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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
This commit is contained in:
zwelch 2009-06-07 05:23:40 +00:00
parent feb865f9ee
commit d8421f2766
1 changed files with 28 additions and 24 deletions
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52
src/jtag/jtag.c
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@ -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;
}