xref: /openbmc/u-boot/include/fdtdec.h (revision 192bc694)
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 #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 (-1ULL)
28 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
29 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
30 #else
31 #define FDT_ADDR_T_NONE (-1U)
32 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
33 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
34 #endif
35 
36 /* Information obtained about memory from the FDT */
37 struct fdt_memory {
38 	fdt_addr_t start;
39 	fdt_addr_t end;
40 };
41 
42 #ifdef CONFIG_SPL_BUILD
43 #define SPL_BUILD	1
44 #else
45 #define SPL_BUILD	0
46 #endif
47 
48 /*
49  * Information about a resource. start is the first address of the resource
50  * and end is the last address (inclusive). The length of the resource will
51  * be equal to: end - start + 1.
52  */
53 struct fdt_resource {
54 	fdt_addr_t start;
55 	fdt_addr_t end;
56 };
57 
58 enum fdt_pci_space {
59 	FDT_PCI_SPACE_CONFIG = 0,
60 	FDT_PCI_SPACE_IO = 0x01000000,
61 	FDT_PCI_SPACE_MEM32 = 0x02000000,
62 	FDT_PCI_SPACE_MEM64 = 0x03000000,
63 	FDT_PCI_SPACE_MEM32_PREF = 0x42000000,
64 	FDT_PCI_SPACE_MEM64_PREF = 0x43000000,
65 };
66 
67 #define FDT_PCI_ADDR_CELLS	3
68 #define FDT_PCI_SIZE_CELLS	2
69 #define FDT_PCI_REG_SIZE	\
70 	((FDT_PCI_ADDR_CELLS + FDT_PCI_SIZE_CELLS) * sizeof(u32))
71 
72 /*
73  * The Open Firmware spec defines PCI physical address as follows:
74  *
75  *          bits# 31 .... 24 23 .... 16 15 .... 08 07 .... 00
76  *
77  * phys.hi  cell:  npt000ss   bbbbbbbb   dddddfff   rrrrrrrr
78  * phys.mid cell:  hhhhhhhh   hhhhhhhh   hhhhhhhh   hhhhhhhh
79  * phys.lo  cell:  llllllll   llllllll   llllllll   llllllll
80  *
81  * where:
82  *
83  * n:        is 0 if the address is relocatable, 1 otherwise
84  * p:        is 1 if addressable region is prefetchable, 0 otherwise
85  * t:        is 1 if the address is aliased (for non-relocatable I/O) below 1MB
86  *           (for Memory), or below 64KB (for relocatable I/O)
87  * ss:       is the space code, denoting the address space
88  * bbbbbbbb: is the 8-bit Bus Number
89  * ddddd:    is the 5-bit Device Number
90  * fff:      is the 3-bit Function Number
91  * rrrrrrrr: is the 8-bit Register Number
92  * hhhhhhhh: is a 32-bit unsigned number
93  * llllllll: is a 32-bit unsigned number
94  */
95 struct fdt_pci_addr {
96 	u32	phys_hi;
97 	u32	phys_mid;
98 	u32	phys_lo;
99 };
100 
101 /**
102  * Compute the size of a resource.
103  *
104  * @param res	the resource to operate on
105  * @return the size of the resource
106  */
107 static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
108 {
109 	return res->end - res->start + 1;
110 }
111 
112 /**
113  * Compat types that we know about and for which we might have drivers.
114  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
115  * within drivers.
