include/fdtdec.h - github/trini/u-boot - Gitiles

 /*
  * Copyright (c) 2011 The Chromium OS Authors.
  * See file CREDITS for list of people who contributed to this
  * project.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  * MA 02111-1307 USA
  */

 #ifndef __fdtdec_h
 #define __fdtdec_h

 /*
  * This file contains convenience functions for decoding useful and
  * enlightening information from FDTs. It is intended to be used by device
  * drivers and board-specific code within U-Boot. It aims to reduce the
  * amount of FDT munging required within U-Boot itself, so that driver code
  * changes to support FDT are minimized.
  */

 #include <libfdt.h>

 /*
  * A typedef for a physical address. Note that fdt data is always big
  * endian even on a litle endian machine.
  */
 #ifdef CONFIG_PHYS_64BIT
 typedef u64 fdt_addr_t;
 #define FDT_ADDR_T_NONE (-1ULL)
 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
 #else
 typedef u32 fdt_addr_t;
 #define FDT_ADDR_T_NONE (-1U)
 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
 #endif

 /* Information obtained about memory from the FDT */
 struct fdt_memory {
 	fdt_addr_t start;
 	fdt_addr_t end;
 };

 /**
  * Compat types that we know about and for which we might have drivers.
  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
  * within drivers.
  */
 enum fdt_compat_id {
 	COMPAT_UNKNOWN,
 	COMPAT_NVIDIA_TEGRA20_USB,	/* Tegra20 USB port */
 	COMPAT_NVIDIA_TEGRA114_I2C,	/* Tegra114 I2C w/single clock source */
 	COMPAT_NVIDIA_TEGRA20_I2C,	/* Tegra20 i2c */
 	COMPAT_NVIDIA_TEGRA20_DVC,	/* Tegra20 dvc (really just i2c) */
 	COMPAT_NVIDIA_TEGRA20_EMC,	/* Tegra20 memory controller */
 	COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
 	COMPAT_NVIDIA_TEGRA20_KBC,	/* Tegra20 Keyboard */
 	COMPAT_NVIDIA_TEGRA20_NAND,	/* Tegra2 NAND controller */
 	COMPAT_NVIDIA_TEGRA20_PWM,	/* Tegra 2 PWM controller */
 	COMPAT_NVIDIA_TEGRA20_DC,	/* Tegra 2 Display controller */
 	COMPAT_NVIDIA_TEGRA30_SDMMC,	/* Tegra30 SDMMC controller */
 	COMPAT_NVIDIA_TEGRA20_SDMMC,	/* Tegra20 SDMMC controller */
 	COMPAT_NVIDIA_TEGRA20_SFLASH,	/* Tegra 2 SPI flash controller */
 	COMPAT_NVIDIA_TEGRA20_SLINK,	/* Tegra 2 SPI SLINK controller */
 	COMPAT_SMSC_LAN9215,		/* SMSC 10/100 Ethernet LAN9215 */
 	COMPAT_SAMSUNG_EXYNOS5_SROMC,	/* Exynos5 SROMC */
 	COMPAT_SAMSUNG_S3C2440_I2C,	/* Exynos I2C Controller */
 	COMPAT_SAMSUNG_EXYNOS5_SOUND,	/* Exynos Sound */
 	COMPAT_WOLFSON_WM8994_CODEC,	/* Wolfson WM8994 Sound Codec */
 	COMPAT_SAMSUNG_EXYNOS_SPI,	/* Exynos SPI */
 	COMPAT_SAMSUNG_EXYNOS_EHCI,	/* Exynos EHCI controller */
 	COMPAT_SAMSUNG_EXYNOS_USB_PHY,	/* Exynos phy controller for usb2.0 */
 	COMPAT_MAXIM_MAX77686_PMIC,	/* MAX77686 PMIC */

 	COMPAT_COUNT,
 };

 /* GPIOs are numbered from 0 */
 enum {
 	FDT_GPIO_NONE = -1U,	/* an invalid GPIO used to end our list */

