * You probably don't want to use this function directly except to parse
293  * non-standard properties, and never to parse the "reg" property. Instead,
294  * use one of the "auto" variants below, which automatically honor the
295  * #address-cells and #size-cells properties in the parent node.
296  *
297  * @param blob	FDT blob
298  * @param node	node to examine
299  * @param prop_name	name of property to find
300  * @param index	which address to retrieve from a list of addresses. Often 0.
301  * @param na	the number of cells used to represent an address
302  * @param ns	the number of cells used to represent a size
303  * @param sizep	a pointer to store the size into. Use NULL if not required
304  * @param translate	Indicates whether to translate the returned value
305  *			using the parent node's ranges property.
306  * @return address, if found, or FDT_ADDR_T_NONE if not
307  */
308 fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
309 		const char *prop_name, int index, int na, int ns,
310 		fdt_size_t *sizep, bool translate);
311 
312 /*
313  * Look up an address property in a node and return the parsed address, and
314  * optionally the parsed size.
315  *
316  * This variant automatically determines the number of cells used to represent
317  * the address and size by parsing the provided parent node's #address-cells
318  * and #size-cells properties.
319  *
320  * @param blob	FDT blob
321  * @param parent	parent node of @node
322  * @param node	node to examine
323  * @param prop_name	name of property to find
324  * @param index	which address to retrieve from a list of addresses. Often 0.
325  * @param sizep	a pointer to store the size into. Use NULL if not required
326  * @param translate	Indicates whether to translate the returned value
327  *			using the parent node's ranges property.
328  * @return address, if found, or FDT_ADDR_T_NONE if not
329  */
330 fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
331 		int node, const char *prop_name, int index, fdt_size_t *sizep,
332 		bool translate);
333 
334 /*
335  * Look up an address property in a node and return the parsed address, and
336  * optionally the parsed size.
337  *
338  * This variant automatically determines the number of cells used to represent
339  * the address and size by parsing the parent node's #address-cells
340  * and #size-cells properties. The parent node is automatically found.
341  *
342  * The automatic parent lookup implemented by this function is slow.
343  * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
344  * possible.
345  *
346  * @param blob	FDT blob
347  * @param parent	parent node of @node
348  * @param node	node to examine
349  * @param prop_name	name of property to find
350  * @param index	which address to retrieve from a list of addresses. Often 0.
351  * @param sizep	a pointer to store the size into. Use NULL if not required
352  * @param translate	Indicates whether to translate the returned value
353  *			using the parent node's ranges property.
354  * @return address, if found, or FDT_ADDR_T_NONE if not
355  */
356 fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
357 		const char *prop_name, int index, fdt_size_t *sizep,
358 		bool translate);
359 
360 /*
361  * Look up an address property in a node and return the parsed address.
362  *
363  * This variant hard-codes the number of cells used to represent the address
364  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
365  * always returns the first address value in the property (index 0).
366  *
367  * Use of this function is not recommended due to the hard-coding of cell
368  * counts. There is no programmatic validation that these hard-coded values
369  * actually match the device tree content in any way at all. This assumption
370  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
371  * set in the U-Boot build and exercising strict control over DT content to
372  * ensure use of matching #address-cells/#size-cells properties. However, this
373  * approach is error-prone; those familiar with DT will not expect the
374  * assumption to exist, and could easily invalidate it. If the assumption is
375  * invalidated, this function will not report the issue, and debugging will
376  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
377  *
378  * @param blob	FDT blob
379  * @param node	node to examine
380  * @param prop_name	name of property to find
381  * @return address, if found, or FDT_ADDR_T_NONE if not
382  */
383 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
384 		const char *prop_name);
385 
386 /*
387  * Look up an address property in a node and return the parsed address, and
388  * optionally the parsed size.
389  *
390  * This variant hard-codes the number of cells used to represent the address
391  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
392  * always returns the first address value in the property (index 0).