116  */
117 enum fdt_compat_id {
118 	COMPAT_UNKNOWN,
119 	COMPAT_NVIDIA_TEGRA20_EMC,	/* Tegra20 memory controller */
120 	COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
121 	COMPAT_NVIDIA_TEGRA20_NAND,	/* Tegra2 NAND controller */
122 	COMPAT_NVIDIA_TEGRA20_PWM,	/* Tegra 2 PWM controller */
123 	COMPAT_NVIDIA_TEGRA124_DC,	/* Tegra 124 Display controller */
124 	COMPAT_NVIDIA_TEGRA124_SOR,	/* Tegra 124 Serial Output Resource */
125 	COMPAT_NVIDIA_TEGRA124_PMC,	/* Tegra 124 power mgmt controller */
126 	COMPAT_NVIDIA_TEGRA20_DC,	/* Tegra 2 Display controller */
127 	COMPAT_NVIDIA_TEGRA210_SDMMC,	/* Tegra210 SDMMC controller */
128 	COMPAT_NVIDIA_TEGRA124_SDMMC,	/* Tegra124 SDMMC controller */
129 	COMPAT_NVIDIA_TEGRA30_SDMMC,	/* Tegra30 SDMMC controller */
130 	COMPAT_NVIDIA_TEGRA20_SDMMC,	/* Tegra20 SDMMC controller */
131 	COMPAT_NVIDIA_TEGRA124_XUSB_PADCTL,
132 					/* Tegra124 XUSB pad controller */
133 	COMPAT_NVIDIA_TEGRA210_XUSB_PADCTL,
134 					/* Tegra210 XUSB pad controller */
135 	COMPAT_SMSC_LAN9215,		/* SMSC 10/100 Ethernet LAN9215 */
136 	COMPAT_SAMSUNG_EXYNOS5_SROMC,	/* Exynos5 SROMC */
137 	COMPAT_SAMSUNG_S3C2440_I2C,	/* Exynos I2C Controller */
138 	COMPAT_SAMSUNG_EXYNOS5_SOUND,	/* Exynos Sound */
139 	COMPAT_WOLFSON_WM8994_CODEC,	/* Wolfson WM8994 Sound Codec */
140 	COMPAT_GOOGLE_CROS_EC_KEYB,	/* Google CROS_EC Keyboard */
141 	COMPAT_SAMSUNG_EXYNOS_USB_PHY,	/* Exynos phy controller for usb2.0 */
142 	COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
143 	COMPAT_SAMSUNG_EXYNOS_TMU,	/* Exynos TMU */
144 	COMPAT_SAMSUNG_EXYNOS_FIMD,	/* Exynos Display controller */
145 	COMPAT_SAMSUNG_EXYNOS_MIPI_DSI,	/* Exynos mipi dsi */
146 	COMPAT_SAMSUNG_EXYNOS5_DP,	/* Exynos Display port controller */
147 	COMPAT_SAMSUNG_EXYNOS_DWMMC,	/* Exynos DWMMC controller */
148 	COMPAT_SAMSUNG_EXYNOS_MMC,	/* Exynos MMC controller */
149 	COMPAT_SAMSUNG_EXYNOS_SERIAL,	/* Exynos UART */
150 	COMPAT_MAXIM_MAX77686_PMIC,	/* MAX77686 PMIC */
151 	COMPAT_GENERIC_SPI_FLASH,	/* Generic SPI Flash chip */
152 	COMPAT_MAXIM_98095_CODEC,	/* MAX98095 Codec */
153 	COMPAT_SAMSUNG_EXYNOS5_I2C,	/* Exynos5 High Speed I2C Controller */
154 	COMPAT_SANDBOX_LCD_SDL,		/* Sandbox LCD emulation with SDL */
155 	COMPAT_SAMSUNG_EXYNOS_SYSMMU,	/* Exynos sysmmu */
156 	COMPAT_INTEL_MICROCODE,		/* Intel microcode update */
157 	COMPAT_MEMORY_SPD,		/* Memory SPD information */
158 	COMPAT_INTEL_PANTHERPOINT_AHCI,	/* Intel Pantherpoint AHCI */
159 	COMPAT_INTEL_MODEL_206AX,	/* Intel Model 206AX CPU */
160 	COMPAT_INTEL_GMA,		/* Intel Graphics Media Accelerator */
161 	COMPAT_AMS_AS3722,		/* AMS AS3722 PMIC */
162 	COMPAT_INTEL_ICH_SPI,		/* Intel ICH7/9 SPI controller */
163 	COMPAT_INTEL_QRK_MRC,		/* Intel Quark MRC */
164 	COMPAT_INTEL_X86_PINCTRL,	/* Intel ICH7/9 pin control */
165 	COMPAT_SOCIONEXT_XHCI,		/* Socionext UniPhier xHCI */
166 	COMPAT_INTEL_PCH,		/* Intel PCH */
167 	COMPAT_INTEL_IRQ_ROUTER,	/* Intel Interrupt Router */
168 	COMPAT_ALTERA_SOCFPGA_DWMAC,	/* SoCFPGA Ethernet controller */
169 	COMPAT_ALTERA_SOCFPGA_DWMMC,	/* SoCFPGA DWMMC controller */
170 	COMPAT_ALTERA_SOCFPGA_DWC2USB,	/* SoCFPGA DWC2 USB controller */
171 	COMPAT_INTEL_BAYTRAIL_FSP,	/* Intel Bay Trail FSP */
172 	COMPAT_INTEL_BAYTRAIL_FSP_MDP,	/* Intel FSP memory-down params */
173 	COMPAT_INTEL_IVYBRIDGE_FSP,	/* Intel Ivy Bridge FSP */
174 
175 	COMPAT_COUNT,
176 };
177 
178 #define MAX_PHANDLE_ARGS 16
179 struct fdtdec_phandle_args {
180 	int node;
181 	int args_count;
182 	uint32_t args[MAX_PHANDLE_ARGS];
183 };
184 
185 /**
186  * fdtdec_parse_phandle_with_args() - Find a node pointed by phandle in a list
187  *
188  * This function is useful to parse lists of phandles and their arguments.
