83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
320 lines
11 KiB
C
320 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* include/linker_lists.h
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*
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* Implementation of linker-generated arrays
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*
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* Copyright (C) 2012 Marek Vasut <marex@denx.de>
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*/
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#ifndef __LINKER_LISTS_H__
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#define __LINKER_LISTS_H__
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#include <linux/compiler.h>
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/*
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* There is no use in including this from ASM files.
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* So just don't define anything when included from ASM.
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*/
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#if !defined(__ASSEMBLY__)
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/**
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* A linker list is constructed by grouping together linker input
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* sections, each containing one entry of the list. Each input section
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* contains a constant initialized variable which holds the entry's
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* content. Linker list input sections are constructed from the list
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* and entry names, plus a prefix which allows grouping all lists
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* together. Assuming _list and _entry are the list and entry names,
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* then the corresponding input section name is
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*
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* .u_boot_list_ + 2_ + @_list + _2_ + @_entry
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*
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* and the C variable name is
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*
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* _u_boot_list + _2_ + @_list + _2_ + @_entry
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*
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* This ensures uniqueness for both input section and C variable name.
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*
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* Note that the names differ only in the first character, "." for the
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* section and "_" for the variable, so that the linker cannot confuse
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* section and symbol names. From now on, both names will be referred
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* to as
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*
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* %u_boot_list_ + 2_ + @_list + _2_ + @_entry
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*
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* Entry variables need never be referred to directly.
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*
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* The naming scheme for input sections allows grouping all linker lists
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* into a single linker output section and grouping all entries for a
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* single list.
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*
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* Note the two '_2_' constant components in the names: their presence
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* allows putting a start and end symbols around a list, by mapping
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* these symbols to sections names with components "1" (before) and
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* "3" (after) instead of "2" (within).
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* Start and end symbols for a list can generally be defined as
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*
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* %u_boot_list_2_ + @_list + _1_...
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* %u_boot_list_2_ + @_list + _3_...
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*
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* Start and end symbols for the whole of the linker lists area can be
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* defined as
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*
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* %u_boot_list_1_...
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* %u_boot_list_3_...
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*
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* Here is an example of the sorted sections which result from a list
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* "array" made up of three entries : "first", "second" and "third",
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* iterated at least once.
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*
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* .u_boot_list_2_array_1
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* .u_boot_list_2_array_2_first
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* .u_boot_list_2_array_2_second
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* .u_boot_list_2_array_2_third
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* .u_boot_list_2_array_3
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*
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* If lists must be divided into sublists (e.g. for iterating only on
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* part of a list), one can simply give the list a name of the form
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* 'outer_2_inner', where 'outer' is the global list name and 'inner'
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* is the sub-list name. Iterators for the whole list should use the
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* global list name ("outer"); iterators for only a sub-list should use
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* the full sub-list name ("outer_2_inner").
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*
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* Here is an example of the sections generated from a global list
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* named "drivers", two sub-lists named "i2c" and "pci", and iterators
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* defined for the whole list and each sub-list:
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*
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* %u_boot_list_2_drivers_1
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* %u_boot_list_2_drivers_2_i2c_1
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* %u_boot_list_2_drivers_2_i2c_2_first
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* %u_boot_list_2_drivers_2_i2c_2_first
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* %u_boot_list_2_drivers_2_i2c_2_second
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* %u_boot_list_2_drivers_2_i2c_2_third
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* %u_boot_list_2_drivers_2_i2c_3
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* %u_boot_list_2_drivers_2_pci_1
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* %u_boot_list_2_drivers_2_pci_2_first
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* %u_boot_list_2_drivers_2_pci_2_second
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* %u_boot_list_2_drivers_2_pci_2_third
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* %u_boot_list_2_drivers_2_pci_3
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* %u_boot_list_2_drivers_3
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*/
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/**
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* llsym() - Access a linker-generated array entry
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* @_type: Data type of the entry
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* @_name: Name of the entry
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* @_list: name of the list. Should contain only characters allowed
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* in a C variable name!
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*/
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#define llsym(_type, _name, _list) \
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((_type *)&_u_boot_list_2_##_list##_2_##_name)
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/**
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* ll_entry_declare() - Declare linker-generated array entry
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* @_type: Data type of the entry
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* @_name: Name of the entry
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* @_list: name of the list. Should contain only characters allowed
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* in a C variable name!
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*
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* This macro declares a variable that is placed into a linker-generated
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* array. This is a basic building block for more advanced use of linker-
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* generated arrays. The user is expected to build their own macro wrapper
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* around this one.
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*
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* A variable declared using this macro must be compile-time initialized.
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*
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* Special precaution must be made when using this macro:
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*
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* 1) The _type must not contain the "static" keyword, otherwise the
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* entry is generated and can be iterated but is listed in the map
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* file and cannot be retrieved by name.
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*
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* 2) In case a section is declared that contains some array elements AND
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* a subsection of this section is declared and contains some elements,
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* it is imperative that the elements are of the same type.
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*
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* 4) In case an outer section is declared that contains some array elements
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* AND an inner subsection of this section is declared and contains some
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* elements, then when traversing the outer section, even the elements of
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* the inner sections are present in the array.
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*
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* Example:
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* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub) = {
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* .x = 3,
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* .y = 4,
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* };
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*/
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#define ll_entry_declare(_type, _name, _list) \
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_type _u_boot_list_2_##_list##_2_##_name __aligned(4) \
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__attribute__((unused, \
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section(".u_boot_list_2_"#_list"_2_"#_name)))
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/**
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* ll_entry_declare_list() - Declare a list of link-generated array entries
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* @_type: Data type of each entry
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* @_name: Name of the entry
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* @_list: name of the list. Should contain only characters allowed
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* in a C variable name!
