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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  */
fdt_resource_size(const struct fdt_resource * res)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 	COMPAT_ALTERA_SOCFPGA_CLK_INIT,		/* SOCFPGA Arria 10 clk init */
164 
165 	COMPAT_COUNT,
166 };
167 
168 #define MAX_PHANDLE_ARGS 16
169 struct fdtdec_phandle_args {
170 	int node;
171 	int args_count;
172 	uint32_t args[MAX_PHANDLE_ARGS];
173 };
174 
175 /**
176  * fdtdec_parse_phandle_with_args() - Find a node pointed by phandle in a list
177  *
178  * This function is useful to parse lists of phandles and their arguments.
179  *
180  * Example:
181  *
182  * phandle1: node1 {
183  *	#list-cells = <2>;
184  * }
185  *
186  * phandle2: node2 {
187  *	#list-cells = <1>;
188  * }
189  *
190  * node3 {
191  *	list = <&phandle1 1 2 &phandle2 3>;
192  * }
193  *
194  * To get a device_node of the `node2' node you may call this:
195  * fdtdec_parse_phandle_with_args(blob, node3, "list", "#list-cells", 0, 1,
196  *				  &args);
197  *
198  * (This function is a modified version of __of_parse_phandle_with_args() from
199  * Linux 3.18)
200  *
201  * @blob:	Pointer to device tree
202  * @src_node:	Offset of device tree node containing a list
203  * @list_name:	property name that contains a list
204  * @cells_name:	property name that specifies the phandles' arguments count,
205  *		or NULL to use @cells_count
206  * @cells_count: Cell count to use if @cells_name is NULL
207  * @index:	index of a phandle to parse out
208  * @out_args:	optional pointer to output arguments structure (will be filled)
209  * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
210  *	@list_name does not exist, a phandle was not found, @cells_name
211  *	could not be found, the arguments were truncated or there were too
212  *	many arguments.
213  *
214  */
215 int fdtdec_parse_phandle_with_args(const void *blob, int src_node,
216 				   const char *list_name,
217 				   const char *cells_name,
218 				   int cell_count, int index,
219 				   struct fdtdec_phandle_args *out_args);
220 
221 /**
222  * Find the next numbered alias for a peripheral. This is used to enumerate
223  * all the peripherals of a certain type.
224  *
225  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
226  * this function will return a pointer to the node the alias points to, and
227  * then update *upto to 1. Next time you call this function, the next node
228  * will be returned.
229  *
230  * All nodes returned will match the compatible ID, as it is assumed that
231  * all peripherals use the same driver.
232  *
233  * @param blob		FDT blob to use
234  * @param name		Root name of alias to search for
235  * @param id		Compatible ID to look for
236  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
237  */
238 int fdtdec_next_alias(const void *blob, const char *name,
239 		enum fdt_compat_id id, int *upto);
240 
241 /**
242  * Find the compatible ID for a given node.
243  *
244  * Generally each node has at least one compatible string attached to it.
245  * This function looks through our list of known compatible strings and
246  * returns the corresponding ID which matches the compatible string.
247  *
248  * @param blob		FDT blob to use
249  * @param node		Node containing compatible string to find
250  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
251  */
252 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
253 
254 /**
255  * Find the next compatible node for a peripheral.
256  *
257  * Do the first call with node = 0. This function will return a pointer to
258  * the next compatible node. Next time you call this function, pass the
259  * value returned, and the next node will be provided.
260  *
261  * @param blob		FDT blob to use
262  * @param node		Start node for search
263  * @param id		Compatible ID to look for (enum fdt_compat_id)
264  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
265  */
266 int fdtdec_next_compatible(const void *blob, int node,
267 		enum fdt_compat_id id);
268 
269 /**
270  * Find the next compatible subnode for a peripheral.
271  *
272  * Do the first call with node set to the parent and depth = 0. This
273  * function will return the offset of the next compatible node. Next time
274  * you call this function, pass the node value returned last time, with
275  * depth unchanged, and the next node will be provided.
276  *
277  * @param blob		FDT blob to use
278  * @param node		Start node for search
279  * @param id		Compatible ID to look for (enum fdt_compat_id)
280  * @param depthp	Current depth (set to 0 before first call)
281  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
282  */
283 int fdtdec_next_compatible_subnode(const void *blob, int node,
284 		enum fdt_compat_id id, int *depthp);
285 
286 /*
287  * Look up an address property in a node and return the parsed address, and
288  * optionally the parsed size.
