u-boot/include/fdtdec.h

389 lines
14 KiB
C

/*
* 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)
#else
typedef u32 fdt_addr_t;
#define FDT_ADDR_T_NONE (-1U)
#define fdt_addr_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_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_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)
/**
* 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 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);
/**
* 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);
/**
* 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 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);
#endif