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*
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* This is like ll_entry_declare() but creates multiple entries. It should
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* be assigned to an array.
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*
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* ll_entry_declare_list(struct my_sub_cmd, my_sub_cmd, cmd_sub) = {
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* { .x = 3, .y = 4 },
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* { .x = 8, .y = 2 },
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* { .x = 1, .y = 7 }
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* };
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*/
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#define ll_entry_declare_list(_type, _name, _list) \
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_type _u_boot_list_2_##_list##_2_##_name[] __aligned(4) \
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__attribute__((unused, \
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section(".u_boot_list_2_"#_list"_2_"#_name)))
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/**
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* We need a 0-byte-size type for iterator symbols, and the compiler
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* does not allow defining objects of C type 'void'. Using an empty
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* struct is allowed by the compiler, but causes gcc versions 4.4 and
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* below to complain about aliasing. Therefore we use the next best
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* thing: zero-sized arrays, which are both 0-byte-size and exempt from
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* aliasing warnings.
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*/
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/**
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* ll_entry_start() - Point to first entry of linker-generated array
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* @_type: Data type of the entry
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* @_list: Name of the list in which this entry is placed
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*
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* This function returns (_type *) pointer to the very first entry of a
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* linker-generated array placed into subsection of .u_boot_list section
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* specified by _list argument.
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*
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* Since this macro defines an array start symbol, its leftmost index
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* must be 2 and its rightmost index must be 1.
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*
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* Example:
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* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
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*/
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#define ll_entry_start(_type, _list) \
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({ \
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static char start[0] __aligned(4) __attribute__((unused, \
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section(".u_boot_list_2_"#_list"_1"))); \
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(_type *)&start; \
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})
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/**
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* ll_entry_end() - Point after last entry of linker-generated array
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* @_type: Data type of the entry
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* @_list: Name of the list in which this entry is placed
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* (with underscores instead of dots)
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*
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* This function returns (_type *) pointer after the very last entry of
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* a linker-generated array placed into subsection of .u_boot_list
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* section specified by _list argument.
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*
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* Since this macro defines an array end symbol, its leftmost index
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* must be 2 and its rightmost index must be 3.
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*
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* Example:
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* struct my_sub_cmd *msc = ll_entry_end(struct my_sub_cmd, cmd_sub);
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*/
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#define ll_entry_end(_type, _list) \
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({ \
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static char end[0] __aligned(4) __attribute__((unused, \
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section(".u_boot_list_2_"#_list"_3"))); \
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(_type *)&end; \
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})
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/**
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* ll_entry_count() - Return the number of elements in linker-generated array
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* @_type: Data type of the entry
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* @_list: Name of the list of which the number of elements is computed
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*
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* This function returns the number of elements of a linker-generated array
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* placed into subsection of .u_boot_list section specified by _list
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* argument. The result is of an unsigned int type.
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*
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* Example:
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* int i;
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* const unsigned int count = ll_entry_count(struct my_sub_cmd, cmd_sub);
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* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
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* for (i = 0; i < count; i++, msc++)
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* printf("Entry %i, x=%i y=%i\n", i, msc->x, msc->y);
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*/
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#define ll_entry_count(_type, _list) \
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({ \
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_type *start = ll_entry_start(_type, _list); \
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_type *end = ll_entry_end(_type, _list); \
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unsigned int _ll_result = end - start; \
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_ll_result; \
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})
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/**
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* ll_entry_get() - Retrieve entry from linker-generated array by name
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* @_type: Data type of the entry
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* @_name: Name of the entry
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* @_list: Name of the list in which this entry is placed
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*
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* This function returns a pointer to a particular entry in linker-generated
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* array identified by the subsection of u_boot_list where the entry resides
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* and it's name.
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*
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* Example:
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* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub) = {
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* .x = 3,
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* .y = 4,
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* };
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* ...
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* struct my_sub_cmd *c = ll_entry_get(struct my_sub_cmd, my_sub_cmd, cmd_sub);
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*/
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#define ll_entry_get(_type, _name, _list) \
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({ \
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extern _type _u_boot_list_2_##_list##_2_##_name; \
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_type *_ll_result = \
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&_u_boot_list_2_##_list##_2_##_name; \
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_ll_result; \
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})
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/**
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* ll_start() - Point to first entry of first linker-generated array
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* @_type: Data type of the entry
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*
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* This function returns (_type *) pointer to the very first entry of
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* the very first linker-generated array.
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*
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* Since this macro defines the start of the linker-generated arrays,
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* its leftmost index must be 1.
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*
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* Example:
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* struct my_sub_cmd *msc = ll_start(struct my_sub_cmd);
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*/
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#define ll_start(_type) \
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({ \
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static char start[0] __aligned(4) __attribute__((unused, \
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section(".u_boot_list_1"))); \
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(_type *)&start; \
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})
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/**
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* ll_end() - Point after last entry of last linker-generated array
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* @_type: Data type of the entry
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*
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* This function returns (_type *) pointer after the very last entry of
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* the very last linker-generated array.
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*
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* Since this macro defines the end of the linker-generated arrays,
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* its leftmost index must be 3.
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*
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* Example:
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* struct my_sub_cmd *msc = ll_end(struct my_sub_cmd);
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*/
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#define ll_end(_type) \
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({ \
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static char end[0] __aligned(4) __attribute__((unused, \
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section(".u_boot_list_3"))); \
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(_type *)&end; \
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})
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#endif /* __ASSEMBLY__ */
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#endif /* __LINKER_LISTS_H__ */
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