Add a new "jtag-setup" event; use for better DaVinci ICEpick support.

The model is that this fires after scanchain verification, when it's
safe to call "jtag tapenable $TAPNAME".  So it will fire as part of
non-error paths of "init" and "reset" command processing.  However it
will *NOT* trigger during "jtag_reset" processing, which skips all
scan chain verification, or after verification errors.

ALSO:  unify "enum jtag_event" scripted event notifications; and remove
JTAG_TAP_EVENT_POST_RESET, we already have JTAG_TRST_ASSERTED which
means the same thing.
---
NOTE:  the dm355 now makes a good example of how an OMAP3 might
get setup ... since I changed the default EMU0/EMU1 settings to
match TI's defaults, and thus how OMAP3 behaves.  (Though OMAP3
won't set its ETB up like this.  Not that we have support for
ETM/ETB through ADIv5 yet!)

Before this merges, I'll verify this behaves on dm365 and dm6446
boards too ... but I can't imagine any ICEpick problems there.
Those boards will need some "there's no SRST here!" solution that
Beagle boards also need.

 doc/openocd.texi         |   28 ++++++++++++++++++++++------
 src/jtag/core.c          |   15 ++++++++++++---
 src/jtag/jtag.h          |   33 +++++++++++++++++++++------------
 src/jtag/tcl.c           |   12 ++++++------
 tcl/target/ti_dm355.cfg  |    7 +++++--
 tcl/target/ti_dm365.cfg  |    3 +++
 tcl/target/ti_dm6446.cfg |    4 ++++
 7 files changed, 73 insertions(+), 29 deletions(-)

--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -2428,12 +2428,18 @@ The TAP events currently defined are:
 @itemize @bullet
 @item @b{post-reset}
 @* The TAP has just completed a JTAG reset.
-For the first such handler called, the tap is still
-in the JTAG @sc{reset} state.
+The tap may still be in the JTAG @sc{reset} state.
+Handlers for these events might perform initialization sequences
+such as issuing TCK cycles, TMS sequences to ensure
+exit from the ARM SWD mode, and more.
+
 Because the scan chain has not yet been verified, handlers for these events
 @emph{should not issue commands which scan the JTAG IR or DR registers}
 of any particular target.
 @b{NOTE:} As this is written (September 2009), nothing prevents such access.
+...@item @b{setup}
+...@* The scan chain has been reset and verified.
+This handler may enable TAPs as needed.
 @item @b{tap-disable}
 @* The TAP needs to be disabled.  This handler should
 implement @command{jtag tapdisable}
@@ -2450,7 +2456,7 @@ contents to be accurate), you might:
 
 @example
 jtag configure CHIP.jrc -event post-reset @{
-  echo "Reset done"
+  echo "JTAG Reset done"
   ... non-scan jtag operations to be done after reset
 @}
 @end example
@@ -2493,20 +2499,30 @@ does include a kind of JTAG router funct
 In OpenOCD, tap enabling/disabling is invoked by the Tcl commands
 shown below, and is implemented using TAP event handlers.
 So for example, when defining a TAP for a CPU connected to
-a JTAG router, you should define TAP event handlers using
+a JTAG router, your @file{target.cfg} file
+should define TAP event handlers using
 code that looks something like this:
 
 @example
 jtag configure CHIP.cpu -event tap-enable @{
-  echo "Enabling CPU TAP"
   ... jtag operations using CHIP.jrc
 @}
 jtag configure CHIP.cpu -event tap-disable @{
-  echo "Disabling CPU TAP"
   ... jtag operations using CHIP.jrc
 @}
 @end example
 
+Then you might want that CPU's TAP enabled almost all the time:
+
+...@example
+jtag configure $CHIP.jrc -event setup "jtag tapenable $CHIP.cpu"
+...@end example
+
+Note how that particular setup event handler declaration
+uses quotes to evaluate @code{$CHIP} when the event is configured.
+Using brackets @{ @} would cause it to be evaluated later,
+at runtime, when it might have a different value.
+
 @deffn Command {jtag tapdisable} dotted.name
 If necessary, disables the tap
 by sending it a @option{tap-disable} event.
--- a/src/jtag/core.c
+++ b/src/jtag/core.c
@@ -61,8 +61,8 @@ static int jtag_error = ERROR_OK;
 static const char *jtag_event_strings[] =
 {
        [JTAG_TRST_ASSERTED] = "TAP reset",
+       [JTAG_TAP_EVENT_SETUP] = "TAP setup",
        [JTAG_TAP_EVENT_ENABLE] = "TAP enabled",
-       [JTAG_TAP_EVENT_POST_RESET] = "TAP post reset",
        [JTAG_TAP_EVENT_DISABLE] = "TAP disabled",
 };
 