393  *
394  * Use of this function is not recommended due to the hard-coding of cell
395  * counts. There is no programmatic validation that these hard-coded values
396  * actually match the device tree content in any way at all. This assumption
397  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
398  * set in the U-Boot build and exercising strict control over DT content to
399  * ensure use of matching #address-cells/#size-cells properties. However, this
400  * approach is error-prone; those familiar with DT will not expect the
401  * assumption to exist, and could easily invalidate it. If the assumption is
402  * invalidated, this function will not report the issue, and debugging will
403  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
404  *
405  * @param blob	FDT blob
406  * @param node	node to examine
407  * @param prop_name	name of property to find
408  * @param sizep	a pointer to store the size into. Use NULL if not required
409  * @return address, if found, or FDT_ADDR_T_NONE if not
410  */
411 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
412 		const char *prop_name, fdt_size_t *sizep);
413 
414 /**
415  * Look at an address property in a node and return the pci address which
416  * corresponds to the given type in the form of fdt_pci_addr.
417  * The property must hold one fdt_pci_addr with a lengh.
418  *
419  * @param blob		FDT blob
420  * @param node		node to examine
421  * @param type		pci address type (FDT_PCI_SPACE_xxx)
422  * @param prop_name	name of property to find
423  * @param addr		returns pci address in the form of fdt_pci_addr
424  * @return 0 if ok, -ENOENT if the property did not exist, -EINVAL if the
425  *		format of the property was invalid, -ENXIO if the requested
426  *		address type was not found
427  */
428 int fdtdec_get_pci_addr(const void *blob, int node, enum fdt_pci_space type,
429 		const char *prop_name, struct fdt_pci_addr *addr);
430 
431 /**
432  * Look at the compatible property of a device node that represents a PCI
433  * device and extract pci vendor id and device id from it.
434  *
435  * @param blob		FDT blob
436  * @param node		node to examine
437  * @param vendor	vendor id of the pci device
438  * @param device	device id of the pci device
439  * @return 0 if ok, negative on error
440  */
441 int fdtdec_get_pci_vendev(const void *blob, int node,
442 		u16 *vendor, u16 *device);
443 
444 /**
445  * Look at the pci address of a device node that represents a PCI device
446  * and return base address of the pci device's registers.
447  *
448  * @param dev		device to examine
449  * @param addr		pci address in the form of fdt_pci_addr
450  * @param bar		returns base address of the pci device's registers
451  * @return 0 if ok, negative on error
452  */
453 int fdtdec_get_pci_bar32(struct udevice *dev, struct fdt_pci_addr *addr,
454 			 u32 *bar);
455 
456 /**
457  * Look up a 32-bit integer property in a node and return it. The property
458  * must have at least 4 bytes of data. The value of the first cell is
459  * returned.
460  *
461  * @param blob	FDT blob
462  * @param node	node to examine
463  * @param prop_name	name of property to find
464  * @param default_val	default value to return if the property is not found
465  * @return integer value, if found, or default_val if not
466  */
467 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
468 		s32 default_val);
469 
470 /**
471  * Unsigned version of fdtdec_get_int. The property must have at least
472  * 4 bytes of data. The value of the first cell is returned.
473  *
474  * @param blob	FDT blob
475  * @param node	node to examine
476  * @param prop_name	name of property to find
477  * @param default_val	default value to return if the property is not found
478  * @return unsigned integer value, if found, or default_val if not
479  */
480 unsigned int fdtdec_get_uint(const void *blob, int node, const char *prop_name,
481 			unsigned int default_val);
482 
483 /**
484  * Get a variable-sized number from a property
485  *
486  * This reads a number from one or more cells.
487  *
488  * @param ptr	Pointer to property
489  * @param cells	Number of cells containing the number
490  * @return the value in the cells
491  */
492 u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells);
493 
494 /**
495  * Look up a 64-bit integer property in a node and return it. The property
496  * must have at least 8 bytes of data (2 cells). The first two cells are
497  * concatenated to form a 8 bytes value, where the first cell is top half and
498  * the second cell is bottom half.
499  *
500  * @param blob	FDT blob
501  * @param node	node to examine
502  * @param prop_name	name of property to find
503  * @param default_val	default value to return if the property is not found
504  * @return integer value, if found, or default_val if not
505  */
506 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
507 		uint64_t default_val);
508 
509 /**
510  * Checks whether a node is enabled.
511  * This looks for a 'status' property. If this exists, then returns 1 if
512  * the status is 'ok' and 0 otherwise. If there is no status property,
513  * it returns 1 on the assumption that anything mentioned should be enabled
514  * by default.