 	FDT_GPIO_ACTIVE_LOW = 1 << 0,	/* input is active low (else high) */
 };

 /* This is the state of a GPIO pin as defined by the fdt */
 struct fdt_gpio_state {
 	const char *name;	/* name of the fdt property defining this */
 	uint gpio;		/* GPIO number, or FDT_GPIO_NONE if none */
 	u8 flags;		/* FDT_GPIO_... flags */
 };

 /* This tells us whether a fdt_gpio_state record is valid or not */
 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)

 /**
  * Read the GPIO taking into account the polarity of the pin.
  *
  * @param gpio		pointer to the decoded gpio
  * @return value of the gpio if successful, < 0 if unsuccessful
  */
 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);

 /**
  * Write the GPIO taking into account the polarity of the pin.
  *
  * @param gpio		pointer to the decoded gpio
  * @return 0 if successful
  */
 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);

 /**
  * Find the next numbered alias for a peripheral. This is used to enumerate
  * all the peripherals of a certain type.
  *
  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
  * this function will return a pointer to the node the alias points to, and
  * then update *upto to 1. Next time you call this function, the next node
  * will be returned.
  *
  * All nodes returned will match the compatible ID, as it is assumed that
  * all peripherals use the same driver.
  *
  * @param blob		FDT blob to use
  * @param name		Root name of alias to search for
  * @param id		Compatible ID to look for
  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  */
 int fdtdec_next_alias(const void *blob, const char *name,
 		enum fdt_compat_id id, int *upto);

 /**
  * Find the compatible ID for a given node.
  *
  * Generally each node has at least one compatible string attached to it.
  * This function looks through our list of known compatible strings and
  * returns the corresponding ID which matches the compatible string.
  *
  * @param blob		FDT blob to use
  * @param node		Node containing compatible string to find
  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
  */
 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);

 /**
  * Find the next compatible node for a peripheral.
  *
  * Do the first call with node = 0. This function will return a pointer to
  * the next compatible node. Next time you call this function, pass the
  * value returned, and the next node will be provided.
  *
  * @param blob		FDT blob to use
  * @param node		Start node for search
  * @param id		Compatible ID to look for (enum fdt_compat_id)
  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  */
 int fdtdec_next_compatible(const void *blob, int node,
 		enum fdt_compat_id id);

 /**
  * Find the next compatible subnode for a peripheral.
  *
  * Do the first call with node set to the parent and depth = 0. This
  * function will return the offset of the next compatible node. Next time
  * you call this function, pass the node value returned last time, with
  * depth unchanged, and the next node will be provided.
  *
  * @param blob		FDT blob to use
  * @param node		Start node for search
  * @param id		Compatible ID to look for (enum fdt_compat_id)
  * @param depthp	Current depth (set to 0 before first call)
  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  */
 int fdtdec_next_compatible_subnode(const void *blob, int node,
 		enum fdt_compat_id id, int *depthp);

 /**
  * Look up an address property in a node and return it as an address.
  * The property must hold either one address with no trailing data or
  * one address with a length. This is only tested on 32-bit machines.
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @param prop_name	name of property to find
  * @return address, if found, or FDT_ADDR_T_NONE if not
  */
 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
 		const char *prop_name);

 /**
  * Look up a 32-bit integer property in a node and return it. The property
  * must have at least 4 bytes of data. The value of the first cell is
  * returned.
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @param prop_name	name of property to find
  * @param default_val	default value to return if the property is not found
  * @return integer value, if found, or default_val if not
  */
 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
 		s32 default_val);

 /**
  * Look up a 64-bit integer property in a node and return it. The property
  * must have at least 8 bytes of data (2 cells). The first two cells are
  * concatenated to form a 8 bytes value, where the first cell is top half and
  * the second cell is bottom half.
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @param prop_name	name of property to find
  * @param default_val	default value to return if the property is not found
  * @return integer value, if found, or default_val if not
  */
 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
 		uint64_t default_val);

