From d8421f276689ee48cb190921119ecca10559a136 Mon Sep 17 00:00:00 2001
From: zwelch <zwelch@b42882b7-edfa-0310-969c-e2dbd0fdcd60>
Date: Sun, 7 Jun 2009 05:23:40 +0000
Subject: [PATCH] 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
---
src/jtag/jtag.c | 52 ++++++++++++++++++++++++++-----------------------
1 file changed, 28 insertions(+), 24 deletions(-)
diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index 8774bbba0..0bc1c4ffb 100644
--- 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;
}
--
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