Tweak TCL reset script ... mostly improving descriptions of

the various steps, but also calling [target names] only once.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2726 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/helper/startup.tcl b/src/helper/startup.tcl
index 3eb7419ffc6eb676da884aac9c2f27613db25d92..8c3ece56af6e938cf2795bd0c8c468bdeec50aa2 100644 (file)
--- a/src/helper/startup.tcl
+++ b/src/helper/startup.tcl
@@ -157,6 +157,7 @@ proc ocd_process_reset { MODE } {
 }
 
 proc ocd_process_reset_inner { MODE } {
+       set targets [target names]
 
        # If this target must be halted...
        set halt -1
@@ -175,26 +176,38 @@ proc ocd_process_reset_inner { MODE } {
 
        # Target event handlers *might* change which TAPs are enabled
        # or disabled, so we fire all of them.  But don't issue any
-       # of the "arp_*" commands, which may issue JTAG transactions,
+       # target "arp_*" commands, which may issue JTAG transactions,
        # unless we know the underlying TAP is active.
+       #
+       # NOTE:  ARP == "Advanced Reset Process" ... "advanced" is
+       # relative to a previous restrictive scheme
 
-       foreach t [ target names ] {
+       foreach t $targets {
                # New event script.
                $t invoke-event reset-start
        }
 
-       # Init the tap controller.
+       # Use TRST or TMS/TCK operations to reset all the tap controllers.
+       # TAP reset events get reported; they might enable some taps.
+       #
+       # REVISIT arp_init-reset pulses SRST (if it can) with TRST active;
+       # but SRST events aren't reported (unlike "jtag arp_reset", below)
        jtag arp_init-reset
 
        # Examine all targets on enabled taps.
-       foreach t [ target names ] {
+       foreach t $targets {
                if {[jtag tapisenabled [$t cget -chain-position]]} {
                        $t arp_examine
                }
        }
 
-       # Let the C code know we are asserting reset.
-       foreach t [ target names ] {
+       # Assert SRST, and report the pre/post events.
+       #
+       # REVISIT this presumes a single-target config, since SRST
+       # applies to the whole device-under-test.  When two targets
+       # both need special setup before SRST, it's only done for
+       # the first one...
+       foreach t $targets {
                $t invoke-event reset-assert-pre
                # C code needs to know if we expect to 'halt'
                if {[jtag tapisenabled [$t cget -chain-position]]} {
@@ -203,8 +216,8 @@ proc ocd_process_reset_inner { MODE } {
                $t invoke-event reset-assert-post
        }
 
-       # Now de-assert reset.
-       foreach t [ target names ] {
+       # Now de-assert SRST, and report the pre/post events.
+       foreach t $targets {
                $t invoke-event reset-deassert-pre
                # Again, de-assert code needs to know..
                if {[jtag tapisenabled [$t cget -chain-position]]} {
@@ -213,9 +226,11 @@ proc ocd_process_reset_inner { MODE } {
                $t invoke-event reset-deassert-post
        }
 
-       # Pass 1 - Now try to halt.
+       # Pass 1 - Now wait for any halt (requested as part of reset
+       # assert/deassert) to happen.  Ideally it takes effect without
+       # first executing any instructions.
        if { $halt } {
-               foreach t [target names] {
+               foreach t $targets {
                        if {[jtag tapisenabled [$t cget -chain-position]] == 0} {
                                continue
                        }
@@ -239,7 +254,7 @@ proc ocd_process_reset_inner { MODE } {
 
        #Pass 2 - if needed "init"
        if { 0 == [string compare init $MODE] } {
-               foreach t [target names] {
+               foreach t $targets {
                        if {[jtag tapisenabled [$t cget -chain-position]] == 0} {
                                continue
                        }
@@ -252,7 +267,7 @@ proc ocd_process_reset_inner { MODE } {
                }
        }
 
-       foreach t [ target names ] {
+       foreach t $targets {
                $t invoke-event reset-end
        }
 }