Commit 53c0fb6e authored by Michel Jaouen's avatar Michel Jaouen Committed by Øyvind Harboe
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cortex a : smp doc update

parent 289ceceb
......@@ -1679,6 +1679,64 @@ Again using the at91sam7 as an example, this can look like:
$_TARGETNAME configure -work-area-phys 0x00200000 \
-work-area-size 0x4000 -work-area-backup 0
@end example
@pxref{Define CPU targets working in SMP}
@anchor{Define CPU targets working in SMP}
@subsection Define CPU targets working in SMP
@cindex SMP
After setting targets, you can define a list of targets working in SMP.
target create $_TARGETNAME_1 cortex_a8 -chain-position $_CHIPNAME.dap \
-coreid 0 -dbgbase $_DAP_DBG1
target create $_TARGETNAME_2 cortex_a8 -chain-position $_CHIPNAME.dap \
-coreid 1 -dbgbase $_DAP_DBG2
#define 2 targets working in smp.
target smp $_CHIPNAME.cpu2 $_CHIPNAME.cpu1
@end example
In the above example on cortex_a8, 2 cpus are working in SMP.
In SMP only one GDB instance is created and :
@itemize @bullet
@item a set of hardware breakpoint sets the same breakpoint on all targets in the list.
@item halt command triggers the halt of all targets in the list.
@item resume command triggers the write context and the restart of all targets in the list.
@item following a breakpoint: the target stopped by the breakpoint is displayed to the GDB session.
@item dedicated GDB serial protocol packets are implemented for switching/retrieving the target
displayed by the GDB session @pxref{Using openocd SMP with GDB}.
@end itemize
The SMP behaviour can be disabled/enabled dynamically. On cortex_a8 following
command have been implemented.
@itemize @bullet
@item cortex_a8 smp_on : enable SMP mode, behaviour is as described above.
@item cortex_a8 smp_off : disable SMP mode, the current target is the one
displayed in the GDB session, only this target is now controlled by GDB
session. This behaviour is useful during system boot up.
@item cortex_a8 smp_gdb : display/fix the core id displayed in GDB session see
following example.
@end itemize
>cortex_a8 smp_gdb
gdb coreid 0 -> -1
#0 : coreid 0 is displayed to GDB ,
#-> -1 : next resume triggers a real resume
> cortex_a8 smp_gdb 1
gdb coreid 0 -> 1
#0 :coreid 0 is displayed to GDB ,
#->1 : next resume displays coreid 1 to GDB
> resume
> cortex_a8 smp_gdb
gdb coreid 1 -> 1
#1 :coreid 1 is displayed to GDB ,
#->1 : next resume displays coreid 1 to GDB
> cortex_a8 smp_gdb -1
gdb coreid 1 -> -1
#1 :coreid 1 is displayed to GDB,
#->-1 : next resume triggers a real resume
@end example
@subsection Chip Reset Setup
......@@ -7275,6 +7333,55 @@ $_TARGETNAME configure -event EVENTNAME BODY
To verify any flash programming the GDB command @option{compare-sections}
can be used.
@anchor{Using openocd SMP with GDB}
@section Using openocd SMP with GDB
@cindex SMP
For SMP support following GDB serial protocol packet have been defined :
@itemize @bullet
@item j - smp status request
@item J - smp set request
@end itemize
OpenOCD implements :
@itemize @bullet
@item @option{jc} packet for reading core id displayed by
GDB connection. Reply is @option{XXXXXXXX} (8 hex digits giving core id) or
@option{E01} for target not smp.
@item @option{JcXXXXXXXX} (8 hex digits) packet for setting core id displayed at next GDB continue
(core id -1 is reserved for returning to normal resume mode). Reply @option{E01}
for target not smp or @option{OK} on success.
@end itemize
Handling of this packet within GDB can be done :
@itemize @bullet
@item by the creation of an internal variable (i.e @option{_core}) by mean
of function allocate_computed_value allowing following GDB command.
set $_core 1
#Jc01 packet is sent
print $_core
#jc packet is sent and result is affected in $
@end example
@item by the usage of GDB maintenance command as described in following example (2
cpus in SMP with core id 0 and 1 @pxref{Define CPU targets working in SMP}).
# toggle0 : force display of coreid 0
define toggle0
maint packet Jc0
main packet Jc-1
# toggle1 : force display of coreid 1
define toggle1
maint packet Jc1
main packet Jc-1
@end example
@end itemize
@node Tcl Scripting API
@chapter Tcl Scripting API
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