289  *
290  * This variant assumes a known and fixed number of cells are used to
291  * represent the address and size.
292  *
293  * You probably don't want to use this function directly except to parse
294  * non-standard properties, and never to parse the "reg" property. Instead,
295  * use one of the "auto" variants below, which automatically honor the
296  * #address-cells and #size-cells properties in the parent node.
297  *
298  * @param blob	FDT blob
299  * @param node	node to examine
300  * @param prop_name	name of property to find
301  * @param index	which address to retrieve from a list of addresses. Often 0.
302  * @param na	the number of cells used to represent an address
303  * @param ns	the number of cells used to represent a size
304  * @param sizep	a pointer to store the size into. Use NULL if not required
305  * @param translate	Indicates whether to translate the returned value
306  *			using the parent node's ranges property.
307  * @return address, if found, or FDT_ADDR_T_NONE if not
308  */
309 fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
310 		const char *prop_name, int index, int na, int ns,
311 		fdt_size_t *sizep, bool translate);
312 
313 /*
314  * Look up an address property in a node and return the parsed address, and
315  * optionally the parsed size.
316  *
317  * This variant automatically determines the number of cells used to represent
318  * the address and size by parsing the provided parent node's #address-cells
319  * and #size-cells properties.
320  *
321  * @param blob	FDT blob
322  * @param parent	parent node of @node
323  * @param node	node to examine
324  * @param prop_name	name of property to find
325  * @param index	which address to retrieve from a list of addresses. Often 0.
326  * @param sizep	a pointer to store the size into. Use NULL if not required
327  * @param translate	Indicates whether to translate the returned value
328  *			using the parent node's ranges property.
329  * @return address, if found, or FDT_ADDR_T_NONE if not
330  */
331 fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
332 		int node, const char *prop_name, int index, fdt_size_t *sizep,
333 		bool translate);
334 
335 /*
336  * Look up an address property in a node and return the parsed address, and
337  * optionally the parsed size.
338  *
339  * This variant automatically determines the number of cells used to represent
340  * the address and size by parsing the parent node's #address-cells
341  * and #size-cells properties. The parent node is automatically found.
342  *
343  * The automatic parent lookup implemented by this function is slow.
344  * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
345  * possible.
346  *
347  * @param blob	FDT blob
348  * @param parent	parent node of @node
349  * @param node	node to examine
350  * @param prop_name	name of property to find
351  * @param index	which address to retrieve from a list of addresses. Often 0.
352  * @param sizep	a pointer to store the size into. Use NULL if not required
353  * @param translate	Indicates whether to translate the returned value
354  *			using the parent node's ranges property.
355  * @return address, if found, or FDT_ADDR_T_NONE if not
356  */
357 fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
358 		const char *prop_name, int index, fdt_size_t *sizep,
359 		bool translate);
360 
361 /*
362  * Look up an address property in a node and return the parsed address.
363  *
364  * This variant hard-codes the number of cells used to represent the address
365  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
366  * always returns the first address value in the property (index 0).
367  *
368  * Use of this function is not recommended due to the hard-coding of cell
369  * counts. There is no programmatic validation that these hard-coded values
370  * actually match the device tree content in any way at all. This assumption
371  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
372  * set in the U-Boot build and exercising strict control over DT content to
373  * ensure use of matching #address-cells/#size-cells properties. However, this
374  * approach is error-prone; those familiar with DT will not expect the
375  * assumption to exist, and could easily invalidate it. If the assumption is
376  * invalidated, this function will not report the issue, and debugging will
377  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
378  *
379  * @param blob	FDT blob
380  * @param node	node to examine
381  * @param prop_name	name of property to find
382  * @return address, if found, or FDT_ADDR_T_NONE if not
383  */
384 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
385 		const char *prop_name);
386 
387 /*
388  * Look up an address property in a node and return the parsed address, and
389  * optionally the parsed size.
390  *
391  * This variant hard-codes the number of cells used to represent the address
392  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
393  * always returns the first address value in the property (index 0).