 /**
  * Checks whether a node is enabled.
  * This looks for a 'status' property. If this exists, then returns 1 if
  * the status is 'ok' and 0 otherwise. If there is no status property,
  * it returns 1 on the assumption that anything mentioned should be enabled
  * by default.
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @return integer value 0 (not enabled) or 1 (enabled)
  */
 int fdtdec_get_is_enabled(const void *blob, int node);

 /**
  * Make sure we have a valid fdt available to control U-Boot.
  *
  * If not, a message is printed to the console if the console is ready.
  *
  * @return 0 if all ok, -1 if not
  */
 int fdtdec_prepare_fdt(void);

 /**
  * Checks that we have a valid fdt available to control U-Boot.

  * However, if not then for the moment nothing is done, since this function
  * is called too early to panic().
  *
  * @returns 0
  */
 int fdtdec_check_fdt(void);

 /**
  * Find the nodes for a peripheral and return a list of them in the correct
  * order. This is used to enumerate all the peripherals of a certain type.
  *
  * To use this, optionally set up a /aliases node with alias properties for
  * a peripheral. For example, for usb you could have:
  *
  * aliases {
  *		usb0 = "/ehci@c5008000";
  *		usb1 = "/ehci@c5000000";
  * };
  *
  * Pass "usb" as the name to this function and will return a list of two
  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
  *
  * All nodes returned will match the compatible ID, as it is assumed that
  * all peripherals use the same driver.
  *
  * If no alias node is found, then the node list will be returned in the
  * order found in the fdt. If the aliases mention a node which doesn't
  * exist, then this will be ignored. If nodes are found with no aliases,
  * they will be added in any order.
  *
  * If there is a gap in the aliases, then this function return a 0 node at
  * that position. The return value will also count these gaps.
  *
  * This function checks node properties and will not return nodes which are
  * marked disabled (status = "disabled").
  *
  * @param blob		FDT blob to use
  * @param name		Root name of alias to search for
  * @param id		Compatible ID to look for
  * @param node_list	Place to put list of found nodes
  * @param maxcount	Maximum number of nodes to find
  * @return number of nodes found on success, FTD_ERR_... on error
  */
 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
 			enum fdt_compat_id id, int *node_list, int maxcount);

 /*
  * This function is similar to fdtdec_find_aliases_for_id() except that it
  * adds to the node_list that is passed in. Any 0 elements are considered
  * available for allocation - others are considered already used and are
  * skipped.
  *
  * You can use this by calling fdtdec_find_aliases_for_id() with an
  * uninitialised array, then setting the elements that are returned to -1,
  * say, then calling this function, perhaps with a different compat id.
  * Any elements you get back that are >0 are new nodes added by the call
  * to this function.
  *
  * Note that if you have some nodes with aliases and some without, you are
  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
  * one compat_id may fill in positions for which you have aliases defined
  * for another compat_id. When you later call *this* function with the second
  * compat_id, the alias positions may already be used. A debug warning may
  * be generated in this case, but it is safest to define aliases for all
  * nodes when you care about the ordering.
  */
 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
 			enum fdt_compat_id id, int *node_list, int maxcount);

 /*
  * Get the name for a compatible ID
  *
  * @param id		Compatible ID to look for
  * @return compatible string for that id
  */
 const char *fdtdec_get_compatible(enum fdt_compat_id id);

 /* Look up a phandle and follow it to its node. Then return the offset
  * of that node.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @return node offset if found, -ve error code on error
  */
 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);

 /**
  * Look up a property in a node and return its contents in an integer
  * array of given length. The property must have at least enough data for
  * the array (4*count bytes). It may have more, but this will be ignored.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @param array		array to fill with data
  * @param count		number of array elements
  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
  *		or -FDT_ERR_BADLAYOUT if not enough data
  */
 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
 		u32 *array, int count);

