Streamline Capture-IR validation code

 - Don't issue needless JTAG resets ... only do them after
   errors. Normal exit now leaves every TAP in BYPASS.

 - Fix an unlikely memory leak on one fault path.

 - Remove the oddball limitation that invalid capture LSBs
   trigger errors only for TAPs that support IDCODE.

Re the JTAG reset:  there are too many of them, and they can
(and do!) change system state.  So the needless ones should
get removed.  This one was especially pointless.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2777 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/jtag/core.c b/src/jtag/core.c
index 056fa9905ac107b72d220b07e87e48fd93a1cd4d..6177c1dc824513bb0a16c205420cc02aba3ad4c6 100644 (file)
--- a/src/jtag/core.c
+++ b/src/jtag/core.c
@@ -1058,6 +1058,9 @@ static int jtag_examine_chain(void)
  * Validate the date loaded by entry to the Capture-IR state, to help
  * find errors related to scan chain configuration (wrong IR lengths)
  * or communication.
+ *
+ * Entry state can be anything.  On non-error exit, all TAPs are in
+ * bypass mode.  On error exits, the scan chain is reset.
  */
 static int jtag_validate_ircapture(void)
 {
@@ -1066,23 +1069,21 @@ static int jtag_validate_ircapture(void)
        uint8_t *ir_test = NULL;
        scan_field_t field;
        int chain_pos = 0;
+       int retval;
 
-       tap = NULL;
-       total_ir_length = 0;
-       for (;;) {
-               tap = jtag_tap_next_enabled(tap);
-               if (tap == NULL) {
-                       break;
-               }
-               total_ir_length += tap->ir_length;
-       }
+       for (tap = NULL, total_ir_length = 0;
+                       (tap = jtag_tap_next_enabled(tap)) != NULL;
+                       total_ir_length += tap->ir_length)
+               continue;
 
+       /* increase length to add 2 bit sentinel after scan */
        total_ir_length += 2;
 
        ir_test = malloc(CEIL(total_ir_length, 8));
        if (ir_test == NULL)
                return ERROR_FAIL;
 
+       /* after this scan, all TAPs will capture BYPASS instructions */
        buf_set_ones(ir_test, total_ir_length);
 
        field.tap = NULL;
@@ -1090,14 +1091,12 @@ static int jtag_validate_ircapture(void)
        field.out_value = ir_test;
        field.in_value = ir_test;
 
+       jtag_add_plain_ir_scan(1, &field, TAP_IDLE);
 
-       jtag_add_plain_ir_scan(1, &field, TAP_IRPAUSE);
-       jtag_add_tlr();
-
-       int retval;
+       LOG_DEBUG("IR capture validation scan");
        retval = jtag_execute_queue();
        if (retval != ERROR_OK)
-               return retval;
+               goto done;
 
        tap = NULL;
        chain_pos = 0;
@@ -1119,14 +1118,9 @@ static int jtag_validate_ircapture(void)
                        LOG_ERROR("%s: IR capture error; saw 0x%s not 0x..1",
                                        jtag_tap_name(tap), cbuf);
 
-                       /* Fail only if we have IDCODE for this device.
-                        * REVISIT -- why not fail-always?
-                        */
-                       if (tap->hasidcode) {
-                               free(cbuf);
-                               free(ir_test);
-                               return ERROR_JTAG_INIT_FAILED;
-                       }
+                       free(cbuf);
+                       retval = ERROR_JTAG_INIT_FAILED;
+                       goto done;
                }
                chain_pos += tap->ir_length;
        }
@@ -1140,13 +1134,16 @@ static int jtag_validate_ircapture(void)
                LOG_ERROR("IR capture error at bit %d, saw 0x%s not 0x...3",
                                chain_pos, cbuf);
                free(cbuf);
-               free(ir_test);
-               return ERROR_JTAG_INIT_FAILED;
+               retval = ERROR_JTAG_INIT_FAILED;
        }
 
+done:
        free(ir_test);
-
-       return ERROR_OK;
+       if (retval != ERROR_OK) {
+               jtag_add_tlr();
+               jtag_execute_queue();
+       }
+       return retval;
 }