189  *
190  * Example:
191  *
192  * phandle1: node1 {
193  *	#list-cells = <2>;
194  * }
195  *
196  * phandle2: node2 {
197  *	#list-cells = <1>;
198  * }
199  *
200  * node3 {
201  *	list = <&phandle1 1 2 &phandle2 3>;
202  * }
203  *
204  * To get a device_node of the `node2' node you may call this:
205  * fdtdec_parse_phandle_with_args(blob, node3, "list", "#list-cells", 0, 1,
206  *				  &args);
207  *
208  * (This function is a modified version of __of_parse_phandle_with_args() from
209  * Linux 3.18)
210  *
211  * @blob:	Pointer to device tree
212  * @src_node:	Offset of device tree node containing a list
213  * @list_name:	property name that contains a list
214  * @cells_name:	property name that specifies the phandles' arguments count,
215  *		or NULL to use @cells_count
216  * @cells_count: Cell count to use if @cells_name is NULL
217  * @index:	index of a phandle to parse out
218  * @out_args:	optional pointer to output arguments structure (will be filled)
219  * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
220  *	@list_name does not exist, a phandle was not found, @cells_name
221  *	could not be found, the arguments were truncated or there were too
222  *	many arguments.
223  *
224  */
225 int fdtdec_parse_phandle_with_args(const void *blob, int src_node,
226 				   const char *list_name,
227 				   const char *cells_name,
228 				   int cell_count, int index,
229 				   struct fdtdec_phandle_args *out_args);
230 
231 /**
232  * Find the next numbered alias for a peripheral. This is used to enumerate
233  * all the peripherals of a certain type.
234  *
235  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
236  * this function will return a pointer to the node the alias points to, and
237  * then update *upto to 1. Next time you call this function, the next node
238  * will be returned.
239  *
240  * All nodes returned will match the compatible ID, as it is assumed that
241  * all peripherals use the same driver.
242  *
243  * @param blob		FDT blob to use
244  * @param name		Root name of alias to search for
245  * @param id		Compatible ID to look for
246  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
247  */
248 int fdtdec_next_alias(const void *blob, const char *name,
249 		enum fdt_compat_id id, int *upto);
250 
251 /**
252  * Find the compatible ID for a given node.
253  *
254  * Generally each node has at least one compatible string attached to it.
255  * This function looks through our list of known compatible strings and
256  * returns the corresponding ID which matches the compatible string.
257  *
258  * @param blob		FDT blob to use
259  * @param node		Node containing compatible string to find
260  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
261  */
262 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
263 
264 /**
265  * Find the next compatible node for a peripheral.
266  *
267  * Do the first call with node = 0. This function will return a pointer to
268  * the next compatible node. Next time you call this function, pass the
269  * value returned, and the next node will be provided.
270  *
271  * @param blob		FDT blob to use
272  * @param node		Start node for search
273  * @param id		Compatible ID to look for (enum fdt_compat_id)
274  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
275  */
276 int fdtdec_next_compatible(const void *blob, int node,
277 		enum fdt_compat_id id);
278 
279 /**
280  * Find the next compatible subnode for a peripheral.
281  *
282  * Do the first call with node set to the parent and depth = 0. This
283  * function will return the offset of the next compatible node. Next time
284  * you call this function, pass the node value returned last time, with
285  * depth unchanged, and the next node will be provided.
286  *
287  * @param blob		FDT blob to use
288  * @param node		Start node for search
289  * @param id		Compatible ID to look for (enum fdt_compat_id)
290  * @param depthp	Current depth (set to 0 before first call)
291  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
292  */
293 int fdtdec_next_compatible_subnode(const void *blob, int node,
294 		enum fdt_compat_id id, int *depthp);
295 
296 /*
297  * Look up an address property in a node and return the parsed address, and
298  * optionally the parsed size.
299  *
300  * This variant assumes a known and fixed number of cells are used to
301  * represent the address and size.
302  *
303  * You probably don't want to use this function directly except to parse
304  * non-standard properties, and never to parse the "reg" property. Instead,
305  * use one of the "auto" variants below, which automatically honor the
306  * #address-cells and #size-cells properties in the parent node.
307  *
308  * @param blob	FDT blob
309  * @param node	node to examine
310  * @param prop_name	name of property to find
311  * @param index	which address to retrieve from a list of addresses. Often 0.
312  * @param na	the number of cells used to represent an address
313  * @param ns	the number of cells used to represent a size
314  * @param sizep	a pointer to store the size into. Use NULL if not required
315  * @return address, if found, or FDT_ADDR_T_NONE if not
316  */
317 fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
318 		const char *prop_name, int index, int na, int ns,
319 		fdt_size_t *sizep);
320 
321 /*
322  * Look up an address property in a node and return the parsed address, and
323  * optionally the parsed size.