 /**
  * Look up a property in a node and return a pointer to its contents as a
  * unsigned int array of given length. The property must have at least enough
  * data for the array ('count' cells). It may have more, but this will be
  * ignored. The data is not copied.
  *
  * Note that you must access elements of the array with fdt32_to_cpu(),
  * since the elements will be big endian even on a little endian machine.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @param count		number of array elements
  * @return pointer to array if found, or NULL if the property is not
  *		found or there is not enough data
  */
 const u32 *fdtdec_locate_array(const void *blob, int node,
 			       const char *prop_name, int count);

 /**
  * Look up a boolean property in a node and return it.
  *
  * A boolean properly is true if present in the device tree and false if not
  * present, regardless of its value.
  *
  * @param blob	FDT blob
  * @param node	node to examine
  * @param prop_name	name of property to find
  * @return 1 if the properly is present; 0 if it isn't present
  */
 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);

 /**
  * Decode a single GPIOs from an FDT.
  *
  * If the property is not found, then the GPIO structure will still be
  * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
  * provide optional GPIOs.
  *
  * @param blob		FDT blob to use
  * @param node		Node to look at
  * @param prop_name	Node property name
  * @param gpio		gpio elements to fill from FDT
  * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
  */
 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
 		struct fdt_gpio_state *gpio);

 /**
  * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
  * terminating item.
  *
  * @param blob         FDT blob to use
  * @param node         Node to look at
  * @param prop_name    Node property name
  * @param gpio         Array of gpio elements to fill from FDT. This will be
  *                     untouched if either 0 or an error is returned
  * @param max_count    Maximum number of elements allowed
  * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
  * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
  */
 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
 		struct fdt_gpio_state *gpio, int max_count);

 /**
  * Set up a GPIO pin according to the provided gpio information. At present this
  * just requests the GPIO.
  *
  * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
  * deal with optional GPIOs.
  *
  * @param gpio		GPIO info to use for set up
  * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
  */
 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);

 /**
  * Look in the FDT for a config item with the given name and return its value
  * as a 32-bit integer. The property must have at least 4 bytes of data. The
  * value of the first cell is returned.
  *
  * @param blob		FDT blob to use
  * @param prop_name	Node property name
  * @param default_val	default value to return if the property is not found
  * @return integer value, if found, or default_val if not
  */
 int fdtdec_get_config_int(const void *blob, const char *prop_name,
 		int default_val);

 /**
  * Look in the FDT for a config item with the given name
  * and return whether it exists.
  *
  * @param blob		FDT blob
  * @param prop_name	property name to look up
  * @return 1, if it exists, or 0 if not
  */
 int fdtdec_get_config_bool(const void *blob, const char *prop_name);

 /**
  * Look in the FDT for a config item with the given name and return its value
  * as a string.
  *
  * @param blob          FDT blob
  * @param prop_name     property name to look up
  * @returns property string, NULL on error.
  */
 char *fdtdec_get_config_string(const void *blob, const char *prop_name);

 /*
  * Look up a property in a node and return its contents in a byte
  * array of given length. The property must have at least enough data for
  * the array (count bytes). It may have more, but this will be ignored.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @param array		array to fill with data
  * @param count		number of array elements
  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
  *		or -FDT_ERR_BADLAYOUT if not enough data
  */
 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
 		u8 *array, int count);

 /**
  * Look up a property in a node and return a pointer to its contents as a
  * byte array of given length. The property must have at least enough data
  * for the array (count bytes). It may have more, but this will be ignored.
  * The data is not copied.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @param count		number of array elements
  * @return pointer to byte array if found, or NULL if the property is not
  *		found or there is not enough data
  */
 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
 			     const char *prop_name, int count);

