[oweals/u-boot.git] / include / fdtdec.h

/*
 * Copyright (c) 2011 The Chromium OS Authors.
 * SPDX-License-Identifier:     GPL-2.0+
 */

#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>
#include <pci.h>

/*
 * A typedef for a physical address. Note that fdt data is always big
 * endian even on a litle endian machine.
 */
typedef phys_addr_t fdt_addr_t;
typedef phys_size_t fdt_size_t;
#ifdef CONFIG_PHYS_64BIT
#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
#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;
};

#ifdef CONFIG_SPL_BUILD
#define SPL_BUILD       1
#else
#define SPL_BUILD       0
#endif

/*
 * Information about a resource. start is the first address of the resource
 * and end is the last address (inclusive). The length of the resource will
 * be equal to: end - start + 1.
 */
struct fdt_resource {
        fdt_addr_t start;
        fdt_addr_t end;
};

enum fdt_pci_space {
        FDT_PCI_SPACE_CONFIG = 0,
        FDT_PCI_SPACE_IO = 0x01000000,
        FDT_PCI_SPACE_MEM32 = 0x02000000,
        FDT_PCI_SPACE_MEM64 = 0x03000000,
        FDT_PCI_SPACE_MEM32_PREF = 0x42000000,
        FDT_PCI_SPACE_MEM64_PREF = 0x43000000,
};

#define FDT_PCI_ADDR_CELLS      3
#define FDT_PCI_SIZE_CELLS      2
#define FDT_PCI_REG_SIZE        \
        ((FDT_PCI_ADDR_CELLS + FDT_PCI_SIZE_CELLS) * sizeof(u32))

/*
 * The Open Firmware spec defines PCI physical address as follows:
 *
 *          bits# 31 .... 24 23 .... 16 15 .... 08 07 .... 00
 *
 * phys.hi  cell:  npt000ss   bbbbbbbb   dddddfff   rrrrrrrr
 * phys.mid cell:  hhhhhhhh   hhhhhhhh   hhhhhhhh   hhhhhhhh
 * phys.lo  cell:  llllllll   llllllll   llllllll   llllllll
 *
 * where:
 *
 * n:        is 0 if the address is relocatable, 1 otherwise
 * p:        is 1 if addressable region is prefetchable, 0 otherwise
 * t:        is 1 if the address is aliased (for non-relocatable I/O) below 1MB
 *           (for Memory), or below 64KB (for relocatable I/O)
 * ss:       is the space code, denoting the address space
 * bbbbbbbb: is the 8-bit Bus Number
 * ddddd:    is the 5-bit Device Number
 * fff:      is the 3-bit Function Number
 * rrrrrrrr: is the 8-bit Register Number
 * hhhhhhhh: is a 32-bit unsigned number
 * llllllll: is a 32-bit unsigned number
 */
struct fdt_pci_addr {
        u32     phys_hi;
        u32     phys_mid;
        u32     phys_lo;
};

/**
 * Compute the size of a resource.
 *
 * @param res   the resource to operate on
 * @return the size of the resource
 */
static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
{
        return res->end - res->start + 1;
}