394  *
395  * Use of this function is not recommended due to the hard-coding of cell
396  * counts. There is no programmatic validation that these hard-coded values
397  * actually match the device tree content in any way at all. This assumption
398  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
399  * set in the U-Boot build and exercising strict control over DT content to
400  * ensure use of matching #address-cells/#size-cells properties. However, this
401  * approach is error-prone; those familiar with DT will not expect the
402  * assumption to exist, and could easily invalidate it. If the assumption is
403  * invalidated, this function will not report the issue, and debugging will
404  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
405  *
406  * @param blob	FDT blob
407  * @param node	node to examine
408  * @param prop_name	name of property to find
409  * @param sizep	a pointer to store the size into. Use NULL if not required
410  * @return address, if found, or FDT_ADDR_T_NONE if not
411  */
412 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
413 		const char *prop_name, fdt_size_t *sizep);
414 
415 /**
416  * Look at an address property in a node and return the pci address which
417  * corresponds to the given type in the form of fdt_pci_addr.
418  * The property must hold one fdt_pci_addr with a lengh.
419  *
420  * @param blob		FDT blob
421  * @param node		node to examine
422  * @param type		pci address type (FDT_PCI_SPACE_xxx)
423  * @param prop_name	name of property to find
424  * @param addr		returns pci address in the form of fdt_pci_addr
425  * @return 0 if ok, -ENOENT if the property did not exist, -EINVAL if the
426  *		format of the property was invalid, -ENXIO if the requested
427  *		address type was not found
428  */
429 int fdtdec_get_pci_addr(const void *blob, int node, enum fdt_pci_space type,
430 		const char *prop_name, struct fdt_pci_addr *addr);
431 
432 /**
433  * Look at the compatible property of a device node that represents a PCI
434  * device and extract pci vendor id and device id from it.
435  *
436  * @param blob		FDT blob
437  * @param node		node to examine
438  * @param vendor	vendor id of the pci device
439  * @param device	device id of the pci device
440  * @return 0 if ok, negative on error
441  */
442 int fdtdec_get_pci_vendev(const void *blob, int node,
443 		u16 *vendor, u16 *device);
444 
445 /**
446  * Look at the pci address of a device node that represents a PCI device
447  * and return base address of the pci device's registers.
448  *
449  * @param dev		device to examine
450  * @param addr		pci address in the form of fdt_pci_addr
451  * @param bar		returns base address of the pci device's registers
452  * @return 0 if ok, negative on error
453  */
454 int fdtdec_get_pci_bar32(struct udevice *dev, struct fdt_pci_addr *addr,
455 			 u32 *bar);
456 
457 /**
458  * Look up a 32-bit integer property in a node and return it. The property
459  * must have at least 4 bytes of data. The value of the first cell is
460  * returned.
461  *
462  * @param blob	FDT blob
463  * @param node	node to examine
464  * @param prop_name	name of property to find
465  * @param default_val	default value to return if the property is not found
466  * @return integer value, if found, or default_val if not
467  */
468 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
469 		s32 default_val);
470 
471 /**
472  * Unsigned version of fdtdec_get_int. The property must have at least
473  * 4 bytes of data. The value of the first cell is returned.
474  *
475  * @param blob	FDT blob
476  * @param node	node to examine
477  * @param prop_name	name of property to find
478  * @param default_val	default value to return if the property is not found
479  * @return unsigned integer value, if found, or default_val if not
480  */
481 unsigned int fdtdec_get_uint(const void *blob, int node, const char *prop_name,
482 			unsigned int default_val);
483 
484 /**
485  * Get a variable-sized number from a property
486  *
487  * This reads a number from one or more cells.
488  *
489  * @param ptr	Pointer to property
490  * @param cells	Number of cells containing the number
491  * @return the value in the cells
492  */
493 u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells);
494 
495 /**
496  * Look up a 64-bit integer property in a node and return it. The property
497  * must have at least 8 bytes of data (2 cells). The first two cells are
498  * concatenated to form a 8 bytes value, where the first cell is top half and
499  * the second cell is bottom half.
500  *
501  * @param blob	FDT blob
502  * @param node	node to examine
503  * @param prop_name	name of property to find
504  * @param default_val	default value to return if the property is not found
505  * @return integer value, if found, or default_val if not
506  */
507 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
508 		uint64_t default_val);
509 
510 /**
511  * Checks whether a node is enabled.