 /**
  * Look up a property in a node which contains a memory region address and
  * size. Then return a pointer to this address.
  *
  * The property must hold one address with a length. This is only tested on
  * 32-bit machines.
  *
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
  * @param ptrp		returns pointer to region, or NULL if no address
  * @param size		returns size of region
  * @return 0 if ok, -1 on error (propery not found)
  */
 int fdtdec_decode_region(const void *blob, int node,
 		const char *prop_name, void **ptrp, size_t *size);
 #endif
	/*
	* Copyright (c) 2011 The Chromium OS Authors.
	* See file CREDITS for list of people who contributed to this
	* project.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation; either version 2 of
	* the License, or (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	* MA 02111-1307 USA
	*/

	#ifndef __fdtdec_h
	#define __fdtdec_h

	/*
	* This file contains convenience functions for decoding useful and
	* enlightening information from FDTs. It is intended to be used by device
	* drivers and board-specific code within U-Boot. It aims to reduce the
	* amount of FDT munging required within U-Boot itself, so that driver code
	* changes to support FDT are minimized.
	*/

	#include <libfdt.h>

	/*
	* A typedef for a physical address. Note that fdt data is always big
	* endian even on a litle endian machine.
	*/
	#ifdef CONFIG_PHYS_64BIT
	typedef u64 fdt_addr_t;
	#define FDT_ADDR_T_NONE (-1ULL)
	#define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
	#define fdt_size_to_cpu(reg) be64_to_cpu(reg)
	#else
	typedef u32 fdt_addr_t;
	#define FDT_ADDR_T_NONE (-1U)
	#define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
	#define fdt_size_to_cpu(reg) be32_to_cpu(reg)
	#endif

	/* Information obtained about memory from the FDT */
	struct fdt_memory {
	fdt_addr_t start;
	fdt_addr_t end;
	};

	/**
	* Compat types that we know about and for which we might have drivers.
	* Each is named COMPAT_<dir>_<filename> where <dir> is the directory
	* within drivers.
	*/
	enum fdt_compat_id {
	COMPAT_UNKNOWN,
	COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */
	COMPAT_NVIDIA_TEGRA114_I2C, /* Tegra114 I2C w/single clock source */
	COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */
	COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */
	COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */
	COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
	COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */
	COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */
	COMPAT_NVIDIA_TEGRA20_PWM, /* Tegra 2 PWM controller */
	COMPAT_NVIDIA_TEGRA20_DC, /* Tegra 2 Display controller */
	COMPAT_NVIDIA_TEGRA30_SDMMC, /* Tegra30 SDMMC controller */
	COMPAT_NVIDIA_TEGRA20_SDMMC, /* Tegra20 SDMMC controller */
	COMPAT_NVIDIA_TEGRA20_SFLASH, /* Tegra 2 SPI flash controller */
	COMPAT_NVIDIA_TEGRA20_SLINK, /* Tegra 2 SPI SLINK controller */
	COMPAT_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */
	COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */
	COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */
	COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */
	COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */
	COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */
	COMPAT_SAMSUNG_EXYNOS_EHCI, /* Exynos EHCI controller */
	COMPAT_SAMSUNG_EXYNOS_USB_PHY, /* Exynos phy controller for usb2.0 */
	COMPAT_MAXIM_MAX77686_PMIC, /* MAX77686 PMIC */

	COMPAT_COUNT,
	};

	/* GPIOs are numbered from 0 */
	enum {
	FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */

	FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
	};

	/* This is the state of a GPIO pin as defined by the fdt */
	struct fdt_gpio_state {
	const char name; / name of the fdt property defining this */
	uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
	u8 flags; /* FDT_GPIO_... flags */
	};

	/* This tells us whether a fdt_gpio_state record is valid or not */
	#define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)

	/**
	* Read the GPIO taking into account the polarity of the pin.
	*
	* @param gpio pointer to the decoded gpio
	* @return value of the gpio if successful, < 0 if unsuccessful
	*/
	int fdtdec_get_gpio(struct fdt_gpio_state *gpio);

	/**
	* Write the GPIO taking into account the polarity of the pin.
	*
	* @param gpio pointer to the decoded gpio
	* @return 0 if successful
	*/
	int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);