515  *
516  * @param blob	FDT blob
517  * @param node	node to examine
518  * @return integer value 0 (not enabled) or 1 (enabled)
519  */
520 int fdtdec_get_is_enabled(const void *blob, int node);
521 
522 /**
523  * Make sure we have a valid fdt available to control U-Boot.
524  *
525  * If not, a message is printed to the console if the console is ready.
526  *
527  * @return 0 if all ok, -1 if not
528  */
529 int fdtdec_prepare_fdt(void);
530 
531 /**
532  * Checks that we have a valid fdt available to control U-Boot.
533 
534  * However, if not then for the moment nothing is done, since this function
535  * is called too early to panic().
536  *
537  * @returns 0
538  */
539 int fdtdec_check_fdt(void);
540 
541 /**
542  * Find the nodes for a peripheral and return a list of them in the correct
543  * order. This is used to enumerate all the peripherals of a certain type.
544  *
545  * To use this, optionally set up a /aliases node with alias properties for
546  * a peripheral. For example, for usb you could have:
547  *
548  * aliases {
549  *		usb0 = "/ehci@c5008000";
550  *		usb1 = "/ehci@c5000000";
551  * };
552  *
553  * Pass "usb" as the name to this function and will return a list of two
554  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
555  *
556  * All nodes returned will match the compatible ID, as it is assumed that
557  * all peripherals use the same driver.
558  *
559  * If no alias node is found, then the node list will be returned in the
560  * order found in the fdt. If the aliases mention a node which doesn't
561  * exist, then this will be ignored. If nodes are found with no aliases,
562  * they will be added in any order.
563  *
564  * If there is a gap in the aliases, then this function return a 0 node at
565  * that position. The return value will also count these gaps.
566  *
567  * This function checks node properties and will not return nodes which are
568  * marked disabled (status = "disabled").
569  *
570  * @param blob		FDT blob to use
571  * @param name		Root name of alias to search for
572  * @param id		Compatible ID to look for
573  * @param node_list	Place to put list of found nodes
574  * @param maxcount	Maximum number of nodes to find
575  * @return number of nodes found on success, FDT_ERR_... on error
576  */
577 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
578 			enum fdt_compat_id id, int *node_list, int maxcount);
579 
580 /*
581  * This function is similar to fdtdec_find_aliases_for_id() except that it
582  * adds to the node_list that is passed in. Any 0 elements are considered
583  * available for allocation - others are considered already used and are
584  * skipped.
585  *
586  * You can use this by calling fdtdec_find_aliases_for_id() with an
587  * uninitialised array, then setting the elements that are returned to -1,
588  * say, then calling this function, perhaps with a different compat id.
589  * Any elements you get back that are >0 are new nodes added by the call
590  * to this function.
591  *
592  * Note that if you have some nodes with aliases and some without, you are
593  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
594  * one compat_id may fill in positions for which you have aliases defined
595  * for another compat_id. When you later call *this* function with the second
596  * compat_id, the alias positions may already be used. A debug warning may
597  * be generated in this case, but it is safest to define aliases for all
598  * nodes when you care about the ordering.
599  */
600 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
601 			enum fdt_compat_id id, int *node_list, int maxcount);
602 
603 /**
604  * Get the alias sequence number of a node
605  *
606  * This works out whether a node is pointed to by an alias, and if so, the
607  * sequence number of that alias. Aliases are of the form <base><num> where
608  * <num> is the sequence number. For example spi2 would be sequence number
609  * 2.
610  *
611  * @param blob		Device tree blob (if NULL, then error is returned)
612  * @param base		Base name for alias (before the underscore)
613  * @param node		Node to look up
614  * @param seqp		This is set to the sequence number if one is found,
615  *			but otherwise the value is left alone
616  * @return 0 if a sequence was found, -ve if not
617  */
618 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
619 			 int *seqp);
620 
621 /**
622  * Get a property from the /chosen node
623  *
624  * @param blob		Device tree blob (if NULL, then NULL is returned)
625  * @param name		Property name to look up
626  * @return Value of property, or NULL if it does not exist
627  */
628 const char *fdtdec_get_chosen_prop(const void *blob, const char *name);
629 
630 /**
631  * Get the offset of the given /chosen node
632  *
633  * This looks up a property in /chosen containing the path to another node,
634  * then finds the offset of that node.