324  *
325  * This variant automatically determines the number of cells used to represent
326  * the address and size by parsing the provided parent node's #address-cells
327  * and #size-cells properties.
328  *
329  * @param blob	FDT blob
330  * @param parent	parent node of @node
331  * @param node	node to examine
332  * @param prop_name	name of property to find
333  * @param index	which address to retrieve from a list of addresses. Often 0.
334  * @param sizep	a pointer to store the size into. Use NULL if not required
335  * @return address, if found, or FDT_ADDR_T_NONE if not
336  */
337 fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
338 		int node, const char *prop_name, int index, fdt_size_t *sizep);
339 
340 /*
341  * Look up an address property in a node and return the parsed address, and
342  * optionally the parsed size.
343  *
344  * This variant automatically determines the number of cells used to represent
345  * the address and size by parsing the parent node's #address-cells
346  * and #size-cells properties. The parent node is automatically found.
347  *
348  * The automatic parent lookup implemented by this function is slow.
349  * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
350  * possible.
351  *
352  * @param blob	FDT blob
353  * @param parent	parent node of @node
354  * @param node	node to examine
355  * @param prop_name	name of property to find
356  * @param index	which address to retrieve from a list of addresses. Often 0.
357  * @param sizep	a pointer to store the size into. Use NULL if not required
358  * @return address, if found, or FDT_ADDR_T_NONE if not
359  */
360 fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
361 		const char *prop_name, int index, fdt_size_t *sizep);
362 
363 /*
364  * Look up an address property in a node and return the parsed address.
365  *
366  * This variant hard-codes the number of cells used to represent the address
367  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
368  * always returns the first address value in the property (index 0).
369  *
370  * Use of this function is not recommended due to the hard-coding of cell
371  * counts. There is no programmatic validation that these hard-coded values
372  * actually match the device tree content in any way at all. This assumption
373  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
374  * set in the U-Boot build and exercising strict control over DT content to
375  * ensure use of matching #address-cells/#size-cells properties. However, this
376  * approach is error-prone; those familiar with DT will not expect the
377  * assumption to exist, and could easily invalidate it. If the assumption is
378  * invalidated, this function will not report the issue, and debugging will
379  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
380  *
381  * @param blob	FDT blob
382  * @param node	node to examine
383  * @param prop_name	name of property to find
384  * @return address, if found, or FDT_ADDR_T_NONE if not
385  */
386 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
387 		const char *prop_name);
388 
389 /*
390  * Look up an address property in a node and return the parsed address, and
391  * optionally the parsed size.
392  *
393  * This variant hard-codes the number of cells used to represent the address
394  * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
395  * always returns the first address value in the property (index 0).
396  *
397  * Use of this function is not recommended due to the hard-coding of cell
398  * counts. There is no programmatic validation that these hard-coded values
399  * actually match the device tree content in any way at all. This assumption
400  * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
401  * set in the U-Boot build and exercising strict control over DT content to
402  * ensure use of matching #address-cells/#size-cells properties. However, this
403  * approach is error-prone; those familiar with DT will not expect the
404  * assumption to exist, and could easily invalidate it. If the assumption is
405  * invalidated, this function will not report the issue, and debugging will
406  * be required. Instead, use fdtdec_get_addr_size_auto_parent().
407  *
408  * @param blob	FDT blob
409  * @param node	node to examine
410  * @param prop_name	name of property to find
411  * @param sizep	a pointer to store the size into. Use NULL if not required
412  * @return address, if found, or FDT_ADDR_T_NONE if not
413  */
414 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
415 		const char *prop_name, fdt_size_t *sizep);
416 
417 /**
418  * Look at an address property in a node and return the pci address which
419  * corresponds to the given type in the form of fdt_pci_addr.
420  * The property must hold one fdt_pci_addr with a lengh.
421  *
422  * @param blob		FDT blob
423  * @param node		node to examine
424  * @param type		pci address type (FDT_PCI_SPACE_xxx)
425  * @param prop_name	name of property to find
426  * @param addr		returns pci address in the form of fdt_pci_addr
427  * @return 0 if ok, -ENOENT if the property did not exist, -EINVAL if the
428  *		format of the property was invalid, -ENXIO if the requested
429  *		address type was not found
430  */
431 int fdtdec_get_pci_addr(const void *blob, int node, enum fdt_pci_space type,
432 		const char *prop_name, struct fdt_pci_addr *addr);
433 
434 /**
435  * Look at the compatible property of a device node that represents a PCI
436  * device and extract pci vendor id and device id from it.