/**
 * 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_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_TEGRA124_DC,      /* Tegra 124 Display controller */
        COMPAT_NVIDIA_TEGRA124_SOR,     /* Tegra 124 Serial Output Resource */
        COMPAT_NVIDIA_TEGRA124_PMC,     /* Tegra 124 power mgmt controller */
        COMPAT_NVIDIA_TEGRA20_DC,       /* Tegra 2 Display controller */
        COMPAT_NVIDIA_TEGRA210_SDMMC,   /* Tegra210 SDMMC controller */
        COMPAT_NVIDIA_TEGRA124_SDMMC,   /* Tegra124 SDMMC controller */
        COMPAT_NVIDIA_TEGRA30_SDMMC,    /* Tegra30 SDMMC controller */
        COMPAT_NVIDIA_TEGRA20_SDMMC,    /* Tegra20 SDMMC controller */
        COMPAT_NVIDIA_TEGRA124_PCIE,    /* Tegra 124 PCIe controller */
        COMPAT_NVIDIA_TEGRA30_PCIE,     /* Tegra 30 PCIe controller */
        COMPAT_NVIDIA_TEGRA20_PCIE,     /* Tegra 20 PCIe controller */
        COMPAT_NVIDIA_TEGRA124_XUSB_PADCTL,
                                        /* Tegra124 XUSB pad controller */
        COMPAT_NVIDIA_TEGRA210_XUSB_PADCTL,
                                        /* Tegra210 XUSB pad 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_GOOGLE_CROS_EC_KEYB,     /* Google CROS_EC Keyboard */
        COMPAT_SAMSUNG_EXYNOS_USB_PHY,  /* Exynos phy controller for usb2.0 */
        COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
        COMPAT_SAMSUNG_EXYNOS_TMU,      /* Exynos TMU */
        COMPAT_SAMSUNG_EXYNOS_FIMD,     /* Exynos Display controller */
        COMPAT_SAMSUNG_EXYNOS_MIPI_DSI, /* Exynos mipi dsi */
        COMPAT_SAMSUNG_EXYNOS5_DP,      /* Exynos Display port controller */
        COMPAT_SAMSUNG_EXYNOS_DWMMC,    /* Exynos DWMMC controller */
        COMPAT_SAMSUNG_EXYNOS_MMC,      /* Exynos MMC controller */
        COMPAT_SAMSUNG_EXYNOS_SERIAL,   /* Exynos UART */
        COMPAT_MAXIM_MAX77686_PMIC,     /* MAX77686 PMIC */
        COMPAT_GENERIC_SPI_FLASH,       /* Generic SPI Flash chip */
        COMPAT_MAXIM_98095_CODEC,       /* MAX98095 Codec */
        COMPAT_SAMSUNG_EXYNOS5_I2C,     /* Exynos5 High Speed I2C Controller */
        COMPAT_SANDBOX_LCD_SDL,         /* Sandbox LCD emulation with SDL */
        COMPAT_SAMSUNG_EXYNOS_SYSMMU,   /* Exynos sysmmu */
        COMPAT_INTEL_MICROCODE,         /* Intel microcode update */
        COMPAT_MEMORY_SPD,              /* Memory SPD information */
        COMPAT_INTEL_PANTHERPOINT_AHCI, /* Intel Pantherpoint AHCI */
        COMPAT_INTEL_MODEL_206AX,       /* Intel Model 206AX CPU */
        COMPAT_INTEL_GMA,               /* Intel Graphics Media Accelerator */
        COMPAT_AMS_AS3722,              /* AMS AS3722 PMIC */
        COMPAT_INTEL_ICH_SPI,           /* Intel ICH7/9 SPI controller */
        COMPAT_INTEL_QRK_MRC,           /* Intel Quark MRC */
        COMPAT_INTEL_X86_PINCTRL,       /* Intel ICH7/9 pin control */
        COMPAT_SOCIONEXT_XHCI,          /* Socionext UniPhier xHCI */
        COMPAT_INTEL_PCH,               /* Intel PCH */
        COMPAT_INTEL_IRQ_ROUTER,        /* Intel Interrupt Router */
        COMPAT_ALTERA_SOCFPGA_DWMAC,    /* SoCFPGA Ethernet controller */
        COMPAT_ALTERA_SOCFPGA_DWMMC,    /* SoCFPGA DWMMC controller */
        COMPAT_INTEL_BAYTRAIL_FSP,      /* Intel Bay Trail FSP */
        COMPAT_INTEL_BAYTRAIL_FSP_MDP,  /* Intel FSP memory-down params */

        COMPAT_COUNT,
};

#define MAX_PHANDLE_ARGS 16
struct fdtdec_phandle_args {
        int node;
        int args_count;
        uint32_t args[MAX_PHANDLE_ARGS];
};