635  *
636  * @param blob		Device tree blob (if NULL, then error is returned)
637  * @param name		Property name, e.g. "stdout-path"
638  * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
639  */
640 int fdtdec_get_chosen_node(const void *blob, const char *name);
641 
642 /*
643  * Get the name for a compatible ID
644  *
645  * @param id		Compatible ID to look for
646  * @return compatible string for that id
647  */
648 const char *fdtdec_get_compatible(enum fdt_compat_id id);
649 
650 /* Look up a phandle and follow it to its node. Then return the offset
651  * of that node.
652  *
653  * @param blob		FDT blob
654  * @param node		node to examine
655  * @param prop_name	name of property to find
656  * @return node offset if found, -ve error code on error
657  */
658 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
659 
660 /**
661  * Look up a property in a node and return its contents in an integer
662  * array of given length. The property must have at least enough data for
663  * the array (4*count bytes). It may have more, but this will be ignored.
664  *
665  * @param blob		FDT blob
666  * @param node		node to examine
667  * @param prop_name	name of property to find
668  * @param array		array to fill with data
669  * @param count		number of array elements
670  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
671  *		or -FDT_ERR_BADLAYOUT if not enough data
672  */
673 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
674 		u32 *array, int count);
675 
676 /**
677  * Look up a property in a node and return its contents in an integer
678  * array of given length. The property must exist but may have less data that
679  * expected (4*count bytes). It may have more, but this will be ignored.
680  *
681  * @param blob		FDT blob
682  * @param node		node to examine
683  * @param prop_name	name of property to find
684  * @param array		array to fill with data
685  * @param count		number of array elements
686  * @return number of array elements if ok, or -FDT_ERR_NOTFOUND if the
687  *		property is not found
688  */
689 int fdtdec_get_int_array_count(const void *blob, int node,
690 			       const char *prop_name, u32 *array, int count);
691 
692 /**
693  * Look up a property in a node and return a pointer to its contents as a
694  * unsigned int array of given length. The property must have at least enough
695  * data for the array ('count' cells). It may have more, but this will be
696  * ignored. The data is not copied.
697  *
698  * Note that you must access elements of the array with fdt32_to_cpu(),
699  * since the elements will be big endian even on a little endian machine.
700  *
701  * @param blob		FDT blob
702  * @param node		node to examine
703  * @param prop_name	name of property to find
704  * @param count		number of array elements
705  * @return pointer to array if found, or NULL if the property is not
706  *		found or there is not enough data
707  */
708 const u32 *fdtdec_locate_array(const void *blob, int node,
709 			       const char *prop_name, int count);
710 
711 /**
712  * Look up a boolean property in a node and return it.
713  *
714  * A boolean properly is true if present in the device tree and false if not
715  * present, regardless of its value.
716  *
717  * @param blob	FDT blob
718  * @param node	node to examine
719  * @param prop_name	name of property to find
720  * @return 1 if the properly is present; 0 if it isn't present
721  */
722 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
723 
724 /*
725  * Count child nodes of one parent node.
726  *
727  * @param blob	FDT blob
728  * @param node	parent node
729  * @return number of child node; 0 if there is not child node
730  */
731 int fdtdec_get_child_count(const void *blob, int node);
732 
733 /**
734  * Look in the FDT for a config item with the given name and return its value
735  * as a 32-bit integer. The property must have at least 4 bytes of data. The
736  * value of the first cell is returned.
737  *
738  * @param blob		FDT blob to use
739  * @param prop_name	Node property name
740  * @param default_val	default value to return if the property is not found
741  * @return integer value, if found, or default_val if not
742  */
743 int fdtdec_get_config_int(const void *blob, const char *prop_name,
744 		int default_val);
745 
746 /**
747  * Look in the FDT for a config item with the given name
748  * and return whether it exists.
749  *
750  * @param blob		FDT blob
751  * @param prop_name	property name to look up
752  * @return 1, if it exists, or 0 if not
753  */
754 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
755 
756 /**
757  * Look in the FDT for a config item with the given name and return its value
758  * as a string.
759  *
760  * @param blob          FDT blob
761  * @param prop_name     property name to look up
762  * @returns property string, NULL on error.