@@ -489,7 +489,7 @@ void jtag_add_tlr(void)
 
        /* NOTE: order here matches TRST path in jtag_add_reset() */
        jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
-       jtag_notify_reset();
+       jtag_notify_event(JTAG_TRST_ASSERTED);
 }
 
 void jtag_add_pathmove(int num_states, const tap_state_t *path)
@@ -704,7 +704,7 @@ void jtag_add_reset(int req_tlr_or_trst,
                         * sequence must match jtag_add_tlr().
                         */
                        jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
-                       jtag_notify_reset();
+                       jtag_notify_event(JTAG_TRST_ASSERTED);
                }
        }
 }
@@ -1232,6 +1232,7 @@ static int jtag_init_inner(struct comman
 {
        jtag_tap_t *tap;
        int retval;
+       bool issue_setup = true;
 
        LOG_DEBUG("Init JTAG chain");
 
@@ -1249,13 +1250,21 @@ static int jtag_init_inner(struct comman
        if (jtag_examine_chain() != ERROR_OK)
        {
                LOG_ERROR("Trying to use configured scan chain anyway...");
+               issue_setup = false;
        }
 
        if (jtag_validate_ircapture() != ERROR_OK)
        {
                LOG_WARNING("Errors during IR capture, continuing anyway...");
+               issue_setup = false;
        }
 
+       if (issue_setup)
+               jtag_notify_event(JTAG_TAP_EVENT_SETUP);
+       else
+               LOG_WARNING("Bypassing JTAG setup events due to errors");
+
+
        return ERROR_OK;
 }
 
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -192,23 +192,32 @@ extern unsigned jtag_tap_count(void);
 
 
 /*
- * There are three cases when JTAG_TRST_ASSERTED callback is invoked. The
- * event is invoked *after* TRST is asserted(or queued rather). It is illegal
- * to communicate with the JTAG interface during the callback(as there is
- * currently a queue being built).
+ * - TRST_ASSERTED triggers two sets of callbacks, after operations to
+ *   reset the scan chain -- via TMS+TCK signaling, or deasserting the
+ *   nTRST signal -- are queued:
  *
- * - TMS reset
- * - SRST pulls TRST
- * - TRST asserted
+ *    + Callbacks in C code fire first, patching internal state
+ *    + Then post-reset event scripts fire ... activating JTAG circuits
+ *      via TCK cycles, exiting SWD mode via TMS sequences, etc
  *
- * TAP activation/deactivation is currently implemented outside the core
- * using scripted code that understands the specific router type.
+ *   During those callbacks, scan chain contents have not been validated.
+ *   JTAG operations that address a specific TAP (primarily DR/IR scans)
+ *   must *not* be queued.
+ *
+ * - TAP_EVENT_SETUP is reported after TRST_ASSERTED, and after the scan
+ *   chain has been validated.  JTAG operations including scans that
+ *   target specific TAPs may be performed.
+ *
+ * - TAP_EVENT_ENABLE and TAP_EVENT_DISABLE implement TAP activation and
+ *   deactivation outside the core using scripted code that understands
+ *   the specific JTAG router type.  They might be triggered indirectly
+ *   from EVENT_SETUP operations.
  */
 enum jtag_event {
        JTAG_TRST_ASSERTED,
+       JTAG_TAP_EVENT_SETUP,
        JTAG_TAP_EVENT_ENABLE,
        JTAG_TAP_EVENT_DISABLE,
-       JTAG_TAP_EVENT_POST_RESET,
 };
 
 struct jtag_tap_event_action_s
@@ -643,8 +652,8 @@ extern void jtag_execute_queue_noclear(v
 /// @returns the number of times the scan queue has been flushed
 int jtag_get_flush_queue_count(void);
 
-/// Notify all TAP's about a TLR reset
-void jtag_notify_reset(void);
+/// Report Tcl event to all TAPs
+void jtag_notify_event(enum jtag_event);
 