	/**
	* Find the next numbered alias for a peripheral. This is used to enumerate
	* all the peripherals of a certain type.
	*
	* Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
	* this function will return a pointer to the node the alias points to, and
	* then update *upto to 1. Next time you call this function, the next node
	* will be returned.
	*
	* All nodes returned will match the compatible ID, as it is assumed that
	* all peripherals use the same driver.
	*
	* @param blob FDT blob to use
	* @param name Root name of alias to search for
	* @param id Compatible ID to look for
	* @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
	*/
	int fdtdec_next_alias(const void blob, const char name,
	enum fdt_compat_id id, int *upto);

	/**
	* Find the compatible ID for a given node.
	*
	* Generally each node has at least one compatible string attached to it.
	* This function looks through our list of known compatible strings and
	* returns the corresponding ID which matches the compatible string.
	*
	* @param blob FDT blob to use
	* @param node Node containing compatible string to find
	* @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
	*/
	enum fdt_compat_id fdtdec_lookup(const void *blob, int node);

	/**
	* Find the next compatible node for a peripheral.
	*
	* Do the first call with node = 0. This function will return a pointer to
	* the next compatible node. Next time you call this function, pass the
	* value returned, and the next node will be provided.
	*
	* @param blob FDT blob to use
	* @param node Start node for search
	* @param id Compatible ID to look for (enum fdt_compat_id)
	* @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
	*/
	int fdtdec_next_compatible(const void *blob, int node,
	enum fdt_compat_id id);

	/**
	* Find the next compatible subnode for a peripheral.
	*
	* Do the first call with node set to the parent and depth = 0. This
	* function will return the offset of the next compatible node. Next time
	* you call this function, pass the node value returned last time, with
	* depth unchanged, and the next node will be provided.
	*
	* @param blob FDT blob to use
	* @param node Start node for search
	* @param id Compatible ID to look for (enum fdt_compat_id)
	* @param depthp Current depth (set to 0 before first call)
	* @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
	*/
	int fdtdec_next_compatible_subnode(const void *blob, int node,
	enum fdt_compat_id id, int *depthp);

	/**
	* Look up an address property in a node and return it as an address.
	* The property must hold either one address with no trailing data or
	* one address with a length. This is only tested on 32-bit machines.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @return address, if found, or FDT_ADDR_T_NONE if not
	*/
	fdt_addr_t fdtdec_get_addr(const void *blob, int node,
	const char *prop_name);

	/**
	* Look up a 32-bit integer property in a node and return it. The property
	* must have at least 4 bytes of data. The value of the first cell is
	* returned.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param default_val default value to return if the property is not found
	* @return integer value, if found, or default_val if not
	*/
	s32 fdtdec_get_int(const void blob, int node, const char prop_name,
	s32 default_val);

	/**
	* Look up a 64-bit integer property in a node and return it. The property
	* must have at least 8 bytes of data (2 cells). The first two cells are
	* concatenated to form a 8 bytes value, where the first cell is top half and
	* the second cell is bottom half.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param default_val default value to return if the property is not found
	* @return integer value, if found, or default_val if not
	*/
	uint64_t fdtdec_get_uint64(const void blob, int node, const char prop_name,
	uint64_t default_val);

	/**
	* Checks whether a node is enabled.
	* This looks for a 'status' property. If this exists, then returns 1 if
	* the status is 'ok' and 0 otherwise. If there is no status property,
	* it returns 1 on the assumption that anything mentioned should be enabled
	* by default.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @return integer value 0 (not enabled) or 1 (enabled)
	*/
	int fdtdec_get_is_enabled(const void *blob, int node);

	/**
	* Make sure we have a valid fdt available to control U-Boot.
	*
	* If not, a message is printed to the console if the console is ready.
	*
	* @return 0 if all ok, -1 if not
	*/
	int fdtdec_prepare_fdt(void);

	/**
	* Checks that we have a valid fdt available to control U-Boot.

