static const char *jtag_event_strings[] =
{
- [JTAG_TRST_ASSERTED] = "JTAG controller reset (TLR or TRST)",
+ [JTAG_TRST_ASSERTED] = "TAP reset",
[JTAG_TAP_EVENT_ENABLE] = "TAP enabled",
- [JTAG_TAP_EVENT_POST_RESET] = "post reset",
+ [JTAG_TAP_EVENT_POST_RESET] = "TAP post reset",
[JTAG_TAP_EVENT_DISABLE] = "TAP disabled",
};
{
jtag_tap_t *tap = priv;
- LOG_DEBUG("TAP %s event %s", tap->dotted_name,
- jtag_event_strings[event]);
-
if (event == JTAG_TRST_ASSERTED)
{
tap->enabled = !tap->disabled_after_reset;
alive_sleep(us/1000);
}
-/// maximum number of JTAG devices expected in the chain
+/* Maximum number of enabled JTAG devices we expect in the scan chain,
+ * plus one (to detect garbage at the end). Devices that don't support
+ * IDCODE take up fewer bits, possibly allowing a few more devices.
+ */
#define JTAG_MAX_CHAIN_SIZE 20
#define EXTRACT_MFG(X) (((X) & 0xffe) >> 1)
#define EXTRACT_PART(X) (((X) & 0xffff000) >> 12)
#define EXTRACT_VER(X) (((X) & 0xf0000000) >> 28)
+/* A reserved manufacturer ID is used in END_OF_CHAIN_FLAG, so we
+ * know that no valid TAP will have it as an IDCODE value.
+ */
+#define END_OF_CHAIN_FLAG 0x000000ff
+
static int jtag_examine_chain_execute(uint8_t *idcode_buffer, unsigned num_idcode)
{
scan_field_t field = {
// initialize to the end of chain ID value
for (unsigned i = 0; i < JTAG_MAX_CHAIN_SIZE; i++)
- buf_set_u32(idcode_buffer, i * 32, 32, 0x000000FF);
+ buf_set_u32(idcode_buffer, i * 32, 32, END_OF_CHAIN_FLAG);
jtag_add_plain_dr_scan(1, &field, TAP_DRPAUSE);
jtag_add_tlr();
static bool jtag_idcode_is_final(uint32_t idcode)
{
- return idcode == 0x000000FF || idcode == 0xFFFFFFFF;
+ /*
+ * Some devices, such as AVR8, will output all 1's instead
+ * of TDI input value at end of chain. Allow those values
+ * instead of failing.
+ */
+ return idcode == END_OF_CHAIN_FLAG || idcode == 0xFFFFFFFF;
}
/**
* 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.
+ * Returns TRUE iff garbage was found.
*/
-static void jtag_examine_chain_end(uint8_t *idcodes, unsigned count, unsigned max)
+static bool jtag_examine_chain_end(uint8_t *idcodes, unsigned count, unsigned max)
{
bool triggered = false;
for (; count < max - 31; count += 32)
count, (unsigned int)idcode);
triggered = true;
}
+ return triggered;
}
static bool jtag_examine_chain_match_tap(const struct jtag_tap_s *tap)
{
- if (0 == tap->expected_ids_cnt)
- {
- /// @todo Enable LOG_INFO to ask for reports about unknown TAP IDs.
-#if 0
- LOG_INFO("Uknown JTAG TAP ID: 0x%08x", tap->idcode)
- LOG_INFO("Please report the chip name and reported ID code to the openocd project");
-#endif
+ /* ignore expected BYPASS codes; warn otherwise */
+ if (0 == tap->expected_ids_cnt && !tap->idcode)
return true;
- }
/* Loop over the expected identification codes and test for a match */
uint8_t ii;
for (ii = 0; ii < tap->expected_ids_cnt; ii++)
{
if (tap->idcode == tap->expected_ids[ii])
- break;
+ return true;
}
/* If none of the expected ids matched, log an error */
- if (ii != tap->expected_ids_cnt)
- {
- LOG_DEBUG("JTAG Tap/device matched");
- return true;
- }
- jtag_examine_chain_display(LOG_LVL_ERROR, "got",
+ jtag_examine_chain_display(LOG_LVL_ERROR, "UNEXPECTED",
tap->dotted_name, tap->idcode);
for (ii = 0; ii < tap->expected_ids_cnt; ii++)
{
}
/* Try to examine chain layout according to IEEE 1149.1 ยง12
+ * This is called a "blind interrogation" of the scan chain.
*/
static int jtag_examine_chain(void)
{
uint8_t idcode_buffer[JTAG_MAX_CHAIN_SIZE * 4];
- unsigned device_count = 0;
+ unsigned bit_count;
+ /* DR scan to collect BYPASS or IDCODE register contents.
+ * Then make sure the scan data has both ones and zeroes.
