include/linux/of_fdt.h

/*
 * Definitions for working with the Flattened Device Tree data format
 *
 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
 * benh@kernel.crashing.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#ifndef _LINUX_OF_FDT_H
#define _LINUX_OF_FDT_H

#include <linux/types.h>
#include <linux/init.h>

/* Definitions used by the flattened device tree */
#define OF_DT_HEADER		0xd00dfeed	/* marker */
#define OF_DT_BEGIN_NODE	0x1		/* Start of node, full name */
#define OF_DT_END_NODE		0x2		/* End node */
#define OF_DT_PROP		0x3		/* Property: name off, size,
						 * content */
#define OF_DT_NOP		0x4		/* nop */
#define OF_DT_END		0x9

#define OF_DT_VERSION		0x10

#ifndef __ASSEMBLY__
/*
 * This is what gets passed to the kernel by prom_init or kexec
 *
 * The dt struct contains the device tree structure, full pathes and
 * property contents. The dt strings contain a separate block with just
 * the strings for the property names, and is fully page aligned and
 * self contained in a page, so that it can be kept around by the kernel,
 * each property name appears only once in this page (cheap compression)
 *
 * the mem_rsvmap contains a map of reserved ranges of physical memory,
 * passing it here instead of in the device-tree itself greatly simplifies
 * the job of everybody. It's just a list of u64 pairs (base/size) that
 * ends when size is 0
 */
struct boot_param_header {
	__be32	magic;			/* magic word OF_DT_HEADER */
	__be32	totalsize;		/* total size of DT block */
	__be32	off_dt_struct;		/* offset to structure */
	__be32	off_dt_strings;		/* offset to strings */
	__be32	off_mem_rsvmap;		/* offset to memory reserve map */
	__be32	version;		/* format version */
	__be32	last_comp_version;	/* last compatible version */
	/* version 2 fields below */
	__be32	boot_cpuid_phys;	/* Physical CPU id we're booting on */
	/* version 3 fields below */
	__be32	dt_strings_size;	/* size of the DT strings block */
	/* version 17 fields below */
	__be32	dt_struct_size;		/* size of the DT structure block */
};

#if defined(CONFIG_OF_FLATTREE)

struct device_node;

/* For scanning an arbitrary device-tree at any time */
extern char *of_fdt_get_string(struct boot_param_header *blob, u32 offset);
extern void *of_fdt_get_property(struct boot_param_header *blob,
				 unsigned long node,
				 const char *name,
				 unsigned long *size);
extern int of_fdt_is_compatible(struct boot_param_header *blob,
				unsigned long node,
				const char *compat);
extern int of_fdt_match(struct boot_param_header *blob, unsigned long node,
			const char *const *compat);
extern void of_fdt_unflatten_tree(unsigned long *blob,
			       struct device_node **mynodes);

/* TBD: Temporary export of fdt globals - remove when code fully merged */
extern int __initdata dt_root_addr_cells;
extern int __initdata dt_root_size_cells;
extern struct boot_param_header *initial_boot_params;

/* For scanning the flat device-tree at boot time */
extern char *find_flat_dt_string(u32 offset);
extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
				     int depth, void *data),
			   void *data);
extern void *of_get_flat_dt_prop(unsigned long node, const char *name,
				 unsigned long *size);
extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
extern int of_flat_dt_match(unsigned long node, const char *const *matches);
extern unsigned long of_get_flat_dt_root(void);

/*
 * early_init_dt_scan_chosen - scan the device tree for ramdisk and bootargs
 *
 * The boot arguments will be placed into the memory pointed to by @data.
 * That memory should be COMMAND_LINE_SIZE big and initialized to be a valid
 * (possibly empty) string.  Logic for what will be in @data after this
 * function finishes:
 *
 * - CONFIG_CMDLINE_FORCE=true
 *     CONFIG_CMDLINE
 * - CONFIG_CMDLINE_EXTEND=true, @data is non-empty string
 *     @data + dt bootargs (even if dt bootargs are empty)
 * - CONFIG_CMDLINE_EXTEND=true, @data is empty string
 *     CONFIG_CMDLINE + dt bootargs (even if dt bootargs are empty)
 * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=non-empty:
 *     dt bootargs
 * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is non-empty string
 *     @data is left unchanged
 * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is empty string
 *     CONFIG_CMDLINE (or "" if that's not defined)
 */
extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
				     int depth, void *data);
extern void early_init_dt_check_for_initrd(unsigned long node);
extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
				     int depth, void *data);
extern void early_init_dt_add_memory_arch(u64 base, u64 size);
extern void * early_init_dt_alloc_memory_arch(u64 size, u64 align);
extern u64 dt_mem_next_cell(int s, __be32 **cellp);

/*
 * If BLK_DEV_INITRD, the fdt early init code will call this function,
 * to be provided by the arch code. start and end are specified as
 * physical addresses.
 */
#ifdef CONFIG_BLK_DEV_INITRD
extern void early_init_dt_setup_initrd_arch(unsigned long start,
					    unsigned long end);
#endif

/* Early flat tree scan hooks */
extern int early_init_dt_scan_root(unsigned long node, const char *uname,
				   int depth, void *data);

/* Other Prototypes */
extern void unflatten_device_tree(void);
extern void early_init_devtree(void *);
#else /* CONFIG_OF_FLATTREE */
static inline void unflatten_device_tree(void) {}
#endif /* CONFIG_OF_FLATTREE */

#endif /* __ASSEMBLY__ */
#endif /* _LINUX_OF_FDT_H */