	* However, if not then for the moment nothing is done, since this function
	* is called too early to panic().
	*
	* @returns 0
	*/
	int fdtdec_check_fdt(void);

	/**
	* Find the nodes for a peripheral and return a list of them in the correct
	* order. This is used to enumerate all the peripherals of a certain type.
	*
	* To use this, optionally set up a /aliases node with alias properties for
	* a peripheral. For example, for usb you could have:
	*
	* aliases {
	* usb0 = "/ehci@c5008000";
	* usb1 = "/ehci@c5000000";
	* };
	*
	* Pass "usb" as the name to this function and will return a list of two
	* nodes offsets: /ehci@c5008000 and ehci@c5000000.
	*
	* All nodes returned will match the compatible ID, as it is assumed that
	* all peripherals use the same driver.
	*
	* If no alias node is found, then the node list will be returned in the
	* order found in the fdt. If the aliases mention a node which doesn't
	* exist, then this will be ignored. If nodes are found with no aliases,
	* they will be added in any order.
	*
	* If there is a gap in the aliases, then this function return a 0 node at
	* that position. The return value will also count these gaps.
	*
	* This function checks node properties and will not return nodes which are
	* marked disabled (status = "disabled").
	*
	* @param blob FDT blob to use
	* @param name Root name of alias to search for
	* @param id Compatible ID to look for
	* @param node_list Place to put list of found nodes
	* @param maxcount Maximum number of nodes to find
	* @return number of nodes found on success, FTD_ERR_... on error
	*/
	int fdtdec_find_aliases_for_id(const void blob, const char name,
	enum fdt_compat_id id, int *node_list, int maxcount);

	/*
	* This function is similar to fdtdec_find_aliases_for_id() except that it
	* adds to the node_list that is passed in. Any 0 elements are considered
	* available for allocation - others are considered already used and are
	* skipped.
	*
	* You can use this by calling fdtdec_find_aliases_for_id() with an
	* uninitialised array, then setting the elements that are returned to -1,
	* say, then calling this function, perhaps with a different compat id.
	* Any elements you get back that are >0 are new nodes added by the call
	* to this function.
	*
	* Note that if you have some nodes with aliases and some without, you are
	* sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
	* one compat_id may fill in positions for which you have aliases defined
	* for another compat_id. When you later call this function with the second
	* compat_id, the alias positions may already be used. A debug warning may
	* be generated in this case, but it is safest to define aliases for all
	* nodes when you care about the ordering.
	*/
	int fdtdec_add_aliases_for_id(const void blob, const char name,
	enum fdt_compat_id id, int *node_list, int maxcount);

	/*
	* Get the name for a compatible ID
	*
	* @param id Compatible ID to look for
	* @return compatible string for that id
	*/
	const char *fdtdec_get_compatible(enum fdt_compat_id id);

	/* Look up a phandle and follow it to its node. Then return the offset
	* of that node.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @return node offset if found, -ve error code on error
	*/
	int fdtdec_lookup_phandle(const void blob, int node, const char prop_name);

	/**
	* Look up a property in a node and return its contents in an integer
	* array of given length. The property must have at least enough data for
	* the array (4*count bytes). It may have more, but this will be ignored.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param array array to fill with data
	* @param count number of array elements
	* @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
	* or -FDT_ERR_BADLAYOUT if not enough data
	*/
	int fdtdec_get_int_array(const void blob, int node, const char prop_name,
	u32 *array, int count);

	/**
	* Look up a property in a node and return a pointer to its contents as a
	* unsigned int array of given length. The property must have at least enough
	* data for the array ('count' cells). It may have more, but this will be
	* ignored. The data is not copied.
	*
	* Note that you must access elements of the array with fdt32_to_cpu(),
	* since the elements will be big endian even on a little endian machine.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param count number of array elements
	* @return pointer to array if found, or NULL if the property is not
	* found or there is not enough data
	*/
	const u32 fdtdec_locate_array(const void blob, int node,
	const char *prop_name, int count);