/**
 * fdtdec_parse_phandle_with_args() - Find a node pointed by phandle in a list
 *
 * This function is useful to parse lists of phandles and their arguments.
 *
 * Example:
 *
 * phandle1: node1 {
 *      #list-cells = <2>;
 * }
 *
 * phandle2: node2 {
 *      #list-cells = <1>;
 * }
 *
 * node3 {
 *      list = <&phandle1 1 2 &phandle2 3>;
 * }
 *
 * To get a device_node of the `node2' node you may call this:
 * fdtdec_parse_phandle_with_args(blob, node3, "list", "#list-cells", 0, 1,
 *                                &args);
 *
 * (This function is a modified version of __of_parse_phandle_with_args() from
 * Linux 3.18)
 *
 * @blob:       Pointer to device tree
 * @src_node:   Offset of device tree node containing a list
 * @list_name:  property name that contains a list
 * @cells_name: property name that specifies the phandles' arguments count,
 *              or NULL to use @cells_count
 * @cells_count: Cell count to use if @cells_name is NULL
 * @index:      index of a phandle to parse out
 * @out_args:   optional pointer to output arguments structure (will be filled)
 * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
 *      @list_name does not exist, a phandle was not found, @cells_name
 *      could not be found, the arguments were truncated or there were too
 *      many arguments.
 *
 */
int fdtdec_parse_phandle_with_args(const void *blob, int src_node,
                                   const char *list_name,
                                   const char *cells_name,
                                   int cell_count, int index,
                                   struct fdtdec_phandle_args *out_args);

/**
 * 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 the parsed address, and
 * optionally the parsed size.
 *
 * This variant assumes a known and fixed number of cells are used to
 * represent the address and size.
 *
 * You probably don't want to use this function directly except to parse
 * non-standard properties, and never to parse the "reg" property. Instead,
 * use one of the "auto" variants below, which automatically honor the
 * #address-cells and #size-cells properties in the parent node.
 *
 * @param blob  FDT blob
 * @param node  node to examine
 * @param prop_name     name of property to find
 * @param index which address to retrieve from a list of addresses. Often 0.
 * @param na    the number of cells used to represent an address
 * @param ns    the number of cells used to represent a size
 * @param sizep a pointer to store the size into. Use NULL if not required
 * @return address, if found, or FDT_ADDR_T_NONE if not
 */
fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
                const char *prop_name, int index, int na, int ns,
                fdt_size_t *sizep);

/*
 * Look up an address property in a node and return the parsed address, and
 * optionally the parsed size.
 *
 * This variant automatically determines the number of cells used to represent
 * the address and size by parsing the provided parent node's #address-cells
 * and #size-cells properties.
 *
 * @param blob  FDT blob
 * @param parent        parent node of @node
 * @param node  node to examine
 * @param prop_name     name of property to find
 * @param index which address to retrieve from a list of addresses. Often 0.
 * @param sizep a pointer to store the size into. Use NULL if not required
 * @return address, if found, or FDT_ADDR_T_NONE if not
 */
fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
                int node, const char *prop_name, int index, fdt_size_t *sizep);

/*
 * Look up an address property in a node and return the parsed address, and
 * optionally the parsed size.
 *
 * This variant automatically determines the number of cells used to represent
 * the address and size by parsing the parent node's #address-cells
 * and #size-cells properties. The parent node is automatically found.
 *
 * The automatic parent lookup implemented by this function is slow.
 * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
 * possible.
 *
 * @param blob  FDT blob
 * @param parent        parent node of @node
 * @param node  node to examine
 * @param prop_name     name of property to find
 * @param index which address to retrieve from a list of addresses. Often 0.
 * @param sizep a pointer to store the size into. Use NULL if not required
 * @return address, if found, or FDT_ADDR_T_NONE if not
 */
fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
                const char *prop_name, int index, fdt_size_t *sizep);