437  *
438  * @param blob		FDT blob
439  * @param node		node to examine
440  * @param vendor	vendor id of the pci device
441  * @param device	device id of the pci device
442  * @return 0 if ok, negative on error
443  */
444 int fdtdec_get_pci_vendev(const void *blob, int node,
445 		u16 *vendor, u16 *device);
446 
447 /**
448  * Look at the pci address of a device node that represents a PCI device
449  * and return base address of the pci device's registers.
450  *
451  * @param dev		device to examine
452  * @param addr		pci address in the form of fdt_pci_addr
453  * @param bar		returns base address of the pci device's registers
454  * @return 0 if ok, negative on error
455  */
456 int fdtdec_get_pci_bar32(struct udevice *dev, struct fdt_pci_addr *addr,
457 			 u32 *bar);
458 
459 /**
460  * Look up a 32-bit integer property in a node and return it. The property
461  * must have at least 4 bytes of data. The value of the first cell is
462  * returned.
463  *
464  * @param blob	FDT blob
465  * @param node	node to examine
466  * @param prop_name	name of property to find
467  * @param default_val	default value to return if the property is not found
468  * @return integer value, if found, or default_val if not
469  */
470 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
471 		s32 default_val);
472 
473 /**
474  * Unsigned version of fdtdec_get_int. The property must have at least
475  * 4 bytes of data. The value of the first cell is returned.
476  *
477  * @param blob	FDT blob
478  * @param node	node to examine
479  * @param prop_name	name of property to find
480  * @param default_val	default value to return if the property is not found
481  * @return unsigned integer value, if found, or default_val if not
482  */
483 unsigned int fdtdec_get_uint(const void *blob, int node, const char *prop_name,
484 			unsigned int default_val);
485 
486 /**
487  * Get a variable-sized number from a property
488  *
489  * This reads a number from one or more cells.
490  *
491  * @param ptr	Pointer to property
492  * @param cells	Number of cells containing the number
493  * @return the value in the cells
494  */
495 u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells);
496 
497 /**
498  * Look up a 64-bit integer property in a node and return it. The property
499  * must have at least 8 bytes of data (2 cells). The first two cells are
500  * concatenated to form a 8 bytes value, where the first cell is top half and
501  * the second cell is bottom half.
502  *
503  * @param blob	FDT blob
504  * @param node	node to examine
505  * @param prop_name	name of property to find
506  * @param default_val	default value to return if the property is not found
507  * @return integer value, if found, or default_val if not
508  */
509 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
510 		uint64_t default_val);
511 
512 /**
513  * Checks whether a node is enabled.
514  * This looks for a 'status' property. If this exists, then returns 1 if
515  * the status is 'ok' and 0 otherwise. If there is no status property,
516  * it returns 1 on the assumption that anything mentioned should be enabled
517  * by default.
518  *
519  * @param blob	FDT blob
520  * @param node	node to examine
521  * @return integer value 0 (not enabled) or 1 (enabled)
522  */
523 int fdtdec_get_is_enabled(const void *blob, int node);
524 
525 /**
526  * Make sure we have a valid fdt available to control U-Boot.
527  *
528  * If not, a message is printed to the console if the console is ready.
529  *
530  * @return 0 if all ok, -1 if not
531  */
532 int fdtdec_prepare_fdt(void);
533 
534 /**
535  * Checks that we have a valid fdt available to control U-Boot.
536 
537  * However, if not then for the moment nothing is done, since this function
538  * is called too early to panic().
539  *
540  * @returns 0
541  */
542 int fdtdec_check_fdt(void);
543 
544 /**
545  * Find the nodes for a peripheral and return a list of them in the correct
546  * order. This is used to enumerate all the peripherals of a certain type.
547  *
548  * To use this, optionally set up a /aliases node with alias properties for
549  * a peripheral. For example, for usb you could have:
550  *
551  * aliases {
552  *		usb0 = "/ehci@c5008000";
553  *		usb1 = "/ehci@c5000000";
554  * };
555  *
556  * Pass "usb" as the name to this function and will return a list of two
557  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
558  *
559  * All nodes returned will match the compatible ID, as it is assumed that
560  * all peripherals use the same driver.
561  *
562  * If no alias node is found, then the node list will be returned in the
563  * order found in the fdt. If the aliases mention a node which doesn't
564  * exist, then this will be ignored. If nodes are found with no aliases,
565  * they will be added in any order.
566  *
567  * If there is a gap in the aliases, then this function return a 0 node at
568  * that position. The return value will also count these gaps.
569  *
570  * This function checks node properties and will not return nodes which are
571  * marked disabled (status = "disabled").
572  *
573  * @param blob		FDT blob to use
574  * @param name		Root name of alias to search for
575  * @param id		Compatible ID to look for
576  * @param node_list	Place to put list of found nodes
577  * @param maxcount	Maximum number of nodes to find
578  * @return number of nodes found on success, FTD_ERR_... on error
579  */
580 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
581 			enum fdt_compat_id id, int *node_list, int maxcount);
582 
583 /*
584  * This function is similar to fdtdec_find_aliases_for_id() except that it
585  * adds to the node_list that is passed in. Any 0 elements are considered
586  * available for allocation - others are considered already used and are
587  * skipped.
