target: restructure dap support

- add 'dap create' command to create dap instances
- move all dap subcmmand into the dap instance commands
- keep 'dap info' for convenience
- change all armv7 and armv8 targets to take a dap
  instance instead of a jtag chain position
- restructure tap/dap/target relations, jtag tap no
  longer references the dap, daps are now independently
  created and initialized.
- clean up swd connect
- re-initialize DAP also on JTAG errors (e.g. after reset,
  power cycle)
- update documentation
- update target files

Change-Id: I322cf3969b5407c25d1d3962f9d9b9bc1df067d9
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/4468
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

tcl/target/hi3798.cfg

@@ -16,8 +16,8 @@ if { [info exists DAP_TAPID] } {
 }
 
 # declare the one JTAG tap to access the DAP
-jtag newtap $_CHIPNAME dap -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_DAP_TAPID -ignore-version -enable
-
+jtag newtap $_CHIPNAME cpu -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_DAP_TAPID -ignore-version -enable
+dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.cpu
 # declare the 4 main application cores
 set _TARGETNAME $_CHIPNAME.cpu
 set _smp_command ""
@@ -33,7 +33,7 @@ for { set _core 0 } { $_core < $_cores } { incr _core 1 } {
     cti create cti$_core -dap $_CHIPNAME.dap -ctibase [set $_TARGETNAME.cti($_core)] -ap-num 0
 
     set _command "target create ${_TARGETNAME}$_core aarch64 \
-                         -chain-position $_CHIPNAME.dap -coreid $_core -ctibase [set $_TARGETNAME.cti($_core)]"
+                         -dap $_CHIPNAME.dap -coreid $_core -cti cti$_core"
 
     if { $_core != 0 } {
         # non-boot core examination may fail