/*
 * Look up an address property in a node and return the parsed address.
 *
 * This variant hard-codes the number of cells used to represent the address
 * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
 * always returns the first address value in the property (index 0).
 *
 * Use of this function is not recommended due to the hard-coding of cell
 * counts. There is no programmatic validation that these hard-coded values
 * actually match the device tree content in any way at all. This assumption
 * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
 * set in the U-Boot build and exercising strict control over DT content to
 * ensure use of matching #address-cells/#size-cells properties. However, this
 * approach is error-prone; those familiar with DT will not expect the
 * assumption to exist, and could easily invalidate it. If the assumption is
 * invalidated, this function will not report the issue, and debugging will
 * be required. Instead, use fdtdec_get_addr_size_auto_parent().
 *
 * @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 an address property in a node and return the parsed address, and
 * optionally the parsed size.
 *
 * This variant hard-codes the number of cells used to represent the address
 * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
 * always returns the first address value in the property (index 0).
 *
 * Use of this function is not recommended due to the hard-coding of cell
 * counts. There is no programmatic validation that these hard-coded values
 * actually match the device tree content in any way at all. This assumption
 * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
 * set in the U-Boot build and exercising strict control over DT content to
 * ensure use of matching #address-cells/#size-cells properties. However, this
 * approach is error-prone; those familiar with DT will not expect the
 * assumption to exist, and could easily invalidate it. If the assumption is
 * invalidated, this function will not report the issue, and debugging will
 * be required. Instead, use fdtdec_get_addr_size_auto_parent().
 *
 * @param blob  FDT blob
 * @param node  node to examine
 * @param prop_name     name of property to find
 * @param sizep a pointer to store the size into. Use NULL if not required
 * @return address, if found, or FDT_ADDR_T_NONE if not
 */
fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
                const char *prop_name, fdt_size_t *sizep);

/**
 * Look at an address property in a node and return the pci address which
 * corresponds to the given type in the form of fdt_pci_addr.
 * The property must hold one fdt_pci_addr with a lengh.
 *
 * @param blob          FDT blob
 * @param node          node to examine
 * @param type          pci address type (FDT_PCI_SPACE_xxx)
 * @param prop_name     name of property to find
 * @param addr          returns pci address in the form of fdt_pci_addr
 * @return 0 if ok, -ENOENT if the property did not exist, -EINVAL if the
 *              format of the property was invalid, -ENXIO if the requested
 *              address type was not found
 */
int fdtdec_get_pci_addr(const void *blob, int node, enum fdt_pci_space type,
                const char *prop_name, struct fdt_pci_addr *addr);

/**
 * Look at the compatible property of a device node that represents a PCI
 * device and extract pci vendor id and device id from it.
 *
 * @param blob          FDT blob
 * @param node          node to examine
 * @param vendor        vendor id of the pci device
 * @param device        device id of the pci device
 * @return 0 if ok, negative on error
 */
int fdtdec_get_pci_vendev(const void *blob, int node,
                u16 *vendor, u16 *device);

/**
 * Look at the pci address of a device node that represents a PCI device
 * and parse the bus, device and function number from it. For some cases
 * like the bus number encoded in reg property is not correct after pci
 * enumeration, this function looks through the node's compatible strings
 * to get these numbers extracted instead.
 *
 * @param blob          FDT blob
 * @param node          node to examine
 * @param addr          pci address in the form of fdt_pci_addr
 * @param bdf           returns bus, device, function triplet
 * @return 0 if ok, negative on error
 */
int fdtdec_get_pci_bdf(const void *blob, int node,
                struct fdt_pci_addr *addr, pci_dev_t *bdf);

/**
 * Look at the pci address of a device node that represents a PCI device
 * and return base address of the pci device's registers.
 *
 * @param blob          FDT blob
 * @param node          node to examine
 * @param addr          pci address in the form of fdt_pci_addr
 * @param bar           returns base address of the pci device's registers
 * @return 0 if ok, negative on error
 */
int fdtdec_get_pci_bar32(const void *blob, int node,
                struct fdt_pci_addr *addr, u32 *bar);