588  *
589  * You can use this by calling fdtdec_find_aliases_for_id() with an
590  * uninitialised array, then setting the elements that are returned to -1,
591  * say, then calling this function, perhaps with a different compat id.
592  * Any elements you get back that are >0 are new nodes added by the call
593  * to this function.
594  *
595  * Note that if you have some nodes with aliases and some without, you are
596  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
597  * one compat_id may fill in positions for which you have aliases defined
598  * for another compat_id. When you later call *this* function with the second
599  * compat_id, the alias positions may already be used. A debug warning may
600  * be generated in this case, but it is safest to define aliases for all
601  * nodes when you care about the ordering.
602  */
603 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
604 			enum fdt_compat_id id, int *node_list, int maxcount);
605 
606 /**
607  * Get the alias sequence number of a node
608  *
609  * This works out whether a node is pointed to by an alias, and if so, the
610  * sequence number of that alias. Aliases are of the form <base><num> where
611  * <num> is the sequence number. For example spi2 would be sequence number
612  * 2.
613  *
614  * @param blob		Device tree blob (if NULL, then error is returned)
615  * @param base		Base name for alias (before the underscore)
616  * @param node		Node to look up
617  * @param seqp		This is set to the sequence number if one is found,
618  *			but otherwise the value is left alone
619  * @return 0 if a sequence was found, -ve if not
620  */
621 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
622 			 int *seqp);
623 
624 /**
625  * Get a property from the /chosen node
626  *
627  * @param blob		Device tree blob (if NULL, then NULL is returned)
628  * @param name		Property name to look up
629  * @return Value of property, or NULL if it does not exist
630  */
631 const char *fdtdec_get_chosen_prop(const void *blob, const char *name);
632 
633 /**
634  * Get the offset of the given /chosen node
635  *
636  * This looks up a property in /chosen containing the path to another node,
637  * then finds the offset of that node.
638  *
639  * @param blob		Device tree blob (if NULL, then error is returned)
640  * @param name		Property name, e.g. "stdout-path"
641  * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
642  */
643 int fdtdec_get_chosen_node(const void *blob, const char *name);
644 
645 /*
646  * Get the name for a compatible ID
647  *
648  * @param id		Compatible ID to look for
649  * @return compatible string for that id
650  */
651 const char *fdtdec_get_compatible(enum fdt_compat_id id);
652 
653 /* Look up a phandle and follow it to its node. Then return the offset
654  * of that node.
655  *
656  * @param blob		FDT blob
657  * @param node		node to examine
658  * @param prop_name	name of property to find
659  * @return node offset if found, -ve error code on error
660  */
661 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
662 
663 /**
664  * Look up a property in a node and return its contents in an integer
665  * array of given length. The property must have at least enough data for
666  * the array (4*count bytes). It may have more, but this will be ignored.
667  *
668  * @param blob		FDT blob
669  * @param node		node to examine
670  * @param prop_name	name of property to find
671  * @param array		array to fill with data
672  * @param count		number of array elements
673  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
674  *		or -FDT_ERR_BADLAYOUT if not enough data
675  */
676 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
677 		u32 *array, int count);
678 
679 /**
680  * Look up a property in a node and return its contents in an integer
681  * array of given length. The property must exist but may have less data that
682  * expected (4*count bytes). It may have more, but this will be ignored.
683  *
684  * @param blob		FDT blob
685  * @param node		node to examine
686  * @param prop_name	name of property to find
687  * @param array		array to fill with data
688  * @param count		number of array elements
689  * @return number of array elements if ok, or -FDT_ERR_NOTFOUND if the
690  *		property is not found
691  */
692 int fdtdec_get_int_array_count(const void *blob, int node,
693 			       const char *prop_name, u32 *array, int count);
694 
695 /**
696  * Look up a property in a node and return a pointer to its contents as a
697  * unsigned int array of given length. The property must have at least enough
698  * data for the array ('count' cells). It may have more, but this will be
699  * ignored. The data is not copied.
700  *
701  * Note that you must access elements of the array with fdt32_to_cpu(),
702  * since the elements will be big endian even on a little endian machine.
703  *
704  * @param blob		FDT blob
705  * @param node		node to examine
706  * @param prop_name	name of property to find
707  * @param count		number of array elements
708  * @return pointer to array if found, or NULL if the property is not
709  *		found or there is not enough data
710  */
711 const u32 *fdtdec_locate_array(const void *blob, int node,
712 			       const char *prop_name, int count);
713 
714 /**
715  * Look up a boolean property in a node and return it.