763  */
764 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
765 
766 /*
767  * Look up a property in a node and return its contents in a byte
768  * array of given length. The property must have at least enough data for
769  * the array (count bytes). It may have more, but this will be ignored.
770  *
771  * @param blob		FDT blob
772  * @param node		node to examine
773  * @param prop_name	name of property to find
774  * @param array		array to fill with data
775  * @param count		number of array elements
776  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
777  *		or -FDT_ERR_BADLAYOUT if not enough data
778  */
779 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
780 		u8 *array, int count);
781 
782 /**
783  * Look up a property in a node and return a pointer to its contents as a
784  * byte array of given length. The property must have at least enough data
785  * for the array (count bytes). It may have more, but this will be ignored.
786  * The data is not copied.
787  *
788  * @param blob		FDT blob
789  * @param node		node to examine
790  * @param prop_name	name of property to find
791  * @param count		number of array elements
792  * @return pointer to byte array if found, or NULL if the property is not
793  *		found or there is not enough data
794  */
795 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
796 			     const char *prop_name, int count);
797 
798 /**
799  * Look up a property in a node which contains a memory region address and
800  * size. Then return a pointer to this address.
801  *
802  * The property must hold one address with a length. This is only tested on
803  * 32-bit machines.
804  *
805  * @param blob		FDT blob
806  * @param node		node to examine
807  * @param prop_name	name of property to find
808  * @param basep		Returns base address of region
809  * @param size		Returns size of region
810  * @return 0 if ok, -1 on error (property not found)
811  */
812 int fdtdec_decode_region(const void *blob, int node, const char *prop_name,
813 			 fdt_addr_t *basep, fdt_size_t *sizep);
814 
815 /**
816  * Obtain an indexed resource from a device property.
817  *
818  * @param fdt		FDT blob
819  * @param node		node to examine
820  * @param property	name of the property to parse
821  * @param index		index of the resource to retrieve
822  * @param res		returns the resource
823  * @return 0 if ok, negative on error
824  */
825 int fdt_get_resource(const void *fdt, int node, const char *property,
826 		     unsigned int index, struct fdt_resource *res);
827 
828 /**
829  * Obtain a named resource from a device property.
830  *
831  * Look up the index of the name in a list of strings and return the resource
832  * at that index.
833  *
834  * @param fdt		FDT blob
835  * @param node		node to examine
836  * @param property	name of the property to parse
837  * @param prop_names	name of the property containing the list of names
838  * @param name		the name of the entry to look up
839  * @param res		returns the resource
840  */
841 int fdt_get_named_resource(const void *fdt, int node, const char *property,
842 			   const char *prop_names, const char *name,
843 			   struct fdt_resource *res);
844 
845 /**
846  * Decode a named region within a memory bank of a given type.
847  *
848  * This function handles selection of a memory region. The region is
849  * specified as an offset/size within a particular type of memory.
850  *
851  * The properties used are:
852  *
853  *	<mem_type>-memory<suffix> for the name of the memory bank
854  *	<mem_type>-offset<suffix> for the offset in that bank
855  *
856  * The property value must have an offset and a size. The function checks
857  * that the region is entirely within the memory bank.5
858  *
859  * @param blob		FDT blob
860  * @param node		Node containing the properties (-1 for /config)
861  * @param mem_type	Type of memory to use, which is a name, such as
862  *			"u-boot" or "kernel".
863  * @param suffix	String to append to the memory/offset
864  *			property names
865  * @param basep		Returns base of region
866  * @param sizep		Returns size of region
867  * @return 0 if OK, -ive on error
868  */
869 int fdtdec_decode_memory_region(const void *blob, int node,
870 				const char *mem_type, const char *suffix,
871 				fdt_addr_t *basep, fdt_size_t *sizep);
872 
873 /* Display timings from linux include/video/display_timing.h */
874 enum display_flags {
875 	DISPLAY_FLAGS_HSYNC_LOW		= 1 << 0,
876 	DISPLAY_FLAGS_HSYNC_HIGH	= 1 << 1,
877 	DISPLAY_FLAGS_VSYNC_LOW		= 1 << 2,
878 	DISPLAY_FLAGS_VSYNC_HIGH	= 1 << 3,
879 
880 	/* data enable flag */
881 	DISPLAY_FLAGS_DE_LOW		= 1 << 4,
882 	DISPLAY_FLAGS_DE_HIGH		= 1 << 5,
883 	/* drive data on pos. edge */
884 	DISPLAY_FLAGS_PIXDATA_POSEDGE	= 1 << 6,
885 	/* drive data on neg. edge */
886 	DISPLAY_FLAGS_PIXDATA_NEGEDGE	= 1 << 7,
887 	DISPLAY_FLAGS_INTERLACED	= 1 << 8,
888 	DISPLAY_FLAGS_DOUBLESCAN	= 1 << 9,
889 	DISPLAY_FLAGS_DOUBLECLK		= 1 << 10,
890 };
891 
892 /*
893  * A single signal can be specified via a range of minimal and maximal values
894  * with a typical value, that lies somewhere inbetween.
