Factoring of jtag_examine_chain for maintainability:

- Factor end-of-chain verfication into new helper routine.
- Change 'unexpected' local variable name to 'triggered' and type to bool.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2086 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index 8774bbba09f9564dd0dafc8833ab83e26a22bfaa..0bc1c4ffbe3dafad2befcb3b45d3ee341f3ec1c0 100644 (file)
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -995,6 +995,27 @@ static void jtag_examine_chain_display(enum log_levels level, const char *msg,
                EXTRACT_MFG(idcode), EXTRACT_PART(idcode), EXTRACT_VER(idcode) );
 }
 
+/**
+ * This helper checks that remaining bits in the examined chain data are
+ * all as expected, but a single JTAG device requires only 64 bits to be
+ * read back correctly.  This can help identify and diagnose problems
+ * with the JTAG chain earlier, gives more helpful/explicit error messages.
+ */
+static void jtag_examine_chain_end(u8 *idcodes, unsigned count, unsigned max)
+{
+       bool triggered = false;
+       for ( ; count < max - 31; count += 32)
+       {
+               u32 idcode = buf_get_u32(idcodes, count, 32);
+               // do not trigger the warning if the data looks good
+               if (!triggered && (idcode == 0x000000FF || idcode == 0xFFFFFFFF))
+                       continue;
+               LOG_WARNING("Unexpected idcode after end of chain: %d 0x%08x",
+                               count, idcode);
+               triggered = true;
+       }
+}
+
 /* Try to examine chain layout according to IEEE 1149.1 §12
  */
 static int jtag_examine_chain(void)
@@ -1029,32 +1050,15 @@ static int jtag_examine_chain(void)
                }
                else
                {
-                       /* some devices, such as AVR will output all 1's instead of TDI
-                       input value at end of chain. */
+                       /*
+                        * End of chain (invalid manufacturer ID) some devices, such
+                        * as AVR will output all 1's instead of TDI input value at
+                        * end of chain.
+                        */
                        if ((idcode == 0x000000FF)||(idcode == 0xFFFFFFFF))
                        {
-                               int unexpected=0;
-                               /* End of chain (invalid manufacturer ID)
-                                *
-                                * The JTAG examine is the very first thing that happens
-                                *
-                                * A single JTAG device requires only 64 bits to be read back correctly.
-                                *
-                                * The code below adds a check that the rest of the data scanned (640 bits)
-                                * are all as expected. This helps diagnose/catch problems with the JTAG chain
-                                *
-                                * earlier and gives more helpful/explicit error messages.
-                                */
-                               for (bit_count += 32; bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;bit_count += 32)
-                               {
-                                       idcode = buf_get_u32(idcode_buffer, bit_count, 32);
-                                       if (unexpected||((idcode != 0x000000FF)&&(idcode != 0xFFFFFFFF)))
-                                       {
-                                               LOG_WARNING("Unexpected idcode after end of chain! %d 0x%08x", bit_count, idcode);
-                                               unexpected = 1;
-                                       }
-                               }
-
+                               jtag_examine_chain_end(idcode_buffer,
+                                               bit_count + 32, JTAG_MAX_CHAIN_SIZE * 32);
                                break;
                        }