/**
 * 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);

/**
 * Get a variable-sized number from a property
 *
 * This reads a number from one or more cells.
 *
 * @param ptr   Pointer to property
 * @param cells Number of cells containing the number
 * @return the value in the cells
 */
u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells);

/**
 * 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 alias sequence number of a node
 *
 * This works out whether a node is pointed to by an alias, and if so, the
 * sequence number of that alias. Aliases are of the form <base><num> where
 * <num> is the sequence number. For example spi2 would be sequence number
 * 2.
 *
 * @param blob          Device tree blob (if NULL, then error is returned)
 * @param base          Base name for alias (before the underscore)
 * @param node          Node to look up
 * @param seqp          This is set to the sequence number if one is found,
 *                      but otherwise the value is left alone
 * @return 0 if a sequence was found, -ve if not
 */
int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
                         int *seqp);

/**
 * Get the offset of the given chosen node
 *
 * This looks up a property in /chosen containing the path to another node,
 * then finds the offset of that node.
 *
 * @param blob          Device tree blob (if NULL, then error is returned)
 * @param name          Property name, e.g. "stdout-path"
 * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
 */
int fdtdec_get_chosen_node(const void *blob, const char *name);

/*
 * 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 its contents in an integer
 * array of given length. The property must exist but may have less data that
 * expected (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 number of array elements if ok, or -FDT_ERR_NOTFOUND if the
 *              property is not found
 */
int fdtdec_get_int_array_count(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);

/**
 * 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 basep         Returns base address of region
 * @param size          Returns size of region
 * @return 0 if ok, -1 on error (property not found)
 */
int fdtdec_decode_region(const void *blob, int node, const char *prop_name,
                         fdt_addr_t *basep, fdt_size_t *sizep);

enum fmap_compress_t {
        FMAP_COMPRESS_NONE,
        FMAP_COMPRESS_LZO,
};

enum fmap_hash_t {
        FMAP_HASH_NONE,
        FMAP_HASH_SHA1,
        FMAP_HASH_SHA256,
};

/* A flash map entry, containing an offset and length */
struct fmap_entry {
        uint32_t offset;
        uint32_t length;
        uint32_t used;                  /* Number of bytes used in region */
        enum fmap_compress_t compress_algo;     /* Compression type */
        enum fmap_hash_t hash_algo;             /* Hash algorithm */
        const uint8_t *hash;                    /* Hash value */
        int hash_size;                          /* Hash size */
};

/**
 * Read a flash entry from the fdt
 *
 * @param blob          FDT blob
 * @param node          Offset of node to read
 * @param name          Name of node being read
 * @param entry         Place to put offset and size of this node
 * @return 0 if ok, -ve on error
 */
int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
                           struct fmap_entry *entry);

/**
 * Obtain an indexed resource from a device property.
 *
 * @param fdt           FDT blob
 * @param node          node to examine
 * @param property      name of the property to parse
 * @param index         index of the resource to retrieve
 * @param res           returns the resource
 * @return 0 if ok, negative on error
 */
int fdt_get_resource(const void *fdt, int node, const char *property,
                     unsigned int index, struct fdt_resource *res);

/**
 * Obtain a named resource from a device property.
 *
 * Look up the index of the name in a list of strings and return the resource
 * at that index.
 *
 * @param fdt           FDT blob
 * @param node          node to examine
 * @param property      name of the property to parse
 * @param prop_names    name of the property containing the list of names
 * @param name          the name of the entry to look up
 * @param res           returns the resource
 */
int fdt_get_named_resource(const void *fdt, int node, const char *property,
                           const char *prop_names, const char *name,
                           struct fdt_resource *res);