512  * This looks for a 'status' property. If this exists, then returns 1 if
513  * the status is 'ok' and 0 otherwise. If there is no status property,
514  * it returns 1 on the assumption that anything mentioned should be enabled
515  * by default.
516  *
517  * @param blob	FDT blob
518  * @param node	node to examine
519  * @return integer value 0 (not enabled) or 1 (enabled)
520  */
521 int fdtdec_get_is_enabled(const void *blob, int node);
522 
523 /**
524  * Make sure we have a valid fdt available to control U-Boot.
525  *
526  * If not, a message is printed to the console if the console is ready.
527  *
528  * @return 0 if all ok, -1 if not
529  */
530 int fdtdec_prepare_fdt(void);
531 
532 /**
533  * Checks that we have a valid fdt available to control U-Boot.
534 
535  * However, if not then for the moment nothing is done, since this function
536  * is called too early to panic().
537  *
538  * @returns 0
539  */
540 int fdtdec_check_fdt(void);
541 
542 /**
543  * Find the nodes for a peripheral and return a list of them in the correct
544  * order. This is used to enumerate all the peripherals of a certain type.
545  *
546  * To use this, optionally set up a /aliases node with alias properties for
547  * a peripheral. For example, for usb you could have:
548  *
549  * aliases {
550  *		usb0 = "/ehci@c5008000";
551  *		usb1 = "/ehci@c5000000";
552  * };
553  *
554  * Pass "usb" as the name to this function and will return a list of two
555  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
556  *
557  * All nodes returned will match the compatible ID, as it is assumed that
558  * all peripherals use the same driver.
559  *
560  * If no alias node is found, then the node list will be returned in the
561  * order found in the fdt. If the aliases mention a node which doesn't
562  * exist, then this will be ignored. If nodes are found with no aliases,
563  * they will be added in any order.
564  *
565  * If there is a gap in the aliases, then this function return a 0 node at
566  * that position. The return value will also count these gaps.
567  *
568  * This function checks node properties and will not return nodes which are
569  * marked disabled (status = "disabled").
570  *
571  * @param blob		FDT blob to use
572  * @param name		Root name of alias to search for
573  * @param id		Compatible ID to look for
574  * @param node_list	Place to put list of found nodes
575  * @param maxcount	Maximum number of nodes to find
576  * @return number of nodes found on success, FDT_ERR_... on error
577  */
578 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
579 			enum fdt_compat_id id, int *node_list, int maxcount);
580 
581 /*
582  * This function is similar to fdtdec_find_aliases_for_id() except that it
583  * adds to the node_list that is passed in. Any 0 elements are considered
584  * available for allocation - others are considered already used and are
585  * skipped.
586  *
587  * You can use this by calling fdtdec_find_aliases_for_id() with an
588  * uninitialised array, then setting the elements that are returned to -1,
589  * say, then calling this function, perhaps with a different compat id.
590  * Any elements you get back that are >0 are new nodes added by the call
591  * to this function.
592  *
593  * Note that if you have some nodes with aliases and some without, you are
594  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
595  * one compat_id may fill in positions for which you have aliases defined
596  * for another compat_id. When you later call *this* function with the second
597  * compat_id, the alias positions may already be used. A debug warning may
598  * be generated in this case, but it is safest to define aliases for all
599  * nodes when you care about the ordering.
600  */
601 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
602 			enum fdt_compat_id id, int *node_list, int maxcount);
603 
604 /**
605  * Get the alias sequence number of a node
606  *
607  * This works out whether a node is pointed to by an alias, and if so, the
608  * sequence number of that alias. Aliases are of the form <base><num> where
609  * <num> is the sequence number. For example spi2 would be sequence number
610  * 2.
611  *
612  * @param blob		Device tree blob (if NULL, then error is returned)
613  * @param base		Base name for alias (before the underscore)
614  * @param node		Node to look up
615  * @param seqp		This is set to the sequence number if one is found,
616  *			but otherwise the value is left alone
617  * @return 0 if a sequence was found, -ve if not
618  */
619 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
620 			 int *seqp);
621 
622 /**
623  * Get a property from the /chosen node
624  *
625  * @param blob		Device tree blob (if NULL, then NULL is returned)
626  * @param name		Property name to look up
627  * @return Value of property, or NULL if it does not exist
628  */
629 const char *fdtdec_get_chosen_prop(const void *blob, const char *name);
630 
631 /**
632  * Get the offset of the given /chosen node
633  *
634  * This looks up a property in /chosen containing the path to another node,
635  * then finds the offset of that node.