	/**
	* Look up a boolean property in a node and return it.
	*
	* A boolean properly is true if present in the device tree and false if not
	* present, regardless of its value.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @return 1 if the properly is present; 0 if it isn't present
	*/
	int fdtdec_get_bool(const void blob, int node, const char prop_name);

	/**
	* Decode a single GPIOs from an FDT.
	*
	* If the property is not found, then the GPIO structure will still be
	* initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
	* provide optional GPIOs.
	*
	* @param blob FDT blob to use
	* @param node Node to look at
	* @param prop_name Node property name
	* @param gpio gpio elements to fill from FDT
	* @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
	*/
	int fdtdec_decode_gpio(const void blob, int node, const char prop_name,
	struct fdt_gpio_state *gpio);

	/**
	* Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
	* terminating item.
	*
	* @param blob FDT blob to use
	* @param node Node to look at
	* @param prop_name Node property name
	* @param gpio Array of gpio elements to fill from FDT. This will be
	* untouched if either 0 or an error is returned
	* @param max_count Maximum number of elements allowed
	* @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
	* be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
	*/
	int fdtdec_decode_gpios(const void blob, int node, const char prop_name,
	struct fdt_gpio_state *gpio, int max_count);

	/**
	* Set up a GPIO pin according to the provided gpio information. At present this
	* just requests the GPIO.
	*
	* If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
	* deal with optional GPIOs.
	*
	* @param gpio GPIO info to use for set up
	* @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
	*/
	int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);

	/**
	* Look in the FDT for a config item with the given name and return its value
	* as a 32-bit integer. The property must have at least 4 bytes of data. The
	* value of the first cell is returned.
	*
	* @param blob FDT blob to use
	* @param prop_name Node property name
	* @param default_val default value to return if the property is not found
	* @return integer value, if found, or default_val if not
	*/
	int fdtdec_get_config_int(const void blob, const char prop_name,
	int default_val);

	/**
	* Look in the FDT for a config item with the given name
	* and return whether it exists.
	*
	* @param blob FDT blob
	* @param prop_name property name to look up
	* @return 1, if it exists, or 0 if not
	*/
	int fdtdec_get_config_bool(const void blob, const char prop_name);

	/**
	* Look in the FDT for a config item with the given name and return its value
	* as a string.
	*
	* @param blob FDT blob
	* @param prop_name property name to look up
	* @returns property string, NULL on error.
	*/
	char fdtdec_get_config_string(const void blob, const char *prop_name);

	/*
	* Look up a property in a node and return its contents in a byte
	* array of given length. The property must have at least enough data for
	* the array (count bytes). It may have more, but this will be ignored.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param array array to fill with data
	* @param count number of array elements
	* @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
	* or -FDT_ERR_BADLAYOUT if not enough data
	*/
	int fdtdec_get_byte_array(const void blob, int node, const char prop_name,
	u8 *array, int count);

	/**
	* Look up a property in a node and return a pointer to its contents as a
	* byte array of given length. The property must have at least enough data
	* for the array (count bytes). It may have more, but this will be ignored.
	* The data is not copied.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param count number of array elements
	* @return pointer to byte array if found, or NULL if the property is not
	* found or there is not enough data
	*/
	const u8 fdtdec_locate_byte_array(const void blob, int node,
	const char *prop_name, int count);

	/**
	* Look up a property in a node which contains a memory region address and
	* size. Then return a pointer to this address.
	*
	* The property must hold one address with a length. This is only tested on
	* 32-bit machines.
	*
	* @param blob FDT blob
	* @param node node to examine
	* @param prop_name name of property to find
	* @param ptrp returns pointer to region, or NULL if no address
	* @param size returns size of region
	* @return 0 if ok, -1 on error (propery not found)
	*/
	int fdtdec_decode_region(const void *blob, int node,
	const char prop_name, void ptrp, size_t size);
	#endif