/**
 * Decode a named region within a memory bank of a given type.
 *
 * This function handles selection of a memory region. The region is
 * specified as an offset/size within a particular type of memory.
 *
 * The properties used are:
 *
 *      <mem_type>-memory<suffix> for the name of the memory bank
 *      <mem_type>-offset<suffix> for the offset in that bank
 *
 * The property value must have an offset and a size. The function checks
 * that the region is entirely within the memory bank.5
 *
 * @param blob          FDT blob
 * @param node          Node containing the properties (-1 for /config)
 * @param mem_type      Type of memory to use, which is a name, such as
 *                      "u-boot" or "kernel".
 * @param suffix        String to append to the memory/offset
 *                      property names
 * @param basep         Returns base of region
 * @param sizep         Returns size of region
 * @return 0 if OK, -ive on error
 */
int fdtdec_decode_memory_region(const void *blob, int node,
                                const char *mem_type, const char *suffix,
                                fdt_addr_t *basep, fdt_size_t *sizep);

/* Display timings from linux include/video/display_timing.h */
enum display_flags {
        DISPLAY_FLAGS_HSYNC_LOW         = 1 << 0,
        DISPLAY_FLAGS_HSYNC_HIGH        = 1 << 1,
        DISPLAY_FLAGS_VSYNC_LOW         = 1 << 2,
        DISPLAY_FLAGS_VSYNC_HIGH        = 1 << 3,

        /* data enable flag */
        DISPLAY_FLAGS_DE_LOW            = 1 << 4,
        DISPLAY_FLAGS_DE_HIGH           = 1 << 5,
        /* drive data on pos. edge */
        DISPLAY_FLAGS_PIXDATA_POSEDGE   = 1 << 6,
        /* drive data on neg. edge */
        DISPLAY_FLAGS_PIXDATA_NEGEDGE   = 1 << 7,
        DISPLAY_FLAGS_INTERLACED        = 1 << 8,
        DISPLAY_FLAGS_DOUBLESCAN        = 1 << 9,
        DISPLAY_FLAGS_DOUBLECLK         = 1 << 10,
};

/*
 * A single signal can be specified via a range of minimal and maximal values
 * with a typical value, that lies somewhere inbetween.
 */
struct timing_entry {
        u32 min;
        u32 typ;
        u32 max;
};

/*
 * Single "mode" entry. This describes one set of signal timings a display can
 * have in one setting. This struct can later be converted to struct videomode
 * (see include/video/videomode.h). As each timing_entry can be defined as a
 * range, one struct display_timing may become multiple struct videomodes.
 *
 * Example: hsync active high, vsync active low
 *
 *                                  Active Video
 * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
 *        |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
 *        |          |   porch  |                    |   porch   |
 *
 * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
 *
 * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
 */
struct display_timing {
        struct timing_entry pixelclock;

        struct timing_entry hactive;            /* hor. active video */
        struct timing_entry hfront_porch;       /* hor. front porch */
        struct timing_entry hback_porch;        /* hor. back porch */
        struct timing_entry hsync_len;          /* hor. sync len */

        struct timing_entry vactive;            /* ver. active video */
        struct timing_entry vfront_porch;       /* ver. front porch */
        struct timing_entry vback_porch;        /* ver. back porch */
        struct timing_entry vsync_len;          /* ver. sync len */

        enum display_flags flags;               /* display flags */
};

/**
 * fdtdec_decode_display_timing() - decode display timings
 *
 * Decode display timings from the supplied 'display-timings' node.
 * See doc/device-tree-bindings/video/display-timing.txt for binding
 * information.
 *
 * @param blob          FDT blob
 * @param node          'display-timing' node containing the timing subnodes
 * @param index         Index number to read (0=first timing subnode)
 * @param config        Place to put timings
 * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
 */
int fdtdec_decode_display_timing(const void *blob, int node, int index,
                                 struct display_timing *config);
/**
 * Set up the device tree ready for use
 */
int fdtdec_setup(void);

#endif