636  *
637  * @param blob		Device tree blob (if NULL, then error is returned)
638  * @param name		Property name, e.g. "stdout-path"
639  * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
640  */
641 int fdtdec_get_chosen_node(const void *blob, const char *name);
642 
643 /*
644  * Get the name for a compatible ID
645  *
646  * @param id		Compatible ID to look for
647  * @return compatible string for that id
648  */
649 const char *fdtdec_get_compatible(enum fdt_compat_id id);
650 
651 /* Look up a phandle and follow it to its node. Then return the offset
652  * of that node.
653  *
654  * @param blob		FDT blob
655  * @param node		node to examine
656  * @param prop_name	name of property to find
657  * @return node offset if found, -ve error code on error
658  */
659 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
660 
661 /**
662  * Look up a property in a node and return its contents in an integer
663  * array of given length. The property must have at least enough data for
664  * the array (4*count bytes). It may have more, but this will be ignored.
665  *
666  * @param blob		FDT blob
667  * @param node		node to examine
668  * @param prop_name	name of property to find
669  * @param array		array to fill with data
670  * @param count		number of array elements
671  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
672  *		or -FDT_ERR_BADLAYOUT if not enough data
673  */
674 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
675 		u32 *array, int count);
676 
677 /**
678  * Look up a property in a node and return its contents in an integer
679  * array of given length. The property must exist but may have less data that
680  * expected (4*count bytes). It may have more, but this will be ignored.
681  *
682  * @param blob		FDT blob
683  * @param node		node to examine
684  * @param prop_name	name of property to find
685  * @param array		array to fill with data
686  * @param count		number of array elements
687  * @return number of array elements if ok, or -FDT_ERR_NOTFOUND if the
688  *		property is not found
689  */
690 int fdtdec_get_int_array_count(const void *blob, int node,
691 			       const char *prop_name, u32 *array, int count);
692 
693 /**
694  * Look up a property in a node and return a pointer to its contents as a
695  * unsigned int array of given length. The property must have at least enough
696  * data for the array ('count' cells). It may have more, but this will be
697  * ignored. The data is not copied.
698  *
699  * Note that you must access elements of the array with fdt32_to_cpu(),
700  * since the elements will be big endian even on a little endian machine.
701  *
702  * @param blob		FDT blob
703  * @param node		node to examine
704  * @param prop_name	name of property to find
705  * @param count		number of array elements
706  * @return pointer to array if found, or NULL if the property is not
707  *		found or there is not enough data
708  */
709 const u32 *fdtdec_locate_array(const void *blob, int node,
710 			       const char *prop_name, int count);
711 
712 /**
713  * Look up a boolean property in a node and return it.
714  *
715  * A boolean properly is true if present in the device tree and false if not
716  * present, regardless of its value.
717  *
718  * @param blob	FDT blob
719  * @param node	node to examine
720  * @param prop_name	name of property to find
721  * @return 1 if the properly is present; 0 if it isn't present
722  */
723 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
724 
725 /*
726  * Count child nodes of one parent node.
727  *
728  * @param blob	FDT blob
729  * @param node	parent node
730  * @return number of child node; 0 if there is not child node
731  */
732 int fdtdec_get_child_count(const void *blob, int node);
733 
734 /**
735  * Look in the FDT for a config item with the given name and return its value
736  * as a 32-bit integer. The property must have at least 4 bytes of data. The
737  * value of the first cell is returned.
738  *
739  * @param blob		FDT blob to use
740  * @param prop_name	Node property name
741  * @param default_val	default value to return if the property is not found
742  * @return integer value, if found, or default_val if not
743  */
744 int fdtdec_get_config_int(const void *blob, const char *prop_name,
745 		int default_val);
746 
747 /**
748  * Look in the FDT for a config item with the given name
749  * and return whether it exists.
750  *
751  * @param blob		FDT blob
752  * @param prop_name	property name to look up
753  * @return 1, if it exists, or 0 if not
754  */
755 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
756 
757 /**
758  * Look in the FDT for a config item with the given name and return its value
759  * as a string.
