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/*
* include/linker_lists.h
*
* Implementation of linker-generated arrays
*
* Copyright (C) 2012 Marek Vasut <marex@denx.de>
*
* 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.
*/
#ifndef __LINKER_LISTS_H__
#define __LINKER_LISTS_H__
/**
* ll_entry_declare() - Declare linker-generated array entry
* @_type: Data type of the entry
* @_name: Name of the entry
* @_section_u: Subsection of u_boot_list in which this entry is placed
* (with underscores instead of dots, for name concatenation)
* @_section_d: Subsection of u_boot_list in which this entry is placed
* (with dots, for section concatenation)
*
* This macro declares a variable that is placed into a linker-generated
* array. This is a basic building block for more advanced use of linker-
* generated arrays. The user is expected to build their own macro wrapper
* around this one.
*
* A variable declared using this macro must be compile-time initialized
* and is as such placed into subsection of special section, .u_boot_list.
* The subsection is specified by the _section_[u,d] parameter, see below.
* The base name of the variable is _name, yet the actual variable is
* declared as concatenation of
*
* %_u_boot_list_ + @_section_u + _ + @_name
*
* which ensures name uniqueness. This variable shall never be refered
* directly though.
*
* Special precaution must be made when using this macro:
* 1) The _type must not contain the "static" keyword, otherwise the entry
* is not generated.
*
* 2) The @_section_u and @_section_d variables must match, the only difference
* is that in @_section_u is every dot "." character present in @_section_d
* replaced by a single underscore "_" character in @_section_u. The actual
* purpose of these parameters is to select proper subsection in the global
* .u_boot_list section.
*
* 3) In case a section is declared that contains some array elements AND a
* subsection of this section is declared and contains some elements, it is
* imperative that the elements are of the same type.
*
* 4) In case an outer section is declared that contains some array elements
* AND am inner subsection of this section is declared and contains some
* elements, then when traversing the outer section, even the elements of
* the inner sections are present in the array.
*
* Example:
* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub, cmd.sub) = {
* .x = 3,
* .y = 4,
* };
*/
#define ll_entry_declare(_type, _name, _section_u, _section_d) \
_type _u_boot_list_##_section_u##_##_name __attribute__(( \
unused, aligned(4), \
section(".u_boot_list."#_section_d"."#_name)))
/**
* ll_entry_start() - Point to first entry of linker-generated array
* @_type: Data type of the entry
* @_section_u: Subsection of u_boot_list in which this entry is placed
* (with underscores instead of dots)
*
* This function returns (_type *) pointer to the very first entry of a
* linker-generated array placed into subsection of .u_boot_list section
* specified by _section_u argument.
*
* Example:
* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
*/
#define ll_entry_start(_type, _section_u) \
({ \
extern _type _u_boot_list_##_section_u##__start; \
_type *_ll_result = &_u_boot_list_##_section_u##__start;\
_ll_result; \
})
/**
* ll_entry_count() - Return the number of elements in linker-generated array
* @_type: Data type of the entry
* @_section_u: Subsection of u_boot_list in which this entry is placed
* (with underscores instead of dots)
*
* This function returns the number of elements of a linker-generated array
* placed into subsection of .u_boot_list section specified by _section_u
* argument. The result is of an unsigned int type.
*
* Example:
* int i;
* const unsigned int count = ll_entry_count(struct my_sub_cmd, cmd_sub);
* struct my_sub_cmd *msc = ll_entry_start(struct my_sub_cmd, cmd_sub);
* for (i = 0; i < count; i++, msc++)
* printf("Entry %i, x=%i y=%i\n", i, msc->x, msc->y);
*/
#define ll_entry_count(_type, _section_u) \
({ \
extern _type _u_boot_list_##_section_u##__start; \
extern _type _u_boot_list_##_section_u##__end; \
unsigned int _ll_result = \
&_u_boot_list_##_section_u##__end - \
&_u_boot_list_##_section_u##__start; \
_ll_result; \
})
/**
* ll_entry_get() - Retrieve entry from linker-generated array by name
* @_type: Data type of the entry
* @_name: Name of the entry
* @_section_u: Subsection of u_boot_list in which this entry is placed
* (with underscores instead of dots)
*
* This function returns a pointer to a particular entry in LG-array
* identified by the subsection of u_boot_list where the entry resides
* and it's name.
*
* Example:
* ll_entry_declare(struct my_sub_cmd, my_sub_cmd, cmd_sub, cmd.sub) = {
* .x = 3,
* .y = 4,
* };
* ...
* struct my_sub_cmd *c = ll_entry_get(struct my_sub_cmd, my_sub_cmd, cmd_sub);
*/
#define ll_entry_get(_type, _name, _section_u) \
({ \
extern _type _u_boot_list_##_section_u##_##_name; \
_type *_ll_result = &_u_boot_list_##_section_u##_##_name;\
_ll_result; \
})
#endif /* __LINKER_LISTS_H__ */
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