 
 /* can be implemented by hw + sw */
--- a/src/jtag/tcl.c
+++ b/src/jtag/tcl.c
@@ -41,7 +41,8 @@
 #endif
 
 static const Jim_Nvp nvp_jtag_tap_event[] = {
-       { .value = JTAG_TAP_EVENT_POST_RESET,   .name = "post-reset" },
+       { .value = JTAG_TRST_ASSERTED,          .name = "post-reset" },
+       { .value = JTAG_TAP_EVENT_SETUP,        .name = "setup" },
        { .value = JTAG_TAP_EVENT_ENABLE,       .name = "tap-enable" },
        { .value = JTAG_TAP_EVENT_DISABLE,      .name = "tap-disable" },
 
@@ -373,7 +374,7 @@ static void jtag_tap_handle_event(jtag_t
 
        for (jteap = tap->event_action; jteap != NULL; jteap = jteap->next) {
                if (jteap->event == e) {
-                       LOG_DEBUG("JTAG tap: %s event: %d (%s) action: %s\n",
+                       LOG_DEBUG("JTAG tap: %s event: %d (%s)\n\taction: %s",
                                        tap->dotted_name,
                                        e,
                                        
Jim_Nvp_value2name_simple(nvp_jtag_tap_event, e)->name,
@@ -586,13 +587,12 @@ static int jim_jtag_command(Jim_Interp *
 }
 
 
-void jtag_notify_reset(void)
+void jtag_notify_event(enum jtag_event event)
 {
        jtag_tap_t *tap;
+
        for (tap = jtag_all_taps(); tap; tap = tap->next_tap)
-       {
-               jtag_tap_handle_event(tap, JTAG_TAP_EVENT_POST_RESET);
-       }
+               jtag_tap_handle_event(tap, event);
 }
 
 
--- a/tcl/target/ti_dm355.cfg
+++ b/tcl/target/ti_dm355.cfg
@@ -9,11 +9,11 @@ if { [info exists CHIPNAME] } {
 
 # TI boards default to EMU0/EMU1 *high* -- ARM and ETB are *disabled*
 # after JTAG reset until ICEpick is used to route them in.
-#set EMU01 "-disable"
+set EMU01 "-disable"
 
 # With EMU0/EMU1 jumpered *low* ARM and ETB are *enabled* without
 # needing any ICEpick interaction.
-set EMU01 "-enable"
+#set EMU01 "-enable"
 
 source [find target/icepick.cfg]
 
@@ -50,6 +50,9 @@ if { [info exists JRC_TAPID ] } {
 }
 jtag newtap $_CHIPNAME jrc -irlen 6 -irmask 0x3f -expected-id $_JRC_TAPID
 
+jtag configure $_CHIPNAME.jrc -event setup \
+       "jtag tapenable $_CHIPNAME.etb; jtag tapenable $_CHIPNAME.arm"
+
 ################
 
 # various symbol definitions, to avoid hard-wiring addresses
--- a/tcl/target/ti_dm365.cfg
+++ b/tcl/target/ti_dm365.cfg
@@ -46,6 +46,9 @@ if { [info exists JRC_TAPID ] } {
 }
 jtag newtap $_CHIPNAME jrc -irlen 6 -irmask 0x3f -expected-id $_JRC_TAPID
 
+jtag configure $_CHIPNAME.jrc -event setup \
+       "jtag tapenable $_CHIPNAME.etb; jtag tapenable $_CHIPNAME.arm"
+
 ################
 
 # various symbol definitions, to avoid hard-wiring addresses
--- a/tcl/target/ti_dm6446.cfg
+++ b/tcl/target/ti_dm6446.cfg
@@ -57,6 +57,10 @@ if { [info exists JRC_TAPID ] } {
 }
 jtag newtap $_CHIPNAME jrc -irlen 6 -irmask 0x3f -expected-id $_JRC_TAPID
 
+jtag configure $_CHIPNAME.jrc -event setup \
+       "jtag tapenable $_CHIPNAME.etb; jtag tapenable $_CHIPNAME.arm"
+
+################
 # GDB target:  the ARM, using SRAM1 for scratch.  SRAM0 (also 8K)
 # and the ETB memory (4K) are other options, while trace is unused.
 # Little-endian; use the OpenOCD default.

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