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/omap3530.cfg

@@ -20,9 +20,9 @@ if { [info exists DAP_TAPID] } {
 } else {
    set _DAP_TAPID 0x0b6d602f
 }
-jtag newtap $_CHIPNAME dap -irlen 4 -ircapture 0x1 -irmask 0xf \
+jtag newtap $_CHIPNAME cpu -irlen 4 -ircapture 0x1 -irmask 0xf \
 	-expected-id $_DAP_TAPID -disable
-jtag configure $_CHIPNAME.dap -event tap-enable \
+jtag configure $_CHIPNAME.cpu -event tap-enable \
 	"icepick_c_tapenable $_CHIPNAME.jrc 3"
 
 # Primary TAP: ICEpick-C (JTAG route controller) and boundary scan
@@ -36,7 +36,8 @@ jtag newtap $_CHIPNAME jrc -irlen 6 -ircapture 0x1 -irmask 0x3f \
 
 # GDB target: Cortex-A8, using DAP
 set _TARGETNAME $_CHIPNAME.cpu
-target create $_TARGETNAME cortex_a -chain-position $_CHIPNAME.dap
+dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.cpu
+target create $_TARGETNAME cortex_a -dap $_CHIPNAME.dap
 
 # SRAM: 64K at 0x4020.0000; use the first 16K
 $_TARGETNAME configure -work-area-phys 0x40200000 -work-area-size 0x4000