+ */
jtag_examine_chain_execute(idcode_buffer, JTAG_MAX_CHAIN_SIZE);
-
if (!jtag_examine_chain_check(idcode_buffer, JTAG_MAX_CHAIN_SIZE))
return ERROR_JTAG_INIT_FAILED;
return ERROR_JTAG_INIT_FAILED;
}
- for (unsigned bit_count = 0;
+ for (bit_count = 0;
tap && bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;
tap = jtag_tap_next_enabled(tap))
{
if ((idcode & 1) == 0)
{
/* LSB must not be 0, this indicates a device in bypass */
- LOG_WARNING("Tap/Device does not have IDCODE");
+ LOG_WARNING("TAP %s does not have IDCODE",
+ tap->dotted_name);
idcode = 0;
tap->hasidcode = false;
}
else
{
+ /* Friendly devices support IDCODE */
tap->hasidcode = true;
-
- /*
- * 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 (jtag_idcode_is_final(idcode))
- {
- jtag_examine_chain_end(idcode_buffer,
- bit_count + 32, JTAG_MAX_CHAIN_SIZE * 32);
- break;
- }
-
jtag_examine_chain_display(LOG_LVL_INFO, "tap/device found",
- tap ? tap->dotted_name : "(not-named)",
- idcode);
+ tap->dotted_name, idcode);
bit_count += 32;
}
- device_count++;
- if (!tap)
- continue;
-
tap->idcode = idcode;
// ensure the TAP ID does matches what was expected
return ERROR_JTAG_INIT_FAILED;
}
- /* see if number of discovered devices matches configuration */
- if (device_count != jtag_tap_count_enabled())
- {
- LOG_ERROR("number of discovered devices in JTAG chain (%i) "
- "does not match (enabled) configuration (%i), total taps: %d",
- device_count, jtag_tap_count_enabled(), jtag_tap_count());
- LOG_ERROR("check the config file and ensure proper JTAG communication"
- " (connections, speed, ...)");
+ /* Fail if too many TAPs were enabled for us to verify them all. */
+ if (tap) {
+ LOG_ERROR("Too many TAPs enabled; '%s' ignored.",
+ tap->dotted_name);
+ return ERROR_JTAG_INIT_FAILED;
+ }
+
+ /* After those IDCODE or BYPASS register values should be
+ * only the data we fed into the scan chain.
+ */
+ if (jtag_examine_chain_end(idcode_buffer, bit_count,
+ 8 * sizeof(idcode_buffer))) {
+ LOG_ERROR("double-check your JTAG setup (interface, "
+ "speed, TAPs, ...)");
return ERROR_JTAG_INIT_FAILED;
}
return ERROR_OK;
}
-int jtag_validate_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.
+ */
+static int jtag_validate_ircapture(void)
{
jtag_tap_t *tap;
int total_ir_length = 0;
}
total_ir_length += 2;
+
ir_test = malloc(CEIL(total_ir_length, 8));
+ if (ir_test == NULL)
+ return ERROR_FAIL;
+
buf_set_ones(ir_test, total_ir_length);
field.tap = NULL;
break;
}
+ /* Validate the two LSBs, which must be 01 per JTAG spec.
+ * REVISIT we might be able to verify some MSBs too, using
+ * ircapture/irmask attributes.
+ */
val = buf_get_u32(ir_test, chain_pos, 2);
- /* Only fail this check if we have IDCODE for this device */
- if ((val != 0x1)&&(tap->hasidcode))
- {
+ if (val != 1) {
char *cbuf = buf_to_str(ir_test, total_ir_length, 16);
- LOG_ERROR("Could not validate JTAG scan chain, IR mismatch, scan returned 0x%s. tap=%s pos=%d expected 0x1 got %0x", cbuf, jtag_tap_name(tap), chain_pos, val);
- free(cbuf);
- free(ir_test);
- return ERROR_JTAG_INIT_FAILED;
+
+ 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;
+ }
}
chain_pos += tap->ir_length;
}
+ /* verify the '11' sentinel we wrote is returned at the end */
val = buf_get_u32(ir_test, chain_pos, 2);
if (val != 0x3)
{
char *cbuf = buf_to_str(ir_test, total_ir_length, 16);
- LOG_ERROR("Could not validate end of JTAG scan chain, IR mismatch, scan returned 0x%s. pos=%d expected 0x3 got %0x", cbuf, chain_pos, val);
+
+ 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;
{
assert(0 != tap->ir_length);
+ /// @todo fix, this allocates one byte per bit for all three fields!
tap->expected = malloc(tap->ir_length);
tap->expected_mask = malloc(tap->ir_length);
tap->cur_instr = malloc(tap->ir_length);
LOG_DEBUG("Created Tap: %s @ abs position %d, "
"irlen %d, capture: 0x%x mask: 0x%x", tap->dotted_name,
tap->abs_chain_position, tap->ir_length,
- (unsigned int)(tap->ir_capture_value), (unsigned int)(tap->ir_capture_mask));
+ (unsigned) tap->ir_capture_value,
+ (unsigned) tap->ir_capture_mask);
jtag_tap_add(tap);
}
jtag_unregister_event_callback(&jtag_reset_callback, tap);
/// @todo is anything missing? no memory leaks please
+ free((void *)tap->expected);
free((void *)tap->expected_ids);
free((void *)tap->chip);
free((void *)tap->tapname);
LOG_ERROR("trying to validate configured JTAG chain anyway...");
}
- if (jtag_validate_chain() != ERROR_OK)
+ if (jtag_validate_ircapture() != ERROR_OK)
{
- LOG_WARNING("Could not validate JTAG chain, continuing anyway...");
+ LOG_WARNING("Errors during IR capture, continuing anyway...");
}
return ERROR_OK;
projects / fw / openocd / blobdiff