656d8da9d2
Commit ad7061ed74 ("doc: Move device tree bindings documentation to
doc/device-tree-bindings") moved all device tree binding documentation
to doc/device-tree-bindings directory.
The current U-Boot project still have two documentation directories:
- doc/
- Documentation/
Move all documentation and sphinx files to doc directory so all content
can be in a common place.
Signed-off-by: Breno Lima <breno.lima@nxp.com>
101 lines
3.0 KiB
ReStructuredText
101 lines
3.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
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Linker-Generated Arrays
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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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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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This ensures uniqueness for both input section and C variable name.
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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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Entry variables need never be referred to directly.
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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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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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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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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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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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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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.. kernel-doc:: include/linker_lists.h
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:internal:
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