Add missing init_targets documentation

Add init_targets procedure documentation to OpenOCD manual explaining
the concept.

Change-Id: I82933ed90397cbcdc5c72801182573ca69b1d265
Signed-off-by: Freddie Chopin <freddie.chopin@gmail.com>
Reviewed-on: http://openocd.zylin.com/439
Reviewed-by: Chris Morgan <chmorgan@gmail.com>
Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>
This commit is contained in:
Freddie Chopin 2012-02-09 17:50:42 +01:00 committed by Peter Stuge
parent f86986a9ef
commit 394dcc8e34
1 changed files with 40 additions and 0 deletions

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@ -1810,6 +1810,45 @@ OpenOCD verifies the scan chain after reset,
look at how you are setting up JTAG clocking.
@end quotation
@anchor{The init_targets procedure}
@subsection The init_targets procedure
@cindex init_targets procedure
Target config files can either be ``linear'' (script executed line-by-line when parsed in configuration stage,
@xref{Configuration Stage}) or they can contain a special procedure called @code{init_targets}, which will be executed
when entering run stage (after parsing all config files or after @code{init} command, @xref{Entering the Run Stage}).
Such procedure can be overriden by ``next level'' script (which sources the original). This concept faciliates code
reuse when basic target config files provide generic configuration procedures and @code{init_targets} procedure, which
can then be sourced and enchanced or changed in a ``more specific'' target config file. This is not possible with
``linear'' config scripts, because sourcing them executes every initialization commands they provide.
@example
### generic_file.cfg ###
proc setup_my_chip @{chip_name flash_size ram_size@} @{
# basic initialization procedure ...
@}
proc init_targets @{@} @{
# initializes generic chip with 4kB of flash and 1kB of RAM
setup_my_chip MY_GENERIC_CHIP 4096 1024
@}
### specific_file.cfg ###
source [find target/generic_file.cfg]
proc init_targets @{@} @{
# initializes specific chip with 128kB of flash and 64kB of RAM
setup_my_chip MY_CHIP_WITH_128K_FLASH_64KB_RAM 131072 65536
@}
@end example
The easiest way to convert ``linear'' config files to @code{init_targets} version is to enclose every line of ``code''
(i.e. not @code{source} commands, procedures, etc.) in this procedure.
For an example of this scheme see LPC2000 target config files.
@subsection ARM Core Specific Hacks
If the chip has a DCC, enable it. If the chip is an ARM9 with some
@ -1922,6 +1961,7 @@ may access or activate TAPs.
After it leaves this stage, configuration commands may no
longer be issued.
@anchor{Entering the Run Stage}
@section Entering the Run Stage
The first thing OpenOCD does after leaving the configuration