760  *
761  * @param blob          FDT blob
762  * @param prop_name     property name to look up
763  * @returns property string, NULL on error.
764  */
765 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
766 
767 /*
768  * Look up a property in a node and return its contents in a byte
769  * array of given length. The property must have at least enough data for
770  * the array (count bytes). It may have more, but this will be ignored.
771  *
772  * @param blob		FDT blob
773  * @param node		node to examine
774  * @param prop_name	name of property to find
775  * @param array		array to fill with data
776  * @param count		number of array elements
777  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
778  *		or -FDT_ERR_BADLAYOUT if not enough data
779  */
780 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
781 		u8 *array, int count);
782 
783 /**
784  * Look up a property in a node and return a pointer to its contents as a
785  * byte array of given length. The property must have at least enough data
786  * for the array (count bytes). It may have more, but this will be ignored.
787  * The data is not copied.
788  *
789  * @param blob		FDT blob
790  * @param node		node to examine
791  * @param prop_name	name of property to find
792  * @param count		number of array elements
793  * @return pointer to byte array if found, or NULL if the property is not
794  *		found or there is not enough data
795  */
796 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
797 			     const char *prop_name, int count);
798 
799 /**
800  * Look up a property in a node which contains a memory region address and
801  * size. Then return a pointer to this address.
802  *
803  * The property must hold one address with a length. This is only tested on
804  * 32-bit machines.
805  *
806  * @param blob		FDT blob
807  * @param node		node to examine
808  * @param prop_name	name of property to find
809  * @param basep		Returns base address of region
810  * @param size		Returns size of region
811  * @return 0 if ok, -1 on error (property not found)
812  */
813 int fdtdec_decode_region(const void *blob, int node, const char *prop_name,
814 			 fdt_addr_t *basep, fdt_size_t *sizep);
815 
816 /**
817  * Obtain an indexed resource from a device property.
818  *
819  * @param fdt		FDT blob
820  * @param node		node to examine
821  * @param property	name of the property to parse
822  * @param index		index of the resource to retrieve
823  * @param res		returns the resource
824  * @return 0 if ok, negative on error
825  */
826 int fdt_get_resource(const void *fdt, int node, const char *property,
827 		     unsigned int index, struct fdt_resource *res);
828 
829 /**
830  * Obtain a named resource from a device property.
831  *
832  * Look up the index of the name in a list of strings and return the resource
833  * at that index.
834  *
835  * @param fdt		FDT blob
836  * @param node		node to examine
837  * @param property	name of the property to parse
838  * @param prop_names	name of the property containing the list of names
839  * @param name		the name of the entry to look up
840  * @param res		returns the resource
841  */
842 int fdt_get_named_resource(const void *fdt, int node, const char *property,
843 			   const char *prop_names, const char *name,
844 			   struct fdt_resource *res);
845 
846 /**
847  * Decode a named region within a memory bank of a given type.
848  *
849  * This function handles selection of a memory region. The region is
850  * specified as an offset/size within a particular type of memory.
851  *
852  * The properties used are:
853  *
854  *	<mem_type>-memory<suffix> for the name of the memory bank
855  *	<mem_type>-offset<suffix> for the offset in that bank
856  *
857  * The property value must have an offset and a size. The function checks
858  * that the region is entirely within the memory bank.5
859  *
860  * @param blob		FDT blob
861  * @param node		Node containing the properties (-1 for /config)
862  * @param mem_type	Type of memory to use, which is a name, such as
863  *			"u-boot" or "kernel".