895  */
896 struct timing_entry {
897 	u32 min;
898 	u32 typ;
899 	u32 max;
900 };
901 
902 /*
903  * Single "mode" entry. This describes one set of signal timings a display can
904  * have in one setting. This struct can later be converted to struct videomode
905  * (see include/video/videomode.h). As each timing_entry can be defined as a
906  * range, one struct display_timing may become multiple struct videomodes.
907  *
908  * Example: hsync active high, vsync active low
909  *
910  *				    Active Video
911  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
912  *	  |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
913  *	  |	     |	 porch  |		     |	 porch	 |
914  *
915  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
916  *
917  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
918  */
919 struct display_timing {
920 	struct timing_entry pixelclock;
921 
922 	struct timing_entry hactive;		/* hor. active video */
923 	struct timing_entry hfront_porch;	/* hor. front porch */
924 	struct timing_entry hback_porch;	/* hor. back porch */
925 	struct timing_entry hsync_len;		/* hor. sync len */
926 
927 	struct timing_entry vactive;		/* ver. active video */
928 	struct timing_entry vfront_porch;	/* ver. front porch */
929 	struct timing_entry vback_porch;	/* ver. back porch */
930 	struct timing_entry vsync_len;		/* ver. sync len */
931 
932 	enum display_flags flags;		/* display flags */
933 	bool hdmi_monitor;			/* is hdmi monitor? */
934 };
935 
936 /**
937  * fdtdec_decode_display_timing() - decode display timings
938  *
939  * Decode display timings from the supplied 'display-timings' node.
940  * See doc/device-tree-bindings/video/display-timing.txt for binding
941  * information.
942  *
943  * @param blob		FDT blob
944  * @param node		'display-timing' node containing the timing subnodes
945  * @param index		Index number to read (0=first timing subnode)
946  * @param config	Place to put timings
947  * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
948  */
949 int fdtdec_decode_display_timing(const void *blob, int node, int index,
950 				 struct display_timing *config);
951 
952 /**
953  * fdtdec_setup_memory_size() - decode and setup gd->ram_size
954  *
955  * Decode the /memory 'reg' property to determine the size of the first memory
956  * bank, populate the global data with the size of the first bank of memory.
957  *
958  * This function should be called from a boards dram_init(). This helper
959  * function allows for boards to query the device tree for DRAM size instead of
960  * hard coding the value in the case where the memory size cannot be detected
961  * automatically.
962  *
963  * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
964  * invalid
965  */
966 int fdtdec_setup_memory_size(void);
967 
968 /**
969  * fdtdec_setup_memory_banksize() - decode and populate gd->bd->bi_dram
970  *
971  * Decode the /memory 'reg' property to determine the address and size of the
972  * memory banks. Use this data to populate the global data board info with the
973  * phys address and size of memory banks.
974  *
975  * This function should be called from a boards dram_init_banksize(). This
976  * helper function allows for boards to query the device tree for memory bank
977  * information instead of hard coding the information in cases where it cannot
978  * be detected automatically.
979  *
980  * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
981  * invalid
982  */
983 int fdtdec_setup_memory_banksize(void);
984 
985 /**
986  * Set up the device tree ready for use
987  */
988 int fdtdec_setup(void);
989 
990 /**
991  * Board-specific FDT initialization. Returns the address to a device tree blob.
992  * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
993  * and the board implements it.
994  */
995 void *board_fdt_blob_setup(void);
996 
997 #endif
998