716  *
717  * A boolean properly is true if present in the device tree and false if not
718  * present, regardless of its value.
719  *
720  * @param blob	FDT blob
721  * @param node	node to examine
722  * @param prop_name	name of property to find
723  * @return 1 if the properly is present; 0 if it isn't present
724  */
725 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
726 
727 /**
728  * Look in the FDT for a config item with the given name and return its value
729  * as a 32-bit integer. The property must have at least 4 bytes of data. The
730  * value of the first cell is returned.
731  *
732  * @param blob		FDT blob to use
733  * @param prop_name	Node property name
734  * @param default_val	default value to return if the property is not found
735  * @return integer value, if found, or default_val if not
736  */
737 int fdtdec_get_config_int(const void *blob, const char *prop_name,
738 		int default_val);
739 
740 /**
741  * Look in the FDT for a config item with the given name
742  * and return whether it exists.
743  *
744  * @param blob		FDT blob
745  * @param prop_name	property name to look up
746  * @return 1, if it exists, or 0 if not
747  */
748 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
749 
750 /**
751  * Look in the FDT for a config item with the given name and return its value
752  * as a string.
753  *
754  * @param blob          FDT blob
755  * @param prop_name     property name to look up
756  * @returns property string, NULL on error.
757  */
758 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
759 
760 /*
761  * Look up a property in a node and return its contents in a byte
762  * array of given length. The property must have at least enough data for
763  * the array (count bytes). It may have more, but this will be ignored.
764  *
765  * @param blob		FDT blob
766  * @param node		node to examine
767  * @param prop_name	name of property to find
768  * @param array		array to fill with data
769  * @param count		number of array elements
770  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
771  *		or -FDT_ERR_BADLAYOUT if not enough data
772  */
773 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
774 		u8 *array, int count);
775 
776 /**
777  * Look up a property in a node and return a pointer to its contents as a
778  * byte array of given length. The property must have at least enough data
779  * for the array (count bytes). It may have more, but this will be ignored.
780  * The data is not copied.
781  *
782  * @param blob		FDT blob
783  * @param node		node to examine
784  * @param prop_name	name of property to find
785  * @param count		number of array elements
786  * @return pointer to byte array if found, or NULL if the property is not
787  *		found or there is not enough data
788  */
789 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
790 			     const char *prop_name, int count);
791 
792 /**
793  * Look up a property in a node which contains a memory region address and
794  * size. Then return a pointer to this address.
795  *
796  * The property must hold one address with a length. This is only tested on
797  * 32-bit machines.
798  *
799  * @param blob		FDT blob
800  * @param node		node to examine
801  * @param prop_name	name of property to find
802  * @param basep		Returns base address of region
803  * @param size		Returns size of region
804  * @return 0 if ok, -1 on error (property not found)
805  */
806 int fdtdec_decode_region(const void *blob, int node, const char *prop_name,
807 			 fdt_addr_t *basep, fdt_size_t *sizep);
808 
809 enum fmap_compress_t {
810 	FMAP_COMPRESS_NONE,
811 	FMAP_COMPRESS_LZO,
812 };
813 
814 enum fmap_hash_t {
815 	FMAP_HASH_NONE,
816 	FMAP_HASH_SHA1,
817 	FMAP_HASH_SHA256,
818 };
819 
820 /* A flash map entry, containing an offset and length */
821 struct fmap_entry {
822 	uint32_t offset;
823 	uint32_t length;
824 	uint32_t used;			/* Number of bytes used in region */
825 	enum fmap_compress_t compress_algo;	/* Compression type */
826 	enum fmap_hash_t hash_algo;		/* Hash algorithm */
827 	const uint8_t *hash;			/* Hash value */
828 	int hash_size;				/* Hash size */
829 };
830 
831 /**
832  * Read a flash entry from the fdt
833  *
834  * @param blob		FDT blob
835  * @param node		Offset of node to read
836  * @param name		Name of node being read
837  * @param entry		Place to put offset and size of this node
838  * @return 0 if ok, -ve on error
839  */
840 int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
841 			   struct fmap_entry *entry);
842 
843 /**
844  * Obtain an indexed resource from a device property.
845  *
846  * @param fdt		FDT blob
847  * @param node		node to examine
848  * @param property	name of the property to parse
849  * @param index		index of the resource to retrieve
850  * @param res		returns the resource
851  * @return 0 if ok, negative on error
852  */
853 int fdt_get_resource(const void *fdt, int node, const char *property,
854 		     unsigned int index, struct fdt_resource *res);
855 
856 /**
857  * Obtain a named resource from a device property.
858  *
859  * Look up the index of the name in a list of strings and return the resource
860  * at that index.