864  * @param suffix	String to append to the memory/offset
865  *			property names
866  * @param basep		Returns base of region
867  * @param sizep		Returns size of region
868  * @return 0 if OK, -ive on error
869  */
870 int fdtdec_decode_memory_region(const void *blob, int node,
871 				const char *mem_type, const char *suffix,
872 				fdt_addr_t *basep, fdt_size_t *sizep);
873 
874 /* Display timings from linux include/video/display_timing.h */
875 enum display_flags {
876 	DISPLAY_FLAGS_HSYNC_LOW		= 1 << 0,
877 	DISPLAY_FLAGS_HSYNC_HIGH	= 1 << 1,
878 	DISPLAY_FLAGS_VSYNC_LOW		= 1 << 2,
879 	DISPLAY_FLAGS_VSYNC_HIGH	= 1 << 3,
880 
881 	/* data enable flag */
882 	DISPLAY_FLAGS_DE_LOW		= 1 << 4,
883 	DISPLAY_FLAGS_DE_HIGH		= 1 << 5,
884 	/* drive data on pos. edge */
885 	DISPLAY_FLAGS_PIXDATA_POSEDGE	= 1 << 6,
886 	/* drive data on neg. edge */
887 	DISPLAY_FLAGS_PIXDATA_NEGEDGE	= 1 << 7,
888 	DISPLAY_FLAGS_INTERLACED	= 1 << 8,
889 	DISPLAY_FLAGS_DOUBLESCAN	= 1 << 9,
890 	DISPLAY_FLAGS_DOUBLECLK		= 1 << 10,
891 };
892 
893 /*
894  * A single signal can be specified via a range of minimal and maximal values
895  * with a typical value, that lies somewhere inbetween.
896  */
897 struct timing_entry {
898 	u32 min;
899 	u32 typ;
900 	u32 max;
901 };
902 
903 /*
904  * Single "mode" entry. This describes one set of signal timings a display can
905  * have in one setting. This struct can later be converted to struct videomode
906  * (see include/video/videomode.h). As each timing_entry can be defined as a
907  * range, one struct display_timing may become multiple struct videomodes.
908  *
909  * Example: hsync active high, vsync active low
910  *
911  *				    Active Video
912  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
913  *	  |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
914  *	  |	     |	 porch  |		     |	 porch	 |
915  *
916  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
917  *
918  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
919  */
920 struct display_timing {
921 	struct timing_entry pixelclock;
922 
923 	struct timing_entry hactive;		/* hor. active video */
924 	struct timing_entry hfront_porch;	/* hor. front porch */
925 	struct timing_entry hback_porch;	/* hor. back porch */
926 	struct timing_entry hsync_len;		/* hor. sync len */
927 
928 	struct timing_entry vactive;		/* ver. active video */
929 	struct timing_entry vfront_porch;	/* ver. front porch */
930 	struct timing_entry vback_porch;	/* ver. back porch */
931 	struct timing_entry vsync_len;		/* ver. sync len */
932 
933 	enum display_flags flags;		/* display flags */
934 	bool hdmi_monitor;			/* is hdmi monitor? */
935 };
936 
937 /**
938  * fdtdec_decode_display_timing() - decode display timings
939  *
940  * Decode display timings from the supplied 'display-timings' node.
941  * See doc/device-tree-bindings/video/display-timing.txt for binding
942  * information.
943  *
944  * @param blob		FDT blob
945  * @param node		'display-timing' node containing the timing subnodes
946  * @param index		Index number to read (0=first timing subnode)
947  * @param config	Place to put timings
948  * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
949  */
950 int fdtdec_decode_display_timing(const void *blob, int node, int index,
951 				 struct display_timing *config);
952 
953 /**
954  * fdtdec_setup_memory_size() - decode and setup gd->ram_size
955  *
956  * Decode the /memory 'reg' property to determine the size of the first memory
957  * bank, populate the global data with the size of the first bank of memory.
958  *
959  * This function should be called from a boards dram_init(). This helper
960  * function allows for boards to query the device tree for DRAM size instead of
961  * hard coding the value in the case where the memory size cannot be detected
962  * automatically.
963  *
964  * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
965  * invalid
966  */
967 int fdtdec_setup_memory_size(void);
968 
969 /**
970  * fdtdec_setup_memory_banksize() - decode and populate gd->bd->bi_dram
971  *
972  * Decode the /memory 'reg' property to determine the address and size of the
973  * memory banks. Use this data to populate the global data board info with the
974  * phys address and size of memory banks.
975  *
976  * This function should be called from a boards dram_init_banksize(). This
977  * helper function allows for boards to query the device tree for memory bank
978  * information instead of hard coding the information in cases where it cannot
979  * be detected automatically.
980  *
981  * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
982  * invalid
983  */
984 int fdtdec_setup_memory_banksize(void);
985 
986 /**
987  * Set up the device tree ready for use
988  */
989 int fdtdec_setup(void);
990 
991 /**
992  * Board-specific FDT initialization. Returns the address to a device tree blob.
993  * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
994  * and the board implements it.
995  */
996 void *board_fdt_blob_setup(void);
997 
998 #endif
999