861  *
862  * @param fdt		FDT blob
863  * @param node		node to examine
864  * @param property	name of the property to parse
865  * @param prop_names	name of the property containing the list of names
866  * @param name		the name of the entry to look up
867  * @param res		returns the resource
868  */
869 int fdt_get_named_resource(const void *fdt, int node, const char *property,
870 			   const char *prop_names, const char *name,
871 			   struct fdt_resource *res);
872 
873 /**
874  * Decode a named region within a memory bank of a given type.
875  *
876  * This function handles selection of a memory region. The region is
877  * specified as an offset/size within a particular type of memory.
878  *
879  * The properties used are:
880  *
881  *	<mem_type>-memory<suffix> for the name of the memory bank
882  *	<mem_type>-offset<suffix> for the offset in that bank
883  *
884  * The property value must have an offset and a size. The function checks
885  * that the region is entirely within the memory bank.5
886  *
887  * @param blob		FDT blob
888  * @param node		Node containing the properties (-1 for /config)
889  * @param mem_type	Type of memory to use, which is a name, such as
890  *			"u-boot" or "kernel".
891  * @param suffix	String to append to the memory/offset
892  *			property names
893  * @param basep		Returns base of region
894  * @param sizep		Returns size of region
895  * @return 0 if OK, -ive on error
896  */
897 int fdtdec_decode_memory_region(const void *blob, int node,
898 				const char *mem_type, const char *suffix,
899 				fdt_addr_t *basep, fdt_size_t *sizep);
900 
901 /* Display timings from linux include/video/display_timing.h */
902 enum display_flags {
903 	DISPLAY_FLAGS_HSYNC_LOW		= 1 << 0,
904 	DISPLAY_FLAGS_HSYNC_HIGH	= 1 << 1,
905 	DISPLAY_FLAGS_VSYNC_LOW		= 1 << 2,
906 	DISPLAY_FLAGS_VSYNC_HIGH	= 1 << 3,
907 
908 	/* data enable flag */
909 	DISPLAY_FLAGS_DE_LOW		= 1 << 4,
910 	DISPLAY_FLAGS_DE_HIGH		= 1 << 5,
911 	/* drive data on pos. edge */
912 	DISPLAY_FLAGS_PIXDATA_POSEDGE	= 1 << 6,
913 	/* drive data on neg. edge */
914 	DISPLAY_FLAGS_PIXDATA_NEGEDGE	= 1 << 7,
915 	DISPLAY_FLAGS_INTERLACED	= 1 << 8,
916 	DISPLAY_FLAGS_DOUBLESCAN	= 1 << 9,
917 	DISPLAY_FLAGS_DOUBLECLK		= 1 << 10,
918 };
919 
920 /*
921  * A single signal can be specified via a range of minimal and maximal values
922  * with a typical value, that lies somewhere inbetween.
923  */
924 struct timing_entry {
925 	u32 min;
926 	u32 typ;
927 	u32 max;
928 };
929 
930 /*
931  * Single "mode" entry. This describes one set of signal timings a display can
932  * have in one setting. This struct can later be converted to struct videomode
933  * (see include/video/videomode.h). As each timing_entry can be defined as a
934  * range, one struct display_timing may become multiple struct videomodes.
935  *
936  * Example: hsync active high, vsync active low
937  *
938  *				    Active Video
939  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
940  *	  |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
941  *	  |	     |	 porch  |		     |	 porch	 |
942  *
943  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
944  *
945  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
946  */
947 struct display_timing {
948 	struct timing_entry pixelclock;
949 
950 	struct timing_entry hactive;		/* hor. active video */
951 	struct timing_entry hfront_porch;	/* hor. front porch */
952 	struct timing_entry hback_porch;	/* hor. back porch */
953 	struct timing_entry hsync_len;		/* hor. sync len */
954 
955 	struct timing_entry vactive;		/* ver. active video */
956 	struct timing_entry vfront_porch;	/* ver. front porch */
957 	struct timing_entry vback_porch;	/* ver. back porch */
958 	struct timing_entry vsync_len;		/* ver. sync len */
959 
960 	enum display_flags flags;		/* display flags */
961 };
962 
963 /**
964  * fdtdec_decode_display_timing() - decode display timings
965  *
966  * Decode display timings from the supplied 'display-timings' node.
967  * See doc/device-tree-bindings/video/display-timing.txt for binding
968  * information.
969  *
970  * @param blob		FDT blob
971  * @param node		'display-timing' node containing the timing subnodes
972  * @param index		Index number to read (0=first timing subnode)
973  * @param config	Place to put timings
974  * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
975  */
976 int fdtdec_decode_display_timing(const void *blob, int node, int index,
977 				 struct display_timing *config);
978 /**
979  * Set up the device tree ready for use
980  */
981 int fdtdec_setup(void);
982 
983 #endif
984